/********************************************************/

/*  ntapi: Native API core library                      */

/*  Copyright (C) 2013--2016  Z. Gilboa                 */

/*  Released under GPLv2 and GPLv3; see COPYING.NTAPI.  */

/********************************************************/

#include <psxtypes/psxtypes.h>

#include <ntapi/ntapi.h>

#include "ntapi_impl.h"

/**

 *  a simple facility for minimal programs or system libraries

 *  with no libc available at the time of invocation, as well

 *  as applications using the midipix free-standing development

 *  environment.

 *

 *  the approach taken by this module to the support of short

 *  and long options reflects the above constraint, namely

 *  the absence of a callable libc at the time of invocation;

 *  there is no intent for interfaces in this module to

 *  be POSIXLY correct or otherwise portable.  the sole

 *  purpose of all functions in this module is to serve

 *  internal or otherwise free-standing midipix applications,

 *  and their relevance otherwise is accordingly non-existent.

 *

 *  all options are encoded in utf-16; note, however, that

 *  short options may only use code points that are located

 *  in the basic multilingual plane.

 *

 *  option values are either required or not allowed altogether,

 *  and the first character of an option value may not be a hyphen.

 *  if you need the first character of an option value to be a

 *  hyphen, then make sure you escape it somehow (for instance by

 *  enclosing it in quotation marks).

 *

 *  a short option and its value must reside in two separate

 *  argv[] elements (in other words: -ooutput is illegal).

 *

 *  a long option and its value must reside in the same argv[]

 *  element and be separated by a single equal sign.

 *

 *  Examples of valid options and option values:

 *  --------------------------------------------

 *  -o

 *  -o value

 *  --long-option-with-no-value

 *  --long-option=value

**/

#define HYPHEN		0x2D

#define EQUAL_SIGN	0x3D

static __inline__ __fastcall int __is_bmp_code_point(uint16_t code_point)

{

	return ((code_point < 0xD800) || (code_point >= 0xE000));

}

static __inline__ __fastcall int __is_last_program_option(

	__in	nt_program_option *	option)

{

	return (!(option->short_name_code))

		&& (!(option->long_name))

		&& (!(option->long_name_hash));

}

static int __fastcall __is_short_option(wchar16_t * wch)

{

	return ((wch) && (*wch == HYPHEN)

		&& __is_bmp_code_point(*++wch)

		&& (*++wch == 0));

}

static int __fastcall __is_long_option(wchar16_t * wch)

{

	return ((wch) && (*wch == HYPHEN)

		&& (++wch) && (*wch == HYPHEN)

		&& (*++wch));

}

static int __fastcall __is_last_option_argument(wchar16_t * wch)

{

	return ((wch) && (*wch == HYPHEN)

		&& (*++wch == HYPHEN)

		&& (*++wch == 0));

}

static uint32_t __fastcall __compute_crc32_utf16_str(

	__in	const uint32_t *	crc32_table,

	__in	wchar16_t *		wch)

{

	uint32_t	crc32;

	unsigned char *	byte_buffer;

	/* crc32 hash... */

	crc32 = 0 ^ 0xFFFFFFFF;

	/* initialize byte_buffer */

	byte_buffer = (unsigned char *)wch;

	/* iterate */

	while (*byte_buffer) {

		/* two bytes at a time */

		crc32 = (crc32 >> 8) ^ crc32_table[(crc32 ^ *byte_buffer) & 0xFF];

		byte_buffer++;

		crc32 = (crc32 >> 8) ^ crc32_table[(crc32 ^ *byte_buffer) & 0xFF];

		byte_buffer++;

	}

	return crc32;

}

static uint32_t __fastcall __compute_crc32_long_option_name(

	__in	const uint32_t *	crc32_table,

	__in	wchar16_t *		wch_arg,

	__in	wchar16_t *		wch_termination)

{

	uint32_t	crc32;

	unsigned char *	byte_buffer;

	/* crc32 hash... */

	crc32 = 0 ^ 0xFFFFFFFF;

	/* initialize byte_buffer */

	byte_buffer = (unsigned char *)wch_arg;

	/* iterate */

	while ((uintptr_t)byte_buffer < (uintptr_t)wch_termination) {

		/* two bytes at a time */

		crc32 = (crc32 >> 8) ^ crc32_table[(crc32 ^ *byte_buffer) & 0xFF];

		byte_buffer++;

		crc32 = (crc32 >> 8) ^ crc32_table[(crc32 ^ *byte_buffer) & 0xFF];

		byte_buffer++;

	}

	return crc32;

