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 #include "dboolhuff.h" 13 #include "vpx_ports/mem.h" 14 #include "vpx_mem/vpx_mem.h" 15 16 DECLARE_ALIGNED(16, const unsigned char, vp8dx_bitreader_norm[256]) = 17 { 18 0, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 19 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 20 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 21 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 22 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 23 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 24 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 25 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 26 }; 27 28 29 int vp8dx_start_decode_c(BOOL_DECODER *br, const unsigned char *source, 30 unsigned int source_sz) 31 { 32 br->user_buffer_end = source+source_sz; 33 br->user_buffer = source; 34 br->value = 0; 35 br->count = -8; 36 br->range = 255; 37 38 if (source_sz && !source) 39 return 1; 40 41 /* Populate the buffer */ 42 vp8dx_bool_decoder_fill_c(br); 43 44 return 0; 45 } 46 47 48 void vp8dx_bool_decoder_fill_c(BOOL_DECODER *br) 49 { 50 const unsigned char *bufptr; 51 const unsigned char *bufend; 52 VP8_BD_VALUE value; 53 int count; 54 bufend = br->user_buffer_end; 55 bufptr = br->user_buffer; 56 value = br->value; 57 count = br->count; 58 59 VP8DX_BOOL_DECODER_FILL(count, value, bufptr, bufend); 60 61 br->user_buffer = bufptr; 62 br->value = value; 63 br->count = count; 64 } 65 66 #if 0 67 /* 68 * Until optimized versions of these functions are available, we 69 * keep the implementation in the header to allow inlining. 70 * 71 * The RTCD-style invocations are still in place so this can 72 * be switched by just uncommenting these functions here and 73 * the DBOOLHUFF_INVOKE calls in the header. 74 */ 75 int vp8dx_decode_bool_c(BOOL_DECODER *br, int probability) 76 { 77 unsigned int bit=0; 78 VP8_BD_VALUE value; 79 unsigned int split; 80 VP8_BD_VALUE bigsplit; 81 int count; 82 unsigned int range; 83 84 value = br->value; 85 count = br->count; 86 range = br->range; 87 88 split = 1 + (((range-1) * probability) >> 8); 89 bigsplit = (VP8_BD_VALUE)split << (VP8_BD_VALUE_SIZE - 8); 90 91 range = split; 92 if(value >= bigsplit) 93 { 94 range = br->range-split; 95 value = value-bigsplit; 96 bit = 1; 97 } 98 99 /*if(range>=0x80) 100 { 101 br->value = value; 102 br->range = range; 103 return bit; 104 }*/ 105 106 { 107 register unsigned int shift = vp8dx_bitreader_norm[range]; 108 range <<= shift; 109 value <<= shift; 110 count -= shift; 111 } 112 br->value = value; 113 br->count = count; 114 br->range = range; 115 if (count < 0) 116 vp8dx_bool_decoder_fill_c(br); 117 return bit; 118 } 119 120 int vp8dx_decode_value_c(BOOL_DECODER *br, int bits) 121 { 122 int z = 0; 123 int bit; 124 for ( bit=bits-1; bit>=0; bit-- ) 125 { 126 z |= (vp8dx_decode_bool(br, 0x80)<<bit); 127 } 128 return z; 129 } 130 #endif 131
