1 /* ------------------------------------------------------------------ 2 * Copyright (C) 1998-2009 PacketVideo 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either 13 * express or implied. 14 * See the License for the specific language governing permissions 15 * and limitations under the License. 16 * ------------------------------------------------------------------- 17 */ 18 /* 19 20 Filename: sbr_decode_huff_cw.c 21 22 ------------------------------------------------------------------------------ 23 REVISION HISTORY 24 25 26 Who: Date: MM/DD/YYYY 27 Description: 28 29 ------------------------------------------------------------------------------ 30 INPUT AND OUTPUT DEFINITIONS 31 32 SbrHuffman h, pointer to huffman codebook table 33 BIT_BUFFER * hBitBuf pointer to Bitbuffer 34 35 return decoded value 36 ------------------------------------------------------------------------------ 37 FUNCTION DESCRIPTION 38 39 Decodes one huffman code word 40 41 Reads bits from the bitstream until a valid codeword is found. 42 The table entries are interpreted either as index to the next entry 43 or - if negative - as the codeword. 44 45 ------------------------------------------------------------------------------ 46 REQUIREMENTS 47 48 49 ------------------------------------------------------------------------------ 50 REFERENCES 51 52 SC 29 Software Copyright Licencing Disclaimer: 53 54 This software module was originally developed by 55 Coding Technologies 56 57 and edited by 58 - 59 60 in the course of development of the ISO/IEC 13818-7 and ISO/IEC 14496-3 61 standards for reference purposes and its performance may not have been 62 optimized. This software module is an implementation of one or more tools as 63 specified by the ISO/IEC 13818-7 and ISO/IEC 14496-3 standards. 64 ISO/IEC gives users free license to this software module or modifications 65 thereof for use in products claiming conformance to audiovisual and 66 image-coding related ITU Recommendations and/or ISO/IEC International 67 Standards. ISO/IEC gives users the same free license to this software module or 68 modifications thereof for research purposes and further ISO/IEC standardisation. 69 Those intending to use this software module in products are advised that its 70 use may infringe existing patents. ISO/IEC have no liability for use of this 71 software module or modifications thereof. Copyright is not released for 72 products that do not conform to audiovisual and image-coding related ITU 73 Recommendations and/or ISO/IEC International Standards. 74 The original developer retains full right to modify and use the code for its 75 own purpose, assign or donate the code to a third party and to inhibit third 76 parties from using the code for products that do not conform to audiovisual and 77 image-coding related ITU Recommendations and/or ISO/IEC International Standards. 78 This copyright notice must be included in all copies or derivative works. 79 Copyright (c) ISO/IEC 2002. 80 81 ------------------------------------------------------------------------------ 82 PSEUDO-CODE 83 84 ------------------------------------------------------------------------------ 85 */ 86 87 88 /*---------------------------------------------------------------------------- 89 ; INCLUDES 90 ----------------------------------------------------------------------------*/ 91 92 #ifdef AAC_PLUS 93 94 95 #include "sbr_decode_huff_cw.h" 96 #include "buf_getbits.h" 97 98 /*---------------------------------------------------------------------------- 99 ; MACROS 100 ; Define module specific macros here 101 ----------------------------------------------------------------------------*/ 102 103 104 /*---------------------------------------------------------------------------- 105 ; DEFINES 106 ; Include all pre-processor statements here. Include conditional 107 ; compile variables also. 108 ----------------------------------------------------------------------------*/ 109 110 /*---------------------------------------------------------------------------- 111 ; LOCAL FUNCTION DEFINITIONS 112 ; Function Prototype declaration 113 ----------------------------------------------------------------------------*/ 114 115 /*---------------------------------------------------------------------------- 116 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS 117 ; Variable declaration - defined here and used outside this module 118 ----------------------------------------------------------------------------*/ 119 120 /*---------------------------------------------------------------------------- 121 ; EXTERNAL FUNCTION REFERENCES 122 ; Declare functions defined elsewhere and referenced in this module 123 ----------------------------------------------------------------------------*/ 124 125 /*---------------------------------------------------------------------------- 126 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES 127 ; Declare variables used in this module but defined elsewhere 128 ----------------------------------------------------------------------------*/ 129 130 /*---------------------------------------------------------------------------- 131 ; FUNCTION CODE 132 ----------------------------------------------------------------------------*/ 133 134 Int32 sbr_decode_huff_cw(SbrHuffman h, 135 BIT_BUFFER * hBitBuf) 136 { 137 Int32 bits; 138 Char index = 0; 139 140 while (index >= 0) 141 { 142 bits = buf_get_1bit(hBitBuf); 143 index = h[index][bits]; 144 } 145 146 return((Int32)index + 64); /* Add offset */ 147 } 148 149 #endif 150
