[Freeciv-Dev] (PR#12577) ftwl: faster image_copy_full

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

<URL: http://bugs.freeciv.org/Ticket/Display.html?id=12577 >

image_copy_full is unnecessarily slow because it uses many unnecessary 
memcpy's.  This patch (untested) fixes that.  I suspect it will be quite 
measurably faster.

Note that there's no check for overflow.  There was no check for 
overflow in the old code either.  Nor does the function note that the 
caller needs to check for overflow.  So this function is broken.

-jason

Index: utility/ftwl/be_common_24.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/utility/ftwl/be_common_24.c,v
retrieving revision 1.6
diff -u -r1.6 be_common_24.c
--- utility/ftwl/be_common_24.c 9 Oct 2004 11:59:38 -0000       1.6
+++ utility/ftwl/be_common_24.c 21 Mar 2005 21:38:13 -0000
@@ -570,15 +570,14 @@
   int x, y;
 
   for (y = 0; y < region->height; y++) {
-    for (x = 0; x < region->width; x++) {
-      unsigned char *psrc = IMAGE_GET_ADDRESS(src, x + region->x, 
-                                              y + region->y);
-      unsigned char *pdest = IMAGE_GET_ADDRESS(dest, x, y);
-
-      IMAGE_CHECK(src, x + region->x, y + region->y);
-      IMAGE_CHECK(dest, x, y);
-      memcpy(pdest, psrc, 4);
-    }
+    unsigned char *psrc = IMAGE_GET_ADDRESS(src, region->x, 
+                                           y + region->y);
+    unsigned char *pdest = IMAGE_GET_ADDRESS(dest, 0, y);
+
+    IMAGE_CHECK(src, x + region->x, y + region->y);
+    IMAGE_CHECK(dest, x, y);
+
+    memcpy(pdest, psrc, 4 * region->width);
   }
 }