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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Graph data structure.
*
* --
* Copyright (C) 2016 Cumulus Networks, Inc.
*/
#include <zebra.h>
#include "graph.h"
#include "memory.h"
#include "buffer.h"
DEFINE_MTYPE_STATIC(LIB, GRAPH, "Graph");
DEFINE_MTYPE_STATIC(LIB, GRAPH_NODE, "Graph Node");
struct graph *graph_new(void)
{
struct graph *graph = XCALLOC(MTYPE_GRAPH, sizeof(struct graph));
graph->nodes = vector_init(VECTOR_MIN_SIZE);
return graph;
}
void graph_delete_graph(struct graph *graph)
{
for (unsigned int i = vector_active(graph->nodes); i--; /**/)
graph_delete_node(graph, vector_slot(graph->nodes, i));
vector_free(graph->nodes);
XFREE(MTYPE_GRAPH, graph);
}
struct graph_node *graph_new_node(struct graph *graph, void *data,
void (*del)(void *))
{
struct graph_node *node =
XCALLOC(MTYPE_GRAPH_NODE, sizeof(struct graph_node));
node->from = vector_init(VECTOR_MIN_SIZE);
node->to = vector_init(VECTOR_MIN_SIZE);
node->data = data;
node->del = del;
vector_set(graph->nodes, node);
return node;
}
static void graph_vector_remove(vector v, unsigned int ix)
{
if (ix >= v->active)
return;
/* v->active is guaranteed >= 1 because ix can't be lower than 0
* and v->active is > ix. */
v->active--;
/* if ix == v->active--, we set the item to itself, then to NULL...
* still correct, no check necessary. */
v->index[ix] = v->index[v->active];
v->index[v->active] = NULL;
}
void graph_delete_node(struct graph *graph, struct graph_node *node)
{
if (!node)
return;
// an adjacent node
struct graph_node *adj;
// remove all edges from other nodes to us
for (unsigned int i = vector_active(node->from); i--; /**/) {
adj = vector_slot(node->from, i);
graph_remove_edge(adj, node);
}
// remove all edges from us to other nodes
for (unsigned int i = vector_active(node->to); i--; /**/) {
adj = vector_slot(node->to, i);
graph_remove_edge(node, adj);
}
// if there is a deletion callback, call it
if (node->del && node->data)
(*node->del)(node->data);
// free adjacency lists
vector_free(node->to);
vector_free(node->from);
// remove node from graph->nodes
for (unsigned int i = vector_active(graph->nodes); i--; /**/)
if (vector_slot(graph->nodes, i) == node) {
graph_vector_remove(graph->nodes, i);
break;
}
// free the node itself
XFREE(MTYPE_GRAPH_NODE, node);
}
struct graph_node *graph_add_edge(struct graph_node *from,
struct graph_node *to)
{
vector_set(from->to, to);
vector_set(to->from, from);
return to;
}
void graph_remove_edge(struct graph_node *from, struct graph_node *to)
{
// remove from from to->from
for (unsigned int i = vector_active(to->from); i--; /**/)
if (vector_slot(to->from, i) == from) {
graph_vector_remove(to->from, i);
break;
}
// remove to from from->to
for (unsigned int i = vector_active(from->to); i--; /**/)
if (vector_slot(from->to, i) == to) {
graph_vector_remove(from->to, i);
break;
}
}
struct graph_node *graph_find_node(struct graph *graph, void *data)
{
struct graph_node *g;
for (unsigned int i = vector_active(graph->nodes); i--; /**/) {
g = vector_slot(graph->nodes, i);
if (g->data == data)
return g;
}
return NULL;
}
bool graph_has_edge(struct graph_node *from, struct graph_node *to)
{
for (unsigned int i = vector_active(from->to); i--; /**/)
if (vector_slot(from->to, i) == to)
return true;
return false;
}
static void _graph_dfs(struct graph *graph, struct graph_node *start,
vector visited,
void (*dfs_cb)(struct graph_node *, void *), void *arg)
{
/* check that we have not visited this node */
for (unsigned int i = 0; i < vector_active(visited); i++) {
if (start == vector_slot(visited, i))
return;
}
/* put this node in visited stack */
vector_ensure(visited, vector_active(visited));
vector_set_index(visited, vector_active(visited), start);
/* callback */
dfs_cb(start, arg);
/* recurse into children */
for (unsigned int i = vector_active(start->to); i--; /**/) {
struct graph_node *c = vector_slot(start->to, i);
_graph_dfs(graph, c, visited, dfs_cb, arg);
}
}
void graph_dfs(struct graph *graph, struct graph_node *start,
void (*dfs_cb)(struct graph_node *, void *), void *arg)
{
vector visited = vector_init(VECTOR_MIN_SIZE);
_graph_dfs(graph, start, visited, dfs_cb, arg);
vector_free(visited);
}
#ifndef BUILDING_CLIPPY
void graph_dump_dot_default_print_cb(struct graph_node *gn, struct buffer *buf)
{
char nbuf[64];
for (unsigned int i = 0; i < vector_active(gn->to); i++) {
struct graph_node *adj = vector_slot(gn->to, i);
snprintf(nbuf, sizeof(nbuf), " n%p -> n%p;\n", gn, adj);
buffer_putstr(buf, nbuf);
}
}
char *graph_dump_dot(struct graph *graph, struct graph_node *start,
void (*pcb)(struct graph_node *, struct buffer *))
{
struct buffer *buf = buffer_new(0);
char *ret;
pcb = (pcb) ? pcb : graph_dump_dot_default_print_cb;
buffer_putstr(buf, "digraph {\n");
graph_dfs(graph, start, (void (*)(struct graph_node *, void *))pcb,
buf);
buffer_putstr(buf, "}\n");
ret = buffer_getstr(buf);
buffer_free(buf);
return ret;
}
#endif /* BUILDING_CLIPPY */
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