[sgt/charset] / iso2022.c

/*
 * iso2022.c - support for ISO/IEC 2022 (alias ECMA-35).
 *
 * This isn't a complete implementation of ISO/IEC 2022, but it's
 * close.  It only handles decoding, because a fully general encoder
 * isn't really useful.  It can decode 8-bit and 7-bit versions, with
 * support for single-byte and multi-byte character sets, all four
 * containers (G0, G1, G2, and G3), using both single-shift and
 * locking-shift sequences.
 *
 * The general principle is that any valid ISO/IEC 2022 sequence
 * should either be correctly decoded or should emit an ERROR.  The
 * only exception to this is that the C0 and C1 sets are fixed as
 * those of ISO/IEC 6429.  Escape sequences for designating control
 * sets are passed through, so a post-processor could fix them up if
 * necessary.
 *
 * DOCS is not currently supported.  It will be one day.
 */

#ifndef ENUM_CHARSETS

#include <assert.h>

#include "charset.h"
#include "internal.h"
#include "sbcsdat.h"

#define LS1 (0x0E)
#define LS0 (0x0F)
#define ESC (0x1B)
#define SS2 (0x8E)
#define SS3 (0x8F)

enum {S4, S6, M4, M6};

static long int null_dbcs_to_unicode(int, int);

const struct iso2022_subcharset {
    char type, i, f;
    int offset;
    const sbcs_data *sbcs_base;
    long int (*dbcs_fn)(int, int);
} iso2022_subcharsets[] = {
    { S4, 0, 'B', 0x00, &sbcsdata_CS_ASCII },

    { S4, 0, '<', 0x80, &sbcsdata_CS_DEC_MCS },
    { S4, 0, 'I', 0x80, &sbcsdata_CS_JISX0201 },
    { S4, 0, 'J', 0x00, &sbcsdata_CS_JISX0201 },
    { S4, 0, '~' },
    { S6, 0, 'A', 0x80, &sbcsdata_CS_ISO8859_1 },
    { S6, 0, 'B', 0x80, &sbcsdata_CS_ISO8859_2 },
    { S6, 0, 'C', 0x80, &sbcsdata_CS_ISO8859_3 },
    { S6, 0, 'D', 0x80, &sbcsdata_CS_ISO8859_4 },
    { S6, 0, 'F', 0x80, &sbcsdata_CS_ISO8859_7 },
    { S6, 0, 'G', 0x80, &sbcsdata_CS_ISO8859_6 },
    { S6, 0, 'H', 0x80, &sbcsdata_CS_ISO8859_8 },
    { S6, 0, 'L', 0x80, &sbcsdata_CS_ISO8859_5 },
    { S6, 0, 'M', 0x80, &sbcsdata_CS_ISO8859_9 },
    { S6, 0, 'T', 0x80, &sbcsdata_CS_ISO8859_11 },
    { S6, 0, 'V', 0x80, &sbcsdata_CS_ISO8859_10 },
    { S6, 0, 'Y', 0x80, &sbcsdata_CS_ISO8859_13 },
    { S6, 0, '_', 0x80, &sbcsdata_CS_ISO8859_14 },
    { S6, 0, 'b', 0x80, &sbcsdata_CS_ISO8859_15 },
    { S6, 0, 'f', 0x80, &sbcsdata_CS_ISO8859_16 },
    { S6, 0, '~' }, /* empty 96-set */
#if 0
    { M4, 0, '@' }, /* JIS C 6226-1978 */
#endif
    { M4, 0, 'A', -0x21, 0, &gb2312_to_unicode },
    { M4, 0, 'B', -0x21, 0, &jisx0208_to_unicode },
    { M4, 0, 'C', -0x21, 0, &ksx1001_to_unicode },
    { M4, 0, 'D', -0x21, 0, &jisx0212_to_unicode },
    { M4, 0, '~', 0, 0, &null_dbcs_to_unicode }, /* empty 94^n-set */
    { M6, 0, '~', 0, 0, &null_dbcs_to_unicode }, /* empty 96^n-set */
};

static long int null_dbcs_to_unicode(int r, int c)
{
    return ERROR;
}

/* States, or "what we're currently accumulating". */
enum {
    IDLE,	/* None of the below */
    SS2CHAR,	/* Accumulating a character after SS2 */
    SS3CHAR,	/* Accumulating a character after SS3 */
    ESCSEQ,	/* Accumulating an escape sequence */
    ESCDROP,	/* Discarding an escape sequence */
    ESCPASS	/* Passing through an escape sequence */
};

#if 0
#include <stdio.h>
static void dump_state(charset_state *s)
{
    unsigned s0 = s->s0, s1 = s->s1;
    char const * const modes[] = { "IDLE", "SS2CHAR", "SS3CHAR",
				   "ESCSEQ", "ESCDROP", "ESCPASS" };

    fprintf(stderr, "s0: %s", modes[s0 >> 29]);
    fprintf(stderr, " %02x %02x %02x   ", (s0 >> 16) & 0xff, (s0 >> 8) & 0xff,
	    s0 & 0xff);
    fprintf(stderr, "s1: LS%d LS%dR", (s1 >> 30) & 3, (s1 >> 28) & 3);
    fprintf(stderr, " %d %d %d %d\n", s1 & 0x7f, (s1 >> 7) & 0x7f,
	    (s1 >> 14) & 0x7f, (s1 >> 21) & 0x7f);
}
#endif

static void designate(charset_state *state, int container,
		      int type, int ibyte, int fbyte)
{
    unsigned long i;

    assert(container >= 0 && container <= 3);
    assert(type == S4 || type == S6 || type == M4 || type == M6);

    for (i = 0; i <= lenof(iso2022_subcharsets); i++) {
	if (iso2022_subcharsets[i].type == type &&
	    iso2022_subcharsets[i].i == ibyte &&
	    iso2022_subcharsets[i].f == fbyte) {
	    state->s1 &= ~(0x7fL << (container * 7));
	    state->s1 |= (i << (container * 7));
	    return;
	}
    }
    /*
     * If we don't find the charset, invoke the empty one, so we
     * output ERROR rather than garbage.
     */
    designate(state, container, type, 0, '~');
}

static void read_iso2022(charset_spec const *charset, long int input_chr,
			  charset_state *state,
			  void (*emit)(void *ctx, long int output),
			  void *emitctx)
{

