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165 lines
4.8 KiB
C
165 lines
4.8 KiB
C
/*
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+----------------------------------------------------------------------+
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| PHP Version 5 |
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+----------------------------------------------------------------------+
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| Copyright (c) 1997-2006 The PHP Group |
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+----------------------------------------------------------------------+
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| This source file is subject to version 3.01 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_01.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_LENGTH 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(void *s1, int32_t l1, void *s2, int32_t l2, zend_uchar str_type, 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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int32_t i1, i2, j1, j2, cp1, cp2;
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int32_t c0, c1, c2;
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UChar32 ch1, ch2;
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if (str_type == IS_UNICODE) {
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cp1 = u_countChar32((UChar *)s1, l1);
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cp2 = u_countChar32((UChar *)s2, l2);
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if (cp1 == 0) return cp2*cost_ins;
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if (cp2 == 0) return cp1*cost_del;
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if ((cp1>LEVENSHTEIN_MAX_LENGTH)||(cp2>LEVENSHTEIN_MAX_LENGTH)) {
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return -1;
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}
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p1 = safe_emalloc((cp2+1), sizeof(int), 0);
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p2 = safe_emalloc((cp2+1), sizeof(int), 0);
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} else {
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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_LENGTH)||(l2>LEVENSHTEIN_MAX_LENGTH)) {
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return -1;
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}
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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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}
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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, j1 = 0 ; i1 < l1 ; i1++) {
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p2[0] = p1[0] + cost_del;
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if (str_type == IS_UNICODE) {
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U16_NEXT((UChar *)s1, j1, l1, ch1);
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}
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for (i2 = 0, j2 = 0 ; i2 < l2 ; i2++) {
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if (str_type == IS_UNICODE) {
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U16_NEXT((UChar *)s2, j2, l2, ch2);
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c0 = p1[i2] + ((ch1==ch2) ? 0 : cost_rep);
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} else {
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c0 = p1[i2] + ((*((char *)s1+i1)==*((char *)s2+i2)) ? 0 : cost_rep);
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}
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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(void *str1, void *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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int argc = ZEND_NUM_ARGS();
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void *str1, *str2;
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int32_t str1_len, str2_len;
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zend_uchar str1_type, str2_type;
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long cost_ins, cost_rep, cost_del;
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char *callback_name;
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int distance = -1;
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switch (argc) {
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case 2: /* just two string: use maximum performance version */
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if (zend_parse_parameters(2 TSRMLS_CC, "TT",
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&str1, &str1_len, &str1_type,
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&str2, &str2_len, &str2_type) == FAILURE) {
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return;
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}
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distance = reference_levdist(str1, str1_len, str2, str2_len, str1_type, 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_parse_parameters(5 TSRMLS_CC, "TTlll",
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&str1, &str1_len, &str1_type,
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&str2, &str2_len, &str2_type,
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&cost_ins, &cost_rep, &cost_del) == FAILURE) {
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return;
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}
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distance = reference_levdist(str1, str1_len, str2, str2_len, str1_type, cost_ins, cost_rep, 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_parse_parameters(3 TSRMLS_CC, "TTs",
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&str1, &str1_len, &str1_type,
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&str2, &str2_len, &str2_type,
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&callback_name) == FAILURE) {
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return;
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}
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distance = custom_levdist(str1, str2, 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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