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# fallback to unoptimized version for 4.0.4 release
This commit is contained in:
Hartmut Holzgraefe
parent
be895bcb96
commit
63e6b0b5bf
2 changed files with 94 additions and 152 deletions
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@ -23,162 +23,47 @@
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#include <ctype.h>
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#include "php_string.h"
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/* faster, but obfuscated, all operations have a cost of 1 */
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static int fastest_levdist(const char *s1, const char *s2)
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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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register char *p1,*p2;
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register int i,j,n;
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int l1=0,l2=0;
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char r[512];
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const char *tmp;
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/* skip equal start sequence, if any */
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while(*s1==*s2) {
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if(!*s1) break;
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s1++; s2++;
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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 we already used up one string, then
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the result is the length of the other */
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if(*s1=='\0') return strlen(s2);
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if(*s2=='\0') return strlen(s1);
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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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/* length count */
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while(*s1++) l1++;
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while(*s2++) l2++;
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/* cut of equal tail sequence, if any */
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while(*--s1 == *--s2) {
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l1--; l2--;
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}
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p1=malloc(l2*sizeof(int));
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p2=malloc(l2*sizeof(int));
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/* reset pointers, adjust length */
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s1-=l1++;
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s2-=l2++;
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p1[0]=(s1[0]==s2[0])?0:cost_rep;
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/* possible dist to great? */
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if(abs(l1-l2)>=255) return -1;
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for(i2=1;i2<l2;i2++)
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p1[i2]=i2*cost_ins;
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/* swap if l2 longer than l1 */
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if(l1<l2) {
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tmp=s1; s1=s2; s2=tmp;
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l1 ^= l2; l2 ^= l1; l1 ^= l2;
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}
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for(i1=1;i1<l1;i1++)
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{
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p2[0]=i1*cost_del;
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for(i2=1;i2<l2;i2++)
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{
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c0=p1[i2-1]+((s1[i1]==s2[i2])?0:cost_rep);
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c1=p1[i2]+cost_del; if(c1<c0) c0=c1;
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c2=p2[i2-1]+cost_ins; if(c2<c0) c0=c2;
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p2[i2]=c0;
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}
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tmp=p1; p1=p2; p2=tmp;
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}
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/* fill initial row */
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n=1;
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for(i=0,p1=r;i<l1;i++,*p1++=n++,p1++) {/*empty*/}
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/* calc. rowwise */
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for(j=1;j<l2;j++) {
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/* init pointers and col#0 */
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p1 = r + !(j&1);
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p2 = r + (j&1);
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n=*p1+1;
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*p2++=n;p2++;
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s2++;
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/* foreach column */
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for(i=1;i<l1;i++) {
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if(*p1<n) n=*p1+(*(s1+i)!=*(s2)); /* replace cheaper than delete? */
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p1++;
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if(*++p1<n) n=*p1+1; /* insert cheaper then replace ? */
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*p2++=n++; /* update field and cost for next col's delete */
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p2++;
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}
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}
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c0=p1[l2-1];
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/* return result */
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return n-1;
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free(p1);
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free(p2);
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return c0;
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}
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static int weighted_levdist( const char *s1
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, const char *s2
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, const int cost_ins
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, const int cost_rep
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, const int cost_del
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)
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{
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register int *p1,*p2;
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register int i,j,n,c;
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int l1=0,l2=0;
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int r[512];
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const char *tmp;
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/* skip equal start sequence, if any */
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while(*s1==*s2) {
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if(!*s1) break;
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s1++; s2++;
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}
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/* if we already used up one string, then
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the result is the length of the other */
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if(*s1=='\0') return strlen(s2);
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if(*s2=='\0') return strlen(s1);
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/* length count */
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while(*s1++) l1++;
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while(*s2++) l2++;
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/* cut of equal tail sequence, if any */
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while(*--s1 == *--s2) {
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l1--; l2--;
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}
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/* reset pointers, adjust length */
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s1-=l1++;
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s2-=l2++;
