[u/mdw/putty] / terminal.c

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

#include <time.h>
#include <assert.h>
#include "putty.h"
#include "terminal.h"

#define poslt(p1,p2) ( (p1).y < (p2).y || ( (p1).y == (p2).y && (p1).x < (p2).x ) )
#define posle(p1,p2) ( (p1).y < (p2).y || ( (p1).y == (p2).y && (p1).x <= (p2).x ) )
#define poseq(p1,p2) ( (p1).y == (p2).y && (p1).x == (p2).x )
#define posdiff(p1,p2) ( ((p1).y - (p2).y) * (term->cols+1) + (p1).x - (p2).x )

/* Product-order comparisons for rectangular block selection. */
#define posPlt(p1,p2) ( (p1).y <= (p2).y && (p1).x < (p2).x )
#define posPle(p1,p2) ( (p1).y <= (p2).y && (p1).x <= (p2).x )

#define incpos(p) ( (p).x == term->cols ? ((p).x = 0, (p).y++, 1) : ((p).x++, 0) )
#define decpos(p) ( (p).x == 0 ? ((p).x = term->cols, (p).y--, 1) : ((p).x--, 0) )

#define VT52_PLUS

#define CL_ANSIMIN      0x0001         /* Codes in all ANSI like terminals. */
#define CL_VT100        0x0002         /* VT100 */
#define CL_VT100AVO     0x0004         /* VT100 +AVO; 132x24 (not 132x14) & attrs */
#define CL_VT102        0x0008         /* VT102 */
#define CL_VT220        0x0010         /* VT220 */
#define CL_VT320        0x0020         /* VT320 */
#define CL_VT420        0x0040         /* VT420 */
#define CL_VT510        0x0080         /* VT510, NB VT510 includes ANSI */
#define CL_VT340TEXT    0x0100         /* VT340 extensions that appear in the VT420 */
#define CL_SCOANSI      0x1000         /* SCOANSI not in ANSIMIN. */
#define CL_ANSI         0x2000         /* ANSI ECMA-48 not in the VT100..VT420 */
#define CL_OTHER        0x4000         /* Others, Xterm, linux, putty, dunno, etc */

#define TM_VT100        (CL_ANSIMIN|CL_VT100)
#define TM_VT100AVO     (TM_VT100|CL_VT100AVO)
#define TM_VT102        (TM_VT100AVO|CL_VT102)
#define TM_VT220        (TM_VT102|CL_VT220)
#define TM_VTXXX        (TM_VT220|CL_VT340TEXT|CL_VT510|CL_VT420|CL_VT320)
#define TM_SCOANSI      (CL_ANSIMIN|CL_SCOANSI)

#define TM_PUTTY        (0xFFFF)

#define compatibility(x) \
    if ( ((CL_##x)&term->compatibility_level) == 0 ) {  \
       term->termstate=TOPLEVEL;                        \
       break;                                           \
    }
#define compatibility2(x,y) \
    if ( ((CL_##x|CL_##y)&term->compatibility_level) == 0 ) { \
       term->termstate=TOPLEVEL;                        \
       break;                                           \
    }

#define has_compat(x) ( ((CL_##x)&term->compatibility_level) != 0 )

#define sel_nl_sz  (sizeof(sel_nl)/sizeof(wchar_t))
const wchar_t sel_nl[] = SEL_NL;

/*
 * Fetch the character at a particular position in a line array,
 * for purposes of `wordtype'. The reason this isn't just a simple
 * array reference is that if the character we find is UCSWIDE,
 * then we must look one space further to the left.
 */
#define UCSGET(a, x) \
    ( (x)>0 && ((a)[(x)] & (CHAR_MASK | CSET_MASK)) == UCSWIDE ? \
        (a)[(x)-1] : (a)[(x)] )

/*
 * Internal prototypes.
 */
static unsigned long *resizeline(unsigned long *, int);
static unsigned long *lineptr(Terminal *, int, int);
static void do_paint(Terminal *, Context, int);
static void erase_lots(Terminal *, int, int, int);
static void swap_screen(Terminal *, int, int, int);
static void update_sbar(Terminal *);
static void deselect(Terminal *);
static void term_print_finish(Terminal *);
#ifdef OPTIMISE_SCROLL
static void scroll_display(Terminal *, int, int, int);
#endif /* OPTIMISE_SCROLL */

/*
 * Resize a line to make it `cols' columns wide.
 */
static unsigned long *resizeline(unsigned long *line, int cols)
{
    int i, oldlen;
    unsigned long lineattrs;

    if (line[0] != (unsigned long)cols) {
        /*
         * This line is the wrong length, which probably means it
         * hasn't been accessed since a resize. Resize it now.
         */
        oldlen = line[0];
        lineattrs = line[oldlen + 1];
        line = srealloc(line, TSIZE * (2 + cols));
        line[0] = cols;
        for (i = oldlen; i < cols; i++)
            line[i + 1] = ERASE_CHAR;
        line[cols + 1] = lineattrs & LATTR_MODE;
    }

    return line;
}

/*
 * Retrieve a line of the screen or of the scrollback, according to
 * whether the y coordinate is non-negative or negative
 * (respectively).
 */
static unsigned long *lineptr(Terminal *term, int y, int lineno)
{
    unsigned long *line, *newline;
    tree234 *whichtree;
    int treeindex;

    if (y >= 0) {
        whichtree = term->screen;
        treeindex = y;
    } else {
        whichtree = term->scrollback;
        treeindex = y + count234(term->scrollback);
    }
    line = index234(whichtree, treeindex);

    /* We assume that we don't screw up and retrieve something out of range. */
    assert(line != NULL);

    newline = resizeline(line, term->cols);
    if (newline != line) {
        delpos234(whichtree, treeindex);
        addpos234(whichtree, newline, treeindex);
        line = newline;
    }

    return line + 1;
}

#define lineptr(x) lineptr(term,x,__LINE__)

/*
 * Set up power-on settings for the terminal.
 */
static void power_on(Terminal *term)
{
    term->curs.x = term->curs.y = 0;
    term->alt_x = term->alt_y = 0;
    term->savecurs.x = term->savecurs.y = 0;
    term->alt_t = term->marg_t = 0;
    if (term->rows != -1)
        term->alt_b = term->marg_b = term->rows - 1;
    else
        term->alt_b = term->marg_b = 0;
    if (term->cols != -1) {
        int i;
        for (i = 0; i < term->cols; i++)
            term->tabs[i] = (i % 8 == 0 ? TRUE : FALSE);
    }
    term->alt_om = term->dec_om = term->cfg->dec_om;
    term->alt_ins = term->insert = FALSE;
    term->alt_wnext = term->wrapnext = term->save_wnext = FALSE;
    term->alt_wrap = term->wrap = term->cfg->wrap_mode;
    term->alt_cset = term->cset = term->save_cset = 0;
    term->alt_utf = term->utf = term->save_utf = 0;
    term->utf_state = 0;
    term->alt_sco_acs = term->sco_acs = term->save_sco_acs = 0;
    term->cset_attr[0] = term->cset_attr[1] = term->save_csattr = ATTR_ASCII;
    term->rvideo = 0;
    term->in_vbell = FALSE;
    term->cursor_on = 1;
    term->big_cursor = 0;
    term->save_attr = term->curr_attr = ATTR_DEFAULT;
    term->term_editing = term->term_echoing = FALSE;
    term->app_cursor_keys = term->cfg->app_cursor;
    term->app_keypad_keys = term->cfg->app_keypad;
    term->use_bce = term->cfg->bce;
    term->blink_is_real = term->cfg->blinktext;
    term->erase_char = ERASE_CHAR;
    term->alt_which = 0;
    term_print_finish(term);
    {
        int i;
        for (i = 0; i < 256; i++)
            term->wordness[i] = term->cfg->wordness[i];
    }
    if (term->screen) {
        swap_screen(term, 1, FALSE, FALSE);
        erase_lots(term, FALSE, TRUE, TRUE);
        swap_screen(term, 0, FALSE, FALSE);
        erase_lots(term, FALSE, TRUE, TRUE);
    }
}

/*
 * Force a screen update.
 */
void term_update(Terminal *term)
{
    Context ctx;
    ctx = get_ctx(term->frontend);
    if (ctx) {
        int need_sbar_update = term->seen_disp_event;
        if (term->seen_disp_event && term->cfg->scroll_on_disp) {
            term->disptop = 0;         /* return to main screen */
            term->seen_disp_event = 0;
            need_sbar_update = TRUE;
        }
        if (need_sbar_update)
            update_sbar(term);
        do_paint(term, ctx, TRUE);
        sys_cursor(term->frontend, term->curs.x, term->curs.y - term->disptop);
        free_ctx(ctx);
    }
}

/*
 * Called from front end when a keypress occurs, to trigger
 * anything magical that needs to happen in that situation.
 */
void term_seen_key_event(Terminal *term)
{
    /*
     * On any keypress, clear the bell overload mechanism
     * completely, on the grounds that large numbers of
     * beeps coming from deliberate key action are likely
     * to be intended (e.g. beeps from filename completion
     * blocking repeatedly).
     */
    term->beep_overloaded = FALSE;
    while (term->beephead) {
        struct beeptime *tmp = term->beephead;
        term->beephead = tmp->next;
        sfree(tmp);
    }
    term->beeptail = NULL;
    term->nbeeps = 0;

    /*
     * Reset the scrollback on keypress, if we're doing that.
     */
    if (term->cfg->scroll_on_key) {
        term->disptop = 0;             /* return to main screen */
        term->seen_disp_event = 1;
    }
}

/*
 * Same as power_on(), but an external function.
 */
void term_pwron(Terminal *term)
{
    power_on(term);
    if (term->ldisc)                   /* cause ldisc to notice changes */
        ldisc_send(term->ldisc, NULL, 0, 0);
    fix_cpos;
    term->disptop = 0;
    deselect(term);
    term_update(term);
}

/*
 * When the user reconfigures us, we need to check the forbidden-
 * alternate-screen config option, disable raw mouse mode if the
 * user has disabled mouse reporting, and abandon a print job if
 * the user has disabled printing.
 */
void term_reconfig(Terminal *term)
{
    if (term->cfg->no_alt_screen)
        swap_screen(term, 0, FALSE, FALSE);
    if (term->cfg->no_mouse_rep) {
        term->xterm_mouse = 0;
        set_raw_mouse_mode(term->frontend, 0);
    }
    if (term->cfg->no_remote_charset) {
        term->cset_attr[0] = term->cset_attr[1] = ATTR_ASCII;
        term->sco_acs = term->alt_sco_acs = 0;
        term->utf = 0;
    }
    if (!*term->cfg->printer) {
        term_print_finish(term);
    }
}

/*
 * Clear the scrollback.
 */
void term_clrsb(Terminal *term)
{
    unsigned long *line;
    term->disptop = 0;
    while ((line = delpos234(term->scrollback, 0)) != NULL) {
        sfree(line);
    }
    update_sbar(term);
}

/*
 * Initialise the terminal.
 */
Terminal *term_init(Config *mycfg, void *frontend)
{
    Terminal *term;

    /*
     * Allocate a new Terminal structure and initialise the fields
     * that need it.
     */
    term = smalloc(sizeof(Terminal));
    term->frontend = frontend;
    term->cfg = mycfg;
    term->logctx = NULL;
    term->compatibility_level = TM_PUTTY;
    strcpy(term->id_string, "\033[?6c");
    term->last_blink = term->last_tblink = 0;
    term->paste_buffer = NULL;
    term->paste_len = 0;
    term->last_paste = 0;
    bufchain_init(&term->inbuf);
    bufchain_init(&term->printer_buf);
    term->printing = term->only_printing = FALSE;
    term->print_job = NULL;
    term->vt52_mode = FALSE;
    term->cr_lf_return = FALSE;
    term->seen_disp_event = FALSE;
    term->xterm_mouse = term->mouse_is_down = FALSE;
    term->reset_132 = FALSE;
    term->blinker = term->tblinker = 0;
    term->has_focus = 1;
    term->repeat_off = FALSE;
    term->termstate = TOPLEVEL;
    term->selstate = NO_SELECTION;
    term->curstype = 0;

    term->screen = term->alt_screen = term->scrollback = NULL;
    term->disptop = 0;
    term->disptext = term->dispcurs = NULL;
    term->tabs = NULL;
    deselect(term);
    term->rows = term->cols = -1;
    power_on(term);
    term->beephead = term->beeptail = NULL;
    term->nbeeps = 0;
    term->lastbeep = FALSE;
    term->beep_overloaded = FALSE;
    term->attr_mask = 0xffffffff;
    term->resize_fn = NULL;
    term->resize_ctx = NULL;

    return term;
}

/*
 * Set up the terminal for a given size.
 */
void term_size(Terminal *term, int newrows, int newcols, int newsavelines)
{
    tree234 *newalt;
    unsigned long *newdisp, *line;
    int i, j;
    int sblen;
    int save_alt_which = term->alt_which;

    if (newrows == term->rows && newcols == term->cols &&
        newsavelines == term->savelines)
        return;                        /* nothing to do */

    deselect(term);
    swap_screen(term, 0, FALSE, FALSE);

    term->alt_t = term->marg_t = 0;
    term->alt_b = term->marg_b = newrows - 1;

    if (term->rows == -1) {
        term->scrollback = newtree234(NULL);
        term->screen = newtree234(NULL);
        term->rows = 0;
    }

    /*
     * Resize the screen and scrollback. We only need to shift
     * lines around within our data structures, because lineptr()
     * will take care of resizing each individual line if
     * necessary. So:
     * 
     *  - If the new screen and the old screen differ in length, we
     *    must shunt some lines in from the scrollback or out to
     *    the scrollback.
     * 
     *  - If doing that fails to provide us with enough material to
     *    fill the new screen (i.e. the number of rows needed in
     *    the new screen exceeds the total number in the previous
     *    screen+scrollback), we must invent some blank lines to
     *    cover the gap.
     * 
     *  - Then, if the new scrollback length is less than the
     *    amount of scrollback we actually have, we must throw some
     *    away.
     */
    sblen = count234(term->scrollback);
    /* Do this loop to expand the screen if newrows > rows */
    for (i = term->rows; i < newrows; i++) {
        if (sblen > 0) {
            line = delpos234(term->scrollback, --sblen);
        } else {
            line = smalloc(TSIZE * (newcols + 2));
            line[0] = newcols;
            for (j = 0; j <= newcols; j++)
                line[j + 1] = ERASE_CHAR;
        }
        addpos234(term->screen, line, 0);
    }
    /* Do this loop to shrink the screen if newrows < rows */
    for (i = newrows; i < term->rows; i++) {
        line = delpos234(term->screen, 0);
        addpos234(term->scrollback, line, sblen++);
    }
    assert(count234(term->screen) == newrows);
    while (sblen > newsavelines) {
        line = delpos234(term->scrollback, 0);
        sfree(line);
        sblen--;
    }
    assert(count234(term->scrollback) <= newsavelines);
    term->disptop = 0;

    newdisp = smalloc(newrows * (newcols + 1) * TSIZE);
    for (i = 0; i < newrows * (newcols + 1); i++)
        newdisp[i] = ATTR_INVALID;
    sfree(term->disptext);
    term->disptext = newdisp;
    term->dispcurs = NULL;

    newalt = newtree234(NULL);
    for (i = 0; i < newrows; i++) {
        line = smalloc(TSIZE * (newcols + 2));
        line[0] = newcols;
        for (j = 0; j <= newcols; j++)
            line[j + 1] = term->erase_char;
        addpos234(newalt, line, i);
    }
    if (term->alt_screen) {
        while (NULL != (line = delpos234(term->alt_screen, 0)))
            sfree(line);
        freetree234(term->alt_screen);
    }
    term->alt_screen = newalt;

    term->tabs = srealloc(term->tabs, newcols * sizeof(*term->tabs));
    {
        int i;
        for (i = (term->cols > 0 ? term->cols : 0); i < newcols; i++)
            term->tabs[i] = (i % 8 == 0 ? TRUE : FALSE);
    }

    if (term->rows > 0)
        term->curs.y += newrows - term->rows;
    if (term->curs.y < 0)
        term->curs.y = 0;
    if (term->curs.y >= newrows)
        term->curs.y = newrows - 1;
    if (term->curs.x >= newcols)
        term->curs.x = newcols - 1;
    term->alt_x = term->alt_y = 0;
    term->wrapnext = term->alt_wnext = FALSE;

    term->rows = newrows;
    term->cols = newcols;
    term->savelines = newsavelines;
    fix_cpos;

    swap_screen(term, save_alt_which, FALSE, FALSE);

    update_sbar(term);
    term_update(term);
    if (term->resize_fn)
        term->resize_fn(term->resize_ctx, term->cols, term->rows);
}

