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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_TREEWRITER_H
#define __INC_TREEWRITER_H
/* Trees map alphabets into huffman-like codes suitable for an arithmetic
bit coder. Timothy S Murphy 11 October 2004 */
#include "vp9/common/vp9_treecoder.h"
#include "vp9_boolhuff.h" /* for now */
typedef BOOL_CODER vp9_writer;
#define vp9_write encode_bool
#define vp9_write_literal vp9_encode_value
#define vp9_write_bit(W, V) vp9_write(W, V, vp9_prob_half)
/* Approximate length of an encoded bool in 256ths of a bit at given prob */
#define vp9_cost_zero(x) (vp9_prob_cost[x])
#define vp9_cost_one(x) vp9_cost_zero(vp9_complement(x))
#define vp9_cost_bit(x, b) vp9_cost_zero((b) ? vp9_complement(x) : (x))
/* VP8BC version is scaled by 2^20 rather than 2^8; see bool_coder.h */
/* Both of these return bits, not scaled bits. */
static __inline unsigned int cost_branch(const unsigned int ct[2],
vp9_prob p) {
/* Imitate existing calculation */
return ((ct[0] * vp9_cost_zero(p))
+ (ct[1] * vp9_cost_one(p))) >> 8;
}
static __inline unsigned int cost_branch256(const unsigned int ct[2],
vp9_prob p) {
/* Imitate existing calculation */
return ((ct[0] * vp9_cost_zero(p))
+ (ct[1] * vp9_cost_one(p)));
}
/* Small functions to write explicit values and tokens, as well as
estimate their lengths. */
static __inline void treed_write(vp9_writer *const w,
vp9_tree t,
const vp9_prob *const p,
int v,
/* number of bits in v, assumed nonzero */
int n) {
vp9_tree_index i = 0;
do {
const int b = (v >> --n) & 1;
vp9_write(w, b, p[i >> 1]);
i = t[i + b];
} while (n);
}
static __inline void write_token(vp9_writer *const w,
vp9_tree t,
const vp9_prob *const p,
vp9_token *const x) {
treed_write(w, t, p, x->value, x->Len);
}
static __inline int treed_cost(vp9_tree t,
const vp9_prob *const p,
int v,
/* number of bits in v, assumed nonzero */
int n) {
int c = 0;
vp9_tree_index i = 0;
do {
const int b = (v >> --n) & 1;
c += vp9_cost_bit(p[i >> 1], b);
i = t[i + b];
} while (n);
return c;
}
static __inline int cost_token(vp9_tree t,
const vp9_prob *const p,
vp9_token *const x) {
return treed_cost(t, p, x->value, x->Len);
}
/* Fill array of costs for all possible token values. */
void vp9_cost_tokens(int *Costs, const vp9_prob *, vp9_tree);
void vp9_cost_tokens_skip(int *c, const vp9_prob *p, vp9_tree t);
#endif
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