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RWUStringIterator Class Reference
[Unicode String Processing]

Bidirectional iterator that provides read-write access to the code points encoded by the code units within an RWUString. More...

#include <rw/i18n/RWUStringIterator.h>

List of all members.

Classes

class  RWUChar32Reference
 Provides transparent read-write access to a code point referenced by an RWUStringIterator. More...

Public Types

typedef size_t size_type
typedef int difference_type
typedef RWUChar32 value_type
typedef value_typepointer
typedef value_typereference
typedef
std::bidirectional_iterator_tag 
iterator_category

Public Member Functions

 RWUStringIterator ()
 RWUStringIterator (RWBasicUString &ustr)
 RWUStringIterator (const RWUStringIterator &iter)
RWUStringIteratoroperator= (const RWUStringIterator &iter)
void advanceCodePoints (int offset)
const RWUChar16data () const
RWUStringIteratoroperator++ ()
RWUStringIterator operator++ (int)
RWUStringIteratoroperator-- ()
RWUStringIterator operator-- (int)
RWUChar32 operator* () const
RWUChar32Reference operator* ()
 operator size_t () const

Related Functions

(Note that these are not member functions.)



bool operator== (const RWUStringIterator &lhs, const RWUStringIterator &rhs)
bool operator== (const RWUStringIterator &lhs, const RWUConstStringIterator &rhs)
bool operator!= (const RWUStringIterator &lhs, const RWUStringIterator &rhs)
bool operator!= (const RWUStringIterator &lhs, const RWUConstStringIterator &rhs)

Detailed Description

RWUStringIterator provides read-write access to the code points encoded by the code units within an RWUString. Code points within a given string are accessed in forward or reverse order, starting from the beginning or end of the string, respectively.

Attempting to dereference or advance an iterator that is positioned past the end of the string, such as the iterator returned by RWUString::endCodePointIterator(), throws RWBoundsErr.

The code points in an RWBasicUString can be changed using an RWUStringIterator. For example, consider an RWUStringIterator iter, and a code point stored in an RWUChar32 named codePoint. This statement changes the code point referenced by iter to the value in codePoint:

 *iter = codePoint;

Note that this operation may change the length of the original string if a surrogate pair (two 16-bit code units) is replaced with a single 16-bit code point, or vice-versa.

Bounds Checking

Bounds checking always occurs when repositioning or dereferencing an iterator. Any attempt to dereference an iterator that is in the past-the-end condition throws RWBoundsErr.

Conversion Errors

An RWUStringIterator converts code units into code points. Code points with scalar values greater than 0xFFFF are encoded as a pair of surrogate code units within the string. An RWUStringIterator cannot advance over or dereference an incomplete surrogate pair. RWUStringIterator throws RWConversionErr if an incomplete surrogate pair is encountered.

Examples

 #include <rw/i18n/RWUStringIterator.h>
 #include <rw/i18n/RWUString.h>
 #include <iostream>
 
 int main()
 {
   // "Hello,\n world.\n";
   RWUChar16 buf[16] = { 0x0048, 0x0065, 0x006c, 0x006c, 0x006f,
                         0x002c, 0x000d, 0x0020, 0x0077, 0x006f,
                         0x0072, 0x006c, 0x0064, 0x002e, 0x000d,
                         0x0000 };
 
   // Create the RWUString from the buffer
   RWUString         str(buf);
   RWUStringIterator it = str.beginCodePointIterator();
 
   // Replace all carriage return characters with NULL characters
   for (; it != str.endCodePointIterator(); ++it) {
     if (*it == RWUChar32(0x000d)) *it = RWUChar32(0x0000);
   } // for
 
   // Iterate forward over all code points in the string
   for (it = str.beginCodePointIterator();
        it != str.endCodePointIterator();
        ++it)
   {
     std::cout << std::hex << int(*it) << std::endl;
   } // for
 
   return 0;
 } // main

Program Output:

 48
 65
 6c
 6c
 6f
 2c
 0
 20
 77
 6f
 72
 6c
 64
 2e
 0

Related Classes

RWBasicUString, RWUString, RWUConstStringIterator


Member Typedef Documentation

Declares a conventional Standard C++ alias for the type used to represent iterator offsets and differences.

typedef std::bidirectional_iterator_tag RWUStringIterator::iterator_category

Declares this class to be a Standard C++ bidirectional iterator.

Declares a conventional Standard C++ alias for the value_type pointer.

Declares a conventional Standard C++ alias for the value_type reference.

Declares a conventional Standard C++ alias for the type used to represent sizes and indices.

Declares a conventional Standard C++ alias for the value type of returned by this iterator class.


Constructor & Destructor Documentation

RWUStringIterator::RWUStringIterator (  )  [inline]

Constructs a null, non-dereferencable iterator. The instance cannot be used until a dereferencable iterator is assigned to it. Any attempt to reposition or dereference a null iterator will cause an RWBoundsErr exception to be thrown.

RWUStringIterator::RWUStringIterator ( RWBasicUString ustr  ) 

Constructs an RWUStringIterator that is positioned at the first element of ustr, or past-the-end of ustr if ustr is empty.

RWUStringIterator::RWUStringIterator ( const RWUStringIterator iter  )  [inline]

Constructs an RWUStringIterator that references the same string and offset as iter.


Member Function Documentation

void RWUStringIterator::advanceCodePoints ( int  offset  ) 

Advances self by offset code points.

