avc_e00read.c

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

         * For some reason the file could not be opened... abort now.
         * An error message should have already been produced by 
         * AVCBinReadOpen()
         *------------------------------------------------------------*/
        if (psInfo->hFile == NULL)
            return NULL;

        pszLine = AVCE00GenStartSection(psInfo->hGenInfo, 
                                        psSect->eType, psSect->pszName);

        /*-------------------------------------------------------------
         * Reset the AVCE00GenInfo struct. so that it returns NULL,
         * which will force reading of the first object from the 
         * file on the next call to AVCE00ReadNextLine()
         *------------------------------------------------------------*/
        AVCE00GenReset(psInfo->hGenInfo);
        psInfo->iCurStep = AVC_GEN_DATA;
    }
    else if (psInfo->iCurStep == AVC_GEN_DATA &&
             (psSect->eType == AVCFileARC ||
              psSect->eType == AVCFilePAL ||
              psSect->eType == AVCFileRPL ||
              psSect->eType == AVCFileCNT ||
              psSect->eType == AVCFileLAB ||
              psSect->eType == AVCFileTOL ||
              psSect->eType == AVCFileTXT ||
              psSect->eType == AVCFileTX6 ||
              psSect->eType == AVCFileRXP    ) )
    {
    /*-----------------------------------------------------------------
     * Return the next line of an ARC/PAL/CNT/TOL/TXT object... 
     * if necessary, read the next object from the binary file.
     *----------------------------------------------------------------*/
        pszLine = AVCE00GenObject(psInfo->hGenInfo, 
                                  psSect->eType,
                  (psSect->eType==AVCFileARC?(void*)(psInfo->hFile->cur.psArc):
                   psSect->eType==AVCFilePAL?(void*)(psInfo->hFile->cur.psPal):
                   psSect->eType==AVCFileRPL?(void*)(psInfo->hFile->cur.psPal):
                   psSect->eType==AVCFileCNT?(void*)(psInfo->hFile->cur.psCnt):
                   psSect->eType==AVCFileLAB?(void*)(psInfo->hFile->cur.psLab):
                   psSect->eType==AVCFileTOL?(void*)(psInfo->hFile->cur.psTol):
                   psSect->eType==AVCFileTXT?(void*)(psInfo->hFile->cur.psTxt):
                   psSect->eType==AVCFileTX6?(void*)(psInfo->hFile->cur.psTxt):
                   psSect->eType==AVCFileRXP?(void*)(psInfo->hFile->cur.psRxp):
                   NULL),
                                  TRUE);
        if (pszLine == NULL)
        {
            /*---------------------------------------------------------
             * Current object is finished generating... we need to read 
             * a new one from the file.
             *--------------------------------------------------------*/
            if (AVCBinReadNextObject(psInfo->hFile) != NULL)
            {
                pszLine = AVCE00GenObject(psInfo->hGenInfo, 
                                          psSect->eType,
                  (psSect->eType==AVCFileARC?(void*)(psInfo->hFile->cur.psArc):
                   psSect->eType==AVCFilePAL?(void*)(psInfo->hFile->cur.psPal):
                   psSect->eType==AVCFileRPL?(void*)(psInfo->hFile->cur.psPal):
                   psSect->eType==AVCFileCNT?(void*)(psInfo->hFile->cur.psCnt):
                   psSect->eType==AVCFileLAB?(void*)(psInfo->hFile->cur.psLab):
                   psSect->eType==AVCFileTOL?(void*)(psInfo->hFile->cur.psTol):
                   psSect->eType==AVCFileTXT?(void*)(psInfo->hFile->cur.psTxt):
                   psSect->eType==AVCFileTX6?(void*)(psInfo->hFile->cur.psTxt):
                   psSect->eType==AVCFileRXP?(void*)(psInfo->hFile->cur.psRxp):
                   NULL),
                                          FALSE);
            }            
        }
        if (pszLine == NULL)
        {
            /*---------------------------------------------------------
             * Still NULL ??? This means we finished reading this file...
             * Start returning the "end of section" line(s)...
             *--------------------------------------------------------*/
            AVCBinReadClose(psInfo->hFile);
            psInfo->hFile = NULL;
            psInfo->iCurStep = AVC_GEN_ENDSECTION;
            pszLine = AVCE00GenEndSection(psInfo->hGenInfo, psSect->eType,
                                          FALSE);
        }
    }
    /*=================================================================
     *                          PRJ
     *================================================================*/
    else if (psInfo->iCurStep == AVC_GEN_NOTSTARTED &&
              psSect->eType == AVCFilePRJ   )
    {
        /*-------------------------------------------------------------
         * Start processing of PRJ section... return first header line.
         *------------------------------------------------------------*/
        pszLine = AVCE00GenStartSection(psInfo->hGenInfo, 
                                        psSect->eType, NULL);

