源程序1.txt

次文件是一个压缩算法的几个实例

// bitio.cpp

#include <stdio.h>
#include <stdlib.h>
#include "bitio.h"
#include "errhand.h"

#define PACIFIER_COUNT	2047

BIT_FILE* OpenOutputBitFile( 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, "wb");
	bit_file->rack = 0;
	bit_file->mask = 0x80;
	bit_file->pacifier_counter = 0;
	return bit_file;
}

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

void OutputBit( 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++ & PACIFIER_COUNT) == 0)
			putc('.', stdout);
		bit_file->rack = 0;
		bit_file->mask = 0x80;
	}
}

void OutputBits( 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++ & PACIFIER_COUNT) == 0)
				putc('.', stdout);
			bit_file->rack = 0;
			bit_file->mask = 0x80;
		}
		mask >>= 1;
	}
}

int InputBit( 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++ & PACIFIER_COUNT) == 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_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++ & PACIFIER_COUNT) == 0)
					putc('.', stdout);
		}
		if (bit_file->rack & bit_file->mask)
			return_value |= mask;
		mask >>= 1;
		bit_file->mask >>= 1;
		if (bit_file->mask == 0)
			bit_file->mask = 0x80;
	}
	return return_value;
}

void FilePrintBinary( FILE* file, unsigned int code, int bits )
{
	unsigned int mask;
	mask = 1L << (bits - 1);
	while( mask != 0 )
	{
		if (code & mask)
			fputc('1', file);
		else
			fputc('0', file);
		mask >>= 1;
	}
}