/*
 * Hand a function and context pointer to the terminal which it can
 * use to notify a back end of resizes.
 */
void term_provide_resize_fn(Terminal *term,
                            void (*resize_fn)(void *, int, int),
                            void *resize_ctx)
{
    term->resize_fn = resize_fn;
    term->resize_ctx = resize_ctx;
    if (term->cols > 0 && term->rows > 0)
        resize_fn(resize_ctx, term->cols, term->rows);
}

/*
 * Swap screens. If `reset' is TRUE and we have been asked to
 * switch to the alternate screen, we must bring most of its
 * configuration from the main screen and erase the contents of the
 * alternate screen completely. (This is even true if we're already
 * on it! Blame xterm.)
 */
static void swap_screen(Terminal *term, int which, int reset, int keep_cur_pos)
{
    int t;
    tree234 *ttr;

    if (!which)
        reset = FALSE;                 /* do no weird resetting if which==0 */

    if (which != term->alt_which) {
        term->alt_which = which;

        ttr = term->alt_screen;
        term->alt_screen = term->screen;
        term->screen = ttr;
        t = term->curs.x;
        if (!reset && !keep_cur_pos)
            term->curs.x = term->alt_x;
        term->alt_x = t;
        t = term->curs.y;
        if (!reset && !keep_cur_pos)
            term->curs.y = term->alt_y;
        term->alt_y = t;
        t = term->marg_t;
        if (!reset) term->marg_t = term->alt_t;
        term->alt_t = t;
        t = term->marg_b;
        if (!reset) term->marg_b = term->alt_b;
        term->alt_b = t;
        t = term->dec_om;
        if (!reset) term->dec_om = term->alt_om;
        term->alt_om = t;
        t = term->wrap;
        if (!reset) term->wrap = term->alt_wrap;
        term->alt_wrap = t;
        t = term->wrapnext;
        if (!reset) term->wrapnext = term->alt_wnext;
        term->alt_wnext = t;
        t = term->insert;
        if (!reset) term->insert = term->alt_ins;
        term->alt_ins = t;
        t = term->cset;
        if (!reset) term->cset = term->alt_cset;
        term->alt_cset = t;
        t = term->utf;
        if (!reset) term->utf = term->alt_utf;
        term->alt_utf = t;
        t = term->sco_acs;
        if (!reset) term->sco_acs = term->alt_sco_acs;
        term->alt_sco_acs = t;
    }

    if (reset && term->screen) {
        /*
         * Yes, this _is_ supposed to honour background-colour-erase.
         */
        erase_lots(term, FALSE, TRUE, TRUE);
    }

    /*
     * This might not be possible if we're called during
     * initialisation.
     */
    if (term->screen)
        fix_cpos;
}

/*
 * Update the scroll bar.
 */
static void update_sbar(Terminal *term)
{
    int nscroll;

    nscroll = count234(term->scrollback);

    set_sbar(term->frontend, nscroll + term->rows,
             nscroll + term->disptop, term->rows);
}

/*
 * Check whether the region bounded by the two pointers intersects
 * the scroll region, and de-select the on-screen selection if so.
 */
static void check_selection(Terminal *term, pos from, pos to)
{
    if (poslt(from, term->selend) && poslt(term->selstart, to))
        deselect(term);
}

/*
 * Scroll the screen. (`lines' is +ve for scrolling forward, -ve
 * for backward.) `sb' is TRUE if the scrolling is permitted to
 * affect the scrollback buffer.
 * 
 * NB this function invalidates all pointers into lines of the
 * screen data structures. In particular, you MUST call fix_cpos
 * after calling scroll() and before doing anything else that
 * uses the cpos shortcut pointer.
 */
static void scroll(Terminal *term, int topline, int botline, int lines, int sb)
{
    unsigned long *line, *line2;
    int i, seltop, olddisptop, shift;

    if (topline != 0 || term->alt_which != 0)
        sb = FALSE;

    olddisptop = term->disptop;
    shift = lines;
    if (lines < 0) {
        while (lines < 0) {
            line = delpos234(term->screen, botline);
            line = resizeline(line, term->cols);
            for (i = 0; i < term->cols; i++)
                line[i + 1] = term->erase_char;
            line[term->cols + 1] = 0;
            addpos234(term->screen, line, topline);

            if (term->selstart.y >= topline && term->selstart.y <= botline) {
                term->selstart.y++;
                if (term->selstart.y > botline) {
                    term->selstart.y = botline;
                    term->selstart.x = 0;
                }
            }
            if (term->selend.y >= topline && term->selend.y <= botline) {
                term->selend.y++;
                if (term->selend.y > botline) {
                    term->selend.y = botline;
                    term->selend.x = 0;
                }
            }

            lines++;
        }
    } else {
        while (lines > 0) {
            line = delpos234(term->screen, topline);
            if (sb && term->savelines > 0) {
                int sblen = count234(term->scrollback);
                /*
                 * We must add this line to the scrollback. We'll
                 * remove a line from the top of the scrollback to
                 * replace it, or allocate a new one if the
                 * scrollback isn't full.
                 */
                if (sblen == term->savelines) {
                    sblen--, line2 = delpos234(term->scrollback, 0);
                } else {
                    line2 = smalloc(TSIZE * (term->cols + 2));
                    line2[0] = term->cols;
                }
                addpos234(term->scrollback, line, sblen);
                line = line2;

                /*
                 * If the user is currently looking at part of the
                 * scrollback, and they haven't enabled any options
                 * that are going to reset the scrollback as a
                 * result of this movement, then the chances are
                 * they'd like to keep looking at the same line. So
                 * we move their viewpoint at the same rate as the
                 * scroll, at least until their viewpoint hits the
                 * top end of the scrollback buffer, at which point
                 * we don't have the choice any more.
                 * 
                 * Thanks to Jan Holmen Holsten for the idea and
                 * initial implementation.
                 */
                if (term->disptop > -term->savelines && term->disptop < 0)
                    term->disptop--;
            }
            line = resizeline(line, term->cols);
            for (i = 0; i < term->cols; i++)
                line[i + 1] = term->erase_char;
            line[term->cols + 1] = 0;
            addpos234(term->screen, line, botline);

            /*
             * If the selection endpoints move into the scrollback,
             * we keep them moving until they hit the top. However,
             * of course, if the line _hasn't_ moved into the
             * scrollback then we don't do this, and cut them off
             * at the top of the scroll region.
             * 
             * This applies to selstart and selend (for an existing
             * selection), and also selanchor (for one being
             * selected as we speak).
             */
            seltop = sb ? -term->savelines : topline;

            if (term->selstart.y >= seltop &&
                term->selstart.y <= botline) {
                term->selstart.y--;
                if (term->selstart.y < seltop) {
                    term->selstart.y = seltop;
                    term->selstart.x = 0;
                }
            }
            if (term->selend.y >= seltop && term->selend.y <= botline) {
                term->selend.y--;
                if (term->selend.y < seltop) {
                    term->selend.y = seltop;
                    term->selend.x = 0;
                }
            }
            if (term->selanchor.y >= seltop && term->selanchor.y <= botline) {
                term->selanchor.y--;
                if (term->selanchor.y < seltop) {
                    term->selanchor.y = seltop;
                    term->selanchor.x = 0;
                }
            }

            lines--;
        }
    }
#ifdef OPTIMISE_SCROLL
    shift += term->disptop - olddisptop;
    if (shift < term->rows && shift > -term->rows && shift != 0)
        scroll_display(term, topline, botline, shift);
#endif /* OPTIMISE_SCROLL */
}

#ifdef OPTIMISE_SCROLL
/*
 * Scroll the physical display, and our conception of it in disptext.
 */
static void scroll_display(Terminal *term, int topline, int botline, int lines)
{
    unsigned long *start, *end;
    int distance, size, i;

    start = term->disptext + topline * (term->cols + 1);
    end = term->disptext + (botline + 1) * (term->cols + 1);
    distance = (lines > 0 ? lines : -lines) * (term->cols + 1);
    size = end - start - distance;
    if (lines > 0) {
        memmove(start, start + distance, size * TSIZE);
        if (term->dispcurs >= start + distance &&
            term->dispcurs <= start + distance + size)
            term->dispcurs -= distance;
        for (i = 0; i < distance; i++)
            (start + size)[i] |= ATTR_INVALID;
    } else {
        memmove(start + distance, start, size * TSIZE);
        if (term->dispcurs >= start && term->dispcurs <= start + size)
            term->dispcurs += distance;
        for (i = 0; i < distance; i++)
            start[i] |= ATTR_INVALID;
    }
    do_scroll(term->frontend, topline, botline, lines);
}
#endif /* OPTIMISE_SCROLL */

/*
 * Move the cursor to a given position, clipping at boundaries. We
 * may or may not want to clip at the scroll margin: marg_clip is 0
 * not to, 1 to disallow _passing_ the margins, and 2 to disallow
 * even _being_ outside the margins.
 */
static void move(Terminal *term, int x, int y, int marg_clip)
{
    if (x < 0)
        x = 0;
    if (x >= term->cols)
        x = term->cols - 1;
    if (marg_clip) {
        if ((term->curs.y >= term->marg_t || marg_clip == 2) &&
            y < term->marg_t)
            y = term->marg_t;
        if ((term->curs.y <= term->marg_b || marg_clip == 2) &&
            y > term->marg_b)
            y = term->marg_b;
    }
    if (y < 0)
        y = 0;
    if (y >= term->rows)
        y = term->rows - 1;
    term->curs.x = x;
    term->curs.y = y;
    fix_cpos;
    term->wrapnext = FALSE;
}

/*
 * Save or restore the cursor and SGR mode.
 */
static void save_cursor(Terminal *term, int save)
{
    if (save) {
        term->savecurs = term->curs;
        term->save_attr = term->curr_attr;
        term->save_cset = term->cset;
        term->save_utf = term->utf;
        term->save_wnext = term->wrapnext;
        term->save_csattr = term->cset_attr[term->cset];
        term->save_sco_acs = term->sco_acs;
    } else {
        term->curs = term->savecurs;
        /* Make sure the window hasn't shrunk since the save */
        if (term->curs.x >= term->cols)
            term->curs.x = term->cols - 1;
        if (term->curs.y >= term->rows)
            term->curs.y = term->rows - 1;

        term->curr_attr = term->save_attr;
        term->cset = term->save_cset;
        term->utf = term->save_utf;
        term->wrapnext = term->save_wnext;
        /*
         * wrapnext might reset to False if the x position is no
         * longer at the rightmost edge.
         */
        if (term->wrapnext && term->curs.x < term->cols-1)
            term->wrapnext = FALSE;
        term->cset_attr[term->cset] = term->save_csattr;
        term->sco_acs = term->save_sco_acs;
        fix_cpos;
        if (term->use_bce)
            term->erase_char = (' ' | ATTR_ASCII |
                                (term->curr_attr &
                                 (ATTR_FGMASK | ATTR_BGMASK)));
    }
}

/*
 * This function is called before doing _anything_ which affects
 * only part of a line of text. It is used to mark the boundary
 * between two character positions, and it indicates that some sort
 * of effect is going to happen on only one side of that boundary.
 * 
 * The effect of this function is to check whether a CJK
 * double-width character is straddling the boundary, and to remove
 * it and replace it with two spaces if so. (Of course, one or
 * other of those spaces is then likely to be replaced with
 * something else again, as a result of whatever happens next.)
 * 
 * Also, if the boundary is at the right-hand _edge_ of the screen,
 * it implies something deliberate is being done to the rightmost
 * column position; hence we must clear LATTR_WRAPPED2.
 * 
 * The input to the function is the coordinates of the _second_
 * character of the pair.
 */
static void check_boundary(Terminal *term, int x, int y)
{
    unsigned long *ldata;

    /* Validate input coordinates, just in case. */
    if (x == 0 || x > term->cols)
        return;

    ldata = lineptr(y);
    if (x == term->cols) {
        ldata[x] &= ~LATTR_WRAPPED2;
    } else {
        if ((ldata[x] & (CHAR_MASK | CSET_MASK)) == UCSWIDE) {
            ldata[x-1] = ldata[x] =
                (ldata[x-1] &~ (CHAR_MASK | CSET_MASK)) | ATTR_ASCII | ' ';
        }
    }
}

/*
 * Erase a large portion of the screen: the whole screen, or the
 * whole line, or parts thereof.
 */
static void erase_lots(Terminal *term,
                       int line_only, int from_begin, int to_end)
{
    pos start, end;
    int erase_lattr;
    unsigned long *ldata;

    if (line_only) {
        start.y = term->curs.y;
        start.x = 0;
        end.y = term->curs.y + 1;
        end.x = 0;
        erase_lattr = FALSE;
    } else {
        start.y = 0;
        start.x = 0;
        end.y = term->rows;
        end.x = 0;
        erase_lattr = TRUE;
    }
    if (!from_begin) {
        start = term->curs;
    }
    if (!to_end) {
        end = term->curs;
        incpos(end);
    }
    if (!from_begin || !to_end)
        check_boundary(term, term->curs.x, term->curs.y);
    check_selection(term, start, end);

    /* Clear screen also forces a full window redraw, just in case. */
    if (start.y == 0 && start.x == 0 && end.y == term->rows)
        term_invalidate(term);

    ldata = lineptr(start.y);
    while (poslt(start, end)) {
        if (start.x == term->cols && !erase_lattr)
            ldata[start.x] &= ~(LATTR_WRAPPED | LATTR_WRAPPED2);
        else
            ldata[start.x] = term->erase_char;
        if (incpos(start) && start.y < term->rows)
            ldata = lineptr(start.y);
    }
}

/*
 * Insert or delete characters within the current line. n is +ve if
 * insertion is desired, and -ve for deletion.
 */
static void insch(Terminal *term, int n)
{
    int dir = (n < 0 ? -1 : +1);
    int m;
    pos cursplus;
    unsigned long *ldata;

    n = (n < 0 ? -n : n);
    if (n > term->cols - term->curs.x)
        n = term->cols - term->curs.x;
    m = term->cols - term->curs.x - n;
    cursplus.y = term->curs.y;
    cursplus.x = term->curs.x + n;
    check_selection(term, term->curs, cursplus);
    check_boundary(term, term->curs.x, term->curs.y);
    if (dir < 0)
        check_boundary(term, term->curs.x + n, term->curs.y);
    ldata = lineptr(term->curs.y);
    if (dir < 0) {
        memmove(ldata + term->curs.x, ldata + term->curs.x + n, m * TSIZE);
        while (n--)
            ldata[term->curs.x + m++] = term->erase_char;
    } else {
        memmove(ldata + term->curs.x + n, ldata + term->curs.x, m * TSIZE);
        while (n--)
            ldata[term->curs.x + n] = term->erase_char;
    }
}

