Track checkpoint levels

src/arena.c

@@ -35,6 +35,7 @@ Arena *arena_alloc_(const ArenaParams *params)
     arena->pos      = ARENA_HEADER_SZ;
     arena->base_pos = 0;
     arena->prev     = NULL;
+    arena->checkpoint_level = 0;
 
     return arena;
 }
@@ -113,7 +114,7 @@ ArenaCheckPoint arena_temp_begin(Arena *arena)
     ArenaCheckPoint checkpoint = {};
     checkpoint.arena = arena;
     checkpoint.absolute_pos = arena_absolute_pos(arena);
-
+    arena->checkpoint_level++;
     return checkpoint;
 }
 
@@ -121,4 +122,11 @@ void arena_temp_end(ArenaCheckPoint *checkpoint)
 {
     Arena *arena = checkpoint->arena;
     arena_pop_to(arena, checkpoint->absolute_pos);
+    Assert(arena->checkpoint_level > 0);
+    arena->checkpoint_level--;
+}
+
+void arena_reset(Arena *arena)
+{
+    arena_pop_to(arena, 0);
 }