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stb_image: Keep zout in a local var during stbi__parse_huffman_block.

This commit is contained in:
Fabian Giesen 2014-12-13 17:58:36 -08:00
parent 8188e842e2
commit 92b9e262b7
1 changed files with 20 additions and 9 deletions
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29
stb_image.h
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@ -2146,10 +2146,11 @@ stbi_inline static int stbi__zhuffman_decode(stbi__zbuf *a, stbi__zhuffman *z)
return z->value[b];
}
static int stbi__zexpand(stbi__zbuf *z, int n) // need to make room for n bytes
static int stbi__zexpand(stbi__zbuf *z, char *zout, int n) // need to make room for n bytes
{
char *q;
int cur, limit;
z->zout = zout;
if (!z->z_expandable) return stbi__err("output buffer limit","Corrupt PNG");
cur = (int) (z->zout - z->zout_start);
limit = (int) (z->zout_end - z->zout_start);
@ -2179,16 +2180,23 @@ static int stbi__zdist_extra[32] =
static int stbi__parse_huffman_block(stbi__zbuf *a)
{
char *zout = a->zout;
for(;;) {
int z = stbi__zhuffman_decode(a, &a->z_length);
if (z < 256) {
if (z < 0) return stbi__err("bad huffman code","Corrupt PNG"); // error in huffman codes
if (a->zout >= a->zout_end) if (!stbi__zexpand(a, 1)) return 0;
*a->zout++ = (char) z;
if (zout >= a->zout_end) {
if (!stbi__zexpand(a, zout, 1)) return 0;
zout = a->zout;
}
*zout++ = (char) z;
} else {
stbi_uc *p;
int len,dist;
if (z == 256) return 1;
if (z == 256) {
a->zout = zout;
return 1;
}
z -= 257;
len = stbi__zlength_base[z];
if (stbi__zlength_extra[z]) len += stbi__zreceive(a, stbi__zlength_extra[z]);
@ -2196,11 +2204,14 @@ static int stbi__parse_huffman_block(stbi__zbuf *a)
if (z < 0) return stbi__err("bad huffman code","Corrupt PNG");
dist = stbi__zdist_base[z];
if (stbi__zdist_extra[z]) dist += stbi__zreceive(a, stbi__zdist_extra[z]);
if (a->zout - a->zout_start < dist) return stbi__err("bad dist","Corrupt PNG");
if (a->zout + len > a->zout_end) if (!stbi__zexpand(a, len)) return 0;
p = (stbi_uc *) (a->zout - dist);
if (zout - a->zout_start < dist) return stbi__err("bad dist","Corrupt PNG");
if (zout + len > a->zout_end) {
if (!stbi__zexpand(a, zout, len)) return 0;
zout = a->zout;
}
p = (stbi_uc *) (zout - dist);
while (len--)
*a->zout++ = *p++;
*zout++ = *p++;
}
}
}
@ -2273,7 +2284,7 @@ static int stbi__parse_uncomperssed_block(stbi__zbuf *a)
if (nlen != (len ^ 0xffff)) return stbi__err("zlib corrupt","Corrupt PNG");
if (a->zbuffer + len > a->zbuffer_end) return stbi__err("read past buffer","Corrupt PNG");
if (a->zout + len > a->zout_end)
if (!stbi__zexpand(a, len)) return 0;
if (!stbi__zexpand(a, a->zout, len)) return 0;
memcpy(a->zout, a->zbuffer, len);
a->zbuffer += len;
a->zout += len;