cpp-d1064d

[cross.git] / i686-linux-gnu-4.7 / usr / include / c++ / 4.7 / parallel / equally_split.h

diff --git a/i686-linux-gnu-4.7/usr/include/c++/4.7/parallel/equally_split.h b/i686-linux-gnu-4.7/usr/include/c++/4.7/parallel/equally_split.h
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+// -*- C++ -*-
+
+// Copyright (C) 2007, 2008, 2009, 2010, 2011 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/>.
+
+/** @file parallel/equally_split.h
+ *  This file is a GNU parallel extension to the Standard C++ Library.
+ */
+
+// Written by Johannes Singler.
+
+#ifndef _GLIBCXX_PARALLEL_EQUALLY_SPLIT_H
+#define _GLIBCXX_PARALLEL_EQUALLY_SPLIT_H 1
+
+namespace __gnu_parallel
+{
+  /** @brief function to split a sequence into parts of almost equal size.
+   *
+   *  The resulting sequence __s of length __num_threads+1 contains the
+   *  splitting positions when splitting the range [0,__n) into parts of
+   *  almost equal size (plus minus 1).  The first entry is 0, the last
+   *  one n. There may result empty parts.
+   *  @param __n Number of elements
+   *  @param __num_threads Number of parts
+   *  @param __s Splitters
+   *  @returns End of __splitter sequence, i.e. @c __s+__num_threads+1 */
+  template<typename _DifferenceType, typename _OutputIterator>
+    _OutputIterator
+    __equally_split(_DifferenceType __n, _ThreadIndex __num_threads,
+                   _OutputIterator __s)
+    {
+      _DifferenceType __chunk_length = __n / __num_threads;
+      _DifferenceType __num_longer_chunks = __n % __num_threads;
+      _DifferenceType __pos = 0;
+      for (_ThreadIndex __i = 0; __i < __num_threads; ++__i)
+       {
+         *__s++ = __pos;
+         __pos += ((__i < __num_longer_chunks)
+                   ? (__chunk_length + 1) : __chunk_length);
+       }
+      *__s++ = __n;
+      return __s;
+    }
+
+  /** @brief function to split a sequence into parts of almost equal size.
+   *
+   *  Returns the position of the splitting point between
+   *  thread number __thread_no (included) and
+   *  thread number __thread_no+1 (excluded).
+   *  @param __n Number of elements
+   *  @param __num_threads Number of parts
+   *  @param __thread_no Number of threads
+   *  @returns splitting point */
+  template<typename _DifferenceType>
+    _DifferenceType
+    __equally_split_point(_DifferenceType __n,
+                         _ThreadIndex __num_threads,
+                         _ThreadIndex __thread_no)
+    {
+      _DifferenceType __chunk_length = __n / __num_threads;
+      _DifferenceType __num_longer_chunks = __n % __num_threads;
+      if (__thread_no < __num_longer_chunks)
+       return __thread_no * (__chunk_length + 1);
+      else
+       return __num_longer_chunks * (__chunk_length + 1)
+          + (__thread_no - __num_longer_chunks) * __chunk_length;
+    }
+}
+
+#endif /* _GLIBCXX_PARALLEL_EQUALLY_SPLIT_H */