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Alternative handling of integer types relying on strto[u]ll
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46
src/json.hpp
46
src/json.hpp
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@ -9073,6 +9073,8 @@ basic_json_parser_66:
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note: in floating-point case strtod may parse
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note: in floating-point case strtod may parse
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past the token's end - this is not an error.
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past the token's end - this is not an error.
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any leading blanks are not handled.
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*/
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*/
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struct strtonum
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struct strtonum
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{
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{
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@ -9232,6 +9234,45 @@ basic_json_parser_66:
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return ok;
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return ok;
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}
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}
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#if 1 // parsing with strto[u]ll - easier to understand but slightly slower
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signed long long parse_integral(
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char** endptr,
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/*is_signed*/std::true_type) const
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{
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return std::strtoll(m_start, endptr, 10);
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}
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unsigned long long parse_integral(
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char** endptr,
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/*is_signed*/std::false_type) const
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{
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return std::strtoull(m_start, endptr, 10);
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}
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template<typename T>
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bool parse(T& value, /*is_integral=*/std::true_type) const
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{
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char* endptr = nullptr;
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errno = 0; // these are thread-local
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const auto x = parse_integral(&endptr, std::is_signed<T>());
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static_assert(std::is_signed<T>() // called right overload?
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== std::is_signed<decltype(x)>(), "");
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value = static_cast<T>(x);
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return x == static_cast<decltype(x)>(value) // x fits into destination T
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and (x != 0 or is_integral()) // strto[u]ll did nto fail
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and errno == 0 // strto[u]ll did not overflow
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and m_start < m_end // token was not empty
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and endptr == m_end // parsed entire token exactly
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and (x < 0) == (*m_start == '-'); // input was sign-compatible
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}
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#else // parsing integral types manually
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template<typename T>
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template<typename T>
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bool parse(T& value, /*is_integral=*/std::true_type) const
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bool parse(T& value, /*is_integral=*/std::true_type) const
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{
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{
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@ -9240,7 +9281,7 @@ basic_json_parser_66:
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if (beg == end)
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if (beg == end)
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{
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{
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return false;
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return false; // empty token
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}
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}
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const bool is_negative = (*beg == '-');
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const bool is_negative = (*beg == '-');
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@ -9261,7 +9302,7 @@ basic_json_parser_66:
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bool valid = beg < end // must have some digits;
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bool valid = beg < end // must have some digits;
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and ( T(-1) < 0 // type must be signed
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and ( T(-1) < 0 // type must be signed
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or !is_negative); // if value is negative
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or !is_negative); // ...if value is negative
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while (beg < end and valid)
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while (beg < end and valid)
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{
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{
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@ -9288,6 +9329,7 @@ basic_json_parser_66:
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// into positives is for edge cases, e.g. -2^63
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// into positives is for edge cases, e.g. -2^63
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return valid && (is_negative == (value < 0));
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return valid && (is_negative == (value < 0));
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}
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}
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#endif
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};
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};
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/*!
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/*!
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@ -8222,6 +8222,8 @@ class basic_json
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note: in floating-point case strtod may parse
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note: in floating-point case strtod may parse
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past the token's end - this is not an error.
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past the token's end - this is not an error.
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any leading blanks are not handled.
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*/
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*/
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struct strtonum
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struct strtonum
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{
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{
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@ -8381,6 +8383,45 @@ class basic_json
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return ok;
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return ok;
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}
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}
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#if 1 // parsing with strto[u]ll - easier to understand but slightly slower
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signed long long parse_integral(
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char** endptr,
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/*is_signed*/std::true_type) const
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{
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return std::strtoll(m_start, endptr, 10);
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}
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unsigned long long parse_integral(
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char** endptr,
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/*is_signed*/std::false_type) const
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{
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return std::strtoull(m_start, endptr, 10);
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}
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template<typename T>
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bool parse(T& value, /*is_integral=*/std::true_type) const
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{
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char* endptr = nullptr;
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errno = 0; // these are thread-local
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const auto x = parse_integral(&endptr, std::is_signed<T>());
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static_assert(std::is_signed<T>() // called right overload?
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== std::is_signed<decltype(x)>(), "");
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value = static_cast<T>(x);
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return x == static_cast<decltype(x)>(value) // x fits into destination T
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and (x != 0 or is_integral()) // strto[u]ll did nto fail
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and errno == 0 // strto[u]ll did not overflow
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and m_start < m_end // token was not empty
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and endptr == m_end // parsed entire token exactly
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and (x < 0) == (*m_start == '-'); // input was sign-compatible
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}
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#else // parsing integral types manually
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template<typename T>
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template<typename T>
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bool parse(T& value, /*is_integral=*/std::true_type) const
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bool parse(T& value, /*is_integral=*/std::true_type) const
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{
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{
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@ -8389,7 +8430,7 @@ class basic_json
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if (beg == end)
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if (beg == end)
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{
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{
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return false;
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return false; // empty token
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}
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}
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const bool is_negative = (*beg == '-');
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const bool is_negative = (*beg == '-');
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@ -8410,7 +8451,7 @@ class basic_json
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bool valid = beg < end // must have some digits;
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bool valid = beg < end // must have some digits;
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and ( T(-1) < 0 // type must be signed
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and ( T(-1) < 0 // type must be signed
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or !is_negative); // if value is negative
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or !is_negative); // ...if value is negative
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while (beg < end and valid)
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while (beg < end and valid)
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{
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{
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@ -8437,6 +8478,7 @@ class basic_json
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// into positives is for edge cases, e.g. -2^63
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// into positives is for edge cases, e.g. -2^63
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return valid && (is_negative == (value < 0));
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return valid && (is_negative == (value < 0));
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}
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}
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#endif
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};
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};
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/*!
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/*!
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