cu_minimum_bounding_circle.c

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/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 * Copyright 2015 Daniel Baston
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU General Public Licence. See the COPYING file.
 *
 **********************************************************************/

#include "CUnit/Basic.h"
#include "cu_tester.h"
#include "../liblwgeom_internal.h"

static void mbc_test(LWGEOM* g)
{
        LWBOUNDINGCIRCLE* result = lwgeom_calculate_mbc(g);
        CU_ASSERT_TRUE(result != NULL);

        LWPOINTITERATOR* it = lwpointiterator_create(g);

        POINT2D p;
        POINT4D p4;
        while (lwpointiterator_next(it, &p4))
        {
                p.x = p4.x;
                p.y = p4.y;

                /* We need to store the distance in a variable before the assert so that
                 * it is rounded from its 80-bit representation (on x86) down to 64 bits.
                 * */
                volatile double d = distance2d_pt_pt(result->center, &p);

                CU_ASSERT_TRUE(d <= result->radius);
        }

        lwboundingcircle_destroy(result);
        lwpointiterator_destroy(it);
}

static void basic_test(void)
{
        uint32_t i;

        char* inputs[] =
        {
                "POLYGON((26426 65078,26531 65242,26075 65136,26096 65427,26426 65078))",
                "POINT (17 253)",
                "TRIANGLE ((0 0, 10 0, 10 10, 0 0))",
                "LINESTRING (17 253, -44 28, 33 11, 26 44)",
                "MULTIPOINT ((0 0), (0 0), (0 0), (0 0))",
                "POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))",
                "LINESTRING (-48546889 37039202, -37039202 -48546889)"
        };

        for (i = 0; i < sizeof(inputs)/sizeof(LWGEOM*); i++)
        {
                LWGEOM* input = lwgeom_from_wkt(inputs[i], LW_PARSER_CHECK_NONE);
                mbc_test(input);
                lwgeom_free(input);
        }

}

static void test_empty(void)
{
        LWGEOM* input = lwgeom_from_wkt("POINT EMPTY", LW_PARSER_CHECK_NONE);

        LWBOUNDINGCIRCLE* result = lwgeom_calculate_mbc(input);
        CU_ASSERT_TRUE(result == NULL);

        lwgeom_free(input);
}

/*
 ** Used by test harness to register the tests in this file.
 */
void minimum_bounding_circle_suite_setup(void);
void minimum_bounding_circle_suite_setup(void)
{
        CU_pSuite suite = CU_add_suite("minimum_bounding_circle", NULL, NULL);
        PG_ADD_TEST(suite, basic_test);
        PG_ADD_TEST(suite, test_empty);
}