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Fix ostream << floating_point not correctly handling precision #1173

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Merged
StephanTLavavej merged 5 commits into from
Aug 22, 2020
Merged

Fix ostream << floating_point not correctly handling precision #1173

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b9e6aa9
Fix ostream << floating_point not correctly handling precision
statementreply Aug 18, 2020
98f8e7a
Add test cases
statementreply Aug 18, 2020
cd8d15c
Make _Float_put_desired_precision work for both raw precision() and _…
statementreply Aug 18, 2020
eda71ae
Add test coverage for long double
statementreply Aug 18, 2020
ae328d7
Fix copy paste error
statementreply Aug 19, 2020
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63 changes: 55 additions & 8 deletions stl/inc/xlocnum
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Original file line number Diff line number Diff line change
Expand Up @@ -1146,6 +1146,45 @@ __PURE_APPDOMAIN_GLOBAL locale::id num_get<_Elem, _InIt>::id;
#pragma clang diagnostic pop
#endif // __clang__

// STRUCT TEMPLATE _Hex_float_precision
template <class _Ty>
struct _Hex_float_precision;

template <>
struct _Hex_float_precision<double> {
// the number of hexits needed to represent (DBL_MANT_DIG - 1) bits after the radix point exactly
static constexpr int value = ((DBL_MANT_DIG - 1) + 3) / 4;
};

template <>
struct _Hex_float_precision<long double> {
// the number of hexits needed to represent (LDBL_MANT_DIG - 1) bits after the radix point exactly
static constexpr int value = ((LDBL_MANT_DIG - 1) + 3) / 4;
};

// FUNCTION TEMPLATE _Float_put_desired_precision
template <class _Ty>
int _Float_put_desired_precision(const streamsize _Precision, const ios_base::fmtflags _Float_flags) {
const bool _Is_hex = _Float_flags == (ios_base::fixed | ios_base::scientific);
if (_Is_hex) {
return _Hex_float_precision<_Ty>::value;
}

if (_Precision > 0) {
return static_cast<int>(_Precision);
} else if (_Precision == 0) {
const bool _Is_default_float = _Float_flags == 0;
if (_Is_default_float) {
return 1;
} else {
return 0;
}
} else {
constexpr int _Default_precision = 6;
return _Default_precision;
}
}

// CLASS TEMPLATE num_put
template <class _Elem, class _OutIt = ostreambuf_iterator<_Elem, char_traits<_Elem>>>
class num_put : public locale::facet { // facet for converting encoded numbers to text
Expand Down Expand Up @@ -1292,10 +1331,14 @@ protected:
_OutIt _Dest, ios_base& _Iosbase, _Elem _Fill, double _Val) const { // put formatted double to _Dest
string _Buf;
char _Fmt[8];
bool _Isfixed = (_Iosbase.flags() & ios_base::floatfield) == ios_base::fixed;
streamsize _Precision = _Iosbase.precision() <= 0 && !_Isfixed ? 6 : _Iosbase.precision(); // desired precision
size_t _Bufsize = static_cast<size_t>(_Precision);
if (_Isfixed && 1e10 < _CSTD fabs(_Val)) { // f or F format
const auto _Float_flags = _Iosbase.flags() & ios_base::floatfield;
const bool _Is_fixed = _Float_flags == ios_base::fixed;
const bool _Is_hex = _Float_flags == (ios_base::fixed | ios_base::scientific);
const streamsize _Precision = _Is_hex ? -1 : _Iosbase.precision(); // precision setting
const int _Desired_precision =
_Float_put_desired_precision<double>(_Precision, _Float_flags); // desired precision
size_t _Bufsize = static_cast<size_t>(_Desired_precision);
if (_Is_fixed && 1e10 < _CSTD fabs(_Val)) { // f or F format
int _Ptwo;
(void) _CSTD frexp(_Val, &_Ptwo);
_Bufsize += _CSTD abs(_Ptwo) * 30103L / 100000L;
Expand All @@ -1312,10 +1355,14 @@ protected:
_OutIt _Dest, ios_base& _Iosbase, _Elem _Fill, long double _Val) const { // put formatted long double to _Dest
string _Buf;
char _Fmt[8];
bool _Isfixed = (_Iosbase.flags() & ios_base::floatfield) == ios_base::fixed;
streamsize _Precision = _Iosbase.precision() <= 0 && !_Isfixed ? 6 : _Iosbase.precision(); // desired precision
size_t _Bufsize = static_cast<size_t>(_Precision);
if (_Isfixed && 1e10 < _CSTD fabsl(_Val)) { // f or F format
const auto _Float_flags = _Iosbase.flags() & ios_base::floatfield;
const bool _Is_fixed = _Float_flags == ios_base::fixed;
const bool _Is_hex = _Float_flags == (ios_base::fixed | ios_base::scientific);
const streamsize _Precision = _Is_hex ? -1 : _Iosbase.precision(); // precision setting
const int _Desired_precision =
_Float_put_desired_precision<long double>(_Precision, _Float_flags); // desired precision
size_t _Bufsize = static_cast<size_t>(_Desired_precision);
if (_Is_fixed && 1e10 < _CSTD fabsl(_Val)) { // f or F format
int _Ptwo;
(void) _CSTD frexpl(_Val, &_Ptwo);
_Bufsize += _CSTD abs(_Ptwo) * 30103L / 100000L;
Expand Down
102 changes: 101 additions & 1 deletion tests/tr1/tests/ostream1/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -213,9 +213,109 @@ void test_main() { // test basic workings of ostream definitions
outs << STD hexfloat << 2.0;
STD string ans = outs.str();
const char* buf = ans.c_str();
CHECK_STR(buf, "0x1.000p+1");
CHECK_STR(buf, "0x1.0000000000000p+1");
}

