From 66b0fb8c4b4d1d7d97bd90a22a613b00b7d2d0a8 Mon Sep 17 00:00:00 2001
From: Werner Lemberg <wl@gnu.org>
Date: Sat, 9 Aug 2014 20:40:59 +0200
Subject: [PATCH] Add functions to iterate over number sets.

---
 lib/numberset.c | 32 ++++++++++++++++++++++++++++++++
 lib/numberset.h | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/lib/numberset.c b/lib/numberset.c
index d55246f..786c2d2 100644
--- a/lib/numberset.c
+++ b/lib/numberset.c
@@ -343,4 +343,36 @@ number_set_is_element(number_range* number_set,
   return 0;
 }
 
+
+int
+number_set_get_first(number_set_iter* iter_p)
+{
+  if (!iter_p || !iter_p->range)
+    return 0;
+
+  iter_p->val = iter_p->range->start;
+
+  return iter_p->val;
+}
+
+
+int
+number_set_get_next(number_set_iter* iter_p)
+{
+  if (!iter_p || !iter_p->range)
+    return 0;
+
+  iter_p->val++;
+
+  if (iter_p->val > iter_p->range->end)
+  {
+    iter_p->range = iter_p->range->next;
+
+    if (iter_p->range)
+      iter_p->val = iter_p->range->start;
+  }
+
+  return iter_p->val;
+}
+
 /* end of numberset.c */
diff --git a/lib/numberset.h b/lib/numberset.h
index 96fd7da..445961b 100644
--- a/lib/numberset.h
+++ b/lib/numberset.h
@@ -132,6 +132,38 @@ int
 number_set_is_element(number_range* number_set,
                       int number);
 
+
+/*
+ * A structure used to iterate over a number set.
+ */
+
+typedef struct number_set_iter_
+{
+  number_range* range;
+  int val;
+} number_set_iter;
+
+
+/*
+ * Get first element of a number set.  `iter_p' must be initialized with the
+ * `number_range' structure to iterate over.  After the call, `iter_p' is
+ * ready to be used in a call to `number_set_get_next'.
+ */
+
+int
+number_set_get_first(number_set_iter* iter_p);
+
+
+/*
+ * Get next element of a number set, using `iter_p' from a previous call to
+ * `number_set_get_first' or `number_set_get_next'.  If `iter_p->range' is
+ * NULL after the call, there is no next element, and the return value is
+ * undefined.
+ */
+
+int
+number_set_get_next(number_set_iter* iter_p);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
-- 
2.11.4.GIT