/* *  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 vp8bc_index_t; /* probability index */  typedef unsigned char vp8_prob; #define vp8_prob_half ( (vp8_prob) 128) typedef signed char vp8_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 vp8_complement( x) (255 - x)  /* We build coding trees compactly in arrays.   Each node of the tree is a pair of vp8_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 vp8_tree_index vp8_tree[], *vp8_tree_p;  typedef const struct vp8_token_struct{    int value;    int Len;} vp8_token; /* Construct encoding array from tree. */ void vp8_tokens_from_tree(struct vp8_token_struct *, vp8_tree);void vp8_tokens_from_tree_offset(struct vp8_token_struct *, vp8_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 vp8_tree_probs_from_distribution(    int n,                      /* n = size of alphabet */    vp8_token tok               [ /* n */ ],    vp8_tree tree,    vp8_prob probs          [ /* n-1 */ ],    unsigned int branch_ct       [ /* n-1 */ ] [2],    const unsigned int num_events[ /* n */ ],    unsigned int Pfactor,    int Round); /* Variant of above using coder spec rather than hardwired 8-bit probs. */ void vp8bc_tree_probs_from_distribution(    int n,                      /* n = size of alphabet */    vp8_token tok               [ /* n */ ],    vp8_tree tree,    vp8_prob probs          [ /* n-1 */ ],    unsigned int branch_ct       [ /* n-1 */ ] [2],    const unsigned int num_events[ /* n */ ],    c_bool_coder_spec *s);  #endif