osga_archive.cpp

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#include <osg/Notify>
#include <osg/Endian>

#include <osgDB/Registry>
#include <osgDB/FileNameUtils>

#include "OSGA_Archive.h"

using namespace osgDB;

/*
Functions to convert between
    std::streampos ( typedef'ed as iostream::pos_type 
              used as seekp,seekg argument and tellp,tellg return value )
and 
    OSGA_Archive::pos_type (64 bit file position index)

Purpose:
    To allow using OSGA files larger than 4GiB in Windows.

    std::streampos is used as argument to iostreams seekp and seekg methods
    and is returned as result from iostream tellp and tellg methods.

    std::streampos can be implicitly cast from/to std::streamoff as 
    std::streampos class defines appropriate constructor and cast operator.

    Since std::streamoff is usually defined as simple int, 
    it is possible to call seekp( ), seekg( ) with int argument and
    assign tellp(), tellg() result to int type.

    But this implicit methods fail when std::streamoff is 32 bit and 
    std::streampos actually points past 32 bit addressable range (2 GiB).

    Even if std::streamoff is 32 bit and incapable of representing 64 bit file
    positions, original std::streampos may be prefectly able to handle them.
   
    But, when such situation occurs more elaborate conversion methods from/to   
    std::streampos are needed. Functions below employ such methods. 
    
    I made this fix for use with 32 bit Windows OSG. Acutally this 
    solution is not dependent on OS but standard C++ library. 
    Microsoft SDKs always use some version of Dinkumware libs. 

    Practically this tweak is made for Dinkumware C++ libs. I hope it can 
    be easily extended to other 32bit systems supporting 64bit files, provided
    their std::streampos implementations are similar.

    I based my solution on a small portion of boost iostreams code.
    For additional reference look at: 
        http://boost.org/boost/iostreams/positioning.hpp
*/

/* 
    Recognize Dinkumware std C++ lib implementation. Its used by Microsoft, 
    but method is more generic - should work in all Dinkumware environments.

    Complex condition below was taken from 
        http://boost.org/boost/iostreams/positioning.hpp

    Great thanks to J.Tukanis and G. Sylvester-Bradley for figuring it out.
*/
#if ((defined(_YVALS) && !defined(__IBMCPP__)) || defined(_CPPLIB_VER)) && \
     !defined(__SGI_STL_PORT) && !defined(_STLPORT_VERSION) \
     && !defined(__QNX__)

inline std::streampos STREAM_POS( const OSGA_Archive::pos_type pos )
{ 
    return std::streampos( std::mbstate_t(), pos );
}

inline OSGA_Archive::pos_type ARCHIVE_POS( const std::streampos & pos )
{ 
#if defined(_CPPLIB_VER)//newer Dinkumware(eg: one included with VC++ 2003,2005)
    fpos_t position = pos.seekpos();
#else // older Dinkumware (eg: one included in Win Server 2003 Platform SDK )
    fpos_t position = pos.get_fpos_t();
#endif
    std::streamoff offset = pos.operator std::streamoff( ) - _FPOSOFF( position );

    return OSGA_Archive::pos_type( position + offset );
}
#else // non Dinkumware std C++ lib implementations 
// do the old school streampos <-> streamoff casts
inline std::streampos STREAM_POS( const OSGA_Archive::pos_type pos )
{ 
    return std::streampos( pos );
}

inline OSGA_Archive::pos_type ARCHIVE_POS( const std::streampos & pos )
{ 
    return OSGA_Archive::pos_type( pos );
}
#endif // Dinkumware std C++ lib 
////////////////////////////////////////////////////////////////////////////////
float OSGA_Archive::s_currentSupportedVersion = 0.0;
const unsigned int ENDIAN_TEST_NUMBER = 0x00000001;

