shpopen.c

用于读取TAB、MIF、SHP文件的类

    {
	psSHP->adBoundsMin[0] = MIN(psSHP->adBoundsMin[0],psObject->padfX[i]);
	psSHP->adBoundsMin[1] = MIN(psSHP->adBoundsMin[1],psObject->padfY[i]);
	psSHP->adBoundsMin[2] = MIN(psSHP->adBoundsMin[2],psObject->padfZ[i]);
	psSHP->adBoundsMin[3] = MIN(psSHP->adBoundsMin[3],psObject->padfM[i]);
	psSHP->adBoundsMax[0] = MAX(psSHP->adBoundsMax[0],psObject->padfX[i]);
	psSHP->adBoundsMax[1] = MAX(psSHP->adBoundsMax[1],psObject->padfY[i]);
	psSHP->adBoundsMax[2] = MAX(psSHP->adBoundsMax[2],psObject->padfZ[i]);
	psSHP->adBoundsMax[3] = MAX(psSHP->adBoundsMax[3],psObject->padfM[i]);
    }

    return( nShapeId  );
}

/************************************************************************/
/*                          SHPReadObject()                             */
/*                                                                      */
/*      Read the vertices, parts, and other non-attribute information	*/
/*	for one shape.							*/
/************************************************************************/

SHPObject SHPAPI_CALL1(*)
SHPReadObject( SHPHandle psSHP, int hEntity )

{
    SHPObject		*psShape;

/* -------------------------------------------------------------------- */
/*      Validate the record/entity number.                              */
/* -------------------------------------------------------------------- */
    if( hEntity < 0 || hEntity >= psSHP->nRecords )
        return( NULL );

/* -------------------------------------------------------------------- */
/*      Ensure our record buffer is large enough.                       */
/* -------------------------------------------------------------------- */
    if( psSHP->panRecSize[hEntity]+8 > psSHP->nBufSize )
    {
	psSHP->nBufSize = psSHP->panRecSize[hEntity]+8;
	psSHP->pabyRec = (uchar *) SfRealloc(psSHP->pabyRec,psSHP->nBufSize);
    }

/* -------------------------------------------------------------------- */
/*      Read the record.                                                */
/* -------------------------------------------------------------------- */
    if( fseek( psSHP->fpSHP, psSHP->panRecOffset[hEntity], 0 ) != 0 
        || fread( psSHP->pabyRec, psSHP->panRecSize[hEntity]+8, 1, 
                  psSHP->fpSHP ) != 1 )
    {
        /*
         * TODO - mloskot: Consider detailed diagnostics of shape file,
         * for example to detect if file is truncated.
         */

#ifdef USE_CPL
        CPLDebug( "Shape", "Error in fseek() or fread() reading object from .shp file." );
#endif
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*	Allocate and minimally initialize the object.			*/
/* -------------------------------------------------------------------- */
    psShape = (SHPObject *) calloc(1,sizeof(SHPObject));
    psShape->nShapeId = hEntity;
    psShape->bMeasureIsUsed = FALSE;

    memcpy( &psShape->nSHPType, psSHP->pabyRec + 8, 4 );
    if( bBigEndian ) SwapWord( 4, &(psShape->nSHPType) );

/* ==================================================================== */
/*  Extract vertices for a Polygon or Arc.				*/
/* ==================================================================== */
    if( psShape->nSHPType == SHPT_POLYGON || psShape->nSHPType == SHPT_ARC
        || psShape->nSHPType == SHPT_POLYGONZ
        || psShape->nSHPType == SHPT_POLYGONM
        || psShape->nSHPType == SHPT_ARCZ
        || psShape->nSHPType == SHPT_ARCM
        || psShape->nSHPType == SHPT_MULTIPATCH )
    {
	int32		nPoints, nParts;
	int    		i, nOffset;

