143 lines
4.3 KiB
C
143 lines
4.3 KiB
C
/****************************************************************************
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* /libs/libc/stdlib/lib_strtoul.c
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*
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* Copyright (C) 2007, 2009, 2011, 2016-2017, 2019 Gregory Nutt.
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* All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdlib.h>
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#include <errno.h>
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#include "libc.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: strtoul
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*
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* Description:
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* The strtoul() function converts the initial part of the string in
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* nptr to a long unsigned integer value according to the given base, which
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* must be between 2 and 36 inclusive, or be the special value 0.
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*
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* Returned Value:
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* - The converted value, if the base and number are valid
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* - 0 if an error occurs, and set errno to:
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* * EINVAL if base < 2 or base > 36
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* - ULONG_MAX if an overflow occurs, and set errno to:
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* * ERANGE if the number cannot be represented using unsigned long
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*
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****************************************************************************/
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unsigned long strtoul(FAR const char *nptr, FAR char **endptr, int base)
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{
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unsigned long accum = 0;
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unsigned long prev;
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int value;
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char sign = 0;
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if (nptr)
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{
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/* Skip leading spaces */
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lib_skipspace(&nptr);
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/* Check for leading + or - already done for strtol */
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if (*nptr == '-' || *nptr == '+')
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{
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sign = *nptr;
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nptr++;
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}
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/* Check for unspecified or incorrect base */
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base = lib_checkbase(base, &nptr);
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if (base < 0)
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{
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set_errno(EINVAL);
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accum = 0;
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}
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else
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{
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/* Accumulate each "digit" */
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while (lib_isbasedigit(*nptr, base, &value))
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{
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prev = accum;
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accum = accum * base + value;
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nptr++;
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/* Check for overflow */
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if (accum < prev)
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{
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set_errno(ERANGE);
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accum = ULONG_MAX;
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break;
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}
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}
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if (sign == '-')
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{
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accum = (~accum) + 1;
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}
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}
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}
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/* Return the final pointer to the unused value */
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if (endptr)
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{
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if (sign)
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{
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if (*(nptr - 1) == sign)
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{
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nptr--;
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}
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}
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*endptr = (FAR char *)nptr;
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}
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return accum;
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}
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