Sandro Santilli
ca544d0830
git-svn-id: http://svn.osgeo.org/postgis/trunk@15731 b70326c6-7e19-0410-871a-916f4a2858ee
65 lines
2.1 KiB
C
65 lines
2.1 KiB
C
/**********************************************************************
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*
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* PostGIS - Spatial Types for PostgreSQL
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* http://postgis.net
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*
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* PostGIS is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* PostGIS is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with PostGIS. If not, see <http://www.gnu.org/licenses/>.
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*
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**********************************************************************
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*
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* Copyright 2015 Daniel Baston <dbaston@gmail.com>
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*
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**********************************************************************/
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#ifndef _LWUNIONFIND
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#define _LWUNIONFIND 1
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#include "liblwgeom.h"
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typedef struct
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{
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uint32_t* clusters;
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uint32_t* cluster_sizes;
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uint32_t num_clusters;
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uint32_t N;
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} UNIONFIND;
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/* Allocate a UNIONFIND structure of capacity N */
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UNIONFIND* UF_create(uint32_t N);
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/* Release memory associated with UNIONFIND structure */
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void UF_destroy(UNIONFIND* uf);
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/* Identify the cluster id associated with specified component id */
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uint32_t UF_find(UNIONFIND* uf, uint32_t i);
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/* Get the size of the cluster associated with the specified component id */
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uint32_t UF_size(UNIONFIND* uf, uint32_t i);
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/* Merge the clusters that contain the two specified component ids */
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void UF_union(UNIONFIND* uf, uint32_t i, uint32_t j);
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/* Return an array of component ids, where components that are in the
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* same cluster are contiguous in the array */
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uint32_t* UF_ordered_by_cluster(UNIONFIND* uf);
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/* Replace the cluster ids in a UNIONFIND with sequential ids starting at one.
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* If is_in_cluster array is provided, it will be used to skip any indexes
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* that are not in a cluster.
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* */
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uint32_t* UF_get_collapsed_cluster_ids(UNIONFIND* uf, const char* is_in_cluster);
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#endif
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