source: vendor/current/lib/util/substitute.c

/* 
   Unix SMB/CIFS implementation.
   Samba utility functions
   
   Copyright (C) Andrew Tridgell 1992-2001
   Copyright (C) Simo Sorce      2001-2002
   Copyright (C) Martin Pool     2003
   Copyright (C) James Peach     2005
   
   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "replace.h"
#include "debug.h"
#ifndef SAMBA_UTIL_CORE_ONLY
#include "charset/charset.h"
#else
#include "charset_compat.h"
#endif
#include "substitute.h"

/**
 * @file
 * @brief Substitute utilities.
 **/

/**
 Substitute a string for a pattern in another string. Make sure there is
 enough room!

 This routine looks for pattern in s and replaces it with
 insert. It may do multiple replacements or just one.

 Any of " ; ' $ or ` in the insert string are replaced with _
 if len==0 then the string cannot be extended. This is different from the old
 use of len==0 which was for no length checks to be done.
**/

static void string_sub2(char *s,const char *pattern, const char *insert, size_t len,
                        bool remove_unsafe_characters, bool replace_once,
                        bool allow_trailing_dollar)
{
        char *p;
        ssize_t ls, lp, li, i;

        if (!insert || !pattern || !*pattern || !s)
                return;

        ls = (ssize_t)strlen(s);
        lp = (ssize_t)strlen(pattern);
        li = (ssize_t)strlen(insert);

        if (len == 0)
                len = ls + 1; /* len is number of *bytes* */

        while (lp <= ls && (p = strstr_m(s,pattern))) {
                if (ls + (li-lp) >= len) {
                        DEBUG(0,("ERROR: string overflow by "
                                "%d in string_sub(%.50s, %d)\n",
                                 (int)(ls + (li-lp) - len),
                                 pattern, (int)len));
                        break;
                }
                if (li != lp) {
                        memmove(p+li,p+lp,strlen(p+lp)+1);
                }
                for (i=0;i<li;i++) {
                        switch (insert[i]) {
                        case '$':
                                /* allow a trailing $
                                 * (as in machine accounts) */
                                if (allow_trailing_dollar && (i == li - 1 )) {
                                        p[i] = insert[i];
                                        break;
                                }
                        case '`':
                        case '"':
                        case '\'':
                        case ';':
                        case '%':
                        case '\r':
                        case '\n':
                                if ( remove_unsafe_characters ) {
                                        p[i] = '_';
                                        /* yes this break should be here
                                         * since we want to fall throw if
                                         * not replacing unsafe chars */
                                        break;
                                }
                        default:
                                p[i] = insert[i];
                        }
                }
                s = p + li;
                ls += (li-lp);

                if (replace_once)
                        break;
        }
}

void string_sub_once(char *s, const char *pattern,
                const char *insert, size_t len)
{
        string_sub2( s, pattern, insert, len, true, true, false );
}

void string_sub(char *s,const char *pattern, const char *insert, size_t len)
{
        string_sub2( s, pattern, insert, len, true, false, false );
}

/**
 * Talloc'ed version of string_sub
 */
_PUBLIC_ char *string_sub_talloc(TALLOC_CTX *mem_ctx, const char *s, 
                                const char *pattern, const char *insert)
{
        const char *p;
        char *ret;
        size_t len, alloc_len;

        if (insert == NULL || pattern == NULL || !*pattern || s == NULL)
                return NULL;

        /* determine length needed */
        len = strlen(s);
        
        for (p = strstr(s, pattern); p != NULL; 
             p = strstr(p+strlen(pattern), pattern)) {
                len += strlen(insert) - strlen(pattern);
        }

        alloc_len = MAX(len, strlen(s))+1;
        ret = talloc_array(mem_ctx, char, alloc_len);
        if (ret == NULL)
                return NULL;
        strncpy(ret, s, alloc_len);
        string_sub(ret, pattern, insert, alloc_len);

        ret = talloc_realloc(mem_ctx, ret, char, len+1);
        if (ret == NULL)
                return NULL;

        if (ret[len] != '\0') {
                DEBUG(0,("Internal error at %s(%d): string not terminated\n",
                         __FILE__, __LINE__));
                abort();
        }

        talloc_set_name_const(ret, ret);

        return ret;
}

/**
 Similar to string_sub() but allows for any character to be substituted. 
 Use with caution!
 if len==0 then the string cannot be extended. This is different from the old
 use of len==0 which was for no length checks to be done.
**/

_PUBLIC_ void all_string_sub(char *s,const char *pattern,const char *insert, size_t len)
{
        char *p;
        ssize_t ls,lp,li;

        if (!insert || !pattern || !s)
                return;

        ls = (ssize_t)strlen(s);
        lp = (ssize_t)strlen(pattern);
        li = (ssize_t)strlen(insert);

        if (!*pattern)
                return;

        if (len == 0)
                len = ls + 1; /* len is number of *bytes* */

        while (lp <= ls && (p = strstr_m(s,pattern))) {
                if (ls + (li-lp) >= len) {
                        DEBUG(0,("ERROR: string overflow by "
                                "%d in all_string_sub(%.50s, %d)\n",
                                 (int)(ls + (li-lp) - len),
                                 pattern, (int)len));
                        break;
                }
                if (li != lp) {
                        memmove(p+li,p+lp,strlen(p+lp)+1);
                }
                memcpy(p, insert, li);
                s = p + li;
                ls += (li-lp);
        }
}