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https://github.com/php/php-src.git
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151 lines
4.2 KiB
C
151 lines
4.2 KiB
C
/*
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+----------------------------------------------------------------------+
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| PHP Version 5 |
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+----------------------------------------------------------------------+
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| Copyright (c) 1997-2004 The PHP Group |
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+----------------------------------------------------------------------+
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| This source file is subject to version 3.0 of the PHP license, |
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| that is bundled with this package in the file LICENSE, and is |
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| available through the world-wide-web at the following url: |
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| http://www.php.net/license/3_0.txt. |
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| If you did not receive a copy of the PHP license and are unable to |
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| obtain it through the world-wide-web, please send a note to |
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| license@php.net so we can mail you a copy immediately. |
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+----------------------------------------------------------------------+
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| Author: Hartmut Holzgraefe <hholzgra@php.net> |
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+----------------------------------------------------------------------+
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*/
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/* $Id$ */
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#include "php.h"
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#include <stdlib.h>
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#include <errno.h>
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#include <ctype.h>
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#include "php_string.h"
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#define LEVENSHTEIN_MAX_LENTH 255
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/* {{{ reference_levdist
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* reference implementation, only optimized for memory usage, not speed */
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static int reference_levdist(const char *s1, int l1,
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const char *s2, int l2,
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int cost_ins, int cost_rep, int cost_del )
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{
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int *p1, *p2, *tmp;
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int i1, i2, c0, c1, c2;
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if(l1==0) return l2*cost_ins;
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if(l2==0) return l1*cost_del;
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if((l1>LEVENSHTEIN_MAX_LENTH)||(l2>LEVENSHTEIN_MAX_LENTH))
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return -1;
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p1 = safe_emalloc((l2+1), sizeof(int), 0);
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p2 = safe_emalloc((l2+1), sizeof(int), 0);
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for(i2=0;i2<=l2;i2++)
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p1[i2] = i2*cost_ins;
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for(i1=0;i1<l1;i1++)
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{
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p2[0]=p1[0]+cost_del;
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for(i2=0;i2<l2;i2++)
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{
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c0=p1[i2]+((s1[i1]==s2[i2])?0:cost_rep);
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c1=p1[i2+1]+cost_del; if(c1<c0) c0=c1;
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c2=p2[i2]+cost_ins; if(c2<c0) c0=c2;
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p2[i2+1]=c0;
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}
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tmp=p1; p1=p2; p2=tmp;
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}
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c0=p1[l2];
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efree(p1);
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efree(p2);
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return c0;
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}
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/* }}} */
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/* {{{ custom_levdist
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*/
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static int custom_levdist(char *str1, char *str2, char *callback_name TSRMLS_DC)
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{
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php_error_docref(NULL TSRMLS_CC, E_WARNING, "The general Levenshtein support is not there yet");
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/* not there yet */
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return -1;
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}
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/* }}} */
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/* {{{ proto int levenshtein(string str1, string str2)
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Calculate Levenshtein distance between two strings */
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PHP_FUNCTION(levenshtein)
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{
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zval **str1, **str2, **cost_ins, **cost_rep, **cost_del, **callback_name;
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int distance=-1;
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switch(ZEND_NUM_ARGS()) {
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case 2: /* just two string: use maximum performance version */
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if (zend_get_parameters_ex(2, &str1, &str2) == FAILURE) {
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WRONG_PARAM_COUNT;
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}
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convert_to_string_ex(str1);
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convert_to_string_ex(str2);
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distance = reference_levdist(Z_STRVAL_PP(str1), Z_STRLEN_PP(str1),
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Z_STRVAL_PP(str2), Z_STRLEN_PP(str2), 1, 1, 1);
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break;
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case 5: /* more general version: calc cost by ins/rep/del weights */
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if (zend_get_parameters_ex(5, &str1, &str2, &cost_ins, &cost_rep, &cost_del) == FAILURE) {
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WRONG_PARAM_COUNT;
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}
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convert_to_string_ex(str1);
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convert_to_string_ex(str2);
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convert_to_long_ex(cost_ins);
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convert_to_long_ex(cost_rep);
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convert_to_long_ex(cost_del);
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distance = reference_levdist(Z_STRVAL_PP(str1), Z_STRLEN_PP(str1),
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Z_STRVAL_PP(str2), Z_STRLEN_PP(str2),
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Z_LVAL_PP(cost_ins), Z_LVAL_PP(cost_rep),
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Z_LVAL_PP(cost_del));
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break;
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case 3: /* most general version: calc cost by user-supplied function */
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if (zend_get_parameters_ex(3, &str1, &str2, &callback_name) == FAILURE) {
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WRONG_PARAM_COUNT;
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}
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convert_to_string_ex(str1);
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convert_to_string_ex(str2);
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convert_to_string_ex(callback_name);
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distance = custom_levdist(Z_STRVAL_PP(str1), Z_STRVAL_PP(str2),
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Z_STRVAL_PP(callback_name) TSRMLS_CC);
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break;
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default:
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WRONG_PARAM_COUNT;
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}
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if(distance<0) {
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php_error_docref(NULL TSRMLS_CC, E_WARNING, "Argument string(s) too long");
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}
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RETURN_LONG(distance);
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}
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/* }}} */
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/*
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* Local variables:
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* tab-width: 4
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* c-basic-offset: 4
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* End:
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* vim600: sw=4 ts=4 fdm=marker
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* vim<600: sw=4 ts=4
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*/
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