jrk.h: update prev_offset in arena_resize, and always init the memory.

1 files changed, 3 insertions, 1 deletions

diff --git a/jrk.h b/jrk.h
index e65c1cc..bf3c970 100644
--- a/jrk.h
+++ b/jrk.h
@@ -494,14 +494,16 @@ jrk_arena_resize(jrk_Arena *arena, void *old, u64 old_size, u64 new_size)
 
     if (old == &arena->data[arena->prev_offset]) {
         result = old;
+        arena->prev_offset = arena->offset;
         arena->offset = new_size;
+        memset(&arena->data[arena->prev_offset], 0, new_size - old_size);
     } else {
         result = &arena->data[arena->offset];
         arena->prev_offset = arena->offset;
         arena->offset += new_size;
         if (arena->offset > arena->capacity) {
             jrk_errorv("jrk_arena_resize(%p, %p, %ld, %ld): arena resize requires %ld bytes but has a capacity of %ld bytes",
-                 (void *) arena, old, old_size, new_size, arena->offset, arena->capacity);
+                       (void *) arena, old, old_size, new_size, arena->offset, arena->capacity);
             return NULL;
         }
         memmove(result, old, old_size);