/*
 * Toggle terminal mode `mode' to state `state'. (`query' indicates
 * whether the mode is a DEC private one or a normal one.)
 */
static void toggle_mode(Terminal *term, int mode, int query, int state)
{
    unsigned long ticks;

    if (query)
        switch (mode) {
          case 1:                      /* application cursor keys */
            term->app_cursor_keys = state;
            break;
          case 2:                      /* VT52 mode */
            term->vt52_mode = !state;
            if (term->vt52_mode) {
                term->blink_is_real = FALSE;
                term->vt52_bold = FALSE;
            } else {
                term->blink_is_real = term->cfg->blinktext;
            }
            break;
          case 3:                      /* 80/132 columns */
            deselect(term);
            if (!term->cfg->no_remote_resize)
                request_resize(term->frontend, state ? 132 : 80, term->rows);
            term->reset_132 = state;
            break;
          case 5:                      /* reverse video */
            /*
             * Toggle reverse video. If we receive an OFF within the
             * visual bell timeout period after an ON, we trigger an
             * effective visual bell, so that ESC[?5hESC[?5l will
             * always be an actually _visible_ visual bell.
             */
            ticks = GETTICKCOUNT();
            /* turn off a previous vbell to avoid inconsistencies */
            if (ticks - term->vbell_startpoint >= VBELL_TIMEOUT)
                term->in_vbell = FALSE;
            if (term->rvideo && !state &&    /* we're turning it off... */
                (ticks - term->rvbell_startpoint) < VBELL_TIMEOUT) {/*...soon*/
                /* If there's no vbell timeout already, or this one lasts
                 * longer, replace vbell_timeout with ours. */
                if (!term->in_vbell ||
                    (term->rvbell_startpoint - term->vbell_startpoint <
                     VBELL_TIMEOUT))
                    term->vbell_startpoint = term->rvbell_startpoint;
                term->in_vbell = TRUE; /* may clear rvideo but set in_vbell */
            } else if (!term->rvideo && state) {
                /* This is an ON, so we notice the time and save it. */
                term->rvbell_startpoint = ticks;
            }
            term->rvideo = state;
            term->seen_disp_event = TRUE;
            if (state)
                term_update(term);
            break;
          case 6:                      /* DEC origin mode */
            term->dec_om = state;
            break;
          case 7:                      /* auto wrap */
            term->wrap = state;
            break;
          case 8:                      /* auto key repeat */
            term->repeat_off = !state;
            break;
          case 10:                     /* set local edit mode */
            term->term_editing = state;
            if (term->ldisc)           /* cause ldisc to notice changes */
                ldisc_send(term->ldisc, NULL, 0, 0);
            break;
          case 25:                     /* enable/disable cursor */
            compatibility2(OTHER, VT220);
            term->cursor_on = state;
            term->seen_disp_event = TRUE;
            break;
          case 47:                     /* alternate screen */
            compatibility(OTHER);
            deselect(term);
            swap_screen(term, term->cfg->no_alt_screen ? 0 : state, FALSE, FALSE);
            term->disptop = 0;
            break;
          case 1000:                   /* xterm mouse 1 */
            term->xterm_mouse = state ? 1 : 0;
            set_raw_mouse_mode(term->frontend, state);
            break;
          case 1002:                   /* xterm mouse 2 */
            term->xterm_mouse = state ? 2 : 0;
            set_raw_mouse_mode(term->frontend, state);
            break;
          case 1047:                   /* alternate screen */
            compatibility(OTHER);
            deselect(term);
            swap_screen(term, term->cfg->no_alt_screen ? 0 : state, TRUE, TRUE);
            term->disptop = 0;
            break;
          case 1048:                   /* save/restore cursor */
            save_cursor(term, state);
            if (!state) term->seen_disp_event = TRUE;
            break;
          case 1049:                   /* cursor & alternate screen */
            if (state)
                save_cursor(term, state);
            if (!state) term->seen_disp_event = TRUE;
            compatibility(OTHER);
            deselect(term);
            swap_screen(term, term->cfg->no_alt_screen ? 0 : state, TRUE, FALSE);
            if (!state)
                save_cursor(term, state);
            term->disptop = 0;
            break;
    } else
        switch (mode) {
          case 4:                      /* set insert mode */
            compatibility(VT102);
            term->insert = state;
            break;
          case 12:                     /* set echo mode */
            term->term_echoing = !state;
            if (term->ldisc)           /* cause ldisc to notice changes */
                ldisc_send(term->ldisc, NULL, 0, 0);
            break;
          case 20:                     /* Return sends ... */
            term->cr_lf_return = state;
            break;
          case 34:                     /* Make cursor BIG */
            compatibility2(OTHER, VT220);
            term->big_cursor = !state;
        }
}

/*
 * Process an OSC sequence: set window title or icon name.
 */
static void do_osc(Terminal *term)
{
    if (term->osc_w) {
        while (term->osc_strlen--)
            term->wordness[(unsigned char)
                term->osc_string[term->osc_strlen]] = term->esc_args[0];
    } else {
        term->osc_string[term->osc_strlen] = '\0';
        switch (term->esc_args[0]) {
          case 0:
          case 1:
            if (!term->cfg->no_remote_wintitle)
                set_icon(term->frontend, term->osc_string);
            if (term->esc_args[0] == 1)
                break;
            /* fall through: parameter 0 means set both */
          case 2:
          case 21:
            if (!term->cfg->no_remote_wintitle)
                set_title(term->frontend, term->osc_string);
            break;
        }
    }
}

/*
 * ANSI printing routines.
 */
static void term_print_setup(Terminal *term)
{
    bufchain_clear(&term->printer_buf);
    term->print_job = printer_start_job(term->cfg->printer);
}
static void term_print_flush(Terminal *term)
{
    void *data;
    int len;
    int size;
    while ((size = bufchain_size(&term->printer_buf)) > 5) {
        bufchain_prefix(&term->printer_buf, &data, &len);
        if (len > size-5)
            len = size-5;
        printer_job_data(term->print_job, data, len);
        bufchain_consume(&term->printer_buf, len);
    }
}
static void term_print_finish(Terminal *term)
{
    void *data;
    int len, size;
    char c;

    if (!term->printing && !term->only_printing)
        return;                        /* we need do nothing */

    term_print_flush(term);
    while ((size = bufchain_size(&term->printer_buf)) > 0) {
        bufchain_prefix(&term->printer_buf, &data, &len);
        c = *(char *)data;
        if (c == '\033' || c == '\233') {
            bufchain_consume(&term->printer_buf, size);
            break;
        } else {
            printer_job_data(term->print_job, &c, 1);
            bufchain_consume(&term->printer_buf, 1);
        }
    }
    printer_finish_job(term->print_job);
    term->print_job = NULL;
    term->printing = term->only_printing = FALSE;
}

/*
 * Remove everything currently in `inbuf' and stick it up on the
 * in-memory display. There's a big state machine in here to
 * process escape sequences...
 */
void term_out(Terminal *term)
{
    int c, unget;
    unsigned char localbuf[256], *chars;
    int nchars = 0;

    unget = -1;

    chars = NULL;                      /* placate compiler warnings */
    while (nchars > 0 || bufchain_size(&term->inbuf) > 0) {
        if (unget == -1) {
            if (nchars == 0) {
                void *ret;
                bufchain_prefix(&term->inbuf, &ret, &nchars);
                if (nchars > sizeof(localbuf))
                    nchars = sizeof(localbuf);
                memcpy(localbuf, ret, nchars);
                bufchain_consume(&term->inbuf, nchars);
                chars = localbuf;
                assert(chars != NULL);
            }
            c = *chars++;
            nchars--;

            /*
             * Optionally log the session traffic to a file. Useful for
             * debugging and possibly also useful for actual logging.
             */
            if (term->cfg->logtype == LGTYP_DEBUG && term->logctx)
                logtraffic(term->logctx, (unsigned char) c, LGTYP_DEBUG);
        } else {
            c = unget;
            unget = -1;
        }

        /* Note only VT220+ are 8-bit VT102 is seven bit, it shouldn't even
         * be able to display 8-bit characters, but I'll let that go 'cause
         * of i18n.
         */

        /*
         * If we're printing, add the character to the printer
         * buffer.
         */
        if (term->printing) {
            bufchain_add(&term->printer_buf, &c, 1);

            /*
             * If we're in print-only mode, we use a much simpler
             * state machine designed only to recognise the ESC[4i
             * termination sequence.
             */
            if (term->only_printing) {
                if (c == '\033')
                    term->print_state = 1;
                else if (c == (unsigned char)'\233')
                    term->print_state = 2;
                else if (c == '[' && term->print_state == 1)
                    term->print_state = 2;
                else if (c == '4' && term->print_state == 2)
                    term->print_state = 3;
                else if (c == 'i' && term->print_state == 3)
                    term->print_state = 4;
                else
                    term->print_state = 0;
                if (term->print_state == 4) {
                    term_print_finish(term);
                }
                continue;
            }
        }

        /* First see about all those translations. */
        if (term->termstate == TOPLEVEL) {
            if (in_utf(term))
                switch (term->utf_state) {
                  case 0:
                    if (c < 0x80) {
                        /* UTF-8 must be stateless so we ignore iso2022. */
                        if (unitab_ctrl[c] != 0xFF) 
                             c = unitab_ctrl[c];
                        else c = ((unsigned char)c) | ATTR_ASCII;
                        break;
                    } else if ((c & 0xe0) == 0xc0) {
                        term->utf_size = term->utf_state = 1;
                        term->utf_char = (c & 0x1f);
                    } else if ((c & 0xf0) == 0xe0) {
                        term->utf_size = term->utf_state = 2;
                        term->utf_char = (c & 0x0f);
                    } else if ((c & 0xf8) == 0xf0) {
                        term->utf_size = term->utf_state = 3;
                        term->utf_char = (c & 0x07);
                    } else if ((c & 0xfc) == 0xf8) {
                        term->utf_size = term->utf_state = 4;
                        term->utf_char = (c & 0x03);
                    } else if ((c & 0xfe) == 0xfc) {
                        term->utf_size = term->utf_state = 5;
                        term->utf_char = (c & 0x01);
                    } else {
                        c = UCSERR;
                        break;
                    }
                    continue;
                  case 1:
                  case 2:
                  case 3:
                  case 4:
                  case 5:
                    if ((c & 0xC0) != 0x80) {
                        unget = c;
                        c = UCSERR;
                        term->utf_state = 0;
                        break;
                    }
                    term->utf_char = (term->utf_char << 6) | (c & 0x3f);
                    if (--term->utf_state)
                        continue;

                    c = term->utf_char;

                    /* Is somebody trying to be evil! */
                    if (c < 0x80 ||
                        (c < 0x800 && term->utf_size >= 2) ||
                        (c < 0x10000 && term->utf_size >= 3) ||
                        (c < 0x200000 && term->utf_size >= 4) ||
                        (c < 0x4000000 && term->utf_size >= 5))
                        c = UCSERR;

                    /* Unicode line separator and paragraph separator are CR-LF */
                    if (c == 0x2028 || c == 0x2029)
                        c = 0x85;

                    /* High controls are probably a Baaad idea too. */
                    if (c < 0xA0)
                        c = 0xFFFD;

                    /* The UTF-16 surrogates are not nice either. */
                    /*       The standard give the option of decoding these: 
                     *       I don't want to! */
                    if (c >= 0xD800 && c < 0xE000)
                        c = UCSERR;

                    /* ISO 10646 characters now limited to UTF-16 range. */
                    if (c > 0x10FFFF)
                        c = UCSERR;

                    /* This is currently a TagPhobic application.. */
                    if (c >= 0xE0000 && c <= 0xE007F)
                        continue;

                    /* U+FEFF is best seen as a null. */
                    if (c == 0xFEFF)
                        continue;
                    /* But U+FFFE is an error. */
                    if (c == 0xFFFE || c == 0xFFFF)
                        c = UCSERR;

                    /* Oops this is a 16bit implementation */
                    if (c >= 0x10000)
                        c = 0xFFFD;
                    break;
            }
            /* Are we in the nasty ACS mode? Note: no sco in utf mode. */
            else if(term->sco_acs && 
                    (c!='\033' && c!='\012' && c!='\015' && c!='\b'))
            {
               if (term->sco_acs == 2) c |= 0x80;
               c |= ATTR_SCOACS;
            } else {
                switch (term->cset_attr[term->cset]) {
                    /* 
                     * Linedraw characters are different from 'ESC ( B'
                     * only for a small range. For ones outside that
                     * range, make sure we use the same font as well as
                     * the same encoding.
                     */
                  case ATTR_LINEDRW:
                    if (unitab_ctrl[c] != 0xFF)
                        c = unitab_ctrl[c];
                    else
                        c = ((unsigned char) c) | ATTR_LINEDRW;
                    break;

                  case ATTR_GBCHR:
                    /* If UK-ASCII, make the '#' a LineDraw Pound */
                    if (c == '#') {
                        c = '}' | ATTR_LINEDRW;
                        break;
                    }
                  /*FALLTHROUGH*/ case ATTR_ASCII:
                    if (unitab_ctrl[c] != 0xFF)
                        c = unitab_ctrl[c];
                    else
                        c = ((unsigned char) c) | ATTR_ASCII;
                    break;
                case ATTR_SCOACS:
                    if (c>=' ') c = ((unsigned char)c) | ATTR_SCOACS;
                    break;
                }
            }
        }

        /* How about C1 controls ? */
        if ((c & -32) == 0x80 && term->termstate < DO_CTRLS &&
            !term->vt52_mode && has_compat(VT220)) {
            term->termstate = SEEN_ESC;
            term->esc_query = FALSE;
            c = '@' + (c & 0x1F);
        }

        /* Or the GL control. */
        if (c == '\177' && term->termstate < DO_CTRLS && has_compat(OTHER)) {
            if (term->curs.x && !term->wrapnext)
                term->curs.x--;
            term->wrapnext = FALSE;
            fix_cpos;
            if (!term->cfg->no_dbackspace)    /* destructive bksp might be disabled */
                *term->cpos = (' ' | term->curr_attr | ATTR_ASCII);
        } else
            /* Or normal C0 controls. */
        if ((c & -32) == 0 && term->termstate < DO_CTRLS) {
            switch (c) {
              case '\005':             /* terminal type query */
                /* Strictly speaking this is VT100 but a VT100 defaults to
                 * no response. Other terminals respond at their option.
                 *
                 * Don't put a CR in the default string as this tends to
                 * upset some weird software.
                 *
                 * An xterm returns "xterm" (5 characters)
                 */
                compatibility(ANSIMIN);
                if (term->ldisc) {
                    char abuf[256], *s, *d;
                    int state = 0;
                    for (s = term->cfg->answerback, d = abuf; *s; s++) {
                        if (state) {
                            if (*s >= 'a' && *s <= 'z')
                                *d++ = (*s - ('a' - 1));
                            else if ((*s >= '@' && *s <= '_') ||
                                     *s == '?' || (*s & 0x80))
                                *d++ = ('@' ^ *s);
                            else if (*s == '~')
                                *d++ = '^';
                            state = 0;
                        } else if (*s == '^') {
                            state = 1;
                        } else
                            *d++ = *s;
                    }
                    lpage_send(term->ldisc, DEFAULT_CODEPAGE,
                               abuf, d - abuf, 0);
                }
                break;
              case '\007':
                {
                    struct beeptime *newbeep;
                    unsigned long ticks;

                    ticks = GETTICKCOUNT();

                    if (!term->beep_overloaded) {
                        newbeep = smalloc(sizeof(struct beeptime));
                        newbeep->ticks = ticks;
                        newbeep->next = NULL;
                        if (!term->beephead)
                            term->beephead = newbeep;
                        else
                            term->beeptail->next = newbeep;
                        term->beeptail = newbeep;
                        term->nbeeps++;
                    }

                    /*
                     * Throw out any beeps that happened more than
                     * t seconds ago.
                     */
                    while (term->beephead &&
                           term->beephead->ticks < ticks - term->cfg->bellovl_t) {
                        struct beeptime *tmp = term->beephead;
                        term->beephead = tmp->next;
                        sfree(tmp);
                        if (!term->beephead)
                            term->beeptail = NULL;
                        term->nbeeps--;
                    }

                    if (term->cfg->bellovl && term->beep_overloaded &&
                        ticks - term->lastbeep >= (unsigned)term->cfg->bellovl_s) {
                        /*
                         * If we're currently overloaded and the
                         * last beep was more than s seconds ago,
                         * leave overload mode.
                         */
                        term->beep_overloaded = FALSE;
                    } else if (term->cfg->bellovl && !term->beep_overloaded &&
                               term->nbeeps >= term->cfg->bellovl_n) {
                        /*
                         * Now, if we have n or more beeps
                         * remaining in the queue, go into overload
                         * mode.
                         */
                        term->beep_overloaded = TRUE;
                    }
                    term->lastbeep = ticks;

