tabmapindexblock.cpp

linux下一款GIS程序源码

// tabmapindexblock.cpp: implementation of the TABMAPIndexBlock class.
//
//////////////////////////////////////////////////////////////////////

#include "tabmapindexblock.h"

#include "ugk_errhandle.h"
#include "ugk_memopr.h"

/**********************************************************************
 *                   TABMAPIndexBlock::TABMAPIndexBlock()
 *
 * Constructor.
 **********************************************************************/
TABMAPIndexBlock::TABMAPIndexBlock(TABAccess eAccessMode /*= TABRead*/):
    TABRawBinBlock(eAccessMode, TRUE)
{
    m_numEntries = 0;

    m_nMinX = 1000000000;
    m_nMinY = 1000000000;
    m_nMaxX = -1000000000;
    m_nMaxY = -1000000000;

    m_poCurChild = NULL;
    m_nCurChildIndex = -1;
    m_poParentRef = NULL;
    m_poBlockManagerRef = NULL;
}


/**********************************************************************
 *                   TABMAPIndexBlock::~TABMAPIndexBlock()
 *
 * Destructor.
 **********************************************************************/
TABMAPIndexBlock::~TABMAPIndexBlock()
{
    if (m_poCurChild)
    {
        if (m_eAccess == TABWrite || m_eAccess == TABReadWrite)
            m_poCurChild->CommitToFile();
        delete m_poCurChild;
    }
}



/**********************************************************************
 *                   TABMAPIndexBlock::InitBlockFromData()
 *
 * Perform some initialization on the block after its binary data has
 * been set or changed (or loaded from a file).
 *
 * Returns 0 if succesful or -1 if an error happened, in which case 
 * UGKError() will have been called.
 **********************************************************************/
int     TABMAPIndexBlock::InitBlockFromData(UGKByte *pabyBuf, int nSize, 
                                            UGKBool bMakeCopy /* = TRUE */,
                                            FILE *fpSrc /* = NULL */, 
                                            int nOffset /* = 0 */)
{
    int nStatus;

    /*-----------------------------------------------------------------
     * First of all, we must call the base class' InitBlockFromData()
     *----------------------------------------------------------------*/
    nStatus = TABRawBinBlock::InitBlockFromData(pabyBuf, nSize, bMakeCopy,
                                            fpSrc, nOffset);
    if (nStatus != 0)   
        return nStatus;

    /*-----------------------------------------------------------------
     * Validate block type
     *----------------------------------------------------------------*/
    if (m_nBlockType != TABMAP_INDEX_BLOCK)
    {
        UGKError(ET_Failure, UGKErr_FileIO,
                  "InitBlockFromData(): Invalid Block Type: got %d expected %d",
                  m_nBlockType, TABMAP_INDEX_BLOCK);
        UGK_Free(m_pabyBuf);
        m_pabyBuf = NULL;
        return -1;
    }

    /*-----------------------------------------------------------------
     * Init member variables
     *----------------------------------------------------------------*/
    GotoByteInBlock(0x002);
    m_numEntries = ReadInt16();

    if (m_numEntries > 0)
        ReadAllEntries(); //读取所有的TABMAPIndexEntry

    return 0;
}


/**********************************************************************
 *                   TABMAPIndexBlock::CommitToFile()
 *
 * Commit the current state of the binary block to the file to which 
 * it has been previously attached.
 *
 * This method makes sure all values are properly set in the map object
 * block header and then calls TABRawBinBlock::CommitToFile() to do
 * the actual writing to disk.
 *
 * Returns 0 if succesful or -1 if an error happened, in which case 
 * UGKError() will have been called.
 **********************************************************************/
int     TABMAPIndexBlock::CommitToFile()
{
    int nStatus = 0;

    if ( m_pabyBuf == NULL )
    {
        UGKError(ET_Failure, UGKErr_AssertionFailed, 
                  "CommitToFile(): Block has not been initialized yet!");
        return -1;
    }

    /*-----------------------------------------------------------------
     * Commit child first
     *----------------------------------------------------------------*/
    if (m_poCurChild)
    {
        if (m_poCurChild->CommitToFile() != 0)
            return -1;
    }

    /*-----------------------------------------------------------------
     * Make sure 4 bytes block header is up to date.
     *----------------------------------------------------------------*/
    GotoByteInBlock(0x000);

    WriteInt16(TABMAP_INDEX_BLOCK);    // Block type code
    WriteInt16(m_numEntries);

    nStatus = UGKGetLastErrorNo();

    /*-----------------------------------------------------------------
     * Loop through all entries, writing each of them, and calling
     * CommitToFile() (recursively) on any child index entries we may
     * encounter.
     *----------------------------------------------------------------*/
    for(int i=0; nStatus == 0 && i<m_numEntries; i++)
    {
        if (nStatus == 0)
            nStatus = WriteNextEntry(&(m_asEntries[i]));
    }


