Utf16Iterator Class Reference

Iterate code points of an UTF-16 encoded string. More...

#include <cc/Utf16Iterator>

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
	Utf16Iterator ()
	Create an invalid iterator.
	Utf16Iterator (const std::uint16_t *start, const std::uint16_t *end, const std::uint16_t *pos, ByteOrder endian=localEndian())
	Create a new iterator.
	Utf16Iterator (const Utf16Iterator &b)=default
Utf16Iterator &	operator++ ()
	Prefix increment operator: step one code point forward
Utf16Iterator &	operator-- ()
	Prefix decrement operator: step one code point backward
Utf16Iterator	operator++ (int)
	Postfix increment operator: step one code point forward and return old position.
Utf16Iterator	operator-- (int)
	Postfix decrement operator: step one code point backward and return old position.
Utf16Iterator &	operator+= (ptrdiff_t d)
	Assignment addition operator: iterate in forward direction a given distance d.
Utf16Iterator &	operator-= (ptrdiff_t d)
	Assignment substraction operator: iterate in backward direction a given distance d.
Utf16Iterator	operator+ (ptrdiff_t d) const
	Addition operator: get iterator in forward direction at distance d.
Utf16Iterator	operator- (ptrdiff_t d) const
	Substraction operator: get iterator in backward direction at distance d.
std::ptrdiff_t	operator- (const Utf16Iterator &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.
size_t	operator+ () const
	Unary plus operator: return the current decoding position as a byte offset.
bool	operator== (const Utf16Iterator &b) const
	Compare for equality.
bool	operator!= (const Utf16Iterator &b) const
	Compare for in-equality.

Detailed Description

Iterate code points of an UTF-16 encoded string.

The Utf16Iterator allows iterating the Unicode code points of an UTF-16 word sequence. The iterator will always halt at the string boundaries. If stepping over the string boundary the walker will switch to an invalid state and start 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 run over without error, but possibly illegal code points are delivered in this case. In both forward and backward iteration at least one illegal code point is delivered for a single ill-coded word.

Todo

create a test harness

Constructor & Destructor Documentation

Utf16Iterator() [1/2]

Utf16Iterator

(

)

Create an invalid iterator.

Utf16Iterator() [2/2]

Utf16Iterator	(	const std::uint16_t *	start,
		const std::uint16_t *	end,
		const std::uint16_t *	pos,
		ByteOrder	endian = localEndian() )

Create a new iterator.

Parameters

start	Pointer to start of UTF-16 encoded string
end	Pointer to end of UTF-16 encoded string (behind last valid word)
pos	Current position within the UTF-16 encoded string
endian	Byte order

Member Function Documentation

operator++() [1/2]

Utf16Iterator & operator++

(

)

Prefix increment operator: step one code point forward

operator--() [1/2]

Utf16Iterator & operator--

(

)

Prefix decrement operator: step one code point backward

operator++() [2/2]

Utf16Iterator operator++

(

int

)

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

operator--() [2/2]

Utf16Iterator operator--

(

int

)

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

operator+=()

Utf16Iterator & operator+=

(

ptrdiff_t

d

)

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

operator-=()

Utf16Iterator & operator-=

(

ptrdiff_t

d

)

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

operator+() [1/2]

Utf16Iterator operator+

(

ptrdiff_t

d

)

const

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

operator-() [1/2]

Utf16Iterator operator-

(

ptrdiff_t

d

)

const

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

operator-() [2/2]

std::ptrdiff_t operator-

(

const Utf16Iterator &

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]

size_t operator+

(

)

const

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

operator==()

bool operator==

(

const Utf16Iterator &

b

)

const

Compare for equality.

operator!=()

bool operator!=

(

const Utf16Iterator &

b

)

const

Compare for in-equality.