Add functions to get and set the watermark

1 files changed, 31 insertions, 0 deletions

diff --git a/memstack/test/memstack_test.c b/memstack/test/memstack_test.c
index 285cf46..5308be3 100644
--- a/memstack/test/memstack_test.c
+++ b/memstack/test/memstack_test.c
@@ -131,4 +131,35 @@ TEST_CASE(memstack_alloc_aligned) {
   memstack_del(&stack);
 }
 
+// Get and set the watermark.
+TEST_CASE(memstack_watermark) {
+  memstack stack = {0};
+  memstack_make(&stack, CAPACITY, nullptr);
+
+  // Allocate N/2 ints.
+  for (int i = 0; i < NUM_INTS / 2; ++i) {
+    const int* block = memstack_alloc(&stack, sizeof(int));
+    TEST_TRUE(block != nullptr);
+  }
+
+  const size_t watermark = memstack_watermark(&stack);
+
+  // Allocate the remaining N/2 ints.
+  for (int i = 0; i < NUM_INTS / 2; ++i) {
+    const int* block = memstack_alloc(&stack, sizeof(int));
+    TEST_TRUE(block != nullptr);
+  }
+
+  // Now reset the watermark halfway through.
+  memstack_set_watermark(&stack, watermark);
+
+  // Allocate the remaining N/2 ints (again).
+  for (int i = 0; i < NUM_INTS / 2; ++i) {
+    const int* block = memstack_alloc(&stack, sizeof(int));
+    TEST_TRUE(block != nullptr);
+  }
+
+  memstack_del(&stack);
+}
+
 int main() { return 0; }