avc_bin.c

GIS系统支持库Geospatial Data Abstraction Library代码.GDAL is a translator library for raster geospatial dat

    {
        psTxt->anJust1[i] = 0;
        psTxt->anJust2[i] = 0;
    }

    return 0;
}

/**********************************************************************
 *                          AVCBinReadNextTxt()
 *
 * Read the next TXT/TX6/TX7 structure from the file.
 *
 * Returns a pointer to a static AVCTxt structure whose contents will be
 * valid only until the next call or NULL if an error happened or if EOF
 * was reached.  
 **********************************************************************/
AVCTxt *AVCBinReadNextTxt(AVCBinFile *psFile)
{
    int nStatus = 0;

    if ((psFile->eFileType != AVCFileTXT && psFile->eFileType != AVCFileTX6) ||
        AVCRawBinEOF(psFile->psRawBinFile) )
    {
        return NULL;
    }

    /* AVCCoverPC have a different TXT format than AVCCoverV7
     *
     * Note: Some Weird coverages use the PC TXT structure, and some use the
     *       V7 structure.  We distinguish them using the header's precision
     *       field in AVCBinReadRewind().
     */
    if (psFile->eFileType == AVCFileTXT &&
        (psFile->eCoverType == AVCCoverPC ||
         psFile->eCoverType == AVCCoverWeird) )
    {    
        /* TXT file in PC Coverages (and some Weird Coverages)
         */
        nStatus = _AVCBinReadNextPCCoverageTxt(psFile->psRawBinFile, 
                                               psFile->cur.psTxt,
                                               psFile->nPrecision);
    }
    else
    {   
        /* TXT in V7 Coverages (and some Weird Coverages), and TX6/TX7 in 
         * all coverage types
         */
        nStatus = _AVCBinReadNextTxt(psFile->psRawBinFile, psFile->cur.psTxt,
                                     psFile->nPrecision);
    }

    if (nStatus != 0)
    {
        return NULL;
    }

    return psFile->cur.psTxt;
}


/*=====================================================================
 *                              RXP
 *====================================================================*/

/**********************************************************************
 *                          _AVCBinReadNextRxp()
 *
 * (This function is for internal library use... external calls should
 * go to AVCBinReadNextRxp() instead)
 *
 * Read the next RXP (Region something...) structure from the file.
 *
 * Returns 0 on success or -1 on error.
 **********************************************************************/
int _AVCBinReadNextRxp(AVCRawBinFile *psFile, AVCRxp *psRxp, 
                       int nPrecision)
{

    psRxp->n1  = AVCRawBinReadInt32(psFile);
    if (AVCRawBinEOF(psFile))
        return -1;
    psRxp->n2  = AVCRawBinReadInt32(psFile);

    return 0;
}

/**********************************************************************
 *                          AVCBinReadNextRxp()
 *
 * Read the next RXP structure from the file.
 *
 * Returns a pointer to a static AVCRxp structure whose contents will be
 * valid only until the next call or NULL if an error happened or if EOF
 * was reached.  
 **********************************************************************/
AVCRxp *AVCBinReadNextRxp(AVCBinFile *psFile)
{
    if (psFile->eFileType != AVCFileRXP ||
        AVCRawBinEOF(psFile->psRawBinFile) ||
        _AVCBinReadNextRxp(psFile->psRawBinFile, psFile->cur.psRxp,
                           psFile->nPrecision) !=0)
    {
        return NULL;
    }

    return psFile->cur.psRxp;
}

/*=====================================================================
 *                         NATIVE (V7.x) TABLEs
 *
 * Note: Also applies to AVCCoverWeird
 *====================================================================*/

/**********************************************************************
 *                          _AVCBinReadNextArcDir()
 *
 * (This function is for internal library use... external calls should
 * go to AVCBinReadOpen() with type AVCFileTABLE instead)
 *
 * Read the next record from an arc.dir (or "arcdr9") file.
 *
 * Note that arc.dir files have no header... they start with the
 * first record immediately.
 *
 * Returns 0 on success or -1 on error.
 **********************************************************************/
int _AVCBinReadNextArcDir(AVCRawBinFile *psFile, AVCTableDef *psArcDir)
{
    int i;

    /* Arc/Info Table name 
     */
    AVCRawBinReadString(psFile, 32, psArcDir->szTableName);
    psArcDir->szTableName[32] = '\0';

    if (AVCRawBinEOF(psFile))
        return -1;

