/*
 * Copyright (C) 2016 Andre Noll <maan@tuebingen.mpg.de>
 *
 * Licensed under the LGPL v3, see https://www.gnu.org/licenses/lgpl-3.0.html
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <assert.h>
#include <stdarg.h>
#include <inttypes.h>
#include <errno.h>
#include <limits.h>

#include "lopsub-internal.h"
#include "lopsub.h"

/* For detecting version mismatches, see lopsub-internal.h. */
const unsigned LLS_ABI_VERSION_VAR = 0;

#define FOR_EACH_OPTION(_i, _opts) \
	for (_i = 0; (_opts) && (_opts)[(_i)].name; (_i)++)

#define FOR_EACH_OPTION_IN_COMMAND(_opt, _cmd) \
	for ( \
		(_opt) = (_cmd)->options; \
		(_opt) && (_opt) < (_cmd)->options + (_cmd)->num_options; \
		(opt)++ \
	)

/* The result of parsing one option and its arguments. */
struct lls_arg {
	int idx; /* index into either argv[] or the lls_option array. */
	const char *arg; /* NULL if option has no argument. */
};

/*
 * This structure, and the exchange_args(), decode_option() and parse_option()
 * functions below are inspired by the glibc implementation of getopt.c,
 * Copyright (C) 1987-2015 Free Software Foundation, Inc.
 */
struct lls_data {
	const struct lls_option *opts;
	int argc;
	char *const *argv;

	int optind; /* index into argv[] which we are parsing. */
	const char *next_char;
	/*
	 * These describe the part of argv[] that contains non-options that
	 * have been skipped. first_nonopt is the index in argv[] of the first
	 * of them, last_nonopt is the index after the last of them. Initially
	 * both indices are zero.
	 */
	int first_nonopt;
	int last_nonopt;
};

const struct lls_command *lls_cmd(unsigned cmd_num,
		const struct lls_suite *suite)
{
	if (cmd_num > suite->num_subcommands)
		return NULL;
	return suite->commands + cmd_num;
}

const char *lls_command_name(const struct lls_command *cmd)
{
	return cmd->name;
}

const void *lls_user_data(const struct lls_command *cmd)
{
	return cmd->user_data;
}

const struct lls_option *lls_opt(unsigned opt_num,
		const struct lls_command *cmd)
{
	return cmd->options + opt_num;
}

const struct lls_opt_result *lls_opt_result(unsigned opt_num,
		const struct lls_parse_result *lpr)
{
	return lpr->opt_result + opt_num;
}

unsigned lls_opt_given(const struct lls_opt_result *r)
{
	return r->given;
}

const char *lls_enum_string_val(unsigned idx, const struct lls_option *opt)
{
	return opt->values[idx].string_val;
}

const char *lls_string_val(unsigned idx, const struct lls_opt_result *r)
{
	return r->value[idx].string_val;
}

int32_t lls_int32_val(unsigned idx, const struct lls_opt_result *r)
{
	return r->value[idx].int32_val;
}

uint32_t lls_uint32_val(unsigned idx, const struct lls_opt_result *r)
{
	return r->value[idx].uint32_val;
}

int64_t lls_int64_val(unsigned idx, const struct lls_opt_result *r)
{
	return r->value[idx].int64_val;
}

uint64_t lls_uint64_val(unsigned idx, const struct lls_opt_result *r)
{
	return r->value[idx].uint64_val;
}

unsigned lls_num_inputs(const struct lls_parse_result *lpr)
{
	return lpr->num_inputs;
}

const char *lls_purpose(const struct lls_command *cmd)
{
	return cmd->purpose;
}

const char *lls_input(unsigned input_num, const struct lls_parse_result *lpr)
{
	return lpr->inputs[input_num];
}

const char *lls_strerror(int lss_errno)
{
	#define LLS_ERROR(_n, _s) _s,
	static const char * const error_string[] = {LLS_ERRORS NULL};
	#undef LLS_ERROR
	return error_string[lss_errno];
}

static int xrealloc(void *p, size_t size)
{
	void **pp = p, *newp = realloc(*pp, size);

	if (!newp)
		return -E_LLS_NOMEM;
	*pp = newp;
	return 0;
}

/* Print a formatted message to a dynamically allocated string. */
__attribute__ ((format (printf, 2, 0)))
static int xvasprintf(char **result, const char *fmt, va_list ap)
{
	int ret;
	size_t size = 150;
	va_list aq;

	if (!result)
		return 0;
	if (*result)
		free(*result);
	*result = malloc(size + 1);
	if (!*result)
		return -E_LLS_NOMEM;
	va_copy(aq, ap);
	ret = vsnprintf(*result, size, fmt, aq);
	va_end(aq);
	assert(ret >= 0);
	if (ret < size) /* OK */
		return ret;
	size = ret + 1;
	ret = xrealloc(result, size);
	if (ret < 0) {
		free(*result);
		*result = NULL;
		return ret;
	}
	va_copy(aq, ap);
	ret = vsnprintf(*result, size, fmt, aq);
	va_end(aq);
	assert(ret >= 0 && ret < size);
	return ret;
}

/* Print to a dynamically allocated string, variable number of arguments. */
__attribute__ ((format (printf, 2, 3)))
static int xasprintf(char **result, const char *fmt, ...)
{
	va_list ap;
	unsigned ret;

	va_start(ap, fmt);
	ret = xvasprintf(result, fmt, ap);
	va_end(ap);
	return ret;
}

static inline unsigned num_vals_in_parse_result(const struct lls_command *cmd,
	int opt_num, const struct lls_parse_result *lpr)
{
	const struct lls_option *opt = cmd->options + opt_num;
	struct lls_opt_result *lor = lpr->opt_result + opt_num;

	if (opt->arg_info == LLS_NO_ARGUMENT)
		return 0;
	if (lor->given == 0)
		return 1; /* for the default value */
	if (!(opt->flags & LLS_MULTIPLE))
		return 1;
	return lor->given;
}

union atoi_result {
	int32_t int32;
	uint32_t uint32;
	int64_t int64;
	uint64_t uint64;
};

enum atoi_mode {ATOI_INT32, ATOI_UINT32, ATOI_INT64, ATOI_UINT64};

