mitab_indfile.cpp

在linux环境下

/**********************************************************************
 * $Id: mitab_indfile.cpp,v 1.10 2004/06/30 20:29:04 dmorissette Exp $
 *
 * Name:     mitab_indfile.cpp
 * Project:  MapInfo TAB Read/Write library
 * Language: C++
 * Purpose:  Implementation of the TABINDFile class used to handle
 *           access to .IND file (table field indexes) attached to a .DAT file
 * Author:   Daniel Morissette, [e-mail]
 *
 **********************************************************************
 * Copyright (c) 1999-2001, 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_indfile.cpp,v $
 * Revision 1.10  2004/06/30 20:29:04  dmorissette
 * Fixed refs to old address [e-mail]
 *
 * Revision 1.9  2003/07/24 02:45:57  daniel
 * Fixed problem scanning node in TABINDNode::FindNext() - bug 2176, FW
 *
 * Revision 1.8  2001/05/01 03:38:23  daniel
 * Added update support (allows creating new index in existing IND files).
 *
 * Revision 1.7  2000/11/13 22:17:57  daniel
 * When a (child) node's first entry is replaced by InsertEntry() then make
 * sure that node's key is updated in its parent node.
 *
 * Revision 1.6  2000/03/01 00:32:00  daniel
 * Added support for float keys, and completed support for generating indexes
 *
 * Revision 1.5  2000/02/28 16:57:42  daniel
 * Added support for writing indexes
 *
 * Revision 1.4  2000/01/15 22:30:44  daniel
 * Switch to MIT/X-Consortium OpenSource license
 *
 * Revision 1.3  1999/12/14 05:52:05  daniel
 * Fixed compile error on Windows
 *
 * Revision 1.2  1999/12/14 02:19:42  daniel
 * Completed .IND support for simple TABViews
 *
 * Revision 1.1  1999/11/20 15:49:07  daniel
 * Initial version
 *
 **********************************************************************/

#include "mitab.h"
#include "mitab_utils.h"

#include <ctype.h>      /* toupper() */

/*=====================================================================
 *                      class TABINDFile
 *====================================================================*/

#define IND_MAGIC_COOKIE  24242424

/**********************************************************************
 *                   TABINDFile::TABINDFile()
 *
 * Constructor.
 **********************************************************************/
TABINDFile::TABINDFile()
{
    m_fp = NULL;
    m_pszFname = NULL;
    m_eAccessMode = TABRead;
    m_numIndexes = 0;
    m_papoIndexRootNodes = NULL;
    m_papbyKeyBuffers = NULL;
}

/**********************************************************************
 *                   TABINDFile::~TABINDFile()
 *
 * Destructor.
 **********************************************************************/
TABINDFile::~TABINDFile()
{
    Close();
}

/**********************************************************************
 *                   TABINDFile::Open()
 *
 * Open a .IND file, read the header and the root nodes for all the
 * field indexes, and be ready to search the indexes.
 *
 * If the filename that is passed in contains a .DAT extension then
 * the extension will be changed to .IND before trying to open the file.
 *
 * Note that we pass a pszAccess flag, but only read access is supported
 * for now (and there are no plans to support write.)
 *
 * Set bTestOpenNoError=TRUE to silently return -1 with no error message
 * if the file cannot be opened because it does not exist.
 *
 * Returns 0 on success, -1 on error.
 **********************************************************************/
int TABINDFile::Open(const char *pszFname, const char *pszAccess,
                     GBool bTestOpenNoError /*=FALSE*/)
{
    int         nLen;

    if (m_fp)
    {
        CPLError(CE_Failure, CPLE_FileIO,
                 "Open() failed: object already contains an open file");
        return -1;
    }

    /*-----------------------------------------------------------------
     * Validate access mode and make sure we use binary access.
     * Note that for write access, we actually need read/write access to
     * the file.
     *----------------------------------------------------------------*/
    if (EQUALN(pszAccess, "r", 1) && strchr(pszAccess, '+') != NULL)
    {
        m_eAccessMode = TABReadWrite;
        pszAccess = "rb+";
    }
    else if (EQUALN(pszAccess, "r", 1))
    {
        m_eAccessMode = TABRead;
        pszAccess = "rb";
    }
    else if (EQUALN(pszAccess, "w", 1))
    {
        m_eAccessMode = TABWrite;
        pszAccess = "wb+";
    }
    else
    {
        CPLError(CE_Failure, CPLE_FileIO,
                 "Open() failed: access mode \"%s\" not supported", pszAccess);
        return -1;
    }

    /*-----------------------------------------------------------------
     * Change .DAT (or .TAB) extension to .IND if necessary
     *----------------------------------------------------------------*/
    m_pszFname = CPLStrdup(pszFname);

    nLen = strlen(m_pszFname);
    if (nLen > 4 && !EQUAL(m_pszFname+nLen-4, ".IND") )
        strcpy(m_pszFname+nLen-4, ".ind");

#ifndef _WIN32
    TABAdjustFilenameExtension(m_pszFname);
#endif

    /*-----------------------------------------------------------------
     * Open file
     *----------------------------------------------------------------*/
    m_fp = VSIFOpen(m_pszFname, pszAccess);

    if (m_fp == NULL)
    {
        if (!bTestOpenNoError)
            CPLError(CE_Failure, CPLE_FileIO,
                     "Open() failed for %s", m_pszFname);

