武汉理工大学数据结构实验—哈夫曼树压缩图片

最新推荐文章于 2023-02-02 00:54:49 发布

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最新推荐文章于 2023-02-02 00:54:49 发布 · 3.2k 阅读

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本文介绍了一种基于霍夫曼编码的文件压缩算法实现，包括霍夫曼树的构建、编码过程、文件读写及压缩率计算。通过具体代码示例展示了如何对文件进行高效压缩。

Compress.h

#ifndef COMPRESS_H
#define COMPRESS_H
int Compress(const char* pFilename);
char Str2byte(const char* pBinStr);
int Encode(const char* pFilename, const HuffmanCode pHC, char* pBuffer, const int nSize);

struct HEAD
{
   
   
	char type[4];//文件类型
	int length;//原文件长度
	int weight[256];//权值数值
};
int WriteFile(const char* pFilename, const HEAD sHead, const char* pBuffer, const int nSize);
int InitHead(const char* pFilename, HEAD& sHead);
#endif

Huffman.h

#ifndef HUFFMAN_H
#define HUFFMAN_H
#define OK 1
#define SIZE 256
struct HTNode {
   
   
	int weight;//权值
	int parent;//父节点
	int lchild;//左孩子
	int rchild;//右孩子
};
typedef HTNode* HuffmanTree;//动态分配数组存储Huffman树
typedef char** HuffmanCode;//动态分配哈夫曼编码表


//void PreorderTraverse(int root, HuffmanTree pHT);
int HuffmanCoding(HuffmanCode& pHC, HuffmanTree& pHT);
int Select(HuffmanTree pHT, int nSize);
void TestHufTree(HuffmanTree pHT);
void TestHufCode(int root, HuffmanTree pHT, HuffmanCode pHC);
void TestHufTreeN(int root, HuffmanTree pHT);

int HfmTree(HuffmanTree& pHT, int* w, int n);

#endif

Compress.cpp

#include"huffman.h"
#include"Compress.h"
#include<iostream>
#pragma warning( disable : 4996)
using namespace std;
//Compress
//InitHead
//Encode
//Str2byte
//WriteFile
char Str2byte(const char* pBinStr)
{
   
   
	char b = 0x00;
	for (int i = 0; i < 8; i++)
	{
   
   
		b = b << 1;
		if (pBinStr[i] == '1')
		{
   
   
			b = b | 0x01;
		}
	}
	return b;
}

int Compress(const char* pFilename)
{
   
   
	int weight[256] = {
   
    0 };
	//以二进制打开文件
	FILE* in = fopen(pFilename, "rb");
	if (in == NULL)
	{
   
   
		cout << "Failed to open the file!" << endl;
		exit(0);
	}
	cout << "成功打开文件 " << pFilename << endl;
	int ch;
	while ((ch = getc(in)) != EOF)
	{
   
   
		weight[ch]++;
	}
	fclose(in);
	//cout << "Byte Weight" << endl;
	//for (int i = 0; i < SIZE; i++)
	//{
   
   
	//    printf("0x%02X %d\n", i, weight[i]);
	//}

	HuffmanTree hfmt;
	HfmTree(hfmt, weight, SIZE);
	cout <<