407 lines
12 KiB
C
407 lines
12 KiB
C
/****************************************************************************
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getopt.c - Read command line options
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AUTHOR: Gregory Pietsch
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CREATED Fri Jan 10 21:13:05 1997
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DESCRIPTION:
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The getopt() function parses the command line arguments. Its arguments argc
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and argv are the argument count and array as passed to the main() function
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on program invocation. The argument optstring is a list of available option
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characters. If such a character is followed by a colon (`:'), the option
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takes an argument, which is placed in optarg. If such a character is
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followed by two colons, the option takes an optional argument, which is
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placed in optarg. If the option does not take an argument, optarg is NULL.
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The external variable optind is the index of the next array element of argv
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to be processed; it communicates from one call to the next which element to
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process.
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The getopt_long() function works like getopt() except that it also accepts
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long options started by two dashes `--'. If these take values, it is either
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in the form
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--arg=value
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or
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--arg value
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It takes the additional arguments longopts which is a pointer to the first
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element of an array of type struct option. The last element of the array
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has to be filled with NULL for the name field.
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The longind pointer points to the index of the current long option relative
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to longopts if it is non-NULL.
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The getopt() function returns the option character if the option was found
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successfully, `:' if there was a missing parameter for one of the options,
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`?' for an unknown option character, and EOF for the end of the option list.
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The getopt_long() function's return value is described in the header file.
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The function getopt_long_only() is identical to getopt_long(), except that a
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plus sign `+' can introduce long options as well as `--'.
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The following describes how to deal with options that follow non-option
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argv-elements.
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If the caller did not specify anything, the default is REQUIRE_ORDER if the
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environment variable POSIXLY_CORRECT is defined, PERMUTE otherwise.
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REQUIRE_ORDER means don't recognize them as options; stop option processing
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when the first non-option is seen. This is what Unix does. This mode of
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operation is selected by either setting the environment variable
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POSIXLY_CORRECT, or using `+' as the first character of the optstring
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parameter.
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PERMUTE is the default. We permute the contents of ARGV as we scan, so that
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eventually all the non-options are at the end. This allows options to be
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given in any order, even with programs that were not written to expect this.
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RETURN_IN_ORDER is an option available to programs that were written to
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expect options and other argv-elements in any order and that care about the
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ordering of the two. We describe each non-option argv-element as if it were
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the argument of an option with character code 1. Using `-' as the first
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character of the optstring parameter selects this mode of operation.
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The special argument `--' forces an end of option-scanning regardless of the
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value of ordering. In the case of RETURN_IN_ORDER, only `--' can cause
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getopt() and friends to return EOF with optind != argc.
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COPYRIGHT NOTICE AND DISCLAIMER:
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Copyright (C) 1997 Gregory Pietsch
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This file and the accompanying getopt.h header file are hereby placed in the
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public domain without restrictions. Just give the author credit, don't
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claim you wrote it or prevent anyone else from using it.
