getPoint3dm_p()

int getPoint3dm_p	(	const POINTARRAY *	pa,
		int	n,
		POINT3DM *	op
	)

Definition at line 266 of file lwgeom_api.c.

References POINTARRAY::flags, FLAGS_GET_ZM, FLAGS_NDIMS, getPoint_internal(), LWDEBUGF, lwerror(), lwnotice(), POINT3DM::m, NO_M_VALUE, and POINTARRAY::npoints.

Referenced by getPoint3dm(), LWGEOM_m_point(), lwline_is_trajectory(), and lwpoint_getPoint3dm_p().

{
        uint8_t *ptr;
        int zmflag;

        if ( ! pa )
        {
                lwerror("%s [%d] NULL POINTARRAY input", __FILE__, __LINE__);
                return 0;
        }

        if ( (n<0) || (n>=pa->npoints))
        {
                lwnotice("%s [%d] called with n=%d and npoints=%d", __FILE__, __LINE__, n, pa->npoints);
                return 0;
        }

        LWDEBUGF(2, "getPoint3dm_p(%d) called on array of %d-dimensions / %u pts",
                 n, FLAGS_NDIMS(pa->flags), pa->npoints);


        /* Get a pointer to nth point offset and zmflag */
        ptr=getPoint_internal(pa, n);
        zmflag=FLAGS_GET_ZM(pa->flags);

        /*
         * if input POINTARRAY has the M and NO Z,
         * we can issue a single memcpy
         */
        if ( zmflag == 1 )
        {
                memcpy(op, ptr, sizeof(POINT3DM));
                return 1;
        }

        /*
         * Otherwise copy the 2d part and
         * initialize M to NO_M_VALUE
         */
        memcpy(op, ptr, sizeof(POINT2D));

        /*
         * Then, if input has Z skip it and
         * copy next double, otherwise initialize
         * M to NO_M_VALUE
         */
        if ( zmflag == 3 )
        {
                ptr+=sizeof(POINT3DZ);
                memcpy(&(op->m), ptr, sizeof(double));
        }
        else
        {
                op->m=NO_M_VALUE;
        }

        return 1;
}

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