Exceptions:
RWBoundsErr Thrown if self is advanced before the first element or after one past the last element in the string. If offset is negative, the iterator is left pointing at the first element in the string. If offset is positive, the iterator is left pointing one past the last element in the string. RWBoundsErr is also thrown if self is null.
RWConversionErr Thrown if an incomplete surrogate pair is encountered where either the high surrogate or the low surrogate code unit is missing. If offset is negative, the iterator is positioned at the code unit immediately preceding the un-paired surrogate code unit, or at the first code unit of the string if the un-paired surrogate is the first code unit in the string. If offset is positive, the iterator is positioned at the code unit immediately following the un-paired surrogate code unit, or one past the last code unit of the string if the un-paired surrogate is the last code unit in the string.
const RWUChar16* RWUStringIterator::data (  )  const

Returns a pointer to the string contents at the location referenced by self.

The storage referenced by this pointer is owned by the RWBasicUString associated with this iterator. This storage may not be deleted or modified. The pointer becomes invalid if the RWBasicUString is modified or destroyed.

RWUStringIterator::operator size_t (  )  const [inline]

Returns the current code unit offset of self.

RWUStringIterator::RWUChar32Reference RWUStringIterator::operator* (  )  [inline]

Returns a reference object that provides read-write access to the code point located at the current iterator position. Invoked when dereferencing non-const RWUStringIterator objects. The result can be used as an RWUChar32 value, or as an l-value in an RWUChar32 assignment expression.

This method does not throw any exceptions, even if self is non-dereferencable or refers to a malformed surrogate pair. However, the reference object throws RWBoundsErr or RWConversionErr if self is used as an r-value or l-value in an expression and these conditions are detected.

RWUChar32 RWUStringIterator::operator* (  )  const

Returns the value of the code point currently referenced by self.

Exceptions:
RWBoundsErr Thrown if self is null or otherwise references a position outside the bounds of the string.
RWConversionErr Thrown if the code unit sequence found at the current iterator position contains an incomplete surrogate pair where either the high surrogate or the low surrogate code unit is missing.
RWUStringIterator RWUStringIterator::operator++ ( int   )  [inline]

Advances self to the next code point in the string, and returns a copy of the previous value of self.

Exceptions:
RWBoundsErr Thrown if self is already positioned one past the last code point in the string, or if self is null. The iterator position is left unchanged.
RWConversionErr Thrown if the code unit sequence found at the current iterator position contains an incomplete surrogate pair where either the high surrogate or the low surrogate code unit is missing. Self is left pointing at the code unit immediately following the unpaired surrogate code unit, or one past the last code unit of the string if the unpaired surrogate is the last code unit in the string.
RWUStringIterator& RWUStringIterator::operator++ (  ) 

Advances self to the next code point in the string and returns a reference to self.

Exceptions:
RWBoundsErr Thrown if self is already positioned one past the last code point in the string, or if self is null. The iterator position is left unchanged.
RWConversionErr Thrown if the code unit sequence found at the current iterator position contains an incomplete surrogate pair where either the high surrogate or the low surrogate code unit is missing. Self is left pointing at the code unit immediately following the unpaired surrogate code unit, or one past the last code unit of the string if the unpaired surrogate is the last code unit in the string.
RWUStringIterator RWUStringIterator::operator-- ( int   )  [inline]

Advances self to the previous code point in the string and returns a copy of the previous value of self.

Exceptions:
RWBoundsErr Thrown if self is already positioned at the beginning of the string, or if self is null. The iterator position is left unchanged.
RWConversionErr Thrown if the code unit sequence found at the current iterator position contains an incomplete surrogate pair where either the high surrogate or the low surrogate code unit is missing. Self is left pointing at the unpaired code unit.
RWUStringIterator& RWUStringIterator::operator-- (  ) 

Advances self to the previous code point in the string and returns a reference to self.

Exceptions:
RWBoundsErr Thrown if self is already positioned at the beginning of the string, or if self is null. The iterator position is left unchanged.
RWConversionErr Thrown if the code unit sequence found at the current iterator position contains an incomplete surrogate pair where either the high surrogate or the low surrogate code unit is missing. Self is left pointing at the unpaired code unit.
RWUStringIterator & RWUStringIterator::operator= ( const RWUStringIterator iter  )  [inline]

Changes self so it references the same string and offset as iter, and returns a reference to self.


Friends And Related Function Documentation

bool operator!= ( const RWUStringIterator lhs,
const RWUConstStringIterator rhs 
) [related]

Returns true if the two iterators reference different RWBasicUString objects, or if the code point offsets referenced by the iterators are different; otherwise, false.

bool operator!= ( const RWUStringIterator lhs,
const RWUStringIterator rhs 
) [related]

Returns true if the two iterators reference different RWBasicUString objects, or if the code point offsets referenced by the iterators are different; otherwise, false.

bool operator== ( const RWUStringIterator lhs,
const RWUConstStringIterator rhs 
) [related]

Returns true if both iterators reference the same RWBasicUString, and are positioned at the same code point offset within RWBasicUString; otherwise, false.

bool operator== ( const RWUStringIterator lhs,
const RWUStringIterator rhs 
) [related]

Returns true if both iterators reference the same RWBasicUString, and are positioned at the same code point offset within the RWBasicUString; otherwise, false.

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