C语言中怎样处理压缩数据 C语言zlib库集成与压缩解压示例

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <zlib.h>

#define CHUNK 16384 // 每次处理的数据块大小

/* 压缩数据 */
int compress_data(Bytef *data, uLong data_len, Bytef *compressed_data, uLong *compressed_len) {
    z_stream strm;
    int ret;

    strm.zalloc = Z_NULL;
    strm.zfree = Z_NULL;
    strm.opaque = Z_NULL;
    strm.avail_in = data_len;
    strm.next_in = data;

    ret = deflateInit(&strm, Z_BEST_COMPRESSION); // 初始化压缩，选择最佳压缩级别
    if (ret != Z_OK)
        return ret;

    strm.avail_out = *compressed_len;
    strm.next_out = compressed_data;

    ret = deflate(&strm, Z_FINISH); // 执行压缩，直到输入数据全部处理完毕
    if (ret != Z_STREAM_END) {
        deflateEnd(&strm);
        return ret == Z_OK ? Z_BUF_ERROR : ret; // 如果缓冲区不足，返回错误
    }

    *compressed_len = strm.total_out; // 更新压缩后的数据长度

    deflateEnd(&strm); // 清理资源
    return Z_OK;
}

/* 解压缩数据 */
int decompress_data(Bytef *compressed_data, uLong compressed_len, Bytef *decompressed_data, uLong *decompressed_len) {
    z_stream strm;
    int ret;

    strm.zalloc = Z_NULL;
    strm.zfree = Z_NULL;
    strm.opaque = Z_NULL;
    strm.avail_in = compressed_len;
    strm.next_in = compressed_data;

    ret = inflateInit(&strm); // 初始化解压缩
    if (ret != Z_OK)
        return ret;

    strm.avail_out = *decompressed_len;
    strm.next_out = decompressed_data;

    ret = inflate(&strm, Z_FINISH); // 执行解压缩，直到输入数据全部处理完毕
    if (ret != Z_STREAM_END) {
        inflateEnd(&strm);
        return ret == Z_OK ? Z_BUF_ERROR : ret; // 如果缓冲区不足，返回错误
    }

    *decompressed_len = strm.total_out; // 更新解压缩后的数据长度

    inflateEnd(&strm); // 清理资源
    return Z_OK;
}

int main() {
    char original_data[] = "This is a test string to be compressed and decompressed using zlib.";
    uLong original_len = strlen(original_data) + 1; // 包括 null 终止符

    uLong compressed_len = compressBound(original_len); // 预估压缩后的最大长度
    Bytef *compressed_data = (Bytef*)malloc(compressed_len);
    if (!compressed_data) {
        fprintf(stderr, "Failed to allocate memory for compressed data.\n");
        return 1;
    }

    uLong decompressed_len = original_len;
    Bytef *decompressed_data = (Bytef*)malloc(decompressed_len);
    if (!decompressed_data) {
        fprintf(stderr, "Failed to allocate memory for decompressed data.\n");
        free(compressed_data);
        return 1;
    }

    int ret = compress_data((Bytef*)original_data, original_len, compressed_data, &compressed_len);
    if (ret != Z_OK) {
        fprintf(stderr, "Compression failed: %d\n", ret);
        free(compressed_data);
        free(decompressed_data);
        return 1;
    }

    printf("Original size: %lu\n", original_len);
    printf("Compressed size: %lu\n", compressed_len);

    ret = decompress_data(compressed_data, compressed_len, decompressed_data, &decompressed_len);
    if (ret != Z_OK) {
        fprintf(stderr, "Decompression failed: %d\n", ret);
        free(compressed_data);
        free(decompressed_data);
        return 1;
    }

    printf("Decompressed size: %lu\n", decompressed_len);
    printf("Decompressed data: %s\n", (char*)decompressed_data);

    free(compressed_data);
    free(decompressed_data);

    return 0;
}