/* *  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 VPX_VP8_ENCODER_TREEWRITER_H_#define VPX_VP8_ENCODER_TREEWRITER_H_ /* Trees map alphabets into huffman-like codes suitable for an arithmetic   bit coder.  Timothy S Murphy  11 October 2004 */ #include <stdint.h> #include "./vpx_config.h"#include "vp8/common/treecoder.h" #include "boolhuff.h" /* for now */ #ifdef __cplusplusextern "C" {#endif typedef BOOL_CODER vp8_writer; #define vp8_write vp8_encode_bool#define vp8_write_literal vp8_encode_value#define vp8_write_bit(W, V) vp8_write(W, V, vp8_prob_half) #define vp8bc_write vp8bc_write_bool#define vp8bc_write_literal vp8bc_write_bits#define vp8bc_write_bit(W, V) vp8bc_write_bits(W, V, 1) /* Approximate length of an encoded bool in 256ths of a bit at given prob */ #define vp8_cost_zero(x) (vp8_prob_cost[x])#define vp8_cost_one(x) vp8_cost_zero(vp8_complement(x)) #define vp8_cost_bit(x, b) vp8_cost_zero((b) ? vp8_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 vp8_cost_branch(const unsigned int ct[2],                                           vp8_prob p) {  /* Imitate existing calculation */   return (unsigned int)(((((uint64_t)ct[0]) * vp8_cost_zero(p)) +                         (((uint64_t)ct[1]) * vp8_cost_one(p))) >>                        8);} /* Small functions to write explicit values and tokens, as well as   estimate their lengths. */ static void vp8_treed_write(vp8_writer *const w, vp8_tree t,                            const vp8_prob *const p, int v,                            int n) { /* number of bits in v, assumed nonzero */  vp8_tree_index i = 0;   do {    const int b = (v >> --n) & 1;    vp8_write(w, b, p[i >> 1]);    i = t[i + b];  } while (n);}static INLINE void vp8_write_token(vp8_writer *const w, vp8_tree t,                                   const vp8_prob *const p,                                   vp8_token *const x) {  vp8_treed_write(w, t, p, x->value, x->Len);} static int vp8_treed_cost(vp8_tree t, const vp8_prob *const p, int v,                          int n) { /* number of bits in v, assumed nonzero */  int c = 0;  vp8_tree_index i = 0;   do {    const int b = (v >> --n) & 1;    c += vp8_cost_bit(p[i >> 1], b);    i = t[i + b];  } while (n);   return c;}static INLINE int vp8_cost_token(vp8_tree t, const vp8_prob *const p,                                 vp8_token *const x) {  return vp8_treed_cost(t, p, x->value, x->Len);} /* Fill array of costs for all possible token values. */ void vp8_cost_tokens(int *c, const vp8_prob *, vp8_tree); void vp8_cost_tokens2(int *c, const vp8_prob *, vp8_tree, int); #ifdef __cplusplus}  // extern "C"#endif #endif  // VPX_VP8_ENCODER_TREEWRITER_H_