lwgeom_btree.c

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/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 *
 * PostGIS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * PostGIS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PostGIS.  If not, see <http://www.gnu.org/licenses/>.
 *
 **********************************************************************
 *
 * Copyright (C) 2010 Olivier Courtin <olivier.courtin@oslandia.com>
 * Copyright (C) 2010 Mark Cave-Ayland <mark.cave-ayland@siriusit.co.uk>
 * Copyright (C) 2009-2011 Paul Ramsey <pramsey@cleverelephant.ca>
 *
 **********************************************************************/
 
 
#include "postgres.h"
#include "fmgr.h"
#include "access/hash.h"
#include "utils/geo_decls.h"
#include "utils/sortsupport.h" /* SortSupport */
 
#include "../postgis_config.h"
#include "liblwgeom.h"
#include "lwgeom_pg.h"
 
#include <math.h>
#include <float.h>
#include <string.h>
#include <stdio.h>
 
Datum lwgeom_lt(PG_FUNCTION_ARGS);
Datum lwgeom_le(PG_FUNCTION_ARGS);
Datum lwgeom_eq(PG_FUNCTION_ARGS);
Datum lwgeom_ge(PG_FUNCTION_ARGS);
Datum lwgeom_gt(PG_FUNCTION_ARGS);
Datum lwgeom_cmp(PG_FUNCTION_ARGS);
 
PG_FUNCTION_INFO_V1(lwgeom_lt);
Datum lwgeom_lt(PG_FUNCTION_ARGS)
{
        GSERIALIZED *g1 = PG_GETARG_GSERIALIZED_P(0);
        GSERIALIZED *g2 = PG_GETARG_GSERIALIZED_P(1);
        int cmp = gserialized_cmp(g1, g2);
        PG_FREE_IF_COPY(g1, 0);
        PG_FREE_IF_COPY(g2, 1);
        if (cmp < 0)
                PG_RETURN_BOOL(true);
        else
                PG_RETURN_BOOL(false);
}
 
PG_FUNCTION_INFO_V1(lwgeom_le);
Datum lwgeom_le(PG_FUNCTION_ARGS)
{
        GSERIALIZED *g1 = PG_GETARG_GSERIALIZED_P(0);
        GSERIALIZED *g2 = PG_GETARG_GSERIALIZED_P(1);
        int cmp = gserialized_cmp(g1, g2);
        PG_FREE_IF_COPY(g1, 0);
        PG_FREE_IF_COPY(g2, 1);
        if (cmp <= 0)
                PG_RETURN_BOOL(true);
        else
                PG_RETURN_BOOL(false);
}
 
PG_FUNCTION_INFO_V1(lwgeom_eq);
Datum lwgeom_eq(PG_FUNCTION_ARGS)
{
        GSERIALIZED *g1 = PG_GETARG_GSERIALIZED_P(0);
        GSERIALIZED *g2 = PG_GETARG_GSERIALIZED_P(1);
        int cmp = gserialized_cmp(g1, g2);
        PG_FREE_IF_COPY(g1, 0);
        PG_FREE_IF_COPY(g2, 1);
        if (cmp == 0)
                PG_RETURN_BOOL(true);
        else
                PG_RETURN_BOOL(false);
}
 
PG_FUNCTION_INFO_V1(lwgeom_ge);
Datum lwgeom_ge(PG_FUNCTION_ARGS)
{
        GSERIALIZED *g1 = PG_GETARG_GSERIALIZED_P(0);
        GSERIALIZED *g2 = PG_GETARG_GSERIALIZED_P(1);
        int cmp = gserialized_cmp(g1, g2);
        PG_FREE_IF_COPY(g1, 0);
        PG_FREE_IF_COPY(g2, 1);
        if (cmp >= 0)
                PG_RETURN_BOOL(true);
        else
                PG_RETURN_BOOL(false);
}
 
PG_FUNCTION_INFO_V1(lwgeom_gt);
Datum lwgeom_gt(PG_FUNCTION_ARGS)
{
        GSERIALIZED *g1 = PG_GETARG_GSERIALIZED_P(0);
        GSERIALIZED *g2 = PG_GETARG_GSERIALIZED_P(1);
        int cmp = gserialized_cmp(g1, g2);
        PG_FREE_IF_COPY(g1, 0);
        PG_FREE_IF_COPY(g2, 1);
        if (cmp > 0)
                PG_RETURN_BOOL(true);
        else
                PG_RETURN_BOOL(false);
}
 
PG_FUNCTION_INFO_V1(lwgeom_cmp);
Datum lwgeom_cmp(PG_FUNCTION_ARGS)
{
        GSERIALIZED *g1 = PG_GETARG_GSERIALIZED_P(0);
        GSERIALIZED *g2 = PG_GETARG_GSERIALIZED_P(1);
        int ret = gserialized_cmp(g1, g2);
        PG_FREE_IF_COPY(g1, 0);
        PG_FREE_IF_COPY(g2, 1);
        PG_RETURN_INT32(ret);
}
 
PG_FUNCTION_INFO_V1(lwgeom_hash);
Datum lwgeom_hash(PG_FUNCTION_ARGS)
{
        GSERIALIZED *g1 = PG_GETARG_GSERIALIZED_P(0);
 
        int32_t hval = gserialized_hash(g1);
        PG_FREE_IF_COPY(g1, 0);
        PG_RETURN_INT32(hval);
}
 
static int
lwgeom_cmp_abbrev(Datum x, Datum y, SortSupport ssup)
{
        /* Empty is a special case */
        if (x == 0 || y == 0 || x == y)
                return 0; /* 0 means "ask bigger comparator" and not equality*/
        else if (x > y)
                return 1;
        else
                return -1;
}
 
static int
lwgeom_cmp_full(Datum x, Datum y, SortSupport ssup)
{
        GSERIALIZED *g1 = (GSERIALIZED *)PG_DETOAST_DATUM(x);
        GSERIALIZED *g2 = (GSERIALIZED *)PG_DETOAST_DATUM(y);
        int ret = gserialized_cmp(g1, g2);
        POSTGIS_FREE_IF_COPY_P(g1, x);
        POSTGIS_FREE_IF_COPY_P(g2, y);
        return ret;
}
 
static bool
lwgeom_abbrev_abort(int memtupcount, SortSupport ssup)
{
        return LW_FALSE;
}
 
static Datum
lwgeom_abbrev_convert(Datum original, SortSupport ssup)
{
        GSERIALIZED *g = (GSERIALIZED *)PG_DETOAST_DATUM(original);
        uint64_t hash = gserialized_get_sortable_hash(g);
        POSTGIS_FREE_IF_COPY_P(g, original);
        return hash;
}
 
/*
 * Sort support strategy routine
 */
PG_FUNCTION_INFO_V1(lwgeom_sortsupport);
Datum lwgeom_sortsupport(PG_FUNCTION_ARGS)
{
        SortSupport ssup = (SortSupport)PG_GETARG_POINTER(0);
 
        ssup->comparator = lwgeom_cmp_full;
        ssup->ssup_extra = NULL;
        /* Enable sortsupport only on 64 bit Datum */
        if (ssup->abbreviate && sizeof(Datum) == 8)
        {
                ssup->comparator = lwgeom_cmp_abbrev;
                ssup->abbrev_converter = lwgeom_abbrev_convert;
                ssup->abbrev_abort = lwgeom_abbrev_abort;
                ssup->abbrev_full_comparator = lwgeom_cmp_full;
        }
 
        PG_RETURN_VOID();
}