/*
 * Convert a string to a 32 or 64 bit signed or unsigned integer value.
 *
 * For conversions to unsigned integers, negative values are considered valid
 * input and are silently converted.
 */
static int lls_atoi(const char *str, enum atoi_mode mode, union atoi_result *value)
{
	char *endptr;
	union atoi_result result;

	memset(value, 0, sizeof(*value));
	errno = 0; /* To distinguish success/failure after call */
	/*
	 * We pass zero as the base to strtoll(3) and strtoull(3) to let the
	 * function recognize an optional base prefix like "0x".
	 */
	if (mode == ATOI_UINT64) {
		unsigned long long tmp = strtoull(str, &endptr, 0);
		if (errno == ERANGE && tmp == ULLONG_MAX)
			return -E_LLS_OVERFLOW;
		result.uint64 = tmp;
	} else { /* parse as signed 64 bit and check range */
		long long tmp = strtoll(str, &endptr, 0);
		if (errno == ERANGE && (tmp == LLONG_MAX || tmp == LLONG_MIN))
			return -E_LLS_OVERFLOW;
		switch (mode) {
		case ATOI_INT64: /* no additional range check necessary */
			result.int64 = tmp;
			break;
		case ATOI_INT32:
			if (tmp < INT_MIN || tmp > INT_MAX)
				return -E_LLS_OVERFLOW;
			result.int32 = tmp;
			break;
		case ATOI_UINT32:
			if (tmp > UINT_MAX)
				return -E_LLS_OVERFLOW;
			result.uint32 = tmp;
			break;
		default:
			assert(0);
		}
	}
	/*
	 * If there were no digits at all, strtol() and friends store the
	 * original value of str in *endptr.
	 */
	if (endptr == str)
		return -E_LLS_NO_DIGITS;
	/*
	 * The implementation may also set errno (and return 0) in case no
	 * conversion was performed.
	 */
	if (errno != 0)
		return -E_LLS_NO_DIGITS;
	if (*endptr != '\0') /* Further characters after number */
		return -E_LLS_TRAILING_GARBAGE;
	*value = result;
	return 1;
}

static int atoi32(const char *str, int32_t *result)
{
	union atoi_result ar;
	int ret = lls_atoi(str, ATOI_INT32, &ar);
	*result = ar.int32;
	return ret;
}

static int atou32(const char *str, uint32_t *result)
{
	union atoi_result ar;
	int ret = lls_atoi(str, ATOI_UINT32, &ar);
	*result = ar.uint32;
	return ret;
}

static int atoi64(const char *str, int64_t *result)
{
	union atoi_result ar;
	int ret = lls_atoi(str, ATOI_INT64, &ar);
	*result = ar.int64;
	return ret;
}

static int atou64(const char *str, uint64_t *result)
{
	union atoi_result ar;
	int ret = lls_atoi(str, ATOI_UINT64, &ar);
	*result = ar.uint64;
	return ret;
}

static void free_opt_result(int opt_num, struct lls_parse_result *lpr,
		const struct lls_command *cmd)
{
	const struct lls_option *opt = cmd->options + opt_num;

	if (opt->arg_type == LLS_STRING && !opt->values) {
		unsigned num_vals = num_vals_in_parse_result(cmd, opt_num, lpr);
		int j;
		for (j = 0; j < num_vals; j++)
			if (lpr->opt_result[opt_num].value)
				free(lpr->opt_result[opt_num].value[j].string_val);
	}
	if (opt->arg_info != LLS_NO_ARGUMENT)
		free(lpr->opt_result[opt_num].value);
}

void lls_free_parse_result(struct lls_parse_result *lpr,
		const struct lls_command *cmd)
{
	int i;

	if (!lpr)
		return;
	if (lpr->inputs)
		for (i = 0; i < lpr->num_inputs; i++)
			free(lpr->inputs[i]);
	free(lpr->inputs);
	if (lpr->opt_result)
		FOR_EACH_OPTION(i, cmd->options)
			free_opt_result(i, lpr, cmd);
	free(lpr->opt_result);
	free(lpr);
}

static struct lls_data *init_lls_data(const struct lls_option *opts,
		int argc, char *const *argv)
{
	struct lls_data *d = malloc(sizeof(*d));

	if (!d)
		return NULL;
	d->optind = 0;
	/* start with an empty non-option list */
	d->first_nonopt = d->last_nonopt = d->optind;
	d->opts = opts;
	d->argc = argc;
	d->argv = argv;
	d->next_char = NULL;
	return d;
}

/*
 * Exchange two adjacent subsets of argv[].
 *
 * One subset is given by indices {first_nonopt, ..., last_nonopt - 1}. It
 * contains all the non-options that have been skipped so far. The other subset
 * corresponds to indices {last_nonopt, ... optind - 1} which contains all the
 * options processed since those non-options were skipped.
 *
 * Before the function returns, ->first_nonopt and ->last_nonopt are updated to
 * describe the new set of non-options in argv[].
 */
static void exchange_args(struct lls_data *d)
{
	int bottom = d->first_nonopt;
	int middle = d->last_nonopt;
	int top = d->optind;
	char **argv = (char **)d->argv;

	/*
	 * Exchange the shorter segment with the far end of the longer segment.
	 * That puts the shorter segment into the right place. It leaves the
	 * longer segment in the right place overall, but it consists of two
	 * parts that need to be swapped next.
	*/
	while (top > middle && middle > bottom) {
		if (top - middle > middle - bottom) {
			/* Bottom segment is the short one.  */
			int i, len = middle - bottom;

			/* Swap it with the top part of the top segment. */
			for (i = 0; i < len; i++) {
				char *tmp = argv[bottom + i];
				argv[bottom + i] = argv[top - (middle - bottom) + i];
				argv[top - (middle - bottom) + i] = tmp;
			}
			/* Exclude the moved bottom segment from further swapping. */
			top -= len;
		} else {
			/* Top segment is the short one.  */
			int i, len = top - middle;
			/* Swap it with the bottom part of the bottom segment. */
			for (i = 0; i < len; i++) {
				char *tmp = argv[bottom + i];
				argv[bottom + i] = argv[middle + i];
				argv[middle + i] = tmp;
			}
			/* Exclude the moved top segment from further swapping. */
			bottom += len;
		}
	}
	/* Update records for the slots the non-options now occupy. */
	d->first_nonopt += d->optind - d->last_nonopt;
	d->last_nonopt = d->optind;
}

