libast/comp/regexp.c

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1985-2011 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                 Eclipse Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*          http://www.eclipse.org/org/documents/epl-v10.html           *
*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                 Glenn Fowler <gsf@research.att.com>                  *
*                  David Korn <dgk@research.att.com>                   *
*                   Phong Vo <kpv@research.att.com>                    *
*                                                                      *
***********************************************************************/
#pragma prototyped
/*
 * <regexp.h> library support
 */

#define _REGEXP_DECLARE

#include <ast.h>
#include <regexp.h>
#include <regex.h>
#include <align.h>

typedef struct
{
    regex_t     re;
    char*       buf;
    char*       cur;
    unsigned int    size;
} Env_t;

static void*
block(void* handle, void* data, size_t size)
{
    register Env_t* env = (Env_t*)handle;

    if (data || (size = roundof(size, ALIGN_BOUND2)) > (env->buf + env->size - env->cur))
        return 0;
    data = (void*)env->cur;
    env->cur += size;
    return data;
}

int
_re_comp(regexp_t* re, const char* pattern, char* handle, unsigned int size)
{
    register Env_t* env = (Env_t*)handle;
    register int    n;

    if (size <= sizeof(Env_t))
        return 50;
    env->buf = env->cur = (char*)env + sizeof(Env_t);
    env->size = size - sizeof(Env_t);
    regalloc(env, block, REG_NOFREE);
    n = regcomp(&env->re, pattern, REG_LENIENT|REG_NULL);
    switch (n)
    {
    case 0:
        break;
    case REG_ERANGE:
        n = 11;
        break;
    case REG_BADBR:
        n = 16;
        break;
    case REG_ESUBREG:
        n = 25;
        break;
    case REG_EPAREN:
        n = 42;
        break;
    case REG_EBRACK:
        n = 49;
        break;
    default:
        n = 50;
        break;
    }
    re->re_nbra = env->re.re_nsub;
    return n;
}

int
_re_exec(regexp_t* re, const char* subject, const char* handle, int anchor)
{
    register Env_t* env = (Env_t*)handle;
    register int    n;
    regmatch_t  match[elementsof(re->re_braslist)+1];

    if (regexec(&env->re, subject, elementsof(match), match, 0) || anchor && match[0].rm_so)
        return 0;
    re->re_loc1 = (char*)subject + match[0].rm_so;
    re->re_loc2 = (char*)subject + match[0].rm_eo;
    for (n = 1; n <= env->re.re_nsub; n++)
    {
        re->re_braslist[n-1] = (char*)subject + match[n].rm_so;
        re->re_braelist[n-1] = (char*)subject + match[n].rm_eo;
    }
    return 1;
}

char*
_re_putc(int c)
{
    static Sfio_t*  sp;

    if (!sp && !(sp = sfstropen()))
        return 0;
    if (!c)
        return sfstruse(sp);
    sfputc(sp, c);
    return 0;
}