text: #include <linux/compiler.h>
  #include <linux/string.h>
  #include <linux/types.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <stdint.h>
  #include <string.h>
  #include <ctype.h>
  #include "subcmd-util.h"
  #include "parse-options.h"
  #include "subcmd-config.h"
  #include "pager.h"
  
  #define OPT_SHORT 1
  #define OPT_UNSET 2
  
  char *error_buf;
  
  static int opterror(const struct option *opt, const char *reason, int flags)
  {
  	if (flags & OPT_SHORT)
  		fprintf(stderr, " Error: switch `%c' %s", opt->short_name, reason);
  	else if (flags & OPT_UNSET)
  		fprintf(stderr, " Error: option `no-%s' %s", opt->long_name, reason);
  	else
  		fprintf(stderr, " Error: option `%s' %s", opt->long_name, reason);
  
  	return -1;
  }
  
  static const char *skip_prefix(const char *str, const char *prefix)
  {
  	size_t len = strlen(prefix);
  	return strncmp(str, prefix, len) ? NULL : str + len;
  }
  
  static void optwarning(const struct option *opt, const char *reason, int flags)
  {
  	if (flags & OPT_SHORT)
  		fprintf(stderr, " Warning: switch `%c' %s", opt->short_name, reason);
  	else if (flags & OPT_UNSET)
  		fprintf(stderr, " Warning: option `no-%s' %s", opt->long_name, reason);
  	else
  		fprintf(stderr, " Warning: option `%s' %s", opt->long_name, reason);
  }
  
  static int get_arg(struct parse_opt_ctx_t *p, const struct option *opt,
  		   int flags, const char **arg)
  {
  	const char *res;
  
  	if (p->opt) {
  		res = p->opt;
  		p->opt = NULL;
  	} else if ((opt->flags & PARSE_OPT_LASTARG_DEFAULT) && (p->argc == 1 ||
  		    **(p->argv + 1) == '-')) {
  		res = (const char *)opt->defval;
  	} else if (p->argc > 1) {
  		p->argc--;
  		res = *++p->argv;
  	} else
  		return opterror(opt, "requires a value", flags);
  	if (arg)
  		*arg = res;
  	return 0;
  }
  
  static int get_value(struct parse_opt_ctx_t *p,
  		     const struct option *opt, int flags)
  {
  	const char *s, *arg = NULL;
  	const int unset = flags & OPT_UNSET;
  	int err;
  
  	if (unset && p->opt)
  		return opterror(opt, "takes no value", flags);
  	if (unset && (opt->flags & PARSE_OPT_NONEG))
  		return opterror(opt, "isn't available", flags);
  	if (opt->flags & PARSE_OPT_DISABLED)
  		return opterror(opt, "is not usable", flags);
  
  	if (opt->flags & PARSE_OPT_EXCLUSIVE) {
  		if (p->excl_opt && p->excl_opt != opt) {
  			char msg[128];
  
  			if (((flags & OPT_SHORT) && p->excl_opt->short_name) ||
  			    p->excl_opt->long_name == NULL) {
  				snprintf(msg, sizeof(msg), "cannot be used with switch `%c'",
  					 p->excl_opt->short_name);
  			} else {
  				snprintf(msg, sizeof(msg), "cannot be used with %s",
  					 p->excl_opt->long_name);
  			}
  			opterror(opt, msg, flags);
  			return -3;
  		}
  		p->excl_opt = opt;
  	}
  	if (!(flags & OPT_SHORT) && p->opt) {
  		switch (opt->type) {
  		case OPTION_CALLBACK:
  			if (!(opt->flags & PARSE_OPT_NOARG))
  				break;
  			/* FALLTHROUGH */
  		case OPTION_BOOLEAN:
  		case OPTION_INCR:
  		case OPTION_BIT:
  		case OPTION_SET_UINT:
  		case OPTION_SET_PTR:
  			return opterror(opt, "takes no value", flags);
  		case OPTION_END:
  		case OPTION_ARGUMENT:
  		case OPTION_GROUP:
  		case OPTION_STRING:
  		case OPTION_INTEGER:
  		case OPTION_UINTEGER:
  		case OPTION_LONG:
  		case OPTION_U64:
  		default:
  			break;
  		}
  	}
  