OSGA_Archive::IndexBlock::IndexBlock(unsigned int blockSize):
    _requiresWrite(false),
    _filePosition(0),
    _blockSize(0),
    _filePositionNextIndexBlock(0),
    _offsetOfNextAvailableSpace(0),
    _data(0)
{
    allocateData(blockSize);
}

OSGA_Archive::IndexBlock::~IndexBlock()
{
    delete [] _data;
}

void OSGA_Archive::IndexBlock::allocateData(unsigned int blockSize)
{
    _data = (blockSize!=0) ? new char[blockSize]  : 0;
    if (_data)
    {
        _blockSize = blockSize;
        
        // initialize the array
        char* end = _data + _blockSize;
        for(char* ptr=_data; ptr < end; ++ptr) *ptr = 0;
    }
    else
    {
        _blockSize = 0;
    }
}

OSGA_Archive::IndexBlock* OSGA_Archive::IndexBlock::read(std::istream& in, bool doEndianSwap)
{
    if (!in) return 0;

    osg::ref_ptr<IndexBlock> indexBlock = new IndexBlock;
    indexBlock->_filePosition = ARCHIVE_POS( in.tellg() );
    in.read(reinterpret_cast<char*>(&indexBlock->_blockSize), sizeof(indexBlock->_blockSize));
    in.read(reinterpret_cast<char*>(&indexBlock->_filePositionNextIndexBlock), sizeof(indexBlock->_filePositionNextIndexBlock));
    in.read(reinterpret_cast<char*>(&indexBlock->_offsetOfNextAvailableSpace), sizeof(indexBlock-> _offsetOfNextAvailableSpace));
    
    if (doEndianSwap)
    {
        osg::swapBytes(reinterpret_cast<char*>(&indexBlock->_blockSize), sizeof(indexBlock->_blockSize));
        osg::swapBytes(reinterpret_cast<char*>(&indexBlock->_filePositionNextIndexBlock), sizeof(indexBlock->_filePositionNextIndexBlock));
        osg::swapBytes(reinterpret_cast<char*>(&indexBlock->_offsetOfNextAvailableSpace), sizeof(indexBlock-> _offsetOfNextAvailableSpace));
    }

//    osg::notify(osg::INFO)<<"indexBlock->_blockSize="<<indexBlock->_blockSize<<std::endl;
//    osg::notify(osg::INFO)<<"indexBlock->_filePositionNextIndexBlock="<<indexBlock->_filePositionNextIndexBlock<<std::endl;
//    osg::notify(osg::INFO)<<"indexBlock->_offsetOfNextAvailableSpace="<<indexBlock->_offsetOfNextAvailableSpace<<std::endl;

    indexBlock->allocateData(indexBlock->_blockSize);
    if (indexBlock->_data)
    {
        in.read(reinterpret_cast<char*>(indexBlock->_data),indexBlock->_blockSize);

        if (doEndianSwap)
        {
            char* ptr = indexBlock->_data;
            char* end_ptr = indexBlock->_data + indexBlock->_offsetOfNextAvailableSpace;
            while (ptr<end_ptr)
            {
                osg::swapBytes(ptr,sizeof(pos_type)); 
                ptr += sizeof(pos_type);

                osg::swapBytes(ptr,sizeof(size_type)); 
                ptr += sizeof(size_type);

                osg::swapBytes(ptr,sizeof(unsigned int)); 
                unsigned int filename_size; // = *(reinterpret_cast<unsigned int*>(ptr));
                _read(ptr, filename_size);
                ptr += sizeof(unsigned int);
                ptr += filename_size;

                osg::notify(osg::INFO)<<"filename size="<<filename_size<<std::endl;

            }
        }
    }
    else
    {
        osg::notify(osg::INFO)<<"Allocation Problem in OSGA_Archive::IndexBlock::read(std::istream& in)"<<std::endl;
        return 0;
    }

    osg::notify(osg::INFO)<<"Read index block"<<std::endl;
    
    return indexBlock.release();
    
