bzip2.hpp

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// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
// (C) Copyright 2003-2007 Jonathan Turkanis
// 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.

// Note: custom allocators are not supported on VC6, since that compiler
// had trouble finding the function zlib_base::do_init.

#ifndef BOOST_IOSTREAMS_BZIP2_HPP_INCLUDED
#define BOOST_IOSTREAMS_BZIP2_HPP_INCLUDED

#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif
                   
#include <cassert>                            
#include <memory>            // allocator.
#include <new>               // bad_alloc.
#include <boost/config.hpp>  // MSVC, STATIC_CONSTANT, DEDUCED_TYPENAME, DINKUM.
#include <boost/detail/workaround.hpp>
#include <boost/iostreams/constants.hpp>   // buffer size.
#include <boost/iostreams/detail/config/auto_link.hpp>
#include <boost/iostreams/detail/config/bzip2.hpp>
#include <boost/iostreams/detail/config/dyn_link.hpp>
#include <boost/iostreams/detail/config/wide_streams.hpp>
#include <boost/iostreams/detail/ios.hpp>  // failure, streamsize.
#include <boost/iostreams/filter/symmetric.hpp>               
#include <boost/iostreams/pipeline.hpp>       
#include <boost/type_traits/is_same.hpp>     

// Must come last.
#ifdef BOOST_MSVC
# pragma warning(push)
# pragma warning(disable:4251 4231 4660)
#endif
#include <boost/config/abi_prefix.hpp>           

// Temporary fix.
#undef small

namespace boost { namespace iostreams {

namespace bzip2 {

                    // Typedefs.

typedef void* (*alloc_func)(void*, int, int);
typedef void (*free_func)(void*, void*);

                    // Status codes

BOOST_IOSTREAMS_DECL extern const int ok;
BOOST_IOSTREAMS_DECL extern const int run_ok;
BOOST_IOSTREAMS_DECL extern const int flush_ok;
BOOST_IOSTREAMS_DECL extern const int finish_ok;
BOOST_IOSTREAMS_DECL extern const int stream_end;    
BOOST_IOSTREAMS_DECL extern const int sequence_error;
BOOST_IOSTREAMS_DECL extern const int param_error;
BOOST_IOSTREAMS_DECL extern const int mem_error;
BOOST_IOSTREAMS_DECL extern const int data_error;
BOOST_IOSTREAMS_DECL extern const int data_error_magic;
BOOST_IOSTREAMS_DECL extern const int io_error;
BOOST_IOSTREAMS_DECL extern const int unexpected_eof;
BOOST_IOSTREAMS_DECL extern const int outbuff_full;
BOOST_IOSTREAMS_DECL extern const int config_error;

                    // Action codes

BOOST_IOSTREAMS_DECL extern const int finish;
BOOST_IOSTREAMS_DECL extern const int run;

                    // Default values

const int default_block_size   = 9;
const int default_work_factor  = 30;
const bool default_small       = false;

} // End namespace bzip2. 

//
// Class name: bzip2_params.
// Description: Encapsulates the parameters passed to deflateInit2
//      to customize compression.
//
struct bzip2_params {

    // Non-explicit constructor for compression.
    bzip2_params( int block_size   = bzip2::default_block_size,
                  int work_factor  = bzip2::default_work_factor )
        : block_size(block_size), work_factor(work_factor)
        { }

    // Constructor for decompression.
    bzip2_params(bool small)
        : small(small), work_factor(0)
        { }

    union {
        int   block_size;    // For compression.
        bool  small;         // For decompression.
    };
    int       work_factor;
};

//
// Class name: bzip2_error.
// Description: Subclass of std::ios_base::failure thrown to indicate
//     bzip2 errors other than out-of-memory conditions.
//
class BOOST_IOSTREAMS_DECL bzip2_error : public BOOST_IOSTREAMS_FAILURE {
public:
    explicit bzip2_error(int error);
    int error() const { return error_; }
    static void check(int error);
private:
    int error_;
};

namespace detail {

template<typename Alloc>
struct bzip2_allocator_traits {
#ifndef BOOST_NO_STD_ALLOCATOR
    typedef typename Alloc::template rebind<char>::other type;
#else
    typedef std::allocator<char> type;
#endif
};

