2 files changed, 16 insertions, 8 deletions

diff --git a/mem/src/mem.c b/mem/src/mem.c
index 9169a9f..70648c9 100644
--- a/mem/src/mem.c
+++ b/mem/src/mem.c
@@ -57,14 +57,16 @@ void mem_del_(Memory* mem) {
 
 void mem_clear_(Memory* mem) {
   assert(mem);
-  mem->num_used_blocks = 0;
-  mem->next_free_chunk = 0;
-  memset(mem->blocks, 0, mem->num_blocks * mem->block_size_bytes);
-  memset(mem->chunks, 0, mem->num_blocks * sizeof(Chunk));
-
-  // Initialize the head as one large free chunk.
-  Chunk* head      = &mem->chunks[0];
-  head->num_blocks = mem->num_blocks;
+  if (mem->num_blocks > 0) {
+    mem->num_used_blocks = 0;
+    mem->next_free_chunk = 0;
+    memset(mem->blocks, 0, mem->num_blocks * mem->block_size_bytes);
+    memset(mem->chunks, 0, mem->num_blocks * sizeof(Chunk));
+
+    // Initialize the head as one large free chunk.
+    Chunk* head      = &mem->chunks[0];
+    head->num_blocks = mem->num_blocks;
+  }
 }
 
 void* mem_alloc_(Memory* mem, size_t num_blocks) {
diff --git a/mem/test/mem_test.c b/mem/test/mem_test.c
index a8d482f..52ce5a9 100644
--- a/mem/test/mem_test.c
+++ b/mem/test/mem_test.c
@@ -32,6 +32,12 @@ TEST_CASE(mem_create_dyn) {
   mem_make_dyn(&mem, NUM_BLOCKS, sizeof(int));
 }
 
+// Clear an uninitialized allocator.
+TEST_CASE(mem_clear_uninitialized) {
+  test_mem mem = {0};
+  mem_clear(&mem);
+}
+
 // Allocate N chunks of 1 block each.
 TEST_CASE(mem_fully_allocate) {
   test_mem mem;