  	if (opt->flags & PARSE_OPT_NOBUILD) {
  		char reason[128];
  		bool noarg = false;
  
  		err = snprintf(reason, sizeof(reason),
  				opt->flags & PARSE_OPT_CANSKIP ?
  					"is being ignored because %s " :
  					"is not available because %s",
  				opt->build_opt);
  		reason[sizeof(reason) - 1] = '\0';
  
  		if (err < 0)
  			strncpy(reason, opt->flags & PARSE_OPT_CANSKIP ?
  					"is being ignored" :
  					"is not available",
  					sizeof(reason));
  
  		if (!(opt->flags & PARSE_OPT_CANSKIP))
  			return opterror(opt, reason, flags);
  
  		err = 0;
  		if (unset)
  			noarg = true;
  		if (opt->flags & PARSE_OPT_NOARG)
  			noarg = true;
  		if (opt->flags & PARSE_OPT_OPTARG && !p->opt)
  			noarg = true;
  
  		switch (opt->type) {
  		case OPTION_BOOLEAN:
  		case OPTION_INCR:
  		case OPTION_BIT:
  		case OPTION_SET_UINT:
  		case OPTION_SET_PTR:
  		case OPTION_END:
  		case OPTION_ARGUMENT:
  		case OPTION_GROUP:
  			noarg = true;
  			break;
  		case OPTION_CALLBACK:
  		case OPTION_STRING:
  		case OPTION_INTEGER:
  		case OPTION_UINTEGER:
  		case OPTION_LONG:
  		case OPTION_U64:
  		default:
  			break;
  		}
  
  		if (!noarg)
  			err = get_arg(p, opt, flags, NULL);
  		if (err)
  			return err;
  
  		optwarning(opt, reason, flags);
  		return 0;
  	}
  
  	switch (opt->type) {
  	case OPTION_BIT:
  		if (unset)
  			*(int *)opt->value &= ~opt->defval;
  		else
  			*(int *)opt->value |= opt->defval;
  		return 0;
  
  	case OPTION_BOOLEAN:
  		*(bool *)opt->value = unset ? false : true;
  		if (opt->set)
  			*(bool *)opt->set = true;
  		return 0;
  
  	case OPTION_INCR:
  		*(int *)opt->value = unset ? 0 : *(int *)opt->value + 1;
  		return 0;
  
  	case OPTION_SET_UINT:
  		*(unsigned int *)opt->value = unset ? 0 : opt->defval;
  		return 0;
  
  	case OPTION_SET_PTR:
  		*(void **)opt->value = unset ? NULL : (void *)opt->defval;
  		return 0;
  
  	case OPTION_STRING:
  		err = 0;
  		if (unset)
  			*(const char **)opt->value = NULL;
  		else if (opt->flags & PARSE_OPT_OPTARG && !p->opt)
  			*(const char **)opt->value = (const char *)opt->defval;
  		else
  			err = get_arg(p, opt, flags, (const char **)opt->value);
  
  		if (opt->set)
  			*(bool *)opt->set = true;
  
  		/* PARSE_OPT_NOEMPTY: Allow NULL but disallow empty string. */
  		if (opt->flags & PARSE_OPT_NOEMPTY) {
  			const char *val = *(const char **)opt->value;
  
  			if (!val)
  				return err;
  
  			/* Similar to unset if we are given an empty string. */
  			if (val[0] == '\0') {
  				*(const char **)opt->value = NULL;
  				return 0;
  			}
  		}
  
  		return err;
  
  	case OPTION_CALLBACK:
  		if (unset)
  			return (*opt->callback)(opt, NULL, 1) ? (-1) : 0;
  		if (opt->flags & PARSE_OPT_NOARG)
  			return (*opt->callback)(opt, NULL, 0) ? (-1) : 0;
  		if (opt->flags & PARSE_OPT_OPTARG && !p->opt)
  			return (*opt->callback)(opt, NULL, 0) ? (-1) : 0;
  		if (get_arg(p, opt, flags, &arg))
  			return -1;
  		return (*opt->callback)(opt, arg, 0) ? (-1) : 0;
  
