petidomo/libtext/find_string.c

/*
 * Copyright (c) 1995-2013 Peter Simons <simons@cryp.to>
 * Copyright (c) 2000-2001 Cable & Wireless GmbH
 * Copyright (c) 1999-2000 CyberSolutions GmbH
 *
 * 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 <string.h>
#include "text.h"

/* A simple text search.

   This function performs a simple, case-independent text search in
   the indicated buffer.

   RETURNS: FindString() returns a pointer to the first occurance of
   "string" in "buffer", or NULL, if the string was not found.

   NOTE: This routine will perform poorly on larger text buffers.

   AUTHOR: Peter Simons <simons@rhein.de>

 */

char *
text_find_string(char * buffer, /* text buffer */
           char * string        /* string to find */
)

{
    int         buffer_len;
    int         string_len;
    char *      result;

    /* Sanity checks. */

    assert(buffer != NULL);
    assert(string != NULL);
    if (!buffer || !string)
      return NULL;

    buffer_len = strlen(buffer);
    string_len = strlen(string);

    if (buffer_len == 0 || buffer_len < string_len)
      return NULL;
    if (string_len == 0)
      return buffer;

    /* Now look for the string. */

    for(result = NULL; buffer_len >= string_len; buffer++, buffer_len--) {
        if (!strncasecmp(buffer, string, string_len)) {
            result = buffer;
            break;
        }
    }
    return result;
}