template< typename Alloc,
          typename Base = // VC6 workaround (C2516)
              BOOST_DEDUCED_TYPENAME bzip2_allocator_traits<Alloc>::type >
struct bzip2_allocator : private Base {
private:
    typedef typename Base::size_type size_type;
public:
    BOOST_STATIC_CONSTANT(bool, custom = 
        (!is_same<std::allocator<char>, Base>::value));
    typedef typename bzip2_allocator_traits<Alloc>::type allocator_type;
    static void* allocate(void* self, int items, int size);
    static void deallocate(void* self, void* address);
};

class BOOST_IOSTREAMS_DECL bzip2_base  { 
public:
    typedef char char_type;
protected:
    bzip2_base(const bzip2_params& params);
    ~bzip2_base();
    bzip2_params& params() { return params_; }
    bool& ready() { return ready_; }
    template<typename Alloc> 
    void init( bool compress,
               bzip2_allocator<Alloc>& alloc )
        {
            bool custom = bzip2_allocator<Alloc>::custom;
            do_init( compress,
                     #if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
                         custom ? bzip2_allocator<Alloc>::allocate : 0,
                         custom ? bzip2_allocator<Alloc>::deallocate : 0,
                     #endif
                     custom ? &alloc : 0 );
        }
    void before( const char*& src_begin, const char* src_end,
                 char*& dest_begin, char* dest_end );
    void after(const char*& src_begin, char*& dest_begin);
    int compress(int action);
    int decompress();
    void end(bool compress);
private:
    void do_init( bool compress, 
                  #if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
                      bzip2::alloc_func, 
                      bzip2::free_func, 
                  #endif
                  void* derived );
    bzip2_params  params_;
    void*         stream_; // Actual type: bz_stream*.
    bool          ready_;
};

//
// Template name: bzip2_compressor_impl
// Description: Model of SymmetricFilter implementing compression by
//      delegating to the libbzip2 function BZ_bzCompress.
//
template<typename Alloc = std::allocator<char> >
class bzip2_compressor_impl 
    : public bzip2_base, 
      #if BOOST_WORKAROUND(__BORLANDC__, < 0x600)
          public
      #endif
      bzip2_allocator<Alloc> 
{
public: 
    bzip2_compressor_impl(const bzip2_params&);
    bool filter( const char*& src_begin, const char* src_end,
                 char*& dest_begin, char* dest_end, bool flush );
    void close();
private:
    void init();
};

//
// Template name: bzip2_compressor
// Description: Model of SymmetricFilter implementing decompression by
//      delegating to the libbzip2 function BZ_bzDecompress.
//
template<typename Alloc = std::allocator<char> >
class bzip2_decompressor_impl 
    : public bzip2_base, 
      #if BOOST_WORKAROUND(__BORLANDC__, < 0x600)
          public
      #endif
      bzip2_allocator<Alloc> 
{ 
public:
    bzip2_decompressor_impl(bool small = bzip2::default_small);
    bool filter( const char*& begin_in, const char* end_in,
                 char*& begin_out, char* end_out, bool flush );
    void close();
private:
    void init();
    bool eof_; // Guard to make sure filter() isn't called after it returns false.
};

} // End namespace detail.

//
// Template name: bzip2_compressor
// Description: Model of InputFilter and OutputFilter implementing
//      compression using libbzip2.
//
template<typename Alloc = std::allocator<char> >
struct basic_bzip2_compressor 
    : symmetric_filter<detail::bzip2_compressor_impl<Alloc>, Alloc> 
{
private:
    typedef detail::bzip2_compressor_impl<Alloc>        impl_type;
    typedef symmetric_filter<impl_type, Alloc>  base_type;
public:
    typedef typename base_type::char_type               char_type;
    typedef typename base_type::category                category;
    basic_bzip2_compressor( const bzip2_params& = bzip2::default_block_size, 
                            int buffer_size =  default_device_buffer_size );
};
BOOST_IOSTREAMS_PIPABLE(basic_bzip2_compressor, 1)

typedef basic_bzip2_compressor<> bzip2_compressor;

//
// Template name: bzip2_decompressor
// Description: Model of InputFilter and OutputFilter implementing
//      decompression using libbzip2.
//
template<typename Alloc = std::allocator<char> >
struct basic_bzip2_decompressor 
    : symmetric_filter<detail::bzip2_decompressor_impl<Alloc>, Alloc> 
{
private:
    typedef detail::bzip2_decompressor_impl<Alloc>      impl_type;
    typedef symmetric_filter<impl_type, Alloc>  base_type;
public:
    typedef typename base_type::char_type               char_type;
    typedef typename base_type::category                category;
    basic_bzip2_decompressor( bool small = bzip2::default_small,
                              int buffer_size = default_device_buffer_size );
};
BOOST_IOSTREAMS_PIPABLE(basic_bzip2_decompressor, 1)

typedef basic_bzip2_decompressor<> bzip2_decompressor;

