Info backend now takes care to avoid magic characters in node names

[sgt/halibut] / index.c

/*
 * index.c: create and collate index data structures
 */

#include <stdio.h>
#include <stdlib.h>
#include "halibut.h"

static int compare_tags(void *av, void *bv);
static int compare_entries(void *av, void *bv);

indexdata *make_index(void) {
    indexdata *ret = mknew(indexdata);
    ret->tags = newtree234(compare_tags);
    ret->entries = newtree234(compare_entries);
    return ret;
}

static indextag *make_indextag(void) {
    indextag *ret = mknew(indextag);
    ret->name = NULL;
    ret->implicit_text = NULL;
    ret->explicit_texts = NULL;
    ret->explicit_fpos = NULL;
    ret->nexplicit = ret->explicit_size = ret->nrefs = 0;
    ret->refs = NULL;
    return ret;
}

static int compare_tags(void *av, void *bv) {
    indextag *a = (indextag *)av, *b = (indextag *)bv;
    return ustricmp(a->name, b->name);
}

static int compare_to_find_tag(void *av, void *bv) {
    wchar_t *a = (wchar_t *)av;
    indextag *b = (indextag *)bv;
    return ustricmp(a, b->name);
}

static int compare_entries(void *av, void *bv) {
    indexentry *a = (indexentry *)av, *b = (indexentry *)bv;
    return compare_wordlists(a->text, b->text);    
}

/*
 * Back-end utility: find the indextag with a given name.
 */
indextag *index_findtag(indexdata *idx, wchar_t *name) {
    return find234(idx->tags, name, compare_to_find_tag);
}

/*
 * Add a \IM. `tags' points to a zero-terminated chain of
 * zero-terminated strings ("first\0second\0thirdandlast\0\0").
 * `text' points to a word list.
 *
 * Guarantee on calling sequence: all implicit merges are given
 * before the explicit ones.
 */
void index_merge(indexdata *idx, int is_explicit, wchar_t *tags, word *text,
                 filepos *fpos) {
    indextag *t, *existing;

    /*
     * For an implicit merge, we want to remove all emphasis,
     * because the chances are that the user didn't really want to
     * index the term as emphasised.
     */
    {
        word *w;

        for (w = text; w; w = w->next) {
            if (w->type == word_Emph)
                w->type = word_Normal;
            else if (w->type == word_EmphSpace)
                w->type = word_WhiteSpace;
            else if (w->type == word_EmphQuote)
                w->type = word_Quote;
        }
    }

    /*
     * FIXME: want to warn on overlapping source sets.
     */
    for (; *tags; tags = uadv(tags)) {
        t = make_indextag();
        t->name = tags;
        existing = add234(idx->tags, t);
        if (existing == t) {
            /*
             * Duplicate this so we can free it independently.
             */
            t->name = ustrdup(tags);

            /*
             * Every tag has an implicit \IM. So if this tag
             * doesn't exist and we're explicit, then we should
             * warn (and drop it, since it won't be referenced).
             */
            if (is_explicit) {
                error(err_nosuchidxtag, tags);
                continue;
            }

            /*
             * Otherwise, this is a new tag with an implicit \IM.
             */
            t->implicit_text = text;
            t->implicit_fpos = *fpos;
        } else {
            sfree(t);
            t = existing;
            if (!is_explicit) {
                /*
                 * An implicit \IM for a tag that's had an implicit
                 * \IM before. FIXME: we should check the text
                 * against the existing text and warn on
                 * differences. And check the tag for case match
                 * against the existing tag, likewise.
                 */
            } else {
                /*
                 * An explicit \IM added to a valid tag. In
                 * particular, this removes the implicit \IM if
                 * present.
                 */
                if (t->implicit_text) {
                    free_word_list(t->implicit_text);
                    t->implicit_text = NULL;
                }
                if (t->nexplicit >= t->explicit_size) {
                    t->explicit_size = t->nexplicit + 8;
                    t->explicit_texts = resize(t->explicit_texts,
                                               t->explicit_size);
                    t->explicit_fpos = resize(t->explicit_fpos,
                                              t->explicit_size);
                }
                t->explicit_texts[t->nexplicit] = text;
                t->explicit_fpos[t->nexplicit] = *fpos;
                t->nexplicit++;
            }
        }
    }
}

