1 files changed, 48 insertions, 0 deletions
diff --git a/Tools/c-analyzer/c_common/iterutil.py b/Tools/c-analyzer/c_common/iterutil.py
new file mode 100644
index 00000000000..6ded105304e
--- /dev/null
+++ b/Tools/c-analyzer/c_common/iterutil.py
@@ -0,0 +1,48 @@
+
+_NOT_SET = object()
+
+
+def peek_and_iter(items):
+    if not items:
+        return None, None
+    items = iter(items)
+    try:
+        peeked = next(items)
+    except StopIteration:
+        return None, None
+    def chain():
+        yield peeked
+        yield from items
+    return chain(), peeked
+
+
+def iter_many(items, onempty=None):
+    if not items:
+        if onempty is None:
+            return
+        if not callable(onempty):
+            raise onEmpty
+        items = onempty(items)
+        yield from iter_many(items, onempty=None)
+        return
+    items = iter(items)
+    try:
+        first = next(items)
+    except StopIteration:
+        if onempty is None:
+            return
+        if not callable(onempty):
+            raise onEmpty
+        items = onempty(items)
+        yield from iter_many(items, onempty=None)
+    else:
+        try:
+            second = next(items)
+        except StopIteration:
+            yield first, False
+            return
+        else:
+            yield first, True
+            yield second, True
+        for item in items:
+            yield item, True