bbitio.h

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/*
 *
 * Totally changed 6-12-95
 *
 * we now properly write bits left->right
 * 
 * all previous programs must be modified to be accomodate this
 *
 * new 6-13 : after FlushWrite, you must read the return value of FlushWrite
 *
 */

#ifndef BIT_IO_H
#define BIT_IO_H

#include <crblib/inc.h>

typedef struct BitIOInfo {
  ulong BitBuffer;
  int BitsToGo;
  ubyte *BitArray;
  ubyte *BitArrayPtr;
} bitInfo;

/*externs in BitIO.c :*/

extern struct BitIOInfo * BitIO_Init(ubyte *Array);
extern void BitIO_CleanUp(struct BitIOInfo * BII);
extern long BitIO_FlushWrite(struct BitIOInfo * BII); /*returns length of data*/
extern void BitIO_ResetArray(struct BitIOInfo * BII,ubyte *Array);
extern void BitIO_ResetArrayPtr(struct BitIOInfo * BII,ubyte *Array);
extern ubyte * BitIO_GetArray(struct BitIOInfo * BII);
extern long BitIO_GetPos(struct BitIOInfo * BII);
extern long BitIO_GetPosD(struct BitIOInfo * BII);
extern void BitIO_FlushRead(struct BitIOInfo * BII);

extern void BitIO_WriteUnary(struct BitIOInfo * BII,ulong val);
extern ulong BitIO_ReadUnary(struct BitIOInfo * BII);

/*macros:*/

/****

BII = (struct BitIOInfo * BII)

void BitIO_WriteBit(BII,ubyte Bit);
void BitIO_WriteZeroBit(BII);
void BitIO_InitRead(BII);
void BitIO_ReadBit(BII,bool Bit); / /fills out Bit

*****/

#define BitIO_WriteOneBit(BII) BitIO_WriteBit(BII,1)

#define BitIO_StepArray(BII,step)	BII->BitArrayPtr += step;

/*
 *  Write a Bit to the BII - Bit may be True or False (need not be 0 or 1)
 *  params: struct BitIOInfo * BII,ubyte Bit
 *
 */
#define BitIO_WriteBit(BII,Bit) do { \
BII->BitBuffer += BII->BitBuffer + (Bit);         \
BII->BitsToGo--;                                  \
if ( ! BII->BitsToGo )                            \
  {                                               \
  *(BII->BitArrayPtr)++ = (ubyte)BII->BitBuffer;  \
  BII->BitsToGo = 8;                              \
  BII->BitBuffer = 0;                             \
  }                                               \
} while(0)                                                
/* End BitIO_WriteBit */

#define BitIO_WriteZeroBit(BII) do { \
BII->BitBuffer += BII->BitBuffer;                 \
BII->BitsToGo--;                                  \
if ( ! BII->BitsToGo )                            \
  {                                               \
  *(BII->BitArrayPtr)++ = (ubyte)BII->BitBuffer;         \
  BII->BitsToGo = 8;                              \
  BII->BitBuffer = 0;                             \
  }                                               \
} while(0)                                                
/* End BitIO_WriteZeroBit */

/*
 *  Reads bits into BitBuffer from BitArray
 *  must be done before any _Read commands
 *
 */
#define BitIO_InitRead(BII) do { BII->BitBuffer = *BII->BitArrayPtr++; BII->BitsToGo = 8; } while(0)
/* End BitIO_InitRead */

extern const int BBitIOReadBitMask;

/*
 *  Read a bit from BII into (bool Bit)
 *
 */
#define BitIO_ReadBit(BII,Bit)      do { \
if ( BII->BitBuffer & BBitIOReadBitMask )         \
  Bit = 1;                                        \
else                                              \
  Bit = 0;                                        \
BII->BitBuffer += BII->BitBuffer;                 \
BII->BitsToGo --;                                 \
if ( BII->BitsToGo == 0 )                         \
  {                                               \
  BII->BitBuffer = *(BII->BitArrayPtr)++;         \
  BII->BitsToGo = 8;                              \
  }                                               \
} while(0)                                        \
/* End BitIO_ReadBit */

#endif /* BIT_IO_H */