From 8e3b4411ed0d20990e907d74f32cc68e6a3c72be Mon Sep 17 00:00:00 2001
From: cozis <heibyob@gmail.com>
Date: Tue, 19 Apr 2022 01:30:32 +0200
Subject: [PATCH] fixed allocator use after free and added some somments

---
 xjson.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/xjson.c b/xjson.c
index 753898b..6d19887 100644
--- a/xjson.c
+++ b/xjson.c
@@ -53,9 +53,11 @@ xj_alloc *xj_alloc_using(void *mem, int size, int ext, void (*free)(void*))
 
 void xj_alloc_del(xj_alloc *alloc)
 {
-    if(alloc->free != NULL)
-        alloc->free(alloc);
-
+    // Free all of the allocator's chunks,
+    // with exception of the first one,
+    // which is allocated with the allocator's
+    // header and must be deallocated with
+    // the user-provided callback-
     chunk_t *curr = alloc->tail;
     while(curr->prev != NULL)
     {
@@ -63,6 +65,11 @@ void xj_alloc_del(xj_alloc *alloc)
         free(curr);
         curr = prev;
     }
+
+    // Free the allocator header and first
+    // chunk.
+    if(alloc->free != NULL)
+        alloc->free(alloc);
 }
 
 unsigned long long next_aligned(unsigned long long n)