[Boost-commit] svn:boost r64197 - sandbox/SOC/2010/bits_and_ints/boost/integer

Subject: [Boost-commit] svn:boost r64197 - sandbox/SOC/2010/bits_and_ints/boost/integer
From: muriloufg_at_[hidden]
Date: 2010-07-20 09:53:51

Author: murilov
Date: 2010-07-20 09:53:50 EDT (Tue, 20 Jul 2010)
New Revision: 64197
URL: http://svn.boost.org/trac/boost/changeset/64197

Log:
Added count_leading_zeros() verification:
If value is 0, now it returns the size in bits of value type
Added policies on ilog2() function:
- Now if value is 0, an indeterminate_result_error is raised and the user can handle this error according the policy utilized.
Text files modified: 
   sandbox/SOC/2010/bits_and_ints/boost/integer/count_leading_zeros.hpp |    54 ++++++++++++++++----------------------- 
   sandbox/SOC/2010/bits_and_ints/boost/integer/ilog2.hpp               |    28 +++++++++++++++++--                     
   2 files changed, 46 insertions(+), 36 deletions(-)

Modified: sandbox/SOC/2010/bits_and_ints/boost/integer/count_leading_zeros.hpp
==============================================================================
--- sandbox/SOC/2010/bits_and_ints/boost/integer/count_leading_zeros.hpp	(original)
+++ sandbox/SOC/2010/bits_and_ints/boost/integer/count_leading_zeros.hpp	2010-07-20 09:53:50 EDT (Tue, 20 Jul 2010)
@@ -30,53 +30,43 @@
 #ifdef __GNUC__
 
 template <typename T>
-inline int unchecked_count_leading_zeros(T value)
-{
-	return __builtin_clz(value) - (32 - (sizeof(T) << 3));
-}
-	
-template <typename T>
 inline int count_leading_zeros(T value)
 {
-	return (value != 0) ?
-		__builtin_clz(value) - (32 - (sizeof(T) << 3)) : -1;
+	if (value == 0) {
+		return sizeof(T) << 3;
+	}
+	
+	return __builtin_clz(value) - (32 - (sizeof(T) << 3));
 }
 
-inline int unchecked_count_leading_zeros(unsigned int value)
-{
-	return (value != 0) ? 
-		__builtin_clz(value) : -1;
-}
-	
 inline int count_leading_zeros(unsigned int value)
 {
-	return __builtin_clz(value);
-}
+	if (value == 0) {
+		return sizeof(unsigned int) << 3;
+	}
         
-inline int unchecked_count_leading_zeros(unsigned long int value)
-{
-	return __builtin_clzl(value);
+	return __builtin_clz(value);
 }
-	
+
 inline int count_leading_zeros(unsigned long int value)
 {
-	return (value != 0) ? 
-		__builtin_clzl(value) : -1;
+	if (value == 0) {
+		return sizeof(unsigned long int) << 3;
+	}
+	
+	return __builtin_clzl(value);
 }
 
 #ifndef BOOST_HAS_NO_INT64_T
-inline int unchecked_count_leading_zeros(unsigned long long int value)
-{
-	return __builtin_clzll(value);
-}
-	
-	
 inline int count_leading_zeros(unsigned long long int value)
-{
-	return (value != 0) ?
-		__builtin_clzll(value) : -1; 
+{	
+	if (value == 0) {
+		return sizeof(unsigned long long int) << 3;
+	}
+	
+	return __builtin_clzll(value);
 }
-#endif
+#endif	
 
 #else
 

Modified: sandbox/SOC/2010/bits_and_ints/boost/integer/ilog2.hpp
==============================================================================
--- sandbox/SOC/2010/bits_and_ints/boost/integer/ilog2.hpp	(original)
+++ sandbox/SOC/2010/bits_and_ints/boost/integer/ilog2.hpp	2010-07-20 09:53:50 EDT (Tue, 20 Jul 2010)
@@ -13,6 +13,8 @@
 #include <boost/static_assert.hpp>
 #include <boost/utility/enable_if.hpp>
 #include <boost/type_traits/is_unsigned.hpp>
+#include <boost/math/policies/policy.hpp>
+#include <boost/math/policies/error_handling.hpp>
 #include <boost/integer/count_leading_zeros.hpp>
 
 namespace boost {
@@ -21,15 +23,33 @@
  *	This function returns the integer value of 
  *		logarithm in base 2 of an unsigned integral `value`
  *
- *	If `value` is equal to 0, the value returned is undefined
+ *	If `value` is equal to 0, the value returned is -1 and
+ *		one error is raised according with the policy used.
+ *
+ *	See the math::policies documentation for more details.
  *
  *	`value` must be unsigned.
  */
+template <typename T, typename Policy>
+inline typename enable_if<is_unsigned<T>, int>::type
+ilog2(T value, const Policy& pol)
+{
+	if (value == 0) {
+		return math::policies::raise_indeterminate_result_error(
+			"boost::ilog2(%1%)",
+			"ilog2 is indeterminate for value 0, retunrning -1",
+			0, -1, pol
+		);
+	}
+	
+	return (sizeof(T) << 3) - count_leading_zeros(value) - 1;
+}
+
 template <typename T>
-inline typename enable_if<is_unsigned<T>, T>::type
+inline typename enable_if<is_unsigned<T>, int>::type
 ilog2(T value)
-{	
-	return (sizeof(T) * 8) - count_leading_zeros(value) - 1;
+{
+	return ilog2(value, math::policies::policy<>());
 }
         
 }