[Boost-commit] svn:boost r75477 - sandbox/variadic_templates/sandbox/stepper/boost/array_stepper

Subject: [Boost-commit] svn:boost r75477 - sandbox/variadic_templates/sandbox/stepper/boost/array_stepper
From: cppljevans_at_[hidden]
Date: 2011-11-13 09:34:04

Author: cppljevans
Date: 2011-11-13 09:34:03 EST (Sun, 13 Nov 2011)
New Revision: 75477
URL: http://svn.boost.org/trac/boost/changeset/75477

Log:
add missing file
Added:
   sandbox/variadic_templates/sandbox/stepper/boost/array_stepper/permutation.hpp   (contents, props changed)

Added: sandbox/variadic_templates/sandbox/stepper/boost/array_stepper/permutation.hpp
==============================================================================
--- (empty file)
+++ sandbox/variadic_templates/sandbox/stepper/boost/array_stepper/permutation.hpp	2011-11-13 09:34:03 EST (Sun, 13 Nov 2011)
@@ -0,0 +1,97 @@
+#ifndef BOOST_ARRAY_STEPPER_PERMUTAION_HPP_INCLUDED
+#define BOOST_ARRAY_STEPPER_PERMUTAION_HPP_INCLUDED
+#include <boost/array_stepper/mk_iota.hpp>
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+#include <algorithm>
+#endif
+#include <boost/assert.hpp>
+
+namespace boost
+{
+namespace array_stepper
+{
+struct permutation
+: private std::vector<unsigned>
+{
+    typedef std::vector<unsigned> permute_maybe_t;
+    typedef permute_maybe_t::value_type value_type;
+    typedef permute_maybe_t::const_iterator const_iterator;
+    
+    permute_maybe_t const&impl()const
+    { 
+        return *this;
+    }
+    
+    unsigned operator[](unsigned i)const
+    { 
+        return impl()[i];
+    }
+    
+    typename permute_maybe_t::const_iterator begin()const
+    { 
+        return impl().begin();
+    }        
+    
+    typename permute_maybe_t::const_iterator end()const
+    { 
+        return impl().end();
+    }        
+    
+    static bool is_permutation(permute_maybe_t const& a_permute_maybe)
+    {
+      #ifdef __GXX_EXPERIMENTAL_CXX0X__
+        return 
+          std::is_permutation
+          ( a_permute_maybe.begin()
+          , a_permute_maybe.end()
+          , mk_iota(value_type(0),value_type(a_permute_maybe.size())).begin()
+          );
+      #else
+        std::vector<bool> is_found(a_permute_maybe.size(),false);
+        unsigned num_found=0;
+        unsigned const n=a_permute_maybe.size();
+        for(unsigned i=0; i<n; ++i)
+        {
+            value_type j=a_permute_maybe[i];
+            if(n<=j) return false;
+            if(is_found[j]) return false;
+            is_found[j]=true;
+            ++num_found;
+        }
+        return num_found==n;
+      #endif
+    }
+    
+    permutation(std::size_t s=0)
+    : permute_maybe_t(mk_iota(value_type(0),value_type(s)))
+    {}
+    
+    permutation(permute_maybe_t const& a_permute_maybe_v)
+    : permute_maybe_t(a_permute_maybe_v)
+    {
+        BOOST_ASSERT(is_permutation(a_permute_maybe_v));
+    }
+    
+    struct assert_is_permutation{};
+    
+    permutation( assert_is_permutation, permute_maybe_t const& a_permute_maybe_v)
+    : permute_maybe_t(a_permute_maybe_v)
+    {}
+
+    permutation permute( permute_maybe_t const& other)
+    {
+        BOOST_ASSERT(is_permutation(other));
+        unsigned const n=other.size();
+        permute_maybe_t const&me=impl();
+        BOOST_ASSERT(n==me.size());
+        permute_maybe_t permuted(n);
+        for(unsigned i=0; i<n; ++i) permuted[i]=me[other[i]];
+        assert_is_permutation is_perm;
+        return permutation( is_perm, permuted);
+    }    
+
+};
+
+}//exit array_stepper namespace
+}//exit boost namespace
+#endif