/*
** utf8.cpp
** UTF-8 utilities
**
**---------------------------------------------------------------------------
** Copyright 2019 Christoph Oelckers
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
**    notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
**    notice, this list of conditions and the following disclaimer in the
**    documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
**    derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/
#include <stdint.h>
#include "tarray.h"
#include "utf8.h"


//==========================================================================
//
//
//
//==========================================================================

int utf8_encode(int32_t codepoint, uint8_t *buffer, int *size)
{
	if (codepoint < 0)
		return -1;
	else if (codepoint < 0x80)
	{
		buffer[0] = (char)codepoint;
		*size = 1;
	}
	else if (codepoint < 0x800)
	{
		buffer[0] = 0xC0 + ((codepoint & 0x7C0) >> 6);
		buffer[1] = 0x80 + ((codepoint & 0x03F));
		*size = 2;
	}
	else if (codepoint < 0x10000)
	{
		buffer[0] = 0xE0 + ((codepoint & 0xF000) >> 12);
		buffer[1] = 0x80 + ((codepoint & 0x0FC0) >> 6);
		buffer[2] = 0x80 + ((codepoint & 0x003F));
		*size = 3;
	}
	else if (codepoint <= 0x10FFFF)
	{
		buffer[0] = 0xF0 + ((codepoint & 0x1C0000) >> 18);
		buffer[1] = 0x80 + ((codepoint & 0x03F000) >> 12);
		buffer[2] = 0x80 + ((codepoint & 0x000FC0) >> 6);
		buffer[3] = 0x80 + ((codepoint & 0x00003F));
		*size = 4;
	}
	else
		return -1;

	return 0;
}

//==========================================================================
//
//
//
//==========================================================================

int utf8_decode(const uint8_t *src, int *size) 
{
	int c = src[0];
	int r;

	*size = 1;
	if ((c & 0x80) == 0)
	{
		return c;
	}

	int c1 = src[1];
	if (c1 < 0x80 || c1 >= 0xc0) return -1;
	c1 &= 0x3f;

	if ((c & 0xE0) == 0xC0) 
	{
		r = ((c & 0x1F) << 6) | c1;
		if (r >= 128) 
		{
			*size = 2;
			return r;
		}
		return -1;
	}

	int c2 = src[2];
	if (c2 < 0x80 || c2 >= 0xc0) return -1;
	c2 &= 0x3f;

	if ((c & 0xF0) == 0xE0) 
	{
		r = ((c & 0x0F) << 12) | (c1 << 6) | c2;
		if (r >= 2048 && (r < 55296 || r > 57343)) 
		{
			*size = 3;
			return r;
		}
		return -1;
	}

	int c3 = src[3];
	if (c3 < 0x80 || c1 >= 0xc0) return -1;
	c3 &= 0x3f;

	if ((c & 0xF8) == 0xF0) 
	{
		r = ((c & 0x07) << 18) | (c1 << 12) | (c2 << 6) | c3;
		if (r >= 65536 && r <= 1114111) 
		{
			*size = 4;
			return r;
		}
	}
	return -1;
}

//==========================================================================
//
// Unicode mapping for the 0x80-0x9f range of the Windows 1252 code page
//
//==========================================================================

uint16_t win1252map[] = {
	0x20AC,
	0x81  ,
	0x201A,
	0x0192,
	0x201E,
	0x2026,
	0x2020,
	0x2021,
	0x02C6,
	0x2030,
	0x0160,
	0x2039,
	0x0152,
	0x8d  ,
	0x017D,
	0x8f  ,
	0x90  ,
	0x2018,
	0x2019,
	0x201C,
	0x201D,
	0x2022,
	0x2013,
	0x2014,
	0x02DC,
	0x2122,
	0x0161,
	0x203A,
	0x0153,
	0x9d  ,
	0x017E,
	0x0178,
};

//==========================================================================
//
// reads one character from the string.
// This can handle both ISO 8859-1/Windows-1252 and UTF-8, as well as mixed strings
// between both encodings, which may happen if inconsistent encoding is 
// used between different files in a mod.
//
//==========================================================================

int GetCharFromString(const uint8_t *&string)
{
	int z;

	z = *string;

	if (z < 192)
	{
		string++;

		// Handle Windows 1252 characters
		if (z >= 128 && z < 160)
		{
			return win1252map[z - 128];
		}
		return z;
	}
	else 
	{
		int size = 0;
		auto chr = utf8_decode(string, &size);
		if (chr >= 0)
		{
			string += size;
			return chr;
		}
		string++;
		return z;
	}
}

