XPath round() is now fully compliant

git-svn-id: http://pugixml.googlecode.com/svn/trunk@461 99668b35-9821-0410-8761-19e4c4f06640

1 files changed, 12 insertions, 7 deletions

diff --git a/src/pugixpath.cpp b/src/pugixpath.cpp
index 9562ca1..d20baad 100644
--- a/src/pugixpath.cpp
+++ b/src/pugixpath.cpp
@@ -436,9 +436,15 @@ namespace
 	#endif

 	}

 	

-	double ieee754_round(double value)

+	double round_nearest(double value)

 	{

-		return is_nan(value) ? value : floor(value + 0.5);

+		return floor(value + 0.5);

+	}

+

+	double round_nearest_nzero(double value)

+	{

+		// same as round_nearest, but returns -0 for [-0.5, -0]

+		return (value >= -0.5 && value <= 0) ? ceil(value) : floor(value + 0.5);

 	}

 	

 	const char_t* local_name(const char_t* name)

@@ -2104,8 +2110,7 @@ namespace pugi
 			}

 

 			case ast_func_round:

-				// correct except for negative zero (it returns positive zero instead of negative)

-				return ieee754_round(m_left->eval_number(c));

+				return round_nearest_nzero(m_left->eval_number(c));

 			

 			default:

 			{

@@ -2232,7 +2237,7 @@ namespace pugi
 			case ast_func_substring_2:

 			{

 				string_t s = m_left->eval_string(c);

-				double first = ieee754_round(m_right->eval_number(c));

+				double first = round_nearest(m_right->eval_number(c));

 				

 				if (is_nan(first)) return string_t(); // NaN

 				else if (first >= s.length() + 1) return string_t();

@@ -2245,8 +2250,8 @@ namespace pugi
 			case ast_func_substring_3:

 			{

 				string_t s = m_left->eval_string(c);

-				double first = ieee754_round(m_right->eval_number(c));

-				double last = first + ieee754_round(m_third->eval_number(c));

+				double first = round_nearest(m_right->eval_number(c));

+				double last = first + round_nearest(m_third->eval_number(c));

 				

 				if (is_nan(first) || is_nan(last)) return string_t();

 				else if (first >= s.length() + 1) return string_t();