bitbuffer.h

Nokia H.264/AVC Encoder/Decoder Usage Manual

/*
COPYRIGHT, LICENSE AND WARRANTY INFORMATION

This software module has been originally developed by Nokia Corporation. 

Provided that a person, entity or a company willing to use the Software 
(hereinafter Licensee) comply with all the terms and conditions of this 
Statement and subject to the limitations set forth in this Statement Nokia 
grants to such Licensee a non-exclusive, sub-licensable, worldwide, 
limited license under copyrights owned by Nokia to use the Software for 
the sole purpose of creating, manufacturing, selling, marketing, or  
distributing (including the right to make modifications to the Software) 
a fully compliant decoder implementation (hereinafter "Decoder") of 
ITU-T Recommendation H.264 / ISO/IEC International Standard 14496-10 and 
an encoder implementation producing output that is decodable with the 
Decoder.

Nokia retains the ownership of copyrights to the Software. There is no 
patent nor other intellectual property right of Nokia licensed under this 
Statement (except the copyright license above). Licensee hereby assumes 
sole responsibility to secure any other intellectual property rights 
needed, if any. For example, if patent licenses  are required, it is 
their responsibility to acquire the license before utilizing the Software.

The license by Nokia is subject to that the Licensee grants to Nokia the 
non-exclusive, worldwide, royalty-free, perpetual and irrevocable 
covenant that the Licensee(s) shall not bring a suit before any court or 
administrative agency or otherwise assert a claim for infringement under 
the Licensee intellectual property rights that, but for a license, would 
be infringed by the Software against  
   (a)  Nokia or Nokia's Affiliate; or  
   (b)  other recipient of a license and covenant not to sue with respect 
        to the Software from Nokia; or 
   (c)  contractor, customer or distributor of a party listed above in a 
        or b,  
which suit or claim is related to the Software or use thereof.

The Licensee(s) further agrees to grant a reciprocal license to Nokia 
(as granted by Nokia to the Licensee(s) on the modifications made by 
Licensee(s) to the Software. 

THE SOFTWARE IS PROVIDED "AS IS" AND THE ORIGINAL DEVELOPER DISCLAIMS 
ANY AND ALL WARRANTIES WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING 
BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS 
FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. THOSE INTENDING TO USE 
THE SOFTWARE ARE EXPRESSLY ADVISED THAT ITS USE MAY INFRINGE EXISTING 
PATENTS AND BE SUBJECT TO ROYALTY PAYMENTS TO PATENT OWNERS. ANYONE 
USING THE SOFTWARE ON THE BASIS OF THIS LICENSE AGREES TO OBTAIN THE 
NECESSARY PERMISSIONS FROM ANY AND ALL APPLICABLE PATENT OWNERS FOR SUCH 
USE.

IN NO EVENT SHALL THE ORIGINAL DEVELOPER BE LIABLE FOR ANY CLAIM, 
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT 
OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE 
OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

This copyright, license and warranty information notice must be retained 
in all copies and derivative works of the Software or substantial 
portions thereof.
*/



#ifndef _BITBUFFER_H_
#define _BITBUFFER_H_


#include "globals.h"


#define BIB_ERR_BIT_ERROR          -4
#define BIB_INCORRECT_TRAILING_BIT -3
#define BIB_ERR_NO_BITS            -2
#define BIB_ERROR                  -1
#define BIB_OK                      0


typedef struct _bitbuffer_s 
{
  u_int8 *data;     /* point to the bit buffer. The physical buffer is allocated by the main module */
  int dataLen;
  int bytePos;
  int bitpos;
  int32 currentBits;
  int errorStatus;
} bitbuffer_s;


#define bibRaiseError(bitbuf, error) ((bitbuf)->errorStatus = (error))

#define bibGetStatus(bitbuf) (bitbuf)->errorStatus


bitbuffer_s *bibOpen();

int bibInit(bitbuffer_s *bitbuf, u_int8 *streamBytes, int length);

void bibClose(bitbuffer_s *bitbuf);

int bibGetBitFunc(bitbuffer_s *bitbuf);

int32 bibGetBitsFunc(bitbuffer_s *bitbuf, int n);

int32 bibShowBitsFunc(bitbuffer_s *bitbuf, int n);

int bibSkipBitsFunc(bitbuffer_s *bitbuf, int n);

int bibGetByte(bitbuffer_s *bitbuf, int *byteRet);

int bibByteAlign(bitbuffer_s *bitbuf);

int bibSkipTrailingBits(bitbuffer_s *bitbuf);

int bibMoreRbspData(bitbuffer_s *bitbuf);

int32 bibGetNumRemainingBits(bitbuffer_s *bitbuf);