        psInfo->hFile = NULL;
        psInfo->iCurStep = AVC_GEN_DATA;
    }
    else if (psInfo->iCurStep == AVC_GEN_DATA &&
             psSect->eType == AVCFilePRJ  )
    {
        /*-------------------------------------------------------------
         * Return the next line of a PRJ section
         *------------------------------------------------------------*/
        if (psInfo->hFile == NULL)
        {
            /*---------------------------------------------------------
             * File has not been read yet...
             * Read the PRJ file, and return the first PRJ line.
             *--------------------------------------------------------*/
            psInfo->hFile = AVCBinReadOpen(psInfo->pszCoverPath, 
                                           psSect->pszFilename, 
                                           psInfo->eCoverType, psSect->eType,
                                           psInfo->psDBCSInfo);

            /* For some reason the file could not be opened... abort now.
             * An error message should have already been produced by 
             * AVCBinReadOpen()
             */
            if (psInfo->hFile == NULL)
                return NULL;

            pszLine = AVCE00GenPrj(psInfo->hGenInfo, 
                                   psInfo->hFile->cur.papszPrj, FALSE);
        }
        else
        {
            /*---------------------------------------------------------
             * Generate the next line of output.
             *--------------------------------------------------------*/
            pszLine = AVCE00GenPrj(psInfo->hGenInfo, 
                                   psInfo->hFile->cur.papszPrj, TRUE);
        }

        if (pszLine == NULL)
        {
            /*---------------------------------------------------------
             * Still NULL ??? This means we finished generating this PRJ 
             * section...
             * Start returning the "end of section" line(s)...
             *--------------------------------------------------------*/
            AVCBinReadClose(psInfo->hFile);
            psInfo->hFile = NULL;
            psInfo->iCurStep = AVC_GEN_ENDSECTION;
            pszLine = AVCE00GenEndSection(psInfo->hGenInfo, psSect->eType,
                                          FALSE);
        }
    }
    else if (psInfo->iCurStep != AVC_GEN_ENDSECTION)
    {
        /* We should never get here! */
        CPLAssert(FALSE);
    }


    /*=================================================================
     *                End of section, for all files
     *================================================================*/

    /*-----------------------------------------------------------------
     * Finished processing of an ARC, PAL, CNT, LAB, TOL, PRJ file ...
     * continue returning the "end of section" line(s), and move the pointer
     * to the next section once we're done.
     *----------------------------------------------------------------*/
    if (psInfo->iCurStep == AVC_GEN_ENDSECTION && pszLine == NULL)
    {
        pszLine = AVCE00GenEndSection(psInfo->hGenInfo, psSect->eType, TRUE);

        if (pszLine == NULL)
        {
            /*---------------------------------------------------------
             * Finished returning the last lines of the section...
             * proceed to the next section...
             * OK, I don't really like recursivity either... but it was
             * the simplest way to do this, and anyways we should never
             * have more than one level of recursivity.
             *--------------------------------------------------------*/
            if (psInfo->bReadAllSections)
                psInfo->iCurSection++;
            else
                psInfo->iCurSection = psInfo->numSections;
            psInfo->iCurStep = AVC_GEN_NOTSTARTED;

