fix bug in arena_realloc()

i don't remember what it was but it broke select_file_in()

1 files changed, 8 insertions, 3 deletions

diff --git a/arena.h b/arena.h
index a5cc3dd..89c92d6 100644
--- a/arena.h
+++ b/arena.h
@@ -77,9 +77,14 @@ void *arena_alloc(Arena *a, size_t sz, size_t align) {
 }
 
 void *arena_realloc(Arena *a, void *old, size_t oldsz, size_t newsz, size_t align) {
-	if (old == a->beg - oldsz) a->beg = old;
-	else if (old) memcpy(a->beg, old, oldsz);
-	return arena_alloc(a, newsz, align);
+	if (old == a->beg - oldsz) {
+		a->beg = (char*)old + newsz;
+		return old;
+	} else {
+		void *p = arena_alloc(a, newsz, align);
+		if (old) memcpy(p, old, oldsz);
+		return p;
+	}
 }
 
 #endif