/*
 *
 * bibGetBit
 *
 * Parameters:
 *      bitbuf                Bitbuffer object
 *      bit                   Return pointer for bit
 *
 * Function:
 *      Get next bit from bitbuffer.
 *
 * Returns:
 *      -
 *
 */
#define bibGetBit(bitbuf, bit) \
  if ((bitbuf)->bitpos <= 0) { \
    if ((bitbuf)->bytePos < (bitbuf)->dataLen) { \
      (bitbuf)->currentBits = (bitbuf)->data[(bitbuf)->bytePos++]; \
      (bitbuf)->bitpos = 7; \
      *(bit) = ((bitbuf)->currentBits >> (bitbuf)->bitpos) & 1; \
    } \
    else { \
      (bitbuf)->errorStatus = BIB_ERR_NO_BITS; \
      *(bit) = 0; \
    } \
  } \
  else { \
    (bitbuf)->bitpos--; \
    *(bit) = ((bitbuf)->currentBits >> (bitbuf)->bitpos) & 1; \
  }


/*
 *
 * bibGetBits
 *
 * Parameters:
 *      bitbuf                Bitbuffer object
 *      n                     Number of bits requested
 *      bits                  Return pointer for bits
 *
 * Function:
 *      Get next n bits from bitbuffer. If bitbuffer is low on bits,
 *      call bibGetBitsFunc to get more.
 *
 *      NOTE: maximum of 24 bits can be fetched
 *
 * Returns:
 *      -
 *
 */
#define bibGetBits(bitbuf, n, bits) \
  if ((n) > (bitbuf)->bitpos) { \
    if ((bitbuf)->bytePos+2 >= (bitbuf)->dataLen) \
      *(bits) = bibGetBitsFunc(bitbuf, n); \
    else { \
      do { \
        (bitbuf)->currentBits = ((bitbuf)->currentBits << 8) | (bitbuf)->data[(bitbuf)->bytePos++]; \
        (bitbuf)->bitpos += 8; \
      } while ((n) > (bitbuf)->bitpos); \
      (bitbuf)->bitpos -= (n); \
      *(bits) = ((bitbuf)->currentBits >> (bitbuf)->bitpos) & ~(((u_int32)-1)<<(n)); \
    } \
  } \
  else { \
    (bitbuf)->bitpos -= (n); \
    *(bits) = ((bitbuf)->currentBits >> (bitbuf)->bitpos) & ~(((u_int32)-1)<<(n)); \
  }


/*
 *
 * bibGetMax16bits
 *
 * Parameters:
 *      bitbuf                Bitbuffer object
 *      n                     Number of bits requested
 *      bits                  Return pointer for bits
 *
 * Function:
 *      Get next n bits from bitbuffer. If bitbuffer is low on bits,
 *      call bibGetBitsFunc to get more.
 *
 *      NOTE: maximum of 16 bits can be fetched
 *
 * Returns:
 *      -
 *
 */
#define bibGetMax16bits(bitbuf, n, bits) \
  if ((n) > (bitbuf)->bitpos) { \
    if ((bitbuf)->bytePos+1 >= (bitbuf)->dataLen) \
      *(bits) = bibGetBitsFunc(bitbuf, n); \
    else { \
      (bitbuf)->currentBits = ((bitbuf)->currentBits << 8) | (bitbuf)->data[(bitbuf)->bytePos++]; \
      (bitbuf)->currentBits = ((bitbuf)->currentBits << 8) | (bitbuf)->data[(bitbuf)->bytePos++]; \
      (bitbuf)->bitpos += 16; \
      (bitbuf)->bitpos -= (n); \
      *(bits) = ((bitbuf)->currentBits >> (bitbuf)->bitpos) & ~(((u_int32)-1)<<(n)); \
    } \
  } \
  else { \
    (bitbuf)->bitpos -= (n); \
    *(bits) = ((bitbuf)->currentBits >> (bitbuf)->bitpos) & ~(((u_int32)-1)<<(n)); \
  }


/*
 *
 * bibGetMax8bits
 *
 * Parameters:
 *      bitbuf                Bitbuffer object
 *      n                     Number of bits requested
 *      bits                  Return pointer for bits
 *
 * Function:
 *      Get next n bits from bitbuffer. If bitbuffer is low on bits,
 *      call bibGetBitsFunc to get more.
 *
 *      NOTE: maximum of 8 bits can be fetched
 *
 * Returns:
 *      -
 *
 */
#define bibGetMax8bits(bitbuf, n, bits) \
  if ((n) > (bitbuf)->bitpos) { \
    if ((bitbuf)->bytePos >= (bitbuf)->dataLen) \
      *(bits) = bibGetBitsFunc(bitbuf, n); \
    else { \
      (bitbuf)->currentBits = ((bitbuf)->currentBits << 8) | (bitbuf)->data[(bitbuf)->bytePos++]; \
      (bitbuf)->bitpos += 8; \
      (bitbuf)->bitpos -= (n); \
      *(bits) = ((bitbuf)->currentBits >> (bitbuf)->bitpos) & ~(((u_int32)-1)<<(n)); \
    } \
  } \
  else { \
    (bitbuf)->bitpos -= (n); \
    *(bits) = ((bitbuf)->currentBits >> (bitbuf)->bitpos) & ~(((u_int32)-1)<<(n)); \
  }


