int getopt()

in c/tools/include/pncompat/internal/getopt.c [97:246]
107 lines of code
28 McCabe index (conditional complexity)

int getopt(int argc, char** argv, char* optstr)
{
	int c = 0;

	/* If we have new argv, reinitialize */
	if(prev_argv != argv || prev_argc != argc)
	{
		/* Initialize variables */
		prev_argv = argv;
		prev_argc = argc;
		argv_index = 1;
		argv_index2 = 1;
		opt_offset = 1;
		dashdash = 0;
		nonopt = 0;
	}

	/* Jump point in case we want to ignore the current argv_index */
	getopt_top:

	/* Misc. initializations */
	optarg = NULL;

	/* Dash-dash check */
	if(argv[argv_index] && !strcmp(argv[argv_index], "--"))
	{
		dashdash = 1;
		increment_index();
	}

	/* If we're at the end of argv, that's it. */
	if(argv[argv_index] == NULL)
	{
		c = -1;
	}
	/* Are we looking at a string? Single dash is also a string */
	else if(dashdash || argv[argv_index][0] != '-' || !strcmp(argv[argv_index], "-"))
	{
		/* If we want a string... */
		if(optstr[0] == '-')
		{
			c = 1;
			optarg = argv[argv_index];
			increment_index();
		}
		/* If we really don't want it (we're in POSIX mode), we're done */
		else if(optstr[0] == '+' || getenv("POSIXLY_CORRECT"))
		{
			c = -1;

			/* Everything else is a non-opt argument */
			nonopt = argc - argv_index;
		}
		/* If we mildly don't want it, then move it back */
		else
		{
			if(!permute_argv_once()) goto getopt_top;
			else c = -1;
		}
	}
	/* Otherwise we're looking at an option */
	else
	{
		char* opt_ptr = NULL;

		/* Grab the option */
		c = argv[argv_index][opt_offset++];

		/* Is the option in the optstr? */
		if(optstr[0] == '-') opt_ptr = strchr(optstr+1, c);
		else opt_ptr = strchr(optstr, c);
		/* Invalid argument */
		if(!opt_ptr)
		{
			if(opterr)
			{
				fprintf(stderr, "%s: invalid option -- %c\n", argv[0], c);
			}

			optopt = c;
			c = '?';

			/* Move onto the next option */
			increment_index();
		}
		/* Option takes argument */
		else if(opt_ptr[1] == ':')
		{
			/* ie, -oARGUMENT, -xxxoARGUMENT, etc. */
			if(argv[argv_index][opt_offset] != '\0')
			{
				optarg = &argv[argv_index][opt_offset];
				increment_index();
			}
			/* ie, -o ARGUMENT (only if it's a required argument) */
			else if(opt_ptr[2] != ':')
			{
				/* One of those "you're not expected to understand this" moment */
				if(argv_index2 < argv_index) argv_index2 = argv_index;
				while(argv[++argv_index2] && argv[argv_index2][0] == '-');
				optarg = argv[argv_index2];

				/* Don't cross into the non-option argument list */
				if(argv_index2 + nonopt >= prev_argc) optarg = NULL;

				/* Move onto the next option */
				increment_index();
			}
			else
			{
				/* Move onto the next option */
				increment_index();
			}

			/* In case we got no argument for an option with required argument */
			if(optarg == NULL && opt_ptr[2] != ':')
			{
				optopt = c;
				c = '?';

				if(opterr)
				{
					fprintf(stderr,"%s: option requires an argument -- %c\n",
							argv[0], optopt);
				}
			}
		}
		/* Option does not take argument */
		else
		{
			/* Next argv_index */
			if(argv[argv_index][opt_offset] == '\0')
			{
				increment_index();
			}
		}
	}

	/* Calculate optind */
	if(c == -1)
	{
		optind = argc - nonopt;
	}
	else
	{
		optind = argv_index;
	}

	return c;
}