哈夫曼图片压缩及解压

其他 2019-05-10 19:41:25 阅读次数: 0

哈夫曼图片压缩及解压

文件 功能
Huffman 哈夫曼编码
compress 解压 
//Compress.h
#ifndef COMPRESS_H
#define COMPRESS_H
typedef unsigned char * buffer;
int Compress(const char *pFilename);
unsigned char Str2byte(const char *pBinStr);
int Encode(const char*pFilename, const HuffmanCode pHC,buffer &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, unsigned char * pBuffer, const int nSize);
int InitHead(const char *pFilename, HEAD &sHead);
int UnCompress(const char*pFilename);
#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
//huffman.cpp
#include<iostream>
#include<cstring>
#include"huffman.h"
#pragma warning( disable : 4996)
using namespace std;
/*
void PreorderTraverse(int root, HuffmanTree pHT)
{
    cout << pHT[root].weight << " ";//访问节点
    if (pHT[root].lchild)//左孩子
    {
        PreorderTraverse(pHT[root].lchild, pHT);
    }
    if (pHT[root].rchild)//右孩子
    {
        PreorderTraverse(pHT[root].rchild, pHT);
    }
}
*/
int HuffmanCoding(HuffmanCode &pHC, HuffmanTree &pHT)
{
    pHC = (HuffmanCode)malloc((SIZE + 1) * sizeof(char*));
    //无栈非递归遍历 
    char cd[SIZE] = { '\0' };//记录访问路径
    int cdlen = 0;//记录当前路径长度
    for (int i = 1; i < 512; i++)
    {
        pHT[i].weight = 0;//遍历 Huffman树时用作节点的状态标志
    }

    int p = 2*SIZE-1;//根节点
    while (p != 0)
    {
        if (pHT[p].weight == 0)//向左
        {
            pHT[p].weight = 1;
            if (pHT[p].lchild != 0)
            {
                p = pHT[p].lchild;
                cd[cdlen++] = '0';
            }
            else if (pHT[p].rchild == 0)//登记叶子节点的字符编码
            {
                pHC[p] = (char*)malloc((cdlen+1) * sizeof(char));
                cd[cdlen] = '\0';
                strcpy(pHC[p], cd);//复制编码
            }
        }
        else if (pHT[p].weight == 1)//向右
        {
            pHT[p].weight = 2;
            if (pHT[p].rchild != 0)//右孩子为叶子节点
            {
                p = pHT[p].rchild;
                cd[cdlen++] = '1';
            }
        }
        else
        {
            //退回父节点，编码长度减1
            pHT[p].weight = 0;
            p = pHT[p].parent;
            --cdlen;
        }
//      printf("*");
    }
    return OK;
}

int Select(HuffmanTree pHT, int nSize)
{
    int minValue = 0x7FFFFFFF;//最小值
    int min = 0;
    //找到最小权值的元素序号
    for (int i = 1; i <= nSize; i++)
    {
        if (pHT[i].parent == 0 && pHT[i].weight < minValue)
        {
            minValue = pHT[i].weight;
            min = i;
        }
    }
    return min;
}

void TestHufTree(HuffmanTree pHT)
{
    for (int i = 1; i < 2*SIZE; i++)
    {
        printf("pHT[%d]\t%d\t%d\t%d\t%d\n", i, pHT[i].weight, pHT[i].parent,pHT[i].lchild,pHT[i].rchild);
    }
}

int HfmTree(HuffmanTree &pHT, int *w, int n)
{
    int m = 2 * n - 1;
    pHT = (HuffmanTree)malloc((m + 1) * sizeof(HTNode));
    if (!pHT)
    {
        cerr << "内存分配失败! " << endl;
        return -1;
    }
    //初始化树
    HuffmanTree p = pHT + 1;//0号单元不使用
    for (int i = 0; i < m; i++)
    {
        p->weight = (i < n) ? w[i] : 0;
        p->parent = 0;
        p->lchild = 0;
        p->rchild = 0;
        p++;
    }
    for (int i = n + 1; i <= m; i++)
    {
        //第一个最小元素
        int s1 = Select(pHT, i - 1);//找出前i-1个中最小元素
        pHT[s1].parent = i;

