1 files changed, 37 insertions, 0 deletions
diff --git a/lib/ccan/asearch/asearch.h b/lib/ccan/asearch/asearch.h
new file mode 100644
index 00000000000..d252284e7d8
--- /dev/null
+++ b/lib/ccan/asearch/asearch.h
@@ -0,0 +1,37 @@
+#ifndef CCAN_ASEARCH_H
+#define CCAN_ASEARCH_H
+#include <stdlib.h>
+#include <ccan/typesafe_cb/typesafe_cb.h>
+
+/**
+ * asearch - search an array of elements
+ * @key: pointer to item being searched for
+ * @base: pointer to data to sort
+ * @num: number of elements
+ * @cmp: pointer to comparison function
+ *
+ * This function does a binary search on the given array.  The
+ * contents of the array should already be in ascending sorted order
+ * under the provided comparison function.
+ *
+ * Note that the key need not have the same type as the elements in
+ * the array, e.g. key could be a string and the comparison function
+ * could compare the string with the struct's name field.  However, if
+ * the key and elements in the array are of the same type, you can use
+ * the same comparison function for both sort() and asearch().
+ */
+#if HAVE_TYPEOF
+#define asearch(key, base, num, cmp)					\
+	((__typeof__(*(base))*)(bsearch((key), (base), (num), sizeof(*(base)), \
+		typesafe_cb_cast(int (*)(const void *, const void *),	\
+				 int (*)(const __typeof__(*(key)) *,	\
+					 const __typeof__(*(base)) *),	\
+				 (cmp)))))
+
+#else
+#define asearch(key, base, num, cmp)				\
+	(bsearch((key), (base), (num), sizeof(*(base)),		\
+		 (int (*)(const void *, const void *))(cmp)))
+#endif
+
+#endif /* CCAN_ASEARCH_H */