tabindfile.cpp

linux下一款GIS程序源码

// tabindfile.cpp: implementation of the TABINDFile class.
//
//////////////////////////////////////////////////////////////////////

#include "tabindfile.h"

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

#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,
                     UGKBool bTestOpenNoError /*=FALSE*/)
{
    int         nLen;

    if (m_fp)
    {
        UGKError(ET_Failure, UGKErr_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
    {
        UGKError(ET_Failure, UGKErr_FileIO,
                 "Open() failed: access mode \"%s\" not supported", pszAccess);
        return -1;
    }

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

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

#ifndef WIN32APP
    TABAdjustFilenameExtension(m_pszFname);
#endif

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

    if (m_fp == NULL)
    {
        if (!bTestOpenNoError)
            UGKError(ET_Failure, UGKErr_FileIO,
                     "Open() failed for %s", m_pszFname);

        UGK_Free(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])
            UGK_Free(m_papbyKeyBuffers[iIndex]);
    }
    UGK_Free(m_papoIndexRootNodes);
    m_papoIndexRootNodes = NULL;
    UGK_Free(m_papbyKeyBuffers);
    m_papbyKeyBuffers = NULL;
    m_numIndexes = 0;

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

    UGK_Free(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()
{

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

    /*-----------------------------------------------------------------
     * In ReadWrite mode, we need to init BlockManager with file size
     *----------------------------------------------------------------*/
    struct stat  sStatBuf;
    if (m_eAccessMode == TABReadWrite && stat(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);
    UGKUInt32 nMagicCookie = poHeaderBlock->ReadInt32();
    if (nMagicCookie != IND_MAGIC_COOKIE)
    {
        UGKError(ET_Failure, UGKErr_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)
    {
        UGKError(ET_Failure, UGKErr_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**)UGK_Calloc(m_numIndexes,
                                                   sizeof(TABINDNode*));

    m_papbyKeyBuffers = (UGKByte **)UGK_Calloc(m_numIndexes, sizeof(UGKByte*));

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

    for(int iIndex=0; iIndex<m_numIndexes; iIndex++)
    {
        /*-------------------------------------------------------------
         * Read next index definition
         *------------------------------------------------------------*/
        UGKInt32 nRootNodePtr = poHeaderBlock->ReadInt32();
        poHeaderBlock->ReadInt16();   // skip... max. num of entries per node
        int nTreeDepth = poHeaderBlock->ReadByte();
        int nKeyLength = poHeaderBlock->ReadByte();
        poHeaderBlock->GotoByteRel(8); // skip next 8 bytes;

        /*-------------------------------------------------------------
         * And init root node for this index.
         * Note that if nRootNodePtr==0 then this means that the 
         * corresponding index does not exist (i.e. has been deleted?)
         * so we simply do not allocate the root node in this case.
         * An error will be produced if the user tries to access this index
         * later during execution.
         *------------------------------------------------------------*/
        if (nRootNodePtr > 0)
        {
            m_papoIndexRootNodes[iIndex] = new TABINDNode(m_eAccessMode);
            if (m_papoIndexRootNodes[iIndex]->InitNode(m_fp, nRootNodePtr,
                                                       nKeyLength, nTreeDepth,
                                                       FALSE,
                                                       &m_oBlockManager)!= 0)
            {
                // CPLError has already been called
                delete poHeaderBlock;
                return -1;
            }

            // Alloc a temporary key buffer for this index.
            // This buffer will be used by the BuildKey() method
            m_papbyKeyBuffers[iIndex] = (UGKByte *)UGK_Calloc(nKeyLength+1, 
                                                           sizeof(UGKByte));
        }
        else
        {
            m_papoIndexRootNodes[iIndex] = NULL;
            m_papbyKeyBuffers[iIndex] = NULL;
        }
    }

    /*-----------------------------------------------------------------
     * OK, we won't need the header block any more... free it.
     *----------------------------------------------------------------*/
    delete poHeaderBlock;

    return 0;
}



/**********************************************************************
 *                   TABINDFile::WriteHeader()
 *
 * (private method)
 * Write the header block based on current index information.
 *
 * Returns 0 on success, -1 on error.
 **********************************************************************/
int TABINDFile::WriteHeader()
{
    assert(m_fp);
    assert(m_eAccessMode == TABWrite || m_eAccessMode == TABReadWrite);

    /*-----------------------------------------------------------------
     * Write the 48 bytes of file header
     *----------------------------------------------------------------*/
    TABRawBinBlock *poHeaderBlock;
    poHeaderBlock = new TABRawBinBlock(m_eAccessMode, TRUE);
    poHeaderBlock->InitNewBlock(m_fp, 512, 0);

    poHeaderBlock->WriteInt32( IND_MAGIC_COOKIE );

    poHeaderBlock->WriteInt16( 100 );   // ???
    poHeaderBlock->WriteInt16( 512 );   // ???
    poHeaderBlock->WriteInt32( 0 );     // ???

    poHeaderBlock->WriteInt16( m_numIndexes );

    poHeaderBlock->WriteInt16( 0x15e7); // ???

    poHeaderBlock->WriteInt16( 10 );    // ???
    poHeaderBlock->WriteInt16( 0x611d); // ???

    poHeaderBlock->WriteZeros( 28 );

    /*-----------------------------------------------------------------
     * The first index definition starts at byte 48
     *----------------------------------------------------------------*/
    for(int iIndex=0; iIndex<m_numIndexes; iIndex++)
    {
        TABINDNode *poRootNode = m_papoIndexRootNodes[iIndex];

        if (poRootNode)
        {
            /*---------------------------------------------------------
             * Write next index definition
             *--------------------------------------------------------*/
            poHeaderBlock->WriteInt32(poRootNode->GetNodeBlockPtr());
            poHeaderBlock->WriteInt16(poRootNode->GetMaxNumEntries());
            poHeaderBlock->WriteByte( poRootNode->GetSubTreeDepth());
            poHeaderBlock->WriteByte( poRootNode->GetKeyLength());

            poHeaderBlock->WriteZeros( 8 );
        }
        else