/* whether arg points to an option argument */
static inline bool is_option(const char *arg)
{
	return arg[0] == '-' && arg[1] != '\0';
}

static void check_errctx(char **errctx, int ret)
{
	if (!errctx)
		return;
	if (ret >= 0)
		assert(!*errctx); /* memory leak/uninitialized pointer */
	else if (ret != -E_LLS_NOMEM)
		assert(*errctx); /* we must provide an error message */
}

/*
 * Decode the current option. On success, set result->idx to the index in the
 * ->options array which was decoded successfully. On failure, result->idx is
 * the index in argv[] which could not be parsed.
 */
static int decode_option(struct lls_data *d, struct lls_arg *result,
		char **errctx)
{
	const char *word = d->argv[d->optind], *cur, *end;
	size_t len;
	int i;
	const struct lls_option *match = NULL;
	bool ambig = false, shortopt;

	assert(word[0] != '\0');
	shortopt = word[1] != '-';
	result->idx = d->optind;
	result->arg = word;

	if (d->next_char)
		cur = d->next_char;
	else
		cur = word + 1 + !shortopt; /* skip dash(es) */
	for (end = cur; *end && *end != '='; end++)
		; /* nothing */
	len = end - cur;

	/* test all options for exact or abbreviated matches */
	FOR_EACH_OPTION(i, d->opts) {
		const struct lls_option *opt = d->opts + i;
		if (opt->flags & LLS_IGNORED)
			continue;
		if (shortopt) {
			if (*cur != opt->short_opt)
				continue;
			match = opt;
			d->next_char = cur + 1;
			if (d->next_char[0] == '\0' || d->next_char[0] == '=')
				d->next_char = NULL;
			break;
		}
		if (strncmp(opt->name, cur, len) != 0)
			continue;
		if (strlen(opt->name) == len) { /* exact match */
			match = opt;
			break;
		}
		if (match) { /* second non-exact match */
			ambig = true;
			break;
		}
		/* first non-exact match */
		match = opt;
	}
	if (!match) { /* option not found */
		xasprintf(errctx, "error token: %s", cur);
		return -E_LLS_BAD_OPTION;
	}
	if (ambig) {
		xasprintf(errctx, "%s", word);
		return -E_LLS_AMBIG_OPTION;
	}
	if (d->next_char) {
		if (match->arg_info == LLS_REQUIRED_ARGUMENT) {
			xasprintf(errctx, "--%s", match->name);
			return -E_LLS_NO_ARG_GIVEN;
		}
		result->arg = NULL;
		goto success;
	}
	d->optind++;
	if (*end == '=') {
		if (match->arg_info == LLS_NO_ARGUMENT) {
			xasprintf(errctx, "--%s", match->name);
			return -E_LLS_ARG_GIVEN;
		}
		result->arg = end + 1;
	} else if (match->arg_info == LLS_REQUIRED_ARGUMENT) {
		if (d->optind >= d->argc) {
			xasprintf(errctx, "--%s", match->name);
			return -E_LLS_NO_ARG_GIVEN;
		}
		result->arg = d->argv[d->optind++];
	} else
		result->arg = NULL;
success:
	result->idx = match - d->opts;
	return 1;
}

/*
 * Parse one option, including its argument (if any).
 *
 * We permute the contents of ARGV as we scan, so that eventually all the
 * non-options are at the end. This allows options to be given in any order.
 *
 * Returns zero on end-of-argv, negative on errors, one if an option was parsed
 * successfully. The structure pointed to by result is initialized as follows:
 *
 * end-of-args case: ->idx is the index of first non-option in argv[], ->arg is
 * argv[result->idx].
 *
 * error case: ->idx is the index of the first problematic option in argv. ->arg is
 * argv[result->idx] as in the end-of-args case.
 *
 * success case: ->idx is the index into the option array which corresponds to
 * the option that was parsed successfully, ->arg its argument, or NULL if no
 * argument was given.
 *
 * After this function returned non-positive, it must not be called again.
 */
static int parse_option(struct lls_data *d, struct lls_arg *result, char **errctx)
{
	assert(d->last_nonopt <= d->optind);
	assert(d->first_nonopt <= d->optind);

	if (d->next_char)
		return decode_option(d, result, errctx);
	/*
	 * If we have just processed some options following some non-options,
	 * exchange them so that the options come first.
	 */
	if (d->first_nonopt != d->last_nonopt && d->last_nonopt != d->optind)
		exchange_args(d);
	else if (d->last_nonopt != d->optind)
		d->first_nonopt = d->optind;
	/*
	 * Skip any additional non-options and extend the range of non-options
	 * previously skipped.
	 */
	while (d->optind < d->argc && !is_option(d->argv[d->optind]))
		d->optind++;
	d->last_nonopt = d->optind;
	/*
	 * The special argument `--' forces an end of option-scanning. We skip
	 * it like a null option, then exchange it with previous non-options as
	 * if it were an option. Then we skip everything else like a non-option.
	 */
	if (d->optind != d->argc && !strcmp(d->argv[d->optind], "--")) {
		d->optind++;
		if (d->first_nonopt != d->last_nonopt && d->last_nonopt != d->optind)
			exchange_args(d);
		else if (d->first_nonopt == d->last_nonopt)
			d->first_nonopt = d->optind;
		d->last_nonopt = d->argc;
		d->optind = d->argc;
	}
	/*
	 * If we have done all the argv elements, stop the scan and back over
	 * any non-options that we skipped and permuted.
	 */
	if (d->optind == d->argc) {
		/*
		 * Set the index to point at the non-options that we
		 * previously skipped.
		 */
		result->idx = d->first_nonopt;
		result->arg = d->argv[result->idx];
		return 0;
	}
	assert(is_option(d->argv[d->optind]));
	return decode_option(d, result, errctx);
}

static int check_enum_arg(const char *arg, const struct lls_option *opt,
		char **errctx)
{
	int i;
	char *val;

	for (i = 0; (val = opt->values[i].string_val); i++)
		if (!strcmp(arg, val))
			return i;
	xasprintf(errctx, "arg: %s, option: %s", arg, opt->name);
	return -E_LLS_ENUM;
}