//==========================================================================
//
// convert a potentially mixed-encoded string to pure UTF-8
// this returns a pointer to a static buffer, 
// assuming that its caller will immediately process the result. 
//
//==========================================================================

static TArray<char> UTF8String;

const char *MakeUTF8(const char *outline, int *numchars)
{
	UTF8String.Clear();
	const uint8_t *in = (const uint8_t*)outline;

	if (numchars) *numchars = 0;
	while (int chr = GetCharFromString(in))
	{
		int size = 0;
		uint8_t encode[4];
		if (!utf8_encode(chr, encode, &size))
		{
			for (int i = 0; i < size; i++)
			{
				UTF8String.Push(encode[i]);
			}
		}
		if (numchars) (*numchars)++;
	}
	UTF8String.Push(0);
	return UTF8String.Data();
}

const char *MakeUTF8(int codepoint, int *psize)
{
	int size = 0;
	UTF8String.Resize(5);
	utf8_encode(codepoint, (uint8_t*)UTF8String.Data(), &size);
	UTF8String[size] = 0;
	if (psize) *psize = size;
	return UTF8String.Data();
}


//==========================================================================
//
// Returns a character without an accent mark (or one with a similar looking accent in some cases where direct support is unlikely.)
//
//==========================================================================

int stripaccent(int code)
{
	if (code < 0x8a)
		return code;
	if (code < 0x100)
	{
		if (code == 0x8a)	// Latin capital letter S with caron
			return 'S';
		if (code == 0x8e)	// Latin capital letter Z with caron
			return 'Z';
		if (code == 0x9a)	// Latin small letter S with caron
			return 's';
		if (code == 0x9e)	// Latin small letter Z with caron
			return 'z';
		if (code == 0x9f)	// Latin capital letter Y with diaeresis
			return 'Y';
		if (code == 0xab || code == 0xbb) return '"';	// typographic quotation marks.
		if (code == 0xff)	// Latin small letter Y with diaeresis
			return 'y';
		// Every other accented character has the high two bits set.
		if ((code & 0xC0) == 0)
			return code;
		// Make lowercase characters uppercase so there are half as many tests.
		int acode = code & 0xDF;
		if (acode >= 0xC0 && acode <= 0xC5)		// A with accents
			return 'A' + (code & 0x20);
		if (acode == 0xC7)						// Cedilla
			return 'C' + (acode & 0x20);
		if (acode >= 0xC8 && acode <= 0xCB)		// E with accents
			return 'E' + (code & 0x20);
		if (acode >= 0xCC && acode <= 0xCF)		// I with accents
			return 'I' + (code & 0x20);
		if (acode == 0xD0)						// Eth
			return 'D' + (code & 0x20);
		if (acode == 0xD1)						// N with tilde
			return 'N' + (code & 0x20);
		if ((acode >= 0xD2 && acode <= 0xD6) ||	// O with accents
			acode == 0xD8)						// O with stroke
			return 'O' + (code & 0x20);
		if (acode >= 0xD9 && acode <= 0xDC)		// U with accents
			return 'U' + (code & 0x20);
		if (acode == 0xDD)						// Y with accute
			return 'Y' + (code & 0x20);
		if (acode == 0xDE)						// Thorn
			return 'P' + (code & 0x20);			// well, it sort of looks like a 'P'
	}
	else if (code >= 0x100 && code < 0x180)
	{
		// For the double-accented Hungarian letters it makes more sense to first map them to the very similar looking Umlauts.
		// (And screw the crappy specs that do not allow UTF-8 multibyte character literals here.)
		if (code == 0x150) code = 0xd6;
		else if (code == 0x151) code = 0xf6;
		else if (code == 0x170) code = 0xdc;
		else if (code == 0x171) code = 0xfc;
		else
		{
			static const char accentless[] = "AaAaAaCcCcCcCcDdDdEeEeEeEeEeGgGgGgGgHhHhIiIiIiIiIiIiJjKkkLlLlLlLlLlNnNnNnnNnOoOoOoOoRrRrRrSsSsSsSsTtTtTtUuUuUuUuUuUuWwYyYZzZzZzs";
			return accentless[code - 0x100];
		}
	}
	else if (code >= 0x1fc && code < 0x218)
	{
		// 0x200-0x217 are irrelevant but easy to map to other characters more likely to exist.
		static const uint16_t u200map[] = {0xc6, 0xe6, 0xd8, 0xf8, 0xc4, 0xe4, 0xc2, 0xe2, 0xcb, 0xeb, 0xca, 0xea, 0xcf, 0xef, 0xce, 0xee, 0xd6, 0xf6, 0xd4, 0xe4, 'R', 'r', 'R', 'r', 0xdc, 0xfc, 0xdb, 0xfb};
		return u200map[code - 0x1fc];
	}
	return getAlternative(code);
}