  	case OPTION_INTEGER:
  		if (unset) {
  			*(int *)opt->value = 0;
  			return 0;
  		}
  		if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
  			*(int *)opt->value = opt->defval;
  			return 0;
  		}
  		if (get_arg(p, opt, flags, &arg))
  			return -1;
  		*(int *)opt->value = strtol(arg, (char **)&s, 10);
  		if (*s)
  			return opterror(opt, "expects a numerical value", flags);
  		return 0;
  
  	case OPTION_UINTEGER:
  		if (unset) {
  			*(unsigned int *)opt->value = 0;
  			return 0;
  		}
  		if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
  			*(unsigned int *)opt->value = opt->defval;
  			return 0;
  		}
  		if (get_arg(p, opt, flags, &arg))
  			return -1;
  		if (arg[0] == '-')
  			return opterror(opt, "expects an unsigned numerical value", flags);
  		*(unsigned int *)opt->value = strtol(arg, (char **)&s, 10);
  		if (*s)
  			return opterror(opt, "expects a numerical value", flags);
  		return 0;
  
  	case OPTION_LONG:
  		if (unset) {
  			*(long *)opt->value = 0;
  			return 0;
  		}
  		if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
  			*(long *)opt->value = opt->defval;
  			return 0;
  		}
  		if (get_arg(p, opt, flags, &arg))
  			return -1;
  		*(long *)opt->value = strtol(arg, (char **)&s, 10);
  		if (*s)
  			return opterror(opt, "expects a numerical value", flags);
  		return 0;
  
  	case OPTION_U64:
  		if (unset) {
  			*(u64 *)opt->value = 0;
  			return 0;
  		}
  		if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
  			*(u64 *)opt->value = opt->defval;
  			return 0;
  		}
  		if (get_arg(p, opt, flags, &arg))
  			return -1;
  		if (arg[0] == '-')
  			return opterror(opt, "expects an unsigned numerical value", flags);
  		*(u64 *)opt->value = strtoull(arg, (char **)&s, 10);
  		if (*s)
  			return opterror(opt, "expects a numerical value", flags);
  		return 0;
  
  	case OPTION_END:
  	case OPTION_ARGUMENT:
  	case OPTION_GROUP:
  	default:
  		die("should not happen, someone must be hit on the forehead");
  	}
  }
  
  static int parse_short_opt(struct parse_opt_ctx_t *p, const struct option *options)
  {
  retry:
  	for (; options->type != OPTION_END; options++) {
  		if (options->short_name == *p->opt) {
  			p->opt = p->opt[1] ? p->opt + 1 : NULL;
  			return get_value(p, options, OPT_SHORT);
  		}
  	}
  
  	if (options->parent) {
  		options = options->parent;
  		goto retry;
  	}
  
  	return -2;
  }
  
  static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
                            const struct option *options)
  {
  	const char *arg_end = strchr(arg, '=');
  	const struct option *abbrev_option = NULL, *ambiguous_option = NULL;
  	int abbrev_flags = 0, ambiguous_flags = 0;
  
  	if (!arg_end)
  		arg_end = arg + strlen(arg);
  
  retry:
  	for (; options->type != OPTION_END; options++) {
  		const char *rest;
  		int flags = 0;
  
  		if (!options->long_name)
  			continue;
  