                    /*
                     * Perform an actual beep if we're not overloaded.
                     */
                    if (!term->cfg->bellovl || !term->beep_overloaded) {
                        beep(term->frontend, term->cfg->beep);
                        if (term->cfg->beep == BELL_VISUAL) {
                            term->in_vbell = TRUE;
                            term->vbell_startpoint = ticks;
                            term_update(term);
                        }
                    }
                    term->disptop = 0;
                }
                break;
              case '\b':
                if (term->curs.x == 0 &&
                    (term->curs.y == 0 || term->wrap == 0))
                    /* do nothing */ ;
                else if (term->curs.x == 0 && term->curs.y > 0)
                    term->curs.x = term->cols - 1, term->curs.y--;
                else if (term->wrapnext)
                    term->wrapnext = FALSE;
                else
                    term->curs.x--;
                fix_cpos;
                term->seen_disp_event = TRUE;
                break;
              case '\016':
                compatibility(VT100);
                term->cset = 1;
                break;
              case '\017':
                compatibility(VT100);
                term->cset = 0;
                break;
              case '\033':
                if (term->vt52_mode)
                    term->termstate = VT52_ESC;
                else {
                    compatibility(ANSIMIN);
                    term->termstate = SEEN_ESC;
                    term->esc_query = FALSE;
                }
                break;
              case '\015':
                term->curs.x = 0;
                term->wrapnext = FALSE;
                fix_cpos;
                term->seen_disp_event = TRUE;
                term->paste_hold = 0;
                if (term->logctx)
                    logtraffic(term->logctx, (unsigned char) c, LGTYP_ASCII);
                break;
              case '\014':
                if (has_compat(SCOANSI)) {
                    move(term, 0, 0, 0);
                    erase_lots(term, FALSE, FALSE, TRUE);
                    term->disptop = 0;
                    term->wrapnext = FALSE;
                    term->seen_disp_event = 1;
                    break;
                }
              case '\013':
                compatibility(VT100);
              case '\012':
                if (term->curs.y == term->marg_b)
                    scroll(term, term->marg_t, term->marg_b, 1, TRUE);
                else if (term->curs.y < term->rows - 1)
                    term->curs.y++;
                if (term->cfg->lfhascr)
                    term->curs.x = 0;
                fix_cpos;
                term->wrapnext = FALSE;
                term->seen_disp_event = 1;
                term->paste_hold = 0;
                if (term->logctx)
                    logtraffic(term->logctx, (unsigned char) c, LGTYP_ASCII);
                break;
              case '\t':
                {
                    pos old_curs = term->curs;
                    unsigned long *ldata = lineptr(term->curs.y);

                    do {
                        term->curs.x++;
                    } while (term->curs.x < term->cols - 1 &&
                             !term->tabs[term->curs.x]);

                    if ((ldata[term->cols] & LATTR_MODE) != LATTR_NORM) {
                        if (term->curs.x >= term->cols / 2)
                            term->curs.x = term->cols / 2 - 1;
                    } else {
                        if (term->curs.x >= term->cols)
                            term->curs.x = term->cols - 1;
                    }

                    fix_cpos;
                    check_selection(term, old_curs, term->curs);
                }
                term->seen_disp_event = TRUE;
                break;
            }
        } else
            switch (term->termstate) {
              case TOPLEVEL:
                /* Only graphic characters get this far;
                 * ctrls are stripped above */
                if (term->wrapnext && term->wrap) {
                    term->cpos[1] |= LATTR_WRAPPED;
                    if (term->curs.y == term->marg_b)
                        scroll(term, term->marg_t, term->marg_b, 1, TRUE);
                    else if (term->curs.y < term->rows - 1)
                        term->curs.y++;
                    term->curs.x = 0;
                    fix_cpos;
                    term->wrapnext = FALSE;
                }
                if (term->insert)
                    insch(term, 1);
                if (term->selstate != NO_SELECTION) {
                    pos cursplus = term->curs;
                    incpos(cursplus);
                    check_selection(term, term->curs, cursplus);
                }
                if (((c & CSET_MASK) == ATTR_ASCII || (c & CSET_MASK) == 0) &&
                    term->logctx)
                    logtraffic(term->logctx, (unsigned char) c, LGTYP_ASCII);
                {
                    int width = 0;
                    if (DIRECT_CHAR(c))
                        width = 1;
                    if (!width)
                        width = wcwidth((wchar_t) c);
                    switch (width) {
                      case 2:
                        /*
                         * If we're about to display a double-width
                         * character starting in the rightmost
                         * column, then we do something special
                         * instead. We must print a space in the
                         * last column of the screen, then wrap;
                         * and we also set LATTR_WRAPPED2 which
                         * instructs subsequent cut-and-pasting not
                         * only to splice this line to the one
                         * after it, but to ignore the space in the
                         * last character position as well.
                         * (Because what was actually output to the
                         * terminal was presumably just a sequence
                         * of CJK characters, and we don't want a
                         * space to be pasted in the middle of
                         * those just because they had the
                         * misfortune to start in the wrong parity
                         * column. xterm concurs.)
                         */
                        check_boundary(term, term->curs.x, term->curs.y);
                        check_boundary(term, term->curs.x+2, term->curs.y);
                        if (term->curs.x == term->cols-1) {
                            *term->cpos++ = ATTR_ASCII | ' ' | term->curr_attr;
                            *term->cpos |= LATTR_WRAPPED | LATTR_WRAPPED2;
                            if (term->curs.y == term->marg_b)
                                scroll(term, term->marg_t, term->marg_b,
                                       1, TRUE);
                            else if (term->curs.y < term->rows - 1)
                                term->curs.y++;
                            term->curs.x = 0;
                            fix_cpos;
                            /* Now we must check_boundary again, of course. */
                            check_boundary(term, term->curs.x, term->curs.y);
                            check_boundary(term, term->curs.x+2, term->curs.y);
                        }
                        *term->cpos++ = c | term->curr_attr;
                        *term->cpos++ = UCSWIDE | term->curr_attr;
                        term->curs.x++;
                        break;
                      case 1:
                        check_boundary(term, term->curs.x, term->curs.y);
                        check_boundary(term, term->curs.x+1, term->curs.y);
                        *term->cpos++ = c | term->curr_attr;
                        break;
                      default:
                        continue;
                    }
                }
                term->curs.x++;
                if (term->curs.x == term->cols) {
                    term->cpos--;
                    term->curs.x--;
                    term->wrapnext = TRUE;
                    if (term->wrap && term->vt52_mode) {
                        term->cpos[1] |= LATTR_WRAPPED;
                        if (term->curs.y == term->marg_b)
                            scroll(term, term->marg_t, term->marg_b, 1, TRUE);
                        else if (term->curs.y < term->rows - 1)
                            term->curs.y++;
                        term->curs.x = 0;
                        fix_cpos;
                        term->wrapnext = FALSE;
                    }
                }
                term->seen_disp_event = 1;
                break;

              case OSC_MAYBE_ST:
                /*
                 * This state is virtually identical to SEEN_ESC, with the
                 * exception that we have an OSC sequence in the pipeline,
                 * and _if_ we see a backslash, we process it.
                 */
                if (c == '\\') {
                    do_osc(term);
                    term->termstate = TOPLEVEL;
                    break;
                }
                /* else fall through */
              case SEEN_ESC:
                if (c >= ' ' && c <= '/') {
                    if (term->esc_query)
                        term->esc_query = -1;
                    else
                        term->esc_query = c;
                    break;
                }
                term->termstate = TOPLEVEL;
                switch (ANSI(c, term->esc_query)) {
                  case '[':            /* enter CSI mode */
                    term->termstate = SEEN_CSI;
                    term->esc_nargs = 1;
                    term->esc_args[0] = ARG_DEFAULT;
                    term->esc_query = FALSE;
                    break;
                  case ']':            /* xterm escape sequences */
                    /* Compatibility is nasty here, xterm, linux, decterm yuk! */
                    compatibility(OTHER);
                    term->termstate = SEEN_OSC;
                    term->esc_args[0] = 0;
                    break;
                  case '7':            /* save cursor */
                    compatibility(VT100);
                    save_cursor(term, TRUE);
                    break;
                  case '8':            /* restore cursor */
                    compatibility(VT100);
                    save_cursor(term, FALSE);
                    term->seen_disp_event = TRUE;
                    break;
                  case '=':
                    compatibility(VT100);
                    term->app_keypad_keys = TRUE;
                    break;
                  case '>':
                    compatibility(VT100);
                    term->app_keypad_keys = FALSE;
                    break;
                  case 'D':            /* exactly equivalent to LF */
                    compatibility(VT100);
                    if (term->curs.y == term->marg_b)
                        scroll(term, term->marg_t, term->marg_b, 1, TRUE);
                    else if (term->curs.y < term->rows - 1)
                        term->curs.y++;
                    fix_cpos;
                    term->wrapnext = FALSE;
                    term->seen_disp_event = TRUE;
                    break;
                  case 'E':            /* exactly equivalent to CR-LF */
                    compatibility(VT100);
                    term->curs.x = 0;
                    if (term->curs.y == term->marg_b)
                        scroll(term, term->marg_t, term->marg_b, 1, TRUE);
                    else if (term->curs.y < term->rows - 1)
                        term->curs.y++;
                    fix_cpos;
                    term->wrapnext = FALSE;
                    term->seen_disp_event = TRUE;
                    break;
                  case 'M':            /* reverse index - backwards LF */
                    compatibility(VT100);
                    if (term->curs.y == term->marg_t)
                        scroll(term, term->marg_t, term->marg_b, -1, TRUE);
                    else if (term->curs.y > 0)
                        term->curs.y--;
                    fix_cpos;
                    term->wrapnext = FALSE;
                    term->seen_disp_event = TRUE;
                    break;
                  case 'Z':            /* terminal type query */
                    compatibility(VT100);
                    if (term->ldisc)
                        ldisc_send(term->ldisc, term->id_string,
                                   strlen(term->id_string), 0);
                    break;
                  case 'c':            /* restore power-on settings */
                    compatibility(VT100);
                    power_on(term);
                    if (term->ldisc)   /* cause ldisc to notice changes */
                        ldisc_send(term->ldisc, NULL, 0, 0);
                    if (term->reset_132) {
                        if (!term->cfg->no_remote_resize)
                            request_resize(term->frontend, 80, term->rows);
                        term->reset_132 = 0;
                    }
                    fix_cpos;
                    term->disptop = 0;
                    term->seen_disp_event = TRUE;
                    break;
                  case 'H':            /* set a tab */
                    compatibility(VT100);
                    term->tabs[term->curs.x] = TRUE;
                    break;

                  case ANSI('8', '#'):  /* ESC # 8 fills screen with Es :-) */
                    compatibility(VT100);
                    {
                        unsigned long *ldata;
                        int i, j;
                        pos scrtop, scrbot;

                        for (i = 0; i < term->rows; i++) {
                            ldata = lineptr(i);
                            for (j = 0; j < term->cols; j++)
                                ldata[j] = ATTR_DEFAULT | 'E';
                            ldata[term->cols] = 0;
                        }
                        term->disptop = 0;
                        term->seen_disp_event = TRUE;
                        scrtop.x = scrtop.y = 0;
                        scrbot.x = 0;
                        scrbot.y = term->rows;
                        check_selection(term, scrtop, scrbot);
                    }
                    break;

                  case ANSI('3', '#'):
                  case ANSI('4', '#'):
                  case ANSI('5', '#'):
                  case ANSI('6', '#'):
                    compatibility(VT100);
                    {
                        unsigned long nlattr;
                        unsigned long *ldata;
                        switch (ANSI(c, term->esc_query)) {
                          case ANSI('3', '#'):
                            nlattr = LATTR_TOP;
                            break;
                          case ANSI('4', '#'):
                            nlattr = LATTR_BOT;
                            break;
                          case ANSI('5', '#'):
                            nlattr = LATTR_NORM;
                            break;
                          default: /* spiritually case ANSI('6', '#'): */
                            nlattr = LATTR_WIDE;
                            break;
                        }
                        ldata = lineptr(term->curs.y);
                        ldata[term->cols] &= ~LATTR_MODE;
                        ldata[term->cols] |= nlattr;
                    }
                    break;

                  case ANSI('A', '('):
                    compatibility(VT100);
                    if (!term->cfg->no_remote_charset)
                        term->cset_attr[0] = ATTR_GBCHR;
                    break;
                  case ANSI('B', '('):
                    compatibility(VT100);
                    if (!term->cfg->no_remote_charset)
                        term->cset_attr[0] = ATTR_ASCII;
                    break;
                  case ANSI('0', '('):
                    compatibility(VT100);
                    if (!term->cfg->no_remote_charset)
                        term->cset_attr[0] = ATTR_LINEDRW;
                    break;
                  case ANSI('U', '('): 
                    compatibility(OTHER);
                    if (!term->cfg->no_remote_charset)
                        term->cset_attr[0] = ATTR_SCOACS; 
                    break;

                  case ANSI('A', ')'):
                    compatibility(VT100);
                    if (!term->cfg->no_remote_charset)
                        term->cset_attr[1] = ATTR_GBCHR;
                    break;
                  case ANSI('B', ')'):
                    compatibility(VT100);
                    if (!term->cfg->no_remote_charset)
                        term->cset_attr[1] = ATTR_ASCII;
                    break;
                  case ANSI('0', ')'):
                    compatibility(VT100);
                    if (!term->cfg->no_remote_charset)
                        term->cset_attr[1] = ATTR_LINEDRW;
                    break;
                  case ANSI('U', ')'): 
                    compatibility(OTHER);
                    if (!term->cfg->no_remote_charset)
                        term->cset_attr[1] = ATTR_SCOACS; 
                    break;

