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Use tools from Boost.Spirit to parse & write numbers without locale
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Fixes #6
Added benefit that float parsing/writing is now more strict and JSON
compliant (no inf/nan)
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@chrismanning
chrismanning committed Aug 24, 2014
1 parent 1f8cb9f commit b557c9f
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Showing 2 changed files with 74 additions and 38 deletions.
74 changes: 49 additions & 25 deletions include/jbson/json_reader.hpp
View file
Expand Up @@ -21,6 +21,8 @@ JBSON_PUSH_DISABLE_DOCUMENTATION_WARNING
#include <boost/exception/exception.hpp>
#include <boost/spirit/home/support/iterators/line_pos_iterator.hpp>
#include <boost/io/ios_state.hpp>
#include <boost/spirit/home/qi/numeric/numeric_utils.hpp>
#include <boost/spirit/home/qi/numeric/real.hpp>
JBSON_CLANG_POP_WARNINGS

#include "document.hpp"
Expand Down Expand Up @@ -798,6 +800,13 @@ OutputIterator json_reader::parse_escape(line_pos_iterator<ForwardIterator>& fir
return out;
}

template <typename Num> struct real_parse_policy : boost::spirit::qi::strict_real_policies<Num> {
static bool const allow_leading_dot = false;
static bool const allow_trailing_dot = false;
template <typename... Args> static bool parse_nan(Args&&...) { return false; }
template <typename... Args> static bool parse_inf(Args&&...) { return false; }
};

template <typename ForwardIterator, typename OutputIterator>
std::tuple<OutputIterator, element_type> json_reader::parse_number(line_pos_iterator<ForwardIterator>& first_,
const line_pos_iterator<ForwardIterator>& last_,
Expand All @@ -806,9 +815,26 @@ std::tuple<OutputIterator, element_type> json_reader::parse_number(line_pos_iter

if(!detail::isdigit(*first_) && *first_ != '-')
BOOST_THROW_EXCEPTION(make_parse_exception(json_error_num::unexpected_token, first_, last_, "number"));
const auto last = std::find_if_not(first_, last_, [](char c) {
return detail::isdigit(c) || c == '.' || c == '+' || c == '-' || c == 'e' || c == 'E';
});
bool has_decimal = false;
line_pos_iterator<ForwardIterator> last;
std::tie(has_decimal, last) = [this](auto first, auto last) {
bool dec = false;
for(; first != last; first++) {
auto c = *first;
if(c == '.') {
if(!dec)
dec = true;
else
BOOST_THROW_EXCEPTION(
make_parse_exception(json_error_num::unexpected_token, first, last, "number"));
continue;
} else if(!(detail::isdigit(c) || c == '+' || c == '-' || c == 'e' || c == 'E'))
break;
}
return std::make_tuple(dec, line_pos_iterator<ForwardIterator>(first));
}(first_, last_);

assert(has_decimal == (std::find(first_.base(), last.base(), '.') != last.base()));

const auto buf_len = std::distance(first_.base(), last.base());
char* buf = (char*)alloca(buf_len + 1);
Expand All @@ -821,37 +847,35 @@ std::tuple<OutputIterator, element_type> json_reader::parse_number(line_pos_iter
BOOST_THROW_EXCEPTION(make_parse_exception(json_error_num::unexpected_token, first_, last_, "number"));
auto type = element_type::null_element;

char* pos;
const int64_t val = std::strtoll(buf, &pos, 10);

if(pos == buf || pos != buf_end || errno == ERANGE) {
errno = 0;
char* pos;
const double val = std::strtod(buf, &pos);

if(val == HUGE_VALL || pos == buf || pos != buf_end)
if(has_decimal) {
double val;
static const boost::spirit::qi::any_real_parser<double, real_parse_policy<double>> dbl_parser{};
auto ok = dbl_parser.parse(buf, buf_end, boost::spirit::unused, boost::spirit::unused, val);
if(!ok)
BOOST_THROW_EXCEPTION(make_parse_exception(json_error_num::unexpected_token, first_, last_, "number"));

std::advance(first_, buf_len);

