media/libvpx/vp9/encoder/vp9_treewriter.h@ac0c01689b40
media/libvpx/vp9/encoder/vp9_treewriter.h
Thu, 15 Jan 2015 15:59:08 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 15 Jan 2015 15:59:08 +0100
- branch
- TOR_BUG_9701
- changeset 10
- ac0c01689b40
- permissions
- -rw-r--r--
Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
1 /*
2 * Copyright (c) 2010 The WebM project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
12 #ifndef VP9_ENCODER_VP9_TREEWRITER_H_
13 #define VP9_ENCODER_VP9_TREEWRITER_H_
15 /* Trees map alphabets into huffman-like codes suitable for an arithmetic
16 bit coder. Timothy S Murphy 11 October 2004 */
18 #include "vp9/common/vp9_treecoder.h"
20 #include "vp9/encoder/vp9_boolhuff.h" /* for now */
23 #define vp9_write_prob(w, v) vp9_write_literal((w), (v), 8)
25 /* Approximate length of an encoded bool in 256ths of a bit at given prob */
27 #define vp9_cost_zero(x) (vp9_prob_cost[x])
28 #define vp9_cost_one(x) vp9_cost_zero(vp9_complement(x))
30 #define vp9_cost_bit(x, b) vp9_cost_zero((b) ? vp9_complement(x) : (x))
32 /* VP8BC version is scaled by 2^20 rather than 2^8; see bool_coder.h */
35 /* Both of these return bits, not scaled bits. */
36 static INLINE unsigned int cost_branch256(const unsigned int ct[2],
37 vp9_prob p) {
38 return ct[0] * vp9_cost_zero(p) + ct[1] * vp9_cost_one(p);
39 }
41 static INLINE unsigned int cost_branch(const unsigned int ct[2],
42 vp9_prob p) {
43 return cost_branch256(ct, p) >> 8;
44 }
47 static INLINE void treed_write(vp9_writer *w,
48 vp9_tree tree, const vp9_prob *probs,
49 int bits, int len) {
50 vp9_tree_index i = 0;
52 do {
53 const int bit = (bits >> --len) & 1;
54 vp9_write(w, bit, probs[i >> 1]);
55 i = tree[i + bit];
56 } while (len);
57 }
59 static INLINE void write_token(vp9_writer *w, vp9_tree tree,
60 const vp9_prob *probs,
61 const struct vp9_token *token) {
62 treed_write(w, tree, probs, token->value, token->len);
63 }
65 static INLINE int treed_cost(vp9_tree tree, const vp9_prob *probs,
66 int bits, int len) {
67 int cost = 0;
68 vp9_tree_index i = 0;
70 do {
71 const int bit = (bits >> --len) & 1;
72 cost += vp9_cost_bit(probs[i >> 1], bit);
73 i = tree[i + bit];
74 } while (len);
76 return cost;
77 }
79 static INLINE int cost_token(vp9_tree tree, const vp9_prob *probs,
80 const struct vp9_token *token) {
81 return treed_cost(tree, probs, token->value, token->len);
82 }
84 void vp9_cost_tokens(int *costs, const vp9_prob *probs, vp9_tree tree);
85 void vp9_cost_tokens_skip(int *costs, const vp9_prob *probs, vp9_tree tree);
87 #endif // VP9_ENCODER_VP9_TREEWRITER_H_
