/*
 * Copyright (c) 2004-2013 Sergey Lyubka <valenok@gmail.com>
 * Copyright (c) 2013 Cesanta Limited
 * All rights reserved
 *
 * This library is dual-licensed: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation. For the terms of this
 * license, see <http://www.gnu.org/licenses/>.
 *
 * You are free to use this library under the terms of the GNU General
 * Public License, 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.
 *
 * Alternatively, you can license this library under a commercial
 * license, as set out in <http://cesanta.com/products.html>.
 */

#ifndef SLRE_HEADER_DEFINED
#define SLRE_HEADER_DEFINED

/*
 * This is a regular expression library that implements a subset of Perl RE.
 * Please refer to http://cesanta.com/docs/slre for detailed reference.
 */

/* This structure describes a matched fragment, a "capture" */
struct slre_cap {
  const char *ptr;  /* Points to the matched fragment */
  int len;          /* Length of the matched fragment */
};

/*
 * Match string buffer "buf" of length "buf_len" against "regexp", which should
 * conform the syntax outlined below. If regular expression
 * "regexp" contains brackets, slre_match() will capture the respective
 * substring. Array of captures, "caps", must have at least as many elements
 * as number of opening parenthesis in the regexp.
 *
 * Return:
 *   0, if there is no match. error_msg will contain the error message
 *   >0, number of bytes matched in a buffer
 */
int slre_match(const char *regexp, const char *buf, int buf_len,
               struct slre_cap *caps, const char **error_msg);

/*
 * Supported syntax:
 *    ^        Match beginning of a buffer
 *    $        Match end of a buffer
 *    ()       Grouping and substring capturing
 *    [...]    Match any character from set
 *    [^...]   Match any character but ones from set
 *    \s       Match whitespace
 *    \S       Match non-whitespace
 *    \d       Match decimal digit
 *    \r       Match carriage return
 *    \n       Match newline
 *    +        Match one or more times (greedy)
 *    +?       Match one or more times (non-greedy)
 *    *        Match zero or more times (greedy)
 *    *?       Match zero or more times (non-greedy)
 *    ?        Match zero or once
 *    \xDD     Match byte with hex value 0xDD
 *    \meta    Match one of the meta character: ^$().[*+\?
 *    x|y      Match x or y (alternation operator)

 * Usage example: parsing HTTP request line.
 *
 *  const char *request = "GET /index.html HTTP/1.0\r\n\r\n";
 *  struct slre_capture method, uri, version_min, version_maj;
 *
 *  error = slre_match("^\\s*(GET|POST)\\s+(\\S+)\\s+HTTP/(\\d)\\.(\\d)",
 *                     request, strlen(request),
 *                     &method, &uri, &version_min, &version_maj);
 *
 *  if (error != NULL) {
 *    printf("Error parsing HTTP request: %s\n", error);
 *  } else {
 *    printf("Requested URI: [%.*s]\n", uri.len, uri.ptr);
 *  }
 */

#endif