    /* "ARC####" basename for .DAT and .NIT files
     */
    AVCRawBinReadString(psFile, 8, psArcDir->szInfoFile);
    psArcDir->szInfoFile[7] = '\0';
    for (i=6; i>0 && psArcDir->szInfoFile[i]==' '; i--)
        psArcDir->szInfoFile[i] = '\0';

    psArcDir->numFields = AVCRawBinReadInt16(psFile);
    psArcDir->nRecSize  = AVCRawBinReadInt16(psFile);

    AVCRawBinFSeek(psFile, 18, SEEK_CUR);     /* Skip 18 bytes */
    
    psArcDir->bDeletedFlag = AVCRawBinReadInt16(psFile);
    psArcDir->numRecords = AVCRawBinReadInt32(psFile);

    AVCRawBinFSeek(psFile, 10, SEEK_CUR);     /* Skip 10 bytes */
    
    AVCRawBinReadBytes(psFile, 2, psArcDir->szExternal);
    psArcDir->szExternal[2] = '\0';

    AVCRawBinFSeek(psFile, 300, SEEK_CUR);  /* Skip the remaining 300 bytes */

    return 0;
}

/**********************************************************************
 *                          _AVCBinReadNextNit()
 *
 * (This function is for internal library use... external calls should
 * go to AVCBinReadOpen() with type AVCFileTABLE instead)
 *
 * Read the next record from an arc####.nit file.
 *
 * Note that arc####.nit files have no header... they start with the
 * first record immediately.
 *
 * Returns 0 on success or -1 on error.
 **********************************************************************/
int _AVCBinReadNextArcNit(AVCRawBinFile *psFile, AVCFieldInfo *psField)
{
    AVCRawBinReadString(psFile, 16, psField->szName);
    psField->szName[16] = '\0';

    if (AVCRawBinEOF(psFile))
        return -1;

    psField->nSize     = AVCRawBinReadInt16(psFile);
    psField->v2        = AVCRawBinReadInt16(psFile);  /* Always -1 ? */
    psField->nOffset   = AVCRawBinReadInt16(psFile);
    psField->v4        = AVCRawBinReadInt16(psFile);  /* Always 4 ?  */
    psField->v5        = AVCRawBinReadInt16(psFile);  /* Always -1 ? */
    psField->nFmtWidth = AVCRawBinReadInt16(psFile);
    psField->nFmtPrec  = AVCRawBinReadInt16(psFile);
    psField->nType1    = AVCRawBinReadInt16(psFile);
    psField->nType2    = AVCRawBinReadInt16(psFile);  /* Always 0 ? */
    psField->v10       = AVCRawBinReadInt16(psFile);  /* Always -1 ? */
    psField->v11       = AVCRawBinReadInt16(psFile);  /* Always -1 ? */
    psField->v12       = AVCRawBinReadInt16(psFile);  /* Always -1 ? */
    psField->v13       = AVCRawBinReadInt16(psFile);  /* Always -1 ? */

    AVCRawBinReadString(psFile, 16, psField->szAltName);   /* Always Blank ? */
    psField->szAltName[16] = '\0';

    AVCRawBinFSeek(psFile, 56, SEEK_CUR);             /* Skip 56 bytes */
    
    psField->nIndex    = AVCRawBinReadInt16(psFile);

    AVCRawBinFSeek(psFile, 28, SEEK_CUR);  /* Skip the remaining 28 bytes */

    return 0;
}

/**********************************************************************
 *                          _AVCBinReadGetInfoFilename()
 *
 * Look for the DAT or NIT files for a given table... returns TRUE if
 * they exist, or FALSE otherwise.
 *
 * If pszRetFnmae/pszRetNitFile != NULL then the filename with full path 
 * will be copied to the specified buffer.
 **********************************************************************/
GBool _AVCBinReadGetInfoFilename(const char *pszInfoPath, 
                                 const char *pszBasename,
                                 const char *pszDatOrNit,
                                 AVCCoverType eCoverType,
                                 char *pszRetFname)
{
    GBool       bFilesExist = FALSE;
    char        *pszBuf = NULL;
    VSIStatBuf  sStatBuf;

    if (pszRetFname)
        pszBuf = pszRetFname;
    else
        pszBuf = (char*)CPLMalloc((strlen(pszInfoPath)+strlen(pszBasename)+10)*
                                  sizeof(char));

    if (eCoverType == AVCCoverWeird)
    {
        sprintf(pszBuf, "%s%s%s", pszInfoPath, pszBasename, pszDatOrNit);
    }
    else
    {
        sprintf(pszBuf, "%s%s.%s", pszInfoPath, pszBasename, pszDatOrNit);
    }