//==========================================================================
//
// Return replacement characters that should not make font completeness tests fail.
//
//==========================================================================

int getAlternative(int code)
{
	switch (code)
	{
		default:
			return code;

		case '{': return '(';
		case '}': return ')';
		case 0x17f:	return 's';	// The 'long s' can be safely remapped to the regular variant, not that this gets used in any real text...
		case 0x218:	return 0x15e; // Romanian S with comma below may get remapped to S with cedilla.
		case 0x219:	return 0x15f;
		case 0x21a:	return 0x162; // Romanian T with comma below may get remapped to T with cedilla.
		case 0x21b:	return 0x163;
		case 0x386:	return 0x391; // Greek characters with accents must map to their base form due to the "no accents in allcaps " rule.
		case 0x388:	return 0x395;
		case 0x389:	return 0x397;
		case 0x38a: return 0x399;
		case 0x38c:	return 0x39f;
		case 0x3a0:	return 0x41f;
		case 0x38e:	return 0x3a5;
		case 0x38f:	return 0x3a9;
		case 0x391: return 'A';// Greek characters with equivalents in either Latin or Cyrillic. This is only suitable for uppercase fonts!
		case 0x392:	return 'B';
		case 0x393:	return 0x413;
		case 0x395:	return 'E';
		case 0x396: return 'Z';
		case 0x397:	return 'H';
		case 0x399:	return 'I';
		case 0x39a:	return 'K';
		case 0x39c:	return 'M';
		case 0x39d:	return 'N';
		case 0x39f:	return 'O';
		case 0x3a1:	return 'P';
		case 0x3a4:	return 'T';
		case 0x3a5:	return 'Y';
		case 0x3a6:	return 0x424;
		case 0x3a7:	return 'X';
		case 0x3aa:	return 0xcf;
		case 0x3ab:	return 0x178;
		case 0x3bf:	return 'o'; // the Omicron is the only small Greek character that's easily mappable to a Latin equivalent. :(
		case 0x3c2:	return 0x3c3; // Lowercase Sigma character in Greek, which changes depending on its positioning in a word; if the font is uppercase only or features a smallcaps style, the second variant of the letter will remain unused
		case 0x390:	return 0x3ca; // For smallcaps fonts the small accented Greek characters remap to the unaccented versions.
		case 0x3ac:	return 0x3b1;
		case 0x3ad:	return 0x3b5;
		case 0x3ae:	return 0x3b7;
		case 0x3af:	return 0x3b9;
		case 0x3b0:	return 0x3cb;
		case 0x3cc:	return 0x3bf;
		case 0x3cd:	return 0x3c5;
		case 0x3ce:	return 0x3c9;
		case 0x400:	return 0xc8; // Cyrillic characters with equivalents in the Latin alphabet.
		case 0x401:	return 0xcb;
		case 0x405:	return 'S';
		case 0x406:	return 'I';
		case 0x407: return 0xcf;
		case 0x408:	return 'J';
		case 0x410: return 'A';
		case 0x412: return 'B';
		case 0x415: return 'E';
		case 0x41a: return 'K';
		case 0x41c: return 'M';
		case 0x41d: return 'H';
		case 0x41e: return 'O';
		case 0x420: return 'P';
		case 0x421: return 'C';
		case 0x422: return 'T';
		case 0x425: return 'X';
		case 0x430: return 'a';
		case 0x435: return 'e';
		case 0x43e: return 'o';
		case 0x440: return 'p';
		case 0x441: return 'c';
		case 0x445: return 'x';
		case 0x450: return 0xe8;
		case 0x451:	return 0xeb;
		case 0x455:	return 's';
		case 0x456:	return 'i';
		case 0x457:	return 0xef;
		case 0x458:	return 'j';
	}
}

//==========================================================================
//
// Unicode-aware upper/lowercase conversion
// The only characters not being handled by this are the Turkish I's
// because those are language specific.
//
//==========================================================================

uint16_t lowerforupper[65536];
uint16_t upperforlower[65536];
bool islowermap[65536];
bool isuppermap[65536];

