michael@0: /*
michael@0:  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
michael@0:  *
michael@0:  *  Use of this source code is governed by a BSD-style license
michael@0:  *  that can be found in the LICENSE file in the root of the source
michael@0:  *  tree. An additional intellectual property rights grant can be found
michael@0:  *  in the file PATENTS.  All contributing project authors may
michael@0:  *  be found in the AUTHORS file in the root of the source tree.
michael@0:  */
michael@0: 
michael@0: 
michael@0: #ifndef __INC_TREECODER_H
michael@0: #define __INC_TREECODER_H
michael@0: 
michael@0: typedef unsigned char vp8bc_index_t; /* probability index */
michael@0: 
michael@0: 
michael@0: typedef unsigned char vp8_prob;
michael@0: 
michael@0: #define vp8_prob_half ( (vp8_prob) 128)
michael@0: 
michael@0: typedef signed char vp8_tree_index;
michael@0: struct bool_coder_spec;
michael@0: 
michael@0: typedef struct bool_coder_spec bool_coder_spec;
michael@0: typedef struct bool_writer bool_writer;
michael@0: typedef struct bool_reader bool_reader;
michael@0: 
michael@0: typedef const bool_coder_spec c_bool_coder_spec;
michael@0: typedef const bool_writer c_bool_writer;
michael@0: typedef const bool_reader c_bool_reader;
michael@0: 
michael@0: 
michael@0: 
michael@0: # define vp8_complement( x) (255 - x)
michael@0: 
michael@0: 
michael@0: /* We build coding trees compactly in arrays.
michael@0:    Each node of the tree is a pair of vp8_tree_indices.
michael@0:    Array index often references a corresponding probability table.
michael@0:    Index <= 0 means done encoding/decoding and value = -Index,
michael@0:    Index > 0 means need another bit, specification at index.
michael@0:    Nonnegative indices are always even;  processing begins at node 0. */
michael@0: 
michael@0: typedef const vp8_tree_index vp8_tree[], *vp8_tree_p;
michael@0: 
michael@0: 
michael@0: typedef const struct vp8_token_struct
michael@0: {
michael@0:     int value;
michael@0:     int Len;
michael@0: } vp8_token;
michael@0: 
michael@0: /* Construct encoding array from tree. */
michael@0: 
michael@0: void vp8_tokens_from_tree(struct vp8_token_struct *, vp8_tree);
michael@0: void vp8_tokens_from_tree_offset(struct vp8_token_struct *, vp8_tree,
michael@0:                                  int offset);
michael@0: 
michael@0: 
michael@0: /* Convert array of token occurrence counts into a table of probabilities
michael@0:    for the associated binary encoding tree.  Also writes count of branches
michael@0:    taken for each node on the tree; this facilitiates decisions as to
michael@0:    probability updates. */
michael@0: 
michael@0: void vp8_tree_probs_from_distribution(
michael@0:     int n,                      /* n = size of alphabet */
michael@0:     vp8_token tok               [ /* n */ ],
michael@0:     vp8_tree tree,
michael@0:     vp8_prob probs          [ /* n-1 */ ],
michael@0:     unsigned int branch_ct       [ /* n-1 */ ] [2],
michael@0:     const unsigned int num_events[ /* n */ ],
michael@0:     unsigned int Pfactor,
michael@0:     int Round
michael@0: );
michael@0: 
michael@0: /* Variant of above using coder spec rather than hardwired 8-bit probs. */
michael@0: 
michael@0: void vp8bc_tree_probs_from_distribution(
michael@0:     int n,                      /* n = size of alphabet */
michael@0:     vp8_token tok               [ /* n */ ],
michael@0:     vp8_tree tree,
michael@0:     vp8_prob probs          [ /* n-1 */ ],
michael@0:     unsigned int branch_ct       [ /* n-1 */ ] [2],
michael@0:     const unsigned int num_events[ /* n */ ],
michael@0:     c_bool_coder_spec *s
michael@0: );
michael@0: 
michael@0: 
michael@0: #endif