mitab_maptoolblock.cpp

mitab,读取MapInfo的地图文件

/**********************************************************************
 * $Id: mitab_maptoolblock.cpp,v 1.7 2006/11/28 18:49:08 dmorissette Exp $
 *
 * Name:     mitab_maptoollock.cpp
 * Project:  MapInfo TAB Read/Write library
 * Language: C++
 * Purpose:  Implementation of the TABMAPToolBlock class used to handle
 *           reading/writing of the .MAP files' drawing tool blocks
 * Author:   Daniel Morissette, [e-mail]
 *
 **********************************************************************
 * Copyright (c) 1999, 2000, Daniel Morissette
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
 * DEALINGS IN THE SOFTWARE.
 **********************************************************************
 *
 * $Log: mitab_maptoolblock.cpp,v $
 * Revision 1.7  2006/11/28 18:49:08  dmorissette
 * Completed changes to split TABMAPObjectBlocks properly and produce an
 * optimal spatial index (bug 1585)
 *
 * Revision 1.6  2004/06/30 20:29:04  dmorissette
 * Fixed refs to old address [e-mail]
 *
 * Revision 1.5  2000/11/15 04:13:50  daniel
 * Fixed writing of TABMAPToolBlock to allocate a new block when full
 *
 * Revision 1.4  2000/02/28 17:03:30  daniel
 * Changed TABMAPBlockManager to TABBinBlockManager
 *
 * Revision 1.3  2000/01/15 22:30:44  daniel
 * Switch to MIT/X-Consortium OpenSource license
 *
 * Revision 1.2  1999/09/26 14:59:37  daniel
 * Implemented write support
 *
 * Revision 1.1  1999/09/16 02:39:17  daniel
 * Completed read support for most feature types
 *
 **********************************************************************/

#include "mitab.h"

/*=====================================================================
 *                      class TABMAPToolBlock
 *====================================================================*/

#define MAP_TOOL_HEADER_SIZE   8

/**********************************************************************
 *                   TABMAPToolBlock::TABMAPToolBlock()
 *
 * Constructor.
 **********************************************************************/
TABMAPToolBlock::TABMAPToolBlock(TABAccess eAccessMode /*= TABRead*/):
    TABRawBinBlock(eAccessMode, TRUE)
{
    m_nNextToolBlock = m_numDataBytes = 0;

    m_numBlocksInChain = 1;  // Current block counts as 1
 
    m_poBlockManagerRef = NULL;
}

/**********************************************************************
 *                   TABMAPToolBlock::~TABMAPToolBlock()
 *
 * Destructor.
 **********************************************************************/
TABMAPToolBlock::~TABMAPToolBlock()
{
   
}


/**********************************************************************
 *                   TABMAPToolBlock::EndOfChain()
 *
 * Return TRUE if we reached the end of the last block in the chain
 * TABMAPToolBlocks, or FALSE if there is still data to be read from 
 * this chain.
 **********************************************************************/
GBool TABMAPToolBlock::EndOfChain()
{
   if (m_pabyBuf && 
       (m_nCurPos < (m_numDataBytes+MAP_TOOL_HEADER_SIZE) || 
        m_nNextToolBlock > 0 ) )
   {
       return FALSE;  // There is still data to be read.
   }

   return TRUE;
}

/**********************************************************************
 *                   TABMAPToolBlock::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 
 * CPLError() will have been called.
 **********************************************************************/
int     TABMAPToolBlock::InitBlockFromData(GByte *pabyBuf,
                                           int nBlockSize, int nSizeUsed, 
                                           GBool bMakeCopy /* = TRUE */,
                                           FILE *fpSrc /* = NULL */, 
                                           int nOffset /* = 0 */)
{
    int nStatus;

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

    /*-----------------------------------------------------------------
     * Validate block type
     *----------------------------------------------------------------*/
    if (m_nBlockType != TABMAP_TOOL_BLOCK)
    {
        CPLError(CE_Failure, CPLE_FileIO,
                 "InitBlockFromData(): Invalid Block Type: got %d expected %d",
                 m_nBlockType, TABMAP_TOOL_BLOCK);
        CPLFree(m_pabyBuf);
        m_pabyBuf = NULL;
        return -1;
    }

    /*-----------------------------------------------------------------
     * Init member variables
     *----------------------------------------------------------------*/
    GotoByteInBlock(0x002);
    m_numDataBytes = ReadInt16();       /* Excluding 8 bytes header */

    m_nNextToolBlock = ReadInt32();

    /*-----------------------------------------------------------------
     * The read ptr is now located at the beginning of the data part.
     *----------------------------------------------------------------*/
    GotoByteInBlock(MAP_TOOL_HEADER_SIZE);

    return 0;
}

/**********************************************************************
 *                   TABMAPToolBlock::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 
 * CPLError() will have been called.
 **********************************************************************/
int     TABMAPToolBlock::CommitToFile()
{
    int nStatus = 0;

    if ( m_pabyBuf == NULL )
    {
        CPLError(CE_Failure, CPLE_AssertionFailed, 
                 "CommitToFile(): Block has not been initialized yet!");
        return -1;
    }

    /*-----------------------------------------------------------------
     * Make sure 8 bytes block header is up to date.
     *----------------------------------------------------------------*/
    GotoByteInBlock(0x000);

    WriteInt16(TABMAP_TOOL_BLOCK);    // Block type code
    WriteInt16(m_nSizeUsed - MAP_TOOL_HEADER_SIZE); // num. bytes used
    WriteInt32(m_nNextToolBlock);

    nStatus = CPLGetLastErrorNo();

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

    return nStatus;
}

/**********************************************************************
 *                   TABMAPToolBlock::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 
 * CPLError() will have been called.