assert(out >= m_data.begin() && out <= m_data.end());
detail::serialise(m_data, out, val);
type = element_type::double_element;
return std::make_tuple(out, type);
} else {
int64_t val = 0;
auto ok = boost::spirit::qi::extract_int<int64_t, 10, 1, -1>::call(buf, buf_end, val);
if(!ok)
BOOST_THROW_EXCEPTION(make_parse_exception(json_error_num::unexpected_token, first_, last_, "number"));

if(val > std::numeric_limits<int32_t>::min() && val < std::numeric_limits<int32_t>::max()) {
assert(out >= m_data.begin() && out <= m_data.end());
detail::serialise(m_data, out, static_cast<int32_t>(val));
type = element_type::int32_element;
} else {
assert(out >= m_data.begin() && out <= m_data.end());
detail::serialise(m_data, out, val);
type = element_type::int64_element;
}
}

std::advance(first_, buf_len);

if(val > std::numeric_limits<int32_t>::min() && val < std::numeric_limits<int32_t>::max()) {
assert(out >= m_data.begin() && out <= m_data.end());
detail::serialise(m_data, out, static_cast<int32_t>(val));
type = element_type::int32_element;
} else {
assert(out >= m_data.begin() && out <= m_data.end());
detail::serialise(m_data, out, val);
type = element_type::int64_element;
}

return std::make_tuple(out, type);
}

Expand Down
38 changes: 25 additions & 13 deletions include/jbson/json_writer.hpp
View file
Expand Up @@ -14,6 +14,7 @@
JBSON_PUSH_DISABLE_DOCUMENTATION_WARNING
#include <boost/utility/string_ref.hpp>
#include <boost/range/as_literal.hpp>
#include <boost/spirit/home/karma/numeric.hpp>
JBSON_CLANG_POP_WARNINGS

#include "element.hpp"
Expand All @@ -40,24 +41,35 @@ namespace {

template <typename T, typename OutputIterator>
std::decay_t<OutputIterator> stringify(T&& v, OutputIterator out,
std::enable_if_t<std::is_integral<std::decay_t<T>>::value>* = nullptr) {
if(std::is_same<T, bool>::value)
return boost::range::copy(boost::as_literal(!!v ? "true" : "false"), out);
std::array<char, std::numeric_limits<T>::digits10 + 2> int_str;
auto n = std::snprintf(int_str.data(), int_str.size(), "%zd", static_cast<ptrdiff_t>(v));
assert(n > 0);
assert(static_cast<size_t>(n) <= int_str.size());
return boost::range::copy(boost::string_ref{int_str.data(), static_cast<size_t>(n)}, out);
std::enable_if_t<std::is_same<std::decay_t<T>, bool>::value>* = nullptr) {
return boost::range::copy(boost::as_literal(!!v ? "true" : "false"), out);
}

template <typename T, typename OutputIterator>
std::decay_t<OutputIterator> stringify(T&& v, OutputIterator out,
std::enable_if_t<std::is_integral<std::decay_t<T>>::value>* = nullptr,
std::enable_if_t<!std::is_same<std::decay_t<T>, bool>::value> * = nullptr) {
auto ok = boost::spirit::karma::int_inserter<10>::call(out, (std::make_signed_t<T>)v);
assert(ok);
(void)ok;

return out;
}

template <typename Num> struct real_gen_policy : boost::spirit::karma::real_policies<Num> {
static unsigned precision(Num) { return 8; }
template <typename... Args> static bool nan(Args&&...) { return false; }
template <typename... Args> static bool inf(Args&&...) { return false; }
};

template <typename T, typename OutputIterator>
std::decay_t<OutputIterator> stringify(T&& v, OutputIterator out,
std::enable_if_t<std::is_floating_point<std::decay_t<T>>::value>* = nullptr) {
std::array<char, std::numeric_limits<T>::digits10 + 2> float_str;
auto n = std::snprintf(float_str.data(), float_str.size(), "%.8g", v);
assert(n > 0);
assert(static_cast<size_t>(n) <= float_str.size());
out = boost::range::copy(boost::string_ref{float_str.data(), static_cast<size_t>(n)}, out);
static const real_gen_policy<T> policy{};
auto ok = boost::spirit::karma::real_inserter<T, real_gen_policy<T>>::call(out, v, policy);
assert(ok);
(void)ok;

return out;
}

Expand Down

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