/*    dump_state(state); */
    /*
     * We've got 64 bits of state to play with.
     *
     * Locking-shift state: 2 bits each GL/GR
     * Single-shift state: 2 bits
     * Charset designation state: n bits each G0/G1/G2/G3
     * MBCS/esc seq accumulation: 14 bits (assume max 4-byte sets)
     * MBCS state: 2 bits (off, ESC, GL, GR)
     * For no good reason, put long-term state in s1, short term in s0.
     *
     * s0[31:29] = state enum
     * s0[24:0] = accumulated bytes
     * s1[31:30] = GL locking-shift state
     * s1[29:28] = GR locking-shift state
     * s1[27:21] = G3 charset
     * s1[20:14] = G2 charset
     * s1[13:7] = G1 charset
     * s1[6:0] = G0 charset
     */

#define LEFT 30
#define RIGHT 28
#define LOCKING_SHIFT(n,side) \
	(state->s1 = (state->s1 & ~(3L<<(side))) | ((n ## L)<<(side)))
#define MODE ((state->s0 & 0xe0000000L) >> 29)
#define ENTER_MODE(m) (state->s0 = (state->s0 & ~0xe0000000L) | ((m)<<29))
#define SINGLE_SHIFT(n) ENTER_MODE(SS2CHAR - 2 + (n))
#define ASSERT_IDLE do {						\
	if (state->s0 != 0) emit(emitctx, ERROR);			\
	state->s0 = 0;							\
} while (0)

    if (state->s1 == 0) {
	/*
	 * Since there's no LS0R, this means we must just have started.
	 * Set up a sane initial state (LS0, LS1R, ASCII in G0/G1/G2/G3).
	 */
	LOCKING_SHIFT(0, LEFT);
	LOCKING_SHIFT(1, RIGHT);
	designate(state, 0, S4, 0, 'B');
	designate(state, 1, S4, 0, 'B');
	designate(state, 2, S4, 0, 'B');
	designate(state, 3, S4, 0, 'B');
    }

    if ((input_chr & 0x60) == 0x00) {
	/* C0 or C1 control */
	ASSERT_IDLE;
	switch (input_chr) {
	  case ESC:
	    ENTER_MODE(ESCSEQ);
	    break;
	  case LS0:
	    LOCKING_SHIFT(0, LEFT);
	    break;
	  case LS1:
	    LOCKING_SHIFT(1, LEFT);
	    break;
	  case SS2:
	    SINGLE_SHIFT(2);
	    break;
	  case SS3:
	    SINGLE_SHIFT(3);
	    break;
	  default:
	    emit(emitctx, input_chr);
	    break;
	}
    } else if ((input_chr & 0x80) || MODE < ESCSEQ) {
	int is_gl = 0;
	struct iso2022_subcharset const *subcs;
	unsigned container;
	long input_7bit;
	/*
	 * Actual data.
	 * Force idle state if we're in mid escape sequence, or in a
	 * multi-byte character with a different top bit.
	 */
	if (MODE >= ESCSEQ ||
	    ((state->s0 & 0x00ff0000L) != 0 && 
	     (((state->s0 >> 16) ^ input_chr) & 0x80)))
	    ASSERT_IDLE;
	if (MODE == SS2CHAR || MODE == SS3CHAR) /* Single-shift */
	    container = MODE - SS2CHAR + 2;
	else if (input_chr >= 0x80) /* GR */
	    container = (state->s1 >> 28) & 3;
	else { /* GL */
	    container = state->s1 >> 30;
	    is_gl = 1;
	}
	input_7bit = input_chr & ~0x80;
	subcs = &iso2022_subcharsets[(state->s1 >> (container * 7)) & 0x7f];
	if ((subcs->type == S4 || subcs->type == M4) &&
	    (input_7bit == 0x20 || input_7bit == 0x7f)) {
	    /* characters not in 94-char set */
	    if (is_gl) emit(emitctx, input_7bit);
	    else emit(emitctx, ERROR);
	} else if (subcs->type == M4 || subcs->type == M6) {
	    if ((state->s0 & 0x00ff0000L) == 0) {
		state->s0 |= input_chr << 16;
		return;
	    } else {
		emit(emitctx,
		     subcs->dbcs_fn(((state->s0 >> 16) & 0x7f) + subcs->offset,
				    input_7bit + subcs->offset));
	    }
	} else {
	    if ((state->s0 & 0x00ff0000L) != 0)
		emit(emitctx, ERROR);
	    emit(emitctx, subcs->sbcs_base ?
		 sbcs_to_unicode(subcs->sbcs_base, input_7bit + subcs->offset):
		 ERROR);
	}
	state->s0 = 0;
    } else {
	unsigned i1, i2;
	if (MODE == ESCPASS) {
	    emit(emitctx, input_chr);
	    if ((input_chr & 0xf0) != 0x20)
		ENTER_MODE(IDLE);
	    return;
	}

	/*
	 * Intermediate bytes shall be any of the 16 positions of
	 * column 02 of the code table; they are denoted by the symbol
	 * I.
	 */
	if ((input_chr & 0xf0) == 0x20) {
	    if (((state->s0 >> 16) & 0xff) == 0)
		state->s0 |= input_chr << 16;
	    else if (((state->s0 >> 8) & 0xff) == 0)
		state->s0 |= input_chr << 8;
	    else {
		/* Long escape sequence.  Switch to ESCPASS or ESCDROP. */
		i1 = (state->s0 >> 16) & 0xff;
		i2 = (state->s0 >> 8) & 0xff;
		switch (i1) {
		  case '(': case ')': case '*': case '+':
		  case '-': case '.': case '/':
		  case '$':
		    ENTER_MODE(ESCDROP);
		    break;
		  default:
		    emit(emitctx, ESC);
		    emit(emitctx, i1);
		    emit(emitctx, i2);
		    emit(emitctx, input_chr);
		    state->s0 = 0;
		    ENTER_MODE(ESCPASS);
		    break;
		}
	    }
	    return;
	}

