c++ zlib 解压 2MB的gzip字符串

对于2MB大小的gzip字符串，可以使用上面的代码进行解压，只需要将缓冲区的大小调整为2MB即可。修改代码如下：

#include <iostream>
#include <fstream>
#include <sstream>
#include <cstring>
#include <stdexcept>
#include <zlib.h>

std::string gzip_decompress(const std::string& compressed_string) {
    const size_t BUFFER_SIZE = 2 * 1024 * 1024;  // 修改为2MB
    char buffer[BUFFER_SIZE];
    std::stringstream uncompressed_stream;
    z_stream zs;    
    memset(&zs, 0, sizeof(zs));

    if (inflateInit2(&zs, 16 + MAX_WBITS) != Z_OK) {
        throw std::runtime_error("inflateInit2 failed while decompressing.");
    }

    zs.next_in = (Bytef*)compressed_string.data();
    zs.avail_in = compressed_string.size();

    int ret;
    do {
        zs.next_out = reinterpret_cast<Bytef*>(buffer);
        zs.avail_out = BUFFER_SIZE;

        ret = inflate(&zs, 0);

        if (uncompressed_stream.tellp() < 0) {
            throw std::runtime_error("uncompressed stream error while decompressing.");
        }

        uncompressed_stream.write(buffer, BUFFER_SIZE - zs.avail_out);

    } while (ret == Z_OK);

    inflateEnd(&zs);

    if (ret != Z_STREAM_END) {
        throw std::runtime_error("corrupted compressed string while decompressing.");
    }

    return uncompressed_stream.str();
}

int main() {
    std::ifstream input_file("compressed.gz", std::ios::in | std::ios::binary);
    std::stringstream compressed_stream;
    compressed_stream << input_file.rdbuf();
    std::string compressed_string = compressed_stream.str();

    std::string uncompressed_string = gzip_decompress(compressed_string);

    std::cout << uncompressed_string << std::endl;

    return 0;
}

在上面的代码中，我们将缓冲区的大小修改为2MB，这样就可以处理2MB大小的gzip字符串了。