sdk: build libsupc++ from libstdc++ source

git-svn-id: svn://kolibrios.org@5134 a494cfbc-eb01-0410-851d-a64ba20cac60

contrib/sdk/sources/libstdc++-v3/include/parallel/search.h

@@ -0,0 +1,172 @@
+// -*- C++ -*-
+
+// Copyright (C) 2007-2013 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/search.h
+ *  @brief Parallel implementation base for std::search() and
+ *  std::search_n().
+ *  This file is a GNU parallel extension to the Standard C++ Library.
+ */
+
+// Written by Felix Putze.
+
+#ifndef _GLIBCXX_PARALLEL_SEARCH_H
+#define _GLIBCXX_PARALLEL_SEARCH_H 1
+
+#include <bits/stl_algobase.h>
+
+#include <parallel/parallel.h>
+#include <parallel/equally_split.h>
+
+namespace __gnu_parallel
+{
+  /**
+   *  @brief Precalculate __advances for Knuth-Morris-Pratt algorithm.
+   *  @param __elements Begin iterator of sequence to search for.
+   *  @param __length Length of sequence to search for.
+   *  @param __off Returned __offsets. 
+   */
+  template<typename _RAIter, typename _DifferenceTp>
+    void
+    __calc_borders(_RAIter __elements, _DifferenceTp __length, 
+		   _DifferenceTp* __off)
+    {
+      typedef _DifferenceTp _DifferenceType;
+
+      __off[0] = -1;
+      if (__length > 1)
+	__off[1] = 0;
+      _DifferenceType __k = 0;
+      for (_DifferenceType __j = 2; __j <= __length; __j++)
+	{
+          while ((__k >= 0) && !(__elements[__k] == __elements[__j-1]))
+            __k = __off[__k];
+          __off[__j] = ++__k;
+	}
+    }
+
+  // Generic parallel find algorithm (requires random access iterator).
+
+  /** @brief Parallel std::search.
+   *  @param __begin1 Begin iterator of first sequence.
+   *  @param __end1 End iterator of first sequence.
+   *  @param __begin2 Begin iterator of second sequence.
+   *  @param __end2 End iterator of second sequence.
+   *  @param __pred Find predicate.
+   *  @return Place of finding in first sequences. */
+  template<typename __RAIter1,
+           typename __RAIter2,
+           typename _Pred>
+    __RAIter1
+    __search_template(__RAIter1 __begin1, __RAIter1 __end1,
+		      __RAIter2 __begin2, __RAIter2 __end2,
+		      _Pred __pred)
+    {
+      typedef std::iterator_traits<__RAIter1> _TraitsType;
+      typedef typename _TraitsType::difference_type _DifferenceType;
+
+      _GLIBCXX_CALL((__end1 - __begin1) + (__end2 - __begin2));
+
+      _DifferenceType __pattern_length = __end2 - __begin2;
+
+      // Pattern too short.
+      if(__pattern_length <= 0)
+	return __end1;
+
+      // Last point to start search.
+      _DifferenceType __input_length = (__end1 - __begin1) - __pattern_length;
+
+      // Where is first occurrence of pattern? defaults to end.
+      _DifferenceType __result = (__end1 - __begin1);
+      _DifferenceType *__splitters;
+
+      // Pattern too long.
+      if (__input_length < 0)
+	return __end1;
+
+      omp_lock_t __result_lock;
+      omp_init_lock(&__result_lock);
+
+      _ThreadIndex __num_threads = std::max<_DifferenceType>
+	(1, std::min<_DifferenceType>(__input_length,
+				      __get_max_threads()));
+
+      _DifferenceType __advances[__pattern_length];
+      __calc_borders(__begin2, __pattern_length, __advances);
+
+#     pragma omp parallel num_threads(__num_threads)
+      {
+#       pragma omp single
+	{
+	  __num_threads = omp_get_num_threads();
+	  __splitters = new _DifferenceType[__num_threads + 1];
+	  __equally_split(__input_length, __num_threads, __splitters);
+	}
+
+	_ThreadIndex __iam = omp_get_thread_num();
+
+	_DifferenceType __start = __splitters[__iam],
+	                 __stop = __splitters[__iam + 1];
+
+	_DifferenceType __pos_in_pattern = 0;
+	bool __found_pattern = false;
+
+	while (__start <= __stop && !__found_pattern)
+	  {
+	    // Get new value of result.
+#pragma omp flush(__result)
+	    // No chance for this thread to find first occurrence.
+	    if (__result < __start)
+	      break;
+	    while (__pred(__begin1[__start + __pos_in_pattern],
+			  __begin2[__pos_in_pattern]))
+	      {
+		++__pos_in_pattern;
+		if (__pos_in_pattern == __pattern_length)
+		  {
+		    // Found new candidate for result.
+		    omp_set_lock(&__result_lock);
+		    __result = std::min(__result, __start);
+		    omp_unset_lock(&__result_lock);
+
+		    __found_pattern = true;
+		    break;
+		  }
+	      }
+	    // Make safe jump.
+	    __start += (__pos_in_pattern - __advances[__pos_in_pattern]);
+	    __pos_in_pattern = (__advances[__pos_in_pattern] < 0
+				? 0 : __advances[__pos_in_pattern]);
+	  }
+      } //parallel
+
+      omp_destroy_lock(&__result_lock);
+
+      delete[] __splitters;
+      
+      // Return iterator on found element.
+      return (__begin1 + __result);
+    }
+} // end namespace
+
+#endif /* _GLIBCXX_PARALLEL_SEARCH_H */