            pszLine = AVCE00ReadNextLine(psInfo);
        }
    }

    return pszLine;
}



/**********************************************************************
 *                         AVCE00ReadSectionsList()
 *
 * Returns an array of AVCE00Section structures that describe the
 * squeleton of the whole coverage.  The value of *numSect will be
 * set to the number of sections in the array.
 *
 * You can scan the returned array, and use AVCE00ReadGotoSection() to move
 * the read pointer directly to the beginning of a given section
 * of the file.
 *
 * Sections of type AVCFileUnknown correspond to lines in the
 * E00 output that are not directly linked to any coverage file, like 
 * the "EXP 0" line, the "IFO X", "SIN X", etc.
 *
 * THE RETURNED ARRAY IS AN INTERNAL STRUCTURE AND SHOULD NOT BE
 * MODIFIED OR FREED BY THE CALLER... its contents will be valid
 * for as long as the coverage will remain open.
 **********************************************************************/
AVCE00Section *AVCE00ReadSectionsList(AVCE00ReadPtr psInfo, int *numSect)
{
    CPLErrorReset();

    *numSect = psInfo->numSections;
    return psInfo->pasSections;
}

/**********************************************************************
 *                         AVCE00ReadGotoSection()
 *
 * Move the read pointer to the E00 section (coverage file) described in 
 * the psSect structure.  Call AVCE00ReadListSections() to get the list of
 * sections for the current coverage.
 *
 * if bContinue=TRUE, then reading will automatically continue with the
 * next sections of the file once the requested section is finished.
 * Otherwise, if bContinue=FALSE then reading will stop at the end
 * of this section (i.e. AVCE00ReadNextLine() will return NULL when 
 * it reaches the end of this section)
 *
 * Sections of type AVCFileUnknown returned by AVCE00ReadListSections()
 * correspond to lines in the E00 output that are not directly linked
 * to any coverage file, like the "EXP 0" line, the "IFO X", "SIN X", etc.
 * You can jump to these sections or any other one without problems.
 *
 * This function returns 0 on success or -1 on error.
 **********************************************************************/
int AVCE00ReadGotoSection(AVCE00ReadPtr psInfo, AVCE00Section *psSect,
                          GBool bContinue)
{
    int     iSect;
    GBool   bFound = FALSE;

    CPLErrorReset();

    /*-----------------------------------------------------------------
     * Locate the requested section in the array.
     *----------------------------------------------------------------*/
    for(iSect=0; iSect<psInfo->numSections; iSect++)
    {
        if (psInfo->pasSections[iSect].eType == psSect->eType &&
            EQUAL(psInfo->pasSections[iSect].pszName, psSect->pszName))
        {
            bFound = TRUE;
            break;
        }
    }

    /*-----------------------------------------------------------------
     * Not found ... generate an error...
     *----------------------------------------------------------------*/
    if (!bFound)
    {
        CPLError(CE_Failure, CPLE_IllegalArg, 
                 "Requested E00 section does not exist!");
        return -1;
    }

    /*-----------------------------------------------------------------
     * Found it ... close current section and get ready to read 
     * the new one.
     *----------------------------------------------------------------*/
    if (psInfo->hFile)
    {
        AVCBinReadClose(psInfo->hFile);
        psInfo->hFile = NULL;
    }

    psInfo->bReadAllSections = bContinue;
    psInfo->iCurSection = iSect;
    psInfo->iCurStep = AVC_GEN_NOTSTARTED;

    return 0;
}

/**********************************************************************
 *                         AVCE00ReadRewind()
 *
 * Rewinds the AVCE00ReadPtr just like the stdio rewind() 
 * function would do if you were reading an ASCII E00 file.
 *
 * Returns 0 on success or -1 on error.
 **********************************************************************/
int  AVCE00ReadRewind(AVCE00ReadPtr psInfo)
{
    CPLErrorReset();

    return AVCE00ReadGotoSection(psInfo, &(psInfo->pasSections[0]), TRUE);
}