[Mono-list] Patch for String.Replace

[Jackson Harper]

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On Mon, 2003-08-18 at 04:36, Jonathan Pryor wrote:
> Perhaps I'm missing something, but your patch could be much simpler. 
> All you need to do is, before the "ret = mono_string_new_size(...)" line
> (line 351), have this:
> 
> 	if (occur == 0)
> 		return me;

	The occurr variable is only modified if the string being replaced is
not the same size as the replacement string. 

	I can use your check if the strings are a different size though.
Attached is a new patch.

Jackson

> 
> Since "occur" keeps track of how many times "oldValue" occurs within
> "me", if occur is 0, you don't need to do any processing at all.  This
> would require no changes to the loop as well.
> 
>  - Jon
> 
> On Mon, 2003-08-18 at 11:30, Jackson Harper wrote:
> > Hello,
> > 
> > 	Attached is a patch that changes the behavoir of String.Replace. If the
> > replace method does not alter the string at all it returns a reference
> > to the unaltered string. I have been told on #mono that this is what is
> > happening on MS. Would be great if some more people can confirm this.
> > 
> > 	I've also attached a test case that I will integrate into the unit
> > tests if someone can confirm that this is the same behavoir as MS.
> > 
> > 
> > Jackson
> > 
> > 
> 

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Index: string-icalls.c
===================================================================
RCS file: /cvs/public/mono/mono/metadata/string-icalls.c,v
retrieving revision 1.22
diff -u -r1.22 string-icalls.c
--- string-icalls.c	11 May 2003 23:52:40 -0000	1.22
+++ string-icalls.c	20 Aug 2003 03:05:33 -0000
@@ -343,28 +343,36 @@
 		for (i = 0; i <= srclen - oldstrlen; i++)
 			if (0 == memcmp(src + i, oldstr, oldstrlen * sizeof(gunichar2)))
 				occurr++;
-
+                if (occurr == 0)
+                        return me;
 		newsize = srclen + ((newstrlen - oldstrlen) * occurr);
  	} else
 		newsize = srclen;
 
-	ret = mono_string_new_size( mono_domain_get (), newsize);
-	dest = mono_string_chars(ret);
-
+        ret = NULL;
 	i = 0;
 	while (i < srclen) {
 		if (0 == memcmp(src + i, oldstr, oldstrlen * sizeof(gunichar2))) {
+                        if (ret == NULL) {
+                                ret = mono_string_new_size( mono_domain_get (), newsize);
+                                dest = mono_string_chars(ret);
+                                memcpy (dest, src, i * sizeof(gunichar2));
+                        }
 			if (newstrlen > 0) {
 				memcpy(dest + destpos, newstr, newstrlen * sizeof(gunichar2));
 				destpos += newstrlen;
 			}
 			i += oldstrlen;
-		} else {
+                        continue;
+		} else if (ret != NULL) {
 			dest[destpos] = src[i];
+ 		}
 			destpos++;
 			i++;
 		}
-	}
+        
+        if (ret == NULL)
+                return me;
 
 	return ret;
 }

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