Diff: hash.h

Revision:

0:b47c2a7920c2

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hash.h	Fri Mar 16 16:34:18 2018 +0000
@@ -0,0 +1,438 @@
+///\file
+
+/******************************************************************************
+The MIT License(MIT)
+
+Embedded Template Library.
+https://github.com/ETLCPP/etl
+http://www.etlcpp.com
+
+Copyright(c) 2014 jwellbelove
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files(the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions :
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+******************************************************************************/
+
+#ifndef __ETL_HASH__
+#define __ETL_HASH__
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "platform.h"
+
+// The default hash calculation.
+#include "fnv_1.h"
+#include "type_traits.h"
+#include "static_assert.h"
+
+///\defgroup hash Standard hash calculations
+///\ingroup maths
+
+namespace etl
+{
+  namespace __private_hash__
+  {
+    //*************************************************************************
+    /// Hash to use when size_t is 16 bits.
+    /// T is always expected to be size_t.
+    //*************************************************************************
+    template <typename T>
+    typename enable_if<sizeof(T) == sizeof(uint16_t), size_t>::type
+    generic_hash(const uint8_t* begin, const uint8_t* end)
+    {
+      uint32_t h = fnv_1a_32(begin, end);
+
+      return static_cast<size_t>(h ^ (h >> 16));
+    }
+
+    //*************************************************************************
+    /// Hash to use when size_t is 32 bits.
+    /// T is always expected to be size_t.
+    //*************************************************************************
+    template <typename T>
+    typename enable_if<sizeof(T) == sizeof(uint32_t), size_t>::type
+    generic_hash(const uint8_t* begin, const uint8_t* end)
+    {
+      return fnv_1a_32(begin, end);
+    }
+
+    //*************************************************************************
+    /// Hash to use when size_t is 64 bits.
+    /// T is always expected to be size_t.
+    //*************************************************************************
+    template <typename T>
+    typename enable_if<sizeof(T) == sizeof(uint64_t), size_t>::type
+    generic_hash(const uint8_t* begin, const uint8_t* end)
+    {
+      return fnv_1a_64(begin, end);
+    }
+  }
+
+  //***************************************************************************
+  /// Generic declaration for etl::hash
+  ///\ingroup hash
+  //***************************************************************************
+  template <typename T> struct hash;
+
+  //***************************************************************************
+  /// Specialisation for bool.
+  ///\ingroup hash
+  //***************************************************************************
+  template <>
+  struct hash <bool>
+  {
+    STATIC_ASSERT(sizeof(size_t) >= sizeof(bool), "size_t smaller than type");
+
+    size_t operator ()(bool v) const
+    {
+      return static_cast<size_t>(v);
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for char.
+  ///\ingroup hash
+  //***************************************************************************
+  template <>
+  struct hash<char>
+  {
+    STATIC_ASSERT(sizeof(size_t) >= sizeof(char), "size_t smaller than type");
+
+    size_t operator ()(char v) const
+    {
+      return static_cast<size_t>(v);
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for signed char.
+  ///\ingroup hash
+  //***************************************************************************
+  template<> struct
+  hash<signed char>
+  {
+    STATIC_ASSERT(sizeof(size_t) >= sizeof(signed char), "size_t smaller than type");
+
+    size_t operator ()(signed char v) const
+    {
+      return static_cast<size_t>(v);
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for unsigned char.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<unsigned char>
+  {
+    STATIC_ASSERT(sizeof(size_t) >= sizeof(unsigned char), "size_t smaller than type");
+
+    size_t operator ()(unsigned char v) const
+    {
+      return static_cast<size_t>(v);
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for wchar_t.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<wchar_t>
+  {
+    STATIC_ASSERT(sizeof(size_t) >= sizeof(wchar_t), "size_t smaller than type");
+
+    size_t operator ()(wchar_t v) const
+    {
+      return static_cast<size_t>(v);
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for short.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<short>
+  {
+    STATIC_ASSERT(sizeof(size_t) >= sizeof(short), "size_t smaller than type");
+
+    size_t operator ()(short v) const
+    {
+      return static_cast<size_t>(v);
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for unsigned short.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<unsigned short>
+  {
+    STATIC_ASSERT(sizeof(size_t) >= sizeof(unsigned short), "size_t smaller than type");
+
+    size_t operator ()(unsigned short v) const
+    {
+      return static_cast<size_t>(v);