// This is a supposedly complete mapping of all lower <-> upper pairs. Most will most likely never be needed by Doom but this way there won't be any future surprises
static const uint16_t loweruppercase[] = {
0x0061,0x0041,
0x0062,0x0042,
0x0063,0x0043,
0x0064,0x0044,
0x0065,0x0045,
0x0066,0x0046,
0x0067,0x0047,
0x0068,0x0048,
0x0069,0x0049,
0x006A,0x004A,
0x006B,0x004B,
0x006C,0x004C,
0x006D,0x004D,
0x006E,0x004E,
0x006F,0x004F,
0x0070,0x0050,
0x0071,0x0051,
0x0072,0x0052,
0x0073,0x0053,
0x0074,0x0054,
0x0075,0x0055,
0x0076,0x0056,
0x0077,0x0057,
0x0078,0x0058,
0x0079,0x0059,
0x007A,0x005A,
0x00DF,0x1E9E,
0x00E0,0x00C0,
0x00E1,0x00C1,
0x00E2,0x00C2,
0x00E3,0x00C3,
0x00E4,0x00C4,
0x00E5,0x00C5,
0x00E6,0x00C6,
0x00E7,0x00C7,
0x00E8,0x00C8,
0x00E9,0x00C9,
0x00EA,0x00CA,
0x00EB,0x00CB,
0x00EC,0x00CC,
0x00ED,0x00CD,
0x00EE,0x00CE,
0x00EF,0x00CF,
0x00F0,0x00D0,
0x00F1,0x00D1,
0x00F2,0x00D2,
0x00F3,0x00D3,
0x00F4,0x00D4,
0x00F5,0x00D5,
0x00F6,0x00D6,
0x00F8,0x00D8,
0x00F9,0x00D9,
0x00FA,0x00DA,
0x00FB,0x00DB,
0x00FC,0x00DC,
0x00FD,0x00DD,
0x00FE,0x00DE,
0x00FF,0x0178,
0x0101,0x0100,
0x0103,0x0102,
0x0105,0x0104,
0x0107,0x0106,
0x0109,0x0108,
0x010B,0x010A,
0x010D,0x010C,
0x010F,0x010E,
0x0111,0x0110,
0x0113,0x0112,
0x0115,0x0114,
0x0117,0x0116,
0x0119,0x0118,
0x011B,0x011A,
0x011D,0x011C,
0x011F,0x011E,
0x0121,0x0120,
0x0123,0x0122,
0x0125,0x0124,
0x0127,0x0126,
0x0129,0x0128,
0x012B,0x012A,
0x012D,0x012C,
0x012F,0x012E,
0x0133,0x0132,
0x0135,0x0134,
0x0137,0x0136,
0x013A,0x0139,
0x013C,0x013B,
0x013E,0x013D,
0x0140,0x013F,
0x0142,0x0141,
0x0144,0x0143,
0x0146,0x0145,
0x0148,0x0147,
0x014B,0x014A,
0x014D,0x014C,
0x014F,0x014E,
0x0151,0x0150,
0x0153,0x0152,
0x0155,0x0154,
0x0157,0x0156,
0x0159,0x0158,
0x015B,0x015A,
0x015D,0x015C,
0x015F,0x015E,
0x0161,0x0160,
0x0163,0x0162,
0x0165,0x0164,
0x0167,0x0166,
0x0169,0x0168,
0x016B,0x016A,
0x016D,0x016C,
0x016F,0x016E,
0x0171,0x0170,
0x0173,0x0172,
0x0175,0x0174,
0x0177,0x0176,
0x017A,0x0179,
0x017C,0x017B,
0x017E,0x017D,
0x0183,0x0182,
0x0185,0x0184,
0x0188,0x0187,
0x018C,0x018B,
0x0192,0x0191,
0x0199,0x0198,
0x01A1,0x01A0,
0x01A3,0x01A2,
0x01A5,0x01A4,
0x01A8,0x01A7,
0x01AD,0x01AC,
0x01B0,0x01AF,
0x01B4,0x01B3,
0x01B6,0x01B5,
0x01B9,0x01B8,
0x01BD,0x01BC,
0x01C6,0x01C4,
0x01C9,0x01C7,
0x01CC,0x01CA,
0x01CE,0x01CD,
0x01D0,0x01CF,
0x01D2,0x01D1,
0x01D4,0x01D3,
0x01D6,0x01D5,
0x01D8,0x01D7,
0x01DA,0x01D9,
0x01DC,0x01DB,
0x01DF,0x01DE,
0x01E1,0x01E0,
0x01E3,0x01E2,
0x01E5,0x01E4,
0x01E7,0x01E6,
0x01E9,0x01E8,
0x01EB,0x01EA,
0x01ED,0x01EC,
0x01EF,0x01EE,
0x01F3,0x01F1,
0x01F5,0x01F4,
0x01FB,0x01FA,
