[mandoc.git] / chars.c

/*      $Id: chars.c,v 1.24 2010/07/26 13:59:00 kristaps Exp $ */
/*
 * Copyright (c) 2009 Kristaps Dzonsons <kristaps@bsd.lv>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "mandoc.h"
#include "chars.h"

#define PRINT_HI         126
#define PRINT_LO         32

struct  ln {
        struct ln        *next;
        const char       *code;
        const char       *ascii;
        int               unicode;
        int               type;
#define CHARS_CHAR       (1 << 0)
#define CHARS_STRING     (1 << 1)
#define CHARS_BOTH       (CHARS_CHAR | CHARS_STRING)
};

#define LINES_MAX         370

#define CHAR(in, ch, code) \
        { NULL, (in), (ch), (code), CHARS_CHAR },
#define STRING(in, ch, code) \
        { NULL, (in), (ch), (code), CHARS_STRING },
#define BOTH(in, ch, code) \
        { NULL, (in), (ch), (code), CHARS_BOTH },

#define CHAR_TBL_START    static struct ln lines[LINES_MAX] = {
#define CHAR_TBL_END      };

#include "chars.in"

struct  tbl {
        enum chars        type;
        struct ln       **htab;
};

static  inline int        match(const struct ln *,
                                const char *, size_t, int);
static  const struct ln  *find(struct tbl *, const char *, size_t, int);


void
chars_free(void *arg)
{
        struct tbl      *tab;

        tab = (struct tbl *)arg;

        free(tab->htab);
        free(tab);
}


void *
chars_init(enum chars type)
{
        struct tbl       *tab;
        struct ln       **htab;
        struct ln        *pp;
        int               i, hash;

        /*
         * Constructs a very basic chaining hashtable.  The hash routine
         * is simply the integral value of the first character.
         * Subsequent entries are chained in the order they're processed
         * (they're in-line re-ordered during lookup).
         */

        tab = malloc(sizeof(struct tbl));
        if (NULL == tab) {
                perror(NULL);
                exit(EXIT_FAILURE);
        }

        htab = calloc(PRINT_HI - PRINT_LO + 1, sizeof(struct ln **));
        if (NULL == htab) {
                perror(NULL);
                exit(EXIT_FAILURE);
        }

        for (i = 0; i < LINES_MAX; i++) {
                hash = (int)lines[i].code[0] - PRINT_LO;

                if (NULL == (pp = htab[hash])) {
                        htab[hash] = &lines[i];
                        continue;
                }

                for ( ; pp->next; pp = pp->next)
                        /* Scan ahead. */ ;
                pp->next = &lines[i];
        }

        tab->htab = htab;
        tab->type = type;
        return(tab);
}


/* 
 * Special character to Unicode codepoint.
 */
int
chars_spec2cp(void *arg, const char *p, size_t sz)
{
        const struct ln *ln;

        ln = find((struct tbl *)arg, p, sz, CHARS_CHAR);
        if (NULL == ln)
                return(-1);
        return(ln->unicode);
}


/* 
 * Reserved word to Unicode codepoint.
 */
int
chars_res2cp(void *arg, const char *p, size_t sz)
{
        const struct ln *ln;

        ln = find((struct tbl *)arg, p, sz, CHARS_STRING);
        if (NULL == ln)
                return(-1);
        return(ln->unicode);
}


/* 
 * Special character to string array.
 */
const char *
chars_spec2str(void *arg, const char *p, size_t sz, size_t *rsz)
{
        const struct ln *ln;

        ln = find((struct tbl *)arg, p, sz, CHARS_CHAR);
        if (NULL == ln)
                return(NULL);

        *rsz = strlen(ln->ascii);
        return(ln->ascii);
}


/* 
 * Reserved word to string array.
 */
const char *
chars_res2str(void *arg, const char *p, size_t sz, size_t *rsz)
{
        const struct ln *ln;

        ln = find((struct tbl *)arg, p, sz, CHARS_STRING);
        if (NULL == ln)
                return(NULL);

        *rsz = strlen(ln->ascii);
        return(ln->ascii);
}


static const struct ln *
find(struct tbl *tab, const char *p, size_t sz, int type)
{
        struct ln        *pp, *prev;
        struct ln       **htab;
        int               hash;

        assert(p);
        if (0 == sz)
                return(NULL);

        if (p[0] < PRINT_LO || p[0] > PRINT_HI)
                return(NULL);

        /*
         * Lookup the symbol in the symbol hash.  See ascii2htab for the
         * hashtable specs.  This dynamically re-orders the hash chain
         * to optimise for repeat hits.
         */

        hash = (int)p[0] - PRINT_LO;
        htab = tab->htab;

        if (NULL == (pp = htab[hash]))
                return(NULL);

        for (prev = NULL; pp; pp = pp->next) {
                if ( ! match(pp, p, sz, type)) {
                        prev = pp;
                        continue;
                }

                if (prev) {
                        prev->next = pp->next;
                        pp->next = htab[hash];
                        htab[hash] = pp;
                }

                return(pp);
        }

        return(NULL);
}


static inline int
match(const struct ln *ln, const char *p, size_t sz, int type)
{

        if ( ! (ln->type & type))
                return(0);
        if (strncmp(ln->code, p, sz))
                return(0);
        return('\0' == ln->code[(int)sz]);
}