cpp-d1064d

[cross.git] / i686-linux-gnu-4.7 / usr / include / c++ / 4.7 / ext / pb_ds / detail / hash_fn / mask_based_range_hashing.hpp

diff --git a/i686-linux-gnu-4.7/usr/include/c++/4.7/ext/pb_ds/detail/hash_fn/mask_based_range_hashing.hpp b/i686-linux-gnu-4.7/usr/include/c++/4.7/ext/pb_ds/detail/hash_fn/mask_based_range_hashing.hpp
new file mode 100644 (file)
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+++ b/i686-linux-gnu-4.7/usr/include/c++/4.7/ext/pb_ds/detail/hash_fn/mask_based_range_hashing.hpp
@@ -0,0 +1,101 @@
+// -*- C++ -*-
+
+// Copyright (C) 2005, 2006, 2009 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software
+// Foundation; either version 3, or (at your option) any later
+// version.
+
+// This library is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
+
+// Permission to use, copy, modify, sell, and distribute this software
+// is hereby granted without fee, provided that the above copyright
+// notice appears in all copies, and that both that copyright notice
+// and this permission notice appear in supporting documentation. None
+// of the above authors, nor IBM Haifa Research Laboratories, make any
+// representation about the suitability of this software for any
+// purpose. It is provided "as is" without express or implied
+// warranty.
+
+/**
+ * @file mask_based_range_hashing.hpp
+ * Contains a range hashing policy base.
+ */
+
+#ifndef PB_DS_MASK_BASED_RANGE_HASHING_HPP
+#define PB_DS_MASK_BASED_RANGE_HASHING_HPP
+
+namespace __gnu_pbds
+{
+  namespace detail
+  {
+    /// Range hashing policy.
+    template<typename Size_Type>
+    class mask_based_range_hashing
+    {
+    protected:
+      typedef Size_Type        size_type;
+
+      void
+      swap(mask_based_range_hashing& other)
+      { std::swap(m_mask, other.m_mask); }
+
+      void
+      notify_resized(size_type size);
+
+      inline size_type
+      range_hash(size_type hash) const
+      { return size_type(hash & m_mask); }
+
+    private:
+      size_type                m_mask;
+      const static size_type   s_num_bits_in_size_type;
+      const static size_type   s_highest_bit_1;
+    };
+
+    template<typename Size_Type>
+    const typename mask_based_range_hashing<Size_Type>::size_type
+    mask_based_range_hashing<Size_Type>::s_num_bits_in_size_type =
+      sizeof(typename mask_based_range_hashing<Size_Type>::size_type) << 3;
+
+    template<typename Size_Type>
+    const typename mask_based_range_hashing<Size_Type>::size_type mask_based_range_hashing<Size_Type>::s_highest_bit_1 = static_cast<typename mask_based_range_hashing<Size_Type>::size_type>(1) << (s_num_bits_in_size_type - 1);
+
+ 
+    template<typename Size_Type>
+    void
+    mask_based_range_hashing<Size_Type>::
+    notify_resized(size_type size)
+    {
+      size_type i = 0;
+      while (size ^ s_highest_bit_1)
+       {
+         size <<= 1;
+         ++i;
+       }
+
+      m_mask = 1;
+      i += 2;
+      while (i++ < s_num_bits_in_size_type)
+        m_mask = (m_mask << 1) ^ 1;
+    }
+  } // namespace detail
+} // namespace __gnu_pbds
+
+#endif