added hash and byte array view

src/glow/common/array_view.hh

@@ -81,6 +81,14 @@ struct array_view
 
     constexpr bool empty() const { return _size == 0; }
 
+    array_view<std::byte const> as_bytes() const
+    {
+#ifndef GLOW_HAS_GLM
+        static_assert(std::is_trivially_copyable_v<T>, "cannot make byte view for non-trivial type");
+#endif
+        return array_view<std::byte const>{reinterpret_cast<std::byte const*>(_data), _size * sizeof(T)};
+    }
+
 private:
     T* _data = nullptr;
     size_t _size = 0;
@@ -96,6 +104,20 @@ auto make_array_view(Range&& r)
 namespace detail
 {
 template <class Range>
-constexpr bool can_make_array_view = convertible_to_array_view<Range, void>;
+constexpr bool can_make_array_view = convertible_to_array_view<Range, void const>;
+}
+
+template <class T>
+array_view<std::byte const> as_byte_view(T const& v)
+{
+    if constexpr (detail::can_make_array_view<T const&>)
+        return make_array_view(v).as_bytes();
+    else
+    {
+#ifndef GLOW_HAS_GLM
+        static_assert(std::is_trivially_copyable_v<T>, "type must be trivial");
+#endif
+        return array_view<T const>(&v, 1).as_bytes();
+    }
 }
 }

src/glow/common/hash.cc

+#include "hash.hh"
+
+#include <glow/detail/xxHash/xxh3.hh>
+
+size_t glow::hash_xxh3(array_view<const std::byte> data, size_t seed)
+{
+    //
+    return XXH3_64bits_withSeed(data.data(), data.size(), seed);
+}

src/glow/common/hash.hh

+#pragma once
+
+#include <cstddef>
+
+#include <glow/common/array_view.hh>
+
+namespace glow
+{
+// returns a hash of the data by executing https://github.com/Cyan4973/xxHash
+[[nodiscard]] size_t hash_xxh3(array_view<std::byte const> data, size_t seed);
+}

src/glow/detail/xxHash/xxhash.cc

+/*
+ * xxHash - Extremely Fast Hash algorithm
+ * Copyright (C) 2012-2020 Yann Collet
+ *
+ * BSD 2-Clause License (https://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *    * Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *    * Redistributions in binary form must reproduce the above
+ *      copyright notice, this list of conditions and the following disclaimer
+ *      in the documentation and/or other materials provided with the
+ *      distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * You can contact the author at:
+ *   - xxHash homepage: https://www.xxhash.com
+ *   - xxHash source repository: https://github.com/Cyan4973/xxHash
+ */
+
+
+/*
+ * xxhash.c instantiates functions defined in xxhash.h
+ */
+
+#define XXH_STATIC_LINKING_ONLY /* access advanced declarations */
+#define XXH_IMPLEMENTATION      /* access definitions */
+
+#include "xxhash.hh"