From dc833bcc6d4db6f1aed7c2c3c3e4ef3f508fda5d Mon Sep 17 00:00:00 2001
From: ChanTsune <41658782+ChanTsune@users.noreply.github.com>
Date: Sat, 7 Oct 2023 17:07:28 +0900
Subject: [PATCH] :bug: fix #71 avoid free null pointer

---
 liblzma-sys/src/wasm_shim.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/liblzma-sys/src/wasm_shim.rs b/liblzma-sys/src/wasm_shim.rs
index a216e75c..29bafc5c 100644
--- a/liblzma-sys/src/wasm_shim.rs
+++ b/liblzma-sys/src/wasm_shim.rs
@@ -19,6 +19,9 @@ pub extern "C" fn rust_lzma_wasm_shim_calloc(nmemb: usize, size: usize) -> *mut
 
 #[no_mangle]
 pub unsafe extern "C" fn rust_lzma_wasm_shim_free(ptr: *mut c_void) {
+    if ptr == std::ptr::null_mut() {
+        return;
+    }
     // layout is not actually used
     let layout = Layout::from_size_align_unchecked(1, 1);
     dealloc(ptr.cast(), layout);