Commit 8aaf5ec4 authored by James Zern's avatar James Zern

vp9_dsubexp: remove clamp in inv_remap_prob()

the max value of the lookup in expanded form is:
(((1 << 7) - 1) << 1) - 65 + 1 + 64 = 254

remove the clamp [0, 253] and add one table entry

Change-Id: I0b5d0c66702fdb0b8f1cc9ab9b0dac66326e85a6
parent fc5f3b8f
......@@ -8,6 +8,8 @@
* be found in the AUTHORS file in the root of the source tree.
*/
#include <assert.h>
#include "vp9/common/vp9_entropy.h"
#include "vp9/decoder/vp9_dsubexp.h"
......@@ -27,7 +29,7 @@ static int decode_uniform(vp9_reader *r) {
}
static int inv_remap_prob(int v, int m) {
static int inv_map_table[MAX_PROB - 1] = {
static int inv_map_table[MAX_PROB] = {
6, 19, 32, 45, 58, 71, 84, 97, 110, 123, 136, 149, 162, 175, 188,
201, 214, 227, 240, 253, 0, 1, 2, 3, 4, 5, 7, 8, 9, 10,
11, 12, 13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 26,
......@@ -44,11 +46,9 @@ static int inv_remap_prob(int v, int m) {
190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 202, 203, 204, 205,
206, 207, 208, 209, 210, 211, 212, 213, 215, 216, 217, 218, 219, 220, 221,
222, 223, 224, 225, 226, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237,
238, 239, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252
238, 239, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 252
};
// The clamp is not necessary for conforming VP9 stream, it is added to
// prevent out of bound access for bad input data
v = clamp(v, 0, 253);
assert(v < (int)(sizeof(inv_map_table) / sizeof(inv_map_table[0])));
v = inv_map_table[v];
m--;
if ((m << 1) <= MAX_PROB) {
......
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