/*
 * Increase the "given" count and store argument if the option takes one.
 * Allocates or reallocates the ->value array of struct lls_opt_result in lpr.
 */
static int lls_parse_arg(struct lls_arg *la, const struct lls_option *opts,
		struct lls_parse_result *lpr, char **errctx)
{
	const struct lls_option *opt = opts + la->idx;
	struct lls_opt_result *lor = lpr->opt_result + la->idx;
	bool multiple;
	int idx, ret;

	if (la->arg && opt->arg_info == LLS_NO_ARGUMENT) {
		xasprintf(errctx, "arg: %s, option: %s", la->arg, opt->name);
		return -E_LLS_ARG_GIVEN;
	}
	multiple = opt->flags & LLS_MULTIPLE;
	if (opt->arg_type == LLS_STRING && !opt->values && !multiple) {
		if (lor->value) { /* discard previous value */
			free(lor->value[0].string_val);
			free(lor->value);
			lor->value = NULL;
		}
	}
	if (!la->arg)
		goto success;
	idx = multiple? lor->given : 0;
	if (!lor->value || multiple) {
		ret = xrealloc(&lor->value, (idx + 1) * sizeof(*lor->value));
		if (ret < 0) {
			xasprintf(errctx, "option value array for --%s",
				opt->name);
			return ret;
		}
	}
	switch (opt->arg_type) {
	case LLS_STRING:
		if (opt->values) {
			ret = check_enum_arg(la->arg, opt, errctx);
			if (ret < 0)
				return ret;
			lor->value[idx].uint32_val = ret;
		} else {
			lor->value[idx].string_val = strdup(la->arg);
			if (!lor->value[idx].string_val) {
				xasprintf(errctx, "string value for %s",
					opt->name);
				return -E_LLS_NOMEM;
			}
		}
		break;
	case LLS_INT32:
		ret = atoi32(la->arg, &lor->value[idx].int32_val);
		if (ret < 0)
			goto atoi_error;
		break;
	case LLS_UINT32:
		ret = atou32(la->arg, &lor->value[idx].uint32_val);
		if (ret < 0)
			goto atoi_error;
		break;
	case LLS_INT64:
		ret = atoi64(la->arg, &lor->value[idx].int64_val);
		if (ret < 0)
			goto atoi_error;
		break;
	case LLS_UINT64:
		ret = atou64(la->arg, &lor->value[idx].uint64_val);
		if (ret < 0)
			goto atoi_error;
		break;
	default:
		assert(false);
	}
success:
	lor->given++;
	return 1;
atoi_error:
	assert(ret < 0);
	xasprintf(errctx, "conversion error for argument \"%s\" to option --%s",
		la->arg, opt->name);
	return ret;
}

static int copy_val(union lls_val *dst, const union lls_val *src,
		const struct lls_option *opt, char **errctx)
{
	if (opt->arg_type != LLS_STRING || opt->values) {
		*dst = *src;
		return 0;
	}
	if (!src->string_val) {
		dst->string_val = NULL;
		return 0;
	}
	dst->string_val = strdup(src->string_val);
	if (!dst->string_val) {
		xasprintf(errctx, "copy value for --%s", opt->name);
		return -E_LLS_NOMEM;
	}
	return 1;
}

int lls_check_arg_count(const struct lls_parse_result *lpr,
		int min_argc, int max_argc, char **errctx)
{
	if (errctx)
		*errctx = NULL;
	assert(min_argc <= max_argc);
	if (lpr->num_inputs < min_argc) {
		xasprintf(errctx, "%s %u non-option args required, %u given",
			min_argc < max_argc? "at least" : "exactly",
			min_argc, lpr->num_inputs);
		return -E_LLS_BAD_ARG_COUNT;
	}
	if (lpr->num_inputs > max_argc) {
		if (max_argc == 0)
			xasprintf(errctx, "no non-option args allowed, "
				"%u given", lpr->num_inputs);
		else
			xasprintf(errctx, "%s %u non-option args %s, %u given",
				min_argc < max_argc? "at most" : "exactly",
				max_argc,
				min_argc < max_argc? "allowed" : "required",
				lpr->num_inputs);
		return -E_LLS_BAD_ARG_COUNT;
	}
	return 1;
}

/*
 * Unlike getopt(3) this implementation can not resume the scan where it left
 * off.
 */
int lls_parse(int argc, char **argv, const struct lls_command *cmd,
		struct lls_parse_result **lprp, char **errctx)
{
	const struct lls_option *opts = cmd->options;
	struct lls_data *d = NULL;
	int i, ret;
	struct lls_arg la;
	struct lls_parse_result *lpr;

	if (errctx)
		*errctx = NULL;
	lpr = calloc(1, sizeof(*lpr));
	if (!lpr) {
		xasprintf(errctx, "log parse result");
		ret = -E_LLS_NOMEM;
		goto out;
	}
	d = init_lls_data(opts, argc, argv);
	if (!d) {
		xasprintf(errctx, "init_lls_data()");
		ret = -E_LLS_NOMEM;
		goto out;
	}
	if (cmd->num_options == 0) {
		la.idx = 0;
		lpr->opt_result = NULL;
	} else {
		lpr->opt_result = calloc(cmd->num_options,
			sizeof(*lpr->opt_result));
		if (!lpr->opt_result) {
			xasprintf(errctx, "option result array for %s",
				cmd->name);
			ret = -E_LLS_NOMEM;
			goto out;
		}
		for (;;) {
			ret = parse_option(d, &la, errctx);
			if (ret < 0)
				goto out;
			if (ret == 0)
				break;
			ret = lls_parse_arg(&la, opts, lpr, errctx);
			if (ret < 0)
				goto out;
		}
	}
	lpr->num_inputs = argc - la.idx - 1;
	if (!cmd->non_opts_name) {
		ret = lls_check_arg_count(lpr, 0, 0, errctx);
		if (ret < 0) {
			/* needed for lls_free_parse_result() */
			lpr->inputs = NULL;
			goto out;
		}
	}
	/* We always make a copy of the elements of argv[] */
	lpr->inputs = malloc((lpr->num_inputs + 1) * sizeof(char *));
	if (!lpr->inputs) {
		xasprintf(errctx, "inputs array for %s", cmd->name);
		ret = -E_LLS_NOMEM;
		goto out;
	}
	for (i = 0; i < lpr->num_inputs; i++) {
		char *arg = argv[i + la.idx + 1];
		lpr->inputs[i] = strdup(arg);
		if (lpr->inputs[i])
			continue;
		xasprintf(errctx, "option #%d (%s) of %s", i, arg, cmd->name);
		ret = -E_LLS_NOMEM;
		goto out;
	}
	lpr->inputs[lpr->num_inputs] = NULL;
	/* initialize default values */
	FOR_EACH_OPTION(i, opts) {
		const struct lls_option *opt = opts + i;
		struct lls_opt_result *lor = lpr->opt_result + i;
		bool required = opt->flags & LLS_REQUIRED;
		bool has_arg = opt->arg_info != LLS_NO_ARGUMENT;