}

std::string OSGA_Archive::IndexBlock::getFirstFileName() const
{
    char* ptr = _data;
    char* end_ptr = _data + _offsetOfNextAvailableSpace;
    if (ptr<end_ptr)
    {
        ptr += sizeof(pos_type);
        ptr += sizeof(size_type);

        unsigned int filename_size; // = *(reinterpret_cast<unsigned int*>(ptr));
        _read(ptr, filename_size);
        ptr += sizeof(unsigned int);

        return std::string(ptr, ptr+filename_size);
    }
    else
    {
        return std::string();
    }
}

bool OSGA_Archive::IndexBlock::getFileReferences(FileNamePositionMap& indexMap) const
{
    if (!_data || _offsetOfNextAvailableSpace==0) return false;
    
    bool valuesAdded = false;
    
    char* ptr = _data;
    char* end_ptr = _data + _offsetOfNextAvailableSpace;
    while (ptr<end_ptr)
    {
        pos_type position; // = *(reinterpret_cast<pos_type*>(ptr)); 
        _read(ptr, position);
        ptr += sizeof(pos_type);
        
        size_type size; // = *(reinterpret_cast<size_type*>(ptr)); 
        _read(ptr, size);
        ptr += sizeof(size_type);

        unsigned int filename_size; // = *(reinterpret_cast<unsigned int*>(ptr));
        _read(ptr, filename_size);
        ptr += sizeof(unsigned int);
        
        std::string filename(ptr, ptr+filename_size);
        
        // record this entry into the FileNamePositionMap. 
        // Requests for files will be in unix style even on Win32 so need unix style keys in map.
        indexMap[osgDB::convertFileNameToUnixStyle(filename)] = PositionSizePair(position,size);
        
        ptr += filename_size;
        
        valuesAdded = true;
    }
    return valuesAdded;
}

void OSGA_Archive::IndexBlock::write(std::ostream& out)
{
    pos_type currentPos = ARCHIVE_POS( out.tellp() );

    if (_filePosition==pos_type(0))
    {
        osg::notify(osg::INFO)<<"OSGA_Archive::IndexBlock::write() setting _filePosition"<<std::endl;
        _filePosition = currentPos;
    }
    else
    {
         out.seekp( STREAM_POS( _filePosition ) );
    }
    osg::notify(osg::INFO)<<"OSGA_Archive::IndexBlock::write() to _filePosition"<< ARCHIVE_POS( out.tellp() )<<std::endl;

    out.write(reinterpret_cast<char*>(&_blockSize), sizeof(_blockSize));
    out.write(reinterpret_cast<char*>(&_filePositionNextIndexBlock), sizeof(_filePositionNextIndexBlock));
    out.write(reinterpret_cast<char*>(&_offsetOfNextAvailableSpace), sizeof(_offsetOfNextAvailableSpace));

    out.write(reinterpret_cast<char*>(_data),_blockSize);

    if( _filePosition < currentPos ) // move file ptr to the end of file 
        out.seekp( STREAM_POS( currentPos ) );
    
    osg::notify(osg::INFO)<<"OSGA_Archive::IndexBlock::write() end"<<std::endl;
}


bool OSGA_Archive::IndexBlock::addFileReference(pos_type position, size_type size, const std::string& filename)
{
    if (spaceAvailable(position, size, filename))
    {
        char* ptr = _data+_offsetOfNextAvailableSpace;
        
        //*(reinterpret_cast<pos_type*>(ptr)) = position; 
        _write(ptr, position);
        ptr += sizeof(pos_type);
        
        //*(reinterpret_cast<size_type*>(ptr)) = size; 
        _write(ptr, size);
        ptr += sizeof(size_type);
        
        //*(reinterpret_cast<unsigned int*>(ptr)) = filename.size();
        _write(ptr, static_cast<unsigned int>(filename.size()));
        ptr += sizeof(unsigned int);
        
        for(unsigned int i=0;i<filename.size();++i, ++ptr)
        {
            *ptr = filename[i];
        }
        
