Function AsciiStrToFloat

rEFIt_UEFI/libeg/FloatLib.cpp:231–297

RETURN_STATUS EFIAPI AsciiStrDecimalToUintnS ( IN CONST CHAR8 *String, OUT CHAR8 **EndPointer, OPTIONAL OUT UINTN *Data ); */

                         );
*/
RETURN_STATUS
AsciiStrToFloat(IN  CONST CHAR8              *String,
                OUT       CHAR8              **EndPointer,  OPTIONAL
                OUT       float              *Data)
{
  UINTN Temp = 0;
  INTN Sign = 1;
  float Mantissa, Ftemp;
  CHAR8* TmpStr = NULL;
  RETURN_STATUS Status = RETURN_SUCCESS;
  if (EndPointer != NULL) {
    *EndPointer = (CHAR8 *) String;
  }
  //
  // Ignore the pad spaces (space or tab)
  //
  while ((*String == ' ') || (*String == '\t')) {
    String++;
  }
  if (*String == '-') {
    Sign = -1;
    String++;
  } else if (*String == '+') {
    String++;
  }

  Status = AsciiStrDecimalToUintnS(String, &TmpStr, &Temp);
  Mantissa = (float)Temp;
  String = TmpStr;
  if (*String == '.') {
    String++;
    Temp = 0;
    Status = AsciiStrDecimalToUintnS(String, &TmpStr, &Temp);
    Ftemp = (float)Temp;
    while (String != TmpStr) {
      if (*String == '\0') {
        break;
      }
      Ftemp *= 0.1f;
      String++;
    }
    Mantissa += Ftemp;
  }
  
  if ((*String == 'E') || (*String == 'e')){
    INTN ExpSign = 1;
    String++;
    if (*String == '-') {
      ExpSign = -1;
      String++;
    } else if (*String == '+') {
      String++;
    }
    Temp = 0;
    Status = AsciiStrDecimalToUintnS(String, &TmpStr, &Temp);
    if ( Temp > MAX_INTN ) return RETURN_UNSUPPORTED;
    if (Status == RETURN_SUCCESS) {
      Ftemp = PowF(10.0f, ExpSign * (INTN)Temp); // cast to avoid warning