From 5c3bcde8f859b08275fa09f32800360ee541d5bd Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Mon, 17 Oct 2022 11:35:46 +0200
Subject: a

---
 compat/assert.hpp   | 16 ++++++++++++++++
 compat/defs.hpp     |  2 ++
 compat/int-hash.hpp | 30 ++++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+)
 create mode 100644 compat/int-hash.hpp

(limited to 'compat')

diff --git a/compat/assert.hpp b/compat/assert.hpp
index 860a9cde..04c5acbe 100644
--- a/compat/assert.hpp
+++ b/compat/assert.hpp
@@ -59,3 +59,19 @@ constexpr inline void abort(const char (&fmt)[N], Xs... xs) noexcept
 #define ERR(...)        ::floormat::detail::emit_debug("error: ", __VA_ARGS__)
 #define MESSAGE(...)    ::floormat::detail::emit_debug("", __VA_ARGS__)
 #define DEBUG(...)      ::floormat::detail::emit_debug("", __VA_ARGS__)
+
+namespace floormat {
+
+template<bool>
+struct static_warning_ final {
+    [[deprecated]] constexpr static_warning_() = default;
+};
+
+template<>
+struct static_warning_<true> final {
+    constexpr static_warning_() = default;
+};
+
+#define static_warning(...) do { (void)static_warning_<(__VA_ARGS__)>{};  } while(false)
+
+} // namespace floormat
diff --git a/compat/defs.hpp b/compat/defs.hpp
index 818e004b..632bafe5 100644
--- a/compat/defs.hpp
+++ b/compat/defs.hpp
@@ -15,3 +15,5 @@
 #define DECLARE_DELETED_COPY_ASSIGNMENT(type)               \
     type(const type&) = delete;                             \
     type& operator=(const type&) = delete
+
+
diff --git a/compat/int-hash.hpp b/compat/int-hash.hpp
new file mode 100644
index 00000000..43b92605
--- /dev/null
+++ b/compat/int-hash.hpp
@@ -0,0 +1,30 @@
+#pragma once
+#include <cstddef>
+
+namespace floormat {
+
+constexpr inline std::size_t int_hash(std::size_t x) noexcept
+{
+    if constexpr(sizeof(std::size_t) == 4)
+    {
+        // by Chris Wellons <https://nullprogram.com/blog/2018/07/31/>
+        x ^= x >> 15;
+        x *= 0x2c1b3c6dU;
+        x ^= x >> 12;
+        x *= 0x297a2d39U;
+        x ^= x >> 15;
+    }
+    else if constexpr(sizeof(std::size_t) == 8)
+    {
+        // splitmix64 by George Marsaglia
+        x ^= x >> 30;
+        x *= 0xbf58476d1ce4e5b9U;
+        x ^= x >> 27;
+        x *= 0x94d049bb133111ebU;
+        x ^= x >> 31;
+    }
+
+    return x;
+}
+
+} // namespace floormat
-- 
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