}

static void __fastcall __init_cmd_option_meta_utf16(

	__in	nt_cmd_option_meta_utf16 *	cmd_opt_meta)

{

	cmd_opt_meta->short_name	= (wchar16_t *)0;

	cmd_opt_meta->short_name_code	= 0;

	cmd_opt_meta->long_name		= (wchar16_t *)0;

	cmd_opt_meta->long_name_hash	= 0;

	cmd_opt_meta->value		= (wchar16_t *)0;

	cmd_opt_meta->value_hash	= 0;

	cmd_opt_meta->argv_index	= 0;

	cmd_opt_meta->flags		= 0;

	return;

}

int32_t __stdcall __ntapi_tt_get_short_option_meta_utf16(

	__in	const uint32_t *		crc32_table,

	__in	wchar16_t			option_name,

	__in	wchar16_t *			argv[],

	__out	nt_cmd_option_meta_utf16 *	cmd_opt_meta)

{

	int		idx;

	wchar16_t *	wch;

	if (!crc32_table)

		return NT_STATUS_INVALID_PARAMETER_1;

	else if (!option_name)

		return NT_STATUS_INVALID_PARAMETER_2;

	else if (!argv)

		return NT_STATUS_INVALID_PARAMETER_3;

	/* initialize cmd_opt_meta  */

	__init_cmd_option_meta_utf16(cmd_opt_meta);

	/* step 1: attempt to find the short option in argv[] */

	idx = 0;

	while (argv[idx] && (!cmd_opt_meta->short_name_code)) {

		wch = argv[idx];

		/* is this our option? */

		if ((*wch == HYPHEN)

			&& (*++wch == option_name)

			&& (*++wch == 0)) {

			/* found it, get ready to hash the value */

			cmd_opt_meta->short_name_code = option_name;

			cmd_opt_meta->short_name = argv[idx];

			cmd_opt_meta->argv_index = idx;

		} else {

			idx++;

		}

	}

	/* if the next argument is also an option (or is null), just exit */

	idx++;

	if ((!argv[idx]) || (*argv[idx] == HYPHEN))

		return NT_STATUS_SUCCESS;

	/* step 2: hash the value */

	cmd_opt_meta->value = argv[idx];

	cmd_opt_meta->value_hash =

		__compute_crc32_utf16_str(

			crc32_table,

			argv[idx]);

	return NT_STATUS_SUCCESS;

}

int32_t __stdcall __ntapi_tt_get_long_option_meta_utf16(

	__in	const uint32_t *		crc32_table,

	__in	wchar16_t *			option_name,

	__in	uint32_t			option_name_hash __optional,

	__in	wchar16_t *			argv[],

	__out	nt_cmd_option_meta_utf16 *	cmd_opt_meta)

{

	/**

	 *  option_name must always include the two-hyphen prefix;

	 *  and the option value must be preceded by an equal sign.

	 *

	 *  the only valid long option forms in argv[] are therefore:

	 *  --long-option

	 *  --long-option=value

	**/

	int		idx;

	uint32_t	crc32;

	wchar16_t *	wch;

	/* validation */

	if (!crc32_table)

		return NT_STATUS_INVALID_PARAMETER_1;

	else if ((!option_name) && (!option_name_hash))

		return NT_STATUS_INVALID_PARAMETER;

	else if ((option_name) && (option_name_hash))

		return NT_STATUS_INVALID_PARAMETER_MIX;

	else if (!argv)

		return NT_STATUS_INVALID_PARAMETER_4;

	/* initialize cmd_opt_meta  */

	__init_cmd_option_meta_utf16(cmd_opt_meta);

	/* step 1: crc32 of the target option_name */

	if (option_name_hash)

		crc32 = option_name_hash;

	else

		option_name_hash =

			__compute_crc32_utf16_str(

				crc32_table,

				option_name);

	/* step 2: attempt to find the long option in argv[] */

	idx = 0;

	while (argv[idx] && (!cmd_opt_meta->value))  {

		wch = argv[idx];

		if (__is_long_option(wch)) {

			/* find the equal sign or null termination */

			while ((*wch) && (*wch != EQUAL_SIGN))

				wch++;

			crc32 = __compute_crc32_long_option_name(

				crc32_table,

				argv[idx],

				wch);

			if (crc32 == option_name_hash) {

				/* found it, get ready to hash the value */

				cmd_opt_meta->long_name_hash = option_name_hash;

				cmd_opt_meta->long_name	 = argv[idx];

				cmd_opt_meta->argv_index = idx;

				if (*wch)

