source: svn/trunk/newcon3bcm2_21bu/dta/src/dcc/bcmDccBits.h @ 2

/***************************************************************************
 *     Copyright (c) 2002, Broadcom Corporation
 *     All Rights Reserved
 *     Confidential Property of Broadcom Corporation
 *
 *  THIS SOFTWARE MAY ONLY BE USED SUBJECT TO AN EXECUTED SOFTWARE LICENSE
 *  AGREEMENT  BETWEEN THE USER AND BROADCOM.  YOU HAVE NO RIGHT TO USE OR
 *  EXPLOIT THIS MATERIAL EXCEPT SUBJECT TO THE TERMS OF SUCH AN AGREEMENT.
 *
 * $brcm_Workfile: bcmDccBits.h $
 * $brcm_Revision: SanJose_MSTV_Devel\2 $
 * $brcm_Date: 5/13/02 1:14p $
 *
 * Module Description:
 *
 *   This module contains functions useful for extracting bits
 *   from a byte stream.
 *
 * Revision History:
 *
 * $brcm_Log: \SetTop\applications\vbi\Common\bcmDccBits.h $
 * 
 * SanJose_MSTV_Devel\2   5/13/02 1:14p erikg
 * snapshot of dtvcc code  Merge from
 * SanJose_MSTV_Devel_erikg_DTVCC_Int_2002_05_02_1128_00  13-May-
 * 02.11:55:52 \SetTop\applications\vbi Added directory element
 * "DTVCCLib". --- 13-May-02.13:08:38 \SetTop\applications\vbi\Common
 * First version of the Dcc 708 Rendering Libraries --- 13-May-
 * 02.13:08:10 \SetTop\applications\vbi\Common\bcmDccBits.h Added ifdef
 * to ensure included only once.
 * Added extern "C" for __cplusplus --- 13-May-02.13:07:04
 * \SetTop\applications\vbi\MPEGCCTransportLib\source\bcmDccTransportPars
 * e.c NextStartCode() now specifically scans for start codes until it
 * finds
 * 00 00 01 B2. --- 13-May-02.13:08:40
 * \SetTop\applications\vbi\Common@@\main\SanJose_MSTV_Devel\SanJose_MSTV
 * _Devel_erikg_DTVCC_Int_2002_05_02_1128_00\1\bcmDccCBuf.c First version
 * of the Dcc 708 Rendering Libraries --- 13-May-02.13:08:43
 * \SetTop\applications\vbi\Common@@\main\SanJose_MSTV_Devel\SanJose_MSTV
 * _Devel_erikg_DTVCC_Int_2002_05_02_1128_00\1\bcmDccCBuf.h First version
 * of the Dcc 708 Rendering Libraries --- 13-May-02.11:55:59
 * \SetTop\applications\vbi@@\main\SanJose_MSTV_Devel\SanJose_MSTV_Devel_
 * erikg_DTVCC_Int_2002_05_02_1128_00\1\DTVCCLib Added directory element
 * "source". Added directory element "public_inc". ---
 * 
 * SanJose_MSTV_Devel\SanJose_MSTV_Devel_erikg_DTVCC_Int_2002_05_02_1128_00\1   5/13/02 1:8p erikg
 * Added ifdef to ensure included only once.
 * Added extern "C" for __cplusplus
 * 
 * \main\SanJose_MSTV_Devel\1   3/12/02 4:46p erikg
 * Merge from SanJose_MSTV_Devel_erikg_mpegccxport2_2002_03_06_1118_38
 *
 * \main\SanJose_MSTV_Devel_erikg_mpegccxport2_2002_03_06_1118_38\1   3/6/02 11:29a erikg
 * new source files
 * 
 ***************************************************************************/


 
/*************************************************************************
 * 
 * MODULE DETAILS:
 *
 * The functions in this module operate on bits in a byte buffer (array).
 * Each function is given a pointer to the buffer and a byte offset and a
 * bit offset indicating the current position in the buffer.  The byte/bit
 * offsets are either ints or int pointers, depending on whether or not
 * the current position is to be updated.
 * 
 * It is assumed that the first bit to be operated on is in the msb position,
 * that is, 0x80.
 *
 *************************************************************************/


