text: /*
     +----------------------------------------------------------------------+
     | PHP Version 7                                                        |
     +----------------------------------------------------------------------+
     | Copyright (c) The PHP Group                                          |
     +----------------------------------------------------------------------+
     | This source file is subject to version 3.01 of the PHP license,      |
     | that is bundled with this package in the file LICENSE, and is        |
     | available through the world-wide-web at the following url:           |
     | http://www.php.net/license/3_01.txt                                  |
     | If you did not receive a copy of the PHP license and are unable to   |
     | obtain it through the world-wide-web, please send a note to          |
     | license@php.net so we can mail you a copy immediately.               |
     +----------------------------------------------------------------------+
     | Author: Hartmut Holzgraefe <hholzgra@php.net>                        |
     +----------------------------------------------------------------------+
   */
  
  #include "php.h"
  #include <stdlib.h>
  #include <errno.h>
  #include <ctype.h>
  #include "php_string.h"
  
  #define LEVENSHTEIN_MAX_LENGTH 255
  
  /* {{{ reference_levdist
   * reference implementation, only optimized for memory usage, not speed */
  static zend_long reference_levdist(const char *s1, size_t l1, const char *s2, size_t l2, zend_long cost_ins, zend_long cost_rep, zend_long cost_del )
  {
  	zend_long *p1, *p2, *tmp;
  	zend_long c0, c1, c2;
  	size_t i1, i2;
  
  	if (l1 == 0) {
  		return l2 * cost_ins;
  	}
  	if (l2 == 0) {
  		return l1 * cost_del;
  	}
  
  	if ((l1 > LEVENSHTEIN_MAX_LENGTH) || (l2 > LEVENSHTEIN_MAX_LENGTH)) {
  		return -1;
  	}
  	p1 = safe_emalloc((l2 + 1), sizeof(zend_long), 0);
  	p2 = safe_emalloc((l2 + 1), sizeof(zend_long), 0);
  
  	for (i2 = 0; i2 <= l2; i2++) {
  		p1[i2] = i2 * cost_ins;
  	}
  	for (i1 = 0; i1 < l1 ; i1++) {
  		p2[0] = p1[0] + cost_del;
  
  		for (i2 = 0; i2 < l2; i2++) {
  			c0 = p1[i2] + ((s1[i1] == s2[i2]) ? 0 : cost_rep);
  			c1 = p1[i2 + 1] + cost_del;
  			if (c1 < c0) {
  				c0 = c1;
  			}
  			c2 = p2[i2] + cost_ins;
  			if (c2 < c0) {
  				c0 = c2;
  			}
  			p2[i2 + 1] = c0;
  		}
  		tmp = p1;
  		p1 = p2;
  		p2 = tmp;
  	}
  	c0 = p1[l2];
  
  	efree(p1);
  	efree(p2);
  
  	return c0;
  }
  /* }}} */
  
  /* {{{ custom_levdist
   */
  static int custom_levdist(char *str1, char *str2, char *callback_name)
  {
  	php_error_docref(NULL, E_WARNING, "The general Levenshtein support is not there yet");
  	/* not there yet */
  
  	return -1;
  }
  /* }}} */
  
  /* {{{ proto int levenshtein(string str1, string str2[, int cost_ins, int cost_rep, int cost_del])
     Calculate Levenshtein distance between two strings */
  PHP_FUNCTION(levenshtein)
  {
  	int argc = ZEND_NUM_ARGS();
  	char *str1, *str2;
  	char *callback_name;
  	size_t str1_len, str2_len, callback_len;
  	zend_long cost_ins, cost_rep, cost_del;
  	zend_long distance = -1;
  
  	switch (argc) {
  		case 2: /* just two strings: use maximum performance version */
  			if (zend_parse_parameters(2, "ss", &str1, &str1_len, &str2, &str2_len) == FAILURE) {
  				return;
  			}
  			distance = reference_levdist(str1, str1_len, str2, str2_len, 1, 1, 1);
  			break;
  
  		case 5: /* more general version: calc cost by ins/rep/del weights */
  			if (zend_parse_parameters(5, "sslll", &str1, &str1_len, &str2, &str2_len, &cost_ins, &cost_rep, &cost_del) == FAILURE) {
  				return;
  			}
  			distance = reference_levdist(str1, str1_len, str2, str2_len, cost_ins, cost_rep, cost_del);
  			break;
  
  		case 3: /* most general version: calc cost by user-supplied function */
  			if (zend_parse_parameters(3, "sss", &str1, &str1_len, &str2, &str2_len, &callback_name, &callback_len) == FAILURE) {
  				return;
  			}
  			distance = custom_levdist(str1, str2, callback_name);
  			break;
  
  		default:
  			WRONG_PARAM_COUNT;
  	}
  
  	if (distance < 0 && /* TODO */ ZEND_NUM_ARGS() != 3) {
  		php_error_docref(NULL, E_WARNING, "Argument string(s) too long");
  	}
  
  	RETURN_LONG(distance);
  }
  /* }}} */
  
  /*
   * Local variables:
   * tab-width: 4
   * c-basic-offset: 4
   * End:
   * vim600: sw=4 ts=4 fdm=marker
   * vim<600: sw=4 ts=4
   */
  