如何在C++中实现buffer的压缩解压功能

在C++中实现buffer的压缩和解压功能可以使用一些开源的压缩库，比如zlib、zstd、LZ4等。这些库提供了压缩和解压缩数据的函数，可以很方便地在C++代码中调用。

以下是一个使用zlib库实现buffer压缩和解压缩的示例代码：

#include <iostream> #include <zlib.h>  // 压缩函数 void compressData(const char* input, size_t inputSize, char* output, size_t& outputSize) {     z_stream stream;     stream.zalloc = Z_NULL;     stream.zfree = Z_NULL;     stream.opaque = Z_NULL;      if(deflateInit(&stream, Z_BEST_COMPRESSION) != Z_OK)     {         return;     }      stream.avail_in = inputSize;     stream.next_in = (Bytef*)input;     stream.avail_out = outputSize;     stream.next_out = (Bytef*)output;      int ret = deflate(&stream, Z_FINISH);     if(ret != Z_STREAM_END)     {         deflateEnd(&stream);         return;     }      deflateEnd(&stream);     outputSize = stream.total_out; }  // 解压函数 void decompressData(const char* input, size_t inputSize, char* output, size_t& outputSize) {     z_stream stream;     stream.zalloc = Z_NULL;     stream.zfree = Z_NULL;     stream.opaque = Z_NULL;      if(inflateInit(&stream) != Z_OK)     {         return;     }      stream.avail_in = inputSize;     stream.next_in = (Bytef*)input;     stream.avail_out = outputSize;     stream.next_out = (Bytef*)output;      int ret = inflate(&stream, Z_FINISH);     if(ret != Z_STREAM_END)     {         inflateEnd(&stream);         return;     }      inflateEnd(&stream);     outputSize = stream.total_out; }  int main() {     const char* input = "Hello, world!";     size_t inputSize = strlen(input);     size_t compressedSize = compressBound(inputSize);     char* compressedData = new char[compressedSize];      compressData(input, inputSize, compressedData, compressedSize);      std::cout << "Compressed data size: " << compressedSize << std::endl;      size_t decompressedSize = inputSize;     char* decompressedData = new char[decompressedSize];      decompressData(compressedData, compressedSize, decompressedData, decompressedSize);      std::cout << "Decompressed data: " << decompressedData << std::endl;      delete[] compressedData;     delete[] decompressedData;      return 0; } 

在上面的示例代码中，我们使用zlib库实现了buffer的压缩和解压缩功能。在压缩函数中，我们使用deflateInit()函数初始化z_stream结构体，然后调用deflate()函数进行数据压缩；在解压函数中，我们使用inflateInit()函数初始化z_stream结构体，然后调用inflate()函数进行数据解压。压缩后的数据可以通过compressBound()函数获取压缩后的大小。