outs.precision(0);

outs.str("");
outs << STD defaultfloat << 1.5;
CHECK_STR(outs.str().c_str(), "2");

outs.str("");
outs << STD fixed << 1.0;
CHECK_STR(outs.str().c_str(), "1");

outs.str("");
outs << STD scientific << 2.0;
CHECK_STR(outs.str().c_str(), "2e+00");

outs.str("");
outs << STD hexfloat << 2.0;
CHECK_STR(outs.str().c_str(), "0x1.0000000000000p+1");

outs.precision(-1);

outs.str("");
outs << STD defaultfloat << 1.5;
CHECK_STR(outs.str().c_str(), "1.5");

outs.str("");
outs << STD fixed << 1.0;
CHECK_STR(outs.str().c_str(), "1.000000");

outs.str("");
outs << STD scientific << 2.0;
CHECK_STR(outs.str().c_str(), "2.000000e+00");

outs.str("");
outs << STD hexfloat << 2.0;
CHECK_STR(outs.str().c_str(), "0x1.0000000000000p+1");

outs.precision(-49);
outs.str("");
outs << STD fixed << 1.0;
CHECK_STR(outs.str().c_str(), "1.000000");

outs.precision(3);

outs.str("");
outs << STD defaultfloat << 1.5L;
CHECK_STR(outs.str().c_str(), "1.5");

outs.str("");
outs << STD fixed << 1.0L;
CHECK_STR(outs.str().c_str(), "1.000");

outs.str("");
outs << STD scientific << 2.0L;
CHECK_STR(outs.str().c_str(), "2.000e+00");

outs.str("");
outs << STD hexfloat << 2.0L;
CHECK_STR(outs.str().c_str(), "0x1.0000000000000p+1");

outs.precision(0);

outs.str("");
outs << STD defaultfloat << 1.5L;
CHECK_STR(outs.str().c_str(), "2");

outs.str("");
outs << STD fixed << 1.0L;
CHECK_STR(outs.str().c_str(), "1");

outs.str("");
outs << STD scientific << 2.0L;
CHECK_STR(outs.str().c_str(), "2e+00");

outs.str("");
outs << STD hexfloat << 2.0L;
CHECK_STR(outs.str().c_str(), "0x1.0000000000000p+1");

outs.precision(-1);

outs.str("");
outs << STD defaultfloat << 1.5L;
CHECK_STR(outs.str().c_str(), "1.5");

outs.str("");
outs << STD fixed << 1.0L;
CHECK_STR(outs.str().c_str(), "1.000000");

outs.str("");
outs << STD scientific << 2.0L;
CHECK_STR(outs.str().c_str(), "2.000000e+00");

outs.str("");
outs << STD hexfloat << 2.0L;
CHECK_STR(outs.str().c_str(), "0x1.0000000000000p+1");

outs.precision(-49);
outs.str("");
outs << STD fixed << 1.0L;
CHECK_STR(outs.str().c_str(), "1.000000");

