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Boost-Commit : |
Subject: [Boost-commit] svn:boost r85512 - trunk/boost
From: antoshkka_at_[hidden]
Date: 2013-08-29 07:41:28
Author: apolukhin
Date: 2013-08-29 07:41:28 EDT (Thu, 29 Aug 2013)
New Revision: 85512
URL: http://svn.boost.org/trac/boost/changeset/85512
Log:
lexical_cast.hpp improvements: better overflow detections for float conversions, more `const` modifiers (refs #9046)
Text files modified:
trunk/boost/lexical_cast.hpp | 139 ++++++++++++++++-----------------------
1 files changed, 57 insertions(+), 82 deletions(-)
Modified: trunk/boost/lexical_cast.hpp
==============================================================================
--- trunk/boost/lexical_cast.hpp Thu Aug 29 07:30:58 2013 (r85511)
+++ trunk/boost/lexical_cast.hpp 2013-08-29 07:41:28 EDT (Thu, 29 Aug 2013) (r85512)
@@ -891,14 +891,11 @@
const CharT plus = lcast_char_constants<CharT>::plus;
const int inifinity_size = 8;
- bool has_minus = false;
/* Parsing +/- */
- if( *begin == minus)
- {
+ bool const has_minus = (*begin == minus);
+ if (has_minus || *begin == plus) {
++ begin;
- has_minus = true;
}
- else if( *begin == plus ) ++begin;
if( end-begin < 3 ) return false;
if( lc_iequal(begin, lc_nan, lc_NAN, 3) )
@@ -1075,6 +1072,25 @@
template<class Traits, class T, class CharT>
inline bool lcast_ret_float(T& value, const CharT* begin, const CharT* end)
{
+ value = static_cast<T>(0);
+ if (begin == end) return false;
+ if (parse_inf_nan(begin, end, value)) return true;
+
+ CharT const czero = lcast_char_constants<CharT>::zero;
+ CharT const minus = lcast_char_constants<CharT>::minus;
+ CharT const plus = lcast_char_constants<CharT>::plus;
+ CharT const capital_e = lcast_char_constants<CharT>::capital_e;
+ CharT const lowercase_e = lcast_char_constants<CharT>::lowercase_e;
+
+ typedef BOOST_DEDUCED_TYPENAME Traits::int_type int_type;
+ int_type const zero = Traits::to_int_type(czero);
+
+ /* Getting the plus/minus sign */
+ bool const has_minus = Traits::eq(*begin, minus);
+ if (has_minus || Traits::eq(*begin, plus)) {
+ ++ begin;
+ if (begin == end) return false;
+ }
#ifndef BOOST_LEXICAL_CAST_ASSUME_C_LOCALE
std::locale loc;
@@ -1094,43 +1110,17 @@
CharT const decimal_point = lcast_char_constants<CharT>::c_decimal_separator;
#endif
- CharT const czero = lcast_char_constants<CharT>::zero;
- CharT const minus = lcast_char_constants<CharT>::minus;
- CharT const plus = lcast_char_constants<CharT>::plus;
- CharT const capital_e = lcast_char_constants<CharT>::capital_e;
- CharT const lowercase_e = lcast_char_constants<CharT>::lowercase_e;
-
- value = static_cast<T>(0);
-
- if (parse_inf_nan(begin, end, value)) return true;
-
- typedef typename Traits::int_type int_type;
- typedef BOOST_DEDUCED_TYPENAME mantissa_holder_type<T>::type mantissa_type;
- typedef BOOST_DEDUCED_TYPENAME mantissa_holder_type<T>::wide_result_t wide_result_t;
- int_type const zero = Traits::to_int_type(czero);
- if (begin == end) return false;
-
- /* Getting the plus/minus sign */
- bool has_minus = false;
- if (Traits::eq(*begin, minus) ) {
- ++ begin;
- has_minus = true;
- if (begin == end) return false;
- } else if (Traits::eq(*begin, plus) ) {
- ++begin;
- if (begin == end) return false;
- }
-
bool found_decimal = false;
bool found_number_before_exp = false;
- int pow_of_10 = 0;
+ typedef int pow_of_10_t;
+ pow_of_10_t pow_of_10 = 0;
+
+ typedef BOOST_DEDUCED_TYPENAME mantissa_holder_type<T>::type mantissa_type;
mantissa_type mantissa=0;
bool is_mantissa_full = false;
-
char length_since_last_delim = 0;
- while ( begin != end )
- {
+ while (begin != end) {
if (found_decimal) {
/* We allow no thousand_separators after decimal point */
@@ -1157,15 +1147,14 @@
* occur, them we only increase multiplyer
*/
const mantissa_type tmp_sub_value = static_cast<mantissa_type>(*begin - zero);
- if( !(is_mantissa_full
- || ((std::numeric_limits<mantissa_type>::max)() - tmp_sub_value) / 10u < mantissa)
+ if( is_mantissa_full