    AVCAdjustCaseSensitiveFilename(pszBuf);

    if (VSIStat(pszBuf, &sStatBuf) == 0)
        bFilesExist = TRUE;

    if (eCoverType == AVCCoverWeird && !bFilesExist)
    {
        /* In some cases, the filename can be truncated to 8 chars
         * and we end up with "ARC000DA"... check that possibility.
         */
        pszBuf[strlen(pszBuf)-1] = '\0';

        AVCAdjustCaseSensitiveFilename(pszBuf);

        if (VSIStat(pszBuf, &sStatBuf) == 0)
            bFilesExist = TRUE;
    }

    if (pszRetFname == NULL)
        CPLFree(pszBuf);

    return bFilesExist;

}

/**********************************************************************
 *                          _AVCBinReadInfoFilesExist()
 *
 * Look for the DAT and NIT files for a given table... returns TRUE if
 * they exist, or FALSE otherwise.
 *
 * If pszRetDatFile/pszRetNitFile != NULL then the .DAT and .NIT filename
 * without the info path will be copied to the specified buffers.
 **********************************************************************/
GBool _AVCBinReadInfoFileExists(const char *pszInfoPath, 
                                const char *pszBasename,
                                AVCCoverType eCoverType)
{

    return (_AVCBinReadGetInfoFilename(pszInfoPath, pszBasename, 
                                       "dat", eCoverType, NULL) == TRUE &&
            _AVCBinReadGetInfoFilename(pszInfoPath, pszBasename, 
                                       "nit", eCoverType, NULL) == TRUE);

}

/**********************************************************************
 *                          AVCBinReadListTables()
 *
 * Scan the arc.dir file and return stringlist with one entry for the
 * Arc/Info name of each table that belongs to the specified coverage.
 * Pass pszCoverName = NULL to get the list of all tables.
 *
 * ppapszArcDatFiles if not NULL will be set to point to a stringlist
 * with the corresponding "ARC????" info file basenames corresponding
 * to each table found.
 *
 * Note that arc.dir files have no header... they start with the
 * first record immediately.
 *
 * In AVCCoverWeird, the file is called "arcdr9"
 *
 * Returns a stringlist that should be deallocated by the caller
 * with CSLDestroy(), or NULL on error.
 **********************************************************************/
char **AVCBinReadListTables(const char *pszInfoPath, const char *pszCoverName,
                            char ***ppapszArcDatFiles, AVCCoverType eCoverType,
                            AVCDBCSInfo *psDBCSInfo)
{
    char              **papszList = NULL;
    char               *pszFname;
    char                szNameToFind[33] = "";
    int                 nLen;
    AVCRawBinFile      *hFile;
    AVCTableDef         sEntry;

    if (ppapszArcDatFiles)
        *ppapszArcDatFiles = NULL;

    /*----------------------------------------------------------------- 
     * All tables that belong to a given coverage have their name starting
     * with the coverage name (in uppercase letters), followed by a 3 
     * letters extension.
     *----------------------------------------------------------------*/
    if (pszCoverName != NULL)
        sprintf(szNameToFind, "%-.28s.", pszCoverName);
    nLen = strlen(szNameToFind);

    /*----------------------------------------------------------------- 
     * Open the arc.dir and add all entries that match the criteria
     * to our list.
     * In AVCCoverWeird, the file is called "arcdr9"
     *----------------------------------------------------------------*/
    pszFname = (char*)CPLMalloc((strlen(pszInfoPath)+9)*sizeof(char));
    if (eCoverType == AVCCoverWeird)
        sprintf(pszFname, "%sarcdr9", pszInfoPath);
    else
        sprintf(pszFname, "%sarc.dir", pszInfoPath);

    AVCAdjustCaseSensitiveFilename(pszFname);

    hFile = AVCRawBinOpen(pszFname, "r", AVC_COVER_BYTE_ORDER(eCoverType),
                          psDBCSInfo);

    if (hFile)
    {
        while (!AVCRawBinEOF(hFile) &&
               _AVCBinReadNextArcDir(hFile, &sEntry) == 0)
        {
            if (/* sEntry.numRecords > 0 && (DO NOT skip empty tables) */
                !sEntry.bDeletedFlag &&
                (pszCoverName == NULL ||
                 EQUALN(szNameToFind, sEntry.szTableName, nLen)) &&
                _AVCBinReadInfoFileExists(pszInfoPath, 
                                          sEntry.szInfoFile, 
                                          eCoverType) )
            {
                papszList = CSLAddString(papszList, sEntry.szTableName);

                if (ppapszArcDatFile