nuttx/libs/libc/unistd/lib_getopt.c

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/****************************************************************************
* libs/libc/unistd/lib_getopt.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 <stdbool.h>
#include <getopt.h>
#include <string.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
FAR char *optarg; /* Optional argument following option */
int opterr = 0; /* Print error message */
int optind = 1; /* Index into argv */
int optopt = '?'; /* unrecognized option character */
/****************************************************************************
* Private Data
****************************************************************************/
static FAR char *g_optptr = NULL;
static FAR char * const *g_argv = NULL;
static int g_argc = 0;
static bool g_binitialized = false;
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: getopt
*
* 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!
* 3. This version of getopt() does not reset global variables until
* -1 is returned. As a result, your command line parsing loops
* must call getopt() repeatedly and continue to parse if other
* errors are returned ('?' or ':') until getopt() finally returns -1.
* (You can also set optind to -1 to force a reset).
*
* Returned Value:
* If an option was successfully found, then getopt() returns the option
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* 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)
{
/* Were new argc or argv passed in? This detects misuse of getopt() by
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* applications that break out of the getopt() loop before getop() returns
* -1.
*/
if (argc != g_argc || argv != g_argv)
{
/* Yes, clear the internal state */
g_binitialized = false;
g_argc = argc;
g_argv = argv;
}
/* Verify input parameters. */
if (argv != NULL && optstring != NULL)
{
FAR char *optchar;
int noarg_ret = '?';
/* The initial 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)
{
optarg = NULL;
optind = 1; /* Skip over the program name */
optopt = '?';
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 == \0 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++;
}
/* Check for the end of the argument list */
g_optptr = argv[optind];
if (!g_optptr)
{
/* There are no more arguments, we are finished */
g_binitialized = false;
return ERROR;
}
/* We are starting at the beginning of argv[optind]. In this case,
* the first character must be '-'
*/
if (*g_optptr != '-')
{
/* The argument does not start with '-', we are finished */
g_binitialized = false;
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, no arguments. Just return the character that we found */
g_optptr++;
return *optchar;
}
/* Yes, it has a required argument. Is the required argument
* immediately 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.. return that */
optarg = argv[optind + 1];
optind += 2;
g_optptr = NULL;
return *optchar;
}
/* No argument was supplied */
g_optptr = NULL;
optarg = NULL;
optopt = *optchar;
optind++;
return noarg_ret;
}
/* Restore the initial, uninitialized state */
g_binitialized = false;
return ERROR;
}
int getopt_long(int argc, FAR char *const argv[],
FAR const char *shortopts,
FAR const struct option *longopts,
FAR int *longind)
{
return getopt(argc, argv, shortopts);
}