Make the stack dynamic

1 files changed, 9 insertions, 1 deletions

diff --git a/stack.c b/stack.c
index d719cb3..8b4c478 100644
--- a/stack.c
+++ b/stack.c
@@ -6,12 +6,17 @@
 
 PositionStack ps_new(void) {
     PositionStack ps;
+    ps.capacity = STACK_INITIAL_CAPACITY;
+    ps.arr = malloc(sizeof(Position) * ps.capacity);
     ps.top = 0;
     return ps;
 }
 
 int ps_push(PositionStack *ps, Position pos) {
-    if (ps->top >= STACK_SIZE) return -1; /* FIXME: do a dynamic stack */
+    if (ps->top >= ps->capacity) {
+        ps->capacity *= STACK_SIZE_COEFFICIENT;
+        if ((ps->arr = realloc(ps->arr, sizeof(Position) * ps->capacity)) == NULL) return -1;
+    }
     ps->arr[ps->top] = pos;
     ps->top += 1;
     return 0;
@@ -28,3 +33,6 @@ Position ps_peek(PositionStack ps) {
     return ps.arr[ps.top - 1];
 }
 
+void ps_free(PositionStack ps) {
+    free(ps.arr);
+}