Graph implementation and correct parsing of edges

generator.c

@@ -6,11 +6,26 @@
  */
 
 #include "common.h"
+#include <limits.h>
 
 static const char *pname;
 
 struct sigaction sa;
 
+struct AdjListNode {
+	int dest;
+	struct AdjListNode *next;
+};
+
+struct AdjList {
+	struct AdjListNode *head;
+};
+
+struct Graph {
+	int V;
+	struct AdjList *array;
+};
+
 static volatile sig_atomic_t quit = 0;
 
 static void sig_handler(int signum)
@@ -27,6 +42,128 @@ void usage(void)
 	exit(EXIT_FAILURE);
 }
 
+struct AdjListNode *newAdjListNode(int dest)
+{
+	struct AdjListNode *newNode = malloc(sizeof(struct AdjListNode));
+	newNode->dest = dest;
+	newNode->next = NULL;
+	return newNode;
+}
+
+struct Graph *createGraph(int V)
+{
+	struct Graph *graph = malloc(sizeof(struct Graph));
+	graph->V = V;
+
+	graph->array = malloc(V * sizeof(struct AdjList));
+
+	for (int i = 0; i < V; i++)
+		graph->array[i].head = NULL;
+	
+	return graph;
+}
+
+void addEdge(struct Graph *graph, int src, int dest)
+{
+	struct AdjListNode *newNode = newAdjListNode(dest);
+	newNode->next = graph->array[src].head;
+	graph->array[src].head = newNode;
+}
+
+int strToInt(char *str)
+{
+	char *endptr;
+	long val;
+
+	val = strtol(str, &endptr, 10);
+	if ((errno == ERANGE && (val == LONG_MAX || val == LONG_MIN)) ||
+	    (errno != 0)) {
+		perror(pname);
+		return -2;
+	}
+	if (val < INT_MIN || val > INT_MAX) {
+		fprintf(stderr, "[%s] Please choose a smaller node: ", pname);
+		return -1;
+	}
+	
+	return (int) val;
+}
+
+struct Graph *parse(int argc, char *argv[])
+{
+	char *edge;
+	char *token;
+	char *str;
+	int V = 0;
+	int src;
+	int dest;
+	int edges_counter = 0;
+	int edges[(argc - 1) * 2];
+
+	for (int i = 1; i < argc; i++) {
+		edge = argv[i];
+		str = strdup(edge);
+		int count = 0;
+		while ((token = strsep(&str, "-"))) {
+			if (count == 0) {
+				src = strToInt(token);
+				edges[edges_counter] = src;
+				edges_counter++;
+				if (src > V)
+					V = src;
+			}
+			if (count == 1) {
+				dest = strToInt(token);
+				edges[edges_counter] = dest;
+				edges_counter++;
+				if (dest > V)
+					V = dest;
+			}
+			if (count > 1) {
+				fprintf(stderr, "[%s] An edge consists of two "
+						"nodes separated by a dash\n", pname);
+				free(str);
+				exit(EXIT_FAILURE);
+			}
+			switch (src) {
+			case -2:
+				free(str);
+				exit(EXIT_FAILURE);
+				break;
+			case -1:
+				fprintf(stderr, "%s\n", edge);
+				free(str);
+				exit(EXIT_FAILURE);
+				break;
+			default:
+				break;
+			}
+
+			count++;
+		}
+	}
+
+	struct Graph *graph = createGraph(V+1);
+	for (int i = 0; i < (sizeof(edges) / sizeof(int)); i+=2) {
+		addEdge(graph, edges[i], edges[i+1]);
+	}
+
+	return graph;
+}
+
+void printGraph(struct Graph *graph)
+{
+	for (int v = 0; v < graph->V; v++) {
+		struct AdjListNode* pCrawl = graph->array[v].head;
+		printf("\n Adjacency list of vertex %d\n head ", v);
+		while (pCrawl) {
+			printf("-> %d", pCrawl->dest);
+			pCrawl = pCrawl->next;
+		}
+		printf("\n");
+	}
+}
+
 int main(int argc, char *argv[])
 {
 	if (argc == 1)
@@ -40,7 +177,9 @@ int main(int argc, char *argv[])
 	sigaction(SIGTERM, &sa, NULL);
 
 	while (quit == 0) {
-
+		struct Graph *graph = parse(argc, argv);
+		printGraph(graph);
+		break;
 	}
 
 	return 0;