0x01FD,0x01FC,
0x01FF,0x01FE,
0x0201,0x0200,
0x0203,0x0202,
0x0205,0x0204,
0x0207,0x0206,
0x0209,0x0208,
0x020B,0x020A,
0x020D,0x020C,
0x020F,0x020E,
0x0211,0x0210,
0x0213,0x0212,
0x0215,0x0214,
0x0217,0x0216,
0x0253,0x0181,
0x0254,0x0186,
0x0257,0x018A,
0x0258,0x018E,
0x0259,0x018F,
0x025B,0x0190,
0x0260,0x0193,
0x0263,0x0194,
0x0268,0x0197,
0x0269,0x0196,
0x026F,0x019C,
0x0272,0x019D,
0x0275,0x019F,
0x0283,0x01A9,
0x0288,0x01AE,
0x028A,0x01B1,
0x028B,0x01B2,
0x0292,0x01B7,
0x03AC,0x0386,
0x03AD,0x0388,
0x03AE,0x0389,
0x03AF,0x038A,
0x03B1,0x0391,
0x03B2,0x0392,
0x03B3,0x0393,
0x03B4,0x0394,
0x03B5,0x0395,
0x03B6,0x0396,
0x03B7,0x0397,
0x03B8,0x0398,
0x03B9,0x0399,
0x03BA,0x039A,
0x03BB,0x039B,
0x03BC,0x039C,
0x03BD,0x039D,
0x03BE,0x039E,
0x03BF,0x039F,
0x03C0,0x03A0,
0x03C1,0x03A1,
0x03C3,0x03A3,
0x03C4,0x03A4,
0x03C5,0x03A5,
0x03C6,0x03A6,
0x03C7,0x03A7,
0x03C8,0x03A8,
0x03C9,0x03A9,
0x03CA,0x03AA,
0x03CB,0x03AB,
0x03CC,0x038C,
0x03CD,0x038E,
0x03CE,0x038F,
0x03E3,0x03E2,
0x03E5,0x03E4,
0x03E7,0x03E6,
0x03E9,0x03E8,
0x03EB,0x03EA,
0x03ED,0x03EC,
0x03EF,0x03EE,
0x0430,0x0410,
0x0431,0x0411,
0x0432,0x0412,
0x0433,0x0413,
0x0434,0x0414,
0x0435,0x0415,
0x0436,0x0416,
0x0437,0x0417,
0x0438,0x0418,
0x0439,0x0419,
0x043A,0x041A,
0x043B,0x041B,
0x043C,0x041C,
0x043D,0x041D,
0x043E,0x041E,
0x043F,0x041F,
0x0440,0x0420,
0x0441,0x0421,
0x0442,0x0422,
0x0443,0x0423,
0x0444,0x0424,
0x0445,0x0425,
0x0446,0x0426,
0x0447,0x0427,
0x0448,0x0428,
0x0449,0x0429,
0x044A,0x042A,
0x044B,0x042B,
0x044C,0x042C,
0x044D,0x042D,
0x044E,0x042E,
0x044F,0x042F,
0x0451,0x0401,
0x0452,0x0402,
0x0453,0x0403,
0x0454,0x0404,
0x0455,0x0405,
0x0456,0x0406,
0x0457,0x0407,
0x0458,0x0408,
0x0459,0x0409,
0x045A,0x040A,
0x045B,0x040B,
0x045C,0x040C,
0x045E,0x040E,
0x045F,0x040F,
0x0461,0x0460,
0x0463,0x0462,
0x0465,0x0464,
0x0467,0x0466,
0x0469,0x0468,
0x046B,0x046A,
0x046D,0x046C,
0x046F,0x046E,
0x0471,0x0470,
0x0473,0x0472,
0x0475,0x0474,
0x0477,0x0476,
0x0479,0x0478,
0x047B,0x047A,
0x047D,0x047C,
0x047F,0x047E,
0x0481,0x0480,
0x0491,0x0490,
0x0493,0x0492,
0x0495,0x0494,
0x0497,0x0496,
0x0499,0x0498,
0x049B,0x049A,
0x049D,0x049C,
0x049F,0x049E,
0x04A1,0x04A0,
0x04A3,0x04A2,
0x04A5,0x04A4,
0x04A7,0x04A6,
0x04A9,0x04A8,
0x04AB,0x04AA,
0x04AD,0x04AC,
0x04AF,0x04AE,
0x04B1,0x04B0,
0x04B3,0x04B2,
0x04B5,0x04B4,
0x04B7,0x04B6,
0x04B9,0x04B8,
0x04BB,0x04BA,
0x04BD,0x04BC,
0x04BF,0x04BE,
0x04C2,0x04C1,
0x04C4,0x04C3,
0x04C8,0x04C7,
0x04CC,0x04CB,
0x04D1,0x04D0,
0x04D3,0x04D2,
0x04D5,0x04D4,
0x04D7,0x04D6,
0x04D9,0x04D8,
0x04DB,0x04DA,
0x04DD,0x04DC,
0x04DF,0x04DE,
