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Date: Sat, 27 Nov 2004 13:35:43 +0100

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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 .

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40998
This commit is contained in:
Sam Lantinga 2004-11-30 14:28:20 +00:00
parent ef0cced667
commit ca383efa22
1 changed files with 4 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

4
src/video/SDL_pixels.c
View file

@ -495,6 +495,10 @@ static Uint8 *MapNto1(SDL_PixelFormat *src, SDL_Palette *dst, int *identical)
SDL_Palette dithered; SDL_Palette dithered;
SDL_Color colors[256]; 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; dithered.ncolors = 256;
SDL_DitherColors(colors, 8); SDL_DitherColors(colors, 8);
dithered.colors = colors; dithered.colors = colors;