longlong my_strtoll10()

in mysql_strings/my_strtoll10.cc [86:214]

• 104 lines of code
• 43 McCabe index (conditional complexity)

longlong my_strtoll10(const char *nptr, const char **endptr, int *error) {
  const char *s, *end, *start, *n_end, *true_end;
  const char *dummy;
  uchar c;
  unsigned long i, j, k;
  ulonglong li;
  int negative;
  ulong cutoff, cutoff2, cutoff3;

  s = nptr;
  /* If fixed length string */
  if (endptr) {
    end = *endptr;
    while (s != end && (*s == ' ' || *s == '\t')) s++;
    if (s == end) goto no_conv;
  } else {
    endptr = &dummy; /* Easier end test */
    while (*s == ' ' || *s == '\t') s++;
    if (!*s) goto no_conv;
    /* This number must be big to guard against a lot of pre-zeros */
    end = s + 65535; /* Can't be longer than this */
  }

  /* Check for a sign.	*/
  negative = 0;
  if (*s == '-') {
    *error = -1; /* Mark as negative number */
    negative = 1;
    if (++s == end) goto no_conv;
    cutoff = MAX_NEGATIVE_NUMBER / LFACTOR2;
    cutoff2 = (MAX_NEGATIVE_NUMBER % LFACTOR2) / 100;
    cutoff3 = MAX_NEGATIVE_NUMBER % 100;
  } else {
    *error = 0;
    if (*s == '+') {
      if (++s == end) goto no_conv;
    }
    cutoff = ULLONG_MAX / LFACTOR2;
    cutoff2 = ULLONG_MAX % LFACTOR2 / 100;
    cutoff3 = ULLONG_MAX % 100;
  }

  /* Handle case where we have a lot of pre-zero */
  if (*s == '0') {
    i = 0;
    do {
      if (++s == end) goto end_i; /* Return 0 */
    } while (*s == '0');
    n_end = s + INIT_CNT;
  } else {
    /* Read first digit to check that it's a valid number */
    if ((c = (*s - '0')) > 9) goto no_conv;
    i = c;
    n_end = ++s + INIT_CNT - 1;
  }

  /* Handle first 9 digits and store them in i */
  if (n_end > end) n_end = end;
  for (; s != n_end; s++) {
    if ((c = (*s - '0')) > 9) goto end_i;
    i = i * 10 + c;
  }
  if (s == end) goto end_i;

  /* Handle next 9 digits and store them in j */
  j = 0;
  start = s; /* Used to know how much to shift i */
  n_end = true_end = s + INIT_CNT;
  if (n_end > end) n_end = end;
  do {
    if ((c = (*s - '0')) > 9) goto end_i_and_j;
    j = j * 10 + c;
  } while (++s != n_end);
  if (s == end) {
    if (s != true_end) goto end_i_and_j;
    goto end3;
  }
  if ((c = (*s - '0')) > 9) goto end3;

  /* Handle the next 1 or 2 digits and store them in k */
  k = c;
  if (++s == end || (c = (*s - '0')) > 9) goto end4;
  k = k * 10 + c;
  *endptr = ++s;

  /* number string should have ended here */
  if (s != end && (c = (*s - '0')) <= 9) goto overflow;

  /* Check that we didn't get an overflow with the last digit */
  if (i > cutoff ||
      (i == cutoff && (j > cutoff2 || (j == cutoff2 && k > cutoff3))))
    goto overflow;
  li = i * LFACTOR2 + (ulonglong)j * 100 + k;
  return (longlong)li;

overflow: /* *endptr is set here */
  *error = MY_ERRNO_ERANGE;
  return negative ? LLONG_MIN : (longlong)ULLONG_MAX;

end_i:
  *endptr = s;
  return (negative ? ((longlong) - (long)i) : (longlong)i);

end_i_and_j:
  li = (ulonglong)i * lfactor[(uint)(s - start)] + j;
  *endptr = s;
  return (negative ? -((longlong)li) : (longlong)li);

end3:
  li = (ulonglong)i * LFACTOR + (ulonglong)j;
  *endptr = s;
  return (negative ? -((longlong)li) : (longlong)li);

end4:
  li = (ulonglong)i * LFACTOR1 + (ulonglong)j * 10 + k;
  *endptr = s;
  if (negative) {
    if (li > MAX_NEGATIVE_NUMBER) goto overflow;
    if (li == MAX_NEGATIVE_NUMBER) return LLONG_MIN;
    return -((longlong)li);
  }
  return (longlong)li;

no_conv:
  /* There was no number to convert.  */
  *error = MY_ERRNO_EDOM;
  *endptr = nptr;
  return 0;
}