        _offsetOfNextAvailableSpace = ptr-_data;
        
        _requiresWrite = true;

        osg::notify(osg::INFO)<<"OSGA_Archive::IndexBlock::addFileReference("<<(unsigned int)position<<", "<<filename<<")"<<std::endl;
        
        return true;
    }
    else
    {
        return false;
    }
}

void OSGA_Archive::IndexBlock::setPositionNextIndexBlock(pos_type position)
{
    _filePositionNextIndexBlock = position;
    _requiresWrite = true;
}

OSGA_Archive::OSGA_Archive()
{
}

OSGA_Archive::~OSGA_Archive()
{
    close();
}


bool OSGA_Archive::open(const std::string& filename, ArchiveStatus status, unsigned int indexBlockSize)
{
    SERIALIZER();

    if (status==READ)
    {
        _status = status;
        _input.open(filename.c_str(), std::ios_base::binary | std::ios_base::in);

        return _open(_input);
    }
    else
    {
        if (status==WRITE && open(filename,READ))
        {
            pos_type file_size( 0 );
            _input.seekg( 0, std::ios_base::end );
            file_size = ARCHIVE_POS( _input.tellg() ); 
            if( _input.is_open() && file_size <= 0 )
            {   // compute end of file postition manually ... 
                // seekp( 0, ios::end ), tellp( ) fails in 32 bit windows with files > 4 GiB
                size_t BlockHeaderSize = 
                    sizeof( unsigned int /*_blockSize*/ ) + 
                    sizeof( pos_type /*_filePositionNextIndexBlock*/ ) +
                    sizeof( unsigned int /*_offsetOfNextAvailableSpace*/ );
          
                for(IndexBlockList::iterator itr=_indexBlockList.begin();
                    itr!=_indexBlockList.end();
                    ++itr)
                {
                    pos_type end = (*itr)->getPosition() + BlockHeaderSize + (*itr)->getBlockSize();
                    if( file_size < end ) file_size = end;
                }

                for(FileNamePositionMap::iterator mitr=_indexMap.begin();
                    mitr!=_indexMap.end();
                    ++mitr)
                {
                    pos_type end = mitr->second.first + mitr->second.second;
                    if( file_size < end ) file_size = end;
                }
            }
            _input.close();
            _status = WRITE;

            _output.open(filename.c_str(), std::ios_base::binary | std::ios_base::in | std::ios_base::out);

            osg::notify(osg::INFO)<<"File position after open = "<<ARCHIVE_POS( _output.tellp() )<<" is_open "<<_output.is_open()<<std::endl;

            // place write position at end of file. 
            _output.seekp( STREAM_POS( file_size ) );

            osg::notify(osg::INFO)<<"File position after seekp = "<<ARCHIVE_POS( _output.tellp() )<<std::endl;

            osg::notify(osg::INFO)<<"OSGA_Archive::open("<<filename<<") open for writing"<<std::endl;

            return true;
        }
        else // no file opened or using create so resort to creating the archive.
        {
            osg::notify(osg::INFO)<<"OSGA_Archive::open("<<filename<<"), archive being created."<<std::endl;

            _status = WRITE;
            _output.open(filename.c_str(), std::ios_base::out | std::ios_base::binary | std::ios_base::trunc);
            _output<<"osga";
            _output.write(reinterpret_cast<const char*>(&ENDIAN_TEST_NUMBER),4);
            _output.write(reinterpret_cast<char*>(&s_currentSupportedVersion),sizeof(float));

            IndexBlock *indexBlock = new IndexBlock(indexBlockSize);
            if (indexBlock)
            {
                indexBlock->write(_output);
                _indexBlockList.push_back(indexBlock);
            }

            osg::notify(osg::INFO)<<"File position after write = "<<ARCHIVE_POS( _output.tellp() )<<std::endl;

            return true;
        }