internal Namespace Reference

Namespaces
namespace	dtoa_impl
namespace	itoa_impl
namespace	x11

Classes
class	ConnectionProxy
	Host's proxy object between connection points. More...
class	PlugFrame
	Dispatches window resize events from VST PlugView to the wxWindow. More...

Functions
template<typename T >
ToCharsResult	float_to_chars (char *first, char *last, T value, int digitsAfterDecimalPoint)

Function Documentation

float_to_chars()

template<typename T >

ToCharsResult internal::float_to_chars	(	char *	first,
		char *	last,
		T	value,
		int	digitsAfterDecimalPoint
	)

The format of the resulting decimal representation is similar to printf's g format. Returns an iterator pointing past-the-end of the decimal representation.

Note

The input number must be finite, i.e. NaN's and Inf's are not supported.

The buffer must be large enough.

The result is NOT null-terminated.

Definition at line 1178 of file ToChars.cpp.

{
   if (first >= last || first == nullptr)
      return { last, std::errc::value_too_large };
 
   if (value == 0)
   {
      *first++ = '0';
 
      return { first, std::errc() };
   }
 
   if (std::signbit(value))
   {
      value = -value;
      *first++ = '-';
   }
   // Compute v = buffer * 10^decimal_exponent.
   // The decimal digits are stored in the buffer, which needs to be interpreted
   // as an unsigned decimal integer.
   // len is the length of the buffer, i.e. the number of decimal digits.
   int len = 0;
   int decimal_exponent = 0;
   if (!dtoa_impl::grisu2(first, last, len, decimal_exponent, value))
      return { last, std::errc::value_too_large };
   // Format the buffer like printf("%.*g", prec, value)
   const int kMinExp = digitsAfterDecimalPoint < 0 ? -4 : -digitsAfterDecimalPoint;
   constexpr int kMaxExp = std::numeric_limits<double>::digits10;
 
   // Audacity specific extension imitating Internat::ToDisplayString
   // for a consistent behavior
   if (digitsAfterDecimalPoint >= 0)
   {
      if (len + decimal_exponent > 0 && -decimal_exponent > digitsAfterDecimalPoint)
      {
         const int difference = digitsAfterDecimalPoint + decimal_exponent;
         decimal_exponent = -digitsAfterDecimalPoint;
         len += difference;
      }
   }
 
   return dtoa_impl::format_buffer(
      first, last, len, decimal_exponent, kMinExp, kMaxExp);
}

References internal::dtoa_impl::format_buffer(), and internal::dtoa_impl::grisu2().

Referenced by ToChars().

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