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

/*  ntapi: Native API core library                      */

/*  Copyright (C) 2013--2021  SysDeer Technologies, LLC */

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

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

#include <psxtypes/psxtypes.h>

#include <pemagine/pemagine.h>

#include <ntapi/nt_argv.h>

#include <ntapi/ntapi.h>

#include "ntapi_impl.h"

typedef struct ___two_bytes {

	unsigned char	low;

	unsigned char	high;

} __two_bytes;

typedef struct ___three_bytes {

	unsigned char	low;

	unsigned char	middle;

	unsigned char	high;

} __three_bytes;

static void __utf8_to_utf16_handler_1byte_or_null_termination(wchar16_t * dst, const unsigned char * ch)

{

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

	/* from: 0xxxxxxx          */

	/* to:   00000000 0xxxxxxx */

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

	*dst = *ch;

}

static void __utf8_to_utf16_handler_2bytes(wchar16_t * dst, const unsigned char * ch)

{

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

	/* from: 110yyyyy 10xxxxxx */

	/* to:   00000yyy yyxxxxxx */

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

	__two_bytes * src; /* big endian */

	src = (__two_bytes *)ch;

	/* yyyyy */

	*dst   = (src->low ^ 0xC0);

	*dst <<= 6;

	/* xxxxxx */

	*dst |= (src->high ^ 0x80);

}

static void __utf8_to_utf16_handler_3bytes(wchar16_t * dst, const unsigned char * ch)

{

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

	/* from: 1110zzzz 10yyyyyy 10xxxxxx */

	/* to:   zzzzyyyy yyxxxxxx          */

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

	__three_bytes *	src; /* big endian */

	wchar16_t	yyyyy;

	src = (__three_bytes *)ch;

	/* zzzz */

	*dst   = (src->low ^ 0xE0);

	*dst <<= 12;

	/* yyyyy */

	yyyyy   = (src->middle ^ 0x80);

	yyyyy <<= 6;

	*dst |= yyyyy;

	/* xxxxxx */

	*dst |= (src->high ^ 0x80);

}

static void __utf8_to_utf16_handler_4bytes(wchar16_t * dst, const unsigned char * ch)

{

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

	/* from: 11110uuu  10uuzzzz  10yyyyyy  10xxxxxx  */

	/* to:   110110ww  wwzzzzyy  110111yy  yyxxxxxx  */

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

	__two_bytes *		src_low;	/* big endian */

	__two_bytes *		src_high;	/* big endian */

	wchar16_t *		dst_lead;

	wchar16_t *		dst_trail;

	wchar16_t		wwww;

	wchar16_t		lead;

	wchar16_t		trail;

	unsigned char		ulow;

	unsigned char		uhigh;

	unsigned char		yy;

	unsigned char		yyyy;

	unsigned char		zzzz;

	dst_lead = dst_trail = (wchar16_t *)dst;

	dst_trail++;

	src_low	= src_high = (__two_bytes *)ch;

	src_high++;

	/* uuuuu */

	ulow  = src_low->low  ^ 0xF0;

	uhigh = src_low->high ^ 0x80;

	ulow  <<= 2;

	uhigh >>= 4;

	/* wwww */

	wwww   = (ulow | uhigh) - 1;

	wwww <<= 6;

	/* 110110ww wwzzzzyy */

	yy     = src_high->low ^ 0x80;

	yy   >>= 4;

	zzzz   = src_low->high;

	zzzz <<= 4;

	zzzz >>= 2;

	lead   = 0xD800;

	lead  |= wwww;

	lead  |= zzzz;

	lead  |= yy;

	/* 110111yy  yyxxxxxx */

	yyyy   = src_high->low << 4;

	trail  = yyyy << 2;

	trail |= src_high->high ^ 0x80;

	trail |= 0xDC00;

	/* write */

	*dst_lead  = lead;

	*dst_trail = trail;

