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Update from Daryle

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[SVN r14187]
This commit is contained in:
Björn Karlsson
2002-06-19 20:11:17 +00:00
parent 41620a14f9
commit c56e4674f8
2 changed files with 54 additions and 3 deletions
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5
doc/static_log2.html
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@ -107,11 +107,12 @@ at compile-time) available.</p>
<h2><a name="credits">Credits</a></h2>
<p>The author of the Boost binary logarithm class template is <a
href="../../../people/daryle_walker.html">Daryle Walker</a>.</p>
href="../../../people/daryle_walker.html">Daryle Walker</a>. Giovanni Bajo
added support for compilers without partial template specialization.</p>
<hr>
<p>Revised October 1, 2001</p>
<p>Revised May 14, 2002</p>
<p>&copy; Copyright Daryle Walker 2001. Permission to copy, use,
modify, sell and distribute this document is granted provided this

52
include/boost/integer/static_log2.hpp
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@ -12,9 +12,13 @@
#include <boost/integer_fwd.hpp> // self include
#include <boost/config.hpp> // for BOOST_STATIC_CONSTANT
#include <boost/config.hpp> // for BOOST_STATIC_CONSTANT, etc.
#include <boost/limits.hpp> // for std::numeric_limits
#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
#include <boost/pending/ct_if.hpp> // for boost::ct_if<>
#endif
namespace boost
{
@ -30,9 +34,22 @@ template < unsigned long Val, int Place = 0, int Index
= std::numeric_limits<unsigned long>::digits >
struct static_log2_helper_t;
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
template < unsigned long Val, int Place >
struct static_log2_helper_t< Val, Place, 1 >;
#else
template < int Place >
struct static_log2_helper_final_step;
template < unsigned long Val, int Place = 0, int Index
= std::numeric_limits<unsigned long>::digits >
struct static_log2_helper_nopts_t;
#endif
// Recursively build the logarithm by examining the upper bits
template < unsigned long Val, int Place, int Index >
struct static_log2_helper_t
@ -50,7 +67,11 @@ private:
: Place );
BOOST_STATIC_CONSTANT( int, new_index = Index - half_place );
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
typedef static_log2_helper_t<new_val, new_place, new_index> next_step_type;
#else
typedef static_log2_helper_nopts_t<new_val, new_place, new_index> next_step_type;
#endif
public:
BOOST_STATIC_CONSTANT( int, value = next_step_type::value );
@ -58,6 +79,8 @@ public:
}; // boost::detail::static_log2_helper_t
// Non-recursive case
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
template < unsigned long Val, int Place >
struct static_log2_helper_t< Val, Place, 1 >
{
@ -66,6 +89,33 @@ public:
}; // boost::detail::static_log2_helper_t
#else
template < int Place >
struct static_log2_helper_final_step
{
public:
BOOST_STATIC_CONSTANT( int, value = Place );
}; // boost::detail::static_log2_helper_final_step
template < unsigned long Val, int Place, int Index >
struct static_log2_helper_nopts_t
{
private:
typedef static_log2_helper_t<Val, Place, Index> recursive_step_type;
typedef static_log2_helper_final_step<Place> final_step_type;
typedef typename ct_if<( Index != 1 ), recursive_step_type,
final_step_type>::type next_step_type;
public:
BOOST_STATIC_CONSTANT( int, value = next_step_type::value );
}; // boost::detail::static_log2_helper_nopts_t
#endif
} // namespace detail