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Date: Wed, 09 Jun 2004 13:52:42 +0300
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Subject: Re: [PHP-DEV] stripslashes() improvements
From: valyala@tut.by ("Alexander Valyalkin")

On Tue, 8 Jun 2004 16:03:19 +0200 (CEST), Derick Rethans <derick@php.net>  
wrote:

>
> You'll have to proof that by writing testcases, for example try it with
> the test cases in the current source and write new ones for things that
> we don't have a test case for yet.
>
>> -PHPAPI void php_stripslashes(char *str, int *len TSRMLS_DC)
>> +PHPAPI void php_stripslashes(char *str, size_t *len TSRMLS_DC)
>
> You can't just change the API call, that will break things.
>
>
> regards,
> Derick

Ok. First of all, my version of the stripslashes() solves following bugs:
#9437
#19947
#27848

I have successfully tested my code with test case from current source
/ext/standard/tests/strings/add-and-stripslashes.phpt

And here is my testcase, related to mentioned bugs:

<?php
echo "Stripslashes test: ";
ini_set('magic_quotes_sybase', 0);
$s = 'c:\\windows\\system32';
$s1 = '\\';
if ($s == stripslashes($s) && $s1 == stripslashes($s1)) echo "OK\n";
else echo "FAILED\n";
?>

Here is corrected code with standart API call:
====================cut======================
PHPAPI void php_stripslashes(char *str, int *len TSRMLS_DC)
{
     char *s, *t;
     size_t l;
     size_t dst_len; /* length of the stripped string */

     if (len != NULL) l = dst_len = (size_t) *len;
     else l = dst_len = strlen(str);
     if (l < 2) return; /* there is no characters to strip */
     s = t = str;

     if (PG(magic_quotes_sybase)) { /* sybase magic_quotes ( '' -> ', \0 ->  
NULL) */
         while (l > 1) {
             if (*t == '\'' && *(t + 1) == '\'') {
                 *s++ = '\'';
                 t += 2;
                 l--;
                 dst_len--;
             } else if (*t == '\\' && *(t + 1) == '0') {
                 *s++ = '\0';
                 t += 2;
                 l--;
                 dst_len--;
             } else *s++ = *t++;
             l--;
         }
     } else { /* ordinary magic_qoutes (not sybase) ( \\ -> \, \' -> ', \"  
-> ", \0 -> NULL) */
         while (l > 1) {
             if (*t == '\\') {
                 t++;
                 switch (*t) {
                     case '\\' :
                     case '\'' :
                     case '"' :
                         *s++ = *t++; dst_len--; break;
                     case '0' : *s++ = '\0'; t++; dst_len--; break;
                     default : *s++ = '\\'; *s++ = *t++; break;
                 }
                 l -= 2;
             } else {
                 *s++ = *t++;
                 l--;
             }
         }
     }
     if (l == 1) *s++ = *t; /* copy the last symbol */
     if (len != NULL) *len = (int) dst_len; /* set length of the stripped  
string */
     *s = '\0';
}
====================cut======================

diff:
====================cut======================
--- string.c    Thu May 13 20:44:32 2004
+++ string_new.c    Wed Jun 09 13:47:21 2004
@@ -2159,70 +2159,51 @@
  PHPAPI void php_stripslashes(char *str, int *len TSRMLS_DC)
  {
     char *s, *t;
-   int l;
-
-   if (len != NULL) {
-       l = *len;
-   } else {
-       l = strlen(str);
-   }
-   s = str;
-   t = str;
+    size_t l;
+    size_t dst_len; /* length of the stripped string */

-   if (PG(magic_quotes_sybase)) {
-       while (l > 0) {
-           if (*t == '\'') {
-               if ((l > 0) && (t[1] == '\'')) {
-                   t++;
-                   if (len != NULL)
-                       (*len)--;
+    if (len != NULL) l = dst_len = (size_t) *len;
+    else l = dst_len = strlen(str);
+    if (l < 2) return; /* there is no characters to strip */
+    s = t = str;
+
+    if (PG(magic_quotes_sybase)) { /* sybase magic_quotes ( '' -> ', \0  
-> NULL) */
+        while (l > 1) {
+            if (*t == '\'' && *(t + 1) == '\'') {
+                *s++ = '\'';
+                t += 2;
                     l--;
-               }
-               *s++ = *t++;
-           } else if (*t == '\\' && l > 0 && t[1] == '0') {
+                dst_len--;
+            } else if (*t == '\\' && *(t + 1) == '0') {
                     *s++='\0';
                     t += 2;
-                   if (len != NULL)
-                       (*len)--;
                     l--;
-           } else {
-               *s++ = *t++;
-           }
+                dst_len--;
+            } else *s++ = *t++;
             l--;
         }
-       *s = '\0';
-
-       return;
-   }
-
-   while (l > 0) {
+    } else { /* ordinary magic_qoutes (not sybase) ( \\ -> \, \' -> ', \"  
-> ", \0 -> NULL) */
+        while (l > 1) {
         if (*t == '\\') {
-           t++;                /* skip the slash */
-           if (len != NULL)
-               (*len)--;
-           l--;
-           if (l > 0) {
-               if (*t == '0') {
-                   *s++='\0';
                     t++;
-               } else {
-                   *s++ = *t++;    /* preserve the next character */
-               }
-               l--;
+                switch (*t) {
+                    case '\\' :
+                    case '\'' :
+                    case '"' :
+                        *s++ = *t++; dst_len--; break;
+                    case '0' : *s++ = '\0'; t++; dst_len--; break;
+                    default : *s++ = '\\'; *s++ = *t++; break;
             }
+                l -= 2;
         } else {
-           if (s != t) {
                 *s++ = *t++;
-           } else {
-               s++;
-               t++;
-           }
             l--;
         }
     }
-   if (s != t) {
-       *s = '\0';
     }
+    if (l == 1) *s++ = *t; /* copy the last symbol */
+    if (len != NULL) *len = (int) dst_len; /* set length of the stripped  
string */
+    *s = '\0';
  }
  /* }}} */
====================cut======================
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