Method rd_string

include/win/boost/multiprecision/cpp_dec_float.hpp:1889–2160

template <unsigned Digits10, class ExponentType, class Allocator>
bool cpp_dec_float<Digits10, ExponentType, Allocator>::rd_string(const char* const s)
{
   try{

   std::string str(s);

   // TBD: Using several regular expressions may significantly reduce
   // the code complexity (and perhaps the run-time) of rd_string().

   // Get a possible exponent and remove it.
   exp = static_cast<ExponentType>(0);

   std::size_t pos;

   if( ((pos = str.find('e')) != std::string::npos)
      || ((pos = str.find('E')) != std::string::npos)
      )
   {
      // Remove the exponent part from the string.
      exp = boost::lexical_cast<ExponentType>(static_cast<const char*>(str.c_str() + (pos + 1u)));
      str = str.substr(static_cast<std::size_t>(0u), pos);
   }

   // Get a possible +/- sign and remove it.
   neg = false;

   if(str.size())
   {
      if(str[0] == '-')
      {
         neg = true;
         str.erase(0, 1);
      }
      else if(str[0] == '+')
      {
         str.erase(0, 1);
      }
   }
   //
   // Special cases for infinities and NaN's:
   //
   if((str == "inf") || (str == "INF") || (str == "infinity") || (str == "INFINITY"))
   {
      if(neg)
      {
         *this = this->inf();
         this->negate();
      }
      else
         *this = this->inf();
      return true;
   }
   if((str.size() >= 3) && ((str.substr(0, 3) == "nan") || (str.substr(0, 3) == "NAN") || (str.substr(0, 3) == "NaN")))
   {
      *this = this->nan();
      return true;
   }