+ || ((std::numeric_limits<mantissa_type>::max)() - tmp_sub_value) / 10u < mantissa
)
{
- mantissa = static_cast<mantissa_type>(mantissa * 10 + tmp_sub_value);
- } else
- {
is_mantissa_full = true;
++ pow_of_10;
+ } else {
+ mantissa = static_cast<mantissa_type>(mantissa * 10 + tmp_sub_value);
}
found_number_before_exp = true;
@@ -1188,12 +1177,12 @@
) return false;
#endif
- if(Traits::eq(*begin, decimal_point)) {
+ if (Traits::eq(*begin, decimal_point)) {
++ begin;
found_decimal = true;
if (!found_number_before_exp && begin==end) return false;
continue;
- }else {
+ } else {
if (!found_number_before_exp) return false;
break;
}
@@ -1245,48 +1234,44 @@
++ begin;
if ( begin == end ) return false;
- bool exp_has_minus = false;
- if(Traits::eq(*begin, minus)) {
- exp_has_minus = true;
+ bool const exp_has_minus = Traits::eq(*begin, minus);
+ if (exp_has_minus || Traits::eq(*begin, plus)) {
++ begin;
- if ( begin == end ) return false;
- } else if (Traits::eq(*begin, plus)) {
- ++ begin;
- if ( begin == end ) return false;
+ if (begin == end) return false;
}
- int exp_pow_of_10 = 0;
- while ( begin != end )
- {
- if ( *begin < czero
- || *begin >= czero + 10
- || exp_pow_of_10 * 10 < exp_pow_of_10) /* Overflows are checked lower more precisely*/
+ pow_of_10_t exp_pow_of_10 = 0;
+ while (begin != end) {
+ pow_of_10_t const sub_value = *begin - zero;
+
+ if ( *begin < czero || *begin >= czero + 10
+ || ((std::numeric_limits<pow_of_10_t>::max)() - sub_value) / 10 < exp_pow_of_10)
return false;
exp_pow_of_10 *= 10;
- exp_pow_of_10 += *begin - zero;
+ exp_pow_of_10 += sub_value;
++ begin;
};
- if ( exp_pow_of_10 ) {
- /* Overflows are checked lower */
- if ( exp_has_minus ) {
- pow_of_10 -= exp_pow_of_10;
- } else {
- pow_of_10 += exp_pow_of_10;
- }
+ if (exp_has_minus) {
+ if ((std::numeric_limits<pow_of_10_t>::min)() + exp_pow_of_10 > pow_of_10)
+ return false; // failed overflow check
+ pow_of_10 -= exp_pow_of_10;
+ } else {
+ if ((std::numeric_limits<pow_of_10_t>::max)() - exp_pow_of_10 < pow_of_10)
+ return false; // failed overflow check
+ pow_of_10 += exp_pow_of_10;
}
}
/* We need a more accurate algorithm... We can not use current algorithm
* with long doubles (and with doubles if sizeof(double)==sizeof(long double)).
*/
+ typedef BOOST_DEDUCED_TYPENAME mantissa_holder_type<T>::wide_result_t wide_result_t;
const wide_result_t result = std::pow(static_cast<wide_result_t>(10.0), pow_of_10) * mantissa;
value = static_cast<T>( has_minus ? (boost::math::changesign)(result) : result);
- if ( (boost::math::isinf)(value) || (boost::math::isnan)(value) ) return false;
-
- return true;
+ return !((boost::math::isinf)(value) || (boost::math::isnan)(value));
}
// Unsilence buggy MS warnings like C4244: '+=' : conversion from 'int' to 'unsigned short', possible loss of data
#if defined(_MSC_VER) && (_MSC_VER == 1400)
@@ -1805,15 +1790,10 @@
if (start == finish) return false;
CharT const minus = lcast_char_constants<CharT>::minus;
CharT const plus = lcast_char_constants<CharT>::plus;
- bool has_minus = false;
+ bool const has_minus = Traits::eq(minus, *start);
/* We won`t use `start' any more, so no need in decrementing it after */
- if ( Traits::eq(minus,*start) )
- {
- ++start;
- has_minus = true;
- } else if ( Traits::eq( plus, *start ) )
- {
+ if (has_minus || Traits::eq(plus, *start)) {
++start;
}
@@ -1833,16 +1813,11 @@
CharT const minus = lcast_char_constants<CharT>::minus;
CharT const plus = lcast_char_constants<CharT>::plus;
typedef BOOST_DEDUCED_TYPENAME make_unsigned<Type>::type utype;
- utype out_tmp =0;
- bool has_minus = false;
+ utype out_tmp = 0;
+ bool const has_minus = Traits::eq(minus, *start);
/* We won`t use `start' any more, so no need in decrementing it after */
- if ( Traits::eq(minus,*start) )
- {
- ++start;
- has_minus = true;
- } else if ( Traits::eq(plus, *start) )
- {
+ if (has_minus || Traits::eq(plus, *start)) {
++start;
}
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