        //第二个最小元素
        int s2 = Select(pHT, i - 1);
        pHT[s2].parent = i;

        pHT[i].weight = pHT[s1].weight + pHT[s2].weight;
        pHT[i].lchild = s1;
        pHT[i].rchild = s2;
    }
    return 0;
}

void TestHufCode(int root, HuffmanTree pHT, HuffmanCode pHC)
{
    if (pHT[root].lchild == 0 && pHT[root].rchild == 0)
    {
        printf("0x%02X %s\n", root - 1, pHC[root]);
    }
    if (pHT[root].lchild)//访问左孩子
    {
        TestHufCode(pHT[root].lchild, pHT, pHC);
    }
    if (pHT[root].rchild)
    {
        TestHufCode(pHT[root].rchild, pHT, pHC);
    }
}

void TestHufTreeN(int root, HuffmanTree pHT)
{
    cout << pHT[root].weight << "\t"<<pHT[root].lchild<<"\t"<<pHT[root].rchild<<"\t"<<pHT[root].parent<<"\n";
    if (pHT[root].lchild != 0)
    {
        TestHufTreeN(pHT[root].lchild, pHT);
    }
    if (pHT[root].rchild != 0)
    {
        TestHufTreeN(pHT[root].rchild, pHT);
    }
}
//Compress.cpp
#include"huffman.h"
#include"Compress.h"
#include<iostream>
#pragma warning( disable : 4996)
using namespace std;
//Compress
//InitHead
//Encode
//Str2byte
//WriteFile
unsigned char Str2byte(const char *pBinStr)
{
    unsigned 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 << "成功生成哈夫曼树" << endl;
//  TestHufTree(hfmt);
    //  TestHufTreeN(511, hfmt);
    HuffmanCode hfmc=(HuffmanCode)malloc((SIZE+1)*sizeof(char*));
//  for (int i = 1; i <= SIZE; i++)
//      hfmt[i].weight = weight[i - 1]
    //根据哈夫曼树进行编码
    HuffmanCoding(hfmc, hfmt);
    cout << "成功完成哈夫曼编码" << endl;
//  cout << "先序遍历哈夫曼树输出编码信息：" << endl;
//  TestHufCode(2 * SIZE - 1, hfmt, hfmc);//测试哈夫曼编码
//  cout << "压缩后的文件编码：" << endl;

    //计算编码缓冲区大小
    int nSize = 0;
    for (int i = 0; i < 256; i++)
    {
        nSize += weight[i] * strlen(hfmc[i+1]);
    }
    nSize = (nSize % 8) ? nSize / 8 + 1 : nSize / 8;

//  cout <<"nSize = "<<nSize << endl << endl;

    //对原文件进行压缩编码
    unsigned char* pBuffer = NULL;
    pBuffer = (unsigned char *)malloc(nSize*sizeof(unsigned char));
    memset(pBuffer, 0, (nSize) * sizeof(unsigned char));
//  cout << "begin: " << strlen(pBuffer) << endl;
////    cout << "----";
//  int n;
//  cout << "input n:";
//  cin >> n;
    //将编码写入缓冲区
    Encode(pFilename, hfmc, pBuffer, nSize);
//  cout << "after: " << strlen(pBuffer) << endl;
//  cout << "len of puf  = " << strlen(pBuffer) << endl;
//  cout << "!pBuffer = " << !pBuffer << endl;
    if (!pBuffer)
    {
        cout << "!pBuffer = " << !pBuffer << endl;
        return -1;
    }
    cout << "\n压缩完毕" << endl;
    //for (int i = 1; i < nSize; i++)
    //{
    //  printf("%X\n", pBuffer[i]);
    //}