                  case ANSI('8', '%'):  /* Old Linux code */
                  case ANSI('G', '%'):
                    compatibility(OTHER);
                    if (!term->cfg->no_remote_charset)
                        term->utf = 1;
                    break;
                  case ANSI('@', '%'):
                    compatibility(OTHER);
                    if (!term->cfg->no_remote_charset)
                        term->utf = 0;
                    break;
                }
                break;
              case SEEN_CSI:
                term->termstate = TOPLEVEL;  /* default */
                if (isdigit(c)) {
                    if (term->esc_nargs <= ARGS_MAX) {
                        if (term->esc_args[term->esc_nargs - 1] == ARG_DEFAULT)
                            term->esc_args[term->esc_nargs - 1] = 0;
                        term->esc_args[term->esc_nargs - 1] =
                            10 * term->esc_args[term->esc_nargs - 1] + c - '0';
                    }
                    term->termstate = SEEN_CSI;
                } else if (c == ';') {
                    if (++term->esc_nargs <= ARGS_MAX)
                        term->esc_args[term->esc_nargs - 1] = ARG_DEFAULT;
                    term->termstate = SEEN_CSI;
                } else if (c < '@') {
                    if (term->esc_query)
                        term->esc_query = -1;
                    else if (c == '?')
                        term->esc_query = TRUE;
                    else
                        term->esc_query = c;
                    term->termstate = SEEN_CSI;
                } else
                    switch (ANSI(c, term->esc_query)) {
                      case 'A':       /* move up N lines */
                        move(term, term->curs.x,
                             term->curs.y - def(term->esc_args[0], 1), 1);
                        term->seen_disp_event = TRUE;
                        break;
                      case 'e':       /* move down N lines */
                        compatibility(ANSI);
                        /* FALLTHROUGH */
                      case 'B':
                        move(term, term->curs.x,
                             term->curs.y + def(term->esc_args[0], 1), 1);
                        term->seen_disp_event = TRUE;
                        break;
                      case ANSI('c', '>'):      /* report xterm version */
                        compatibility(OTHER);
                        /* this reports xterm version 136 so that VIM can
                           use the drag messages from the mouse reporting */
                        if (term->ldisc)
                            ldisc_send(term->ldisc, "\033[>0;136;0c", 11, 0);
                        break;
                      case 'a':       /* move right N cols */
                        compatibility(ANSI);
                        /* FALLTHROUGH */
                      case 'C':
                        move(term, term->curs.x + def(term->esc_args[0], 1),
                             term->curs.y, 1);
                        term->seen_disp_event = TRUE;
                        break;
                      case 'D':       /* move left N cols */
                        move(term, term->curs.x - def(term->esc_args[0], 1),
                             term->curs.y, 1);
                        term->seen_disp_event = TRUE;
                        break;
                      case 'E':       /* move down N lines and CR */
                        compatibility(ANSI);
                        move(term, 0,
                             term->curs.y + def(term->esc_args[0], 1), 1);
                        term->seen_disp_event = TRUE;
                        break;
                      case 'F':       /* move up N lines and CR */
                        compatibility(ANSI);
                        move(term, 0,
                             term->curs.y - def(term->esc_args[0], 1), 1);
                        term->seen_disp_event = TRUE;
                        break;
                      case 'G':
                      case '`':       /* set horizontal posn */
                        compatibility(ANSI);
                        move(term, def(term->esc_args[0], 1) - 1,
                             term->curs.y, 0);
                        term->seen_disp_event = TRUE;
                        break;
                      case 'd':       /* set vertical posn */
                        compatibility(ANSI);
                        move(term, term->curs.x,
                             ((term->dec_om ? term->marg_t : 0) +
                              def(term->esc_args[0], 1) - 1),
                             (term->dec_om ? 2 : 0));
                        term->seen_disp_event = TRUE;
                        break;
                      case 'H':
                      case 'f':       /* set horz and vert posns at once */
                        if (term->esc_nargs < 2)
                            term->esc_args[1] = ARG_DEFAULT;
                        move(term, def(term->esc_args[1], 1) - 1,
                             ((term->dec_om ? term->marg_t : 0) +
                              def(term->esc_args[0], 1) - 1),
                             (term->dec_om ? 2 : 0));
                        term->seen_disp_event = TRUE;
                        break;
                      case 'J':       /* erase screen or parts of it */
                        {
                            unsigned int i = def(term->esc_args[0], 0) + 1;
                            if (i > 3)
                                i = 0;
                            erase_lots(term, FALSE, !!(i & 2), !!(i & 1));
                        }
                        term->disptop = 0;
                        term->seen_disp_event = TRUE;
                        break;
                      case 'K':       /* erase line or parts of it */
                        {
                            unsigned int i = def(term->esc_args[0], 0) + 1;
                            if (i > 3)
                                i = 0;
                            erase_lots(term, TRUE, !!(i & 2), !!(i & 1));
                        }
                        term->seen_disp_event = TRUE;
                        break;
                      case 'L':       /* insert lines */
                        compatibility(VT102);
                        if (term->curs.y <= term->marg_b)
                            scroll(term, term->curs.y, term->marg_b,
                                   -def(term->esc_args[0], 1), FALSE);
                        fix_cpos;
                        term->seen_disp_event = TRUE;
                        break;
                      case 'M':       /* delete lines */
                        compatibility(VT102);
                        if (term->curs.y <= term->marg_b)
                            scroll(term, term->curs.y, term->marg_b,
                                   def(term->esc_args[0], 1),
                                   TRUE);
                        fix_cpos;
                        term->seen_disp_event = TRUE;
                        break;
                      case '@':       /* insert chars */
                        /* XXX VTTEST says this is vt220, vt510 manual says vt102 */
                        compatibility(VT102);
                        insch(term, def(term->esc_args[0], 1));
                        term->seen_disp_event = TRUE;
                        break;
                      case 'P':       /* delete chars */
                        compatibility(VT102);
                        insch(term, -def(term->esc_args[0], 1));
                        term->seen_disp_event = TRUE;
                        break;
                      case 'c':       /* terminal type query */
                        compatibility(VT100);
                        /* This is the response for a VT102 */
                        if (term->ldisc)
                            ldisc_send(term->ldisc, term->id_string,
                                       strlen(term->id_string), 0);
                        break;
                      case 'n':       /* cursor position query */
                        if (term->ldisc) {
                            if (term->esc_args[0] == 6) {
                                char buf[32];
                                sprintf(buf, "\033[%d;%dR", term->curs.y + 1,
                                        term->curs.x + 1);
                                ldisc_send(term->ldisc, buf, strlen(buf), 0);
                            } else if (term->esc_args[0] == 5) {
                                ldisc_send(term->ldisc, "\033[0n", 4, 0);
                            }
                        }
                        break;
                      case 'h':       /* toggle modes to high */
                      case ANSI_QUE('h'):
                        compatibility(VT100);
                        {
                            int i;
                            for (i = 0; i < term->esc_nargs; i++)
                                toggle_mode(term, term->esc_args[i],
                                            term->esc_query, TRUE);
                        }
                        break;
                      case 'i':
                      case ANSI_QUE('i'):
                        compatibility(VT100);
                        {
                            if (term->esc_nargs != 1) break;
                            if (term->esc_args[0] == 5 && *term->cfg->printer) {
                                term->printing = TRUE;
                                term->only_printing = !term->esc_query;
                                term->print_state = 0;
                                term_print_setup(term);
                            } else if (term->esc_args[0] == 4 &&
                                       term->printing) {
                                term_print_finish(term);
                            }
                        }
                        break;                  
                      case 'l':       /* toggle modes to low */
                      case ANSI_QUE('l'):
                        compatibility(VT100);
                        {
                            int i;
                            for (i = 0; i < term->esc_nargs; i++)
                                toggle_mode(term, term->esc_args[i],
                                            term->esc_query, FALSE);
                        }
                        break;
                      case 'g':       /* clear tabs */
                        compatibility(VT100);
                        if (term->esc_nargs == 1) {
                            if (term->esc_args[0] == 0) {
                                term->tabs[term->curs.x] = FALSE;
                            } else if (term->esc_args[0] == 3) {
                                int i;
                                for (i = 0; i < term->cols; i++)
                                    term->tabs[i] = FALSE;
                            }
                        }
                        break;
                      case 'r':       /* set scroll margins */
                        compatibility(VT100);
                        if (term->esc_nargs <= 2) {
                            int top, bot;
                            top = def(term->esc_args[0], 1) - 1;
                            bot = (term->esc_nargs <= 1
                                   || term->esc_args[1] == 0 ?
                                   term->rows :
                                   def(term->esc_args[1], term->rows)) - 1;
                            if (bot >= term->rows)
                                bot = term->rows - 1;
                            /* VTTEST Bug 9 - if region is less than 2 lines
                             * don't change region.
                             */
                            if (bot - top > 0) {
                                term->marg_t = top;
                                term->marg_b = bot;
                                term->curs.x = 0;
                                /*
                                 * I used to think the cursor should be
                                 * placed at the top of the newly marginned
                                 * area. Apparently not: VMS TPU falls over
                                 * if so.
                                 *
                                 * Well actually it should for
                                 * Origin mode - RDB
                                 */
                                term->curs.y = (term->dec_om ?
                                                term->marg_t : 0);
                                fix_cpos;
                                term->seen_disp_event = TRUE;
                            }
                        }
                        break;
                      case 'm':       /* set graphics rendition */
                        {
                            /* 
                             * A VT100 without the AVO only had one
                             * attribute, either underline or
                             * reverse video depending on the
                             * cursor type, this was selected by
                             * CSI 7m.
                             *
                             * case 2:
                             *  This is sometimes DIM, eg on the
                             *  GIGI and Linux
                             * case 8:
                             *  This is sometimes INVIS various ANSI.
                             * case 21:
                             *  This like 22 disables BOLD, DIM and INVIS
                             *
                             * The ANSI colours appear on any
                             * terminal that has colour (obviously)
                             * but the interaction between sgr0 and
                             * the colours varies but is usually
                             * related to the background colour
                             * erase item. The interaction between
                             * colour attributes and the mono ones
                             * is also very implementation
                             * dependent.
                             *
                             * The 39 and 49 attributes are likely
                             * to be unimplemented.
                             */
                            int i;
                            for (i = 0; i < term->esc_nargs; i++) {
                                switch (def(term->esc_args[i], 0)) {
                                  case 0:       /* restore defaults */
                                    term->curr_attr = ATTR_DEFAULT;
                                    break;
                                  case 1:       /* enable bold */
                                    compatibility(VT100AVO);
                                    term->curr_attr |= ATTR_BOLD;
                                    break;
                                  case 21:      /* (enable double underline) */
                                    compatibility(OTHER);
                                  case 4:       /* enable underline */
                                    compatibility(VT100AVO);
                                    term->curr_attr |= ATTR_UNDER;
                                    break;
                                  case 5:       /* enable blink */
                                    compatibility(VT100AVO);
                                    term->curr_attr |= ATTR_BLINK;
                                    break;
                                  case 7:       /* enable reverse video */
                                    term->curr_attr |= ATTR_REVERSE;
                                    break;
                                  case 10:      /* SCO acs off */
                                    compatibility(SCOANSI);
                                    if (term->cfg->no_remote_charset) break;
                                    term->sco_acs = 0; break;
                                  case 11:      /* SCO acs on */
                                    compatibility(SCOANSI);
                                    if (term->cfg->no_remote_charset) break;
                                    term->sco_acs = 1; break;
                                  case 12:      /* SCO acs on, |0x80 */
                                    compatibility(SCOANSI);
                                    if (term->cfg->no_remote_charset) break;
                                    term->sco_acs = 2; break;
                                  case 22:      /* disable bold */
                                    compatibility2(OTHER, VT220);
                                    term->curr_attr &= ~ATTR_BOLD;
                                    break;
                                  case 24:      /* disable underline */
                                    compatibility2(OTHER, VT220);
                                    term->curr_attr &= ~ATTR_UNDER;
                                    break;
                                  case 25:      /* disable blink */
                                    compatibility2(OTHER, VT220);
                                    term->curr_attr &= ~ATTR_BLINK;
                                    break;
                                  case 27:      /* disable reverse video */
                                    compatibility2(OTHER, VT220);
                                    term->curr_attr &= ~ATTR_REVERSE;
                                    break;
                                  case 30:
                                  case 31:
                                  case 32:
                                  case 33:
                                  case 34:
                                  case 35:
                                  case 36:
                                  case 37:
                                    /* foreground */
                                    term->curr_attr &= ~ATTR_FGMASK;
                                    term->curr_attr |=
                                        (term->esc_args[i] - 30)<<ATTR_FGSHIFT;
                                    break;
                                  case 39:      /* default-foreground */
                                    term->curr_attr &= ~ATTR_FGMASK;
                                    term->curr_attr |= ATTR_DEFFG;
                                    break;
                                  case 40:
                                  case 41:
                                  case 42:
                                  case 43:
                                  case 44:
                                  case 45:
                                  case 46:
                                  case 47:
                                    /* background */
                                    term->curr_attr &= ~ATTR_BGMASK;
                                    term->curr_attr |=
                                        (term->esc_args[i] - 40)<<ATTR_BGSHIFT;
                                    break;
                                  case 49:      /* default-background */
                                    term->curr_attr &= ~ATTR_BGMASK;
                                    term->curr_attr |= ATTR_DEFBG;
                                    break;
                                }
                            }
                            if (term->use_bce)
                                term->erase_char = (' ' | ATTR_ASCII |
                                                    (term->curr_attr & 
                                                     (ATTR_FGMASK |
                                                      ATTR_BGMASK)));
                        }
                        break;
                      case 's':       /* save cursor */
                        save_cursor(term, TRUE);
                        break;
                      case 'u':       /* restore cursor */
                        save_cursor(term, FALSE);
                        term->seen_disp_event = TRUE;
                        break;
                      case 't':       /* set page size - ie window height */
                        /*
                         * VT340/VT420 sequence DECSLPP, DEC only allows values
                         *  24/25/36/48/72/144 other emulators (eg dtterm) use
                         * illegal values (eg first arg 1..9) for window changing 
                         * and reports.
                         */
                        if (term->esc_nargs <= 1
                            && (term->esc_args[0] < 1 ||
                                term->esc_args[0] >= 24)) {
                            compatibility(VT340TEXT);
                            if (!term->cfg->no_remote_resize)
                                request_resize(term->frontend, term->cols,
                                               def(term->esc_args[0], 24));
                            deselect(term);
                        } else if (term->esc_nargs >= 1 &&
                                   term->esc_args[0] >= 1 &&
                                   term->esc_args[0] < 24) {
                            compatibility(OTHER);

                            switch (term->esc_args[0]) {
                                int x, y, len;
                                char buf[80], *p;
                              case 1:
                                set_iconic(term->frontend, FALSE);
                                break;
                              case 2:
                                set_iconic(term->frontend, TRUE);
                                break;
                              case 3:
                                if (term->esc_nargs >= 3) {
                                    if (!term->cfg->no_remote_resize)
                                        move_window(term->frontend,
                                                    def(term->esc_args[1], 0),
                                                    def(term->esc_args[2], 0));
                                }
                                break;
                              case 4:
                                /* We should resize the window to a given
                                 * size in pixels here, but currently our
                                 * resizing code isn't healthy enough to
                                 * manage it. */
                                break;
                              case 5:
                                /* move to top */
                                set_zorder(term->frontend, TRUE);
                                break;
                              case 6:
                                /* move to bottom */
                                set_zorder(term->frontend, FALSE);
                                break;
                              case 7:
                                refresh_window(term->frontend);
                                break;
                              case 8:
                                if (term->esc_nargs >= 3) {
                                    if (!term->cfg->no_remote_resize)
                                        request_resize(term->frontend,
                                                       def(term->esc_args[2], term->cfg->width),
                                                       def(term->esc_args[1], term->cfg->height));
                                }
                                break;
                              case 9:
                                if (term->esc_nargs >= 2)
                                    set_zoomed(term->frontend,
                                               term->esc_args[1] ?
                                               TRUE : FALSE);
                                break;
                              case 11:
                                if (term->ldisc)
                                    ldisc_send(term->ldisc,
                                               is_iconic(term->frontend) ?
                                               "\033[1t" : "\033[2t", 4, 0);
                                break;
                              case 13:
                                if (term->ldisc) {
                                    get_window_pos(term->frontend, &x, &y);
                                    len = sprintf(buf, "\033[3;%d;%dt", x, y);
                                    ldisc_send(term->ldisc, buf, len, 0);
                                }
                                break;
                              case 14:
                                if (term->ldisc) {
                                    get_window_pixels(term->frontend, &x, &y);
                                    len = sprintf(buf, "\033[4;%d;%dt", x, y);
                                    ldisc_send(term->ldisc, buf, len, 0);
                                }
                                break;
                              case 18:
                                if (term->ldisc) {
                                    len = sprintf(buf, "\033[8;%d;%dt",
                                                  term->rows, term->cols);
                                    ldisc_send(term->ldisc, buf, len, 0);
                                }
                                break;
                              case 19:
                                /*
                                 * Hmmm. Strictly speaking we
                                 * should return `the size of the
                                 * screen in characters', but
                                 * that's not easy: (a) window
                                 * furniture being what it is it's
                                 * hard to compute, and (b) in
                                 * resize-font mode maximising the
                                 * window wouldn't change the
                                 * number of characters. *shrug*. I
                                 * think we'll ignore it for the
                                 * moment and see if anyone
                                 * complains, and then ask them
                                 * what they would like it to do.
                                 */
                                break;
                              case 20:
                                if (term->ldisc) {
                                    p = get_window_title(term->frontend, TRUE);
                                    len = strlen(p);
                                    ldisc_send(term->ldisc, "\033]L", 3, 0);
                                    ldisc_send(term->ldisc, p, len, 0);
                                    ldisc_send(term->ldisc, "\033\\", 2, 0);
                                }
                                break;
                              case 21:
                                if (term->ldisc) {
                                    p = get_window_title(term->frontend,FALSE);
                                    len = strlen(p);
                                    ldisc_send(term->ldisc, "\033]l", 3, 0);
                                    ldisc_send(term->ldisc, p, len, 0);
                                    ldisc_send(term->ldisc, "\033\\", 2, 0);
                                }
                                break;
                            }
                        }
                        break;
                      case 'S':
                        compatibility(SCOANSI);
                        scroll(term, term->marg_t, term->marg_b,
                               def(term->esc_args[0], 1), TRUE);
                        fix_cpos;
                        term->wrapnext = FALSE;
                        term->seen_disp_event = TRUE;
                        break;
                      case 'T':
                        compatibility(SCOANSI);
                        scroll(term, term->marg_t, term->marg_b,
                               -def(term->esc_args[0], 1), TRUE);
                        fix_cpos;
                        term->wrapnext = FALSE;
                        term->seen_disp_event = TRUE;
                        break;
                      case ANSI('|', '*'):
                        /* VT420 sequence DECSNLS
                         * Set number of lines on screen
                         * VT420 uses VGA like hardware and can support any size in
                         * reasonable range (24..49 AIUI) with no default specified.
                         */
                        compatibility(VT420);
                        if (term->esc_nargs == 1 && term->esc_args[0] > 0) {
                            if (!term->cfg->no_remote_resize)
                                request_resize(term->frontend, term->cols,
                                               def(term->esc_args[0],
                                                   term->cfg->height));
                            deselect(term);
                        }
                        break;
                      case ANSI('|', '$'):
                        /* VT340/VT420 sequence DECSCPP
                         * Set number of columns per page
                         * Docs imply range is only 80 or 132, but I'll allow any.
                         */
                        compatibility(VT340TEXT);
                        if (term->esc_nargs <= 1) {
                            if (!term->cfg->no_remote_resize)
                                request_resize(term->frontend,
                                               def(term->esc_args[0],
                                                   term->cfg->width), term->rows);
                            deselect(term);
                        }
                        break;
                      case 'X':       /* write N spaces w/o moving cursor */
                        /* XXX VTTEST says this is vt220, vt510 manual says vt100 */
                        compatibility(ANSIMIN);
                        {
                            int n = def(term->esc_args[0], 1);
                            pos cursplus;
                            unsigned long *p = term->cpos;
                            if (n > term->cols - term->curs.x)
                                n = term->cols - term->curs.x;
                            cursplus = term->curs;
                            cursplus.x += n;
                            check_boundary(term, term->curs.x, term->curs.y);
                            check_boundary(term, term->curs.x+n, term->curs.y);
                            check_selection(term, term->curs, cursplus);
                            while (n--)
                                *p++ = term->erase_char;
                            term->seen_disp_event = TRUE;
                        }
                        break;
                      case 'x':       /* report terminal characteristics */
                        compatibility(VT100);
                        if (term->ldisc) {
                            char buf[32];
                            int i = def(term->esc_args[0], 0);
                            if (i == 0 || i == 1) {
                                strcpy(buf, "\033[2;1;1;112;112;1;0x");
                                buf[2] += i;
                                ldisc_send(term->ldisc, buf, 20, 0);
                            }
                        }
                        break;
                      case 'Z':         /* BackTab for xterm */
                        compatibility(OTHER);
                        {
                            int i = def(term->esc_args[0], 1);
                            pos old_curs = term->curs;

