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incubator-nuttx/lib/lib_getopt.c

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/****************************************************************************
* lib_getopt.c
*
* Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 <sys/types.h>
#include <unistd.h>
#include <string.h>
/****************************************************************************
* Global Variables
****************************************************************************/
FAR char *optarg; /* Optional argument following option */
int optind = 1; /* Index into argv */
int optopt = '?'; /* unrecognized option character */
/****************************************************************************
* Private Variables
****************************************************************************/
static FAR char *g_optptr = NULL;
static boolean g_binitialized = FALSE;
/****************************************************************************
* Global Functions
****************************************************************************/
/****************************************************************************
* Name: Name
*
* Description: getopt() parses command-line arguments. Its arguments argc
* and argv are the argument count and array as passed to the main()
* function on program invocation. An element of argv that starts with
* '-' is an option element. The characters of this element (aside from
* the initial '-') are option characters. If getopt() is called repeatedly,
* it returns successively each of the option characters from each of the
* option elements.
*
* If getopt() finds another option character, it returns that character,
* updating the external variable optind and a static variable nextchar so
* that the next call to getopt() can resume the scan with the following
* option character or argv-element.
*
* If there are no more option characters, getopt() returns -1. Then optind
* is the index in argv of the first argv-element that is not an option.
*
* The 'optstring argument is a string containing the legitimate option
* characters. If such a character is followed by a colon, this indicates
* that the option requires an argument. If an argument is required for an
* option so getopt() places a pointer to the following text in the same
* argv-element, or the text of the following argv-element, in optarg.
*
* NOTES:
* 1. opterr is not supported and this implementation of getopt() never
* printfs error messages.
* 2. getopt is NOT threadsafe!
*
* Return: If an option was successfully found, then getopt() returns the
* option character. If all command-line options have been parsed, then
* getopt() returns -1. If getopt() encounters an option character that
* was not in optstring, then '?' is returned. If getopt() encounters an
* option with a missing argument, then the return value depends on the
* first character in optstring: if it is ':', then ':' is returned;
* otherwise '?' is returned.
*
****************************************************************************/
int getopt(int argc, FAR char *const argv[], FAR const char *optstring)
{
if (argv && optstring && argc > 1)
{
int noarg_ret = '?';
char *optchar;
/* The inital value of optind is 1. If getopt() is called again in the
* program, optind must be reset to some value <= 1.
*/
if (optind < 1 || !g_binitialized)
{
optind = 1; /* Skip over the program name */
g_optptr = NULL; /* Start at the beginning of the first argument */
g_binitialized = TRUE; /* Now we are initialized */
}
/* If the first character of opstring s ':', then ':' is in the event of
* a missing argument. Otherwise '?' is returned.
*/
if (*optstring == ':')
{
noarg_ret = ':';
optstring++;
}
/* Are we resuming in the middle, or at the end of a string of arguments?
* g_optptr == NULL means that we are started at the beginning of argv[optind];
* *g_optptr == means that we are starting at the beginning of optind+1
*/
while (!g_optptr || !*g_optptr)
{
/* We need to start at the beginning of the next argv. Check if we need
* to increment optind
*/
if (g_optptr)
{
/* Yes.. Increment it and check for the case where where we have
* processed everything in the argv[] array.
*/
optind++;
if (!argv[optind])
{
/* There are no more arguments, we are finished */
g_optptr = NULL;
g_binitialized = FALSE;
/* Return -1 with optind == all of the arguments */
return ERROR;
}
}
/* We are starting at the beginning of argv[optind]. In this case, the
* first character must be '-'
*/
g_optptr = argv[optind];
if (*g_optptr != '-')
{
/* The argument does not start with '-', we are finished */
g_optptr = NULL;
g_binitialized = FALSE;
/* Return the -1 with optind set to the non-option argument */
return ERROR;
}
/* Skip over the '-' */
g_optptr++;
}
/* Special case handling of "-" and "-:" */
if (!*g_optptr)
{
optopt = '\0'; /* We'll fix up g_optptr the next time we are called */
return '?';
}
/* Handle the case of "-:" */
if (*g_optptr == ':')
{
optopt = ':';
g_optptr++;
return '?';
}
/* g_optptr now points at the next option and it is not something crazy.
* check if the option is in the list of valid options.
*/
optchar = strchr(optstring, *g_optptr);
if (!optchar)
{
/* No this character is not in the list of valid options */
optopt = *g_optptr;
g_optptr++;
return '?';
}
/* Yes, the character is in the list of valid options. Does it have an
* required argument?
*/
if (optchar[1] != ':')
{
/* No, just return the character that we found */
g_optptr++;
return *optchar;
}
/* Yes. Is the required argument after the command in this same argument? */
if (g_optptr[1] != '\0')
{
/* Yes, return a pointer into the current argument */
optarg = &g_optptr[1];
optind++;
g_optptr = NULL;
return *optchar;
}
/* No.. is the optional argument the next argument in argv[] ? */
if (argv[optind+1] && *argv[optind+1] != '-')
{
/* Yes.. retun that */
optarg = argv[optind+1];
optind += 2;
g_optptr = NULL;
return *optchar;
}
/* No argument was supplied */
optarg = NULL;
optopt = *optchar;
optind++;
return noarg_ret;
}
optind = 1;
return ERROR;
}
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