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Code Issues Releases Activity

(gif_load): Avoid sign extension and thus out of bounds

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color indices when accessing raster pixels.
This commit is contained in:
Gerd Moellmann 2000-01-01 00:04:52 +00:00
parent 40891308b8
commit 9b784e9676
2 changed files with 13 additions and 4 deletions
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5
src/ChangeLog
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@ -1,3 +1,8 @@
2000-01-01 Gerd Moellmann <gerd@gnu.org>
* xfns.c (gif_load): Avoid sign extension and thus out of bounds
color indices when accessing raster pixels.
1999-12-31 Gerd Moellmann <gerd@gnu.org>
* xfns.c: New image functions adapted to Emacs conventions.

12
src/xfns.c
View File

@ -9207,6 +9207,7 @@ gif_load (f, img)
Lisp_Object image;
int ino, image_left, image_top, image_width, image_height;
gif_memory_source memsrc;
unsigned char *raster;
specified_file = image_spec_value (img->spec, QCfile, NULL);
specified_data = image_spec_value (img->spec, QCdata, NULL);
@ -9327,7 +9328,11 @@ gif_load (f, img)
XPutPixel (ximg, x, y, FRAME_BACKGROUND_PIXEL (f));
}
/* Read the GIF image into the X image. */
/* Read the GIF image into the X image. We use a local variable
`raster' here because RasterBits below is a char *, and invites
problems with bytes >= 0x80. */
raster = (unsigned char *) gif->SavedImages[ino].RasterBits;
if (gif->SavedImages[ino].ImageDesc.Interlace)
{
static int interlace_start[] = {0, 4, 2, 1};
@ -9348,8 +9353,7 @@ gif_load (f, img)
for (x = 0; x < image_width; x++)
{
unsigned int i
= gif->SavedImages[ino].RasterBits[(y * image_width) + x];
int i = raster[(y * image_width) + x];
XPutPixel (ximg, x + image_left, row + image_top,
pixel_colors[i]);
}
@ -9362,7 +9366,7 @@ gif_load (f, img)
for (y = 0; y < image_height; ++y)
for (x = 0; x < image_width; ++x)
{
unsigned i = gif->SavedImages[ino].RasterBits[y * image_width + x];
int i = raster[y * image_width + x];
XPutPixel (ximg, x + image_left, y + image_top, pixel_colors[i]);
}
}