					/* skip the equal sign */

					wch++;

				cmd_opt_meta->value = wch;

			} else

				idx++;

		}

	}

	if (cmd_opt_meta->value)

		cmd_opt_meta->value_hash =

			__compute_crc32_utf16_str(

				crc32_table,

				cmd_opt_meta->value);

	return NT_STATUS_SUCCESS;

}

int32_t __stdcall __ntapi_tt_validate_program_options(

	__in	const uint32_t *		crc32_table,

	__in	wchar16_t *			argv[],

	__in	nt_program_option *		options[],

	__in	nt_program_options_meta *	options_meta)

{

	int				idx;

	int				idx_arg;

	int				idx_option;

	int				idx_max;

	uint32_t			crc32;

	nt_program_option *		option;

	wchar16_t *			parg;

	wchar16_t *			pvalue;

	/* validation */

	if (!crc32_table)

		return NT_STATUS_INVALID_PARAMETER_1;

	else if (!argv)

		return NT_STATUS_INVALID_PARAMETER_2;

	else if (!options)

		return NT_STATUS_INVALID_PARAMETER_3;

	else if (!options_meta)

		return NT_STATUS_INVALID_PARAMETER_4;

	/* step 1: validate options[] hash the long option names */

	idx		= 0;

	idx_option	= 0;

	option		= options[0];

	pvalue  	= (wchar16_t *)0;

	while (!__is_last_program_option(option)) {

		if (option->short_name_code) {

			if (!(__is_bmp_code_point(option->short_name_code))) {

				options_meta->idx_invalid_short_name = idx;

				return NT_STATUS_INVALID_PARAMETER;

			}

		}

		if (option->long_name) {

			if (!(__is_long_option(option->long_name))) {

				options_meta->idx_invalid_long_name = idx;

				return NT_STATUS_INVALID_PARAMETER;

			}

			/* update the long name hash (unconditionally) */

			option->long_name_hash =

				__compute_crc32_utf16_str(

					crc32_table,

					option->long_name);

		}

		idx++;

		option++;

	}

	/* book keeping */

	idx_max = idx;

	/* step 2: validate argv[] */

	parg	= argv[0];

	idx_arg	= 0;

	while ((parg) && (!(__is_last_option_argument(parg)))) {

		if (__is_short_option(parg)) {

			idx = 0;

			idx_option = 0;

			while ((idx < idx_max) && (!idx_option)) {

				option = options[idx];

				if (*(parg+1) == option->short_name_code)

					idx_option = idx;

				else

					idx++;

			}

			if (idx == idx_max) {

				options_meta->idx_invalid_argument = idx_arg;

				return NT_STATUS_INVALID_PARAMETER;

			} else {

				/* get ready for the next element (or value) */

				parg++;

				idx_arg++;

				pvalue = parg;

			}

		} else if (__is_long_option(parg)) {

			idx = 0;

			idx_option = 0;

			/* find the equal sign or null termination */

			pvalue = parg;

			while ((*pvalue) && (*pvalue != EQUAL_SIGN))

				pvalue++;

			while ((idx < idx_max) && (!idx_option)) {

				option = options[idx];

				crc32  = __compute_crc32_long_option_name(

						crc32_table,

						parg,

						pvalue);

				if (crc32 == option->long_name_hash)

					idx_option = idx;

				else

					idx++;

			}

			if (idx == idx_max) {

				options_meta->idx_invalid_argument = idx_arg;

				return NT_STATUS_INVALID_PARAMETER;

			} else {

				if (*pvalue != EQUAL_SIGN)

					/* skip the equal sign */

					pvalue++;

				pvalue = (wchar16_t *)0;

			}

		}

		/* validate the occurrence */

		if (idx_option) {

			if (option->flags & NT_OPTION_ALLOWED_ONCE) {

				if (option->option_count) {

					options_meta->idx_invalid_argument

						= idx_arg;

					return NT_STATUS_INVALID_PARAMETER;

				} else {

					option->option_count++;

				}

			}

			if (option->flags & NT_OPTION_VALUE_REQUIRED) {

				if ((!(*pvalue)) || (*pvalue == HYPHEN)) {

					options_meta->idx_missing_option_value

						= idx_arg;

					return NT_STATUS_INVALID_PARAMETER;

				} else {

					option->value 	   = pvalue;

					option->value_hash =

						__compute_crc32_utf16_str(

							crc32_table,

							option->value);

				}

			}

		}

		parg++;

		idx_arg++;

	}

	return NT_STATUS_SUCCESS;

}