C++ zlib使用

C++中使用zlib库可以实现数据的压缩和解压缩。下面是一个简单的示例代码：

#include <iostream>
#include <fstream>
#include <string>
#include <zlib.h>

// 压缩函数
bool compressFile(const std::string& sourceFile, const std::string& destFile) {
    std::ifstream inFile(sourceFile, std::ios::binary);
    std::ofstream outFile(destFile, std::ios::binary);
    if (!inFile || !outFile) {
        return false;
    }

    z_stream stream;
    stream.zalloc = Z_NULL;
    stream.zfree = Z_NULL;
    stream.opaque = Z_NULL;
    if (deflateInit(&stream, Z_DEFAULT_COMPRESSION) != Z_OK) {
        return false;
    }

    char inBuffer[1024];
    char outBuffer[1024];
    stream.avail_in = inFile.readsome(inBuffer, sizeof(inBuffer));
    stream.next_in = reinterpret_cast<Bytef*>(inBuffer);

    do {
        stream.avail_out = sizeof(outBuffer);
        stream.next_out = reinterpret_cast<Bytef*>(outBuffer);
        deflate(&stream, Z_FINISH);
        outFile.write(outBuffer, sizeof(outBuffer) - stream.avail_out);
    } while (stream.avail_out == 0);

    deflateEnd(&stream);
    inFile.close();
    outFile.close();

    return true;
}

// 解压缩函数
bool decompressFile(const std::string& sourceFile, const std::string& destFile) {
    std::ifstream inFile(sourceFile, std::ios::binary);
    std::ofstream outFile(destFile, std::ios::binary);
    if (!inFile || !outFile) {
        return false;
    }

    z_stream stream;
    stream.zalloc = Z_NULL;
    stream.zfree = Z_NULL;
    stream.opaque = Z_NULL;
    if (inflateInit(&stream) != Z_OK) {
        return false;
    }

    char inBuffer[1024];
    char outBuffer[1024];
    stream.avail_in = inFile.readsome(inBuffer, sizeof(inBuffer));
    stream.next_in = reinterpret_cast<Bytef*>(inBuffer);

    do {
        stream.avail_out = sizeof(outBuffer);
        stream.next_out = reinterpret_cast<Bytef*>(outBuffer);
        inflate(&stream, Z_NO_FLUSH);
        outFile.write(outBuffer, sizeof(outBuffer) - stream.avail_out);
    } while (stream.avail_out == 0);

    inflateEnd(&stream);
    inFile.close();
    outFile.close();

    return true;
}

int main() {
    std::string sourceFile = "input.txt";
    std::string compressedFile = "compressed.zlib";
    std::string decompressedFile = "decompressed.txt";

    // 压缩文件
    if (compressFile(sourceFile, compressedFile)) {
        std::cout << "File compressed successfully." << std::endl;
    } else {
        std::cout << "Failed to compress file." << std::endl;
    }

    // 解压缩文件
    if (decompressFile(compressedFile, decompressedFile)) {
        std::cout << "File decompressed successfully." << std::endl;
    } else {
        std::cout << "Failed to decompress file." << std::endl;
    }

    return 0;
}

这个示例代码演示了如何使用zlib库进行文件的压缩和解压缩。你可以根据自己的需求修改输入输出文件的路径和名称。在压缩文件时，使用`deflate`函数将输入数据压缩，并将压缩后的数据写入输出文件。在解压缩文件时，使用`inflate`函数将压缩数据解压缩，并将解压缩后的数据写入输出文件。