incubator-nuttx/libc/string/lib_checkbase.c

116 lines
3.7 KiB
C

/****************************************************************************
* lib/string/lib_checkbase.c
*
* Copyright (C) 2007, 2009, 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <string.h>
#include <ctype.h>
#include "lib_internal.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lib_checkbase
*
* Description:
* This is part of the strol() family implementation. This function checks
* the initial part of a string to see if it can determine the numeric
* base that is represented.
*
* Assumptions:
* *ptr points to the first, non-whitespace character in the string.
*
****************************************************************************/
int lib_checkbase(int base, const char **pptr)
{
const char *ptr = *pptr;
/* Check for unspecified base */
if (!base)
{
/* Assume base 10 */
base = 10;
/* Check for leading '0' - that would signify octal or hex (or binary) */
if (*ptr == '0')
{
/* Assume octal */
base = 8;
ptr++;
/* Check for hexidecimal */
if ((*ptr == 'X' || *ptr == 'x') &&
lib_isbasedigit(ptr[1], 16, NULL))
{
base = 16;
ptr++;
}
}
}
/* If it a hexidecimal representation, than discard any leading "0X" or "0x" */
else if (base == 16)
{
if (ptr[0] == '0' && (ptr[1] == 'X' || ptr[1] == 'x'))
{
ptr += 2;
}
}
/* Return the updated pointer and base */
*pptr = ptr;
return base;
}