intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 24 insertions, 0 deletions

diff --git a/library/cpp/yson_pull/detail/zigzag.h b/library/cpp/yson_pull/detail/zigzag.h
new file mode 100644
index 0000000000..98fcac0e9f
--- /dev/null
+++ b/library/cpp/yson_pull/detail/zigzag.h
@@ -0,0 +1,24 @@
+#pragma once
+
+#include "traits.h"
+
+namespace NYsonPull {
+    namespace NDetail {
+        namespace NZigZag {
+            //! Functions that provide coding of integers with property: 0 <= f(x) <= 2 * |x|
+
+            template <typename TSigned>
+            inline NTraits::to_unsigned<TSigned> encode(TSigned x) {
+                using TUnsigned = NTraits::to_unsigned<TSigned>;
+                constexpr auto rshift = sizeof(TSigned) * 8 - 1;
+                return (static_cast<TUnsigned>(x) << 1) ^ static_cast<TUnsigned>(x >> rshift);
+            }
+
+            template <typename TUnsigned>
+            inline NTraits::to_signed<TUnsigned> decode(TUnsigned x) {
+                using TSigned = NTraits::to_signed<TUnsigned>;
+                return static_cast<TSigned>(x >> 1) ^ -static_cast<TSigned>(x & 1);
+            }
+        }
+    }     // namespace NDetail
+}