tcregex.c

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/*
 * finflect - Algorithms and tools for inflecting Finnish nouns
 * Copyright (C) 2004, 2005  The FinFlect Team
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 * 
 * For the complete legal text of the GNU Lesser General Public License,
 * see the file LICENSE. For a complete list of authors and copyright
 * holders, see the file AUTHORS.
 */

/**
 * @file tcregex.c Regex substitution implementation from tclib.
 */
 
/*
    Copyright (C) 2003  Michael Ahlberg, Måns Rullgård
 
    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
    files (the "Software"), to deal in the Software without
    restriction, including without limitation the rights to use, copy,
    modify, merge, publish, distribute, sublicense, and/or sell copies
    of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:
 
    The above copyright notice and this permission notice shall be
    included in all copies or substantial portions of the Software.
 
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
**/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
/*#include <tcstring.h>
#include <tctypes.h>*/
#include <regex.h>

#include "tcrip.h"

typedef struct regsub
{
  regex_t rx;
  regmatch_t *m;
  const char *s;
}
regsub_t;

static char *rs_lookup(char *n, void *d)
{
  regsub_t *rs = d;
  char *t;
  int ml;
  unsigned int m = strtol(n, &t, 0);

  if(*t)
    return NULL;
  if(m > rs->rx.re_nsub)
    return NULL;
  if(rs->m[m].rm_so < 0)
    return strdup("");

  ml = rs->m[m].rm_eo - rs->m[m].rm_so;
  t = malloc(ml + 1);
  strncpy(t, rs->s + rs->m[m].rm_so, ml);
  t[ml] = 0;

  return t;
}

char* tcregsub(const char *str, const char *pat, const char *sub, int cflags)
{
  regsub_t rs;
  const char *s;
  char *ss, *p;
  int r, l;

  if((r = regcomp(&rs.rx, pat, cflags)))
  {
    char buf[256];
    regerror(r, &rs.rx, buf, sizeof(buf));
    fprintf(stderr, "tcregsub: %s\n", buf);
    return NULL;
  }

  rs.m = calloc(rs.rx.re_nsub + 1, sizeof(*rs.m));
  l = strlen(str);
  ss = malloc(l + 1);
  p = ss;
  s = str;

  while(*s)
  {
    int ml;
    if(regexec(&rs.rx, s, rs.rx.re_nsub + 1, rs.m, 0))
      break;

    strncpy(p, s, rs.m[0].rm_so);
    p += rs.m[0].rm_so;
    ml = rs.m[0].rm_eo - rs.m[0].rm_so;
    if(ml > 0)
    {
      char *ms = malloc(ml + 1);
      char *rp;
      int sl, o;

      rs.s = s;
      rp = tcstrexp(sub, "{", "}", 0, rs_lookup, &rs,
                    TCSTREXP_KEEPUNDEF | TCSTREXP_FREE);
      sl = strlen(rp);
      o = p - ss;
      ss = realloc(ss, l += sl);
      p = ss + o;

      strcpy(p, rp);
      p += sl;
      free(rp);
      free(ms);
    }
    s += rs.m[0].rm_eo;
  }

  strcpy(p, s);
  free(rs.m);
  regfree(&rs.rx);
  return ss;
}

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