  		rest = skip_prefix(arg, options->long_name);
  		if (options->type == OPTION_ARGUMENT) {
  			if (!rest)
  				continue;
  			if (*rest == '=')
  				return opterror(options, "takes no value", flags);
  			if (*rest)
  				continue;
  			p->out[p->cpidx++] = arg - 2;
  			return 0;
  		}
  		if (!rest) {
  			if (!prefixcmp(options->long_name, "no-")) {
  				/*
  				 * The long name itself starts with "no-", so
  				 * accept the option without "no-" so that users
  				 * do not have to enter "no-no-" to get the
  				 * negation.
  				 */
  				rest = skip_prefix(arg, options->long_name + 3);
  				if (rest) {
  					flags |= OPT_UNSET;
  					goto match;
  				}
  				/* Abbreviated case */
  				if (!prefixcmp(options->long_name + 3, arg)) {
  					flags |= OPT_UNSET;
  					goto is_abbreviated;
  				}
  			}
  			/* abbreviated? */
  			if (!strncmp(options->long_name, arg, arg_end - arg)) {
  is_abbreviated:
  				if (abbrev_option) {
  					/*
  					 * If this is abbreviated, it is
  					 * ambiguous. So when there is no
  					 * exact match later, we need to
  					 * error out.
  					 */
  					ambiguous_option = abbrev_option;
  					ambiguous_flags = abbrev_flags;
  				}
  				if (!(flags & OPT_UNSET) && *arg_end)
  					p->opt = arg_end + 1;
  				abbrev_option = options;
  				abbrev_flags = flags;
  				continue;
  			}
  			/* negated and abbreviated very much? */
  			if (!prefixcmp("no-", arg)) {
  				flags |= OPT_UNSET;
  				goto is_abbreviated;
  			}
  			/* negated? */
  			if (strncmp(arg, "no-", 3))
  				continue;
  			flags |= OPT_UNSET;
  			rest = skip_prefix(arg + 3, options->long_name);
  			/* abbreviated and negated? */
  			if (!rest && !prefixcmp(options->long_name, arg + 3))
  				goto is_abbreviated;
  			if (!rest)
  				continue;
  		}
  match:
  		if (*rest) {
  			if (*rest != '=')
  				continue;
  			p->opt = rest + 1;
  		}
  		return get_value(p, options, flags);
  	}
  
  	if (ambiguous_option) {
  		 fprintf(stderr,
  			 " Error: Ambiguous option: %s (could be --%s%s or --%s%s)",
  			 arg,
  			 (ambiguous_flags & OPT_UNSET) ?  "no-" : "",
  			 ambiguous_option->long_name,
  			 (abbrev_flags & OPT_UNSET) ?  "no-" : "",
  			 abbrev_option->long_name);
  		 return -1;
  	}
  	if (abbrev_option)
  		return get_value(p, abbrev_option, abbrev_flags);
  
  	if (options->parent) {
  		options = options->parent;
  		goto retry;
  	}
  
  	return -2;
  }
  
  static void check_typos(const char *arg, const struct option *options)
  {
  	if (strlen(arg) < 3)
  		return;
  
  	if (!prefixcmp(arg, "no-")) {
  		fprintf(stderr, " Error: did you mean `--%s` (with two dashes ?)", arg);
  		exit(129);
  	}
  
  	for (; options->type != OPTION_END; options++) {
  		if (!options->long_name)
  			continue;
  		if (!prefixcmp(options->long_name, arg)) {
  			fprintf(stderr, " Error: did you mean `--%s` (with two dashes ?)", arg);
  			exit(129);
  		}
  	}
  }
  
  static void parse_options_start(struct parse_opt_ctx_t *ctx,
  				int argc, const char **argv, int flags)
  {
  	memset(ctx, 0, sizeof(*ctx));
  	ctx->argc = argc - 1;
  	ctx->argv = argv + 1;
  	ctx->out  = argv;
  	ctx->cpidx = ((flags & PARSE_OPT_KEEP_ARGV0) != 0);
  	ctx->flags = flags;
  	if ((flags & PARSE_OPT_KEEP_UNKNOWN) &&
  	    (flags & PARSE_OPT_STOP_AT_NON_OPTION))
  		die("STOP_AT_NON_OPTION and KEEP_UNKNOWN don't go together");
  }
  
  static int usage_with_options_internal(const char * const *,
  				       const struct option *, int,
  				       struct parse_opt_ctx_t *);
  
  static int parse_options_step(struct parse_opt_ctx_t *ctx,
  			      const struct option *options,
  			      const char * const usagestr[])
  {
  	int internal_help = !(ctx->flags & PARSE_OPT_NO_INTERNAL_HELP);
  	int excl_short_opt = 1;
  	const char *arg;
  
