TT5.hpp File Reference

TT5 A 5 bit code designed for encoding identifiers. More...

#include "TTauri/Foundation/required.hpp"
#include "TTauri/Foundation/throw_exception.hpp"
#include "TTauri/Foundation/bigint.hpp"
#include <string>
#include <string_view>
#include <cstdint>

Go to the source code of this file.

Typedefs
using	tt::tt5_64 = uint64_t
using	tt::tt5_128 = ubig128

Functions
constexpr uint16_t	tt::tt5_code (uint16_t page, uint16_t prefix, uint16_t value)
	Create a tt5_code.
constexpr uint16_t	tt::tt5_code_table_generate_entry (uint8_t c) noexcept
	Convert a unicode character to a tt5-code.
constexpr auto	tt::tt5_code_table_generator () noexcept
constexpr uint64_t	tt::tt5_code_from_char (uint8_t c) noexcept
template<typename T >
constexpr ssize_t	tt::tt5_add_code (T &r, uint16_t code) noexcept
constexpr bool	tt::tt5_want_to_lock (uint64_t ring) noexcept
	Check if we want to use the lock command.
template<typename T >
constexpr T	tt::tt5_encode (char const *str)
	Encode a UTF-8 string into an integer using TT5-encoding.
template<typename T >
constexpr T	tt::tt5_encode (std::string const &s)
	Encode a UTF-8 string into an integer using TT5-encoding.
template<typename T >
constexpr T	tt::tt5_reverse (T value) noexcept
	Reverse the character in a TT5-packet-integer.
constexpr uint8_t	tt::char_from_tt5_page0 (char *&str, uint8_t code, uint8_t locked_page) noexcept
constexpr uint8_t	tt::char_from_tt5_page1 (char *&str, uint8_t code, uint8_t locked_page) noexcept
constexpr uint8_t	tt::char_from_tt5_page2 (char *&str, uint8_t code, uint8_t &locked_page) noexcept
constexpr uint8_t	tt::char_from_tt5_binary (char *&str, uint8_t code, uint8_t locked_page, uint8_t high_bits) noexcept
template<typename T >
constexpr void	tt::fill_buffer_from_tt5 (char *str, T const &value) noexcept
	Convert a tt5 value to a string.
template<typename T >
std::string	tt::tt5_decode (T const &value) noexcept
	Decode a TT5-packed integer into a UTF-8 string.
constexpr auto	tt::operator""_tt5 (char const *str, size_t) noexcept
constexpr auto	tt::operator""_tt5_64 (char const *str, size_t) noexcept
constexpr auto	tt::operator""_tt5_128 (char const *str, size_t) noexcept

Variables
constexpr auto	tt::tt5_code_table = tt5_code_table_generator()

Detailed Description

TT5 A 5 bit code designed for encoding identifiers.

#	P0	P1	P2
00	NUL	NUL	NUL
01	a	A	0
02	b	B	1
03	c	C	2
04	d	D	3
05	e	E	4
06	f	F	5
07	g	G	6
08	h	H	7
09	i	I	8
0a	j	J	9
0b	k	K	,
0c	l	L	:
0d	m	M	;
0e	n	M	/
0f	o	O	LF
10	p	P	B0
11	q	Q	B1
12	r	R	B2
13	s	S	B3
14	t	T	B4
15	u	U	B5
16	v	V	B6
17	w	W	B7
18	x	X	L0
19	y	Y	L1
1a	z	Z	L2
1b	_	_	_
1c	.	.	.
1d	-	-	-
1e	S1	S0	S0
1f	S2	S2	S1

Pages

There are three pages. The current- and locked page is page 0 at the start of the text.

By using the commands S0, S1 or S2 you can temporarilly switch the current page until a single character is emited, afterwards the current page is switched back to the locked page.

By using the command L0, L1 or L2 you can change the current- and locked page.

Binary

The page 2 commands B* are used to emit a single byte. The lower 3 bits of the B* command are used as the high 3-bits of the byte and the next 5 bits are used for the lower 5 bits of the byte.

End of text

End of text is denoted by the NUL character or when there is no more room in the integer that contains the text.

Function Documentation

fill_buffer_from_tt5()

template<typename T >

constexpr void tt::fill_buffer_from_tt5 ( char * str, T const & value )

constexprnoexcept

Convert a tt5 value to a string.

Parameters

str	The buffer to return the string into, there must be enough space.

operator""_tt5()

constexpr auto tt::operator""_tt5 ( char const * str, size_t  )

constexprnoexcept

_tt5 string literal

operator""_tt5_128()

constexpr auto tt::operator""_tt5_128 ( char const * str, size_t  )

constexprnoexcept

_tt5_128 string literal

operator""_tt5_64()

constexpr auto tt::operator""_tt5_64 ( char const * str, size_t  )

constexprnoexcept

_tt5_128 string literal

tt5_code()

constexpr uint16_t tt::tt5_code ( uint16_t page, uint16_t prefix, uint16_t value )

constexpr

Create a tt5_code.

Returns

11:10 page_nr, 9:5 prefix-code, 4:0 data (pre-shifted by 48 bits)

tt5_code_table_generate_entry()

constexpr uint16_t tt::tt5_code_table_generate_entry ( uint8_t c )

constexprnoexcept

Convert a unicode character to a tt5-code.

Returns

11:10 page_nr, 9:5 prefix-code, 4:0 data (pre-shifted by 48 bits)

tt5_decode()

template<typename T >

std::string tt::tt5_decode ( T const & value )

noexcept

Decode a TT5-packed integer into a UTF-8 string.

Parameters

value

The string packed into an integer, with the last character in the least significant bits.

Returns

An UTF-8 encoded string.

tt5_encode() [1/2]

template<typename T >

constexpr T tt::tt5_encode ( char const * str )

constexpr

Encode a UTF-8 string into an integer using TT5-encoding.

Parameters

str	Nul terminated UTF-8 string.

Returns

The string packed into an integer, with the last character in the least significant bits.

tt5_encode() [2/2]

template<typename T >

constexpr T tt::tt5_encode ( std::string const & s )

constexpr

Encode a UTF-8 string into an integer using TT5-encoding.

Parameters

str	UTF-8 string.

Returns

The string packed into an integer, with the last character in the least significant bits.

tt5_reverse()

template<typename T >

constexpr T tt::tt5_reverse ( T value )

constexprnoexcept

Reverse the character in a TT5-packet-integer.

Parameters

value

The string packed into an integer, with the last character in the least significant bits.

Returns

The string packed into an integer, with the first character in the least significant bits.

tt5_want_to_lock()

constexpr bool tt::tt5_want_to_lock ( uint64_t ring )

constexprnoexcept

Check if we want to use the lock command.

We need at least 4 consequtive characters in the same page. We ignore page 3 (character '.', '-', '_').