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Diffstat (limited to 'libSBRdec/src/sbr_crc.cpp')
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diff --git a/libSBRdec/src/sbr_crc.cpp b/libSBRdec/src/sbr_crc.cpp new file mode 100644 index 0000000..760bd1f --- /dev/null +++ b/libSBRdec/src/sbr_crc.cpp @@ -0,0 +1,183 @@ + +/* ----------------------------------------------------------------------------------------------------------- +Software License for The Fraunhofer FDK AAC Codec Library for Android + +© Copyright 1995 - 2012 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. + All rights reserved. + + 1. INTRODUCTION +The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements +the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio. +This FDK AAC Codec software is intended to be used on a wide variety of Android devices. + +AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual +audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by +independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part +of the MPEG specifications. + +Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer) +may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners +individually for the purpose of encoding or decoding bit streams in products that are compliant with +the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license +these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec +software may already be covered under those patent licenses when it is used for those licensed purposes only. + +Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality, +are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional +applications information and documentation. + +2. COPYRIGHT LICENSE + +Redistribution and use in source and binary forms, with or without modification, are permitted without +payment of copyright license fees provided that you satisfy the following conditions: + +You must retain the complete text of this software license in redistributions of the FDK AAC Codec or +your modifications thereto in source code form. + +You must retain the complete text of this software license in the documentation and/or other materials +provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form. +You must make available free of charge copies of the complete source code of the FDK AAC Codec and your +modifications thereto to recipients of copies in binary form. + +The name of Fraunhofer may not be used to endorse or promote products derived from this library without +prior written permission. + +You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec +software or your modifications thereto. + +Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software +and the date of any change. For modified versions of the FDK AAC Codec, the term +"Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term +"Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android." + +3. NO PATENT LICENSE + +NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer, +ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with +respect to this software. + +You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized +by appropriate patent licenses. + +4. DISCLAIMER + +This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors +"AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties +of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR +CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages, +including but not limited to procurement of substitute goods or services; loss of use, data, or profits, +or business interruption, however caused and on any theory of liability, whether in contract, strict +liability, or tort (including negligence), arising in any way out of the use of this software, even if +advised of the possibility of such damage. + +5. CONTACT INFORMATION + +Fraunhofer Institute for Integrated Circuits IIS +Attention: Audio and Multimedia Departments - FDK AAC LL +Am Wolfsmantel 33 +91058 Erlangen, Germany + +www.iis.fraunhofer.de/amm +amm-info@iis.fraunhofer.de +----------------------------------------------------------------------------------------------------------- */ + +/*! + \file + \brief CRC check coutines +*/ + +#include "sbr_crc.h" + +#include "FDK_bitstream.h" +#include "transcendent.h" + +#define MAXCRCSTEP 16 +#define MAXCRCSTEP_LD 4 + +/*! + \brief crc calculation +*/ +static ULONG +calcCRC (HANDLE_CRC hCrcBuf, ULONG bValue, int nBits) +{ + int i; + ULONG bMask = (1UL << (nBits - 1)); + + for (i = 0; i < nBits; i++, bMask >>= 1) { + USHORT flag = (hCrcBuf->crcState & hCrcBuf->crcMask) ? 1 : 0; + USHORT flag1 = (bMask & bValue) ? 1 : 0; + + flag ^= flag1; + hCrcBuf->crcState <<= 1; + if (flag) + hCrcBuf->crcState ^= hCrcBuf->crcPoly; + } + + return (hCrcBuf->crcState); +} + + +/*! + \brief crc +*/ +static int +getCrc (HANDLE_FDK_BITSTREAM hBs, ULONG NrBits) +{ + int i; + CRC_BUFFER CrcBuf; + + CrcBuf.crcState = SBR_CRC_START; + CrcBuf.crcPoly = SBR_CRC_POLY; + CrcBuf.crcMask = SBR_CRC_MASK; + + int CrcStep = NrBits>>MAXCRCSTEP_LD; + + int CrcNrBitsRest = (NrBits - CrcStep * MAXCRCSTEP); + ULONG bValue; + + for (i = 0; i < CrcStep; i++) { + bValue = FDKreadBits (hBs, MAXCRCSTEP); + calcCRC (&CrcBuf, bValue, MAXCRCSTEP); + } + + bValue = FDKreadBits (hBs, CrcNrBitsRest); + calcCRC (&CrcBuf, bValue, CrcNrBitsRest); + + return (CrcBuf.crcState & SBR_CRC_RANGE); + +} + + +/*! + \brief crc interface + \return 1: CRC OK, 0: CRC check failure +*/ +int +SbrCrcCheck (HANDLE_FDK_BITSTREAM hBs, /*!< handle to bit-buffer */ + LONG NrBits) /*!< max. CRC length */ +{ + int crcResult = 1; + ULONG NrCrcBits; + ULONG crcCheckResult; + LONG NrBitsAvailable; + ULONG crcCheckSum; + + crcCheckSum = FDKreadBits (hBs, 10); + + NrBitsAvailable = FDKgetValidBits(hBs); + if (NrBitsAvailable <= 0){ + return 0; + } + + NrCrcBits = fixMin ((INT)NrBits, (INT)NrBitsAvailable); + + crcCheckResult = getCrc (hBs, NrCrcBits); + FDKpushBack(hBs, (NrBitsAvailable - FDKgetValidBits(hBs)) ); + + + if (crcCheckResult != crcCheckSum) { + crcResult = 0; + } + + return (crcResult); +} |