1 files changed, 115 insertions, 0 deletions
diff --git a/ccan/take/take.c b/ccan/take/take.c
new file mode 100644
index 0000000..c628aac
--- /dev/null
+++ b/ccan/take/take.c
@@ -0,0 +1,115 @@
+/* CC0 (Public domain) - see LICENSE file for details */
+#include <ccan/take/take.h>
+#include <ccan/likely/likely.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static const void **takenarr;
+static const char **labelarr;
+static size_t max_taken, num_taken;
+static size_t allocfail;
+static void (*allocfailfn)(const void *p);
+
+void *take_(const void *p, const char *label)
+{
+	/* Overallocate: it's better than risking calloc returning NULL! */
+	if (unlikely(label && !labelarr))
+		labelarr = calloc(max_taken+1, sizeof(*labelarr));
+
+	if (unlikely(num_taken == max_taken)) {
+		const void **new;
+
+		new = realloc(takenarr, sizeof(*takenarr) * (max_taken+1));
+		if (unlikely(!new)) {
+			if (allocfailfn) {
+				allocfail++;
+				allocfailfn(p);
+				return NULL;
+			}
+			/* Otherwise we leak p. */
+			return (void *)p;
+		}
+		takenarr = new;
+		/* Once labelarr is set, we maintain it. */
+		if (labelarr)
+			labelarr = realloc(labelarr,
+					   sizeof(*labelarr) * (max_taken+1));
+		max_taken++;
+	}
+	if (unlikely(labelarr))
+		labelarr[num_taken] = label;
+	takenarr[num_taken++] = p;
+
+	return (void *)p;
+}
+
+static size_t find_taken(const void *p)
+{
+	size_t i;
+
+	for (i = 0; i < num_taken; i++) {
+		if (takenarr[i] == p)
+			return i+1;
+	}
+	return 0;
+}
+
+bool taken(const void *p)
+{
+	size_t i;
+
+	if (!p && unlikely(allocfail)) {
+		allocfail--;
+		return true;
+	}
+
+	i = find_taken(p);
+	if (!i)
+		return false;
+
+	memmove(&takenarr[i-1], &takenarr[i],
+		(--num_taken - (i - 1))*sizeof(takenarr[0]));
+	return true;
+}
+
+bool is_taken(const void *p)
+{
+	if (!p && unlikely(allocfail))
+		return true;
+
+	return find_taken(p) > 0;
+}
+
+const char *taken_any(void)
+{
+	static char pointer_buf[32];
+
+	if (num_taken == 0)
+		return NULL;
+
+	/* We're *allowed* to have some with labels, some without. */
+	if (labelarr) {
+		size_t i;
+		for (i = 0; i < num_taken; i++)
+			if (labelarr[i])
+				return labelarr[i];
+	}
+
+	sprintf(pointer_buf, "%p", takenarr[0]);
+	return pointer_buf;
+}
+
+void take_cleanup(void)
+{
+	max_taken = num_taken = 0;
+	free(takenarr);
+	takenarr = NULL;
+	free(labelarr);
+	labelarr = NULL;
+}
+
+void take_allocfail(void (*fn)(const void *p))
+{
+	allocfailfn = fn;
+}