	/*
	 * Final bytes shall be any of the 79 positions of columns 03
	 * to 07 of the code table excluding position 07/15; they are
	 * denoted by the symbol F.
	 */
	i1 = (state->s0 >> 16) & 0xff;
	i2 = (state->s0 >> 8) & 0xff;
	if (MODE == ESCDROP)
	    input_chr = 0; /* Make sure it won't match. */
	state->s0 = 0;
	switch (i1) {
	  case 0: /* No intermediate bytes */
	    switch (input_chr) {
	      case 'N': /* SS2 */
		SINGLE_SHIFT(2);
		break;
	      case 'O': /* SS3 */
		SINGLE_SHIFT(3);
		break;
	      case 'n': /* LS2 */
		LOCKING_SHIFT(2, LEFT);
		break;
	      case 'o': /* LS3 */
		LOCKING_SHIFT(3, LEFT);
		break;
	      case '|': /* LS3R */
		LOCKING_SHIFT(3, RIGHT);
		break;
	      case '}': /* LS2R */
		LOCKING_SHIFT(2, RIGHT);
		break;
	      case '~': /* LS1R */
		LOCKING_SHIFT(1, RIGHT);
		break;
	      default:
		/* Unsupported escape sequence.  Spit it back out. */
		emit(emitctx, ESC);
		emit(emitctx, input_chr);
	    }
	    break;
	  case ' ': /* ACS */
	    /*
	     * Various coding structure facilities specify that designating
	     * a code element also invokes it.  As far as I can see, invoking
	     * it now will have the same practical effect, since those
	     * facilities also ban the use of locking shifts.
	     */
	    switch (input_chr) {
	      case 'A': /* G0 element used and invoked into GL */
		LOCKING_SHIFT(0, LEFT);
		break;
	      case 'C': /* G0 in GL, G1 in GR */
	      case 'D': /* Ditto, at least for 8-bit codes */
	      case 'L': /* ISO 4873 (ECMA-43) level 1 */
	      case 'M': /* ISO 4873 (ECMA-43) level 2 */
		LOCKING_SHIFT(0, LEFT);
		LOCKING_SHIFT(1, RIGHT);
		break;
	    }
	    break;
	  case '&': /* IRR */
	    /*
	     * IRR (Identify Revised Registration) is ignored here,
	     * since any revised registration must be
	     * upward-compatible with the old one, so either we'll
	     * support the new one or we'll emit ERROR when we run
	     * into a new character.  In either case, there's nothing
	     * to be done here.
	     */
	    break;
	  case '(': /* GZD4 */  case ')': /* G1D4 */
	  case '*': /* G2D4 */  case '+': /* G3D4 */
	    designate(state, i1 - '(', S4, i2, input_chr);
	    break;
	  case '-': /* G1D6 */  case '.': /* G2D6 */  case '/': /* G3D6 */
	    designate(state, i1 - ',', S6, i2, input_chr);
	    break;
	  case '$': /* G?DM? */
	    switch (i2) {
	      case 0: /* Obsolete version of GZDM4 */
		i2 = '(';
	      case '(': /* GZDM4 */  case ')': /* G1DM4 */
	      case '*': /* G2DM4 */  case '+': /* G3DM4 */
		designate(state, i2 - '(', M4, 0, input_chr);
		break;
	      case '-': /* G1DM6 */
	      case '.': /* G2DM6 */  case '/': /* G3DM6 */
		designate(state, i2 - ',', M6, 0, input_chr);
		break;
	      default:
		emit(emitctx, ERROR);
		break;
	    }
	  case '%': /* DOCS */
	    /* FIXME */
	    break;
	  default:
	    /* Unsupported nF escape sequence.  Re-emit it. */
	    emit(emitctx, ESC);
	    emit(emitctx, i1);
	    if (i2) emit(emitctx, i2);
	    emit(emitctx, input_chr);
	    break;
	}
    }
}

const charset_spec charset_CS_ISO2022 = {
    CS_ISO2022, read_iso2022, NULL, NULL
};

#ifdef TESTMODE

#include <stdio.h>
#include <stdarg.h>
#include <string.h>

int total_errs = 0;

void iso2022_emit(void *ctx, long output)
{
    wchar_t **p = (wchar_t **)ctx;
    *(*p)++ = output;
}

void iso2022_read_test(int line, char *input, int inlen, ...)
{
    va_list ap;
    wchar_t *p, str[512];
    int i;
    charset_state state;
    unsigned long l;

    state.s0 = state.s1 = 0;
    p = str;

    for (i = 0; i < inlen; i++)
	read_iso2022(NULL, input[i] & 0xFF, &state, iso2022_emit, &p);

    va_start(ap, inlen);
    l = 0;
    for (i = 0; i < p - str; i++) {
	l = va_arg(ap, long int);
	if (l == -1) {
	    printf("%d: correct string shorter than output\n", line);
	    total_errs++;
	    break;
	}
	if (l != str[i]) {
	    printf("%d: char %d came out as %08x, should be %08lx\n",
		    line, i, str[i], l);
	    total_errs++;
	}
    }
    if (l != -1) {
	l = va_arg(ap, long int);
	if (l != -1) {
	    printf("%d: correct string longer than output\n", line);
	    total_errs++;
	}
    }
    va_end(ap);
}

