C++ QT实现类似于Bandizip解压缩的功能

#include "compression.h" #include <qmath.h> Compression::Compression() { } //把二进制串转化为int型，即将压缩时每8个二进制位的字符串转化为ASCII码，传入压缩后的文件 int binarystringtoint(string binarystring) { int sum = 0; for(int i=0;i<binarystring.size();i++) { if(binarystring[i]=='1') { int j = pow(2,binarystring.size()-i-1); sum += j; } } return sum; } //把int型转换为二进制串，解压时使用 string inttobinarystring(int value) { string binarystring; while(value>0) { int r = value%2; if(r==1) binarystring.insert(0,1,'1'); else binarystring.insert(0,1,'0'); value = value/2; } //不足8位，后补0 if(binarystring.size()<8) { binarystring.insert(0,8-binarystring.size(),'0'); } return binarystring; } //哈夫曼树结点权重比较 bool compare(HuffmanTreeNode* node1, HuffmanTreeNode* node2) { return node1->Weight.second < node2->Weight.second; } //删除申请空间中哈夫曼树的函数 void Compression::Delete(HuffmanTreeNode *&root) { if(root==NULL) return; //递归调用 Delete(root->leftson); Delete(root->rightson); } //权重映射的初始化 void Compression::Weightmap_Init(QFile& in) { QByteArray a; while (!in.atEnd()) { a=in.read(1024); //一次性读取1024个字节，不足1024个字节则读取全部 string b=a.toStdString(); //转换为string for(int i=0;i<b.size();i++) { unsigned char ch=b[i]; source_string += ch; weightmap[ch]++; } } } //按照哈夫曼编码映射初始化类中的binarystring void Compression::BinaryString_Init() { for(int i=0;i<source_string.size();i++) binary_string += passwordmap[source_string[i]]; } //建立哈夫曼结点，进行初始化操作 HuffmanTreeNode* Compression::MakehuffmanTreeNode(int i) { HuffmanTreeNode* huffman = new HuffmanTreeNode; huffman->Weight.first = i; huffman->Weight.second = weightmap[i]; huffman->tag = 0; //是叶子结点 huffman->leftson = NULL; huffman->rightson = NULL; return huffman; } //初始化结点容器 void Compression::HuffmanTreeVector_Init() { for (map<unsigned char, int>::iterator it = weightmap.begin(); it != weightmap.end(); it++) { HuffmanTreeNode* huffman = MakehuffmanTreeNode(it->first); container.push_back(huffman); } } //建立哈夫曼树 void Compression::HuffmanTree_Init() { while (container.size() != 1) //也就是一直到生成根节点 { //从头到尾开始排序，权重小的放底下 sort(container.begin(), container.end(), compare); int sum = container[0]->Weight.second + container[1]->Weight.second; HuffmanTreeNode* newhuffman = new HuffmanTreeNode; //新建哈夫曼结点 newhuffman->Weight.second = sum; newhuffman->Weight.first = 0; newhuffman->tag = 1; //新生成的标记为非叶子结点 newhuffman->leftson = container[0]; newhuffman->rightson = container[1]; container.erase(container.begin()); //删除后迭代器会顺移到下一位 container.erase(container.begin()); container.push_back(newhuffman); } } //递归更新哈夫曼编码函数 void Compression::ZipPassword_Init(HuffmanTreeNode* &root, string& password) { if (root != NULL && !root->tag) { root->zippassword = password; passwordmap[root->Weight.first] = password; } if (root->leftson != NULL) { //向左分支设为0 ZipPassword_Init(root->leftson, password += "0"); password.pop_back(); } if (root->rightson != NULL) { //向右分支设为1 ZipPassword_Init(root->rightson, password+="1"); password.pop_back(); } } //压缩函数 void Compression::zip(QString path) { clock_t begin=clock(); //记录开始时间 QFile openfile(path); //创建QFile if(!openfile.open(QIODevice::ReadOnly)) //打开文件,若不成功，发射出错信号，结束 { QMessageBox::information(NULL,QString("警告"),QString("文件打开失败")); emit error(); return; } Weightmap_Init(openfile); //权重映射初始化 emit mysignal(10); //更新进度条 HuffmanTreeVector_Init(); //哈夫曼结点容器初始化 emit mysignal(20); HuffmanTree_Init(); //构建哈夫曼树 emit mysignal(30); string empty=""; ZipPassword_Init(container[0],empty); //哈夫曼编码映射初始化 emit mysignal(40); BinaryString_Init(); //获取二进制串 emit mysignal(50); path+=".HuffmanZip"; //压缩后的文件格式后缀 openfile.close(); //关闭openfile QFile savefile(path); //创建新的Qfile进行压缩文件的写入 savefile.open(QIODevice::WriteOnly); //打开 QDataStream out(&savefile); //利用QdataStream进行接下来的操作 int size = passwordmap.size(); if (size == 256) size = 0; //因为256无法用一个字节保存 int length = 0; out<<size; //传入哈夫曼编码映射数量 length++; double k=1; //迭代器 for (map<unsigned char, string>::iterator it = passwordmap.begin(); it != passwordmap.end(); it++) { emit mysignal(50+double(25*k++)/passwordmap.size()); int first = it->first; out<<first; //传入key值 length++; string second = it->second; int size = second.size(); out<<size; //传入value值的长度 length++; int n = 8 - second.size() % 8; if (n) { second.append(n, '0'); //补0 } for (int i = 0; i < second.size(); i += 8) { string k = second.substr(i, 8); int temp = binarystringtoint(k); unsigned char ch = temp; out<<ch; //传入value值 length++; } } int n = 8 - binary_string.size() % 8; if (n) { binary_string.append(n, '0'); } length++; int totalbitsize = binary_string.size() / 8; for (int i = 0; i < binary_string.size(); i += 8) { emit mysignal(75+double(25*i)/binary_string.size()); //分8个字节依次传入 string k = binary_string.substr(i, 8); int temp = binarystringtoint(k); unsigned char ch = temp; out<<ch; length++; } unsigned char temp=n; out<<temp; //传入补0数量 length++; emit mysignal(100); int newlength=savefile.size(); savefile.close(); clock_t end=clock(); //结束时间 //弹窗提示本次压缩情况 QString tip("理论压缩比:"); tip+=QString::number(double(totalbitsize * 100) / source_string.size()); tip+="%,实际压缩比："; tip+=QString::number(double(newlength * 100) / source_string.size()); tip+="%,压缩用时："; tip+=QString::number(double(end-begin)/CLOCKS_PER_SEC); tip+="s"; QMessageBox::about(this,"压缩说明",tip); //结束后的清空处理 weightmap.clear(); passwordmap.clear(); source_string.clear(); binary_string.clear(); Delete(container[0]); container.clear(); } //解压函数 void Compression::unzip(QString path) { clock_t begin=clock(); //获取解压开始时间 if(path.right(11)!=".HuffmanZip")