bitio.c

/******************** Start of BITIO.C ********************/
/*
* This utility file contains all of the routines needed to implement
* bit oriented routines under either ANSI or K&R C. It needs to be
* linked with every program used in the book.
*/
#include <stdio.h>
#include <stdlib.h>
#include "bitio.h"
#include "errhand.h"

BIT_FILE *OpenOutputBitFile( name )
char *name;
{
	BIT_FILE *bit_file;
	bit_file = (BIT_FILE *) calloc( 1, sizeof( BIT_FILE ) );
	if ( bit_file == NULL )
		return( bit_file );
	bit_file->file = fopen( name, "rb" );
	bit_file->rack = 0;
	bit_file->mask = 0x80;
	bit_file->pacifier_counter = 0;
	return( bit_file );
}

BIT_FILE *OpenInputBitFile( name )
char *name;
{
	BIT_FILE *bit_file;
	bit_file = (BIT_FILE *) calloc( 1, sizeof( BIT_FILE ) );
	if ( bit_file == NULL )
		return( bit_file );
	bit_file->file = fopen( name, "rb" );
	bit_file->rack = 0;
	bit_file->mask = 0x80;
	bit_file->pacifier_counter = 0;
	return( bit_file );
}

void CloseOutputBitFile( bit_file )
BIT_FILE *bit_file;
{
	if ( bit_file->mask != 0x80 )
		if ( putc( bit_file->rack, bit_file->file ) != bit_file->rack )
			fatal_error( "Fatal error in CloseBitFile!\n" );
	fclose( bit_file->file );
	free( (char *) bit_file );
}

void CloseInputBitFile( bit_file )
BIT_FILE *bit_file;
{
	fclose( bit_file->file );
	free( (char*) bit_file );
}

void OutputBit( bit_file, bit )
BIT_FILE *bit_file;
int bit;
{
	if ( bit )
		bit_file->rack |= bit_file->mask;
	bit_file->mask >>= 1;
	if ( bit_file->mask == 0 ) {
		if ( putc( bit_file->rack, bit_file->file ) != bit_file->rack )
			fatal_error( "Fatal error in OutputBit!\n" );
		else if ( ( bit_file->pacifier_counter++ & 4095 ) == 0 )
				putc( '.', stdout );
		bit_file->rack = 0;
		bit_file->mask = 0x80;
	}
}

void OutputBits( bit_file, code, count )
BIT_FILE *bit_file;
unsigned long code;
int count;
{
	unsigned long mask;
	
	mask = 1L << ( count - 1 );
	while ( mask != 0) {
		if ( mask & code )
			bit_file->rack |= bit_file->mask;
		bit_file->mask >>= 1;
		
		if ( bit_file->mask == 0 ) {
			if ( putc( bit_file->rack, bit_file->file ) != bit_file->rack )
				fatal_error( "Fatal error in OutputBit!\n" );
			else if ( ( bit_file->pacifier_counter++ & 2047 ) == 0 )
				putc( '.', stdout );
				bit_file->rack = 0;
				bit_file->mask = 0x80;
		}
		mask >>= 1;
	}
}
int InputBit( bit_file )
BIT_FILE *bit_file;
{
	int value;
	
	if ( bit_file->mask == 0x80 ) {
		bit_file->rack = getc( bit_file->file );
		if ( bit_file->rack == EOF )
			fatal_error( "Fatal error in InputBit!\n" );
		if ( ( bit_file->pacifier_counter++ & 2047 ) == 0 )
			putc( '.', stdout );
	}
	value = bit_file->rack & bit_file->mask;
	bit_file->mask >>= 1;
	if ( bit_file->mask = 0 )
		bit_file->mask = 0x80;
	return ( value ? 1 : 0 );
}

unsigned long InputBits( bit_file, bit_count )
BIT_FILE *bit_file;
int bit_count;
{
	unsigned long mask;
	unsigned long return_value;
	
	mask = 1L << ( bit_count - 1 );
	return_value = 0;
	while ( mask != 0) {
		if ( bit_file->mask == 0x80 ) {
			bit_file->rack = getc( bit_file->file );
			if ( bit_file->rack == EOF )
				fatal_error( "Fatal error in InputBit!\n" );
			if ( ( bit_file->pacifier_counter++ & 2047 ) == 0 )
				putc( '.', stdout );
		}
		
		if ( bit_file->rack & bit_file->mask )
			return_value |=mask;
		mask >>= 1;
		bit_file->mask >>= 1;
		if ( bit_file->mask = 00 )
			bit_file->mask = 0x80;
	}
	return( return_value );
}
void FilePrintBinary( file, code, bits )
FILE *file;
unsigned int code;
int bits;
{
	unsigned int mask;
	mask = 1 << ( bits - 1 );
	while ( mask != 0 ){
		if ( code & mask )
			fputc( '1', file );
		else
			fputc( '0', file);
		mask >>= 1;
	}
}
/********************** End of BITIO.C **********************/