/* -------------------------------------------------------------------- */
/*	Get the X/Y bounds.						*/
/* -------------------------------------------------------------------- */
        memcpy( &(psShape->dfXMin), psSHP->pabyRec + 8 +  4, 8 );
        memcpy( &(psShape->dfYMin), psSHP->pabyRec + 8 + 12, 8 );
        memcpy( &(psShape->dfXMax), psSHP->pabyRec + 8 + 20, 8 );
        memcpy( &(psShape->dfYMax), psSHP->pabyRec + 8 + 28, 8 );

	if( bBigEndian ) SwapWord( 8, &(psShape->dfXMin) );
	if( bBigEndian ) SwapWord( 8, &(psShape->dfYMin) );
	if( bBigEndian ) SwapWord( 8, &(psShape->dfXMax) );
	if( bBigEndian ) SwapWord( 8, &(psShape->dfYMax) );

/* -------------------------------------------------------------------- */
/*      Extract part/point count, and build vertex and part arrays      */
/*      to proper size.                                                 */
/* -------------------------------------------------------------------- */
	memcpy( &nPoints, psSHP->pabyRec + 40 + 8, 4 );
	memcpy( &nParts, psSHP->pabyRec + 36 + 8, 4 );

	if( bBigEndian ) SwapWord( 4, &nPoints );
	if( bBigEndian ) SwapWord( 4, &nParts );

	psShape->nVertices = nPoints;
        psShape->padfX = (double *) calloc(nPoints,sizeof(double));
        psShape->padfY = (double *) calloc(nPoints,sizeof(double));
        psShape->padfZ = (double *) calloc(nPoints,sizeof(double));
        psShape->padfM = (double *) calloc(nPoints,sizeof(double));

	psShape->nParts = nParts;
        psShape->panPartStart = (int *) calloc(nParts,sizeof(int));
        psShape->panPartType = (int *) calloc(nParts,sizeof(int));

        for( i = 0; i < nParts; i++ )
            psShape->panPartType[i] = SHPP_RING;

/* -------------------------------------------------------------------- */
/*      Copy out the part array from the record.                        */
/* -------------------------------------------------------------------- */
	memcpy( psShape->panPartStart, psSHP->pabyRec + 44 + 8, 4 * nParts );
	for( i = 0; i < nParts; i++ )
	{
	    if( bBigEndian ) SwapWord( 4, psShape->panPartStart+i );
	}

	nOffset = 44 + 8 + 4*nParts;

/* -------------------------------------------------------------------- */
/*      If this is a multipatch, we will also have parts types.         */
/* -------------------------------------------------------------------- */
        if( psShape->nSHPType == SHPT_MULTIPATCH )
        {
            memcpy( psShape->panPartType, psSHP->pabyRec + nOffset, 4*nParts );
            for( i = 0; i < nParts; i++ )
            {
                if( bBigEndian ) SwapWord( 4, psShape->panPartType+i );
            }

            nOffset += 4*nParts;
        }
        
/* -------------------------------------------------------------------- */
/*      Copy out the vertices from the record.                          */
/* -------------------------------------------------------------------- */
	for( i = 0; i < nPoints; i++ )
	{
	    memcpy(psShape->padfX + i,
		   psSHP->pabyRec + nOffset + i * 16,
		   8 );

	    memcpy(psShape->padfY + i,
		   psSHP->pabyRec + nOffset + i * 16 + 8,
		   8 );

	    if( bBigEndian ) SwapWord( 8, psShape->padfX + i );
	    if( bBigEndian ) SwapWord( 8, psShape->padfY + i );
	}

        nOffset += 16*nPoints;
        
/* -------------------------------------------------------------------- */
/*      If we have a Z coordinate, collect that now.                    */
/* -------------------------------------------------------------------- */
        if( psShape->nSHPType == SHPT_POLYGONZ
            || psShape->nSHPType == SHPT_ARCZ
            || psShape->nSHPType == SHPT_MULTIPATCH )
        {
            memcpy( &(psShape->dfZMin), psSHP->pabyRec + nOffset, 8 );
            memcpy( &(psShape->dfZMax), psSHP->pabyRec + nOffset + 8, 8 );
            
            if( bBigEndian ) SwapWord( 8, &(psShape->dfZMin) );
            if( bBigEndian ) SwapWord( 8, &(psShape->dfZMax) );
            
