/****************************************************************************
* lib/string/lib_strtokr.c
*
* Copyright (C) 2007, 2008, 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
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <string.h>
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: strtok_r
*
* Description:
* The strtok_r() function is a reentrant version strtok().
* Like strtok(), it parses a string into a sequence of
* tokens. On the first call to strtok() the string to be
* parsed should be specified in 'str'. In each subsequent
* call that should parse the same string, 'str' should be
* NULL.
*
* The 'saveptr' argument is a pointer to a char *
* variable that is used internally by strtok_r() in
* order to maintain context between successive calls
* that parse the same string.
*
* On the first call to strtok_r(), 'str' should point to the
* string to be parsed, and the value of 'saveptr' is
* ignored. In subsequent calls, 'str' should be NULL, and
* saveptr should be unchanged since the previous call.
*
* The 'delim' argument specifies a set of characters that
* delimit the tokens in the parsed string. The caller
* may specify different strings in delim in successive
* calls that parse the same string.
*
* Each call to strtok_r() returns a pointer to a null-
* terminated string containing the next token. This
* string does not include the delimiting character. If
* no more tokens are found, strtok_r() returns NULL.
*
* A sequence of two or more contiguous delimiter
* characters in the parsed string is considered to be a
* single delimiter. Delimiter characters at the start or
* end of the string are ignored. The tokens returned by
* strtok() are always non-empty strings.
*
* Return
* strtok_r() returns a pointer to the next token, or NULL
* if there are no more tokens.
*
****************************************************************************/
FAR char *strtok_r(FAR char *str, FAR const char *delim, FAR char **saveptr)
{
char *pbegin;
char *pend = NULL;
/* Decide if we are starting a new string or continuing from
* the point we left off.
*/
if (str)
{
pbegin = str;
}
else if (saveptr && *saveptr)
{
pbegin = *saveptr;
}
else
{
return NULL;
}
/* Find the beginning of the next token */
for (;
*pbegin && strchr(delim, *pbegin) != NULL;
pbegin++);
/* If we are at the end of the string with nothing
* but delimiters found, then return NULL.
*/
if (!*pbegin)
{
return NULL;
}
/* Find the end of the token */
for (pend = pbegin + 1;
*pend && strchr(delim, *pend) == NULL;
pend++);
/* pend either points to the end of the string or to
* the first delimiter after the string.
*/
if (*pend)
{
/* Turn the delimiter into a null terminator */
*pend++ = '\0';
}
/* Save the pointer where we left off and return the
* beginning of the token.
*/
if (saveptr)
{
*saveptr = pend;
}
return pbegin;
}
