# HG changeset patch
# User Sam Lantinga <slouken@libsdl.org>
# Date 1101824900 0
# Node ID 3bf4103b2b89b8d1c01836b09ccdf999d15e4051
# Parent  54bb194550811279b1cb134889b044201cced357
Date: Sat, 27 Nov 2004 13:35:43 +0100
From: "Martin Bickel"
Subject: [SDL] Patch: fixing uninitilized palette

while running Valgrind over my application I found the following
problem in SDL:

The function MapNto1 allocates  SDL_Color colors[256]  but does not
initialize it.
SDL_DitherColors is then called which initialized the r, g and b
component, but not the 'unused' component of each color.
When Map1to1 is called from MapNto1, it runs a memcmp on the colors,
which also evaluates the unused component and therefor returns
differences much more often than necessary.

So the 'unused' component of SDL_Color should be initialized. This
patch does this by calling memset for the whole array in MapNto1 .

diff -r 54bb19455081 -r 3bf4103b2b89 src/video/SDL_pixels.c
--- a/src/video/SDL_pixels.c	Tue Nov 30 13:04:22 2004 +0000
+++ b/src/video/SDL_pixels.c	Tue Nov 30 14:28:20 2004 +0000
@@ -494,6 +494,10 @@
 	/* Generate a 256 color dither palette */
 	SDL_Palette dithered;
 	SDL_Color colors[256];
+	
+	/* SDL_DitherColors does not initialize the 'unused' component of colors,
+	   but Map1to1 compares it against dst, so we should initialize it. */  
+	memset(colors, 0, sizeof(colors));
 
 	dithered.ncolors = 256;
 	SDL_DitherColors(colors, 8);