/* Macro to concoct the first three parameters of iso2022_read_test. */
#define TESTSTR(x) __LINE__, x, lenof(x)

int main(void)
{
    printf("read tests beginning\n");
    /* Simple test (Emacs sample text for Japanese, in ISO-2022-JP) */
    iso2022_read_test(TESTSTR("Japanese (\x1b$BF|K\\8l\x1b(B)\t"
			      "\x1b$B$3$s$K$A$O\x1b(B, "
			      "\x1b$B%3%s%K%A%O\x1b(B\n"),
		      'J','a','p','a','n','e','s','e',' ','(',
		      0x65E5, 0x672C, 0x8A9E, ')', '\t',
		      0x3053, 0x3093, 0x306b, 0x3061, 0x306f, ',', ' ',
		      0x30b3, 0x30f3, 0x30cb, 0x30c1, 0x30cf, '\n', 0, -1);
    /* Same thing in EUC-JP (with designations, and half-width katakana) */
    iso2022_read_test(TESTSTR("\x1b$)B\x1b*I\x1b$+D"
			      "Japanese (\xc6\xfc\xcb\xdc\xb8\xec)\t"
			      "\xa4\xb3\xa4\xf3\xa4\xcb\xa4\xc1\xa4\xcf, "
			      "\x8e\xba\x8e\xdd\x8e\xc6\x8e\xc1\x8e\xca\n"),
		      'J','a','p','a','n','e','s','e',' ','(',
		      0x65E5, 0x672C, 0x8A9E, ')', '\t',
		      0x3053, 0x3093, 0x306b, 0x3061, 0x306f, ',', ' ',
		      0xff7a, 0xff9d, 0xff86, 0xff81, 0xff8a, '\n', 0, -1);
    /* Multibyte single-shift */
    iso2022_read_test(TESTSTR("\x1b$)B\x1b*I\x1b$+D\x8f\"/!"),
		      0x02D8, '!', 0, -1);
    /* Non-existent SBCS */
    iso2022_read_test(TESTSTR("\x1b(!Zfnord\n"),
		      ERROR, ERROR, ERROR, ERROR, ERROR, '\n', 0, -1);
    /* Pass-through of ordinary escape sequences, including a long one */
    iso2022_read_test(TESTSTR("\x1b""b\x1b#5\x1b#!!!5"),
		      0x1B, 'b', 0x1B, '#', '5',
		      0x1B, '#', '!', '!', '!', '5', 0, -1);
    /* Non-existent DBCS (also 5-byte escape sequence) */
    iso2022_read_test(TESTSTR("\x1b$(!Bfnord!"),
		      ERROR, ERROR, ERROR, 0, -1);
    /* Incomplete DB characters */
    iso2022_read_test(TESTSTR("\x1b$B(,(\x1b(BHi\x1b$B(,(\n"),
		      0x2501, ERROR, 'H', 'i', 0x2501, ERROR, '\n', 0, -1);
    iso2022_read_test(TESTSTR("\x1b$)B\x1b*I\x1b$+D\xa4""B"),
		      ERROR, 'B', 0, -1);
    iso2022_read_test(TESTSTR("\x1b$)B\x1b*I\x1b$+D\x0e\x1b|$\xa2\xaf"),
		      ERROR, 0x02D8, 0, -1);
    /* Incomplete escape sequence */
    iso2022_read_test(TESTSTR("\x1b\n"), ERROR, '\n', 0, -1);
    iso2022_read_test(TESTSTR("\x1b-A\x1b~\x1b\xa1"), ERROR, 0xa1, 0, -1);
    /* Incomplete single-shift */
    iso2022_read_test(TESTSTR("\x8e\n"), ERROR, '\n', 0, -1);
    iso2022_read_test(TESTSTR("\x1b$*B\x8e(\n"), ERROR, '\n', 0, -1);
    /* Corner cases (02/00 and 07/15) */
    iso2022_read_test(TESTSTR("\x1b(B\x20\x7f"), 0x20, 0x7f, 0, -1);
    iso2022_read_test(TESTSTR("\x1b(I\x20\x7f"), 0x20, 0x7f, 0, -1);
    iso2022_read_test(TESTSTR("\x1b$B\x20\x7f"), 0x20, 0x7f, 0, -1);
    iso2022_read_test(TESTSTR("\x1b-A\x0e\x20\x7f"), 0xa0, 0xff, 0, -1);
    iso2022_read_test(TESTSTR("\x1b$-~\x0e\x20\x7f"), ERROR, 0, -1);
    iso2022_read_test(TESTSTR("\x1b)B\xa0\xff"), ERROR, ERROR, 0, -1);
    iso2022_read_test(TESTSTR("\x1b)I\xa0\xff"), ERROR, ERROR, 0, -1);
    iso2022_read_test(TESTSTR("\x1b$)B\xa0\xff"), ERROR, ERROR, 0, -1);
    iso2022_read_test(TESTSTR("\x1b-A\x1b~\xa0\xff"), 0xa0, 0xff, 0, -1);
    iso2022_read_test(TESTSTR("\x1b$-~\x1b~\xa0\xff"), ERROR, 0, -1);
    /* Designate control sets */
    iso2022_read_test(TESTSTR("\x1b!@"), 0x1b, '!', '@', 0, -1);
    printf("read tests completed\n");
    printf("total: %d errors\n", total_errs);
    return (total_errs != 0);
}

#endif /* TESTMODE */

#else /* ENUM_CHARSETS */

ENUM_CHARSET(CS_ISO2022)