		if (lor->given == 0 && required) {
			xasprintf(errctx, "--%s", opt->name);
			ret = -E_LLS_OPT_MANDATORY;
			goto out;
		}
		if (lor->value)
			continue;
		if (!has_arg)
			continue;
		/*
		 * allocate space for the default value, even if there is no
		 * default given in the .suite file
		 */
		lor->value = malloc(sizeof(*lor->value));
		if (!lor->value) {
			xasprintf(errctx, "value array for --%s", opt->name);
			ret = -E_LLS_NOMEM;
			goto out;
		}
		ret = copy_val(lor->value, &opt->default_val, opt, errctx);
		if (ret < 0)
			goto out;
	}
	ret = 1;
out:
	free(d);
	check_errctx(errctx, ret);
	if (ret < 0) {
		lls_free_parse_result(lpr, cmd);
		*lprp = NULL;
	} else
		*lprp = lpr;
	return ret;
}

#define MAX_OPTION_LEN 30
#define HELP_INDENT 6
static const char space[MAX_OPTION_LEN + 1] = "                              ";

static int short_option_help(const struct lls_option *opt, char **result)
{
	int ret = 0;
	char *opt_names = NULL;
	bool overlong, has_short = opt->short_opt;
	const char *typestr;

	*result = NULL;
	if (opt->flags & LLS_IGNORED)
		return xasprintf(result, "%s", opt->summary);
	if (opt->arg_info == LLS_NO_ARGUMENT)
		typestr = "";
	else
		typestr = opt->typestr? opt->typestr : "val";

	ret = xasprintf(&opt_names,
		"%s%c%s"
		" --%s"
		"%s%s%s%s%s"
		,
		has_short? "  -" : "   ",
		has_short? opt->short_opt : ' ',
		has_short? "," : " ",
		opt->name,
		opt->arg_info == LLS_OPTIONAL_ARGUMENT? "[" : "",
		opt->arg_info == LLS_NO_ARGUMENT? "" : "=<",
		typestr,
		opt->arg_info == LLS_NO_ARGUMENT? "" : ">",
		opt->arg_info == LLS_OPTIONAL_ARGUMENT? "]" : ""
	);
	if (ret < 0)
		return ret;
	overlong = ret >= MAX_OPTION_LEN;
	ret = xasprintf(result,
		"%s"
		"%s"
		"%s"
		"%s"
		,
		opt_names,
		overlong? "\n" : "",
		overlong? space : space + ret,
		opt->summary? opt->summary : ""
	);
	free(opt_names);
	return ret;
}

static int format_default_val(const struct lls_option *opt, char **result)
{
	const union lls_val *val = &opt->default_val;

	*result = NULL;
	if (opt->arg_info == LLS_NO_ARGUMENT)
		return 0;
	if (!(opt->flags & LLS_HAS_DEFAULT))
		return 0;
	switch (opt->arg_type) {
	case LLS_STRING:
		if (opt->values)
			return 0;
		return xasprintf(result, "(string, default: %s)",
			val->string_val? val->string_val : "[NULL]");
	case LLS_INT32:
		return xasprintf(result, "(int32, default: %" PRId32 ")",
			val->int32_val);
	case LLS_UINT32:
		return xasprintf(result, "(uint32, default: %" PRIu32 ")",
			val->uint32_val);
	case LLS_INT64:
		return xasprintf(result, "(int64, default: %" PRId64 ")",
			val->int64_val);
	case LLS_UINT64:
		return xasprintf(result, "(uint64, default: %" PRIu64 ")",
			val->uint64_val);
	default:
		assert(0);
	}
	return 1;
}

static int format_values(const struct lls_option *opt, char **result)
{
	int i;
	uint32_t dflt_idx;
	const char *val, *pfx = "values: ";
	size_t len, line_len;
	const int indent_len = 6, max_len = 75, pfx_len = 8;
	char *p;

	*result = NULL;
	if (!opt->values)
		return 0;
	assert(opt->arg_type == LLS_STRING);
	dflt_idx = opt->default_val.uint32_val;
	line_len = indent_len + pfx_len;
	len = line_len;
	for (i = 0; (val = opt->values[i].string_val); i++) {
		size_t val_len = strlen(val);
		/* comma and space, and [] around default val */
		int extra_len = 2 * (i != 0) + 2 * (i == dflt_idx);
		bool cr = line_len + val_len + extra_len > max_len;
		if (cr) {
			line_len = indent_len + pfx_len;
			len += 1 + indent_len + pfx_len; /* +1 for \n */
		}
		len += val_len + extra_len;
		line_len += val_len + extra_len;
	}
	*result = malloc(len + 1); /* +1 for terminating zero byte */
	if (!*result)
		return -E_LLS_NOMEM;
	p = *result + sprintf(*result, "%.*s%s", indent_len, space, pfx);
	line_len = p - *result;
	for (i = 0; (val = opt->values[i].string_val); i++) {
		size_t val_len = strlen(val);
		int extra_len = 2 * (i != 0) + 2 * (i == dflt_idx);
		bool cr = line_len + val_len + extra_len > max_len;
		p += sprintf(p,
			"%s"
			"%s"
			"%.*s"
			"%s%s%s",
			i == 0? "" : ", ",
			cr? "\n" : "",
			cr? pfx_len + indent_len : 0, cr? space : "",
			i == dflt_idx? "[" : "", val, i == dflt_idx? "]" : ""
		);
		if (cr)
			line_len = indent_len + pfx_len;
		line_len += val_len + extra_len;
	}
	return 1;
}