/*
 *
 * bibShowBits
 *
 * Parameters:
 *      bitbuf                Bitbuffer object
 *      n                     Number of bits requested
 *      bits                  Return pointer for bits
 *
 * Function:
 *      Get next n bits from bitbuffer without advancing bitbuffer pointer.
 *      If bitbuffer is low on bits, call bibShowBitsFunc to get more.
 *
 *      NOTE: maximum of 24 bits can be fetched
 *
 * Returns:
 *      -
 *
 */
#define bibShowBits(bitbuf, n, bits) \
  if ((n) > (bitbuf)->bitpos) { \
    if ((bitbuf)->bytePos+2 >= (bitbuf)->dataLen) \
      *(bits) = bibShowBitsFunc(bitbuf, n); \
    else { \
      do { \
        (bitbuf)->currentBits = ((bitbuf)->currentBits << 8) | (bitbuf)->data[(bitbuf)->bytePos++]; \
        (bitbuf)->bitpos += 8; \
      } while ((n) > (bitbuf)->bitpos); \
      *(bits) = ((bitbuf)->currentBits >> ((bitbuf)->bitpos-(n))) & ~(((u_int32)-1)<<(n)); \
    } \
  } \
  else \
    *(bits) = ((bitbuf)->currentBits >> ((bitbuf)->bitpos-(n))) & ~(((u_int32)-1)<<(n));


/*
 *
 * bibShowMax16bits
 *
 * Parameters:
 *      bitbuf                Bitbuffer object
 *      n                     Number of bits requested
 *      bits                  Return pointer for bits
 *
 * Function:
 *      Get next n bits from bitbuffer without advancing bitbuffer pointer.
 *      If bitbuffer is low on bits, call bibShowBitsFunc to get more.
 *
 *      NOTE: maximum of 16 bits can be fetched
 *
 * Returns:
 *      -
 *
 */
#define bibShowMax16bits(bitbuf, n, bits) \
  if ((n) > (bitbuf)->bitpos) { \
    if ((bitbuf)->bytePos+1 >= (bitbuf)->dataLen) \
      *(bits) = bibShowBitsFunc(bitbuf, n); \
    else { \
      (bitbuf)->currentBits = ((bitbuf)->currentBits << 8) | (bitbuf)->data[(bitbuf)->bytePos++]; \
      (bitbuf)->currentBits = ((bitbuf)->currentBits << 8) | (bitbuf)->data[(bitbuf)->bytePos++]; \
      (bitbuf)->bitpos += 16; \
      *(bits) = ((bitbuf)->currentBits >> ((bitbuf)->bitpos-(n))) & ~(((u_int32)-1)<<(n)); \
    } \
  } \
  else \
    *(bits) = ((bitbuf)->currentBits >> ((bitbuf)->bitpos-(n))) & ~(((u_int32)-1)<<(n));


/*
 *
 * bibShowMax8bits
 *
 * Parameters:
 *      bitbuf                Bitbuffer object
 *      n                     Number of bits requested
 *      bits                  Return pointer for bits
 *
 * Function:
 *      Get next n bits from bitbuffer without advancing bitbuffer pointer.
 *      If bitbuffer is low on bits, call bibShowBitsFunc to get more.
 *
 *      NOTE: maximum of 8 bits can be fetched
 *
 * Returns:
 *      -
 *
 */
#define bibShowMax8bits(bitbuf, n, bits) \
  if ((n) > (bitbuf)->bitpos) { \
    if ((bitbuf)->bytePos >= (bitbuf)->dataLen) \
      *(bits) = bibShowBitsFunc(bitbuf, n); \
    else { \
      (bitbuf)->currentBits = ((bitbuf)->currentBits << 8) | (bitbuf)->data[(bitbuf)->bytePos++]; \
      (bitbuf)->bitpos += 8; \
      *(bits) = ((bitbuf)->currentBits >> ((bitbuf)->bitpos-(n))) & ~(((u_int32)-1)<<(n)); \
    } \
  } \
  else \
    *(bits) = ((bitbuf)->currentBits >> ((bitbuf)->bitpos-(n))) & ~(((u_int32)-1)<<(n));


/*
 *
 * bibSkipBits
 *
 * Parameters:
 *      bitbuf                Bitbuffer object
 *      n                     Number of bits to be skipped
 *
 * Function:
 *      Called after calling bibShowBits to skip the number of bits that
 *      were actually needed. If bibShowBits fetched more bits than there were
 *      bits in bitbuf->currentBits, calls bibSkipBitsFunc to clean up.
 *
 * Returns:
 *      -
 *
 */
#define bibSkipBits(bitbuf, n) \
  (bitbuf)->bitpos -= (n); \
  if ((bitbuf)->bitpos < 0) { \
    (bitbuf)->bitpos += (n); \
    bibSkipBitsFunc(bitbuf, n); \
  }



#endif  /* #ifndef _BITBUFFER_H_ */