                            for(;i>0 && term->curs.x>0; i--) {
                                do {
                                    term->curs.x--;
                                } while (term->curs.x >0 &&
                                         !term->tabs[term->curs.x]);
                            }
                            fix_cpos;
                            check_selection(term, old_curs, term->curs);
                        }
                        break;
                      case ANSI('L', '='):
                        compatibility(OTHER);
                        term->use_bce = (term->esc_args[0] <= 0);
                        term->erase_char = ERASE_CHAR;
                        if (term->use_bce)
                            term->erase_char = (' ' | ATTR_ASCII |
                                                (term->curr_attr & 
                                                 (ATTR_FGMASK | ATTR_BGMASK)));
                        break;
                      case ANSI('E', '='):
                        compatibility(OTHER);
                        term->blink_is_real = (term->esc_args[0] >= 1);
                        break;
                      case ANSI('p', '"'):
                        /*
                         * Allow the host to make this emulator a
                         * 'perfect' VT102. This first appeared in
                         * the VT220, but we do need to get back to
                         * PuTTY mode so I won't check it.
                         *
                         * The arg in 40..42,50 are a PuTTY extension.
                         * The 2nd arg, 8bit vs 7bit is not checked.
                         *
                         * Setting VT102 mode should also change
                         * the Fkeys to generate PF* codes as a
                         * real VT102 has no Fkeys. The VT220 does
                         * this, F11..F13 become ESC,BS,LF other
                         * Fkeys send nothing.
                         *
                         * Note ESC c will NOT change this!
                         */

                        switch (term->esc_args[0]) {
                          case 61:
                            term->compatibility_level &= ~TM_VTXXX;
                            term->compatibility_level |= TM_VT102;
                            break;
                          case 62:
                            term->compatibility_level &= ~TM_VTXXX;
                            term->compatibility_level |= TM_VT220;
                            break;

                          default:
                            if (term->esc_args[0] > 60 &&
                                term->esc_args[0] < 70)
                                term->compatibility_level |= TM_VTXXX;
                            break;

                          case 40:
                            term->compatibility_level &= TM_VTXXX;
                            break;
                          case 41:
                            term->compatibility_level = TM_PUTTY;
                            break;
                          case 42:
                            term->compatibility_level = TM_SCOANSI;
                            break;

                          case ARG_DEFAULT:
                            term->compatibility_level = TM_PUTTY;
                            break;
                          case 50:
                            break;
                        }

                        /* Change the response to CSI c */
                        if (term->esc_args[0] == 50) {
                            int i;
                            char lbuf[64];
                            strcpy(term->id_string, "\033[?");
                            for (i = 1; i < term->esc_nargs; i++) {
                                if (i != 1)
                                    strcat(term->id_string, ";");
                                sprintf(lbuf, "%d", term->esc_args[i]);
                                strcat(term->id_string, lbuf);
                            }
                            strcat(term->id_string, "c");
                        }
#if 0
                        /* Is this a good idea ? 
                         * Well we should do a soft reset at this point ...
                         */
                        if (!has_compat(VT420) && has_compat(VT100)) {
                            if (!term->cfg->no_remote_resize) {
                                if (term->reset_132)
                                    request_resize(132, 24);
                                else
                                    request_resize(80, 24);
                            }
                        }
#endif
                        break;
                    }
                break;
              case SEEN_OSC:
                term->osc_w = FALSE;
                switch (c) {
                  case 'P':            /* Linux palette sequence */
                    term->termstate = SEEN_OSC_P;
                    term->osc_strlen = 0;
                    break;
                  case 'R':            /* Linux palette reset */
                    palette_reset(term->frontend);
                    term_invalidate(term);
                    term->termstate = TOPLEVEL;
                    break;
                  case 'W':            /* word-set */
                    term->termstate = SEEN_OSC_W;
                    term->osc_w = TRUE;
                    break;
                  case '0':
                  case '1':
                  case '2':
                  case '3':
                  case '4':
                  case '5':
                  case '6':
                  case '7':
                  case '8':
                  case '9':
                    term->esc_args[0] = 10 * term->esc_args[0] + c - '0';
                    break;
                  case 'L':
                    /*
                     * Grotty hack to support xterm and DECterm title
                     * sequences concurrently.
                     */
                    if (term->esc_args[0] == 2) {
                        term->esc_args[0] = 1;
                        break;
                    }
                    /* else fall through */
                  default:
                    term->termstate = OSC_STRING;
                    term->osc_strlen = 0;
                }
                break;
              case OSC_STRING:
                /*
                 * This OSC stuff is EVIL. It takes just one character to get into
                 * sysline mode and it's not initially obvious how to get out.
                 * So I've added CR and LF as string aborts.
                 * This shouldn't effect compatibility as I believe embedded 
                 * control characters are supposed to be interpreted (maybe?) 
                 * and they don't display anything useful anyway.
                 *
                 * -- RDB
                 */
                if (c == '\012' || c == '\015') {
                    term->termstate = TOPLEVEL;
                } else if (c == 0234 || c == '\007') {
                    /*
                     * These characters terminate the string; ST and BEL
                     * terminate the sequence and trigger instant
                     * processing of it, whereas ESC goes back to SEEN_ESC
                     * mode unless it is followed by \, in which case it is
                     * synonymous with ST in the first place.
                     */
                    do_osc(term);
                    term->termstate = TOPLEVEL;
                } else if (c == '\033')
                    term->termstate = OSC_MAYBE_ST;
                else if (term->osc_strlen < OSC_STR_MAX)
                    term->osc_string[term->osc_strlen++] = c;
                break;
              case SEEN_OSC_P:
                {
                    int max = (term->osc_strlen == 0 ? 21 : 16);
                    int val;
                    if (c >= '0' && c <= '9')
                        val = c - '0';
                    else if (c >= 'A' && c <= 'A' + max - 10)
                        val = c - 'A' + 10;
                    else if (c >= 'a' && c <= 'a' + max - 10)
                        val = c - 'a' + 10;
                    else {
                        term->termstate = TOPLEVEL;
                        break;
                    }
                    term->osc_string[term->osc_strlen++] = val;
                    if (term->osc_strlen >= 7) {
                        palette_set(term->frontend, term->osc_string[0],
                                    term->osc_string[1] * 16 + term->osc_string[2],
                                    term->osc_string[3] * 16 + term->osc_string[4],
                                    term->osc_string[5] * 16 + term->osc_string[6]);
                        term_invalidate(term);
                        term->termstate = TOPLEVEL;
                    }
                }
                break;
              case SEEN_OSC_W:
                switch (c) {
                  case '0':
                  case '1':
                  case '2':
                  case '3':
                  case '4':
                  case '5':
                  case '6':
                  case '7':
                  case '8':
                  case '9':
                    term->esc_args[0] = 10 * term->esc_args[0] + c - '0';
                    break;
                  default:
                    term->termstate = OSC_STRING;
                    term->osc_strlen = 0;
                }
                break;
              case VT52_ESC:
                term->termstate = TOPLEVEL;
                term->seen_disp_event = TRUE;
                switch (c) {
                  case 'A':
                    move(term, term->curs.x, term->curs.y - 1, 1);
                    break;
                  case 'B':
                    move(term, term->curs.x, term->curs.y + 1, 1);
                    break;
                  case 'C':
                    move(term, term->curs.x + 1, term->curs.y, 1);
                    break;
                  case 'D':
                    move(term, term->curs.x - 1, term->curs.y, 1);
                    break;
                    /*
                     * From the VT100 Manual
                     * NOTE: The special graphics characters in the VT100
                     *       are different from those in the VT52
                     *
                     * From VT102 manual:
                     *       137 _  Blank             - Same
                     *       140 `  Reserved          - Humm.
                     *       141 a  Solid rectangle   - Similar
                     *       142 b  1/                - Top half of fraction for the
                     *       143 c  3/                - subscript numbers below.
                     *       144 d  5/
                     *       145 e  7/
                     *       146 f  Degrees           - Same
                     *       147 g  Plus or minus     - Same
                     *       150 h  Right arrow
                     *       151 i  Ellipsis (dots)
                     *       152 j  Divide by
                     *       153 k  Down arrow
                     *       154 l  Bar at scan 0
                     *       155 m  Bar at scan 1
                     *       156 n  Bar at scan 2
                     *       157 o  Bar at scan 3     - Similar
                     *       160 p  Bar at scan 4     - Similar
                     *       161 q  Bar at scan 5     - Similar
                     *       162 r  Bar at scan 6     - Same
                     *       163 s  Bar at scan 7     - Similar
                     *       164 t  Subscript 0
                     *       165 u  Subscript 1
                     *       166 v  Subscript 2
                     *       167 w  Subscript 3
                     *       170 x  Subscript 4
                     *       171 y  Subscript 5
                     *       172 z  Subscript 6
                     *       173 {  Subscript 7
                     *       174 |  Subscript 8
                     *       175 }  Subscript 9
                     *       176 ~  Paragraph
                     *
                     */
                  case 'F':
                    term->cset_attr[term->cset = 0] = ATTR_LINEDRW;
                    break;
                  case 'G':
                    term->cset_attr[term->cset = 0] = ATTR_ASCII;
                    break;
                  case 'H':
                    move(term, 0, 0, 0);
                    break;
                  case 'I':
                    if (term->curs.y == 0)
                        scroll(term, 0, term->rows - 1, -1, TRUE);
                    else if (term->curs.y > 0)
                        term->curs.y--;
                    fix_cpos;
                    term->wrapnext = FALSE;
                    break;
                  case 'J':
                    erase_lots(term, FALSE, FALSE, TRUE);
                    term->disptop = 0;
                    break;
                  case 'K':
                    erase_lots(term, TRUE, FALSE, TRUE);
                    break;
#if 0
                  case 'V':
                    /* XXX Print cursor line */
                    break;
                  case 'W':
                    /* XXX Start controller mode */
                    break;
                  case 'X':
                    /* XXX Stop controller mode */
                    break;
#endif
                  case 'Y':
                    term->termstate = VT52_Y1;
                    break;
                  case 'Z':
                    if (term->ldisc)
                        ldisc_send(term->ldisc, "\033/Z", 3, 0);
                    break;
                  case '=':
                    term->app_keypad_keys = TRUE;
                    break;
                  case '>':
                    term->app_keypad_keys = FALSE;
                    break;
                  case '<':
                    /* XXX This should switch to VT100 mode not current or default
                     *     VT mode. But this will only have effect in a VT220+
                     *     emulation.
                     */
                    term->vt52_mode = FALSE;
                    term->blink_is_real = term->cfg->blinktext;
                    break;
#if 0
                  case '^':
                    /* XXX Enter auto print mode */
                    break;
                  case '_':
                    /* XXX Exit auto print mode */
                    break;
                  case ']':
                    /* XXX Print screen */
                    break;
#endif

#ifdef VT52_PLUS
                  case 'E':
                    /* compatibility(ATARI) */
                    move(term, 0, 0, 0);
                    erase_lots(term, FALSE, FALSE, TRUE);
                    term->disptop = 0;
                    break;
                  case 'L':
                    /* compatibility(ATARI) */
                    if (term->curs.y <= term->marg_b)
                        scroll(term, term->curs.y, term->marg_b, -1, FALSE);
                    break;
                  case 'M':
                    /* compatibility(ATARI) */
                    if (term->curs.y <= term->marg_b)
                        scroll(term, term->curs.y, term->marg_b, 1, TRUE);
                    break;
                  case 'b':
                    /* compatibility(ATARI) */
                    term->termstate = VT52_FG;
                    break;
                  case 'c':
                    /* compatibility(ATARI) */
                    term->termstate = VT52_BG;
                    break;
                  case 'd':
                    /* compatibility(ATARI) */
                    erase_lots(term, FALSE, TRUE, FALSE);
                    term->disptop = 0;
                    break;
                  case 'e':
                    /* compatibility(ATARI) */
                    term->cursor_on = TRUE;
                    break;
                  case 'f':
                    /* compatibility(ATARI) */
                    term->cursor_on = FALSE;
                    break;
                    /* case 'j': Save cursor position - broken on ST */
                    /* case 'k': Restore cursor position */
                  case 'l':
                    /* compatibility(ATARI) */
                    erase_lots(term, TRUE, TRUE, TRUE);
                    term->curs.x = 0;
                    term->wrapnext = FALSE;
                    fix_cpos;
                    break;
                  case 'o':
                    /* compatibility(ATARI) */
                    erase_lots(term, TRUE, TRUE, FALSE);
                    break;
                  case 'p':
                    /* compatibility(ATARI) */
                    term->curr_attr |= ATTR_REVERSE;
                    break;
                  case 'q':
                    /* compatibility(ATARI) */
                    term->curr_attr &= ~ATTR_REVERSE;
                    break;
                  case 'v':            /* wrap Autowrap on - Wyse style */
                    /* compatibility(ATARI) */
                    term->wrap = 1;
                    break;
                  case 'w':            /* Autowrap off */
                    /* compatibility(ATARI) */
                    term->wrap = 0;
                    break;

                  case 'R':
                    /* compatibility(OTHER) */
                    term->vt52_bold = FALSE;
                    term->curr_attr = ATTR_DEFAULT;
                    if (term->use_bce)
                        term->erase_char = (' ' | ATTR_ASCII |
                                            (term->curr_attr & 
                                             (ATTR_FGMASK | ATTR_BGMASK)));
                    break;
                  case 'S':
                    /* compatibility(VI50) */
                    term->curr_attr |= ATTR_UNDER;
                    break;
                  case 'W':
                    /* compatibility(VI50) */
                    term->curr_attr &= ~ATTR_UNDER;
                    break;
                  case 'U':
                    /* compatibility(VI50) */
                    term->vt52_bold = TRUE;
                    term->curr_attr |= ATTR_BOLD;
                    break;
                  case 'T':
                    /* compatibility(VI50) */
                    term->vt52_bold = FALSE;
                    term->curr_attr &= ~ATTR_BOLD;
                    break;
#endif
                }
                break;
              case VT52_Y1:
                term->termstate = VT52_Y2;
                move(term, term->curs.x, c - ' ', 0);
                break;
              case VT52_Y2:
                term->termstate = TOPLEVEL;
                move(term, c - ' ', term->curs.y, 0);
                break;

#ifdef VT52_PLUS
              case VT52_FG:
                term->termstate = TOPLEVEL;
                term->curr_attr &= ~ATTR_FGMASK;
                term->curr_attr &= ~ATTR_BOLD;
                term->curr_attr |= (c & 0x7) << ATTR_FGSHIFT;
                if ((c & 0x8) || term->vt52_bold)
                    term->curr_attr |= ATTR_BOLD;

                if (term->use_bce)
                    term->erase_char = (' ' | ATTR_ASCII |
                                        (term->curr_attr &
                                         (ATTR_FGMASK | ATTR_BGMASK)));
                break;
              case VT52_BG:
                term->termstate = TOPLEVEL;
                term->curr_attr &= ~ATTR_BGMASK;
                term->curr_attr &= ~ATTR_BLINK;
                term->curr_attr |= (c & 0x7) << ATTR_BGSHIFT;

                /* Note: bold background */
                if (c & 0x8)
                    term->curr_attr |= ATTR_BLINK;

                if (term->use_bce)
                    term->erase_char = (' ' | ATTR_ASCII |
                                        (term->curr_attr &
                                         (ATTR_FGMASK | ATTR_BGMASK)));
                break;
#endif
              default: break;          /* placate gcc warning about enum use */
            }
        if (term->selstate != NO_SELECTION) {
            pos cursplus = term->curs;
            incpos(cursplus);
            check_selection(term, term->curs, cursplus);
        }
    }

    term_print_flush(term);
}

#if 0
/*
 * Compare two lines to determine whether they are sufficiently
 * alike to scroll-optimise one to the other. Return the degree of
 * similarity.
 */
static int linecmp(Terminal *term, unsigned long *a, unsigned long *b)
{
    int i, n;

    for (i = n = 0; i < term->cols; i++)
        n += (*a++ == *b++);
    return n;
}
#endif

/*
 * Given a context, update the window. Out of paranoia, we don't
 * allow WM_PAINT responses to do scrolling optimisations.
 */
static void do_paint(Terminal *term, Context ctx, int may_optimise)
{
    int i, j, our_curs_y, our_curs_x;
    unsigned long rv, cursor;
    pos scrpos;
    char ch[1024];
    long cursor_background = ERASE_CHAR;
    unsigned long ticks;