            for( i = 0; i < nPoints; i++ )
            {
                memcpy( psShape->padfZ + i,
                        psSHP->pabyRec + nOffset + 16 + i*8, 8 );
                if( bBigEndian ) SwapWord( 8, psShape->padfZ + i );
            }

            nOffset += 16 + 8*nPoints;
        }

/* -------------------------------------------------------------------- */
/*      If we have a M measure value, then read it now.  We assume      */
/*      that the measure can be present for any shape if the size is    */
/*      big enough, but really it will only occur for the Z shapes      */
/*      (options), and the M shapes.                                    */
/* -------------------------------------------------------------------- */
        if( psSHP->panRecSize[hEntity]+8 >= nOffset + 16 + 8*nPoints )
        {
            memcpy( &(psShape->dfMMin), psSHP->pabyRec + nOffset, 8 );
            memcpy( &(psShape->dfMMax), psSHP->pabyRec + nOffset + 8, 8 );
            
            if( bBigEndian ) SwapWord( 8, &(psShape->dfMMin) );
            if( bBigEndian ) SwapWord( 8, &(psShape->dfMMax) );
            
            for( i = 0; i < nPoints; i++ )
            {
                memcpy( psShape->padfM + i,
                        psSHP->pabyRec + nOffset + 16 + i*8, 8 );
                if( bBigEndian ) SwapWord( 8, psShape->padfM + i );
            }
            psShape->bMeasureIsUsed = TRUE;
        }
    }

/* ==================================================================== */
/*  Extract vertices for a MultiPoint.					*/
/* ==================================================================== */
    else if( psShape->nSHPType == SHPT_MULTIPOINT
             || psShape->nSHPType == SHPT_MULTIPOINTM
             || psShape->nSHPType == SHPT_MULTIPOINTZ )
    {
	int32		nPoints;
	int    		i, nOffset;

	memcpy( &nPoints, psSHP->pabyRec + 44, 4 );
	if( bBigEndian ) SwapWord( 4, &nPoints );

	psShape->nVertices = nPoints;
        psShape->padfX = (double *) calloc(nPoints,sizeof(double));
        psShape->padfY = (double *) calloc(nPoints,sizeof(double));
        psShape->padfZ = (double *) calloc(nPoints,sizeof(double));
        psShape->padfM = (double *) calloc(nPoints,sizeof(double));

	for( i = 0; i < nPoints; i++ )
	{
	    memcpy(psShape->padfX+i, psSHP->pabyRec + 48 + 16 * i, 8 );
	    memcpy(psShape->padfY+i, psSHP->pabyRec + 48 + 16 * i + 8, 8 );

	    if( bBigEndian ) SwapWord( 8, psShape->padfX + i );
	    if( bBigEndian ) SwapWord( 8, psShape->padfY + i );
	}

        nOffset = 48 + 16*nPoints;
        
/* -------------------------------------------------------------------- */
/*	Get the X/Y bounds.						*/
/* -------------------------------------------------------------------- */
        memcpy( &(psShape->dfXMin), psSHP->pabyRec + 8 +  4, 8 );
        memcpy( &(psShape->dfYMin), psSHP->pabyRec + 8 + 12, 8 );
        memcpy( &(psShape->dfXMax), psSHP->pabyRec + 8 + 20, 8 );
        memcpy( &(psShape->dfYMax), psSHP->pabyRec + 8 + 28, 8 );

	if( bBigEndian ) SwapWord( 8, &(psShape->dfXMin) );
	if( bBigEndian ) SwapWord( 8, &(psShape->dfYMin) );
	if( bBigEndian ) SwapWord( 8, &(psShape->dfXMax) );
	if( bBigEndian ) SwapWord( 8, &(psShape->dfYMax) );