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for int.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<int>
+  {
+    STATIC_ASSERT(sizeof(size_t) >= sizeof(int), "size_t smaller than type");
+
+    size_t operator ()(int v) const
+    {
+      return static_cast<size_t>(v);
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for unsigned int.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<unsigned int>
+  {
+    STATIC_ASSERT(sizeof(size_t) >= sizeof(unsigned int), "size_t smaller than type");
+
+    size_t operator ()(unsigned int v) const
+    {
+      return static_cast<size_t>(v);
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for long.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<long>
+  {
+    size_t operator ()(long v) const
+    {
+      // If it's the same size as a size_t.
+      if (sizeof(size_t) >= sizeof(v))
+      {
+        return static_cast<size_t>(v);
+      }
+      else
+      {
+        uint8_t* p = reinterpret_cast<uint8_t*>(&v);
+        return __private_hash__::generic_hash<size_t>(p, p + sizeof(v));
+      }
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for long long.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<long long>
+  {
+    size_t operator ()(long long v) const
+    {
+      // If it's the same size as a size_t.
+      if (sizeof(size_t) >= sizeof(v))
+      {
+        return static_cast<size_t>(v);
+      }
+      else
+      {
+        uint8_t* p = reinterpret_cast<uint8_t*>(&v);
+        return __private_hash__::generic_hash<size_t>(p, p + sizeof(v));
+      }
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for unsigned long.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<unsigned long>
+  {
+    size_t  operator ()(unsigned long v) const
+    {
+      // If it's the same size as a size_t.
+      if (sizeof(size_t) >= sizeof(v))
+      {
+        return static_cast<size_t>(v);
+      }
+      else
+      {
+        uint8_t* p = reinterpret_cast<uint8_t*>(&v);
+        return __private_hash__::generic_hash<size_t>(p, p + sizeof(v));
+      }
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for unsigned long long.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<unsigned long long>
+  {
+    size_t  operator ()(unsigned long long v) const
+    {
+      // If it's the same size as a size_t.
+      if (sizeof(size_t) >= sizeof(v))
+      {
+        return static_cast<size_t>(v);
+      }
+      else
+      {
+        uint8_t* p = reinterpret_cast<uint8_t*>(&v);
+        return __private_hash__::generic_hash<size_t>(p, p + sizeof(v));
+      }
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for float.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<float>
+  {
+    size_t operator ()(float v) const
+    {
+      // If it's the same size as a size_t.
+      if (sizeof(size_t) == sizeof(v))
+      {
+        union
+        {
+          size_t s;
+          float  v;
+        } u;
+
+        u.v = v;
+
+        return u.s;
+      }
+      else
+      {
+        uint8_t* p = reinterpret_cast<uint8_t*>(&v);
+        return __private_hash__::generic_hash<size_t>(p, p + sizeof(v));
+      }
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for double.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<double>
+  {
+    size_t  operator ()(double v) const
+    {
+      // If it's the same size as a size_t.
+      if (sizeof(size_t) == sizeof(v))
+      {
+        union
+        {
+          size_t s;
+          double v;
+        } u;
+
+        u.v = v;
+        
+        return u.s;
+      }
+      else
+      {
+        uint8_t* p = reinterpret_cast<uint8_t*>(&v);
+        return __private_hash__::generic_hash<size_t>(p, p + sizeof(v));
+      }
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for long double.
+  ///\ingroup hash
+  //***************************************************************************
+  template<>
+  struct hash<long double>
+  {
+    size_t operator ()(long double v) const
+    {
+      // If it's the same size as a size_t.
+      if (sizeof(size_t) == sizeof(v))
+      {
+        union
+        {
+          size_t s;
+          long double v;
+        } u;
+
+        u.v = v;
+
+        return u.s;
+      }
+      else
+      {
+        uint8_t* p = reinterpret_cast<uint8_t*>(&v);
+        return __private_hash__::generic_hash<size_t>(p, p + sizeof(v));
+      }
+    }
+  };
+
+  //***************************************************************************
+  /// Specialisation for pointers.
+  ///\ingroup hash
+  //***************************************************************************
+  template <typename T>
+  struct hash<T*>
+  {
+    size_t operator ()(const T* v) const
+    {
+      // If it's the same size as a size_t.
+      if (sizeof(size_t) == sizeof(T*))
+      {
+        union
+        {
+          size_t s;
+          const T* v;
+        } u;
+
+        u.v = v;
+
+        return u.s;
+      }
+      else
+      {
+        uint8_t* p = reinterpret_cast<uint8_t*>(&v);
+        return __private_hash__::generic_hash<size_t>(p, p + sizeof(v));
+      }
+    }
+  };
+}
+
+#endif
+