    HEAD sHead;
    InitHead(pFilename, sHead);
    cout <<"原文件"<< pFilename<<"大小为：" << sHead.length << "Byte" << endl;
    int len_after = WriteFile(pFilename, sHead, pBuffer, nSize);
    cout << "大小为：" << len_after << "Byte \n头文件sHead大小为：" << sizeof(sHead)<<"Byte"<<endl;
    cout << "压缩比率：" << (double)len_after * 100 / sHead.length << "%" << endl;
    free(hfmt);
    free(hfmc);
    free(pBuffer);
    return OK;
}


int Encode(const char*pFilename, const HuffmanCode pHC,buffer &pBuffer, const int nSize)
{
    //开辟缓冲区
//  cout << "+++++";
    FILE* in = fopen(pFilename, "rb");
    if (in == NULL)
    {
        cout << "Failed to open the file!" << endl;
        exit(0);
    }
    pBuffer = (unsigned char*)malloc(nSize * sizeof(unsigned char));
    if (!pBuffer)
    {
        cerr << "开辟缓冲区失败" << endl;
        return -1;
    }
    cout << "loading";
    int sign = 0;//用于控制小数点输出
    char cd[SIZE] = { 0 };//工作区
    int pos = 0;//缓冲区指针
    int ch;
    //扫描文件，根据huffmman编码表对其进行压缩，压缩结果暂存到缓冲区中
    while ((ch = getc(in)) != EOF)
    {
        if (sign % 1000 == 1)
            printf(".");
        sign++;
        strcat(cd, pHC[ch+1]);//从HC复制编码串到cd


        //打印压缩后的文件编码
//      printf("%s", pHC[ch + 1]);


        //压缩编码
        while (strlen(cd) >= 8)
        {
            //截取字符串左边的8个字符，编码成字节
            pBuffer[pos++] = Str2byte(cd);
            //字符串整体左移8个字节
            for (int i = 0; i < SIZE - 8; i++)
            {
                cd[i] = cd[i + 8];
            }
        }
    }
    if (strlen(cd) > 0)
    {
        pBuffer[pos++] = Str2byte(cd);
    }
    fclose(in);
//  printf("%", pBuffer);
    return OK;
}

int InitHead(const char *pFilename, HEAD &sHead)
{
    //初始化文件头
    strcpy(sHead.type, "HUF");//文件类型
    sHead.length = 0;//原文件长度
    for (int i = 0; i < SIZE; i++)
    {
        sHead.weight[i] = 0;
    }
    FILE *in = fopen(pFilename, "rb");
    int ch;
    while ((ch = fgetc(in)) != EOF)
    {
        sHead.weight[ch]++;
        sHead.length++;
    }
    fclose(in);
    in = NULL;
    return OK;
}