static char *create_help_buf(const struct lls_command *cmd, bool long_help)
{
	char *header, *option_help, *result;
	const struct lls_option *opt;
	int ret;
	const char *desc = (long_help && cmd->description)?
		cmd->description : "";
	const char *closing = (long_help && cmd->closing)? cmd->closing : NULL;

	result = NULL;
	header = NULL;
	ret = xasprintf(&header,
		"%s - %s\n\n"
		"Usage: %s %s\n"
		"%s%s"
	,
		cmd->name, cmd->purpose,
		cmd->name, cmd->synopsis,
		desc,
		cmd->options? "\n" : ""
	);
	if (ret < 0)
		return NULL;
	if (!cmd->options)
		return header;
	option_help = NULL;
	FOR_EACH_OPTION_IN_COMMAND(opt, cmd) {
		char *tmp, *soh, *loh = NULL, *dflt, *values;
		int indent = (opt->flags & LLS_IGNORED)? 0 : HELP_INDENT;

		ret = short_option_help(opt, &soh);
		if (ret < 0)
			goto out;
		if (long_help && opt->help) {
			const char *p, *q;
			for (p = opt->help; (q = strchr(p, '\n')); p = q + 1) {
				tmp = NULL;
				ret = xasprintf(&tmp, "%s%.*s%.*s",
					loh? loh : "\n", indent, space,
					(int)(q - p + 1), p);
				free(loh);
				if (ret < 0) {
					free(soh);
					goto out;
				}
				loh = tmp;
			}
		}
		ret = format_default_val(opt, &dflt);
		if (ret < 0) {
			free(soh);
			free(loh);
			goto out;
		}
		if (long_help) {
			ret = format_values(opt, &values);
			if (ret < 0) {
				free(dflt);
				free(soh);
				free(loh);
				goto out;
			}
		} else
			values = NULL;
		tmp = NULL;
		ret = xasprintf(&tmp,
			"%s"
			"%s"
			"%s%s%s"
			"%s%s"
			"%s\n",
			option_help? option_help : "",
			soh ? soh : "",
			dflt? "\n" : "", dflt? space : "", dflt? dflt : "",
			values? "\n" : "", values? values : "",
			loh? loh : ""
		);
		free(values);
		free(dflt);
		free(soh);
		free(loh);
		if (ret < 0)
			goto out;
		free(option_help);
		option_help = tmp;
	}
	ret = xasprintf(&result, "%s%s%s%s", header, option_help,
		closing? "\n" : "", closing? closing : "");
out:
	free(header);
	free(option_help);
	return ret < 0? NULL : result;
}

char *lls_long_help(const struct lls_command *cmd)
{
	return create_help_buf(cmd, true /* include help */);
}

char *lls_short_help(const struct lls_command *cmd)
{
	return create_help_buf(cmd, false /* only options */);
}

static int partial_match(const char *arg, const char *name)
{
	size_t arglen = strlen(arg);

	if (strncmp(arg, name, arglen) != 0)
		return 1; /* no match */
	if (name[arglen] == '\0')
		return 0; /* exact match */
	return -1; /* partial match */
}

int lls_lookup_subcmd(const char *string, const struct lls_suite *suite,
		char **errctx)
{
	int i, ret;

	if (errctx)
		*errctx = NULL;
	if (!string) {
		xasprintf(errctx, "nothing to look up");
		return -E_LLS_BAD_SUBCMD;
	}
	ret = 0; /* no match so far */
	for (i = 1; i <= suite->num_subcommands; i++) {
		switch (partial_match(string, suite->commands[i].name)) {
		case 1: /* no match */
			continue;
		case 0: /* exact match */
			return i;
		case -1: /* partial match */
			if (ret > 0) {
				ret = -E_LLS_AMBIG_SUBCMD;
				goto fail;
			}
			ret = i;
		}
	}
	if (ret > 0) /* unique partial match */
		return ret;
	ret = -E_LLS_BAD_SUBCMD;
fail:
	xasprintf(errctx, "%s", string);
	return ret;
}

static size_t get_opt_result_pointer(const struct lls_option *opt, int val_num,
		struct lls_opt_result *lor, void **result)
{
	union lls_val *val = lor->value + val_num;

	switch (opt->arg_type) {
	case LLS_INT32:
		*result = &val->int32_val;
		return 4;
	case LLS_UINT32:
		*result = &val->uint32_val;
		return 4;
	case LLS_INT64:
		*result = &val->int64_val;
		return 8;
	case LLS_UINT64:
		*result = &val->uint64_val;
		return 8;
	default:
		assert(0);
	}
}

/* never fails, returns number of bytes needed/written */
static size_t serialize_parse_result(const struct lls_parse_result *lpr,
	const struct lls_command *cmd, char *result)
{
	int i, j;
	size_t nbytes;

	/* num_inputs */
	if (result)
		memcpy(result, &lpr->num_inputs, 4);
	nbytes = 4;

	/* inputs */
	for (i = 0; i < lpr->num_inputs; i++) {
		if (result)
			strcpy(result + nbytes, lpr->inputs[i]);
		nbytes += strlen(lpr->inputs[i]) + 1;
	}
	/* options */
	FOR_EACH_OPTION(i, cmd->options) {
		const struct lls_option *opt = cmd->options + i;
		struct lls_opt_result *lor = lpr->opt_result + i;
		unsigned num_vals;

		if (result)
			memcpy(result + nbytes, &lor->given, 4);
		nbytes += 4;
		if (opt->arg_info == LLS_NO_ARGUMENT)
			continue;
		num_vals = num_vals_in_parse_result(cmd, i, lpr);
		if (opt->arg_type == LLS_STRING && !opt->values) {
			for (j = 0; j < num_vals; j++) {
				if (result)
					strcpy(result + nbytes,
						lor->value[j].string_val);
				nbytes += strlen(lor->value[j].string_val) + 1;
			}
		} else {
			for (j = 0; j < num_vals; j++) {
				size_t bytes;
				void *p;
				bytes = get_opt_result_pointer(opt, j, lor, &p);
				if (result)
					memcpy(result + nbytes, p, bytes);
				nbytes += bytes;
			}
		}
	}
	return nbytes;
}

