用c++编写lzma的算法代码
时间: 2024-06-08 21:11:44 浏览: 10
以下是使用C++编写LZMA算法的示例代码:
```c++
#include <lzma.h>
#include <iostream>
#include <string>
#include <vector>
// 压缩函数
std::vector<uint8_t> compress_lzma(const uint8_t* data, size_t size) {
std::vector<uint8_t> compressed_data;
// 初始化LZMA编码器
lzma_stream strm = LZMA_STREAM_INIT;
lzma_ret ret = lzma_easy_encoder(&strm, LZMA_CHECK_CRC64, LZMA_PRESET_DEFAULT);
if (ret != LZMA_OK) {
std::cerr << "LZMA encoder initialization failed with error code " << ret << std::endl;
return compressed_data;
}
// 压缩数据
const size_t bufsize = 1024 * 1024;
uint8_t* inbuf = const_cast<uint8_t*>(data);
uint8_t* outbuf = new uint8_t[bufsize];
strm.avail_in = size;
strm.next_in = inbuf;
do {
strm.avail_out = bufsize;
strm.next_out = outbuf;
ret = lzma_code(&strm, LZMA_RUN);
if (ret != LZMA_OK && ret != LZMA_STREAM_END) {
std::cerr << "LZMA compression failed with error code " << ret << std::endl;
delete[] outbuf;
return compressed_data;
}
size_t compressed_size = bufsize - strm.avail_out;
for (size_t i = 0; i < compressed_size; ++i) {
compressed_data.push_back(outbuf[i]);
}
} while (strm.avail_out == 0);
delete[] outbuf;
// 结束LZMA编码器
lzma_end(&strm);
return compressed_data;
}
// 解压函数
std::vector<uint8_t> decompress_lzma(const uint8_t* data, size_t size) {
std::vector<uint8_t> decompressed_data;
// 初始化LZMA解码器
lzma_stream strm = LZMA_STREAM_INIT;
lzma_ret ret = lzma_stream_decoder(&strm, UINT64_MAX, 0);
if (ret != LZMA_OK) {
std::cerr << "LZMA decoder initialization failed with error code " << ret << std::endl;
return decompressed_data;
}
// 解压数据
const size_t bufsize = 1024 * 1024;
uint8_t* inbuf = const_cast<uint8_t*>(data);
uint8_t* outbuf = new uint8_t[bufsize];
strm.avail_in = size;
strm.next_in = inbuf;
do {
strm.avail_out = bufsize;
strm.next_out = outbuf;
ret = lzma_code(&strm, LZMA_RUN);
if (ret != LZMA_OK && ret != LZMA_STREAM_END) {
std::cerr << "LZMA decompression failed with error code " << ret << std::endl;
delete[] outbuf;
return decompressed_data;
}
size_t decompressed_size = bufsize - strm.avail_out;
for (size_t i = 0; i < decompressed_size; ++i) {
decompressed_data.push_back(outbuf[i]);
}
} while (strm.avail_out == 0);
delete[] outbuf;
// 结束LZMA解码器
lzma_end(&strm);
return decompressed_data;
}
int main() {
// 测试数据
std::string test_string = "This is a test string for LZMA compression and decompression.";
std::vector<uint8_t> test_data(test_string.begin(), test_string.end());
// 压缩
std::vector<uint8_t> compressed_data = compress_lzma(test_data.data(), test_data.size());
std::cout << "Compressed size: " << compressed_data.size() << std::endl;
// 解压
std::vector<uint8_t> decompressed_data = decompress_lzma(compressed_data.data(), compressed_data.size());
std::string decompressed_string(decompressed_data.begin(), decompressed_data.end());
std::cout << "Decompressed string: " << decompressed_string << std::endl;
return 0;
}
```
在这个示例代码中,我们使用了LZMA SDK提供的函数来初始化LZMA编码器和解码器,并使用`lzma_code()`函数来压缩和解压数据。该代码使用`std::vector<uint8_t>`来存储二进制数据。