/*
 * Build the final-form index. We now have every tag, with every
 * \IM, set up in a 2-3 tree indexed by tag. We now want to collate
 * the RHSes of the \IMs, and sort by final form, and decorate the
 * entries in the original 2-3 tree with pointers to the RHS
 * entries.
 */
void build_index(indexdata *i) {
    indextag *t;
    word **ta;
    filepos *fa;
    int ti;
    int j;

    for (ti = 0; (t = (indextag *)index234(i->tags, ti)) != NULL; ti++) {
        if (t->implicit_text) {
            t->nrefs = 1;
            ta = &t->implicit_text;
            fa = &t->implicit_fpos;
        } else {
            t->nrefs = t->nexplicit;
            ta = t->explicit_texts;
            fa = t->explicit_fpos;
        }
        if (t->nrefs) {
            t->refs = mknewa(indexentry *, t->nrefs);
            for (j = 0; j < t->nrefs; j++) {
                indexentry *ent = mknew(indexentry);
                ent->text = *ta++;
                ent->fpos = *fa++;
                t->refs[j] = add234(i->entries, ent);
                if (t->refs[j] != ent)     /* duplicate */
                    sfree(ent);
            }
        }
    }
}

void cleanup_index(indexdata *i) {
    indextag *t;
    indexentry *ent;
    int ti;

    for (ti = 0; (t = (indextag *)index234(i->tags, ti)) != NULL; ti++) {
        sfree(t->name);
        free_word_list(t->implicit_text);
        sfree(t->explicit_texts);
        sfree(t->refs);
        sfree(t);
    }
    freetree234(i->tags);
    for (ti = 0; (ent = (indexentry *)index234(i->entries, ti))!=NULL; ti++) {
        sfree(ent);
    }
    freetree234(i->entries);
    sfree(i);
}

static void dbg_prtwordlist(int level, word *w);
static void dbg_prtmerge(int is_explicit, wchar_t *tag, word *text);

void index_debug(indexdata *i) {
    indextag *t;
    indexentry *y;
    int ti;
    int j;

    printf("\nINDEX TAGS\n==========\n\n");
    for (ti = 0; (t = (indextag *)index234(i->tags, ti)) != NULL; ti++) {
        printf("\n");
        if (t->implicit_text)
            dbg_prtmerge(0, t->name, t->implicit_text);
        for (j = 0; j < t->nexplicit; j++)
            dbg_prtmerge(1, t->name, t->explicit_texts[j]);
    }

    printf("\nINDEX ENTRIES\n=============\n\n");
    for (ti = 0; (y = (indexentry *)index234(i->entries, ti)) != NULL; ti++) {
        printf("\n");
        printf("{\n");
        dbg_prtwordlist(1, y->text);
        printf("}\n");
    }
}

static void dbg_prtmerge(int is_explicit, wchar_t *tag, word *text) {
    printf("\\IM: %splicit: \"", is_explicit ? "ex" : "im");
    for (; *tag; tag++)
        putchar(*tag);
    printf("\" {\n");
    dbg_prtwordlist(1, text);
    printf("}\n");
}

static void dbg_prtwordlist(int level, word *w) {
    for (; w; w = w->next) {
        wchar_t *wp;
        printf("%*sword %d ", level*4, "", w->type);
        if (w->text) {
            printf("\"");
            for (wp = w->text; *wp; wp++)
                    putchar(*wp);
            printf("\"");
        } else
            printf("(no text)");
        if (w->alt) {
            printf(" alt = {\n");
            dbg_prtwordlist(level+1, w->alt);
            printf("%*s}", level*4, "");
        }
        printf("\n");
    }
}