Boost C++ Libraries

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This is the documentation for a snapshot of the develop branch, built from commit 69ea439003.

libs/iostreams/src/lzma.cpp

// (C) Copyright Milan Svoboda 2008.
// Originally developed under the fusecompress project.
// Based on bzip2.cpp by:
// (C) Copyright Jonathan Turkanis 2003.
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)

// See http://www.boost.org/libs/iostreams for documentation.

// Define BOOST_IOSTREAMS_SOURCE so that <boost/iostreams/detail/config.hpp>
// knows that we are building the library (possibly exporting code), rather
// than using it (possibly importing code).
#define BOOST_IOSTREAMS_SOURCE

#include <lzma.h>

#include <boost/throw_exception.hpp>
#include <boost/iostreams/detail/config/dyn_link.hpp>
#include <boost/iostreams/filter/lzma.hpp>


#ifndef BOOST_IOSTREAMS_LZMA_NO_MULTITHREADED
    #if LZMA_VERSION < 50020002
        #define BOOST_IOSTREAMS_LZMA_NO_MULTITHREADED
    #endif
#endif

namespace boost { namespace iostreams {

namespace lzma {

                    // Compression levels

const uint32_t no_compression       = 0;
const uint32_t best_speed           = 1;
const uint32_t best_compression     = 9;
const uint32_t default_compression  = 2;

                    // Status codes

const int okay                 = LZMA_OK;
const int stream_end           = LZMA_STREAM_END;
const int unsupported_check    = LZMA_UNSUPPORTED_CHECK;
const int mem_error            = LZMA_MEM_ERROR;
const int options_error        = LZMA_OPTIONS_ERROR;
const int data_error           = LZMA_DATA_ERROR;
const int buf_error            = LZMA_BUF_ERROR;
const int prog_error           = LZMA_PROG_ERROR;

                    // Flush codes

const int finish               = LZMA_FINISH;
const int full_flush           = LZMA_FULL_FLUSH;
const int sync_flush           = LZMA_SYNC_FLUSH;
const int run                  = LZMA_RUN;

                    // Code for current OS

} // End namespace lzma.

//------------------Implementation of lzma_error------------------------------//

lzma_error::lzma_error(int error)
    : BOOST_IOSTREAMS_FAILURE("lzma error"), error_(error)
    { }

void lzma_error::check BOOST_PREVENT_MACRO_SUBSTITUTION(int error)
{
    switch (error) {
    case LZMA_OK:
    case LZMA_STREAM_END:
        return;
    case LZMA_MEM_ERROR:
        boost::throw_exception(std::bad_alloc());
    default:
        boost::throw_exception(lzma_error(error));
    }
}

//------------------Implementation of lzma_base-------------------------------//

namespace detail {

lzma_base::lzma_base()
    : stream_(new lzma_stream), level_(lzma::default_compression), threads_(1)
    { }

lzma_base::~lzma_base() { delete static_cast<lzma_stream*>(stream_); }

void lzma_base::before( const char*& src_begin, const char* src_end,
                        char*& dest_begin, char* dest_end )
{
    lzma_stream* s = static_cast<lzma_stream*>(stream_);
    s->next_in = reinterpret_cast<uint8_t*>(const_cast<char*>(src_begin));
    s->avail_in = static_cast<size_t>(src_end - src_begin);
    s->next_out = reinterpret_cast<uint8_t*>(dest_begin);
    s->avail_out= static_cast<size_t>(dest_end - dest_begin);
}

void lzma_base::after(const char*& src_begin, char*& dest_begin, bool)
{
    lzma_stream* s = static_cast<lzma_stream*>(stream_);
    src_begin = const_cast<const char*>(reinterpret_cast<const char*>(s->next_in));
    dest_begin = reinterpret_cast<char*>(s->next_out);
}

int lzma_base::deflate(int action)
{
    return lzma_code(static_cast<lzma_stream*>(stream_), static_cast<lzma_action>(action));
}

int lzma_base::inflate(int action)
{
    return lzma_code(static_cast<lzma_stream*>(stream_), static_cast<lzma_action>(action));
}

void lzma_base::reset(bool compress, bool realloc)
{
    lzma_stream* s = static_cast<lzma_stream*>(stream_);
    lzma_end(s);
    if (realloc)
    {
        init_stream(compress);
    }
}

void lzma_base::do_init
    ( const lzma_params& p, bool compress,
      lzma::alloc_func, lzma::free_func,
      void* )
{

    level_ = p.level;
    threads_ = p.threads;

#ifndef BOOST_IOSTREAMS_LZMA_NO_MULTITHREADED
    if (threads_ == 0) {
        threads_ = lzma_cputhreads();
    }
#endif

    init_stream(compress);
}

void lzma_base::init_stream(bool compress)
{
    lzma_stream* s = static_cast<lzma_stream*>(stream_);

    memset(s, 0, sizeof(*s));

#ifndef BOOST_IOSTREAMS_LZMA_NO_MULTITHREADED
    const lzma_mt opt = { 0, threads_, 0, 1000, level_, NULL, LZMA_CHECK_CRC32 };
#endif

    lzma_error::check BOOST_PREVENT_MACRO_SUBSTITUTION(
        compress ?
#ifdef BOOST_IOSTREAMS_LZMA_NO_MULTITHREADED
            lzma_easy_encoder(s, level_, LZMA_CHECK_CRC32) :
#else
            lzma_stream_encoder_mt(s, &opt) :
#endif
            lzma_stream_decoder(s, 100 * 1024 * 1024, LZMA_CONCATENATED)
    );
}


} // End namespace detail.

//----------------------------------------------------------------------------//

} } // End namespaces iostreams, boost.