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Gregory Pietsch's current e-mail address:
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gpietsch@comcast.net
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****************************************************************************/
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/* include files */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <getopt.h>
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/* macros */
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/* types */
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typedef enum GETOPT_ORDERING_T
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{
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PERMUTE,
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RETURN_IN_ORDER,
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REQUIRE_ORDER
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} GETOPT_ORDERING_T;
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/* globally-defined variables */
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char *optarg = NULL;
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int optind = 0;
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int opterr = 1;
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int optopt = '?';
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/* functions */
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/* reverse_argv_elements: reverses num elements starting at argv */
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static void
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reverse_argv_elements (char ** argv, int num)
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{
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int i;
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char *tmp;
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for (i = 0; i < (num >> 1); i++)
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{
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tmp = argv[i];
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argv[i] = argv[num - i - 1];
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argv[num - i - 1] = tmp;
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}
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}
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/* permute: swap two blocks of argv-elements given their lengths */
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static void
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permute (char *const argv[], int len1, int len2)
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{
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reverse_argv_elements ((char **)argv, len1);
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reverse_argv_elements ((char **)argv, len1 + len2);
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reverse_argv_elements ((char **)argv, len2);
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}
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/* is_option: is this argv-element an option or the end of the option list? */
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static int
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is_option (char *argv_element, int only)
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{
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return ((argv_element == NULL)
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|| (argv_element[0] == '-') || (only && argv_element[0] == '+'));
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}
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/* getopt_internal: the function that does all the dirty work */
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static int
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getopt_internal (int argc, char *const argv[], const char *shortopts,
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const struct option *longopts, int *longind, int only)
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{
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GETOPT_ORDERING_T ordering = PERMUTE;
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static size_t optwhere = 0;
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size_t permute_from = 0;
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int num_nonopts = 0;
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int optindex = 0;
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size_t match_chars = 0;
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char *possible_arg = NULL;
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int longopt_match = -1;
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int has_arg = -1;
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char *cp;
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int arg_next = 0;
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/* first, deal with silly parameters and easy stuff */
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if (argc == 0 || argv == NULL || (shortopts == NULL && longopts == NULL))
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return EOF;
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if (optind >= argc || argv[optind] == NULL)
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return EOF;
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if (strcmp (argv[optind], "--") == 0)
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{
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optind++;
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return EOF;
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}
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/* if this is our first time through */
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if (optind == 0)
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optind = optwhere = 1;
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/* define ordering */
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if (shortopts != NULL && (*shortopts == '-' || *shortopts == '+'))
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{
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ordering = (*shortopts == '-') ? RETURN_IN_ORDER : REQUIRE_ORDER;
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shortopts++;
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}
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else
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ordering = (getenv ("POSIXLY_CORRECT") != NULL) ? REQUIRE_ORDER : PERMUTE;
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/*
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* based on ordering, find our next option, if we're at the beginning of
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* one
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*/
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if (optwhere == 1)
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{
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switch (ordering)
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{
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case PERMUTE:
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permute_from = optind;
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num_nonopts = 0;
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while (!is_option (argv[optind], only))
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{
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optind++;
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num_nonopts++;
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}
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if (argv[optind] == NULL)
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{
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/* no more options */
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optind = permute_from;
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return EOF;
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}
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else if (strcmp (argv[optind], "--") == 0)
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{
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/* no more options, but have to get `--' out of the way */
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permute (argv + permute_from, num_nonopts, 1);
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optind = permute_from + 1;
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return EOF;
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}
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break;
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case RETURN_IN_ORDER:
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if (!is_option (argv[optind], only))
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{
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optarg = argv[optind++];
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return (optopt = 1);
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}
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break;
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case REQUIRE_ORDER:
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if (!is_option (argv[optind], only))
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return EOF;
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break;
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}
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}
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/* we've got an option, so parse it */
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/* first, is it a long option? */
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if (longopts != NULL
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&& (memcmp (argv[optind], "--", 2) == 0
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|| (only && argv[optind][0] == '+')) && optwhere == 1)
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{
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/* handle long options */
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if (memcmp (argv[optind], "--", 2) == 0)
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optwhere = 2;
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longopt_match = -1;
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possible_arg = strchr (argv[optind] + optwhere, '=');
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if (possible_arg == NULL)
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{
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/* no =, so next argv might be arg */
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match_chars = strlen (argv[optind]);
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possible_arg = argv[optind] + match_chars;
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match_chars = match_chars - optwhere;
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}
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else
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match_chars = (possible_arg - argv[optind]) - optwhere;