0x04E1,0x04E0,
0x04E3,0x04E2,
0x04E5,0x04E4,
0x04E7,0x04E6,
0x04E9,0x04E8,
0x04EB,0x04EA,
0x04EF,0x04EE,
0x04F1,0x04F0,
0x04F3,0x04F2,
0x04F5,0x04F4,
0x04F9,0x04F8,
0x0561,0x0531,
0x0562,0x0532,
0x0563,0x0533,
0x0564,0x0534,
0x0565,0x0535,
0x0566,0x0536,
0x0567,0x0537,
0x0568,0x0538,
0x0569,0x0539,
0x056A,0x053A,
0x056B,0x053B,
0x056C,0x053C,
0x056D,0x053D,
0x056E,0x053E,
0x056F,0x053F,
0x0570,0x0540,
0x0571,0x0541,
0x0572,0x0542,
0x0573,0x0543,
0x0574,0x0544,
0x0575,0x0545,
0x0576,0x0546,
0x0577,0x0547,
0x0578,0x0548,
0x0579,0x0549,
0x057A,0x054A,
0x057B,0x054B,
0x057C,0x054C,
0x057D,0x054D,
0x057E,0x054E,
0x057F,0x054F,
0x0580,0x0550,
0x0581,0x0551,
0x0582,0x0552,
0x0583,0x0553,
0x0584,0x0554,
0x0585,0x0555,
0x0586,0x0556,
0x10D0,0x10A0,
0x10D1,0x10A1,
0x10D2,0x10A2,
0x10D3,0x10A3,
0x10D4,0x10A4,
0x10D5,0x10A5,
0x10D6,0x10A6,
0x10D7,0x10A7,
0x10D8,0x10A8,
0x10D9,0x10A9,
0x10DA,0x10AA,
0x10DB,0x10AB,
0x10DC,0x10AC,
0x10DD,0x10AD,
0x10DE,0x10AE,
0x10DF,0x10AF,
0x10E0,0x10B0,
0x10E1,0x10B1,
0x10E2,0x10B2,
0x10E3,0x10B3,
0x10E4,0x10B4,
0x10E5,0x10B5,
0x10E6,0x10B6,
0x10E7,0x10B7,
0x10E8,0x10B8,
0x10E9,0x10B9,
0x10EA,0x10BA,
0x10EB,0x10BB,
0x10EC,0x10BC,
0x10ED,0x10BD,
0x10EE,0x10BE,
0x10EF,0x10BF,
0x10F0,0x10C0,
0x10F1,0x10C1,
0x10F2,0x10C2,
0x10F3,0x10C3,
0x10F4,0x10C4,
0x10F5,0x10C5,
0x1E01,0x1E00,
0x1E03,0x1E02,
0x1E05,0x1E04,
0x1E07,0x1E06,
0x1E09,0x1E08,
0x1E0B,0x1E0A,
0x1E0D,0x1E0C,
0x1E0F,0x1E0E,
0x1E11,0x1E10,
0x1E13,0x1E12,
0x1E15,0x1E14,
0x1E17,0x1E16,
0x1E19,0x1E18,
0x1E1B,0x1E1A,
0x1E1D,0x1E1C,
0x1E1F,0x1E1E,
0x1E21,0x1E20,
0x1E23,0x1E22,
0x1E25,0x1E24,
0x1E27,0x1E26,
0x1E29,0x1E28,
0x1E2B,0x1E2A,
0x1E2D,0x1E2C,
0x1E2F,0x1E2E,
0x1E31,0x1E30,
0x1E33,0x1E32,
0x1E35,0x1E34,
0x1E37,0x1E36,
0x1E39,0x1E38,
0x1E3B,0x1E3A,
0x1E3D,0x1E3C,
0x1E3F,0x1E3E,
0x1E41,0x1E40,
0x1E43,0x1E42,
0x1E45,0x1E44,
0x1E47,0x1E46,
0x1E49,0x1E48,
0x1E4B,0x1E4A,
0x1E4D,0x1E4C,
0x1E4F,0x1E4E,
0x1E51,0x1E50,
0x1E53,0x1E52,
0x1E55,0x1E54,
0x1E57,0x1E56,
0x1E59,0x1E58,
0x1E5B,0x1E5A,
0x1E5D,0x1E5C,
0x1E5F,0x1E5E,
0x1E61,0x1E60,
0x1E63,0x1E62,
0x1E65,0x1E64,
0x1E67,0x1E66,
0x1E69,0x1E68,
0x1E6B,0x1E6A,
0x1E6D,0x1E6C,
0x1E6F,0x1E6E,
0x1E71,0x1E70,
0x1E73,0x1E72,
0x1E75,0x1E74,
0x1E77,0x1E76,
0x1E79,0x1E78,
0x1E7B,0x1E7A,
0x1E7D,0x1E7C,
0x1E7F,0x1E7E,
0x1E81,0x1E80,
0x1E83,0x1E82,
0x1E85,0x1E84,
0x1E87,0x1E86,
0x1E89,0x1E88,
0x1E8B,0x1E8A,
0x1E8D,0x1E8C,
0x1E8F,0x1E8E,
0x1E91,0x1E90,
0x1E93,0x1E92,
0x1E95,0x1E94,
0x1EA1,0x1EA0,
0x1EA3,0x1EA2,
0x1EA5,0x1EA4,
0x1EA7,0x1EA6,
0x1EA9,0x1EA8,
0x1EAB,0x1EAA,
0x1EAD,0x1EAC,
0x1EAF,0x1EAE,
0x1EB1,0x1EB0,
0x1EB3,0x1EB2,
