/*
NETSCAPE2.0
http://odur.let.rug.nl/~kleiweg/gif/netscape.html
http://www.vurdalakov.net/misc/gif/netscape-looping-application-extension
http://www.vurdalakov.net/misc/gif/netscape-buffering-application-extension
https://code.google.com/p/gifdotnet/source/browse/src/GifDotNet/GifApplicationExtensionBlock.cs#95
http://trac.webkit.org/browser/trunk/Source/WebCore/platform/image-decoders/gif/GIFImageReader.cpp#L617
ANIMEXTS1.0
http://www.vurdalakov.net/misc/gif/animexts-looping-application-extension
https://code.google.com/p/gifdotnet/source/browse/src/GifDotNet/GifApplicationExtensionBlock.cs#95
ICCRGBG1012
http://www.color.org/icc1V42.pdf
XMP DataXMP
http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/en/devnet/xmp/pdfs/XMPSpecificationPart3.pdf
fractint
http://fractint.net/fractsvn/trunk/fractint/common/loadfile.c
ZGATEXTI5 ZGATILEI5 ZGACTRLI5 ZGANPIMGI5
ZGAVECTI5 ZGAALPHAI5 ZGATITLE4.0 ZGATEXTI4.0
Zoner GIF animator 4.0 and 5.0
*/
static unsigned char *
gif_read_ae(fz_context *ctx, struct info *info, unsigned char *p, unsigned char *end)
{
static char *ignorable[] = {
"NETSACPE2.0", "ANIMEXTS1.0", "ICCRGBG1012", "XMP DataXMP",
"ZGATEXTI5\0\0", "ZGATILEI5\0\0", "ZGANPIMGI5\0", "ZGACTRLI5\0\0",
"ZGAVECTI5\0\0", "ZGAALPHAI5\0", "ZGATITLE4.0", "ZGATEXTI4.0",
};
int i, ignored;
if (end - p < 14)
fz_throw(ctx, FZ_ERROR_GENERIC, "premature end in application extension in gif image");
if (p[2] != 0x0b)
fz_throw(ctx, FZ_ERROR_GENERIC, "out of range application extension block size in gif image");
ignored = 0;
for (i = 0; i < nelem(ignorable); i++)
ignored |= memcmp(&p[3], ignorable[i], 8 + 3);
if (!ignored)
{
char extension[9];
memmove(extension, &p[3], 8);
extension[8] = '\0';
fz_warn(ctx, "ignoring unsupported application extension '%s' in gif image", extension);
}
return gif_read_subblocks(ctx, info, p + 14, end, NULL);
}
static unsigned char*
gif_read_pte(fz_context *ctx, struct info *info, unsigned char *p, unsigned char *end)
{
if (end - p < 15)
fz_throw(ctx, FZ_ERROR_GENERIC, "premature end in plain text extension in gif image");
if (p[2] != 0x0c)
fz_throw(ctx, FZ_ERROR_GENERIC, "out of range plain text extension block size in gif image");
return gif_read_subblocks(ctx, info, p + 15, end, NULL);
}
static unsigned char *
gif_read_tbid(fz_context *ctx, struct info *info, unsigned char *dest, unsigned char *p, unsigned char *end)
{
fz_stream *stm, *lzwstm = NULL;
unsigned int mincodesize, y;
fz_buffer *compressed = NULL, *uncompressed = NULL;
const unsigned char *ct;
unsigned char *sp;
if (end - p < 1)
fz_throw(ctx, FZ_ERROR_GENERIC, "premature end in table based image data in gif image");
mincodesize = *p;
fz_var(compressed);
fz_var(lzwstm);
fz_var(uncompressed);
fz_try(ctx)
{
compressed = fz_new_buffer(ctx, 0);
p = gif_read_subblocks(ctx, info, p + 1, end, compressed);
stm = fz_open_buffer(ctx, compressed);
lzwstm = fz_open_lzwd(ctx, stm, 0, mincodesize + 1, 1, 0);
uncompressed = fz_read_all(ctx, lzwstm, info->width * info->height);
sp = uncompressed->data;
if (info->has_lct)
ct = info->lct;
else if (info->has_gct)
ct = info->gct;
else
