implement enough for fibonacci

1 files changed, 13 insertions, 4 deletions

diff --git a/src/vec.h b/src/vec.h
index e998e27..7e6b5be 100644
--- a/src/vec.h
+++ b/src/vec.h
@@ -33,11 +33,12 @@ struct vec {
 
 static inline struct vec vec_create(size_t ns)
 {
+	const size_t s = 8;
 	return (struct vec) {
 		       .n = 0,
-		       .s = 1,
+		       .s = s,
 		       .ns = ns,
-		       .buf = malloc(ns),
+		       .buf = malloc(s * ns),
 	};
 }
 
@@ -98,8 +99,16 @@ static inline void vec_reserve(struct vec *v, size_t n)
 		return;
 
 	v->n = n;
-	v->s = n;
-	v->buf = realloc(v->buf, v->s * v->ns);
+	if (v->s < v->n) {
+		v->s *= 2;
+		v->buf = realloc(v->buf, v->s * v->ns);
+	}
+}
+
+static inline void vec_shrink(struct vec *v, size_t n)
+{
+	assert(v->n >= n);
+	v->n = n;
 }
 
 #endif /* VEC_H */