// test Boolx inserter
const Boolx no(0), yes(1);
outs.str("");
Expand Down
102 changes: 101 additions & 1 deletion tests/tr1/tests/ostream2/test.cpp
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Expand Up @@ -208,7 +208,107 @@ void test_main() { // test basic workings of ostream definitions
outs << STD hexfloat << 2.0;
STD wstring ans = outs.str();
const wchar_t* buf = ans.c_str();
CHECK_WSTR(buf, L"0x1.000p+1");
CHECK_WSTR(buf, L"0x1.0000000000000p+1");

outs.precision(0);

outs.str(L"");
outs << STD defaultfloat << 1.5;
CHECK_WSTR(outs.str().c_str(), L"2");

outs.str(L"");
outs << STD fixed << 1.0;
CHECK_WSTR(outs.str().c_str(), L"1");

outs.str(L"");
outs << STD scientific << 2.0;
CHECK_WSTR(outs.str().c_str(), L"2e+00");

outs.str(L"");
outs << STD hexfloat << 2.0;
CHECK_WSTR(outs.str().c_str(), L"0x1.0000000000000p+1");

outs.precision(-1);

outs.str(L"");
outs << STD defaultfloat << 1.5;
CHECK_WSTR(outs.str().c_str(), L"1.5");

outs.str(L"");
outs << STD fixed << 1.0;
CHECK_WSTR(outs.str().c_str(), L"1.000000");

outs.str(L"");
outs << STD scientific << 2.0;
CHECK_WSTR(outs.str().c_str(), L"2.000000e+00");

outs.str(L"");
outs << STD hexfloat << 2.0;
CHECK_WSTR(outs.str().c_str(), L"0x1.0000000000000p+1");

outs.precision(-49);
outs.str(L"");
outs << STD fixed << 1.0;
CHECK_WSTR(outs.str().c_str(), L"1.000000");

outs.precision(3);

outs.str(L"");
outs << STD defaultfloat << 1.5L;
CHECK_WSTR(outs.str().c_str(), L"1.5");

outs.str(L"");
outs << STD fixed << 1.0L;
CHECK_WSTR(outs.str().c_str(), L"1.000");

outs.str(L"");
outs << STD scientific << 2.0L;
CHECK_WSTR(outs.str().c_str(), L"2.000e+00");

outs.str(L"");
outs << STD hexfloat << 2.0L;
CHECK_WSTR(outs.str().c_str(), L"0x1.0000000000000p+1");

outs.precision(0);

outs.str(L"");
outs << STD defaultfloat << 1.5L;
CHECK_WSTR(outs.str().c_str(), L"2");

outs.str(L"");
outs << STD fixed << 1.0L;
CHECK_WSTR(outs.str().c_str(), L"1");

outs.str(L"");
outs << STD scientific << 2.0L;
CHECK_WSTR(outs.str().c_str(), L"2e+00");

outs.str(L"");
outs << STD hexfloat << 2.0L;
CHECK_WSTR(outs.str().c_str(), L"0x1.0000000000000p+1");

outs.precision(-1);

outs.str(L"");
outs << STD defaultfloat << 1.5L;
CHECK_WSTR(outs.str().c_str(), L"1.5");

outs.str(L"");
outs << STD fixed << 1.0L;
CHECK_WSTR(outs.str().c_str(), L"1.000000");

outs.str(L"");
outs << STD scientific << 2.0L;
CHECK_WSTR(outs.str().c_str(), L"2.000000e+00");

outs.str(L"");
outs << STD hexfloat << 2.0L;
CHECK_WSTR(outs.str().c_str(), L"0x1.0000000000000p+1");

outs.precision(-49);
outs.str(L"");
outs << STD fixed << 1.0L;
CHECK_WSTR(outs.str().c_str(), L"1.000000");

// test Boolx inserter
const Boolx no(0), yes(1);
Expand Down