  	/* we must reset ->opt, unknown short option leave it dangling */
  	ctx->opt = NULL;
  
  	for (; ctx->argc; ctx->argc--, ctx->argv++) {
  		arg = ctx->argv[0];
  		if (*arg != '-' || !arg[1]) {
  			if (ctx->flags & PARSE_OPT_STOP_AT_NON_OPTION)
  				break;
  			ctx->out[ctx->cpidx++] = ctx->argv[0];
  			continue;
  		}
  
  		if (arg[1] != '-') {
  			ctx->opt = ++arg;
  			if (internal_help && *ctx->opt == 'h') {
  				return usage_with_options_internal(usagestr, options, 0, ctx);
  			}
  			switch (parse_short_opt(ctx, options)) {
  			case -1:
  				return parse_options_usage(usagestr, options, arg, 1);
  			case -2:
  				goto unknown;
  			case -3:
  				goto exclusive;
  			default:
  				break;
  			}
  			if (ctx->opt)
  				check_typos(arg, options);
  			while (ctx->opt) {
  				if (internal_help && *ctx->opt == 'h')
  					return usage_with_options_internal(usagestr, options, 0, ctx);
  				arg = ctx->opt;
  				switch (parse_short_opt(ctx, options)) {
  				case -1:
  					return parse_options_usage(usagestr, options, arg, 1);
  				case -2:
  					/* fake a short option thing to hide the fact that we may have
  					 * started to parse aggregated stuff
  					 *
  					 * This is leaky, too bad.
  					 */
  					ctx->argv[0] = strdup(ctx->opt - 1);
  					*(char *)ctx->argv[0] = '-';
  					goto unknown;
  				case -3:
  					goto exclusive;
  				default:
  					break;
  				}
  			}
  			continue;
  		}
  
  		if (!arg[2]) { /* "--" */
  			if (!(ctx->flags & PARSE_OPT_KEEP_DASHDASH)) {
  				ctx->argc--;
  				ctx->argv++;
  			}
  			break;
  		}
  
  		arg += 2;
  		if (internal_help && !strcmp(arg, "help-all"))
  			return usage_with_options_internal(usagestr, options, 1, ctx);
  		if (internal_help && !strcmp(arg, "help"))
  			return usage_with_options_internal(usagestr, options, 0, ctx);
  		if (!strcmp(arg, "list-opts"))
  			return PARSE_OPT_LIST_OPTS;
  		if (!strcmp(arg, "list-cmds"))
  			return PARSE_OPT_LIST_SUBCMDS;
  		switch (parse_long_opt(ctx, arg, options)) {
  		case -1:
  			return parse_options_usage(usagestr, options, arg, 0);
  		case -2:
  			goto unknown;
  		case -3:
  			excl_short_opt = 0;
  			goto exclusive;
  		default:
  			break;
  		}
  		continue;
  unknown:
  		if (!(ctx->flags & PARSE_OPT_KEEP_UNKNOWN))
  			return PARSE_OPT_UNKNOWN;
  		ctx->out[ctx->cpidx++] = ctx->argv[0];
  		ctx->opt = NULL;
  	}
  	return PARSE_OPT_DONE;
  
  exclusive:
  	parse_options_usage(usagestr, options, arg, excl_short_opt);
  	if ((excl_short_opt && ctx->excl_opt->short_name) ||
  	    ctx->excl_opt->long_name == NULL) {
  		char opt = ctx->excl_opt->short_name;
  		parse_options_usage(NULL, options, &opt, 1);
  	} else {
  		parse_options_usage(NULL, options, ctx->excl_opt->long_name, 0);
  	}
  	return PARSE_OPT_HELP;
  }
  
  static int parse_options_end(struct parse_opt_ctx_t *ctx)
  {
  	memmove(ctx->out + ctx->cpidx, ctx->argv, ctx->argc * sizeof(*ctx->out));
  	ctx->out[ctx->cpidx + ctx->argc] = NULL;
  	return ctx->cpidx + ctx->argc;
  }
  
  int parse_options_subcommand(int argc, const char **argv, const struct option *options,
  			const char *const subcommands[], const char *usagestr[], int flags)
  {
  	struct parse_opt_ctx_t ctx;
  
