intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 109 insertions, 0 deletions

diff --git a/library/cpp/yt/misc/guid.h b/library/cpp/yt/misc/guid.h
new file mode 100644
index 00000000000..ec4ba3526af
--- /dev/null
+++ b/library/cpp/yt/misc/guid.h
@@ -0,0 +1,109 @@
+#pragma once
+
+#include <util/generic/string.h>
+#include <util/generic/typetraits.h>
+
+#include <library/cpp/yt/exception/exception.h>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+//! TGuid is 16-byte value that might be interpreted as four little-endian 32-bit integers or two 64-bit little-endian integers.
+/*!
+ *    *-------------------------*-------------------------*
+ *    |       Parts64[0]        |       Parts64[1]        |
+ *    *------------*------------*------------*------------*
+ *    | Parts32[0] | Parts32[1] | Parts32[2] | Parts32[3] |
+ *    *------------*------------*------------*------------*
+ *    | 15..............................................0 |
+ *    *---------------------------------------------------*
+ *
+ *  Note, that bytes are kept in memory in reverse order.
+ *
+ *  Canonical text representation of guid consists of four base-16 numbers.
+ *  In text form, Parts32[3] comes first, and Parts32[0] comes last.
+ *
+ *  For example:
+ *
+ *    xxyyzzaa-0-1234-ff
+ *
+ *      xx is byte [0]
+ *      yy is byte [1]
+ *      zz is byte [2]
+ *      12 is byte [8]
+ *      34 is byte [9]
+ *      ff is byte [15]
+ */
+struct TGuid
+{
+    union
+    {
+        ui32 Parts32[4];
+        ui64 Parts64[2];
+        ui8 ReversedParts8[16];
+    };
+
+    //! Constructs a null (zero) guid.
+    constexpr TGuid();
+
+    //! Constructs guid from parts.
+    constexpr TGuid(ui32 part0, ui32 part1, ui32 part2, ui32 part3);
+
+    //! Constructs guid from parts.
+    constexpr TGuid(ui64 part0, ui64 part1);
+
+    //! Copies an existing guid.
+    TGuid(const TGuid& other) = default;
+
+    //! Checks if TGuid is zero.
+    bool IsEmpty() const;
+
+    //! Converts TGuid to bool, returns |false| iff TGuid is zero.
+    explicit operator bool() const;
+
+    //! Creates a new instance.
+    static TGuid Create();
+
+    //! Parses guid from TStringBuf, throws an exception if something went wrong.
+    static TGuid FromString(TStringBuf str);
+
+    //! Parses guid from TStringBuf, returns |true| if everything was ok.
+    static bool FromString(TStringBuf str, TGuid* guid);
+
+    //! Same as FromString, but expects exactly 32 hex digits without dashes.
+    static TGuid FromStringHex32(TStringBuf str);
+
+    //! Same as TryFromString, but expects exactly 32 hex digits without dashes.
+    static bool FromStringHex32(TStringBuf str, TGuid* guid);
+};
+
+bool operator == (TGuid lhs, TGuid rhs);
+bool operator != (TGuid lhs, TGuid rhs);
+bool operator <  (TGuid lhs, TGuid rhs);
+
+////////////////////////////////////////////////////////////////////////////////
+
+constexpr int MaxGuidStringSize = 4 * 8 + 3;
+char* WriteGuidToBuffer(char* ptr, TGuid value);
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
+
+////////////////////////////////////////////////////////////////////////////////
+
+Y_DECLARE_PODTYPE(NYT::TGuid);
+
+//! A hasher for TGuid.
+template <>
+struct THash<NYT::TGuid>
+{
+    size_t operator()(const NYT::TGuid& guid) const;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+#define GUID_INL_H_
+#include "guid-inl.h"
+#undef GUID_INL_H_