#ifndef BCMDCCBITS_H
#define BCMDCCBITS_H

#ifdef __cplusplus
extern "C" {
#endif


/*************************************************************************
 *
 * FUNCTION:                    getnextbit
 *
 * Inputs:                              
 *                                              pBuf                            - stream buffer
 *                                              pbyteoff                        - current byte offset into pBuf
 *                                              pbitoff                         - bit offset into current byte
 *
 * Outputs:                             
 *                                              pbyteoff                        - current byte offset into pBuf
 *                                              pbitoff                         - bit offset into current byte
 *
 * Returns:                             the requested bit, 0 or 1
 *
 * Description:
 *
 * This function returns the next bit and increments the position.
 *
 *************************************************************************/
unsigned int 
getnextbit(unsigned char * pBuf, int * pbyteoff, int * pbitoff) ;


/*************************************************************************
 *
 * FUNCTION:                    getnextbits
 *
 * Inputs:                              
 *                                              pBuf                            - stream buffer
 *                                              pbyteoff                        - current byte offset into pBuf
 *                                              pbitoff                         - bit offset into current byte
 *                                              numbits                         - number of bits to get (max 32)
 *
 * Outputs:                             
 *                                              pbyteoff                        - current byte offset into pBuf
 *                                              pbitoff                         - bit offset into current byte
 *
 * Returns:                             the requested bits, lsb justified
 *
 * Description:
 *
 * This function returns the requested number of bits and
 * updates the position.
 *
 *************************************************************************/
unsigned int 
getnextbits(unsigned char * pBuf, int * pbyteoff, int * pbitoff, int numbits) ;


/*************************************************************************
 *
 * FUNCTION:                    getnextbits_rev
 *
 * Inputs:                              
 *                                              pBuf                            - stream buffer
 *                                              pbyteoff                        - current byte offset into pBuf
 *                                              pbitoff                         - bit offset into current byte
 *                                              numbits                         - number of bits to get (max 32)
 *
 * Outputs:                             
 *                                              pbyteoff                        - current byte offset into pBuf
 *                                              pbitoff                         - bit offset into current byte
 *
 * Returns:                             the requested bits, bit reversed, lsb justified
 *
 * Description:
 *
 * This function returns the requested number of bits in reverse
 * order and updates the position.
 *
 *************************************************************************/
unsigned int 
getnextbits_rev(unsigned char * pBuf, int * pbyteoff, int * pbitoff, int numbits) ;


/*************************************************************************
 *
 * FUNCTION:                    nextbits
 *
 * Inputs:                              
 *                                              pBuf                            - stream buffer
 *                                              byteoff                         - current byte offset into pBuf
 *                                              bitoff                          - bit offset into current byte
 *                                              numbits                         - number of bits to get (max 32)
 *
 * Outputs:                             
 *                                              <none>
 *
 * Returns:                             the requested bits, lsb justified
 *
 * Description:
 *
 * This function returns the requested number of bits but does
 * not update the position.
 *
 *************************************************************************/
unsigned int 
nextbits(unsigned char * pBuf, int byteoff, int bitoff, int numbits) ;


/*************************************************************************
 *
 * FUNCTION:                    next_start_code
 *
 * Inputs:                              
 *                                              pBuf                            - stream buffer
 *                                              pbyteoff                        - current byte offset into pBuf
 *                                              pbitoff                         - bit offset into current byte
 *                                              numbytes                        - max bytes to scan forward
 *
 * Outputs:                             
 *                                              pbyteoff                        - current byte offset into pBuf
 *                                              pbitoff                         - bit offset into current byte
 *
 * Returns:                             0 for success
 *
 * Description:
 *
 * This function updates the position to the next start code.
 *
 *************************************************************************/
int next_start_code(unsigned char * pBuf, int * pbyteoff, int * pbitoff, int numbytes) ;



#ifdef __cplusplus
}
#endif

#endif /* BCMDCCBITS_H */