1/* 2 * Copyright (c) 2010 The WebM project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 12/**************************************************************************** 13* 14* Module Title : boolhuff.h 15* 16* Description : Bool Coder header file. 17* 18****************************************************************************/ 19#ifndef VP8_ENCODER_BOOLHUFF_H_ 20#define VP8_ENCODER_BOOLHUFF_H_ 21 22#include "vpx_ports/mem.h" 23#include "vpx/internal/vpx_codec_internal.h" 24 25#ifdef __cplusplus 26extern "C" { 27#endif 28 29typedef struct 30{ 31 unsigned int lowvalue; 32 unsigned int range; 33 int count; 34 unsigned int pos; 35 unsigned char *buffer; 36 unsigned char *buffer_end; 37 struct vpx_internal_error_info *error; 38} BOOL_CODER; 39 40extern void vp8_start_encode(BOOL_CODER *bc, unsigned char *buffer, unsigned char *buffer_end); 41 42extern void vp8_encode_value(BOOL_CODER *br, int data, int bits); 43extern void vp8_stop_encode(BOOL_CODER *bc); 44extern const unsigned int vp8_prob_cost[256]; 45 46 47DECLARE_ALIGNED(16, extern const unsigned char, vp8_norm[256]); 48 49static int validate_buffer(const unsigned char *start, 50 size_t len, 51 const unsigned char *end, 52 struct vpx_internal_error_info *error) 53{ 54 if (start + len > start && start + len < end) 55 return 1; 56 else 57 vpx_internal_error(error, VPX_CODEC_CORRUPT_FRAME, 58 "Truncated packet or corrupt partition "); 59 60 return 0; 61} 62static void vp8_encode_bool(BOOL_CODER *br, int bit, int probability) 63{ 64 unsigned int split; 65 int count = br->count; 66 unsigned int range = br->range; 67 unsigned int lowvalue = br->lowvalue; 68 register unsigned int shift; 69 70#ifdef VP8_ENTROPY_STATS 71#if defined(SECTIONBITS_OUTPUT) 72 73 if (bit) 74 Sectionbits[active_section] += vp8_prob_cost[255-probability]; 75 else 76 Sectionbits[active_section] += vp8_prob_cost[probability]; 77 78#endif 79#endif 80 81 split = 1 + (((range - 1) * probability) >> 8); 82 83 range = split; 84 85 if (bit) 86 { 87 lowvalue += split; 88 range = br->range - split; 89 } 90 91 shift = vp8_norm[range]; 92 93 range <<= shift; 94 count += shift; 95 96 if (count >= 0) 97 { 98 int offset = shift - count; 99 100 if ((lowvalue << (offset - 1)) & 0x80000000) 101 { 102 int x = br->pos - 1; 103 104 while (x >= 0 && br->buffer[x] == 0xff) 105 { 106 br->buffer[x] = (unsigned char)0; 107 x--; 108 } 109 110 br->buffer[x] += 1; 111 } 112 113 validate_buffer(br->buffer + br->pos, 1, br->buffer_end, br->error); 114 br->buffer[br->pos++] = (lowvalue >> (24 - offset)); 115 116 lowvalue <<= offset; 117 shift = count; 118 lowvalue &= 0xffffff; 119 count -= 8 ; 120 } 121 122 lowvalue <<= shift; 123 br->count = count; 124 br->lowvalue = lowvalue; 125 br->range = range; 126} 127 128#ifdef __cplusplus 129} // extern "C" 130#endif 131 132#endif // VP8_ENCODER_BOOLHUFF_H_ 133