More updates towards 2.0.

[mpdm.git] / mpdm_r.c

/*

    MPDM - Minimum Profit Data Manager
    Copyright (C) 2003/2010 Angel Ortega <angel@triptico.com>

    mpdm_r.c - Regular expressions

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; either version 2
    of the License, or (at your option) any later version.

    This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

    http://www.triptico.com

*/

#include "config.h"

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

#include "mpdm.h"

#ifdef CONFOPT_PCRE
#include <pcreposix.h>
#endif

#ifdef CONFOPT_SYSTEM_REGEX
#include <regex.h>
#endif

#ifdef CONFOPT_INCLUDED_REGEX
#include "gnu_regex.h"
#endif


/** data **/

/* matching of the last regex */

int mpdm_regex_offset = -1;
int mpdm_regex_size = 0;

/* number of substitutions in last sregex */

int mpdm_sregex_count = 0;


/** code **/

static wchar_t *regex_flags(const mpdm_t r)
{
        return wcsrchr((wchar_t *) r->data, *(wchar_t *) r->data);
}


static mpdm_t mpdm_regcomp(mpdm_t r)
{
        mpdm_t c = NULL;
        mpdm_t regex_cache = NULL;

        /* if cache does not exist, create it */
        if ((regex_cache = mpdm_hget_s(mpdm_root(), L"__REGEX_CACHE__")) == NULL) {
                regex_cache = MPDM_H(0);
                mpdm_hset_s(mpdm_root(), L"__REGEX_CACHE__", regex_cache);
        }

        /* search the regex in the cache */
        if ((c = mpdm_hget(regex_cache, r)) == NULL) {
                mpdm_t rmb;
                regex_t re;
                char *regex;
                char *flags;
                int f = REG_EXTENDED;

                /* not found; regex must be compiled */

                /* convert to mbs */
                rmb = MPDM_2MBS(r->data);

                regex = (char *) rmb->data;
                if ((flags = strrchr(regex, *regex)) == NULL)
                        return NULL;

                if (strchr(flags, 'i') != NULL)
                        f |= REG_ICASE;
                if (strchr(flags, 'm') != NULL)
                        f |= REG_NEWLINE;

                regex++;
                *flags = '\0';

                if (!regcomp(&re, regex, f)) {
                        void *ptr;

                        if ((ptr = malloc(sizeof(regex_t))) != NULL) {
                                /* copies */
                                memcpy(ptr, &re, sizeof(regex_t));

                                /* create value */
                                c = mpdm_new(MPDM_FREE, ptr, sizeof(regex_t));

                                /* stores */
                                mpdm_hset(regex_cache, r, c);
                        }
                }
        }

        return c;
}


static mpdm_t regex1(mpdm_t r, const mpdm_t v, int offset)
/* test for one regex */
{
        mpdm_t w = NULL;
        mpdm_t cr;

        /* no matching yet */
        mpdm_regex_offset = -1;

        /* compile the regex */
        if ((cr = mpdm_regcomp(r)) != NULL) {
                regmatch_t rm;
                char *ptr;
                wchar_t *last;
                int o = 0;
                int f = 0;

                /* takes pointer to 'last' flag */
                if ((last = regex_flags(r)) != NULL)
                        last = wcschr(last, 'l');

                /* convert to mbs */
                ptr = mpdm_wcstombs((wchar_t *) v->data + offset, NULL);

                /* match? */
                while (regexec((regex_t *) cr->data, ptr + o, 1,
                               &rm, offset > 0 ? REG_NOTBOL : 0) == 0) {
                        f++;

                        /* if 'last' is not set, it's done */
                        if (last == NULL)
                                break;

                        rm.rm_so += o;
                        rm.rm_eo += o;
                        o = rm.rm_eo;
                }

                if (f) {
                        /* converts to mbs the string from the beginning
                           to the start of the match, just to know
                           the size (and immediately frees it) */
                        free(mpdm_mbstowcs(ptr, &mpdm_regex_offset, rm.rm_so));

                        /* add the offset */
                        mpdm_regex_offset += offset;

                        /* create now the matching string */
                        w = MPDM_NMBS(ptr + rm.rm_so, rm.rm_eo - rm.rm_so);

