h3_vertexGraph.h

/*
 * Copyright 2017 Uber Technologies, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/** @file vertexGraph.h
 * @brief   Data structure for storing a graph of vertices
 */

#ifndef VERTEX_GRAPH_H
#define VERTEX_GRAPH_H

#include <stdint.h>
#include <stdlib.h>
#include "h3_geoCoord.h"

/** @struct VertexNode
 *  @brief A single node in a vertex graph, part of a linked list
 */
typedef struct VertexNode VertexNode;
struct VertexNode {
    GeoCoord from;
    GeoCoord to;
    VertexNode* next;
};

/** @struct VertexGraph
 *  @brief A data structure to store a graph of vertices
 */
typedef struct {
    VertexNode** buckets;
    int numBuckets;
    int size;
    int res;
} VertexGraph;

void initVertexGraph(VertexGraph* graph, int numBuckets, int res);

void destroyVertexGraph(VertexGraph* graph);

VertexNode* addVertexNode(VertexGraph* graph, const GeoCoord* fromVtx,
                          const GeoCoord* toVtx);

int removeVertexNode(VertexGraph* graph, VertexNode* node);

VertexNode* findNodeForEdge(const VertexGraph* graph, const GeoCoord* fromVtx,
                            const GeoCoord* toVtx);

VertexNode* findNodeForVertex(const VertexGraph* graph,
                              const GeoCoord* fromVtx);

VertexNode* firstVertexNode(const VertexGraph* graph);

// Internal functions
uint32_t _hashVertex(const GeoCoord* vertex, int res, int numBuckets);
void _initVertexNode(VertexNode* node, const GeoCoord* fromVtx,
                     const GeoCoord* toVtx);

#endif