GammaLib

The GPar interface should handle the following special parameter values:

• INDEF
• NONE
• INF
• INFINITY
• NAN

See the corresponding APE code (ape_utils.c):

/* Strictly convert input string to output bool, ignoring leading/trailing white space, and flagging every possible error. */
static int string2bool(const char * input, char * result) {
  int status = eOK;
  if (0 != result) {
    *result = 0;
    if (0 != input) {
      /* Truncate white space from input string. */
      char * copy = truncate_white_space(input);

      /* Compare input string (case insensitive) to various boolean expressions. */
      if (0 == ci_strcmp(copy, "true") || 0 == ci_strcmp(copy, "t") ||
        0 == ci_strcmp(copy, "yes") || 0 == ci_strcmp(copy, "y")) {
        *result = 1;
      } else if (0 == ci_strcmp(copy, "false") || 0 == ci_strcmp(copy, "f") ||
        0 == ci_strcmp(copy, "no") || 0 == ci_strcmp(copy, "n")) {
        *result = 0;
      } else {
        /* String does not contain a valid bool expression. */
        status = eConversionError;
      }

      /* Clean up. */
      free(copy); copy = 0;
    } else {
      status = eNullPointer;
    }
  } else {
    status = eNullPointer;
  }
  return status;
}

/* Strictly convert input string to output double, ignoring leading/trailing white space, and flagging every possible error. */
static int string2double(const char * input, double * result) {
  int status = eOK;
  if (0 != result) {
    *result = 0.;
    if (0 != input) {
      char * remainder = 0;
      /* Skip leading white space. */
      while (0 != isspace(*input)) ++input;

      if ('\0' == *input || 0 == ci_strcmp(input, "indef") || 0 == ci_strcmp(input, "none") || 0 == ci_strcmp(input, "undef") ||
        0 == ci_strcmp(input, "undefined")) {
        status = eUndefinedValue;
      } else if (0 == ci_strcmp(input, "inf") || 0 == ci_strcmp(input, "infinity") || 0 == ci_strcmp(input, "nan")) {
        status = eNan;
      } else {
        errno = 0;
        *result = strtod(input, &remainder);
        if (ERANGE == errno) {
          if (0. == *result) status = eUnderflow;
          else status = eOverflow;
        } else if (0 != remainder && '\0' != *remainder) {
          /* Ignore trailing whitespace; the C standard is not specific about whether it's returned or eaten by the conversion. */
          while (0 != isspace(*remainder)) ++remainder;
          if ('\0' != *remainder) status = eStringRemainder;
          /* else conversion succeeded. */
        } else {
          /* Conversion succeeded! */
        }
      }
    } else {
      status = eNullPointer;
    }
  } else {
    status = eNullPointer;
  }
  return status;
}

/* Strictly convert input string to output long, ignoring leading/trailing white space, and flagging every possible error. */
static int string2long(const char * input, long * result) {
  int status = eOK;
  if (0 != result) {
    *result = 0;
    if (0 != input) {
      char * remainder = 0;
      errno = 0;
      /* Skip leading white space. */
      while (0 != isspace(*input)) ++input;

      if ('\0' == *input || 0 == ci_strcmp(input, "indef") || 0 == ci_strcmp(input, "none") || 0 == ci_strcmp(input, "undef") ||
        0 == ci_strcmp(input, "undefined")) {
        status = eUndefinedValue;
      } else if (0 == ci_strcmp(input, "inf") || 0 == ci_strcmp(input, "infinity") || 0 == ci_strcmp(input, "nan")) {
        *result = LONG_MAX;
      } else {
        *result = strtol(input, &remainder, 0);
        if (ERANGE == errno) {
          if (LONG_MIN == *result) status = eUnderflow;
          else if (LONG_MAX == *result) status = eOverflow;
          else status = eConversionError;
        } else if (0 != remainder && '\0' != *remainder) {
          /* Ignore trailing whitespace; the C standard is not specific about whether it's returned or eaten by the conversion. */
          while (0 != isspace(*remainder)) ++remainder;
          if ('\0' != *remainder) status = eStringRemainder;
          /* else conversion succeeded. */
        } else {
          /* Conversion succeeded! */
        }
      }
    } else {
      status = eNullPointer;
    }
  } else {
    status = eNullPointer;
  }
  return status;
}