1 files changed, 73 insertions, 0 deletions
diff --git a/cached.c b/cached.c
new file mode 100644
index 0000000..8174cda
--- /dev/null
+++ b/cached.c
@@ -0,0 +1,73 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "cached.h"
+
+static size_t object_size;
+static size_t max_cached;
+static size_t num_cached;
+static void **cache;
+
+int
+ca_setup(size_t osize, size_t csize)
+{
+	/* TODO allow osize == 0 following malloc? */
+	if (osize == 0 || csize == 0) {
+		return -1;
+	}
+
+	cache = calloc(csize, sizeof(*cache));
+	if (cache == NULL) {
+		return -2;
+	}
+
+	object_size = osize;
+	max_cached = csize;
+	num_cached = 0;
+
+	return 0;
+}
+
+void *
+ca_alloc(void)
+{
+	assert(cache != NULL);
+
+	if (num_cached > 0) {
+		void *object = cache[--num_cached];
+		return object;
+	}
+
+	return calloc(1, object_size);
+}
+
+void
+ca_free(void *object)
+{
+	assert(cache != NULL);
+
+	if (object == NULL) {
+		/* free(3) also does nothing for NULL */
+		return;
+	}
+
+	if (num_cached < max_cached) {
+		cache[num_cached++] = object;
+		/* memset here to catch dangling references */
+		memset(object, 0, object_size);
+		return;
+	}
+
+	free(object);
+}
+
+void
+ca_cleanup(void)
+{
+	for (size_t i = 0; i < num_cached; i++) {
+		free(cache[i]);
+	}
+	free(cache);
+	cache = NULL;
+}