                        /* and store the size */
                        mpdm_regex_size = mpdm_size(w);
                }

                free(ptr);
        }

        return w;
}


/**
 * mpdm_regex - Matches a regular expression.
 * @r: the regular expression
 * @v: the value to be matched
 * @offset: offset from the start of v->data
 *
 * Matches a regular expression against a value. Valid flags are 'i',
 * for case-insensitive matching, 'm', to treat the string as a
 * multiline string (i.e., one containing newline characters), so
 * that ^ and $ match the boundaries of each line instead of the
 * whole string, 'l', to return the last matching instead of the
 * first one, or 'g', to match globally; in that last case, an array
 * containing all matches is returned instead of a string scalar.
 *
 * If @r is a string, an ordinary regular expression matching is tried
 * over the @v string. If the matching is possible, the match result
 * is returned, or NULL otherwise.
 *
 * If @r is an array (of strings), each element is tried sequentially
 * as an individual regular expression over the @v string, each one using
 * the offset returned by the previous match. All regular expressions
 * must match to be successful. If this is the case, an array (with
 * the same number of arguments) is returned containing the matched
 * strings, or NULL otherwise.
 *
 * If @r is NULL, the result of the previous regex matching
 * is returned as a two element array. The first element will contain
 * the character offset of the matching and the second the number of
 * characters matched. If the previous regex was unsuccessful, NULL
 * is returned.
 * [Regular Expressions]
 */
mpdm_t mpdm_regex(mpdm_t r, const mpdm_t v, int offset)
{
        mpdm_t w = NULL;

        /* special case: if r is NULL, return previous match */
        if (r == NULL) {
                /* if previous regex was successful... */
                if (mpdm_regex_offset != -1) {
                        w = MPDM_A(2);

                        mpdm_aset(w, MPDM_I(mpdm_regex_offset), 0);
                        mpdm_aset(w, MPDM_I(mpdm_regex_size), 1);
                }

                return w;
        }

        /* if the string to be tested is NULL, return NULL */
        if (v == NULL)
                return NULL;

        if (r->flags & MPDM_MULTIPLE) {
                int n;
                mpdm_t t;

                /* multiple value; try sequentially all regexes,
                   moving the offset forward */

                w = MPDM_A(mpdm_size(r));

                for (n = 0; n < mpdm_size(r); n++) {
                        t = mpdm_regex(mpdm_aget(r, n), v, offset);

                        /* if not found, invalid all search and exit */
                        if (t == NULL) {
                                w = NULL;
                                break;
                        }

                        /* found; store and move forward */
                        mpdm_aset(w, t, n);
                        offset = mpdm_regex_offset + mpdm_regex_size;
                }
        }
        else {
                wchar_t *global;

                /* takes pointer to 'global' flag */
                if ((global = regex_flags(r)) != NULL)
                        global = wcschr(global, 'g');

                if (global != NULL) {
                        mpdm_t t;

                        /* match sequentially until done */
                        w = MPDM_A(0);

                        while ((t = regex1(r, v, offset)) != NULL) {
                                mpdm_push(w, t);

                                offset = mpdm_regex_offset + mpdm_regex_size;
                        }

                        /* no matches? convert to NULL */
                        if (mpdm_size(w) == 0)
                                w = NULL;
                }
                else
                        w = regex1(r, v, offset);
        }

        return w;
}


static mpdm_t expand_ampersands(const mpdm_t s, const mpdm_t t)
/* substitutes all unescaped ampersands in s with t */
{
        const wchar_t *sptr = mpdm_string(s);
        wchar_t *wptr;
        mpdm_t r = NULL;

        if (s == NULL)
                return s;

        while ((wptr = wcschr(sptr, L'\\')) != NULL ||
                (wptr = wcschr(sptr, L'&')) != NULL) {
                int n = wptr - sptr;

                /* add the leading part */
                r = mpdm_strcat_sn(r, sptr, n);

                if (*wptr == L'\\') {
                        if (*(wptr + 1) == L'&' || *(wptr + 1) == L'\\')
                                wptr++;