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for (optindex = 0; longopts[optindex].name != NULL; optindex++)
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{
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if (memcmp (argv[optind] + optwhere,
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longopts[optindex].name, match_chars) == 0)
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{
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/* do we have an exact match? */
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if (match_chars == (int) (strlen (longopts[optindex].name)))
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{
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longopt_match = optindex;
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break;
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}
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/* do any characters match? */
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else
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{
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if (longopt_match < 0)
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longopt_match = optindex;
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else
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{
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/* we have ambiguous options */
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if (opterr)
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fprintf (stderr, "%s: option `%s' is ambiguous "
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"(could be `--%s' or `--%s')\n",
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argv[0],
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argv[optind],
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longopts[longopt_match].name,
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longopts[optindex].name);
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return (optopt = '?');
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}
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}
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}
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}
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if (longopt_match >= 0)
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has_arg = longopts[longopt_match].has_arg;
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}
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/* if we didn't find a long option, is it a short option? */
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if (longopt_match < 0 && shortopts != NULL)
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{
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cp = strchr (shortopts, argv[optind][optwhere]);
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if (cp == NULL)
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{
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/* couldn't find option in shortopts */
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if (opterr)
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fprintf (stderr,
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"%s: invalid option -- `-%c'\n",
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argv[0], argv[optind][optwhere]);
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optwhere++;
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if (argv[optind][optwhere] == '\0')
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{
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optind++;
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optwhere = 1;
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}
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return (optopt = '?');
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}
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has_arg = ((cp[1] == ':')
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? ((cp[2] == ':') ? OPTIONAL_ARG : REQUIRED_ARG) : NO_ARG);
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possible_arg = argv[optind] + optwhere + 1;
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optopt = *cp;
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}
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/* get argument and reset optwhere */
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arg_next = 0;
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switch (has_arg)
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{
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case OPTIONAL_ARG:
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if (*possible_arg == '=')
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possible_arg++;
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if (*possible_arg != '\0')
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{
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optarg = possible_arg;
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optwhere = 1;
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}
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else
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optarg = NULL;
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break;
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case REQUIRED_ARG:
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if (*possible_arg == '=')
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possible_arg++;
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if (*possible_arg != '\0')
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{
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optarg = possible_arg;
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optwhere = 1;
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}
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else if (optind + 1 >= argc)
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{
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if (opterr)
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{
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fprintf (stderr, "%s: argument required for option `", argv[0]);
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if (longopt_match >= 0)
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fprintf (stderr, "--%s'\n", longopts[longopt_match].name);
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else
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fprintf (stderr, "-%c'\n", *cp);
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}
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optind++;
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return (optopt = ':');
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}
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else
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{
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optarg = argv[optind + 1];
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arg_next = 1;
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optwhere = 1;
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}
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break;
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case NO_ARG:
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if (longopt_match < 0)
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{
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optwhere++;
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if (argv[optind][optwhere] == '\0')
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optwhere = 1;
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}
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else
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optwhere = 1;
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optarg = NULL;
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break;
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}
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/* do we have to permute or otherwise modify optind? */
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if (ordering == PERMUTE && optwhere == 1 && num_nonopts != 0)
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{
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permute (argv + permute_from, num_nonopts, 1 + arg_next);
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optind = permute_from + 1 + arg_next;
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}
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else if (optwhere == 1)
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optind = optind + 1 + arg_next;
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/* finally return */
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if (longopt_match >= 0)
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{
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if (longind != NULL)
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*longind = longopt_match;
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if (longopts[longopt_match].flag != NULL)
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{
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*(longopts[longopt_match].flag) = longopts[longopt_match].val;
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return 0;
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}
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else
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return longopts[longopt_match].val;
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}
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else
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return optopt;
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}
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int
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getopt (int argc, char *const argv[], const char *optstring)
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{
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return getopt_internal (argc, argv, optstring, NULL, NULL, 0);
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}
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int
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getopt_long (int argc, char *const argv[], const char *shortopts,
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const struct option *longopts, int *longind)
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{
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return getopt_internal (argc, argv, shortopts, longopts, longind, 0);
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}
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int
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getopt_long_only (int argc, char *const argv[], const char *shortopts,
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const struct option *longopts, int *longind)
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{
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return getopt_internal (argc, argv, shortopts, longopts, longind, 1);
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}
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/* end of file GETOPT.C */
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