Utf8Iterator Class Reference

Iterate code points of an UTF-8 encoded string. More...

#include <cc/Utf8Iterator>

Public Types
using	iterator_category = std::bidirectional_iterator_tag
using	value_type = char32_t
using	difference_type = std::ptrdiff_t
using	pointer = void
using	reference = char32_t

Public Member Functions
	Utf8Iterator ()
	Create an invalid iterator.
	Utf8Iterator (const char *start, const char *end, const char *pos)
	Create a new iterator.
	Utf8Iterator (const Utf8Iterator &b)=default
Utf8Iterator &	operator++ ()
	Prefix increment operator: step a single code point forward
Utf8Iterator &	operator-- ()
	Prefix decrement operator: step a single code point backward
Utf8Iterator	operator++ (int)
	Postfix increment operator: step a single code point forward and return old position.
Utf8Iterator	operator-- (int)
	Postfix decrement operator: step a single code point backward and return old position.
Utf8Iterator &	operator+= (std::ptrdiff_t d)
	Assignment addition operator: step in forward direction a given distance d.
Utf8Iterator &	operator-= (std::ptrdiff_t d)
	Assignment substraction operator: step in backward direction a given distance d.
Utf8Iterator	operator+ (std::ptrdiff_t d) const
	Addition operator: get iterator in forward direction at given distance d.
Utf8Iterator	operator- (std::ptrdiff_t d) const
	Substraction operator: get iterator in backward direction at given distance d.
std::ptrdiff_t	operator- (const Utf8Iterator &b) const
	Difference operator: compute distance in number of characters.
	operator bool () const
	Cast to bool operator: indicate if this iterator can step forward another code point.
char32_t	operator* () const
	Dereference operator: decode current code point.
std::ptrdiff_t	operator+ () const
	Unary plus operator: return the current decoding position as a byte offset.
bool	operator== (const Utf8Iterator &b) const
	Compare for equality.
bool	operator!= (const Utf8Iterator &b) const
	Compare for in-equality.

Detailed Description

Iterate code points of an UTF-8 encoded string.

The Utf8Iterator allows iterating Unicode characters of an UTF-8 byte sequence. The iterator will always halt at the string boundaries. If stepping over the string boundary the iterator will automatically switch to an invalid state delivering zero code points.

If placed at a string's terminating zero character it is possible to step backwards into the string.

Illegal code sequences are overrun without error. In forward iteration corrupted code prefixes may lead to at maximum one correct character overrun and up to 3 additional corrupt characters delivered. Any bit error outside the code prefixes will lead to at most one illegal character delivered – with one exception: switching to all bits zero (a zero byte is always string terminating).

Constructor & Destructor Documentation

Utf8Iterator() [1/2]

Utf8Iterator

(

)

Create an invalid iterator.

Utf8Iterator() [2/2]

Utf8Iterator	(	const char *	start,
		const char *	end,
		const char *	pos )

Create a new iterator.

Parameters

start	Pointer to start of UTF-8 encoded string
end	Pointer to end of UTF-8 encoded string (behind last valid byte)
pos	Current position within the UTF-8 encoded string

Member Function Documentation

operator++() [1/2]

Utf8Iterator & operator++

(

)

Prefix increment operator: step a single code point forward

operator--() [1/2]

Utf8Iterator & operator--

(

)

Prefix decrement operator: step a single code point backward

operator++() [2/2]

Utf8Iterator operator++

(

int

)

Postfix increment operator: step a single code point forward and return old position.

operator--() [2/2]

Utf8Iterator operator--

(

int

)

Postfix decrement operator: step a single code point backward and return old position.

operator+=()

Utf8Iterator & operator+=

(

std::ptrdiff_t

d

)

Assignment addition operator: step in forward direction a given distance d.

operator-=()

Utf8Iterator & operator-=

(

std::ptrdiff_t

d

)

Assignment substraction operator: step in backward direction a given distance d.

operator+() [1/2]

Utf8Iterator operator+

(

std::ptrdiff_t

d

)

const

Addition operator: get iterator in forward direction at given distance d.

operator-() [1/2]

Utf8Iterator operator-

(

std::ptrdiff_t

d

)

const

Substraction operator: get iterator in backward direction at given distance d.

operator-() [2/2]

std::ptrdiff_t operator-

(

const Utf8Iterator &

b

)

const

Difference operator: compute distance in number of characters.

operator bool()

operator bool ( ) const

explicit

Cast to bool operator: indicate if this iterator can step forward another code point.

operator*()

char32_t operator*

(

)

const

Dereference operator: decode current code point.

operator+() [2/2]

std::ptrdiff_t operator+

(

)

const

Unary plus operator: return the current decoding position as a byte offset.

operator==()

bool operator==

(

const Utf8Iterator &

b

)

const

Compare for equality.

operator!=()

bool operator!=

(

const Utf8Iterator &

b

)

const

Compare for in-equality.