From 51d7091874907b481be2ae20a346a6215ae67390 Mon Sep 17 00:00:00 2001
From: Nicolas Cornu <nicolac76@yahoo.fr>
Date: Tue, 18 Oct 2016 10:37:56 +0200
Subject: [PATCH] Add a bsearch for list

---
 common/list.c  | 15 +++++++++++++++
 include/list.h |  7 +++++++
 2 files changed, 22 insertions(+)

diff --git a/common/list.c b/common/list.c
index d57234e3..ffe8b177 100644
--- a/common/list.c
+++ b/common/list.c
@@ -129,3 +129,18 @@ void list_stable_sort(list_t *list, int compare(const void *a, const void *b)) {
 		list_inplace_sort(list, 0, list->length - 1, compare);
 	}
 }
+
+void *list_bsearch(list_t *list, int compare(const void *a, const void *b), const void *data) {
+	return bsearch(data, list->items, list->length, sizeof(void*), compare);
+}
+
+int list_binary_find(list_t *list, int compare(const void *item, const void *data), const void *data, size_t size) {
+	if (list->length == 0) {
+		return -1;
+	}
+	void **item = list_bsearch(list, compare, data);
+	if (item != NULL)
+		return (item-list->items) / size;
+	else
+		return -1;
+}
diff --git a/include/list.h b/include/list.h
index f478b6bb..0e82dba2 100644
--- a/include/list.h
+++ b/include/list.h
@@ -1,6 +1,8 @@
 #ifndef _SWAY_LIST_H
 #define _SWAY_LIST_H
 
+#include <stddef.h>
+
 typedef struct {
 	int capacity;
 	int length;
@@ -22,4 +24,9 @@ void list_qsort(list_t *list, int compare(const void *left, const void *right));
 int list_seq_find(list_t *list, int compare(const void *item, const void *cmp_to), const void *cmp_to);
 // stable sort since qsort is not guaranteed to be stable
 void list_stable_sort(list_t *list, int compare(const void *a, const void *b));
+// binary search
+void *list_bsearch(list_t *list, int compare(const void *a, const void *data), const void *data);
+// Return index for an item that returns 0 for given compare
+// function or -1 if none matches.
+int list_binary_find(list_t *list, int compare(const void *item, const void *data), const void *data, size_t size);
 #endif