    /*-----------------------------------------------------------------
     * OK, call the base class to write the block to disk.
     *----------------------------------------------------------------*/
    if (nStatus == 0)
        nStatus = TABRawBinBlock::CommitToFile();

    return nStatus;
}



/**********************************************************************
 *                   TABMAPIndexBlock::InitNewBlock()
 *
 * Initialize a newly created block so that it knows to which file it
 * is attached, its block size, etc . and then perform any specific 
 * initialization for this block type, including writing a default 
 * block header, etc. and leave the block ready to receive data.
 *
 * This is an alternative to calling ReadFromFile() or InitBlockFromData()
 * that puts the block in a stable state without loading any initial
 * data in it.
 *
 * Returns 0 if succesful or -1 if an error happened, in which case 
 * UGKError() will have been called.
 **********************************************************************/
int     TABMAPIndexBlock::InitNewBlock(FILE *fpSrc, int nBlockSize, 
                                        int nFileOffset /* = 0*/)
{
    /*-----------------------------------------------------------------
     * Start with the default initialisation
     *----------------------------------------------------------------*/
    if ( TABRawBinBlock::InitNewBlock(fpSrc, nBlockSize, nFileOffset) != 0)
        return -1;

    /*-----------------------------------------------------------------
     * And then set default values for the block header.
     *----------------------------------------------------------------*/
    m_numEntries = 0;

    m_nMinX = 1000000000;
    m_nMinY = 1000000000;
    m_nMaxX = -1000000000;
    m_nMaxY = -1000000000;

    if (m_eAccess != TABRead)
    {
        GotoByteInBlock(0x000);

        WriteInt16(TABMAP_INDEX_BLOCK);     // Block type code
        WriteInt16(0);                      // num. index entries
    }

    if (UGKGetLastErrorNo() != 0)
        return -1;

    return 0;
}





/**********************************************************************
 *                   TABMAPIndexBlock::ReadNextEntry()
 *
 * Read the next index entry from the block and fill the sEntry
 * structure. 
 *
 * Returns 0 if succesful or -1 if we reached the end of the block.
 **********************************************************************/
int     TABMAPIndexBlock::ReadNextEntry(TABMAPIndexEntry *psEntry)
{
    if (m_nCurPos < 4)
        GotoByteInBlock( 0x004 );

    if (m_nCurPos > 4+(20*m_numEntries) )
    {
        // End of BLock
        return -1;
    }

    psEntry->XMin = ReadInt32();
    psEntry->YMin = ReadInt32();
    psEntry->XMax = ReadInt32();
    psEntry->YMax = ReadInt32();
    psEntry->nBlockPtr = ReadInt32();

    if (UGKGetLastErrorNo() != 0)
        return -1;

    return 0;
}


/**********************************************************************
 *                   TABMAPIndexBlock::ReadAllEntries()
 *
 * Init the block by reading all entries from the data block.
 *
 * Returns 0 if succesful or -1 on error.
 **********************************************************************/
int     TABMAPIndexBlock::ReadAllEntries()
{
    assert(m_numEntries <= TAB_MAX_ENTRIES_INDEX_BLOCK);
    if (m_numEntries == 0)
        return 0;
    
    if (GotoByteInBlock( 0x004 ) != 0)
        return -1;

    for(int i=0; i<m_numEntries; i++)
    {
        if ( ReadNextEntry(&(m_asEntries[i])) != 0)
            return -1;
    }

    return 0;
}


/**********************************************************************
 *                   TABMAPIndexBlock::WriteNextEntry()
 *
 * Write the sEntry index entry at current position in the block.
 *
 * Returns 0 if succesful or -1 if we reached the end of the block.
 **********************************************************************/
int     TABMAPIndexBlock::WriteNextEntry(TABMAPIndexEntry *psEntry)
{
    if (m_nCurPos < 4)
        GotoByteInBlock( 0x004 );

    WriteInt32(psEntry->XMin);
    WriteInt32(psEntry->YMin);
    WriteInt32(psEntry->XMax);
    WriteInt32(psEntry->YMax);
    WriteInt32(psEntry->nBlockPtr);

    if (UGKGetLastErrorNo() != 0)
        return -1;

    return 0;
}

/**********************************************************************
 *                   TABMAPIndexBlock::GetNumFreeEntries()
 *
 * Return the number of available entries in this block.
 *
 * __TODO__ This function could eventually be improved to search
 *          children leaves as well.
 **********************************************************************/
int     TABMAPIndexBlock::GetNumFreeEntries()
{
    /* nMaxEntries = (m_nBlockSize-4)/20;*/

    return (TAB_MAX_ENTRIES_INDEX_BLOCK - m_numEntries);
}


/**********************************************************************
 *                   TABMAPIndexBlock::GetEntry()
 *
 * Fetch a reference to the requested entry.
 *
 * @param iIndex index of entry, must be from 0 to GetNumEntries()-1. 
 *
 * @return a reference to the internal copy of the entry, or NULL if out
 * of range. 
 **********************************************************************/
TABMAPIndexEntry *TABMAPIndexBlock::GetEntry( int iIndex )
{
    if( iIndex < 0 || iIndex >= m_numEntries )
        return NULL;

    return m_asEntries + iIndex;
}


/**********************************************************************
 *                   TABMAPIndexBlock::GetCurMaxDepth()
 *
 * Return maximum depth in the currently loaded part of the index tree
 **********************************************************************/
int     TABMAPIndexBlock::GetCurMaxDepth()
{
    if (m_poCurChild)