1 files changed, 77 insertions, 0 deletions
diff --git a/Source/cmRange.h b/Source/cmRange.h
new file mode 100644
index 0000000..5a2f699
--- /dev/null
+++ b/Source/cmRange.h
@@ -0,0 +1,77 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#ifndef cmRange_h
+#define cmRange_h
+
+#include "cmConfigure.h" // IWYU pragma: keep
+
+#include "cm_kwiml.h"
+#include <algorithm>
+#include <iterator>
+
+template <typename const_iterator_>
+struct cmRange
+{
+  typedef const_iterator_ const_iterator;
+  typedef typename std::iterator_traits<const_iterator>::value_type value_type;
+  typedef typename std::iterator_traits<const_iterator>::difference_type
+    difference_type;
+  cmRange(const_iterator begin_, const_iterator end_)
+    : Begin(begin_)
+    , End(end_)
+  {
+  }
+  const_iterator begin() const { return Begin; }
+  const_iterator end() const { return End; }
+  bool empty() const { return std::distance(Begin, End) == 0; }
+  difference_type size() const { return std::distance(Begin, End); }
+
+  cmRange& advance(KWIML_INT_intptr_t amount) &
+  {
+    std::advance(this->Begin, amount);
+    return *this;
+  }
+  cmRange advance(KWIML_INT_intptr_t amount) &&
+  {
+    std::advance(this->Begin, amount);
+    return std::move(*this);
+  }
+
+  cmRange& retreat(KWIML_INT_intptr_t amount) &
+  {
+    std::advance(End, -amount);
+    return *this;
+  }
+
+  cmRange retreat(KWIML_INT_intptr_t amount) &&
+  {
+    std::advance(End, -amount);
+    return std::move(*this);
+  }
+
+private:
+  const_iterator Begin;
+  const_iterator End;
+};
+
+template <typename Iter1, typename Iter2>
+cmRange<Iter1> cmMakeRange(Iter1 begin, Iter2 end)
+{
+  return cmRange<Iter1>(begin, end);
+}
+
+template <typename Range>
+cmRange<typename Range::const_iterator> cmMakeRange(Range const& range)
+{
+  return cmRange<typename Range::const_iterator>(range.begin(), range.end());
+}
+
+template <typename Range>
+cmRange<typename Range::const_reverse_iterator> cmReverseRange(
+  Range const& range)
+{
+  return cmRange<typename Range::const_reverse_iterator>(range.rbegin(),
+                                                         range.rend());
+}
+
+#endif