Reorganize code into library for reuse

lib/set.c

@@ -0,0 +1,47 @@
+#include <stdlib.h>
+#include "set.h"
+
+struct node_set {
+    size_t width, height;
+    size_t size;
+    bool** nodes;
+};
+
+struct node_set* node_set_new(size_t width, size_t height) {
+    struct node_set* result = malloc(sizeof(struct node_set));
+    result->nodes = calloc(height, sizeof(bool*));
+    for (size_t i = 0; i < height; i++) {
+        result->nodes[i] = calloc(width, sizeof(bool));
+        for (size_t j = 0; j < width; j++) {
+            result->nodes[i][j] = false;
+        }
+    }
+    result->width = width;
+    result->height = height;
+    result->size = 0;
+    return result;
+}
+
+void node_set_add(struct node_set* s, size_t x, size_t y) {
+    s->nodes[y][x] = true;
+    s->size++;
+}
+
+bool node_set_contains(struct node_set const* s, size_t x, size_t y) {
+    return s->nodes[y][x];
+}
+
+void node_set_free(struct node_set* s) {
+    for (size_t i = 0; i < s->height; i++) {
+        free(s->nodes[i]);
+        s->nodes[i] = NULL;
+    }
+    free(s->nodes);
+    s->nodes = NULL;
+    s->width = s->height = s->size = 0;
+    free(s);
+}
+
+size_t node_set_size(struct node_set const* s) {
+    return s->size;
+}