                        r = mpdm_strcat_sn(r, wptr, 1);
                }
                else
                if (*wptr == '&')
                        r = mpdm_strcat(r, t);

                sptr = wptr + 1;
        }

        if (r == NULL)
                r = s;
        else {
                /* add the rest of the string */
                r = mpdm_strcat_s(r, sptr);
        }

        return r;
}


/**
 * mpdm_sregex - Matches and substitutes a regular expression.
 * @r: the regular expression
 * @v: the value to be matched
 * @s: the substitution string, hash or code
 * @offset: offset from the start of v->data
 *
 * Matches a regular expression against a value, and substitutes the
 * found substring with @s. Valid flags are 'i', for case-insensitive
 * matching, and 'g', for global replacements (all ocurrences in @v
 * will be replaced, instead of just the first found one).
 *
 * If @s is executable, it's executed with the matched part as
 * the only argument and its return value is used as the
 * substitution string.
 *
 * If @s is a hash, the matched string is used as a key to it and
 * its value used as the substitution. If this value itself is
 * executable, it's executed with the matched string as its only
 * argument and its return value used as the substitution.
 *
 * If @r is NULL, returns the number of substitutions made in the
 * previous call to mpdm_sregex() (can be zero if none was done).
 *
 * The global variables @mpdm_regex_offset and @mpdm_regex_size are
 * set to the offset of the matched string and the size of the
 * replaced string, respectively.
 *
 * Returns the modified string, or the original one if no substitutions
 * were done.
 * [Regular Expressions]
 */
mpdm_t mpdm_sregex(mpdm_t r, const mpdm_t v, const mpdm_t s, int offset)
{
        mpdm_t cr;
        mpdm_t o = v;

        if (r == NULL) {
                /* return last count */
                return MPDM_I(mpdm_sregex_count);
        }

        if (v == NULL)
                return NULL;

        /* compile the regex */
        if ((cr = mpdm_regcomp(r)) != NULL) {
                char *ptr;
                int f, i = 0;
                wchar_t *global;
                mpdm_t t;

                /* takes pointer to global flag */
                if ((global = regex_flags(r)) !=NULL)
                        global = wcschr(global, 'g');

                /* store the first part */
                o = MPDM_NS(v->data, offset);

                /* convert to mbs */
                if ((ptr = mpdm_wcstombs((wchar_t *) v->data + offset, NULL)) == NULL)
                        return NULL;

                /* reset count */
                mpdm_sregex_count = 0;
                mpdm_regex_offset = -1;

                do {
                        regmatch_t rm;

                        /* try match */
                        f = !regexec((regex_t *) cr->data, ptr + i,
                                     1, &rm, offset > 0 ? REG_NOTBOL : 0);

                        if (f) {
                                /* creates a string from the beginning
                                   to the start of the match */
                                t = MPDM_NMBS(ptr + i, rm.rm_so);
                                o = mpdm_strcat(o, t);

                                /* store offset of substitution */
                                mpdm_regex_offset = mpdm_size(t) + offset;

                                /* get the matched part */
                                t = MPDM_NMBS(ptr + i + rm.rm_so, rm.rm_eo - rm.rm_so);

                                /* is s an executable value? */
                                if (MPDM_IS_EXEC(s)) {
                                        /* protect o from sweeping */
                                        mpdm_ref(o);

                                        /* execute s, with t as argument */
                                        t = mpdm_exec_1(s, t);

                                        mpdm_unref(o);
                                }
                                else
                                        /* is s a hash? use match as key */
                                if (MPDM_IS_HASH(s)) {
                                        mpdm_t v = mpdm_hget(s, t);

                                        /* is the value executable? */
                                        if (MPDM_IS_EXEC(v))
                                                v = mpdm_exec_1(v, t);

                                        t = v;
                                }
                                else
                                        t = expand_ampersands(s, t);

                                /* appends the substitution string */
                                o = mpdm_strcat(o, t);

                                /* store size of substitution */
                                mpdm_regex_size = mpdm_size(t);

                                i += rm.rm_eo;

                                /* one more substitution */
                                mpdm_sregex_count++;
                        }

                } while (f && global);

                /* no (more) matches; convert and append the rest */
                t = MPDM_MBS(ptr + i);
                o = mpdm_strcat(o, t);

                free(ptr);
        }

        return o;
}