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Diffstat (limited to 'media/libstagefright/codecs/aacdec/sbr_crc_check.cpp')
| -rw-r--r-- | media/libstagefright/codecs/aacdec/sbr_crc_check.cpp | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/aacdec/sbr_crc_check.cpp b/media/libstagefright/codecs/aacdec/sbr_crc_check.cpp new file mode 100644 index 0000000..3bb4398 --- /dev/null +++ b/media/libstagefright/codecs/aacdec/sbr_crc_check.cpp @@ -0,0 +1,191 @@ +/* ------------------------------------------------------------------ + * 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 + + |