#endif
Commit	Line	Data
b97e5427	1	/*
	2	* iso2022.c - support for ISO/IEC 2022 (alias ECMA-35).
	3	*
	4	* This isn't a complete implementation of ISO/IEC 2022, but it's
	5	* close. It only handles decoding, because a fully general encoder
	6	* isn't really useful. It can decode 8-bit and 7-bit versions, with
	7	* support for single-byte and multi-byte character sets, all four
	8	* containers (G0, G1, G2, and G3), using both single-shift and
	9	* locking-shift sequences.
	10	*
	11	* The general principle is that any valid ISO/IEC 2022 sequence
	12	* should either be correctly decoded or should emit an ERROR. The
	13	* only exception to this is that the C0 and C1 sets are fixed as
	14	* those of ISO/IEC 6429. Escape sequences for designating control
	15	* sets are passed through, so a post-processor could fix them up if
	16	* necessary.
	17	*
	18	* DOCS is not currently supported. It will be one day.
	19	*/
	20
	21	#ifndef ENUM_CHARSETS
	22
	23	#include <assert.h>
	24
	25	#include "charset.h"
	26	#include "internal.h"
	27	#include "sbcsdat.h"
	28
	29	#define LS1 (0x0E)
	30	#define LS0 (0x0F)
	31	#define ESC (0x1B)
	32	#define SS2 (0x8E)
	33	#define SS3 (0x8F)
	34
	35	enum {S4, S6, M4, M6};
	36
	37	static long int null_dbcs_to_unicode(int, int);
	38
	39	const struct iso2022_subcharset {
	40	char type, i, f;
	41	int offset;
	42	const sbcs_data *sbcs_base;
	43	long int (*dbcs_fn)(int, int);
	44	} iso2022_subcharsets[] = {
	45	{ S4, 0, 'B', 0x00, &sbcsdata_CS_ASCII },
	46
	47	{ S4, 0, '<', 0x80, &sbcsdata_CS_DEC_MCS },
	48	{ S4, 0, 'I', 0x80, &sbcsdata_CS_JISX0201 },
	49	{ S4, 0, 'J', 0x00, &sbcsdata_CS_JISX0201 },
	50	{ S4, 0, '~' },
	51	{ S6, 0, 'A', 0x80, &sbcsdata_CS_ISO8859_1 },
	52	{ S6, 0, 'B', 0x80, &sbcsdata_CS_ISO8859_2 },
	53	{ S6, 0, 'C', 0x80, &sbcsdata_CS_ISO8859_3 },
	54	{ S6, 0, 'D', 0x80, &sbcsdata_CS_ISO8859_4 },
	55	{ S6, 0, 'F', 0x80, &sbcsdata_CS_ISO8859_7 },
	56	{ S6, 0, 'G', 0x80, &sbcsdata_CS_ISO8859_6 },
	57	{ S6, 0, 'H', 0x80, &sbcsdata_CS_ISO8859_8 },
	58	{ S6, 0, 'L', 0x80, &sbcsdata_CS_ISO8859_5 },
	59	{ S6, 0, 'M', 0x80, &sbcsdata_CS_ISO8859_9 },
	60	{ S6, 0, 'T', 0x80, &sbcsdata_CS_ISO8859_11 },
	61	{ S6, 0, 'V', 0x80, &sbcsdata_CS_ISO8859_10 },
	62	{ S6, 0, 'Y', 0x80, &sbcsdata_CS_ISO8859_13 },
	63	{ S6, 0, '_', 0x80, &sbcsdata_CS_ISO8859_14 },
	64	{ S6, 0, 'b', 0x80, &sbcsdata_CS_ISO8859_15 },
65	{ S6, 0, 'f', 0x80, &sbcsdata_CS_ISO8859_16 },
66	{ S6, 0, '~' }, /* empty 96-set */
67	#if 0
68	{ M4, 0, '@' }, /* JIS C 6226-1978 */
69	#endif
70	{ M4, 0, 'A', -0x21, 0, &gb2312_to_unicode },
71	{ M4, 0, 'B', -0x21, 0, &jisx0208_to_unicode },
72	{ M4, 0, 'C', -0x21, 0, &ksx1001_to_unicode },
73	{ M4, 0, 'D', -0x21, 0, &jisx0212_to_unicode },
74	{ M4, 0, '~', 0, 0, &null_dbcs_to_unicode }, /* empty 94^n-set */
75	{ M6, 0, '~', 0, 0, &null_dbcs_to_unicode }, /* empty 96^n-set */
76	};
77
78	static long int null_dbcs_to_unicode(int r, int c)
79	{
80	return ERROR;
81	}
82
83	/* States, or "what we're currently accumulating". */
84	enum {
85	IDLE, /* None of the below */
86	SS2CHAR, /* Accumulating a character after SS2 */
87	SS3CHAR, /* Accumulating a character after SS3 */
88	ESCSEQ, /* Accumulating an escape sequence */
89	ESCDROP, /* Discarding an escape sequence */
90	ESCPASS /* Passing through an escape sequence */
91	};
92
93	#if 0
94	#include <stdio.h>
95	static void dump_state(charset_state *s)
96	{
97	unsigned s0 = s->s0, s1 = s->s1;
98	char const * const modes[] = { "IDLE", "SS2CHAR", "SS3CHAR",
99	"ESCSEQ", "ESCDROP", "ESCPASS" };
100
101	fprintf(stderr, "s0: %s", modes[s0 >> 29]);
102	fprintf(stderr, " %02x %02x %02x ", (s0 >> 16) & 0xff, (s0 >> 8) & 0xff,
103	s0 & 0xff);
104	fprintf(stderr, "s1: LS%d LS%dR", (s1 >> 30) & 3, (s1 >> 28) & 3);
105	fprintf(stderr, " %d %d %d %d\n", s1 & 0x7f, (s1 >> 7) & 0x7f,
106	(s1 >> 14) & 0x7f, (s1 >> 21) & 0x7f);
107	}
108	#endif
109
110	static void designate(charset_state *state, int container,
111	int type, int ibyte, int fbyte)
112	{
113	unsigned long i;
114
115	assert(container >= 0 && container <= 3);
116	assert(type == S4 \|\| type == S6 \|\| type == M4 \|\| type == M6);
117
118	for (i = 0; i <= lenof(iso2022_subcharsets); i++) {
119	if (iso2022_subcharsets[i].type == type &&
