locale_facets.tcc (num_get<>::_M_extract_int): Evaluate *__beg the exact strict…

locale_facets.tcc (num_get<>::_M_extract_int): Evaluate *__beg the exact strict minimum number of times...

2004-11-02  Paolo Carlini  <pcarlini@suse.de>

	* include/bits/locale_facets.tcc (num_get<>::_M_extract_int):
	Evaluate *__beg the exact strict minimum number of times; likewise
	for __beg != __end; slightly simplify main parsing loop.

From-SVN: r90012

libstdc++-v3/ChangeLog

+2004-11-02  Paolo Carlini  <pcarlini@suse.de>
+
+	* include/bits/locale_facets.tcc (num_get<>::_M_extract_int):
+	Evaluate *__beg the exact strict minimum number of times; likewise
+	for __beg != __end; slightly simplify main parsing loop.
+
 2004-11-02  Benjamin Kosnik  <bkoz@redhat.com>
   	    Lothar Werzinger  <lothar@xcerla.com>
 	

libstdc++-v3/include/bits/locale_facets.tcc

@@ -301,10 +301,8 @@ namespace std
 	    }
 	}
 
-      // True if a mantissa is found.
-      bool __found_mantissa = false;
-
       // Next, look for leading zeros.
+      bool __found_mantissa = false;
       while (!__testeof)
 	{
 	  if (__lc->_M_use_grouping && __c == __lc->_M_thousands_sep
@@ -452,6 +450,7 @@ namespace std
 	const locale& __loc = __io._M_getloc();
 	const __cache_type* __lc = __uc(__loc);
 	const _CharT* __lit = __lc->_M_atoms_in;
+	char_type __c = char_type();
 
 	// NB: Iff __basefield == 0, __base can change based on contents.
 	const ios_base::fmtflags __basefield = __io.flags()
@@ -459,37 +458,39 @@ namespace std
 	const bool __oct = __basefield == ios_base::oct;
 	int __base = __oct ? 8 : (__basefield == ios_base::hex ? 16 : 10);
 
-	// True if numeric digits are found.
-	bool __found_num = false;
+	// True if __beg becomes equal to __end.
+	bool __testeof = __beg == __end;
 
 	// First check for sign.
 	bool __negative = false;
-	if (__beg != __end)
+	if (!__testeof)
 	  {
-	    const char_type __c = *__beg;
+	    __c = *__beg;
 	    if (numeric_limits<_ValueT>::is_signed)
 	      __negative = __c == __lit[__num_base::_S_iminus];
 	    if ((__negative || __c == __lit[__num_base::_S_iplus])
 		&& !(__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
 		&& !(__c == __lc->_M_decimal_point))
-	      ++__beg;
+	      {
+		if (++__beg != __end)
+		  __c = *__beg;
+		else
+		  __testeof = true;
+	      }
 	  }
 
 	// Next, look for leading zeros and check required digits
 	// for base formats.
-	while (__beg != __end)
+	bool __found_zero = false;
+	while (!__testeof)
 	  {
-	    const char_type __c = *__beg;
 	    if (__lc->_M_use_grouping && __c == __lc->_M_thousands_sep
 		|| __c == __lc->_M_decimal_point)
 	      break;
 	    else if (__c == __lit[__num_base::_S_izero] 
-		     && (!__found_num || __base == 10))
-	      {
-		__found_num = true;
-		++__beg;
-	      }
-	    else if (__found_num)
+		     && (!__found_zero || __base == 10))
+	      __found_zero = true;
+	    else if (__found_zero)
 	      {
 		if (__c == __lit[__num_base::_S_ix] 
 		    || __c == __lit[__num_base::_S_iX])
@@ -497,17 +498,28 @@ namespace std
 		    if (__basefield == 0)
 		      __base = 16;
 		    if (__base == 16)
-		      {
-			__found_num = false;
-			++__beg;
-		      }
+		      __found_zero = false;
+		    else
+		      break;
 		  }
-		else if (__basefield == 0)
+		else
+		  {
+		    if (__basefield == 0)
 		      __base = 8;
 		    break;
 		  }
+	      }
 	    else
 	      break;
+
+	    if (++__beg != __end)
+	      {
+		__c = *__beg;
+		if (!__found_zero)
+		  break;
+	      }
+	    else
+	      __testeof = true;
 	  }
 	
 	// At this point, base is determined. If not hex, only allow
@@ -522,15 +534,15 @@ namespace std
 	int __sep_pos = 0;
 	bool __overflow = false;
 	_ValueT __result = 0;
+	const char_type* __q;
 	const char_type* __lit_zero = __lit + __num_base::_S_izero;
 	if (__negative)
 	  {
 	    const _ValueT __min = numeric_limits<_ValueT>::min() / __base;
-	    for (; __beg != __end; ++__beg)
+	    while (!__testeof)
 	      {
 		// According to 22.2.2.1.2, p8-9, first look for thousands_sep
 		// and decimal_point.
-		const char_type __c = *__beg;
 		if (__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
 		  {
 		    // NB: Thousands separator at the beginning of a string
@@ -548,11 +560,7 @@ namespace std
 		  }
 		else if (__c == __lc->_M_decimal_point)
 		  break;
-		else
-		  {
-		    const char_type* __q = __traits_type::find(__lit_zero, 
-							       __len, __c);
-		    if (__q)
+		else if ((__q = __traits_type::find(__lit_zero, __len, __c)))
 		  {
 		    int __digit = __q - __lit_zero;
 		    if (__digit > 15)
@@ -566,21 +574,23 @@ namespace std
 			__overflow |= __new_result > __result;
 			__result = __new_result;
 			++__sep_pos;
-			    __found_num = true;
 		      }
 		  }
 		else
 		  // Not a valid input item.
 		  break;
-		  }
+
+		if (++__beg != __end)
+		  __c = *__beg;
+		else
+		  __testeof = true;
 	      }
 	  }
 	else
 	  {
 	    const _ValueT __max = numeric_limits<_ValueT>::max() / __base;
-	    for (; __beg != __end; ++__beg)
+	    while (!__testeof)
 	      {
-		const char_type __c = *__beg;
 		if (__lc->_M_use_grouping && __c == __lc->_M_thousands_sep)
 		  {
 		    if (__sep_pos)
@@ -596,11 +606,7 @@ namespace std
 		  }
 		else if (__c == __lc->_M_decimal_point)
 		  break;
-		else
-		  {
-		    const char_type* __q = __traits_type::find(__lit_zero,
-							       __len, __c);    
-		    if (__q)
+		else if ((__q = __traits_type::find(__lit_zero, __len, __c)))
 		  {
 		    int __digit = __q - __lit_zero;
 		    if (__digit > 15)
@@ -614,12 +620,15 @@ namespace std
 			__overflow |= __new_result < __result;
 			__result = __new_result;
 			++__sep_pos;
-			    __found_num = true;
 		      }
 		  }
 		else
 		  break;
-		  }
+
+		if (++__beg != __end)
+		  __c = *__beg;
+		else
+		  __testeof = true;
 	      }
 	  }
 
@@ -637,12 +646,12 @@ namespace std
 	  }
 
 	if (!(__err & ios_base::failbit) && !__overflow
-	    && __found_num)
+	    && (__sep_pos || __found_zero || __found_grouping.size()))
 	  __v = __result;
 	else
 	  __err |= ios_base::failbit;
 
-	if (__beg == __end)
+	if (__testeof)
 	  __err |= ios_base::eofbit;
 	return __beg;
       }