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/*
* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef __INC_TREECODER_H
#define __INC_TREECODER_H
typedef unsigned char vp9_prob;
#define vp9_prob_half ( (vp9_prob) 128)
typedef signed char vp9_tree_index;
struct bool_coder_spec;
typedef struct bool_coder_spec bool_coder_spec;
typedef struct bool_writer bool_writer;
typedef struct bool_reader bool_reader;
typedef const bool_coder_spec c_bool_coder_spec;
typedef const bool_writer c_bool_writer;
typedef const bool_reader c_bool_reader;
# define vp9_complement( x) (255 - x)
/* We build coding trees compactly in arrays.
Each node of the tree is a pair of vp9_tree_indices.
Array index often references a corresponding probability table.
Index <= 0 means done encoding/decoding and value = -Index,
Index > 0 means need another bit, specification at index.
Nonnegative indices are always even; processing begins at node 0. */
typedef const vp9_tree_index vp9_tree[], *vp9_tree_p;
typedef const struct vp9_token_struct {
int value;
int Len;
} vp9_token;
/* Construct encoding array from tree. */
void vp9_tokens_from_tree(struct vp9_token_struct *, vp9_tree);
void vp9_tokens_from_tree_offset(struct vp9_token_struct *, vp9_tree,
int offset);
/* Convert array of token occurrence counts into a table of probabilities
for the associated binary encoding tree. Also writes count of branches
taken for each node on the tree; this facilitiates decisions as to
probability updates. */
void vp9_tree_probs_from_distribution(
int n, /* n = size of alphabet */
vp9_token tok [ /* n */ ],
vp9_tree tree,
vp9_prob probs [ /* n-1 */ ],
unsigned int branch_ct [ /* n-1 */ ] [2],
const unsigned int num_events[ /* n */ ],
unsigned int Pfactor,
int Round
);
static __inline int clip_prob(int p) {
if (p > 255)
return 255;
else if (p < 1)
return 1;
return p;
}
vp9_prob vp9_bin_prob_from_distribution(const unsigned int counts[2]);
#endif
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