stream.cpp

In term project, we will take the baseline JPEG codec in ARM-based platform system as an example to

#include "stream.h"
#include <stdio.h>
#include <stdlib.h>

FILE* file=NULL;

BitStream::BitStream():Buffer(0), BufferLength(0), ByteStuffing(false)
{ Name[0]=0; }

BitStream::~BitStream()
{ if( file!=NULL ) Close(); }

bool BitStream::Open(const char* name, const char* attr)
{ file=fopen(name, attr);

  if( file==NULL ) return false;

  int i=0;
  do{ Name[i]=name[i];
      i=i+1;
      if( i==32 ){ Name[31]=0; break; }
    }while( name[i]!=0 );

  return true;
}

bool BitStream::Close()
{ if( file!=NULL )
    {
      if( BufferLength!=0 ) fputc(Buffer, file);

      Buffer=0;
      BufferLength=0;

      fclose(file);
      file=NULL;
      return true;
    }
  return false;
}

bool BitStream::IsEndOfStream()
{ if( file==NULL ) return true;

  if( BufferLength!=0 ) return false;

  if( feof(file)==0 ) return false;

  return true;
}

/*----------------------------------------------------------------------------*/

bool BitStream::Put(Byte val)
{ if( file==NULL ) return false;

  if( BufferLength>=8 )
    { fputc(Buffer,file);
      if( ByteStuffing==true && Buffer==(Byte)0xFF )
          fputc(0x00,file);
      Buffer=0;
      BufferLength=0;
    }

  Byte mask=(0x80>>BufferLength);

  switch( val )
    { case 0: mask=~mask; Buffer&=mask; break;
      case 1:             Buffer|=mask; break;
      default: break;
    }

  BufferLength+=1;

  return true;
}

bool BitStream::Get(Byte* val)
{ if( file==NULL ) return false;

  if( BufferLength==0 )
    {
      Buffer=fgetc(file);

      if( feof(file)!=0 ){ Buffer=0; BufferLength=0; return false; }

      if( ByteStuffing==true && Buffer==(Byte)0xFF )
          fgetc(file); /*