int lls_serialize_parse_result(const struct lls_parse_result *lpr,
	const struct lls_command *cmd, char **result, size_t *nbytes)
{
	size_t sz;
	int ret;

	if (!result || !*result) { /* need to compute needed space */
		sz = serialize_parse_result(lpr, cmd, NULL);
		if (!result) { /* just report needed space */
			ret = 0;
			goto out;
		}
		*result = malloc(sz);
		if (!*result) {
			sz = 0;
			ret = -E_LLS_NOMEM;
			goto out;
		}
	}
	/* serialize it */
	sz = serialize_parse_result(lpr, cmd, *result);
	ret = 1;
out:
	if (nbytes)
		*nbytes = sz;
	return ret;
}

int lls_deserialize_parse_result(const char *buf, const struct lls_command *cmd,
		struct lls_parse_result **lprp)
{
	int i, j;
	const char *p = buf;
	struct lls_parse_result *lpr;

	*lprp = NULL;
	lpr = malloc(sizeof(*lpr));
	if (!lpr)
		return -E_LLS_NOMEM;
	memcpy(&lpr->num_inputs, p, 4);
	p += 4;
	if (lpr->num_inputs > 0) {
		lpr->inputs = malloc(lpr->num_inputs * sizeof(char *));
		if (!lpr->inputs)
			goto free_lpr;
	} else
		lpr->inputs = NULL;
	for (i = 0; i < lpr->num_inputs; i++) {
		lpr->inputs[i] = strdup(p);
		if (!lpr->inputs[i])
			goto free_inputs;
		p += strlen(p) + 1;
	}
	lpr->opt_result = malloc(cmd->num_options * sizeof(*lpr->opt_result));
	if (!lpr->opt_result)
		goto free_inputs;
	FOR_EACH_OPTION(i, cmd->options) {
		const struct lls_option *opt = cmd->options + i;
		struct lls_opt_result *lor = lpr->opt_result + i;
		uint32_t num_vals;

		memcpy(&lor->given, p, 4);
		p += 4;
		if (opt->arg_info == LLS_NO_ARGUMENT)
			continue;
		num_vals = num_vals_in_parse_result(cmd, i, lpr);
		lor->value = malloc(num_vals * sizeof(*lor->value));
		if (!lor->value)
			goto free_options;
		if (opt->arg_type == LLS_STRING && !opt->values) {
			for (j = 0; j < num_vals; j++) {
				lor->value[j].string_val = strdup(p);
				if (!lor->value[j].string_val) {
					for (; j >= 0; j--)
						free(lor->value[j].string_val);
					free(lor->value);
					goto free_options;
				}
				p += strlen(lor->value[j].string_val) + 1;
			}
		} else {
			for (j = 0; j < num_vals; j++) {
				size_t bytes;
				void *q;
				bytes = get_opt_result_pointer(opt, j, lor, &q);
				memcpy(q, p, bytes);
				p += bytes;
			}
		}
	}
	*lprp = lpr;
	return 1;
free_options:
	for (i--; i >= 0; i--) {
		const struct lls_option *opt = cmd->options + i;
		struct lls_opt_result *lor = lpr->opt_result + i;
		unsigned num_vals = (opt->flags & LLS_MULTIPLE)? lor->given : 1;
		for (j = 0; j < num_vals; j++)
			if (opt->arg_type == LLS_STRING && !opt->values)
				free(lor->value[j].string_val);
		free(lor->value);
	}
	free(lpr->opt_result);
free_inputs:
	for (; i >= 0; i--)
		free(lpr->inputs[i]);
	free(lpr->inputs);
free_lpr:
	free(lpr);
	return -E_LLS_NOMEM;
}

static int merge_option(int opt_num, const struct lls_parse_result *primary,
		const struct lls_parse_result *secondary,
		const struct lls_command *cmd, struct lls_parse_result *result,
		char **errctx)
{
	int l, m, ret;
	const struct lls_option *opt = cmd->options + opt_num;
	struct lls_opt_result *lor1, *lor2, *lor;

	lor1 = primary->opt_result + opt_num;
	lor2 = secondary->opt_result + opt_num;
	lor = result->opt_result + opt_num;
	lor->given = lor1->given + lor2->given;
	if (opt->arg_info == LLS_NO_ARGUMENT)
		return 0;
	if (lor->given > 0 && (opt->flags & LLS_MULTIPLE)) {
		lor->value = malloc(lor->given * sizeof(*lor->value));
		if (!lor->value) {
			xasprintf(errctx, "value array for option %s", opt->name);
			goto fail;
		}
		for (l = 0; l < lor1->given; l++) {
			ret = copy_val(lor->value + l, lor1->value + l,
				opt, errctx);
			if (ret < 0)
				goto free_primary_options;
		}
		for (m = 0; m < lor2->given; m++) {
			ret = copy_val(lor->value + l + m, lor2->value + m,
				opt, errctx);
			if (ret < 0)
				goto free_secondary_options;
		}
		return 1;
	}
	lor->value = malloc(sizeof(*lor->value)); /* one value only */
	if (!lor->value) {
		xasprintf(errctx, "(single) value for option %s", opt->name);
		goto fail;
	}
	if (lor1->given) {
		ret = copy_val(lor->value, lor1->value, opt, errctx);
		if (ret < 0)
			goto free_value;
	} else if (lor2->given) {
		ret = copy_val(lor->value, lor2->value, opt, errctx);
		if (ret < 0)
			goto free_value;
	} else {
		ret = copy_val(lor->value, &opt->default_val, opt, errctx);
		if (ret < 0)
			goto free_value;
	}
	return 1;
free_secondary_options:
	if (opt->arg_type == LLS_STRING && !opt->values)
		for (m--; m >= 0; m--)
			free(lor->value[l + m].string_val);
free_primary_options:
	if (opt->arg_type == LLS_STRING && !opt->values)
		for (l--; l >= 0; l--)
			free(lor->value[l].string_val);
free_value:
	free(lor->value);
fail:
	return -E_LLS_NOMEM;
}

