IntegerToStringConversion.h [plain text]
#pragma once
#include <wtf/text/LChar.h>
namespace WTF {
enum PositiveOrNegativeNumber { PositiveNumber, NegativeNumber };
template<typename> struct IntegerToStringConversionTrait;
template<typename T, typename UnsignedIntegerType, PositiveOrNegativeNumber NumberType, typename AdditionalArgumentType>
static typename IntegerToStringConversionTrait<T>::ReturnType numberToStringImpl(UnsignedIntegerType number, AdditionalArgumentType additionalArgument)
{
LChar buf[sizeof(UnsignedIntegerType) * 3 + 1];
LChar* end = std::end(buf);
LChar* p = end;
do {
*--p = static_cast<LChar>((number % 10) + '0');
number /= 10;
} while (number);
if (NumberType == NegativeNumber)
*--p = '-';
return IntegerToStringConversionTrait<T>::flush(p, static_cast<unsigned>(end - p), additionalArgument);
}
template<typename T, typename SignedIntegerType>
inline typename IntegerToStringConversionTrait<T>::ReturnType numberToStringSigned(SignedIntegerType number, typename IntegerToStringConversionTrait<T>::AdditionalArgumentType* additionalArgument = nullptr)
{
if (number < 0)
return numberToStringImpl<T, typename std::make_unsigned_t<SignedIntegerType>, NegativeNumber>(-number, additionalArgument);
return numberToStringImpl<T, typename std::make_unsigned_t<SignedIntegerType>, PositiveNumber>(number, additionalArgument);
}
template<typename T, typename UnsignedIntegerType>
inline typename IntegerToStringConversionTrait<T>::ReturnType numberToStringUnsigned(UnsignedIntegerType number, typename IntegerToStringConversionTrait<T>::AdditionalArgumentType* additionalArgument = nullptr)
{
return numberToStringImpl<T, UnsignedIntegerType, PositiveNumber>(number, additionalArgument);
}
template<typename CharacterType, typename UnsignedIntegerType, PositiveOrNegativeNumber NumberType>
static void writeIntegerToBufferImpl(UnsignedIntegerType number, CharacterType* destination)
{
static_assert(!std::is_same_v<bool, std::remove_cv_t<UnsignedIntegerType>>, "'bool' not supported");
LChar buf[sizeof(UnsignedIntegerType) * 3 + 1];
LChar* end = std::end(buf);
LChar* p = end;
do {
*--p = static_cast<LChar>((number % 10) + '0');
number /= 10;
} while (number);
if (NumberType == NegativeNumber)
*--p = '-';
while (p < end)
*destination++ = static_cast<CharacterType>(*p++);
}
template<typename CharacterType, typename IntegerType>
inline void writeIntegerToBuffer(IntegerType integer, CharacterType* destination)
{
static_assert(std::is_integral_v<IntegerType>);
if constexpr (std::is_same_v<IntegerType, bool>)
return writeIntegerToBufferImpl<CharacterType, uint8_t, PositiveNumber>(integer ? 1 : 0, destination);
else if constexpr (std::is_signed_v<IntegerType>) {
if (integer < 0)
return writeIntegerToBufferImpl<CharacterType, typename std::make_unsigned_t<IntegerType>, NegativeNumber>(-integer, destination);
return writeIntegerToBufferImpl<CharacterType, typename std::make_unsigned_t<IntegerType>, PositiveNumber>(integer, destination);
} else
return writeIntegerToBufferImpl<CharacterType, IntegerType, PositiveNumber>(integer, destination);
}
template<typename UnsignedIntegerType, PositiveOrNegativeNumber NumberType>
static unsigned lengthOfIntegerAsStringImpl(UnsignedIntegerType number)
{
unsigned length = 0;
do {
++length;
number /= 10;
} while (number);
if (NumberType == NegativeNumber)
++length;
return length;
}
template<typename IntegerType>
inline unsigned lengthOfIntegerAsString(IntegerType integer)
{
static_assert(std::is_integral_v<IntegerType>);
if constexpr (std::is_same_v<IntegerType, bool>) {
UNUSED_PARAM(integer);
return 1;
}
else if constexpr (std::is_signed_v<IntegerType>) {
if (integer < 0)
return lengthOfIntegerAsStringImpl<typename std::make_unsigned_t<IntegerType>, NegativeNumber>(-integer);
return lengthOfIntegerAsStringImpl<typename std::make_unsigned_t<IntegerType>, PositiveNumber>(integer);
} else
return lengthOfIntegerAsStringImpl<IntegerType, PositiveNumber>(integer);
}
}