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fix all double to_string conversion failures by using sprintf method in all cases - closes #1741

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This commit is contained in:
Dane Springmeyer 2013-02-27 10:08:04 -05:00
parent f7a726445e
commit 00c2ff999d
2 changed files with 21 additions and 109 deletions
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123
src/conversions.cpp
View file

@ -152,6 +152,24 @@ bool string2float(const char * iter, const char * end, float & result)
return r && (iter == end);
}
// double conversion - here we use sprintf over karma to work
// around https://github.com/mapnik/mapnik/issues/1741
bool to_string(std::string & s, double val)
{
s.resize(s.capacity());
while (true)
{
size_t n2 = static_cast<size_t>(snprintf(&s[0], s.size()+1, "%g", val));
if (n2 <= s.size())
{
s.resize(n2);
break;
}
s.resize(n2);
}
return true;
}
#ifdef MAPNIK_KARMA_TO_STRING
bool to_string(std::string & str, int value)
@ -184,95 +202,6 @@ bool to_string(std::string & str, bool value)
return karma::generate(sink, value);
}
namespace detail {
template <typename T>
struct double_policy : boost::spirit::karma::real_policies<T>
{
typedef boost::spirit::karma::real_policies<T> base_type;
static int floatfield(T n) {
using namespace boost::spirit; // for traits
if (traits::test_zero(n))
return base_type::fmtflags::fixed;
T abs_n = traits::get_absolute_value(n);
return (abs_n >= 1e16 || abs_n < 1e-4)
? base_type::fmtflags::scientific : base_type::fmtflags::fixed;
}
static unsigned precision(T n) {
if ( n == 0.0 ) return 0;
using namespace boost::spirit; // for traits
return static_cast<unsigned>(15 - boost::math::trunc(log10(traits::get_absolute_value(n))));
}
template <typename OutputIterator>
static bool dot(OutputIterator& sink, T n, unsigned precision) {
if (n == 0.0) return true; // avoid trailing zeroes
return base_type::dot(sink, n, precision);
}
template <typename OutputIterator>
static bool fraction_part (OutputIterator& sink, T n
, unsigned precision_, unsigned precision)
{
// NOTE: copied from karma only to avoid trailing zeroes
// (maybe a bug ?)
// allow for ADL to find the correct overload for floor and log10
using namespace std;
using namespace boost::spirit; // for traits
using namespace boost::spirit::karma; // for char_inserter
if ( traits::test_zero(n) ) return true; // this part added to karma
// The following is equivalent to:
// generate(sink, right_align(precision, '0')[ulong], n);
// but it's spelled out to avoid inter-modular dependencies.
typename boost::remove_const<T>::type digits =
(traits::test_zero(n) ? 0 : floor(log10(n))) + 1;
bool r = true;
for (/**/; r && digits < precision_; digits = digits + 1)
r = char_inserter<>::call(sink, '0');
if (precision && r)
r = int_inserter<10>::call(sink, n);
return r;
}
template <typename CharEncoding, typename Tag, typename OutputIterator>
static bool exponent (OutputIterator& sink, long n)
{
// NOTE: copied from karma to force sign in exponent
const bool force_sign = true;
using namespace boost::spirit; // for traits
using namespace boost::spirit::karma; // for char_inserter, sign_inserter
unsigned long abs_n = traits::get_absolute_value(n);
bool r = char_inserter<CharEncoding, Tag>::call(sink, 'e') &&
sign_inserter::call(sink, traits::test_zero(n)
, traits::test_negative(n), force_sign);
// the C99 Standard requires at least two digits in the exponent
if (r && abs_n < 10)
r = char_inserter<CharEncoding, Tag>::call(sink, '0');
return r && int_inserter<10>::call(sink, abs_n);
}
};
}
bool to_string(std::string & str, double value)
{
namespace karma = boost::spirit::karma;
typedef karma::real_generator<double, detail::double_policy<double> > double_type;
std::back_insert_iterator<std::string> sink(str);
return karma::generate(sink, double_type(), value);
}
#else
bool to_string(std::string & s, int val)
@ -332,22 +261,6 @@ bool to_string(std::string & s, bool val)
return true;
}
bool to_string(std::string & s, double val)
{
s.resize(s.capacity());
while (true)
{
size_t n2 = static_cast<size_t>(snprintf(&s[0], s.size()+1, "%g", val));
if (n2 <= s.size())
{
s.resize(n2);
break;
}
s.resize(n2);
}
return true;
}
#endif
} // end namespace util

7
tests/cpp_tests/conversions_test.cpp
View file

@ -93,18 +93,18 @@ int main( int, char*[] )
BOOST_TEST_EQ( out, "1e-10" );
out.clear();
// critical failure when karam is used
to_string(out, double(-1.234e+16));
BOOST_TEST_EQ( out, "-1.234e+16" );
out.clear();
// critical failure when karam is used
// https://github.com/mapnik/mapnik/issues/1741
// https://github.com/mapbox/tilemill/issues/1456
to_string(out, double(8.3));
BOOST_TEST_EQ( out, "8.3" );
out.clear();
// non-critical failures if karma is used
/*
to_string(out, double(0.0001234567890123456));
// TODO: https://github.com/mapnik/mapnik/issues/1676
BOOST_TEST_EQ( out, "0.000123457" );
@ -189,7 +189,6 @@ int main( int, char*[] )
to_string(out, double(1234000000000000));
BOOST_TEST_EQ( out, "1.234e+15" );
out.clear();
*/
to_string(out, double(1e+16));
BOOST_TEST_EQ( out, "1e+16" );