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Diffstat (limited to 'libFDK/include/FDK_crc.h')
| -rw-r--r-- | libFDK/include/FDK_crc.h | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/libFDK/include/FDK_crc.h b/libFDK/include/FDK_crc.h new file mode 100644 index 0000000..29ae6c5 --- /dev/null +++ b/libFDK/include/FDK_crc.h @@ -0,0 +1,169 @@ +/******************************** MPEG Audio Encoder ************************** + + (C) copyright Fraunhofer-IIS (1999) + All Rights Reserved + + Please be advised that this software and/or program delivery is + Confidential Information of Fraunhofer and subject to and covered by the + + Fraunhofer IIS Software Evaluation Agreement + between Google Inc. and Fraunhofer + effective and in full force since March 1, 2012. + + You may use this software and/or program only under the terms and + conditions described in the above mentioned Fraunhofer IIS Software + Evaluation Agreement. Any other and/or further use requires a separate agreement. + + + This software and/or program is protected by copyright law and international + treaties. Any reproduction or distribution of this software and/or program, + or any portion of it, may result in severe civil and criminal penalties, and + will be prosecuted to the maximum extent possible under law. + + $Id$ + Initial author: + contents/description: CRC calculation + +******************************************************************************/ + +#ifndef FDK_CRC_H +#define FDK_CRC_H + + + +#include "FDK_bitstream.h" + + +#define MAX_CRC_REGS 3 /*!< Maximal number of overlapping crc region in ADTS channel pair element is two. + Select three independent regions preventively. */ + +/** + * This structure describes single crc region used for crc calculation. + */ +typedef struct +{ + UCHAR isActive; + INT maxBits; + UINT bitBufCntBits; + UINT validBits; + +} CCrcRegData; + +/** + * CRC info structure. + */ +typedef struct +{ + CCrcRegData crcRegData[MAX_CRC_REGS]; /*!< Multiple crc region description. */ + const USHORT *pCrcLookup; /*!< Pointer to lookup table filled in FDK_crcInit(). */ + + USHORT crcPoly; /*!< CRC generator polynom. */ + USHORT crcMask; /*!< CRC mask. */ + USHORT startValue; /*!< CRC start value. */ + UCHAR crcLen; /*!< CRC length. */ + + UINT regStart; /*!< Start region marker for synchronization. */ + UINT regStop; /*!< Stop region marker for synchronization. */ + + USHORT crcValue; /*!< Crc value to be calculated. */ + +} FDK_CRCINFO; + +/** + * CRC info handle. + */ +typedef FDK_CRCINFO* HANDLE_FDK_CRCINFO; + + +/** + * \brief Initialize CRC structure. + * + * The function initializes existing crc info structure with denoted configuration. + * + * \param hCrcInfo Pointer to an outlying allocated crc info structure. + * \param crcPoly Configure crc polynom. + * \param crcStartValue Configure crc start value. + * \param crcLen Configure crc length. + * + * \return none + */ +void FDKcrcInit( + HANDLE_FDK_CRCINFO hCrcInfo, + const UINT crcPoly, + const UINT crcStartValue, + const UINT crcLen + ); + +/** + * \brief Reset CRC info structure. + * + * This function clears all intern states of the crc structure. + * + * \param hCrcInfo Pointer to crc info stucture. + * + * \return none + */ +void FDKcrcReset( + HANDLE_FDK_CRCINFO hCrcInfo + ); + + +/** + * \brief Start CRC region with maximum number of bits. + * + * This function marks position in bitstream to be used as start point for crc calculation. + * Bitstream range for crc calculation can be limited or kept dynamic depending on mBits parameter. + * The crc region has to be terminated with FDKcrcEndReg() in each case. + * + * \param hCrcInfo Pointer to crc info stucture. + * \param hBs Pointer to current bit buffer structure. + * \param mBits Number of bits in crc region to be calculated. + * - mBits > 0: Zero padding will be used for CRC calculation, if there + * are less than mBits bits available. + * - mBits < 0: No zero padding is done. + * - mBits = 0: The number of bits used in crc calculation is dynamically, + * depending on bitstream position between FDKcrcStartReg() and + * FDKcrcEndReg() call. + * + * \return ID for the created region, -1 in case of an error + */ +INT FDKcrcStartReg( + HANDLE_FDK_CRCINFO hCrcInfo, + const HANDLE_FDK_BITSTREAM hBs, + const INT mBits + ); + + +/** + * \brief Ends CRC region. + * + * This function terminates crc region specified with FDKcrcStartReg(). The number of bits in crc region depends + * on mBits parameter of FDKcrcStartReg(). + * This function calculates and updates crc in info structure. + * + * \param hCrcInfo Pointer to crc info stucture. + * \param hBs Pointer to current bit buffer structure. + * \param reg Crc region ID created in FDKcrcStartReg(). + * + * \return 0 on success + */ +INT FDKcrcEndReg( + HANDLE_FDK_CRCINFO hCrcInfo, + const HANDLE_FDK_BITSTREAM hBs, + const INT reg + ); + + +/** + * \brief This function returns crc value from info struct. + * + * \param hCrcInfo Pointer to crc info stucture. + * + * \return CRC value masked with crc length. + */ +USHORT FDKcrcGetCRC( + const HANDLE_FDK_CRCINFO hCrcInfo + ); + + +#endif /* FDK_CRC_H */ |