int lls_merge(const struct lls_parse_result *primary,
		const struct lls_parse_result *secondary,
		const struct lls_command *cmd, struct lls_parse_result **lprp,
		char **errctx)
{
	int i, j, k, ret;
	unsigned num = primary->num_inputs + secondary->num_inputs;
	struct lls_parse_result *result;

	if (errctx)
		*errctx = NULL;
	result = malloc(sizeof(*result));
	if (!result) {
		ret = -E_LLS_NOMEM;
		xasprintf(errctx, "parse result");
		goto fail;
	}
	result->inputs = malloc((num + 1) * sizeof(char *));
	if (!result->inputs) {
		ret = -E_LLS_NOMEM;
		xasprintf(errctx, "inputs array of size %u", num);
		goto free_parse_result;
	}
	for (i = 0; i < primary->num_inputs; i++) {
		result->inputs[i] = strdup(primary->inputs[i]);
		if (!result->inputs[i]) {
			ret = -E_LLS_NOMEM;
			xasprintf(errctx, "primary input #%d", i);
			goto free_primary_inputs;
		}
	}
	for (j = 0; j < secondary->num_inputs; j++) {
		result->inputs[i + j] = strdup(secondary->inputs[j]);
		if (!result->inputs[i + j]) {
			ret = -E_LLS_NOMEM;
			xasprintf(errctx, "secondary input #%d", i);
			goto free_secondary_inputs;
		}
	}
	result->inputs[i + j] = NULL;
	result->opt_result = malloc(cmd->num_options
		* sizeof(*result->opt_result));
	if (!result->opt_result)
		goto free_secondary_inputs;
	FOR_EACH_OPTION(k, cmd->options) {
		ret = merge_option(k, primary, secondary, cmd, result, errctx);
		if (ret < 0)
			goto free_opt_results;
	}
	result->num_inputs = num;
	*lprp = result;
	ret = 1;
	goto out;
free_opt_results:
	for (k--; k >= 0; k--)
		free_opt_result(k, result, cmd);
free_secondary_inputs:
	for (j--; j >= 0; j--)
		free(result->inputs[i + j]);
free_primary_inputs:
	for (i--; i >= 0; i--)
		free(result->inputs[i]);
	free(result->inputs);
free_parse_result:
	free(result);
fail:
	assert(ret < 0);
	*lprp = NULL;
out:
	check_errctx(errctx, ret);
	return ret;
}

static bool is_default_val(const union lls_val *val,
		const struct lls_option *opt)
{
	bool has_default = opt->flags & LLS_HAS_DEFAULT;
	bool has_arg = opt->arg_info != LLS_NO_ARGUMENT;
	const union lls_val *dflt;

	if (!has_arg)
		return false;
	if (!has_default)
		return false;
	dflt = &opt->default_val;
	switch (opt->arg_type) {
	case LLS_INT32:
		return val->int32_val == dflt->int32_val;
	case LLS_UINT32:
		return val->uint32_val == dflt->uint32_val;
	case LLS_INT64:
		return val->int64_val == dflt->int64_val;
	case LLS_UINT64:
		return val->uint64_val == dflt->uint64_val;
	case LLS_STRING:
		{
		const char *s1, *s2;

		if (opt->values)
			return val->uint32_val == dflt->uint32_val;
		s1 = val->string_val;
		s2 = dflt->string_val;
		if (!s1 && !s2)
			return true;
		if (!s1 || !s2)
			return false;
		return !strcmp(s1, s2);
		}
	default:
		assert(0);
	}
}

static char *append_opt_val(const union lls_val *val,
		const struct lls_option *opt, char *result)
{
	char *line = NULL, *tmp = NULL;

	switch (opt->arg_type) {
	case LLS_INT32:
		xasprintf(&line, "%" PRId32, val->int32_val);
		break;
	case LLS_UINT32:
		xasprintf(&line, "%" PRIu32, val->uint32_val);
		break;
	case LLS_INT64:
		xasprintf(&line, "%" PRId64, val->int64_val);
		break;
	case LLS_UINT64:
		xasprintf(&line, "%" PRIu64, val->uint64_val);
		break;
	case LLS_STRING:
		{
		const char *s, *p;
		char *q;

		if (opt->values)
			s = lls_enum_string_val(val->uint32_val, opt);
		else {
			s = val->string_val;
			if (!s)
				return result;
		}
		line = malloc(2 * strlen(s) + 3);
		if (!line) {
			free(result);
			return NULL;
		}
		line[0] = '"';
		for (p = s, q = line + 1; *p; p++, q++) {
			if (*p == '\\' || *p == '\n' || *p == '\t' || *p == '"') {
				*q = '\\';
				q++;
			}
			*q = *p;
		}
		q[0] = '"';
		q[1] = '\0';
		break;
		}
	default:
		assert(0);
	}
	xasprintf(&tmp, "%s%s=%s\n", result? result : "", opt->name, line);
	free(line);
	free(result);
	return tmp;
}

char *lls_dump_parse_result(const struct lls_parse_result *lpr,
		const struct lls_command *cmd, bool non_default_only)
{
	int i;
	char *result = NULL;

	FOR_EACH_OPTION(i, cmd->options) {
		const struct lls_option *opt = cmd->options + i;
		struct lls_opt_result *lor = lpr->opt_result + i;
		bool given = lor->given;
		int j, n;

		if (!given && non_default_only)
			continue;
		if (opt->arg_info == LLS_NO_ARGUMENT) {
			char *tmp = NULL;
			if (!given)
				continue;
			xasprintf(&tmp, "%s%s\n", result? result : "",
				opt->name);
			free(result);
			result = tmp;
			continue;
		}
		n = num_vals_in_parse_result(cmd, i, lpr);
		for (j = 0; j < n; j++) {
			union lls_val *val = lor->value + j;
			if (non_default_only && is_default_val(val, opt))
				continue;
			result = append_opt_val(val, opt, result);
		}
	}
	if (!result) { /* empty dump */
		result = malloc(1);
		if (result)
			result[0] = '\0';
	}
	return result;
}