        CPLFree(m_pszFname);
        m_pszFname = NULL;
        return -1;
    }

    /*-----------------------------------------------------------------
     * Reset block manager to allocate first block at byte 512, after header.
     *----------------------------------------------------------------*/
    m_oBlockManager.Reset();
    m_oBlockManager.AllocNewBlock();

    /*-----------------------------------------------------------------
     * Read access: Read the header block
     * This will also alloc and init the array of index root nodes.
     *----------------------------------------------------------------*/
    if ((m_eAccessMode == TABRead || m_eAccessMode == TABReadWrite) &&
        ReadHeader() != 0)
    {
        // Failed reading header... CPLError() has already been called
        Close();
        return -1;
    }

    /*-----------------------------------------------------------------
     * Write access: Init class members and write a dummy header block
     *----------------------------------------------------------------*/
    if (m_eAccessMode == TABWrite)
    {
        m_numIndexes = 0;

        if (WriteHeader() != 0)
        {
            // Failed writing header... CPLError() has already been called
            Close();
            return -1;
        }
    }

    return 0;
}

/**********************************************************************
 *                   TABINDFile::Close()
 *
 * Close current file, and release all memory used.
 *
 * Returns 0 on success, -1 on error.
 **********************************************************************/
int TABINDFile::Close()
{
    if (m_fp == NULL)
        return 0;

    /*-----------------------------------------------------------------
     * In Write Mode, commit all indexes to the file
     *----------------------------------------------------------------*/
    if (m_eAccessMode == TABWrite || m_eAccessMode == TABReadWrite)
    {
        WriteHeader();

        for(int iIndex=0; iIndex<m_numIndexes; iIndex++)
        {
            if (m_papoIndexRootNodes &&
                m_papoIndexRootNodes[iIndex])
            {
                m_papoIndexRootNodes[iIndex]->CommitToFile();
            }
        }
    }

    /*-----------------------------------------------------------------
     * Free index nodes in memory
     *----------------------------------------------------------------*/
    for (int iIndex=0; iIndex<m_numIndexes; iIndex++)
    {
        if (m_papoIndexRootNodes && m_papoIndexRootNodes[iIndex])
            delete m_papoIndexRootNodes[iIndex];
        if (m_papbyKeyBuffers && m_papbyKeyBuffers[iIndex])
            CPLFree(m_papbyKeyBuffers[iIndex]);
    }
    CPLFree(m_papoIndexRootNodes);
    m_papoIndexRootNodes = NULL;
    CPLFree(m_papbyKeyBuffers);
    m_papbyKeyBuffers = NULL;
    m_numIndexes = 0;

    /*-----------------------------------------------------------------
     * Close file
     *----------------------------------------------------------------*/
    VSIFClose(m_fp);
    m_fp = NULL;

    CPLFree(m_pszFname);
    m_pszFname = NULL;

    return 0;
}


/**********************************************************************
 *                   TABINDFile::ReadHeader()
 *
 * (private method)
 * Read the header block and init all class members for read access.
 *
 * Returns 0 on success, -1 on error.
 **********************************************************************/
int TABINDFile::ReadHeader()
{

    CPLAssert(m_fp);
    CPLAssert(m_eAccessMode == TABRead || m_eAccessMode == TABReadWrite);

    /*-----------------------------------------------------------------
     * In ReadWrite mode, we need to init BlockManager with file size
     *----------------------------------------------------------------*/
    VSIStatBuf  sStatBuf;
    if (m_eAccessMode == TABReadWrite && VSIStat(m_pszFname, &sStatBuf) != -1)
    {
        m_oBlockManager.SetLastPtr(((sStatBuf.st_size-1)/512)*512);
    }

    /*-----------------------------------------------------------------
     * Read the header block
     *----------------------------------------------------------------*/
    TABRawBinBlock *poHeaderBlock;
    poHeaderBlock = new TABRawBinBlock(m_eAccessMode, TRUE);
    if (poHeaderBlock->ReadFromFile(m_fp, 0, 512) != 0)
    {
        // CPLError() has already been called.
        delete poHeaderBlock;
        return -1;
    }

    poHeaderBlock->GotoByteInBlock(0);
    GUInt32 nMagicCookie = poHeaderBlock->ReadInt32();
    if (nMagicCookie != IND_MAGIC_COOKIE)
    {
        CPLError(CE_Failure, CPLE_FileIO,
                 "%s: Invalid Magic Cookie: got %d, expected %d",
                 m_pszFname, nMagicCookie, IND_MAGIC_COOKIE);
        delete poHeaderBlock;
        return -1;
    }

    poHeaderBlock->GotoByteInBlock(12);
    m_numIndexes = poHeaderBlock->ReadInt16();
    if (m_numIndexes < 1 || m_numIndexes > 29)
    {
        CPLError(CE_Failure, CPLE_FileIO,
                 "Invalid number of indexes (%d) in file %s",
                 m_numIndexes, m_pszFname);
        delete poHeaderBlock;
        return -1;
    }

    /*-----------------------------------------------------------------
     * Alloc and init the array of index root nodes.
     *----------------------------------------------------------------*/
    m_papoIndexRootNodes = (TABINDNode**)CPLCalloc(m_numIndexes,
                                                   sizeof(TABINDNode*));

    m_papbyKeyBuffers = (GByte **)CPLCalloc(m_numIndexes, sizeof(GByte*));

    /* First index def. starts at byte 48 */
    poHeaderBlock->GotoByteInBlock(48);

    for(int iIndex=0; iIndex<m_numIndexes; iIndex++)