    /*
     * Check the visual bell state.
     */
    if (term->in_vbell) {
        ticks = GETTICKCOUNT();
        if (ticks - term->vbell_startpoint >= VBELL_TIMEOUT)
            term->in_vbell = FALSE; 
   }

    rv = (!term->rvideo ^ !term->in_vbell ? ATTR_REVERSE : 0);

    /* Depends on:
     * screen array, disptop, scrtop,
     * selection, rv, 
     * cfg.blinkpc, blink_is_real, tblinker, 
     * curs.y, curs.x, blinker, cfg.blink_cur, cursor_on, has_focus, wrapnext
     */

    /* Has the cursor position or type changed ? */
    if (term->cursor_on) {
        if (term->has_focus) {
            if (term->blinker || !term->cfg->blink_cur)
                cursor = TATTR_ACTCURS;
            else
                cursor = 0;
        } else
            cursor = TATTR_PASCURS;
        if (term->wrapnext)
            cursor |= TATTR_RIGHTCURS;
    } else
        cursor = 0;
    our_curs_y = term->curs.y - term->disptop;
    {
        /*
         * Adjust the cursor position in the case where it's
         * resting on the right-hand half of a CJK wide character.
         * xterm's behaviour here, which seems adequate to me, is
         * to display the cursor covering the _whole_ character,
         * exactly as if it were one space to the left.
         */
        unsigned long *ldata = lineptr(term->curs.y);
        our_curs_x = term->curs.x;
        if (our_curs_x > 0 &&
            (ldata[our_curs_x] & (CHAR_MASK | CSET_MASK)) == UCSWIDE)
            our_curs_x--;
    }

    if (term->dispcurs && (term->curstype != cursor ||
                           term->dispcurs !=
                           term->disptext + our_curs_y * (term->cols + 1) +
                           our_curs_x)) {
        if (term->dispcurs > term->disptext && 
            (*term->dispcurs & (CHAR_MASK | CSET_MASK)) == UCSWIDE)
            term->dispcurs[-1] |= ATTR_INVALID;
        if ( (term->dispcurs[1] & (CHAR_MASK | CSET_MASK)) == UCSWIDE)
            term->dispcurs[1] |= ATTR_INVALID;
        *term->dispcurs |= ATTR_INVALID;
        term->curstype = 0;
    }
    term->dispcurs = NULL;

    /* The normal screen data */
    for (i = 0; i < term->rows; i++) {
        unsigned long *ldata;
        int lattr;
        int idx, dirty_line, dirty_run, selected;
        unsigned long attr = 0;
        int updated_line = 0;
        int start = 0;
        int ccount = 0;
        int last_run_dirty = 0;

        scrpos.y = i + term->disptop;
        ldata = lineptr(scrpos.y);
        lattr = (ldata[term->cols] & LATTR_MODE);

        idx = i * (term->cols + 1);
        dirty_run = dirty_line = (ldata[term->cols] !=
                                  term->disptext[idx + term->cols]);
        term->disptext[idx + term->cols] = ldata[term->cols];

        for (j = 0; j < term->cols; j++, idx++) {
            unsigned long tattr, tchar;
            unsigned long *d = ldata + j;
            int break_run;
            scrpos.x = j;

            tchar = (*d & (CHAR_MASK | CSET_MASK));
            tattr = (*d & (ATTR_MASK ^ CSET_MASK));
            switch (tchar & CSET_MASK) {
              case ATTR_ASCII:
                tchar = unitab_line[tchar & 0xFF];
                break;
              case ATTR_LINEDRW:
                tchar = unitab_xterm[tchar & 0xFF];
                break;
              case ATTR_SCOACS:  
                tchar = unitab_scoacs[tchar&0xFF]; 
                break;
            }
            tattr |= (tchar & CSET_MASK);
            tchar &= CHAR_MASK;
            if ((d[1] & (CHAR_MASK | CSET_MASK)) == UCSWIDE)
                    tattr |= ATTR_WIDE;

            /* Video reversing things */
            if (term->selstate == DRAGGING || term->selstate == SELECTED) {
                if (term->seltype == LEXICOGRAPHIC)
                    selected = (posle(term->selstart, scrpos) &&
                                poslt(scrpos, term->selend));
                else
                    selected = (posPle(term->selstart, scrpos) &&
                                posPlt(scrpos, term->selend));
            } else
                selected = FALSE;
            tattr = (tattr ^ rv
                     ^ (selected ? ATTR_REVERSE : 0));

            /* 'Real' blinking ? */
            if (term->blink_is_real && (tattr & ATTR_BLINK)) {
                if (term->has_focus && term->tblinker) {
                    tchar = ' ';
                    tattr &= ~CSET_MASK;
                    tattr |= ATTR_ACP;
                }
                tattr &= ~ATTR_BLINK;
            }

            /*
             * Check the font we'll _probably_ be using to see if 
             * the character is wide when we don't want it to be.
             */
            if ((tchar | tattr) != (term->disptext[idx]& ~ATTR_NARROW)) {
                if ((tattr & ATTR_WIDE) == 0 && 
                    char_width(ctx, (tchar | tattr) & 0xFFFF) == 2)
                    tattr |= ATTR_NARROW;
            } else if (term->disptext[idx]&ATTR_NARROW)
                tattr |= ATTR_NARROW;

            /* Cursor here ? Save the 'background' */
            if (i == our_curs_y && j == our_curs_x) {
                cursor_background = tattr | tchar;
                term->dispcurs = term->disptext + idx;
            }

            if ((term->disptext[idx] ^ tattr) & ATTR_WIDE)
                dirty_line = TRUE;

            break_run = (((tattr ^ attr) & term->attr_mask) ||
                j - start >= sizeof(ch));

            /* Special hack for VT100 Linedraw glyphs */
            if ((attr & CSET_MASK) == 0x2300 && tchar >= 0xBA
                && tchar <= 0xBD) break_run = TRUE;

            if (!dbcs_screenfont && !dirty_line) {
                if ((tchar | tattr) == term->disptext[idx])
                    break_run = TRUE;
                else if (!dirty_run && ccount == 1)
                    break_run = TRUE;
            }

            if (break_run) {
                if ((dirty_run || last_run_dirty) && ccount > 0) {
                    do_text(ctx, start, i, ch, ccount, attr, lattr);
                    updated_line = 1;
                }
                start = j;
                ccount = 0;
                attr = tattr;
                if (dbcs_screenfont)
                    last_run_dirty = dirty_run;
                dirty_run = dirty_line;
            }

            if ((tchar | tattr) != term->disptext[idx])
                dirty_run = TRUE;
            ch[ccount++] = (char) tchar;
            term->disptext[idx] = tchar | tattr;

            /* If it's a wide char step along to the next one. */
            if (tattr & ATTR_WIDE) {
                if (++j < term->cols) {
                    idx++;
                    d++;
                    /*
                     * By construction above, the cursor should not
                     * be on the right-hand half of this character.
                     * Ever.
                     */
                    assert(!(i == our_curs_y && j == our_curs_x));
                    if (term->disptext[idx] != *d)
                        dirty_run = TRUE;
                    term->disptext[idx] = *d;
                }
            }
        }
        if (dirty_run && ccount > 0) {
            do_text(ctx, start, i, ch, ccount, attr, lattr);
            updated_line = 1;
        }

        /* Cursor on this line ? (and changed) */
        if (i == our_curs_y && (term->curstype != cursor || updated_line)) {
            ch[0] = (char) (cursor_background & CHAR_MASK);
            attr = (cursor_background & ATTR_MASK) | cursor;
            do_cursor(ctx, our_curs_x, i, ch, 1, attr, lattr);
            term->curstype = cursor;
        }
    }
}

/*
 * Flick the switch that says if blinking things should be shown or hidden.
 */

void term_blink(Terminal *term, int flg)
{
    long now, blink_diff;

    now = GETTICKCOUNT();
    blink_diff = now - term->last_tblink;

    /* Make sure the text blinks no more than 2Hz; we'll use 0.45 s period. */
    if (blink_diff < 0 || blink_diff > (TICKSPERSEC * 9 / 20)) {
        term->last_tblink = now;
        term->tblinker = !term->tblinker;
    }

    if (flg) {
        term->blinker = 1;
        term->last_blink = now;
        return;
    }

    blink_diff = now - term->last_blink;

    /* Make sure the cursor blinks no faster than system blink rate */
    if (blink_diff >= 0 && blink_diff < (long) CURSORBLINK)
        return;

    term->last_blink = now;
    term->blinker = !term->blinker;
}

/*
 * Invalidate the whole screen so it will be repainted in full.
 */
void term_invalidate(Terminal *term)
{
    int i;

    for (i = 0; i < term->rows * (term->cols + 1); i++)
        term->disptext[i] = ATTR_INVALID;
}

/*
 * Paint the window in response to a WM_PAINT message.
 */
void term_paint(Terminal *term, Context ctx,
                int left, int top, int right, int bottom, int immediately)
{
    int i, j;
    if (left < 0) left = 0;
    if (top < 0) top = 0;
    if (right >= term->cols) right = term->cols-1;
    if (bottom >= term->rows) bottom = term->rows-1;

    for (i = top; i <= bottom && i < term->rows; i++) {
        if ((term->disptext[i * (term->cols + 1) + term->cols] &
             LATTR_MODE) == LATTR_NORM)
            for (j = left; j <= right && j < term->cols; j++)
                term->disptext[i * (term->cols + 1) + j] = ATTR_INVALID;
        else
            for (j = left / 2; j <= right / 2 + 1 && j < term->cols; j++)
                term->disptext[i * (term->cols + 1) + j] = ATTR_INVALID;
    }

    /* This should happen soon enough, also for some reason it sometimes 
     * fails to actually do anything when re-sizing ... painting the wrong
     * window perhaps ?
     */
    if (immediately)
        do_paint (term, ctx, FALSE);
}

/*
 * Attempt to scroll the scrollback. The second parameter gives the
 * position we want to scroll to; the first is +1 to denote that
 * this position is relative to the beginning of the scrollback, -1
 * to denote it is relative to the end, and 0 to denote that it is
 * relative to the current position.
 */
void term_scroll(Terminal *term, int rel, int where)
{
    int sbtop = -count234(term->scrollback);
#ifdef OPTIMISE_SCROLL
    int olddisptop = term->disptop;
    int shift;
#endif /* OPTIMISE_SCROLL */

    term->disptop = (rel < 0 ? 0 : rel > 0 ? sbtop : term->disptop) + where;
    if (term->disptop < sbtop)
        term->disptop = sbtop;
    if (term->disptop > 0)
        term->disptop = 0;
    update_sbar(term);
#ifdef OPTIMISE_SCROLL
    shift = (term->disptop - olddisptop);
    if (shift < term->rows && shift > -term->rows)
        scroll_display(term, 0, term->rows - 1, shift);
#endif /* OPTIMISE_SCROLL */
    term_update(term);
}

static void clipme(Terminal *term, pos top, pos bottom, int rect)
{
    wchar_t *workbuf;
    wchar_t *wbptr;                    /* where next char goes within workbuf */
    int old_top_x;
    int wblen = 0;                     /* workbuf len */
    int buflen;                        /* amount of memory allocated to workbuf */

    buflen = 5120;                     /* Default size */
    workbuf = smalloc(buflen * sizeof(wchar_t));
    wbptr = workbuf;                   /* start filling here */
    old_top_x = top.x;                 /* needed for rect==1 */

    while (poslt(top, bottom)) {
        int nl = FALSE;
        unsigned long *ldata = lineptr(top.y);
        pos nlpos;

        /*
         * nlpos will point at the maximum position on this line we
         * should copy up to. So we start it at the end of the
         * line...
         */
        nlpos.y = top.y;
        nlpos.x = term->cols;

        /*
         * ... move it backwards if there's unused space at the end
         * of the line (and also set `nl' if this is the case,
         * because in normal selection mode this means we need a
         * newline at the end)...
         */
        if (!(ldata[term->cols] & LATTR_WRAPPED)) {
            while (((ldata[nlpos.x - 1] & 0xFF) == 0x20 ||
                    (DIRECT_CHAR(ldata[nlpos.x - 1]) &&
                     (ldata[nlpos.x - 1] & CHAR_MASK) == 0x20))
                   && poslt(top, nlpos))
                decpos(nlpos);
            if (poslt(nlpos, bottom))
                nl = TRUE;
        } else if (ldata[term->cols] & LATTR_WRAPPED2) {
            /* Ignore the last char on the line in a WRAPPED2 line. */
            decpos(nlpos);
        }

        /*
         * ... and then clip it to the terminal x coordinate if
         * we're doing rectangular selection. (In this case we
         * still did the above, so that copying e.g. the right-hand
         * column from a table doesn't fill with spaces on the
         * right.)
         */
        if (rect) {
            if (nlpos.x > bottom.x)
                nlpos.x = bottom.x;
            nl = (top.y < bottom.y);
        }

        while (poslt(top, bottom) && poslt(top, nlpos)) {
#if 0
            char cbuf[16], *p;
            sprintf(cbuf, "<U+%04x>", (ldata[top.x] & 0xFFFF));
#else
            wchar_t cbuf[16], *p;
            int uc = (ldata[top.x] & 0xFFFF);
            int set, c;

            if (uc == UCSWIDE) {
                top.x++;
                continue;
            }

            switch (uc & CSET_MASK) {
              case ATTR_LINEDRW:
                if (!term->cfg->rawcnp) {
                    uc = unitab_xterm[uc & 0xFF];
                    break;
                }
              case ATTR_ASCII:
                uc = unitab_line[uc & 0xFF];
                break;
              case ATTR_SCOACS:  
                uc = unitab_scoacs[uc&0xFF]; 
                break;
            }
            switch (uc & CSET_MASK) {
              case ATTR_ACP:
                uc = unitab_font[uc & 0xFF];
                break;
              case ATTR_OEMCP:
                uc = unitab_oemcp[uc & 0xFF];
                break;
            }

            set = (uc & CSET_MASK);
            c = (uc & CHAR_MASK);
            cbuf[0] = uc;
            cbuf[1] = 0;

            if (DIRECT_FONT(uc)) {
                if (c >= ' ' && c != 0x7F) {
                    char buf[4];
                    WCHAR wbuf[4];
                    int rv;
                    if (is_dbcs_leadbyte(font_codepage, (BYTE) c)) {
                        buf[0] = c;
                        buf[1] = (char) (0xFF & ldata[top.x + 1]);
                        rv = mb_to_wc(font_codepage, 0, buf, 2, wbuf, 4);
                        top.x++;
                    } else {
                        buf[0] = c;
                        rv = mb_to_wc(font_codepage, 0, buf, 1, wbuf, 4);
                    }

                    if (rv > 0) {
                        memcpy(cbuf, wbuf, rv * sizeof(wchar_t));
                        cbuf[rv] = 0;
                    }
                }
            }
#endif

            for (p = cbuf; *p; p++) {
                /* Enough overhead for trailing NL and nul */
                if (wblen >= buflen - 16) {
                    workbuf =
                        srealloc(workbuf,
                                 sizeof(wchar_t) * (buflen += 100));
                    wbptr = workbuf + wblen;
                }
                wblen++;
                *wbptr++ = *p;
            }
            top.x++;
        }
        if (nl) {
            int i;
            for (i = 0; i < sel_nl_sz; i++) {
                wblen++;
                *wbptr++ = sel_nl[i];
            }
        }
        top.y++;
        top.x = rect ? old_top_x : 0;
    }
#if SELECTION_NUL_TERMINATED
    wblen++;
    *wbptr++ = 0;
#endif
    write_clip(term->frontend, workbuf, wblen, FALSE); /* transfer to clipbd */
    if (buflen > 0)                    /* indicates we allocated this buffer */
        sfree(workbuf);
}

void term_copyall(Terminal *term)
{
    pos top;
    top.y = -count234(term->scrollback);
    top.x = 0;
    clipme(term, top, term->curs, 0);
}