120	iso2022_subcharsets[i].i == ibyte &&
121	iso2022_subcharsets[i].f == fbyte) {
122	state->s1 &= ~(0x7fL << (container * 7));
123	state->s1 \|= (i << (container * 7));
124	return;
125	}
126	}
127	/*
128	* If we don't find the charset, invoke the empty one, so we
129	* output ERROR rather than garbage.
130	*/
131	designate(state, container, type, 0, '~');
132	}
133
134	static void read_iso2022(charset_spec const *charset, long int input_chr,
135	charset_state *state,
136	void (emit)(void ctx, long int output),
137	void *emitctx)
138	{
139
140	/* dump_state(state); */
141	/*
142	* We've got 64 bits of state to play with.
143	*
144	* Locking-shift state: 2 bits each GL/GR
145	* Single-shift state: 2 bits
146	* Charset designation state: n bits each G0/G1/G2/G3
147	* MBCS/esc seq accumulation: 14 bits (assume max 4-byte sets)
148	* MBCS state: 2 bits (off, ESC, GL, GR)
149	* For no good reason, put long-term state in s1, short term in s0.
150	*
151	* s0[31:29] = state enum
152	* s0[24:0] = accumulated bytes
153	* s1[31:30] = GL locking-shift state
154	* s1[29:28] = GR locking-shift state
155	* s1[27:21] = G3 charset
156	* s1[20:14] = G2 charset
157	* s1[13:7] = G1 charset
158	* s1[6:0] = G0 charset
159	*/
160
161	#define LEFT 30
162	#define RIGHT 28
163	#define LOCKING_SHIFT(n,side) \
164	(state->s1 = (state->s1 & ~(3L<<(side))) \| ((n ## L)<<(side)))
165	#define MODE ((state->s0 & 0xe0000000L) >> 29)
166	#define ENTER_MODE(m) (state->s0 = (state->s0 & ~0xe0000000L) \| ((m)<<29))
167	#define SINGLE_SHIFT(n) ENTER_MODE(SS2CHAR - 2 + (n))
168	#define ASSERT_IDLE do { \
169	if (state->s0 != 0) emit(emitctx, ERROR); \
170	state->s0 = 0; \
171	} while (0)
172
173	if (state->s1 == 0) {
174	/*
175	* Since there's no LS0R, this means we must just have started.
176	* Set up a sane initial state (LS0, LS1R, ASCII in G0/G1/G2/G3).
177	*/
178	LOCKING_SHIFT(0, LEFT);
179	LOCKING_SHIFT(1, RIGHT);
180	designate(state, 0, S4, 0, 'B');
181	designate(state, 1, S4, 0, 'B');
182	designate(state, 2, S4, 0, 'B');
183	designate(state, 3, S4, 0, 'B');
184	}
185
186	if ((input_chr & 0x60) == 0x00) {
187	/* C0 or C1 control */
188	ASSERT_IDLE;
189	switch (input_chr) {
190	case ESC:
191	ENTER_MODE(ESCSEQ);
192	break;
193	case LS0:
194	LOCKING_SHIFT(0, LEFT);
195	break;
196	case LS1:
197	LOCKING_SHIFT(1, LEFT);
198	break;
199	case SS2:
200	SINGLE_SHIFT(2);
201	break;
202	case SS3:
203	SINGLE_SHIFT(3);
204	break;
205	default:
206	emit(emitctx, input_chr);
207	break;
208	}
209	} else if ((input_chr & 0x80) \|\| MODE < ESCSEQ) {
210	int is_gl = 0;
211	struct iso2022_subcharset const *subcs;
212	unsigned container;
213	long input_7bit;
214	/*
215	* Actual data.
216	* Force idle state if we're in mid escape sequence, or in a
217	* multi-byte character with a different top bit.
218	*/
219	if (MODE >= ESCSEQ \|\|
220	((state->s0 & 0x00ff0000L) != 0 &&
221	(((state->s0 >> 16) ^ input_chr) & 0x80)))
222	ASSERT_IDLE;
223	if (MODE == SS2CHAR \|\| MODE == SS3CHAR) /* Single-shift */
224	container = MODE - SS2CHAR + 2;
225	else if (input_chr >= 0x80) /* GR */
226	container = (state->s1 >> 28) & 3;
227	else { /* GL */
228	container = state->s1 >> 30;
229	is_gl = 1;
230	}
231	input_7bit = input_chr & ~0x80;
232	subcs = &iso2022_subcharsets[(state->s1 >> (container * 7)) & 0x7f];
233	if ((subcs->type == S4 \|\| subcs->type == M4) &&
234	(input_7bit == 0x20 \|\| input_7bit == 0x7f)) {
235	/* characters not in 94-char set */
236	if (is_gl) emit(emitctx, input_7bit);
237	else emit(emitctx, ERROR);
238	} else if (subcs->type == M4 \|\| subcs->type == M6) {
239	if ((state->s0 & 0x00ff0000L) == 0) {
240	state->s0 \|= input_chr << 16;
241	return;
242	} else {
243	emit(emitctx,
244	subcs->dbcs_fn(((state->s0 >> 16) & 0x7f) + subcs->offset,
245	input_7bit + subcs->offset));
246	}
247	} else {
248	if ((state->s0 & 0x00ff0000L) != 0)
249	emit(emitctx, ERROR);
250	emit(emitctx, subcs->sbcs_base ?
251	sbcs_to_unicode(subcs->sbcs_base, input_7bit + subcs->offset):
252	ERROR);
253	}
254	state->s0 = 0;
255	} else {
256	unsigned i1, i2;
257	if (MODE == ESCPASS) {
258	emit(emitctx, input_chr);
259	if ((input_chr & 0xf0) != 0x20)
260	ENTER_MODE(IDLE);
261	return;
262	}
263
264	/*