0x1EB5,0x1EB4,
0x1EB7,0x1EB6,
0x1EB9,0x1EB8,
0x1EBB,0x1EBA,
0x1EBD,0x1EBC,
0x1EBF,0x1EBE,
0x1EC1,0x1EC0,
0x1EC3,0x1EC2,
0x1EC5,0x1EC4,
0x1EC7,0x1EC6,
0x1EC9,0x1EC8,
0x1ECB,0x1ECA,
0x1ECD,0x1ECC,
0x1ECF,0x1ECE,
0x1ED1,0x1ED0,
0x1ED3,0x1ED2,
0x1ED5,0x1ED4,
0x1ED7,0x1ED6,
0x1ED9,0x1ED8,
0x1EDB,0x1EDA,
0x1EDD,0x1EDC,
0x1EDF,0x1EDE,
0x1EE1,0x1EE0,
0x1EE3,0x1EE2,
0x1EE5,0x1EE4,
0x1EE7,0x1EE6,
0x1EE9,0x1EE8,
0x1EEB,0x1EEA,
0x1EED,0x1EEC,
0x1EEF,0x1EEE,
0x1EF1,0x1EF0,
0x1EF3,0x1EF2,
0x1EF5,0x1EF4,
0x1EF7,0x1EF6,
0x1EF9,0x1EF8,
0x1F00,0x1F08,
0x1F01,0x1F09,
0x1F02,0x1F0A,
0x1F03,0x1F0B,
0x1F04,0x1F0C,
0x1F05,0x1F0D,
0x1F06,0x1F0E,
0x1F07,0x1F0F,
0x1F10,0x1F18,
0x1F11,0x1F19,
0x1F12,0x1F1A,
0x1F13,0x1F1B,
0x1F14,0x1F1C,
0x1F15,0x1F1D,
0x1F20,0x1F28,
0x1F21,0x1F29,
0x1F22,0x1F2A,
0x1F23,0x1F2B,
0x1F24,0x1F2C,
0x1F25,0x1F2D,
0x1F26,0x1F2E,
0x1F27,0x1F2F,
0x1F30,0x1F38,
0x1F31,0x1F39,
0x1F32,0x1F3A,
0x1F33,0x1F3B,
0x1F34,0x1F3C,
0x1F35,0x1F3D,
0x1F36,0x1F3E,
0x1F37,0x1F3F,
0x1F40,0x1F48,
0x1F41,0x1F49,
0x1F42,0x1F4A,
0x1F43,0x1F4B,
0x1F44,0x1F4C,
0x1F45,0x1F4D,
0x1F51,0x1F59,
0x1F53,0x1F5B,
0x1F55,0x1F5D,
0x1F57,0x1F5F,
0x1F60,0x1F68,
0x1F61, 0x1F69,
0x1F62, 0x1F6A,
0x1F63, 0x1F6B,
0x1F64, 0x1F6C,
0x1F65, 0x1F6D,
0x1F66, 0x1F6E,
0x1F67, 0x1F6F,
0x1F80, 0x1F88,
0x1F81, 0x1F89,
0x1F82, 0x1F8A,
0x1F83, 0x1F8B,
0x1F84, 0x1F8C,
0x1F85, 0x1F8D,
0x1F86, 0x1F8E,
0x1F87, 0x1F8F,
0x1F90, 0x1F98,
0x1F91, 0x1F99,
0x1F92, 0x1F9A,
0x1F93, 0x1F9B,
0x1F94, 0x1F9C,
0x1F95, 0x1F9D,
0x1F96, 0x1F9E,
0x1F97, 0x1F9F,
0x1FA0, 0x1FA8,
0x1FA1, 0x1FA9,
0x1FA2, 0x1FAA,
0x1FA3, 0x1FAB,
0x1FA4, 0x1FAC,
0x1FA5, 0x1FAD,
0x1FA6, 0x1FAE,
0x1FA7, 0x1FAF,
0x1FB0, 0x1FB8,
0x1FB1, 0x1FB9,
0x1FD0, 0x1FD8,
0x1FD1, 0x1FD9,
0x1FE0, 0x1FE8,
0x1FE1, 0x1FE9,
0x24D0, 0x24B6,
0x24D1, 0x24B7,
0x24D2, 0x24B8,
0x24D3, 0x24B9,
0x24D4, 0x24BA,
0x24D5, 0x24BB,
0x24D6, 0x24BC,
0x24D7, 0x24BD,
0x24D8, 0x24BE,
0x24D9, 0x24BF,
0x24DA, 0x24C0,
0x24DB, 0x24C1,
0x24DC, 0x24C2,
0x24DD, 0x24C3,
0x24DE, 0x24C4,
0x24DF, 0x24C5,
0x24E0, 0x24C6,
0x24E1, 0x24C7,
0x24E2, 0x24C8,
0x24E3, 0x24C9,
0x24E4, 0x24CA,
0x24E5, 0x24CB,
0x24E6, 0x24CC,
0x24E7, 0x24CD,
0x24E8, 0x24CE,
0x24E9, 0x24CF,
0xFF41, 0xFF21,
0xFF42, 0xFF22,
0xFF43, 0xFF23,
0xFF44, 0xFF24,
0xFF45, 0xFF25,
0xFF46, 0xFF26,
0xFF47, 0xFF27,
0xFF48, 0xFF28,
0xFF49, 0xFF29,
0xFF4A, 0xFF2A,
0xFF4B, 0xFF2B,
0xFF4C, 0xFF2C,
0xFF4D, 0xFF2D,
0xFF4E, 0xFF2E,
0xFF4F, 0xFF2F,
0xFF50, 0xFF30,
0xFF51, 0xFF31,
0xFF52, 0xFF32,
0xFF53, 0xFF33,
0xFF54, 0xFF34,
0xFF55, 0xFF35,
0xFF56, 0xFF36,
0xFF57, 0xFF37,
0xFF58, 0xFF38,
0xFF59, 0xFF39,
0xFF5A, 0xFF3A,

