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Fix for stream reading: handles more formats now, including things like CSV lists.

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This commit is contained in:
jzmaddock
2015-03-11 19:25:14 +00:00
parent 19eb190929
commit 51a320e98a
1 changed files with 64 additions and 6 deletions
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70
include/boost/multiprecision/number.hpp
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@@ -24,6 +24,7 @@
#include <boost/multiprecision/traits/is_restricted_conversion.hpp>
#include <istream> // stream operators
#include <cstdio> // EOF
#include <cctype> // isspace
namespace boost{ namespace multiprecision{
@@ -1706,6 +1707,48 @@ inline std::ostream& operator << (std::ostream& os, const expression<tag, A1, A2
value_type temp(r);
return os << temp;
}
//
// What follows is the input streaming code: this is not "proper" iostream code at all
// but that's fiendishly hard to write when dealing with multiple backends all
// with different requirements... yes we could deligate this to the backend author...
// but we really want backends to be EASY to write!
// For now just pull in all the characters that could possibly form the number
// and let the backend's string parser make use of it. This fixes most use cases
// including CSV type formats such as those used by the Random lib.
//
inline std::string read_string_while(std::istream& is, std::string const& permitted_chars)
{
std::ios_base::iostate state = std::ios_base::goodbit;
const std::istream::sentry sentry_check(is);
std::string result;
if(sentry_check)
{
int c = is.rdbuf()->sgetc();
for(;; c = is.rdbuf()->snextc())
if(std::istream::traits_type::eq_int_type(std::istream::traits_type::eof(), c))
{ // end of file:
state |= std::ios_base::eofbit;
break;
}
else if(permitted_chars.find_first_of(std::istream::traits_type::to_char_type(c)) == std::string::npos)
{
// Invalid numeric character, stop reading:
is.rdbuf()->sputbackc(c);
break;
}
else
{
result.append(1, std::istream::traits_type::to_char_type(c));
}
}
if(!result.size())
state |= std::ios_base::failbit;
is.setstate(state);
return result;
}
} // namespace detail
@@ -1715,12 +1758,27 @@ inline std::istream& operator >> (std::istream& is, number<Backend, ExpressionTe
bool hex_format = (is.flags() & std::ios_base::hex) == std::ios_base::hex;
bool oct_format = (is.flags() & std::ios_base::oct) == std::ios_base::oct;
std::string s;
is >> s;
if(hex_format && (number_category<Backend>::value == number_kind_integer) && ((s[0] != '0') || (s[1] != 'x')))
s.insert(s.find_first_not_of("+-"), "0x");
if(oct_format && (number_category<Backend>::value == number_kind_integer) && (s[0] != '0'))
s.insert(s.find_first_not_of("+-"), "0");
r.assign(s);
switch(boost::multiprecision::number_category<number<Backend, ExpressionTemplates> >::value)
{
case boost::multiprecision::number_kind_integer:
s = detail::read_string_while(is, "+-0xX123456789");
break;
case boost::multiprecision::number_kind_floating_point:
s = detail::read_string_while(is, "+-eE.0123456789infINFnanNANinfinityINFINITY");
break;
default:
is >> s;
}
if(s.size())
{
if(hex_format && (number_category<Backend>::value == number_kind_integer) && ((s[0] != '0') || (s[1] != 'x')))
s.insert(s.find_first_not_of("+-"), "0x");
if(oct_format && (number_category<Backend>::value == number_kind_integer) && (s[0] != '0'))
s.insert(s.find_first_not_of("+-"), "0");
r.assign(s);
}
else if(!is.fail())
is.setstate(std::istream::failbit);
return is;
}