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feat(string): add parsing of arithmetic types from strings

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Redstone1024
2024-11-08 20:46:57 +08:00
parent 211a30525e
commit d8803880f1
3 changed files with 299 additions and 0 deletions
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191
Redcraft.Utility/Source/Public/String/Conversion.h.inl
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@ -58,6 +58,197 @@ struct TStringHelper
return false;
}
else if constexpr (CArithmetic<U>)
{
checkf(Fmt.IsEmpty(), TEXT("Formatted parsing of arithmetic types not implemented."));
// Skip leading white spaces.
while (!View.IsEmpty() && TChar<T>::IsSpace(View.Front())) View.RemovePrefix(1);
if (View.IsEmpty()) return false;
bool bNegative = false;
// Handle optional sign.
if (View.Front() == LITERAL(T, '+'))
{
View.RemovePrefix(1);
}
else if (View.Front() == LITERAL(T, '-'))
{
bNegative = true;
View.RemovePrefix(1);
}
// Handle boolean conversion.
else if constexpr (CSameAs<U, bool>)
{
bool bIsTrue = false;
bool bIsFalse = false;
bIsTrue |= View.StartsWith(LITERAL(T, "true")) || View.StartsWith(LITERAL(T, "True")) || View.StartsWith(LITERAL(T, "TRUE"));
bIsFalse |= View.StartsWith(LITERAL(T, "false")) || View.StartsWith(LITERAL(T, "False")) || View.StartsWith(LITERAL(T, "FALSE"));
if (bIsTrue) { View.RemovePrefix(4); Object = true; return true; }
if (bIsFalse) { View.RemovePrefix(5); Object = false; return true; }
}
// Handle floating-point conversion.
if constexpr (CFloatingPoint<U>)
{
bool bIsInfinity = false;
bool bIsNaN = false;
bIsInfinity |= View.StartsWith(LITERAL(T, "infinity")) || View.StartsWith(LITERAL(T, "Infinity")) || View.StartsWith(LITERAL(T, "INFINITY"));
bIsNaN |= View.StartsWith(LITERAL(T, "nan")) || View.StartsWith(LITERAL(T, "NaN")) || View.StartsWith(LITERAL(T, "NAN"));
if (bIsInfinity) { View.RemovePrefix(8); Object = bNegative ? -NAMESPACE_STD::numeric_limits<U>::infinity() : NAMESPACE_STD::numeric_limits<U>::infinity(); return true; }
if (bIsNaN) { View.RemovePrefix(3); Object = bNegative ? -NAMESPACE_STD::numeric_limits<U>::quiet_NaN() : NAMESPACE_STD::numeric_limits<U>::quiet_NaN(); return true; }
}
unsigned Base = 0;
// Auto detect base.
{
if (View.Num() >= 2 && View.Front() == LITERAL(T, '0'))
{
if (View[1] == LITERAL(T, 'x') || View[1] == LITERAL(T, 'X'))
{
Base = 16;
View.RemovePrefix(2);
}
else if (View[1] == LITERAL(T, 'b') || View[1] == LITERAL(T, 'B'))
{
Base = 2;
View.RemovePrefix(2);
}
else if (TChar<T>::IsDigit(View.Front(), 8))
{
Base = 8;
View.RemovePrefix(1);
}
else Base = 10;
}
else Base = 10;
}
// Parse the number.
auto ToNumber = [&View]<typename NumberType>(TInPlaceType<NumberType>, unsigned Base, NumberType Init = static_cast<NumberType>(0)) -> NumberType
{
NumberType Result = Init;
while (!View.IsEmpty() && (Base == 10 ? TChar<T>::IsDigit(View.Front()) : TChar<T>::IsDigit(View.Front(), Base)))
{
Result = static_cast<NumberType>(Result * Base + *TChar<T>::ToDigit(View.Front()));
View.RemovePrefix(1);
}
return Result;
};
// Handle integral conversion.
if constexpr (CIntegral<U>)
{
using UnsignedU = TMakeUnsigned<TConditional<!CSameAs<U, bool>, U, int>>;
if (View.IsEmpty()) return false;
// The integral number must start with a digit.
if (!TChar<T>::IsDigit(View.Front(), Base)) return false;
// Parse the integral number.
UnsignedU Number = ToNumber(InPlaceType<UnsignedU>, Base);
Object = static_cast<U>(bNegative ? -Number : Number);
return true;
}
// Handle floating-point conversion.
else if constexpr (CFloatingPoint<U>)
{
if (View.IsEmpty()) return false;
// The floating-point number must start with a digit or a dot.
if (!(TChar<T>::IsDigit(View.Front(), Base) || View.Front() == LITERAL(T, '.'))) return false;
size_t IntegralBeginNum = View.Num();
// Parse the integral number.
Object = ToNumber(InPlaceType<U>, Base);
size_t IntegralLength = IntegralBeginNum - View.Num();
// Parse the fractional number.
if (!View.IsEmpty() && View.Front() == LITERAL(T, '.'))
{
View.RemovePrefix(1);
U InvBase = 1 / static_cast<U>(Base);
size_t FractionBeginNum = View.Num();
Object = ToNumber(InPlaceType<U>, Base, Object);
size_t FractionLength = FractionBeginNum - View.Num();
Object *= NAMESPACE_STD::pow(InvBase, static_cast<U>(FractionLength));
}
else if (IntegralLength == 0) return false;
// For floating point numbers apply the symbols directly
Object = static_cast<U>(bNegative ? -Object : Object);
if (View.IsEmpty()) return true;
if (Base != 10 && Base != 16) return true;
bool bHasExponent = false;
bHasExponent |= Base == 10 && View.Front() == LITERAL(T, 'e');
bHasExponent |= Base == 10 && View.Front() == LITERAL(T, 'E');
bHasExponent |= Base == 16 && View.Front() == LITERAL(T, 'p');
bHasExponent |= Base == 16 && View.Front() == LITERAL(T, 'P');
if (!bHasExponent) return true;
View.RemovePrefix(1);
if (View.IsEmpty()) return false;
// Parse the exponent number.
{
bool bNegativeExponent = false;
if (View.Front() == LITERAL(T, '+'))
{
View.RemovePrefix(1);
}
else if (View.Front() == LITERAL(T, '-'))
{
bNegativeExponent = true;
View.RemovePrefix(1);
}
// The exponent number must start with a digit.
if (!TChar<T>::IsDigit(View.Front())) return false;
U Exponent = ToNumber(InPlaceType<U>, 10);
Exponent = bNegativeExponent ? -Exponent : Exponent;
Object *= static_cast<U>(NAMESPACE_STD::pow(static_cast<U>(Base == 16 ? 2 : 10), Exponent));
}
return true;
}
else static_assert(sizeof(U) == -1, "Unsupported arithmetic type");
return false;
}
return false;
}

1
Redcraft.Utility/Source/Public/Testing/StringTesting.h
View File

@ -12,6 +12,7 @@ REDCRAFTUTILITY_API void TestString();
REDCRAFTUTILITY_API void TestChar();
REDCRAFTUTILITY_API void TestStringView();
REDCRAFTUTILITY_API void TestTemplateString();
REDCRAFTUTILITY_API void TestStringConversion();
NAMESPACE_END(Testing)