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 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;
}