incubator-nuttx/libs/libc/stdlib/lib_strtoull.c

136 lines
3.7 KiB
C

/****************************************************************************
* libs/libc/stdlib/lib_strtoull.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/compiler.h>
#include <stdlib.h>
#include <errno.h>
#include "libc.h"
#ifdef CONFIG_HAVE_LONG_LONG
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: strtoull
*
* Description:
* The strtoull() function converts the initial part of the string in
* nptr to a long unsigned integer value according to the given base, which
* must be between 2 and 36 inclusive, or be the special value 0.
*
* Returned Value:
* - The converted value, if the base and number are valid
* - 0 if an error occurs, and set errno to:
* * EINVAL if base < 2 or base > 36
* - ULLONG_MAX if an overflow occurs, and set errno to:
* * ERANGE if the number cannot be represented using unsigned long long
*
****************************************************************************/
unsigned long long strtoull(FAR const char *nptr,
FAR char **endptr, int base)
{
unsigned long long accum = 0;
unsigned long long limit;
int value;
int last_digit;
char sign = 0;
if (nptr)
{
/* Skip leading spaces */
lib_skipspace(&nptr);
/* Check for leading + or - already done for strtol */
if (*nptr == '-' || *nptr == '+')
{
sign = *nptr;
nptr++;
}
/* Check for unspecified or incorrect base */
base = lib_checkbase(base, &nptr);
if (base < 0)
{
set_errno(EINVAL);
accum = 0;
}
else
{
limit = ULLONG_MAX / base;
last_digit = ULLONG_MAX % base;
/* Accumulate each "digit" */
while (lib_isbasedigit(*nptr, base, &value))
{
/* Check for overflow */
if (accum > limit || (accum == limit && value > last_digit))
{
set_errno(ERANGE);
accum = ULLONG_MAX;
break;
}
accum = accum * base + value;
nptr++;
}
if (sign == '-')
{
accum = (~accum) + 1;
}
}
}
/* Return the final pointer to the unused value */
if (endptr)
{
if (sign)
{
if (*(nptr - 1) == sign)
{
nptr--;
}
}
*endptr = (FAR char *)nptr;
}
return accum;
}
#endif