  	/* build usage string if it's not provided */
  	if (subcommands && !usagestr[0]) {
  		char *buf = NULL;
  
  		astrcatf(&buf, "%s %s [<options>] {", subcmd_config.exec_name, argv[0]);
  
  		for (int i = 0; subcommands[i]; i++) {
  			if (i)
  				astrcat(&buf, "|");
  			astrcat(&buf, subcommands[i]);
  		}
  		astrcat(&buf, "}");
  
  		usagestr[0] = buf;
  	}
  
  	parse_options_start(&ctx, argc, argv, flags);
  	switch (parse_options_step(&ctx, options, usagestr)) {
  	case PARSE_OPT_HELP:
  		exit(129);
  	case PARSE_OPT_DONE:
  		break;
  	case PARSE_OPT_LIST_OPTS:
  		while (options->type != OPTION_END) {
  			if (options->long_name)
  				printf("--%s ", options->long_name);
  			options++;
  		}
  		putchar('\n');
  		exit(130);
  	case PARSE_OPT_LIST_SUBCMDS:
  		if (subcommands) {
  			for (int i = 0; subcommands[i]; i++)
  				printf("%s ", subcommands[i]);
  		}
  		putchar('\n');
  		exit(130);
  	default: /* PARSE_OPT_UNKNOWN */
  		if (ctx.argv[0][1] == '-')
  			astrcatf(&error_buf, "unknown option `%s'",
  				 ctx.argv[0] + 2);
  		else
  			astrcatf(&error_buf, "unknown switch `%c'", *ctx.opt);
  		usage_with_options(usagestr, options);
  	}
  
  	return parse_options_end(&ctx);
  }
  
  int parse_options(int argc, const char **argv, const struct option *options,
  		  const char * const usagestr[], int flags)
  {
  	return parse_options_subcommand(argc, argv, options, NULL,
  					(const char **) usagestr, flags);
  }
  
  #define USAGE_OPTS_WIDTH 24
  #define USAGE_GAP         2
  
  static void print_option_help(const struct option *opts, int full)
  {
  	size_t pos;
  	int pad;
  
  	if (opts->type == OPTION_GROUP) {
  		fputc('\n', stderr);
  		if (*opts->help)
  			fprintf(stderr, "%s\n", opts->help);
  		return;
  	}
  	if (!full && (opts->flags & PARSE_OPT_HIDDEN))
  		return;
  	if (opts->flags & PARSE_OPT_DISABLED)
  		return;
  
  	pos = fprintf(stderr, "    ");
  	if (opts->short_name)
  		pos += fprintf(stderr, "-%c", opts->short_name);
  	else
  		pos += fprintf(stderr, "    ");
  
  	if (opts->long_name && opts->short_name)
  		pos += fprintf(stderr, ", ");
  	if (opts->long_name)
  		pos += fprintf(stderr, "--%s", opts->long_name);
  
  	switch (opts->type) {
  	case OPTION_ARGUMENT:
  		break;
  	case OPTION_LONG:
  	case OPTION_U64:
  	case OPTION_INTEGER:
  	case OPTION_UINTEGER:
  		if (opts->flags & PARSE_OPT_OPTARG)
  			if (opts->long_name)
  				pos += fprintf(stderr, "[=<n>]");
  			else
  				pos += fprintf(stderr, "[<n>]");
  		else
  			pos += fprintf(stderr, " <n>");
  		break;
  	case OPTION_CALLBACK:
  		if (opts->flags & PARSE_OPT_NOARG)
  			break;
  		/* FALLTHROUGH */
  	case OPTION_STRING:
  		if (opts->argh) {
  			if (opts->flags & PARSE_OPT_OPTARG)
  				if (opts->long_name)
  					pos += fprintf(stderr, "[=<%s>]", opts->argh);
  				else
  					pos += fprintf(stderr, "[<%s>]", opts->argh);
  			else
  				pos += fprintf(stderr, " <%s>", opts->argh);
  		} else {
  			if (opts->flags & PARSE_OPT_OPTARG)
  				if (opts->long_name)
  					pos += fprintf(stderr, "[=...]");
  				else
  					pos += fprintf(stderr, "[...]");
  			else
  				pos += fprintf(stderr, " ...");
  		}
  		break;
  	default: /* OPTION_{BIT,BOOLEAN,SET_UINT,SET_PTR} */
  	case OPTION_END:
  	case OPTION_GROUP:
  	case OPTION_BIT:
  	case OPTION_BOOLEAN:
  	case OPTION_INCR:
  	case OPTION_SET_UINT:
  	case OPTION_SET_PTR:
  		break;
  	}
  