int WriteFile(const char*pFilename, const HEAD sHead, unsigned char * pBuffer, const int nSize)
{
    //生成文件名
    char filename[256] = { 0 };
    strcpy(filename, pFilename);
    strcat(filename, ".huf");
    //以二进制流形式打开文件
    FILE *out = fopen(filename, "wb");
    //写文件头
    fwrite(&sHead, sizeof(sHead), 1, out);
    //写压缩后的编码
    fwrite(pBuffer, sizeof(char), nSize, out);
    //关闭文件，释放文件指针
    fclose(out);
    out = NULL;
    cout << "生成压缩文件：" << filename << endl;
    int len = sizeof(HEAD) + strlen(pFilename) + 1 + nSize;
    return len;
}
//解压函数
int UnCompress(const char*pFilename)
{
    char outputfile[255];
    FILE *ifp, *ofp;
    ifp = fopen(pFilename, "rb");//打开.huf文件
    if (!ifp)
    {
        cerr << "Failed to open this file!" << endl;
        return -1;
    }
    cout << "输入解压后的文件名,(原文件名为" << pFilename << "): " << endl;
    cin >> outputfile;
//  strcpy(outputfile, "d:\\aaa.png");
    ofp = fopen(outputfile, "wb");
    if (!ofp)
    {
        cerr << "Failed to open this file!" << endl;
        return -1;
    }
    HEAD sHead;
    //读文件头
    fread(&sHead, sizeof(HEAD), 1, ifp);
    HuffmanTree hfmt = NULL;
    HfmTree(hfmt, sHead.weight, 256);
    HuffmanCode hfmc = NULL;
    HuffmanCoding(hfmc, hfmt);
    int max = 0;
    for (int k = 1; k <= 256; k++) {
        if (strlen(hfmc[k]) > max) {
            max = strlen(hfmc[k]);
        }//找出最长的编码
    }
    //
    int nSize = 0;
    for (int i = 0; i < 256; i++)
    {
        nSize += sHead.weight[i] * strlen(hfmc[i + 1]);
    }
    nSize = (nSize % 8) ? nSize / 8 + 1 : nSize / 8;
    cout << "nsize =  " << nSize << endl;
//  unsigned char *pBuffer = NULL;
    unsigned char* pBuffer = NULL;
    pBuffer = (unsigned char *)malloc(nSize * sizeof(unsigned char));
    memset(pBuffer, 0, (nSize) * sizeof(unsigned char));
//  pBuffer = (unsigned char*)malloc(nSize*sizeof(unsigned char));
    fread(pBuffer, sizeof(unsigned char), nSize, ifp);
    //for (int i = 0; i < nSize; i++)
    //{
    //  printf("%x\n", pBuffer[i]);
    //}
    char ch[SIZE] = { 0 };
    unsigned char c;
    for (int i = 0; i < nSize; i++)
    {
//      printf("%x\n", pBuffer[i]);
        char s[SIZE] = { 0 };
        char buf[SIZE] = { 0 };
        _itoa(pBuffer[i], buf, 2);

        for (int k = 8; k > strlen(buf); k--)
        {
            strcat(s, "0");
        }
        strcat(s, buf);
        strcat(ch, s);
//      cout << "ch = " << ch << endl;
        int m = 2 * SIZE - 1;
        while (strlen(ch) >= max)
        {
//          cout << "**";
            int j = 0;
            while (ch[j] != '\0')
            {
//              cout << "....";
                int t = m;
                while (hfmt[t].lchild != 0 && hfmt[t].rchild != 0)
                {
                    if (ch[j] == '0')
                    {
                        t = hfmt[t].lchild;
                    }
                    else
                    {
                        t = hfmt[t].rchild;
                    }
                    j++;
                }
                c = (unsigned char)(t - 1);
//              cout << (t - 1) << endl;
                fwrite(&c, 1, 1, ofp);

                for (int b = 0; b < SIZE - j; b++)
                {
                    ch[b] = ch[b + j];
                }
                break;
            }
//          cout << "::::";
        }
    }
    cout << "解压成功" << endl;
    fclose(ifp);
    fclose(ofp);

    return OK;
}

//main.cpp
#include"huffman.h"
#include"Compress.h"
#include<iostream>
#include<cstdlib>
using namespace std;
#pragma warning( disable : 4996)

int main()
{
    cout << "= = = = = = = =Huffman 文件压缩= = = = = = = =" << endl;
    cout << "**1.压缩文件" << endl;
    cout << "**2.解压文件" << endl;
    cout << "= = = = = = = = = =  = = = = = = = = = = = = =" << endl;
    int choose = 0;
    cout << "----选择功能：";
    cin >> choose;
    while (choose == 1 || choose == 2)
    {
        if (choose == 1)
        {
            cout << "请输入文件名：";
            char filename[256];
            cin >> filename;
            Compress(filename);
        }
        else if (choose == 2)
        {
            cout << "输入你要解压的文件名(.huf后缀): ";
            char newfilename[SIZE] = { 0 };
            cin >> newfilename;
            //  strcpy(newfilename, "d:\\t.png.huf");
            UnCompress(newfilename);
        }
        else
            break;
        cout << "----选择功能：";
        cin >> choose;
    }


//  system("pause");
    return 0;
}

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