lzmaテスト

2325 ワード

#include "stdafx.h"
#include 
#include "lzma.h"

#pragma comment(lib, "lzma")

std::string CompressWithLzma(const std::string& in, int level)
{
    std::string result;
    result.resize(in.size() + (in.size() >> 2) + 128);
    size_t out_pos = 0;

    if (LZMA_OK != lzma_easy_buffer_encode(
            level, LZMA_CHECK_CRC32, NULL,
            reinterpret_cast(const_cast(in.data())), in.size(),
            reinterpret_cast(&result[0]), &out_pos, result.size()))
        abort();

    result.resize(out_pos);
    return result;
}

std::string DecompressWithLzma(const std::string& in)
{
    static const size_t kMemLimit = 1 << 30;  // 1 GB.
    lzma_stream strm = LZMA_STREAM_INIT;
    std::string result;
    result.resize(8192);
    size_t result_used = 0;
    lzma_ret ret;
    ret = lzma_stream_decoder(&strm, kMemLimit, LZMA_CONCATENATED);

    if (ret != LZMA_OK)
        abort();

    size_t avail0 = result.size();
    strm.next_in = reinterpret_cast(in.data());
    strm.avail_in = in.size();
    strm.next_out = reinterpret_cast(&result[0]);
    strm.avail_out = avail0;

    while (true) {
        ret = lzma_code(&strm, strm.avail_in == 0 ? LZMA_FINISH : LZMA_RUN);

        if (ret == LZMA_STREAM_END) {
            result_used += avail0 - strm.avail_out;

            if (0 != strm.avail_in)  // Guaranteed by lzma_stream_decoder().
                abort();

            result.resize(result_used);
            lzma_end(&strm);
            return result;
        }

        if (ret != LZMA_OK)
            abort();

        if (strm.avail_out == 0) {
            result_used += avail0 - strm.avail_out;
            result.resize(result.size() << 1);
            strm.next_out = reinterpret_cast(&result[0] + result_used);
            strm.avail_out = avail0 = result.size() - result_used;
        }
    }
}

int _tmain(int argc, _TCHAR* argv[])
{
    const std::string szSampleString = "This is a Test String!!";
    std::string szCompressed = CompressWithLzma(szSampleString, 0);
    std::string szDeCompressed = DecompressWithLzma(szCompressed);
    return 0;
}