/*
 * The wordness array is mainly for deciding the disposition of the
 * US-ASCII characters.
 */
static int wordtype(Terminal *term, int uc)
{
    struct ucsword {
        int start, end, ctype;
    };
    static const struct ucsword ucs_words[] = {
        {
        128, 160, 0}, {
        161, 191, 1}, {
        215, 215, 1}, {
        247, 247, 1}, {
        0x037e, 0x037e, 1},            /* Greek question mark */
        {
        0x0387, 0x0387, 1},            /* Greek ano teleia */
        {
        0x055a, 0x055f, 1},            /* Armenian punctuation */
        {
        0x0589, 0x0589, 1},            /* Armenian full stop */
        {
        0x0700, 0x070d, 1},            /* Syriac punctuation */
        {
        0x104a, 0x104f, 1},            /* Myanmar punctuation */
        {
        0x10fb, 0x10fb, 1},            /* Georgian punctuation */
        {
        0x1361, 0x1368, 1},            /* Ethiopic punctuation */
        {
        0x166d, 0x166e, 1},            /* Canadian Syl. punctuation */
        {
        0x17d4, 0x17dc, 1},            /* Khmer punctuation */
        {
        0x1800, 0x180a, 1},            /* Mongolian punctuation */
        {
        0x2000, 0x200a, 0},            /* Various spaces */
        {
        0x2070, 0x207f, 2},            /* superscript */
        {
        0x2080, 0x208f, 2},            /* subscript */
        {
        0x200b, 0x27ff, 1},            /* punctuation and symbols */
        {
        0x3000, 0x3000, 0},            /* ideographic space */
        {
        0x3001, 0x3020, 1},            /* ideographic punctuation */
        {
        0x303f, 0x309f, 3},            /* Hiragana */
        {
        0x30a0, 0x30ff, 3},            /* Katakana */
        {
        0x3300, 0x9fff, 3},            /* CJK Ideographs */
        {
        0xac00, 0xd7a3, 3},            /* Hangul Syllables */
        {
        0xf900, 0xfaff, 3},            /* CJK Ideographs */
        {
        0xfe30, 0xfe6b, 1},            /* punctuation forms */
        {
        0xff00, 0xff0f, 1},            /* half/fullwidth ASCII */
        {
        0xff1a, 0xff20, 1},            /* half/fullwidth ASCII */
        {
        0xff3b, 0xff40, 1},            /* half/fullwidth ASCII */
        {
        0xff5b, 0xff64, 1},            /* half/fullwidth ASCII */
        {
        0xfff0, 0xffff, 0},            /* half/fullwidth ASCII */
        {
        0, 0, 0}
    };
    const struct ucsword *wptr;

    uc &= (CSET_MASK | CHAR_MASK);

    switch (uc & CSET_MASK) {
      case ATTR_LINEDRW:
        uc = unitab_xterm[uc & 0xFF];
        break;
      case ATTR_ASCII:
        uc = unitab_line[uc & 0xFF];
        break;
      case ATTR_SCOACS:  
        uc = unitab_scoacs[uc&0xFF]; 
        break;
    }
    switch (uc & CSET_MASK) {
      case ATTR_ACP:
        uc = unitab_font[uc & 0xFF];
        break;
      case ATTR_OEMCP:
        uc = unitab_oemcp[uc & 0xFF];
        break;
    }

    /* For DBCS font's I can't do anything usefull. Even this will sometimes
     * fail as there's such a thing as a double width space. :-(
     */
    if (dbcs_screenfont && font_codepage == line_codepage)
        return (uc != ' ');

    if (uc < 0x80)
        return term->wordness[uc];

    for (wptr = ucs_words; wptr->start; wptr++) {
        if (uc >= wptr->start && uc <= wptr->end)
            return wptr->ctype;
    }

    return 2;
}

/*
 * Spread the selection outwards according to the selection mode.
 */
static pos sel_spread_half(Terminal *term, pos p, int dir)
{
    unsigned long *ldata;
    short wvalue;
    int topy = -count234(term->scrollback);

    ldata = lineptr(p.y);

    switch (term->selmode) {
      case SM_CHAR:
        /*
         * In this mode, every character is a separate unit, except
         * for runs of spaces at the end of a non-wrapping line.
         */
        if (!(ldata[term->cols] & LATTR_WRAPPED)) {
            unsigned long *q = ldata + term->cols;
            while (q > ldata && (q[-1] & CHAR_MASK) == 0x20)
                q--;
            if (q == ldata + term->cols)
                q--;
            if (p.x >= q - ldata)
                p.x = (dir == -1 ? q - ldata : term->cols - 1);
        }
        break;
      case SM_WORD:
        /*
         * In this mode, the units are maximal runs of characters
         * whose `wordness' has the same value.
         */
        wvalue = wordtype(term, UCSGET(ldata, p.x));
        if (dir == +1) {
            while (1) {
                int maxcols = (ldata[term->cols] & LATTR_WRAPPED2 ?
                               term->cols-1 : term->cols);
                if (p.x < maxcols-1) {
                    if (wordtype(term, UCSGET(ldata, p.x + 1)) == wvalue)
                        p.x++;
                    else
                        break;
                } else {
                    if (ldata[term->cols] & LATTR_WRAPPED) {
                        unsigned long *ldata2;
                        ldata2 = lineptr(p.y+1);
                        if (wordtype(term, UCSGET(ldata2, 0)) == wvalue) {
                            p.x = 0;
                            p.y++;
                            ldata = ldata2;
                        } else
                            break;
                    } else
                        break;
                }
            }
        } else {
            while (1) {
                if (p.x > 0) {
                    if (wordtype(term, UCSGET(ldata, p.x - 1)) == wvalue)
                        p.x--;
                    else
                        break;
                } else {
                    unsigned long *ldata2;
                    int maxcols;
                    if (p.y <= topy)
                        break;
                    ldata2 = lineptr(p.y-1);
                    maxcols = (ldata2[term->cols] & LATTR_WRAPPED2 ?
                              term->cols-1 : term->cols);
                    if (ldata2[term->cols] & LATTR_WRAPPED) {
                        if (wordtype(term, UCSGET(ldata2, maxcols-1))
                            == wvalue) {
                            p.x = maxcols-1;
                            p.y--;
                            ldata = ldata2;
                        } else
                            break;
                    } else
                        break;
                }
            }
        }
        break;
      case SM_LINE:
        /*
         * In this mode, every line is a unit.
         */
        p.x = (dir == -1 ? 0 : term->cols - 1);
        break;
    }
    return p;
}

static void sel_spread(Terminal *term)
{
    if (term->seltype == LEXICOGRAPHIC) {
        term->selstart = sel_spread_half(term, term->selstart, -1);
        decpos(term->selend);
        term->selend = sel_spread_half(term, term->selend, +1);
        incpos(term->selend);
    }
}

void term_do_paste(Terminal *term)
{
    wchar_t *data;
    int len;

    get_clip(term->frontend, &data, &len);
    if (data && len > 0) {
        wchar_t *p, *q;

        term_seen_key_event(term);     /* pasted data counts */

        if (term->paste_buffer)
            sfree(term->paste_buffer);
        term->paste_pos = term->paste_hold = term->paste_len = 0;
        term->paste_buffer = smalloc(len * sizeof(wchar_t));

        p = q = data;
        while (p < data + len) {
            while (p < data + len &&
                   !(p <= data + len - sel_nl_sz &&
                     !memcmp(p, sel_nl, sizeof(sel_nl))))
                p++;

            {
                int i;
                for (i = 0; i < p - q; i++) {
                    term->paste_buffer[term->paste_len++] = q[i];
                }
            }

            if (p <= data + len - sel_nl_sz &&
                !memcmp(p, sel_nl, sizeof(sel_nl))) {
                term->paste_buffer[term->paste_len++] = '\015';
                p += sel_nl_sz;
            }
            q = p;
        }

        /* Assume a small paste will be OK in one go. */
        if (term->paste_len < 256) {
            if (term->ldisc)
                luni_send(term->ldisc, term->paste_buffer, term->paste_len, 0);
            if (term->paste_buffer)
                sfree(term->paste_buffer);
            term->paste_buffer = 0;
            term->paste_pos = term->paste_hold = term->paste_len = 0;
        }
    }
    get_clip(term->frontend, NULL, NULL);
}

void term_mouse(Terminal *term, Mouse_Button b, Mouse_Action a, int x, int y,
                int shift, int ctrl, int alt)
{
    pos selpoint;
    unsigned long *ldata;
    int raw_mouse = (term->xterm_mouse &&
                     !term->cfg->no_mouse_rep &&
                     !(term->cfg->mouse_override && shift));
    int default_seltype;

    if (y < 0) {
        y = 0;
        if (a == MA_DRAG && !raw_mouse)
            term_scroll(term, 0, -1);
    }
    if (y >= term->rows) {
        y = term->rows - 1;
        if (a == MA_DRAG && !raw_mouse)
            term_scroll(term, 0, +1);
    }
    if (x < 0) {
        if (y > 0) {
            x = term->cols - 1;
            y--;
        } else
            x = 0;
    }
    if (x >= term->cols)
        x = term->cols - 1;

    selpoint.y = y + term->disptop;
    selpoint.x = x;
    ldata = lineptr(selpoint.y);
    if ((ldata[term->cols] & LATTR_MODE) != LATTR_NORM)
        selpoint.x /= 2;

    if (raw_mouse) {
        int encstate = 0, r, c;
        char abuf[16];

        if (term->ldisc) {

            switch (b) {
              case MBT_LEFT:
                encstate = 0x20;               /* left button down */
                break;
              case MBT_MIDDLE:
                encstate = 0x21;
                break;
              case MBT_RIGHT:
                encstate = 0x22;
                break;
              case MBT_WHEEL_UP:
                encstate = 0x60;
                break;
              case MBT_WHEEL_DOWN:
                encstate = 0x61;
                break;
              default: break;          /* placate gcc warning about enum use */
            }
            switch (a) {
              case MA_DRAG:
                if (term->xterm_mouse == 1)
                    return;
                encstate += 0x20;
                break;
              case MA_RELEASE:
                encstate = 0x23;
                term->mouse_is_down = 0;
                break;
              case MA_CLICK:
                if (term->mouse_is_down == b)
                    return;
                term->mouse_is_down = b;
                break;
              default: break;          /* placate gcc warning about enum use */
            }
            if (shift)
                encstate += 0x04;
            if (ctrl)
                encstate += 0x10;
            r = y + 33;
            c = x + 33;

            sprintf(abuf, "\033[M%c%c%c", encstate, c, r);
            ldisc_send(term->ldisc, abuf, 6, 0);
        }
        return;
    }

    b = translate_button(term->frontend, b);

    /*
     * Set the selection type (rectangular or normal) at the start
     * of a selection attempt, from the state of Alt.
     */
    if (!alt ^ !term->cfg->rect_select)
        default_seltype = RECTANGULAR;
    else
        default_seltype = LEXICOGRAPHIC;
        
    if (term->selstate == NO_SELECTION) {
        term->seltype = default_seltype;
    }

    if (b == MBT_SELECT && a == MA_CLICK) {
        deselect(term);
        term->selstate = ABOUT_TO;
        term->seltype = default_seltype;
        term->selanchor = selpoint;
        term->selmode = SM_CHAR;
    } else if (b == MBT_SELECT && (a == MA_2CLK || a == MA_3CLK)) {
        deselect(term);
        term->selmode = (a == MA_2CLK ? SM_WORD : SM_LINE);
        term->selstate = DRAGGING;
        term->selstart = term->selanchor = selpoint;
        term->selend = term->selstart;
        incpos(term->selend);
        sel_spread(term);
    } else if ((b == MBT_SELECT && a == MA_DRAG) ||
               (b == MBT_EXTEND && a != MA_RELEASE)) {
        if (term->selstate == ABOUT_TO && poseq(term->selanchor, selpoint))
            return;
        if (b == MBT_EXTEND && a != MA_DRAG && term->selstate == SELECTED) {
            if (term->seltype == LEXICOGRAPHIC) {
                /*
                 * For normal selection, we extend by moving
                 * whichever end of the current selection is closer
                 * to the mouse.
                 */
                if (posdiff(selpoint, term->selstart) <
                    posdiff(term->selend, term->selstart) / 2) {
                    term->selanchor = term->selend;
                    decpos(term->selanchor);
                } else {
                    term->selanchor = term->selstart;
                }
            } else {
                /*
                 * For rectangular selection, we have a choice of
                 * _four_ places to put selanchor and selpoint: the
                 * four corners of the selection.
                 */
                if (2*selpoint.x < term->selstart.x + term->selend.x)
                    term->selanchor.x = term->selend.x-1;
                else
                    term->selanchor.x = term->selstart.x;

                if (2*selpoint.y < term->selstart.y + term->selend.y)
                    term->selanchor.y = term->selend.y;
                else
                    term->selanchor.y = term->selstart.y;
            }
            term->selstate = DRAGGING;
        }
        if (term->selstate != ABOUT_TO && term->selstate != DRAGGING)
            term->selanchor = selpoint;
        term->selstate = DRAGGING;
        if (term->seltype == LEXICOGRAPHIC) {
            /*
             * For normal selection, we set (selstart,selend) to
             * (selpoint,selanchor) in some order.
             */
            if (poslt(selpoint, term->selanchor)) {
                term->selstart = selpoint;
                term->selend = term->selanchor;
                incpos(term->selend);
            } else {
                term->selstart = term->selanchor;
                term->selend = selpoint;
                incpos(term->selend);
            }
        } else {
            /*
             * For rectangular selection, we may need to
             * interchange x and y coordinates (if the user has
             * dragged in the -x and +y directions, or vice versa).
             */
            term->selstart.x = min(term->selanchor.x, selpoint.x);
            term->selend.x = 1+max(term->selanchor.x, selpoint.x);
            term->selstart.y = min(term->selanchor.y, selpoint.y);
            term->selend.y =   max(term->selanchor.y, selpoint.y);
        }
        sel_spread(term);
    } else if ((b == MBT_SELECT || b == MBT_EXTEND) && a == MA_RELEASE) {
        if (term->selstate == DRAGGING) {
            /*
             * We've completed a selection. We now transfer the
             * data to the clipboard.
             */
            clipme(term, term->selstart, term->selend,
                   (term->seltype == RECTANGULAR));
            term->selstate = SELECTED;
        } else
            term->selstate = NO_SELECTION;
    } else if (b == MBT_PASTE
               && (a == MA_CLICK
#if MULTICLICK_ONLY_EVENT
                   || a == MA_2CLK || a == MA_3CLK
#endif
                   )) {
        request_paste(term->frontend);
    }

    term_update(term);
}

void term_nopaste(Terminal *term)
{
    if (term->paste_len == 0)
        return;
    sfree(term->paste_buffer);
    term->paste_buffer = NULL;
    term->paste_len = 0;
}

int term_paste_pending(Terminal *term)
{
    return term->paste_len != 0;
}

void term_paste(Terminal *term)
{
    long now, paste_diff;

    if (term->paste_len == 0)
        return;

    /* Don't wait forever to paste */
    if (term->paste_hold) {
        now = GETTICKCOUNT();
        paste_diff = now - term->last_paste;
        if (paste_diff >= 0 && paste_diff < 450)
            return;
    }
    term->paste_hold = 0;

    while (term->paste_pos < term->paste_len) {
        int n = 0;
        while (n + term->paste_pos < term->paste_len) {
            if (term->paste_buffer[term->paste_pos + n++] == '\015')
                break;
        }
        if (term->ldisc)
            luni_send(term->ldisc, term->paste_buffer + term->paste_pos, n, 0);
        term->paste_pos += n;

        if (term->paste_pos < term->paste_len) {
            term->paste_hold = 1;
            return;
        }
    }
    sfree(term->paste_buffer);
    term->paste_buffer = NULL;
    term->paste_len = 0;
}

static void deselect(Terminal *term)
{
    term->selstate = NO_SELECTION;
    term->selstart.x = term->selstart.y = term->selend.x = term->selend.y = 0;
}

void term_deselect(Terminal *term)
{
    deselect(term);
    term_update(term);
}

int term_ldisc(Terminal *term, int option)
{
    if (option == LD_ECHO)
        return term->term_echoing;
    if (option == LD_EDIT)
        return term->term_editing;
    return FALSE;
}

/*
 * from_backend(), to get data from the backend for the terminal.
 */
int from_backend(void *vterm, int is_stderr, char *data, int len)
{
    Terminal *term = (Terminal *)vterm;

    assert(len > 0);

    bufchain_add(&term->inbuf, data, len);

    /*
     * term_out() always completely empties inbuf. Therefore,
     * there's no reason at all to return anything other than zero
     * from this function, because there _can't_ be a question of
     * the remote side needing to wait until term_out() has cleared
     * a backlog.
     *
     * This is a slightly suboptimal way to deal with SSH2 - in
     * principle, the window mechanism would allow us to continue
     * to accept data on forwarded ports and X connections even
     * while the terminal processing was going slowly - but we
     * can't do the 100% right thing without moving the terminal
     * processing into a separate thread, and that might hurt
     * portability. So we manage stdout buffering the old SSH1 way:
     * if the terminal processing goes slowly, the whole SSH
     * connection stops accepting data until it's ready.
     *
     * In practice, I can't imagine this causing serious trouble.
     */
    return 0;
}

void term_provide_logctx(Terminal *term, void *logctx)
{
    term->logctx = logctx;
}