getPoint3dm_p()

int getPoint3dm_p	(	const POINTARRAY *	pa,
		uint32_t	n,
		POINT3DM *	op
	)

Definition at line 268 of file lwgeom_api.c.

{
        uint8_t *ptr;
        int zmflag;
 
        if (!pa)
        {
                lwerror("%s [%d] NULL POINTARRAY input", __FILE__, __LINE__);
                return LW_FALSE;
        }
 
        if (n >= pa->npoints)
        {
                lwerror("%s [%d] called with n=%d and npoints=%d", __FILE__, __LINE__, n, pa->npoints);
                return LW_FALSE;
        }
 
        /* 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 LW_TRUE;
        }
 
        /*
         * 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 LW_TRUE;
}

References POINTARRAY::flags, FLAGS_GET_ZM, getPoint_internal(), LW_FALSE, LW_TRUE, lwerror(), POINT3DM::m, NO_M_VALUE, and POINTARRAY::npoints.

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

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