#pragma once
// Copyright (c) 2002 - 2025 kio@little-bat.de
// BSD-2-Clause license
// https://opensource.org/licenses/BSD-2-Clause

#include "cstrings/cstrings.h"
#include "kio/kio.h"


/*
	convert ucs4char <-> legacy 8bit char
*/

typedef uint8		   ucs1char;
typedef uint16		   ucs2char;
typedef uint32		   ucs4char;
typedef const ucs2char ucs2table[256]; // map legacy char -> ucs2char

extern ucs2table legacy_charset_mac_roman;
extern ucs2table legacy_charset_ascii_ger;
extern ucs2table legacy_charset_rtos;
extern ucs2table legacy_charset_cp_437;
extern ucs2table legacy_charset_atari_st;


namespace ucs2
{

inline ucs2char from_8bit(char c, ucs2table t) noexcept { return t[uchar(c)]; }
inline ucs2char from_Latin1(char c) noexcept { return uchar(c); }
inline ucs2char from_Ascii(char c) noexcept { return c & 0x7f; }
inline ucs2char from_MacRoman(char c) noexcept { return legacy_charset_mac_roman[uchar(c)]; }
inline ucs2char from_AsciiGer(char c) noexcept { return legacy_charset_ascii_ger[uchar(c)]; }
inline ucs2char from_Rtos(char c) noexcept { return legacy_charset_rtos[uchar(c)]; }
inline ucs2char from_Cp437(char c) noexcept { return legacy_charset_cp_437[uchar(c)]; }
inline ucs2char from_AtariST(char c) noexcept { return legacy_charset_atari_st[uchar(c)]; }

static inline char _replacementchar() noexcept
{
	errno = notindestcharset;
	return '?';
}

// to_xxx functions set errno: notindestcharset
extern char to_8bit(ucs2char c, ucs2table t) noexcept;
inline char to_Latin1(ucs2char c) noexcept { return c <= 255 ? char(c) : _replacementchar(); }
inline char to_Ascii(ucs2char c) noexcept { return c <= 127 ? char(c) : _replacementchar(); }
inline char to_AsciiGer(ucs2char c) noexcept
{
	return (c | 0x20) <= 'z' && c != '@' ? char(c) : to_8bit(c, legacy_charset_ascii_ger);
}
inline char to_Rtos(ucs2char c) noexcept
{
	return (c | 0x20) <= 'z' && c != '@' ? char(c) : to_8bit(c, legacy_charset_rtos);
}
inline char to_MacRoman(ucs2char c) noexcept { return c <= 127 ? char(c) : to_8bit(c, legacy_charset_mac_roman); }
inline char to_Cp437(ucs2char c) noexcept { return c <= 127 ? char(c) : to_8bit(c, legacy_charset_cp_437); }
inline char to_AtariST(ucs2char c) noexcept { return c <= 127 ? char(c) : to_8bit(c, legacy_charset_atari_st); }

}; // namespace ucs2


namespace ucs4
{

inline ucs4char from_8bit(char c, ucs2table t) noexcept { return t[uchar(c)]; }
inline ucs4char from_Latin1(char c) noexcept { return uchar(c); }
inline ucs4char from_Ascii(char c) noexcept { return c & 0x7f; }
inline ucs4char from_MacRoman(char c) noexcept { return legacy_charset_mac_roman[uchar(c)]; }
inline ucs4char from_AsciiGer(char c) noexcept { return legacy_charset_ascii_ger[uchar(c)]; }
inline ucs4char from_Rtos(char c) noexcept { return legacy_charset_rtos[uchar(c)]; }
inline ucs4char from_Cp437(char c) noexcept { return legacy_charset_cp_437[uchar(c)]; }
inline ucs4char from_AtariST(char c) noexcept { return legacy_charset_atari_st[uchar(c)]; }

static inline char _replacementchar() noexcept
{
	errno = notindestcharset;
	return '?';
}

// to_xxx functions set errno: notindestcharset
extern char to_8bit(ucs4char c, ucs2table t) noexcept;
inline char to_Latin1(ucs4char c) noexcept { return c <= 255 ? char(c) : _replacementchar(); }
inline char to_Ascii(ucs4char c) noexcept { return c <= 127 ? char(c) : _replacementchar(); }
inline char to_AsciiGer(ucs4char c) noexcept
{
	return (c | 0x20) <= 'z' && c != '@' ? char(c) : to_8bit(c, legacy_charset_ascii_ger);
}
inline char to_Rtos(ucs4char c) noexcept
{
	return (c | 0x20) <= 'z' && c != '@' ? char(c) : to_8bit(c, legacy_charset_rtos);
}
inline char to_MacRoman(ucs4char c) noexcept { return c <= 127 ? char(c) : to_8bit(c, legacy_charset_mac_roman); }
inline char to_Cp437(ucs4char c) noexcept { return c <= 127 ? char(c) : to_8bit(c, legacy_charset_cp_437); }
inline char to_AtariST(ucs4char c) noexcept { return c <= 127 ? char(c) : to_8bit(c, legacy_charset_atari_st); }

}; // namespace ucs4