| /* ------------------------------------------------------------------ |
| * Copyright (C) 1998-2009 PacketVideo |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either |
| * express or implied. |
| * See the License for the specific language governing permissions |
| * and limitations under the License. |
| * ------------------------------------------------------------------- |
| */ |
| /* |
| |
| Filename: sbr_crc_check.c |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| |
| Who: Date: MM/DD/YYYY |
| Description: |
| |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| SC 29 Software Copyright Licencing Disclaimer: |
| |
| This software module was originally developed by |
| Coding Technologies |
| |
| and edited by |
| - |
| |
| in the course of development of the ISO/IEC 13818-7 and ISO/IEC 14496-3 |
| standards for reference purposes and its performance may not have been |
| optimized. This software module is an implementation of one or more tools as |
| specified by the ISO/IEC 13818-7 and ISO/IEC 14496-3 standards. |
| ISO/IEC gives users free license to this software module or modifications |
| thereof for use in products claiming conformance to audiovisual and |
| image-coding related ITU Recommendations and/or ISO/IEC International |
| Standards. ISO/IEC gives users the same free license to this software module or |
| modifications thereof for research purposes and further ISO/IEC standardisation. |
| Those intending to use this software module in products are advised that its |
| use may infringe existing patents. ISO/IEC have no liability for use of this |
| software module or modifications thereof. Copyright is not released for |
| products that do not conform to audiovisual and image-coding related ITU |
| Recommendations and/or ISO/IEC International Standards. |
| The original developer retains full right to modify and use the code for its |
| own purpose, assign or donate the code to a third party and to inhibit third |
| parties from using the code for products that do not conform to audiovisual and |
| image-coding related ITU Recommendations and/or ISO/IEC International Standards. |
| This copyright notice must be included in all copies or derivative works. |
| Copyright (c) ISO/IEC 2002. |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| |
| #ifdef AAC_PLUS |
| |
| |
| #include "sbr_crc_check.h" |
| #include "s_crc_buffer.h" |
| #include "buf_getbits.h" |
| #include "sbr_constants.h" |
| #include "check_crc.h" |
| |
| |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; MACROS |
| ; Define module specific macros here |
| ----------------------------------------------------------------------------*/ |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; DEFINES |
| ; Include all pre-processor statements here. Include conditional |
| ; compile variables also. |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL FUNCTION DEFINITIONS |
| ; Function Prototype declaration |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; LOCAL STORE/BUFFER/POINTER DEFINITIONS |
| ; Variable declaration - defined here and used outside this module |
| ----------------------------------------------------------------------------*/ |
| |
| const unsigned short MAXCRCSTEP = 16; |
| |
| /*---------------------------------------------------------------------------- |
| ; EXTERNAL FUNCTION REFERENCES |
| ; Declare functions defined elsewhere and referenced in this module |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES |
| ; Declare variables used in this module but defined elsewhere |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; FUNCTION CODE |
| ----------------------------------------------------------------------------*/ |
| |
| Int32 sbr_crc_check(BIT_BUFFER * hBitBuf, UInt32 NrBits) |
| { |
| Int32 crcResult = 1; |
| BIT_BUFFER BitBufferCRC; |
| UInt32 NrCrcBits; |
| |
| UInt32 crcCheckSum; |
| |
| Int32 i; |
| CRC_BUFFER CrcBuf; |
| UInt32 bValue; |
| Int32 CrcStep; |
| Int32 CrcNrBitsRest; |
| |
| crcCheckSum = buf_getbits(hBitBuf, SI_SBR_CRC_BITS); |
| |
| |
| /* |
| * Copy Bit buffer State |
| */ |
| |
| BitBufferCRC.char_ptr = hBitBuf->char_ptr; |
| BitBufferCRC.buffer_word = hBitBuf->buffer_word; |
| BitBufferCRC.buffered_bits = hBitBuf->buffered_bits; |
| BitBufferCRC.nrBitsRead = hBitBuf->nrBitsRead; |
| BitBufferCRC.bufferLen = hBitBuf->bufferLen; |
| |
| |
| NrCrcBits = min(NrBits, BitBufferCRC.bufferLen - BitBufferCRC.nrBitsRead); |
| |
| |
| CrcStep = NrCrcBits / MAXCRCSTEP; |
| CrcNrBitsRest = (NrCrcBits - CrcStep * MAXCRCSTEP); |
| |
| CrcBuf.crcState = CRCSTART; |
| CrcBuf.crcMask = CRCMASK; |
| CrcBuf.crcPoly = CRCPOLY; |
| |
| for (i = 0; i < CrcStep; i++) |
| { |
| bValue = buf_getbits(&BitBufferCRC, MAXCRCSTEP); |
| check_crc(&CrcBuf, bValue, MAXCRCSTEP); |
| } |
| |
| bValue = buf_getbits(&BitBufferCRC, CrcNrBitsRest); |
| check_crc(&CrcBuf, bValue, CrcNrBitsRest); |
| |
| if ((UInt32)(CrcBuf.crcState & CRCRANGE) != crcCheckSum) |
| { |
| crcResult = 0; |
| } |
| |
| return (crcResult); |
| } |
| |
| #endif |
| |
| |