0, 0
};

struct InitLowerUpper
{
	InitLowerUpper()
	{
		for (int i = 0; i < 65536; i++)
		{
			lowerforupper[i] = i;
			upperforlower[i] = i;
		}
		for (int i = 0; loweruppercase[i]; i += 2)
		{
			auto lower = loweruppercase[i];
			auto upper = loweruppercase[i + 1];
			if (lowerforupper[upper] == upper) lowerforupper[upper] = lower;	// This mapping is ambiguous so only pick the first match.
			if (upperforlower[lower] == lower) upperforlower[lower] = upper;
			isuppermap[upper] = islowermap[lower] = true;
		}
		// Special treatment for the two variants of the small sigma in Greek.
		islowermap[0x3c2] = true;
		upperforlower[0x3c2] = 0x3a3;
		// Turkish 'I's.
		upperforlower[0x131] = 'I';
		lowerforupper[0x130] = 'i';
		islowermap[0x131] = true;
		isuppermap[0x130] = true;
	}
};

static InitLowerUpper initer;

bool myislower(int code)
{
	if (code >= 0 && code < 65536) return islowermap[code];
	return false;
}

bool myisupper(int code)
{
	if (code >= 0 && code < 65536) return isuppermap[code];
	return false;
}

std::wstring WideString(const char* cin)
{
	std::wstring buildbuffer;
	if (cin)
	{
		// This is a bit tricky because we need to support both UTF-8 and legacy content in ISO-8859-1 / Windows 1252
		// and thanks to user-side string manipulation it can be that a text mixes both.
		// To convert the string this uses the same function as all text printing in the engine.
		const uint8_t* in = (const uint8_t*)cin;
		while (*in) buildbuffer.push_back((wchar_t)GetCharFromString(in));
	}
	return buildbuffer;
}