265	* Intermediate bytes shall be any of the 16 positions of
266	* column 02 of the code table; they are denoted by the symbol
267	* I.
268	*/
269	if ((input_chr & 0xf0) == 0x20) {
270	if (((state->s0 >> 16) & 0xff) == 0)
271	state->s0 \|= input_chr << 16;
272	else if (((state->s0 >> 8) & 0xff) == 0)
273	state->s0 \|= input_chr << 8;
274	else {
275	/* Long escape sequence. Switch to ESCPASS or ESCDROP. */
276	i1 = (state->s0 >> 16) & 0xff;
277	i2 = (state->s0 >> 8) & 0xff;
278	switch (i1) {
279	case '(': case ')': case '*': case '+':
280	case '-': case '.': case '/':
281	case '$':
282	ENTER_MODE(ESCDROP);
283	break;
284	default:
285	emit(emitctx, ESC);
286	emit(emitctx, i1);
287	emit(emitctx, i2);
288	emit(emitctx, input_chr);
289	state->s0 = 0;
290	ENTER_MODE(ESCPASS);
291	break;
292	}
293	}
294	return;
295	}
296
297	/*
298	* Final bytes shall be any of the 79 positions of columns 03
299	* to 07 of the code table excluding position 07/15; they are
300	* denoted by the symbol F.
301	*/
302	i1 = (state->s0 >> 16) & 0xff;
303	i2 = (state->s0 >> 8) & 0xff;
304	if (MODE == ESCDROP)
305	input_chr = 0; /* Make sure it won't match. */
306	state->s0 = 0;
307	switch (i1) {
308	case 0: /* No intermediate bytes */
309	switch (input_chr) {
310	case 'N': /* SS2 */
311	SINGLE_SHIFT(2);
312	break;
313	case 'O': /* SS3 */
314	SINGLE_SHIFT(3);
315	break;
316	case 'n': /* LS2 */
317	LOCKING_SHIFT(2, LEFT);
318	break;
319	case 'o': /* LS3 */
320	LOCKING_SHIFT(3, LEFT);
321	break;
322	case '\|': /* LS3R */
323	LOCKING_SHIFT(3, RIGHT);
324	break;
325	case '}': /* LS2R */
326	LOCKING_SHIFT(2, RIGHT);
327	break;
328	case '~': /* LS1R */
329	LOCKING_SHIFT(1, RIGHT);
330	break;
331	default:
332	/* Unsupported escape sequence. Spit it back out. */
333	emit(emitctx, ESC);
334	emit(emitctx, input_chr);
335	}
336	break;
337	case ' ': /* ACS */
338	/*
339	* Various coding structure facilities specify that designating
340	* a code element also invokes it. As far as I can see, invoking
341	* it now will have the same practical effect, since those
342	* facilities also ban the use of locking shifts.
343	*/
344	switch (input_chr) {
345	case 'A': /* G0 element used and invoked into GL */
346	LOCKING_SHIFT(0, LEFT);
347	break;
348	case 'C': /* G0 in GL, G1 in GR */
349	case 'D': /* Ditto, at least for 8-bit codes */
350	case 'L': /* ISO 4873 (ECMA-43) level 1 */
351	case 'M': /* ISO 4873 (ECMA-43) level 2 */
352	LOCKING_SHIFT(0, LEFT);
353	LOCKING_SHIFT(1, RIGHT);
354	break;
355	}
356	break;
357	case '&': /* IRR */
358	/*
359	* IRR (Identify Revised Registration) is ignored here,
360	* since any revised registration must be
361	* upward-compatible with the old one, so either we'll
362	* support the new one or we'll emit ERROR when we run
363	* into a new character. In either case, there's nothing
364	* to be done here.
365	*/
366	break;
367	case '(': /* GZD4 / case ')': / G1D4 */
368	case '': / G2D4 / case '+': / G3D4 */
369	designate(state, i1 - '(', S4, i2, input_chr);
370	break;
371	case '-': /* G1D6 / case '.': / G2D6 / case '/': / G3D6 */
372	designate(state, i1 - ',', S6, i2, input_chr);
373	break;
374	case '$': /* G?DM? */
375	switch (i2) {
376	case 0: /* Obsolete version of GZDM4 */
377	i2 = '(';
378	case '(': /* GZDM4 / case ')': / G1DM4 */
379	case '': / G2DM4 / case '+': / G3DM4 */
380	designate(state, i2 - '(', M4, 0, input_chr);
381	break;
382	case '-': /* G1DM6 */
383	case '.': /* G2DM6 / case '/': / G3DM6 */
384	designate(state, i2 - ',', M6, 0, input_chr);
385	break;
386	default:
387	emit(emitctx, ERROR);
388	break;
389	}
390	case '%': /* DOCS */
391	/* FIXME */
392	break;
393	default:
394	/* Unsupported nF escape sequence. Re-emit it. */
395	emit(emitctx, ESC);
396	emit(emitctx, i1);
397	if (i2) emit(emitctx, i2);
398	emit(emitctx, input_chr);
399	break;
400	}
401	}
402	}
403
404	const charset_spec charset_CS_ISO2022 = {
405	CS_ISO2022, read_iso2022, NULL, NULL
406	};
407
408	#ifdef TESTMODE
409
410	#include <stdio.h>
411	#include <stdarg.h>
412	#include <string.h>
413
414	int total_errs = 0;
415
416	void iso2022_emit(void *ctx, long output)
417	{
418	wchar_t p = (wchar_t )ctx;
419	(p)++ = output;
420	}
421
422	void iso2022_read_test(int line, char *input, int inlen, ...)