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/* possible dist to great? */
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if(abs(l1-l2)>=255) return -1;
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/* swap if l2 longer than l1 */
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if(l1<l2) {
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tmp=s1; s1=s2; s2=tmp;
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l1 ^= l2; l2 ^= l1; l1 ^= l2;
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}
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if((l1==1)&&(l2==1)) {
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n= cost_del+cost_ins;
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return n<cost_rep?n:cost_rep;
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}
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/* fill initial row */
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n=cost_ins;
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for(i=0,p1=r;i<l1;i++,*p1++=n,p1++) {n+=cost_ins;}
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/* calc. rowwise */
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for(j=1;j<l2;j++) {
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/* init pointers and col#0 */
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p1 = r + !(j&1);
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p2 = r + (j&1);
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n=*p1+cost_del;
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*p2++=n;p2++;
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s2++;
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/* foreach column */
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for(i=1;i<l1;i++) {
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c = *p1; if(*(s1+i)!=*(s2)) c+=cost_rep;
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if(c<n) n=c; /* replace cheaper than delete? */
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p1++;
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c= *++p1+cost_ins;
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if(c<n) n=c; /* insert cheaper then replace ? */
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*p2++=n; /* update field and cost for next col's delete */
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n+=cost_del; /* update field and cost for next col's delete */
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p2++;
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}
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}
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/* return result */
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return n-=cost_del;
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}
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static int custom_levdist(char *str1,char *str2,char *callback_name)
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{
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php_error(E_WARNING,"the general Levenshtein support is not there yet");
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@ -202,8 +87,11 @@ PHP_FUNCTION(levenshtein)
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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 = fastest_levdist((*str1)->value.str.val, (*str2)->value.str.val);
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distance = reference_levdist((*str1)->value.str.val,(*str1)->value.str.len,
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(*str2)->value.str.val,(*str2)->value.str.len,
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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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@ -216,11 +104,11 @@ PHP_FUNCTION(levenshtein)
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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 = weighted_levdist((*str1)->value.str.val
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, (*str2)->value.str.val
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, (*cost_ins)->value.lval
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, (*cost_rep)->value.lval
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, (*cost_del)->value.lval
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distance = reference_levdist((*str1)->value.str.val,(*str1)->value.str.len,
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(*str2)->value.str.val,(*str2)->value.str.len,
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(*cost_ins)->value.lval,
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(*cost_rep)->value.lval,
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(*cost_del)->value.lval
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);
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break;
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54
ext/standard/tests/general_functions/003.phpt
Normal file
54
ext/standard/tests/general_functions/003.phpt
Normal file
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@ -0,0 +1,54 @@
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--TEST--
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levenshtein() function test
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--POST--
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--GET--
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--FILE--
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<?php
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function test_me($title,$expect,$text1,$text2,$cost1=0,$cost2=0,$cost3=0) {
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if($cost1==0)
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$result=levenshtein($text1,$text2);
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else
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$result=levenshtein($text1,$text2,$cost1,$cost2,$cost3);
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if($result==$expect) return 0;
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echo "$title: result is $result instead of $expect ";
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echo "for '$text1'/'$text2' ";
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if($cost1) echo "($cost1:$cost2:$cost3)";
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echo "\n";
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return 1;
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}
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$n=0;
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$n += test_me("equal" , 0, "12345", "12345");
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$n += test_me("1st empty" , 3, "", "xzy");
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$n += test_me("2nd empty" , 3, "xzy", "");
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$n += test_me("both empty" , 0, "", "");
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$n += test_me("1 char" , 1, "1", "2");
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$n += test_me("2 char swap", 2, "12", "21");
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$n += test_me("inexpensive delete", 2, "2121", "11", 2, 1, 1);
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$n += test_me("expensive delete" , 10, "2121", "11", 2, 1, 5);
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$n += test_me("inexpensive insert", 2, "11", "2121", 1, 1, 1);
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$n += test_me("expensive insert" , 10, "11", "2121", 5, 1, 1);
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$n += test_me("expensive replace" , 3, "111", "121", 2, 3, 2);
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$n += test_me("very expensive replace", 4, "111", "121", 2, 9, 2);
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$n += test_me("bug #7368", 2, "13458", "12345");
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$n += test_me("bug #7368", 2, "1345", "1234");
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$n += test_me("bug #6562", 1, "debugg", "debug");
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$n += test_me("bug #6562", 1, "ddebug", "debug");
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$n += test_me("bug #6562", 2, "debbbug", "debug");
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$n += test_me("bug #6562", 1, "debugging", "debuging");
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echo ($n==0)?"all passed\n":"$n failed\n";
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?>
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--EXPECT--
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all passed
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