  	if (pos <= USAGE_OPTS_WIDTH)
  		pad = USAGE_OPTS_WIDTH - pos;
  	else {
  		fputc('\n', stderr);
  		pad = USAGE_OPTS_WIDTH;
  	}
  	fprintf(stderr, "%*s%s\n", pad + USAGE_GAP, "", opts->help);
  	if (opts->flags & PARSE_OPT_NOBUILD)
  		fprintf(stderr, "%*s(not built-in because %s)\n",
  			USAGE_OPTS_WIDTH + USAGE_GAP, "",
  			opts->build_opt);
  }
  
  static int option__cmp(const void *va, const void *vb)
  {
  	const struct option *a = va, *b = vb;
  	int sa = tolower(a->short_name), sb = tolower(b->short_name), ret;
  
  	if (sa == 0)
  		sa = 'z' + 1;
  	if (sb == 0)
  		sb = 'z' + 1;
  
  	ret = sa - sb;
  
  	if (ret == 0) {
  		const char *la = a->long_name ?: "",
  			   *lb = b->long_name ?: "";
  		ret = strcmp(la, lb);
  	}
  
  	return ret;
  }
  
  static struct option *options__order(const struct option *opts)
  {
  	int nr_opts = 0, len;
  	const struct option *o = opts;
  	struct option *ordered;
  
  	for (o = opts; o->type != OPTION_END; o++)
  		++nr_opts;
  
  	len = sizeof(*o) * (nr_opts + 1);
  	ordered = malloc(len);
  	if (!ordered)
  		goto out;
  	memcpy(ordered, opts, len);
  
  	qsort(ordered, nr_opts, sizeof(*o), option__cmp);
  out:
  	return ordered;
  }
  
  static bool option__in_argv(const struct option *opt, const struct parse_opt_ctx_t *ctx)
  {
  	int i;
  
  	for (i = 1; i < ctx->argc; ++i) {
  		const char *arg = ctx->argv[i];
  
  		if (arg[0] != '-') {
  			if (arg[1] == '\0') {
  				if (arg[0] == opt->short_name)
  					return true;
  				continue;
  			}
  
  			if (opt->long_name && strcmp(opt->long_name, arg) == 0)
  				return true;
  
  			if (opt->help && strcasestr(opt->help, arg) != NULL)
  				return true;
  
  			continue;
  		}
  
  		if (arg[1] == opt->short_name ||
  		    (arg[1] == '-' && opt->long_name && strcmp(opt->long_name, arg + 2) == 0))
  			return true;
  	}
  
  	return false;
  }
  
  static int usage_with_options_internal(const char * const *usagestr,
  				       const struct option *opts, int full,
  				       struct parse_opt_ctx_t *ctx)
  {
  	struct option *ordered;
  
  	if (!usagestr)
  		return PARSE_OPT_HELP;
  
  	setup_pager();
  
  	if (error_buf) {
  		fprintf(stderr, "  Error: %s\n", error_buf);
  		zfree(&error_buf);
  	}
  
  	fprintf(stderr, "\n Usage: %s\n", *usagestr++);
  	while (*usagestr && **usagestr)
  		fprintf(stderr, "    or: %s\n", *usagestr++);
  	while (*usagestr) {
  		fprintf(stderr, "%s%s\n",
  				**usagestr ? "    " : "",
  				*usagestr);
  		usagestr++;
  	}
  