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

//------------------Implementation of bzip2_allocator-------------------------//

namespace detail {

template<typename Alloc, typename Base>
void* bzip2_allocator<Alloc, Base>::allocate(void* self, int items, int size)
{ 
    size_type len = items * size;
    char* ptr = 
        static_cast<allocator_type*>(self)->allocate
            (len + sizeof(size_type)
            #if BOOST_WORKAROUND(BOOST_DINKUMWARE_STDLIB, == 1)
                , (char*)0
            #endif
            );
    *reinterpret_cast<size_type*>(ptr) = len;
    return ptr + sizeof(size_type);
}

template<typename Alloc, typename Base>
void bzip2_allocator<Alloc, Base>::deallocate(void* self, void* address)
{ 
    char* ptr = reinterpret_cast<char*>(address) - sizeof(size_type);
    size_type len = *reinterpret_cast<size_type*>(ptr) + sizeof(size_type);
    static_cast<allocator_type*>(self)->deallocate(ptr, len); 
}

//------------------Implementation of bzip2_compressor_impl-------------------//

template<typename Alloc>
bzip2_compressor_impl<Alloc>::bzip2_compressor_impl(const bzip2_params& p)
    : bzip2_base(p) { }

template<typename Alloc>
bool bzip2_compressor_impl<Alloc>::filter
    ( const char*& src_begin, const char* src_end,
      char*& dest_begin, char* dest_end, bool flush )
{
    if (!ready()) init();
    before(src_begin, src_end, dest_begin, dest_end);
    int result = compress(flush ? bzip2::finish : bzip2::run);
    after(src_begin, dest_begin);
    bzip2_error::check(result);
    return result != bzip2::stream_end;
}

template<typename Alloc>
void bzip2_compressor_impl<Alloc>::close() 
{ 
    end(true); 
}

template<typename Alloc>
inline void bzip2_compressor_impl<Alloc>::init() 
{ bzip2_base::init(true, static_cast<bzip2_allocator<Alloc>&>(*this)); }

//------------------Implementation of bzip2_decompressor_impl-----------------//

template<typename Alloc>
bzip2_decompressor_impl<Alloc>::bzip2_decompressor_impl(bool small)
    : bzip2_base(bzip2_params(small)), eof_(false) { }

template<typename Alloc>
bool bzip2_decompressor_impl<Alloc>::filter
    ( const char*& src_begin, const char* src_end,
      char*& dest_begin, char* dest_end, bool /* flush */ )
{
    if (!ready()) 
        init();
    if (eof_) 
        return false;
    before(src_begin, src_end, dest_begin, dest_end);
    int result = decompress();
    after(src_begin, dest_begin);
    bzip2_error::check(result);
    return !(eof_ = result == bzip2::stream_end); 
}

template<typename Alloc>
void bzip2_decompressor_impl<Alloc>::close() 
{ 
    try {
        end(false);
    } catch (...) { 
        eof_ = false; 
        throw;
    }
    eof_ = false;
}

template<typename Alloc>
inline void bzip2_decompressor_impl<Alloc>::init()
{ bzip2_base::init(false, static_cast<bzip2_allocator<Alloc>&>(*this)); }
} // End namespace detail.

//------------------Implementation of bzip2_decompressor----------------------//

template<typename Alloc>
basic_bzip2_compressor<Alloc>::basic_bzip2_compressor
        (const bzip2_params& p, int buffer_size) 
    : base_type(buffer_size, p) 
    { }

//------------------Implementation of bzip2_decompressor----------------------//

template<typename Alloc>
basic_bzip2_decompressor<Alloc>::basic_bzip2_decompressor
        (bool small, int buffer_size) 
    : base_type(buffer_size, small)
    { }

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

} } // End namespaces iostreams, boost.

#include <boost/config/abi_suffix.hpp> // Pops abi_suffix.hpp pragmas.
#ifdef BOOST_MSVC
# pragma warning(pop)
#endif

#endif // #ifndef BOOST_IOSTREAMS_BZIP2_HPP_INCLUDED