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Write.h

Go to the documentation of this file.

#ifndef Impala_Core_Table_Write_h
#define Impala_Core_Table_Write_h

#include "Core/Table/TableTem.h"
#include "Core/Column/Write.h"
#include "Persistency/File.h"
#include <ctime>

namespace Impala
{
namespace Core
{
namespace Table
{


template<class TableT>
inline void
Write(TableT* table, Util::IOBuffer* buffer, bool binary)
{
    ILOG_VAR(Impala.Core.Table.Write);
    if (!table)
    {
        ILOG_ERROR("No table");
        return;
    }
    
    // count columns
    int columnCount = 0;
    if(table->GetColumn1()->Valid()) columnCount = 1;
    if(table->GetColumn2()->Valid()) columnCount = 2;
    if(table->GetColumn3()->Valid()) columnCount = 3;
    if(table->GetColumn4()->Valid()) columnCount = 4;
    if(table->GetColumn5()->Valid()) columnCount = 5;
    if(table->GetColumn6()->Valid()) columnCount = 6;
    if(table->GetColumn7()->Valid()) columnCount = 7;
    if(table->GetColumn8()->Valid()) columnCount = 8;
    if(table->GetColumn9()->Valid()) columnCount = 9;

    // construct table header
    const int TABLEHEADERSIZE = 1024;
    std::ostringstream oss;
    oss << "impalatableversion: 2, columns: " << columnCount << ", "
        << "size: " << table->Size() << "\n";
    for(int i = 1; i <= columnCount; i++)
        oss << "column" << i << ": " << table->GetColName(i) << "\n";
    
    oss << "info: " << table->GetInfo() << "\n";
    
    std::time_t rawtime;
    std::time ( &rawtime );
    oss << "computedon: " << std::ctime (&rawtime);  // ctime comes with \n
    oss << "computedby: Impala " << IMPALA_VERSION_STR
        << " (svnversion " << SVN_VERSION_STR << ") compiled "
        << __DATE__ << " " << __TIME__ << "\n";
    while(oss.tellp() < TABLEHEADERSIZE)
        oss << ' ';
    oss.seekp(TABLEHEADERSIZE - 1, std::ios::beg);
    oss << '\n';

    // write the table header
    buffer->Write(oss.str().c_str(), TABLEHEADERSIZE);

    // write footer placeholder
    Int64 footer[16];
    for(int i = 0; i < 16; i++)
        footer[i] = 0;
    Util::IOBuffer::PositionType footerStartPos = buffer->GetPosition();
    buffer->Write(footer, sizeof(Int64) * 16);
    
    // write all columns + collect footer information
    // "impalafooter" 0x01 0x00 0x00 0x00
    footer[0] = 0x6F66616C61706D69LL;
    footer[1] = 0x000000017265746FLL;
    footer[2] = columnCount;
    footer[3] = table->Size();
    footer[4] = buffer->GetPosition();
    Column::Write(table->GetColumn1(), table->Size(), buffer, binary);
    footer[5] = buffer->GetPosition();
    Column::Write(table->GetColumn2(), table->Size(), buffer, binary);
    footer[6] = buffer->GetPosition();
    Column::Write(table->GetColumn3(), table->Size(), buffer, binary);
    footer[7] = buffer->GetPosition();
    Column::Write(table->GetColumn4(), table->Size(), buffer, binary);
    footer[8] = buffer->GetPosition();
    Column::Write(table->GetColumn5(), table->Size(), buffer, binary);
    footer[9] = buffer->GetPosition();
    Column::Write(table->GetColumn6(), table->Size(), buffer, binary);
    footer[10] = buffer->GetPosition();
    Column::Write(table->GetColumn7(), table->Size(), buffer, binary);
    footer[11] = buffer->GetPosition();
    Column::Write(table->GetColumn8(), table->Size(), buffer, binary);
    footer[12] = buffer->GetPosition();
    Column::Write(table->GetColumn9(), table->Size(), buffer, binary);
    footer[13] = buffer->GetPosition();
    footer[14] = 0;
    footer[15] = 0;
    
    Util::IOBuffer::PositionType eofPos = buffer->GetPosition();
    // write footer
    buffer->Seek(footerStartPos, SEEK_SET);
    buffer->Write(footer, sizeof(Int64) * 16);
    buffer->Seek(eofPos, SEEK_SET); // get back to EOF
}

#ifndef REPOSITORY_USED // Here comes the deprecated stuff
template<class TableT>
inline bool
Write(TableT* table, String fileName, Util::Database* db, bool binary)
{
    Util::IOBuffer* buf = db->GetIOBuffer(fileName, false, false, "tmp", 0, true);
    if (buf)
    {
        Write(table, buf, binary);
        delete buf;
        return true;
    }
    return false;
}
#endif // REPOSITORY_USED

template<class TableT>
inline bool
Write(TableT* table, Persistency::File file)
{
    Util::IOBuffer* buf = file.GetWriteBuffer();
    if (buf)
    {
        Write(table, buf, true);
        delete buf;
        return true;
    }
    return false;
}

} // namespace Table
} // namespace Core
} // namespace Impala

#endif

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