  	if (opts->type != OPTION_GROUP)
  		fputc('\n', stderr);
  
  	ordered = options__order(opts);
  	if (ordered)
  		opts = ordered;
  
  	for (  ; opts->type != OPTION_END; opts++) {
  		if (ctx && ctx->argc > 1 && !option__in_argv(opts, ctx))
  			continue;
  		print_option_help(opts, full);
  	}
  
  	fputc('\n', stderr);
  
  	free(ordered);
  
  	return PARSE_OPT_HELP;
  }
  
  void usage_with_options(const char * const *usagestr,
  			const struct option *opts)
  {
  	usage_with_options_internal(usagestr, opts, 0, NULL);
  	exit(129);
  }
  
  void usage_with_options_msg(const char * const *usagestr,
  			    const struct option *opts, const char *fmt, ...)
  {
  	va_list ap;
  	char *tmp = error_buf;
  
  	va_start(ap, fmt);
  	if (vasprintf(&error_buf, fmt, ap) == -1)
  		die("vasprintf failed");
  	va_end(ap);
  
  	free(tmp);
  
  	usage_with_options_internal(usagestr, opts, 0, NULL);
  	exit(129);
  }
  
  int parse_options_usage(const char * const *usagestr,
  			const struct option *opts,
  			const char *optstr, bool short_opt)
  {
  	if (!usagestr)
  		goto opt;
  
  	fprintf(stderr, "\n Usage: %s\n", *usagestr++);
  	while (*usagestr && **usagestr)
  		fprintf(stderr, "    or: %s\n", *usagestr++);
  	while (*usagestr) {
  		fprintf(stderr, "%s%s\n",
  				**usagestr ? "    " : "",
  				*usagestr);
  		usagestr++;
  	}
  	fputc('\n', stderr);
  
  opt:
  	for (  ; opts->type != OPTION_END; opts++) {
  		if (short_opt) {
  			if (opts->short_name == *optstr) {
  				print_option_help(opts, 0);
  				break;
  			}
  			continue;
  		}
  
  		if (opts->long_name == NULL)
  			continue;
  
  		if (!prefixcmp(opts->long_name, optstr))
  			print_option_help(opts, 0);
  		if (!prefixcmp("no-", optstr) &&
  		    !prefixcmp(opts->long_name, optstr + 3))
  			print_option_help(opts, 0);
  	}
  
  	return PARSE_OPT_HELP;
  }
  
  
  int parse_opt_verbosity_cb(const struct option *opt,
  			   const char *arg __maybe_unused,
  			   int unset)
  {
  	int *target = opt->value;
  
  	if (unset)
  		/* --no-quiet, --no-verbose */
  		*target = 0;
  	else if (opt->short_name == 'v') {
  		if (*target >= 0)
  			(*target)++;
  		else
  			*target = 1;
  	} else {
  		if (*target <= 0)
  			(*target)--;
  		else
  			*target = -1;
  	}
  	return 0;
  }
  
  static struct option *
  find_option(struct option *opts, int shortopt, const char *longopt)
  {
  	for (; opts->type != OPTION_END; opts++) {
  		if ((shortopt && opts->short_name == shortopt) ||
  		    (opts->long_name && longopt &&
  		     !strcmp(opts->long_name, longopt)))
  			return opts;
  	}
  	return NULL;
  }
  
  void set_option_flag(struct option *opts, int shortopt, const char *longopt,
  		     int flag)
  {
  	struct option *opt = find_option(opts, shortopt, longopt);
  
  	if (opt)
  		opt->flags |= flag;
  	return;
  }
  
  void set_option_nobuild(struct option *opts, int shortopt,
  			const char *longopt,
  			const char *build_opt,
  			bool can_skip)
  {
  	struct option *opt = find_option(opts, shortopt, longopt);
  
  	if (!opt)
  		return;
  
  	opt->flags |= PARSE_OPT_NOBUILD;
  	opt->flags |= can_skip ? PARSE_OPT_CANSKIP : 0;
  	opt->build_opt = build_opt;
  }
  