The Tor Browser: media/libvpx/vp9/encoder/vp9

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

     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_

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