graph.c

#include <stdlib.h>
#include <string.h>

#include "graph.h"
#include "list.h"
#include "set.h"
void graph_init(Graph *graph, int (*match)(const void *key1, const void *key2), void (*destroy)(void *data))
{
    graph->vcount = 0;
    graph->ecount = 0;
    graph->match = match;
    graph->destroy = destroy;
    list_init(&graph->adjlists, NULL);
    return;
}

void graph_destroy(Graph *graph)
{
    AdjList *adjlist;

    // 移除每一个相邻的链表结构和链表
    while(list_size(&graph->adjlists) > 0) {
        if (list_rem_next(&graph->adjlists, NULL, (void **)&adjlist) == 0) {
            set_destroy(&adjlist->adjacent);

            if (graph->destroy != NULL) {
                graph->destroy(adjlist->vertex);
                free(adjlist);
            }
        }
    }

    list_destory(&graph->adjlists);
    memset(graph, 0 sizeof(Graph));
    return;
}

int graph_ins_vertex(Graph *graph, const void *data)
{
    ListElmt *element;
    AdjList *adjlist;
    int retval;

    // 不允许插入重复顶点
    for (element = list_head(&graph->adjlists); element != NULL; element = list_next(element)) {
        if (graph->match(data, ((AdjList *)list_data(element))->vertex)) {
            return 1;
        }
    }

    // 插入顶点
    if ((adjlist = (AdjList *)malloc(sizeof(AdjList))) == NULL) {
        return -1;
    }

    adjlist->vertex = (void *)data;
    set_init(&adjlist->adjacent, graph->match, NULL);

    if ((retval = list_ins_next(&graph->adjlists, list_tail(&graph->adjlists), adjlist)) != 0) {
        return retval;
    }

    graph->vcount++;
    return 0;
}

int graph_ins_edge(Graph *graph, const void *data1, const void *data2)
{
    ListElmt *element;
    int retval;
    // 不允许在图中，插入没有顶点的边缘元素
    for (element = list_head(&graph->adjlists); element != NULL; element = list_next(element)) {
        if (graph->match(data2, ((AdjList *)list_data(element))->vertex)) {
            break;
        }
    }

    if (element == NULL) {
        return -1;
    }

    for (element = list_head(&graph->adjlists); element != NULL; element = list_next(element)) {
        if (graph->match(data1, ((AdjList *)list_data(element))->vertex)) {
            break;
        }
    }

    if (element == NULL) {
        return -1;
    }

    // 插入第二个顶点在第一个顶点的相邻链表中
    if ((retval = set_insert(&((AdjList *)list_data(element))->adjacent, data2)) != 0) {
        return retval;
    }

    graph->ecount++;
    return 0;
}

int graph_rem_vertex(Graph *graph, void **data)
{
    ListElmt *element, *temp, *prev;
    AdjList *adjlist;
    int found;

    prev = NULL;
    found = 0;

    for (element = list_head(&graph->adjlists); element != NULL; list_next(element)) {

        // 如果在一个临近链表中，不允许移除其顶点
        if (set_is_member(&(AdjList *)list_data(element))->adjacent, *data) {
            return -1;
        }

        // 保持一个指针指向需要被移除的顶点
        if (graph->match(*data, ((AdjList *)list_data(element))->vertex)) {
            temp = element;
            found = 1;
        }

        // 保持一个指针在顶点被移除之前的顶点
        if (! found) {
            prev = element;
        }
    }

    // 如果顶点未被找到就返回
    if (! found) {
        return -1;
    }

    // 如果临近链表非空，则不允许移除其顶点
    if (set_size(&((AdjList *)list_data(temp))->adjacent) > 0) {
        return -1;
    }

    // 移除顶点
    if (list_rem_next(&graph->adjlists, prev, (void **)&adjlist) != 0) {
        return -1;
    }

    *data = adjlist->vertex;
    free(adjlist);
    graph->vcount--;
    return 0;
}

int graph_rem_edge(Graph *graph, void *data1, void **data2)
{
    ListElmt *element;

    // 定位第一个顶点的临近列表
    for (element = list_head(&graph->adjlists); element != NULL; element = list_next(element)) {
        if (graph->match(data1, ((AdjList *)list_data(element))->vertex)) {
            break;
        }
    }

    if (element == NULL) {
        return -1;
    }

    // 从第一个顶点的临近列表中移除第二个顶点
    if (set_remove(&((AdjList *)list_data(element))->adjacent, data2) != 0) {
        return -1;
    }

    // 为移除的边调整边的总数
    graph->ecount--;
    return 0;
}

int graph_adjlist(const Graph *graph, const void *data, AdjList **adjlist)
{
    ListElmt *element, *prev;

    prev = NULL;
    for (element = list_head(&graph->adjlists); element != NULL; element = list_next(element)) {
        if (graph->match(data, ((AdjList *)list_data(element))->vertex)) {
            break;
        }
        prev = element;
    }

    // 如果vertex没找到就返回
    if (element == NULL) {
        return -1;
    }

    *adjlist = list_data(element);
    return 0;
}

int graph_is_adjacent(const Graph *graph, const void *data1, const void *data2)
{
    ListElmt *element, *prev;

    prev = NULL;
    for (element = list_head(&graph->adjlists); element != NULL; element = list_next(element)) {
        if (graph->match(data1, ((AdjList *)list_data(element))->vertex)) {
            break;
        }
        prev = element;
    }

    // 如果vertex没找到就返回
    if (element == NULL) {
        return 0;
    }

    return set_is_member(&((AdjList *)list_data(element))->adjacent, data2);
}