423	{
424	va_list ap;
425	wchar_t *p, str[512];
426	int i;
427	charset_state state;
428	unsigned long l;
429
430	state.s0 = state.s1 = 0;
431	p = str;
432
433	for (i = 0; i < inlen; i++)
434	read_iso2022(NULL, input[i] & 0xFF, &state, iso2022_emit, &p);
435
436	va_start(ap, inlen);
437	l = 0;
438	for (i = 0; i < p - str; i++) {
439	l = va_arg(ap, long int);
440	if (l == -1) {
441	printf("%d: correct string shorter than output\n", line);
442	total_errs++;
443	break;
444	}
445	if (l != str[i]) {
446	printf("%d: char %d came out as %08x, should be %08lx\n",
447	line, i, str[i], l);
448	total_errs++;
449	}
450	}
451	if (l != -1) {
452	l = va_arg(ap, long int);
453	if (l != -1) {
454	printf("%d: correct string longer than output\n", line);
455	total_errs++;
456	}
457	}
458	va_end(ap);
459	}
460
461	/* Macro to concoct the first three parameters of iso2022_read_test. */
462	#define TESTSTR(x) __LINE__, x, lenof(x)
463
464	int main(void)
465	{
466	printf("read tests beginning\n");
467	/* Simple test (Emacs sample text for Japanese, in ISO-2022-JP) */
468	iso2022_read_test(TESTSTR("Japanese (\x1b$BF\|K\\8l\x1b(B)\t"
469	"\x1b$B$3$s$K$A$O\x1b(B, "
470	"\x1b$B%3%s%K%A%O\x1b(B\n"),
471	'J','a','p','a','n','e','s','e',' ','(',
472	0x65E5, 0x672C, 0x8A9E, ')', '\t',
473	0x3053, 0x3093, 0x306b, 0x3061, 0x306f, ',', ' ',
474	0x30b3, 0x30f3, 0x30cb, 0x30c1, 0x30cf, '\n', 0, -1);
475	/* Same thing in EUC-JP (with designations, and half-width katakana) */
476	iso2022_read_test(TESTSTR("\x1b$)B\x1b*I\x1b$+D"
477	"Japanese (\xc6\xfc\xcb\xdc\xb8\xec)\t"
478	"\xa4\xb3\xa4\xf3\xa4\xcb\xa4\xc1\xa4\xcf, "
479	"\x8e\xba\x8e\xdd\x8e\xc6\x8e\xc1\x8e\xca\n"),
480	'J','a','p','a','n','e','s','e',' ','(',
481	0x65E5, 0x672C, 0x8A9E, ')', '\t',
482	0x3053, 0x3093, 0x306b, 0x3061, 0x306f, ',', ' ',
483	0xff7a, 0xff9d, 0xff86, 0xff81, 0xff8a, '\n', 0, -1);
484	/* Multibyte single-shift */
485	iso2022_read_test(TESTSTR("\x1b$)B\x1b*I\x1b$+D\x8f\"/!"),
486	0x02D8, '!', 0, -1);
487	/* Non-existent SBCS */
488	iso2022_read_test(TESTSTR("\x1b(!Zfnord\n"),
489	ERROR, ERROR, ERROR, ERROR, ERROR, '\n', 0, -1);
490	/* Pass-through of ordinary escape sequences, including a long one */
491	iso2022_read_test(TESTSTR("\x1b""b\x1b#5\x1b#!!!5"),
492	0x1B, 'b', 0x1B, '#', '5',
493	0x1B, '#', '!', '!', '!', '5', 0, -1);
494	/* Non-existent DBCS (also 5-byte escape sequence) */
495	iso2022_read_test(TESTSTR("\x1b$(!Bfnord!"),
496	ERROR, ERROR, ERROR, 0, -1);
497	/* Incomplete DB characters */
498	iso2022_read_test(TESTSTR("\x1b$B(,(\x1b(BHi\x1b$B(,(\n"),
499	0x2501, ERROR, 'H', 'i', 0x2501, ERROR, '\n', 0, -1);
500	iso2022_read_test(TESTSTR("\x1b$)B\x1b*I\x1b$+D\xa4""B"),
501	ERROR, 'B', 0, -1);
502	iso2022_read_test(TESTSTR("\x1b$)B\x1b*I\x1b$+D\x0e\x1b\|$\xa2\xaf"),
503	ERROR, 0x02D8, 0, -1);
504	/* Incomplete escape sequence */
505	iso2022_read_test(TESTSTR("\x1b\n"), ERROR, '\n', 0, -1);
506	iso2022_read_test(TESTSTR("\x1b-A\x1b~\x1b\xa1"), ERROR, 0xa1, 0, -1);
507	/* Incomplete single-shift */
508	iso2022_read_test(TESTSTR("\x8e\n"), ERROR, '\n', 0, -1);
509	iso2022_read_test(TESTSTR("\x1b$*B\x8e(\n"), ERROR, '\n', 0, -1);
510	/* Corner cases (02/00 and 07/15) */
511	iso2022_read_test(TESTSTR("\x1b(B\x20\x7f"), 0x20, 0x7f, 0, -1);
512	iso2022_read_test(TESTSTR("\x1b(I\x20\x7f"), 0x20, 0x7f, 0, -1);
513	iso2022_read_test(TESTSTR("\x1b$B\x20\x7f"), 0x20, 0x7f, 0, -1);
514	iso2022_read_test(TESTSTR("\x1b-A\x0e\x20\x7f"), 0xa0, 0xff, 0, -1);
515	iso2022_read_test(TESTSTR("\x1b$-~\x0e\x20\x7f"), ERROR, 0, -1);
516	iso2022_read_test(TESTSTR("\x1b)B\xa0\xff"), ERROR, ERROR, 0, -1);
517	iso2022_read_test(TESTSTR("\x1b)I\xa0\xff"), ERROR, ERROR, 0, -1);
518	iso2022_read_test(TESTSTR("\x1b$)B\xa0\xff"), ERROR, ERROR, 0, -1);
519	iso2022_read_test(TESTSTR("\x1b-A\x1b~\xa0\xff"), 0xa0, 0xff, 0, -1);
520	iso2022_read_test(TESTSTR("\x1b$-~\x1b~\xa0\xff"), ERROR, 0, -1);
521	/* Designate control sets */
522	iso2022_read_test(TESTSTR("\x1b!@"), 0x1b, '!', '@', 0, -1);
523	printf("read tests completed\n");
524	printf("total: %d errors\n", total_errs);
525	return (total_errs != 0);
526	}
527
528	#endif /* TESTMODE */
529
530	#else /* ENUM_CHARSETS */
531
532	ENUM_CHARSET(CS_ISO2022)
533
534	#endif