}

int32_t __stdcall __ntapi_tt_array_copy_utf8(

	__out	int *			argc,

	__in	const char **		argv,

	__in	const char **		envp,

	__in	const char *		interp,

	__in	const char *		optarg,

	__in	const char *		script,

	__in	void *			base,

	__out	void *			buffer,

	__in	size_t			buflen,

	__out	size_t *		blklen)

{

	const char **	parg;

	const char *	arg;

	const char *	mark;

	char *		ch;

	ptrdiff_t	diff;

	ptrdiff_t	ptrs;

	size_t		needed;

	const char *	dummy[2] = {0,0};

	/* fallback */

	argv = argv ? argv : dummy;

	envp = envp ? envp : dummy;

	/* ptrs, needed */

	ptrs   = 0;

	needed = 0;

	/* interpr */

	if (interp) {

		ptrs++;

		needed += sizeof(char *)

			+ __ntapi->tt_string_null_offset_multibyte(interp)

			+ sizeof(char);

	}

	/* optarg */

	if (optarg) {

		ptrs++;

		needed += sizeof(char *)

			+ __ntapi->tt_string_null_offset_multibyte(optarg)

			+ sizeof(char);

	}

	/* script / argv[0] */

	if ((mark = script ? script : argv[0])) {

		ptrs++;

		needed += sizeof(char *)

			+ __ntapi->tt_string_null_offset_multibyte(mark)

			+ sizeof(char);

	}

	/* argv */

	for (parg=&argv[1]; *parg; parg++)

		needed += sizeof(char *)

			+ __ntapi->tt_string_null_offset_multibyte(*parg)

			+ sizeof(char);

	ptrs += (parg - &argv[1]);

	*argc = (int)ptrs;

	/* envp */

	for (parg=envp; *parg; parg++)

		needed += sizeof(char *)

			+ __ntapi->tt_string_null_offset_multibyte(*parg)

			+ sizeof(char);

	ptrs += (parg - envp);

	ptrs   += 2;

	needed += 2*sizeof(char *);

	blklen  = blklen ? blklen : &needed;

	*blklen = needed;

	if (buflen < needed)

		return NT_STATUS_BUFFER_TOO_SMALL;

	/* init */

	parg = (const char **)buffer;

	ch   = (char *)(parg+ptrs);

	diff = (ptrdiff_t)base;

	/* interp */

	if (interp) {

		*parg++ = ch-diff;

		for (arg=interp; *arg; arg++,ch++)

			*ch = *arg;

		*ch++ = '\0';

	}

	/* optarg */

	if (optarg) {

		*parg++ = ch-diff;

		for (arg=optarg; *arg; arg++,ch++)

			*ch = *arg;

		*ch++ = '\0';

	}

	/* script / argv[0] */

	if ((mark = script ? script : argv[0])) {

		*parg++ = ch-diff;

		for (arg=mark; *arg; arg++,ch++)

			*ch = *arg;

		*ch++ = '\0';

	}

	/* argv */

	for (++argv; *argv; argv++) {

		*parg++=ch-diff;

		for (arg=*argv; *arg; arg++,ch++)

			*ch = *arg;

		*ch++ = '\0';

	}

	*parg++ = 0;

	/* envp */

	for (; *envp; envp++) {

		*parg++=ch-diff;

		for (arg=*envp; *arg; arg++,ch++)

			*ch = *arg;

		*ch++ = '\0';

	}

	*parg++ = 0;

	return NT_STATUS_SUCCESS;

}

static void (*__utf8_to_utf16_handlers[5])(wchar16_t *, const unsigned char *) = {