/* -------------------------------------------------------------------- */
/*      If we have a Z coordinate, collect that now.                    */
/* -------------------------------------------------------------------- */
        if( psShape->nSHPType == SHPT_MULTIPOINTZ )
        {
            memcpy( &(psShape->dfZMin), psSHP->pabyRec + nOffset, 8 );
            memcpy( &(psShape->dfZMax), psSHP->pabyRec + nOffset + 8, 8 );
            
            if( bBigEndian ) SwapWord( 8, &(psShape->dfZMin) );
            if( bBigEndian ) SwapWord( 8, &(psShape->dfZMax) );
            
            for( i = 0; i < nPoints; i++ )
            {
                memcpy( psShape->padfZ + i,
                        psSHP->pabyRec + nOffset + 16 + i*8, 8 );
                if( bBigEndian ) SwapWord( 8, psShape->padfZ + i );
            }

            nOffset += 16 + 8*nPoints;
        }

/* -------------------------------------------------------------------- */
/*      If we have a M measure value, then read it now.  We assume      */
/*      that the measure can be present for any shape if the size is    */
/*      big enough, but really it will only occur for the Z shapes      */
/*      (options), and the M shapes.                                    */
/* -------------------------------------------------------------------- */
        if( psSHP->panRecSize[hEntity]+8 >= nOffset + 16 + 8*nPoints )
        {
            memcpy( &(psShape->dfMMin), psSHP->pabyRec + nOffset, 8 );
            memcpy( &(psShape->dfMMax), psSHP->pabyRec + nOffset + 8, 8 );
            
            if( bBigEndian ) SwapWord( 8, &(psShape->dfMMin) );
            if( bBigEndian ) SwapWord( 8, &(psShape->dfMMax) );
            
            for( i = 0; i < nPoints; i++ )
            {
                memcpy( psShape->padfM + i,
                        psSHP->pabyRec + nOffset + 16 + i*8, 8 );
                if( bBigEndian ) SwapWord( 8, psShape->padfM + i );
            }
            psShape->bMeasureIsUsed = TRUE;
        }
    }

/* ==================================================================== */
/*      Extract vertices for a point.                                   */
/* ==================================================================== */
    else if( psShape->nSHPType == SHPT_POINT
             || psShape->nSHPType == SHPT_POINTM
             || psShape->nSHPType == SHPT_POINTZ )
    {
        int	nOffset;
        
	psShape->nVertices = 1;
        psShape->padfX = (double *) calloc(1,sizeof(double));
        psShape->padfY = (double *) calloc(1,sizeof(double));
        psShape->padfZ = (double *) calloc(1,sizeof(double));
        psShape->padfM = (double *) calloc(1,sizeof(double));

	memcpy( psShape->padfX, psSHP->pabyRec + 12, 8 );
	memcpy( psShape->padfY, psSHP->pabyRec + 20, 8 );

	if( bBigEndian ) SwapWord( 8, psShape->padfX );
	if( bBigEndian ) SwapWord( 8, psShape->padfY );

        nOffset = 20 + 8;
        
/* -------------------------------------------------------------------- */
/*      If we have a Z coordinate, collect that now.                    */
/* -------------------------------------------------------------------- */
        if( psShape->nSHPType == SHPT_POINTZ )
        {
            memcpy( psShape->padfZ, psSHP->pabyRec + nOffset, 8 );
        
            if( bBigEndian ) SwapWord( 8, psShape->padfZ );
            
            nOffset += 8;
        }

/* -------------------------------------------------------------------- */
/*      If we have a M measure value, then read it now.  We assume      */
/*      that the measure can be present for any shape if the size is    */
/*      big enough, but really it will only occur for the Z shapes      */
/*      (options), and the M shapes.                                    */
/* -------------------------------------------------------------------- */
        if( psSHP->panRecSize[hEntity]+8 >= nOffset + 8 )
        {
            memcpy( psShape->padfM, psSHP->pabyRec + nOffset, 8 );
        
            if( bBigEndian ) SwapWord( 8, psShape->padfM );
            psShape->bMeasureIsUsed = TRUE;
        }

/* -------------------------------------------------------------------- */
/*      Since no extents are supplied in the record, we will apply      */
/*      them from the single vertex.                                    */
/* -------------------------------------------------------------------- */
        psShape->dfXMin = psShape->dfXMax = psShape->padfX[0];
        psShape->dfYMin = psShape->dfYMax = psSh