ct = dct;
if (info->image_interlaced)
{
for (y = 0; y < info->image_height; y += 8, sp += info->image_width)
gif_read_line(ctx, info, dest, ct, y, sp);
for (y = 4; y < info->image_height; y += 8, sp += info->image_width)
gif_read_line(ctx, info, dest, ct, y, sp);
for (y = 2; y < info->image_height; y += 4, sp += info->image_width)
gif_read_line(ctx, info, dest, ct, y, sp);
for (y = 1; y < info->image_height; y += 2, sp += info->image_width)
gif_read_line(ctx, info, dest, ct, y, sp);
}
else
for (y = 0; y < info->image_height; y++, sp += info->image_width)
gif_read_line(ctx, info, dest, ct, y, sp);
}
fz_always(ctx)
{
fz_drop_buffer(ctx, uncompressed);
fz_drop_buffer(ctx, compressed);
fz_drop_stream(ctx, lzwstm);
}
fz_catch(ctx)
{
fz_rethrow(ctx);
}
return p;
}
static unsigned char *
gif_read_ce(fz_context *ctx, struct info *info, unsigned char *p, unsigned char *end)
{
return gif_read_subblocks(ctx, info, p + 2, end, NULL);
}
static const unsigned char *
gif_read_tbid(fz_context *ctx, struct info *info, unsigned char *dest, const unsigned char *p, const unsigned char *end)
{
fz_stream *stm, *lzwstm = NULL;
unsigned int mincodesize, y;
fz_buffer *compressed = NULL, *uncompressed = NULL;
const unsigned char *ct;
unsigned char *sp;
int ct_entries;
if (end - p < 1)
fz_throw(ctx, FZ_ERROR_GENERIC, "premature end in table based image data in gif image");
mincodesize = *p;
/* if there is no overlap, avoid pasting image data, just consume it */
if (info->image_top >= info->height || info->image_left >= info->width)
{
p = gif_read_subblocks(ctx, info, p + 1, end, NULL);
return p;
}
fz_var(compressed);
fz_var(lzwstm);
fz_var(uncompressed);
fz_try(ctx)
{
compressed = fz_new_buffer(ctx, 0);
p = gif_read_subblocks(ctx, info, p + 1, end, compressed);
stm = fz_open_buffer(ctx, compressed);
lzwstm = fz_open_lzwd(ctx, stm, 0, mincodesize + 1, 1, 1);
uncompressed = fz_read_all(ctx, lzwstm, 0);
if (uncompressed->len < info->image_width * info->image_height)
fz_throw(ctx, FZ_ERROR_GENERIC, "premature end in compressed table based image data in gif image");
if (info->has_lct)
{
ct = info->lct;
ct_entries = info->lct_entries;
}
else if (info->has_gct)
{
ct = info->gct;
ct_entries = info->gct_entries;
}
else
{
ct = dct;
ct_entries = 256;
}
sp = uncompressed->data;
if (info->image_interlaced)
{
for (y = 0; y < info->image_height; y += 8, sp += info->image_width)
gif_read_line(ctx, info, dest, ct_entries, ct, y, sp);
for (y = 4; y < info->image_height; y += 8, sp += info->image_width)
gif_read_line(ctx, info, dest, ct_entries, ct, y, sp);
for (y = 2; y < info->image_height; y += 4, sp += info->image_width)
gif_read_line(ctx, info, dest, ct_entries, ct, y, sp);
for (y = 1; y < info->image_height; y += 2, sp += info->image_width)
gif_read_line(ctx, info, dest, ct_entries, ct, y, sp);
}
else
for (y = 0; y < info->image_height; y++, sp += info->image_width)
gif_read_line(ctx, info, dest, ct_entries, ct, y, sp);
}
fz_always(ctx)
{
fz_drop_buffer(ctx, uncompressed);
fz_drop_buffer(ctx, compressed);
fz_drop_stream(ctx, lzwstm);
}
fz_catch(ctx)
{
fz_rethrow(ctx);
}
return p;
}