	0,

	__utf8_to_utf16_handler_1byte_or_null_termination,

	__utf8_to_utf16_handler_2bytes,

	__utf8_to_utf16_handler_3bytes,

	__utf8_to_utf16_handler_4bytes};

int32_t __stdcall __ntapi_tt_array_convert_utf8_to_utf16(

	__in		char **		arrv,

	__out		wchar16_t **	warrv,

	__out		void *		base,

	__out		wchar16_t *	buffer,

	__in		size_t		buffer_len,

	__out		size_t *	bytes_written)

{

	wchar16_t *	ubound;

	wchar16_t *	wch;

	ptrdiff_t	diff;

	ptrdiff_t	wdiff;

	char *		ch;

	const uint8_t *	utf8;

	uint8_t		byte_count;

	if ((uintptr_t)base % sizeof(wchar16_t))

		return NT_STATUS_INVALID_PARAMETER_3;

	wch   = buffer;

	diff  = (ptrdiff_t)base;

	wdiff = (ptrdiff_t)base / sizeof(wchar16_t);

	ubound  = buffer;

	ubound += buffer_len / sizeof(wchar16_t);

	ubound--;

	ubound--;

	ubound--;

	for (; arrv && *arrv; arrv++,warrv++) {

		*warrv = wch - wdiff;

		ch     = *arrv + diff;

		/* ubound already accounts for null termination, see above */

		for (; *ch && (wch

			utf8       = (const uint8_t *)ch;

			byte_count = 0;

			/* try one byte */

			if (utf8[0] <= 0x7F)

				byte_count = 1;

			/* try two bytes */

			else if ((++ch)

					&& (utf8[0] >= 0xC2) && (utf8[0] <= 0xDF)

					&& (utf8[1] >= 0x80) && (utf8[1] <= 0xBF))

				byte_count = 2;

			/* try three bytes */

			else if ((++ch)

					&& (utf8[0] == 0xE0)

					&& (utf8[1] >= 0xA0) && (utf8[1] <= 0xBF)

					&& (utf8[2] >= 0x80) && (utf8[2] <= 0xBF))

				byte_count = 3;

			else if (

					(utf8[0] >= 0xE1) && (utf8[0] <= 0xEC)

					&& (utf8[1] >= 0x80) && (utf8[1] <= 0xBF)

					&& (utf8[2] >= 0x80) && (utf8[2] <= 0xBF))

				byte_count = 3;

			else if (

					(utf8[0] == 0xED)

					&& (utf8[1] >= 0x80) && (utf8[1] <= 0x9F)

					&& (utf8[2] >= 0x80) && (utf8[2] <= 0xBF))

				byte_count = 3;

			else if (

					(utf8[0] >= 0xEE) && (utf8[0] <= 0xEF)

					&& (utf8[1] >= 0x80) && (utf8[1] <= 0xBF)

					&& (utf8[2] >= 0x80) && (utf8[2] <= 0xBF))

				byte_count = 3;

			/* try four bytes */

			else if ((++ch)

					&& (utf8[0] == 0xF0)

					&& (utf8[1] >= 0x90) && (utf8[1] <= 0xBF)

					&& (utf8[2] >= 0x80) && (utf8[2] <= 0xBF)

					&& (utf8[3] >= 0x80) && (utf8[3] <= 0xBF))

				byte_count = 4;

			else if (

					(utf8[0] >= 0xF1) && (utf8[0] <= 0xF3)

					&& (utf8[1] >= 0x80) && (utf8[1] <= 0xBF)

					&& (utf8[2] >= 0x80) && (utf8[2] <= 0xBF)

					&& (utf8[3] >= 0x80) && (utf8[3] <= 0xBF))

				byte_count = 4;

			else if (

					(utf8[0] == 0xF4)

					&& (utf8[1] >= 0x80) && (utf8[1] <= 0x8F)

					&& (utf8[2] >= 0x80) && (utf8[2] <= 0xBF)

					&& (utf8[3] >= 0x80) && (utf8[3] <= 0xBF))

				byte_count = 4;

			if (byte_count) {

				__utf8_to_utf16_handlers[byte_count](wch,utf8);

				wch = &wch[byte_count >> 3];

				wch++;

			} else {

				return NT_STATUS_ILLEGAL_CHARACTER;

			}

		}

		*wch++ = 0;

	}

	*wch++ = 0;

	*warrv = 0;

	*bytes_written = sizeof(wchar16_t) * (wch - buffer);

	return NT_STATUS_SUCCESS;

}