ICU 62.1  62.1
Data Structures | Public Member Functions
icu::Edits Class Referencefinal

Records lengths of string edits but not replacement text. More...

#include <edits.h>

Inheritance diagram for icu::Edits:
icu::UMemory

Data Structures

struct  Iterator
 Access to the list of edits. More...
 

Public Member Functions

 Edits ()
 Constructs an empty object. More...
 
 Edits (const Edits &other)
 Copy constructor. More...
 
 Edits (Edits &&src)
 Move constructor, might leave src empty. More...
 
 ~Edits ()
 Destructor. More...
 
Editsoperator= (const Edits &other)
 Assignment operator. More...
 
Editsoperator= (Edits &&src)
 Move assignment operator, might leave src empty. More...
 
void reset ()
 Resets the data but may not release memory. More...
 
void addUnchanged (int32_t unchangedLength)
 Adds a no-change edit: a record for an unchanged segment of text. More...
 
void addReplace (int32_t oldLength, int32_t newLength)
 Adds a change edit: a record for a text replacement/insertion/deletion. More...
 
UBool copyErrorTo (UErrorCode &outErrorCode)
 Sets the UErrorCode if an error occurred while recording edits. More...
 
int32_t lengthDelta () const
 How much longer is the new text compared with the old text? More...
 
UBool hasChanges () const
 
int32_t numberOfChanges () const
 
Iterator getCoarseChangesIterator () const
 Returns an Iterator for coarse-grained change edits (adjacent change edits are treated as one). More...
 
Iterator getCoarseIterator () const
 Returns an Iterator for coarse-grained change and no-change edits (adjacent change edits are treated as one). More...
 
Iterator getFineChangesIterator () const
 Returns an Iterator for fine-grained change edits (full granularity of change edits is retained). More...
 
Iterator getFineIterator () const
 Returns an Iterator for fine-grained change and no-change edits (full granularity of change edits is retained). More...
 
EditsmergeAndAppend (const Edits &ab, const Edits &bc, UErrorCode &errorCode)
 Merges the two input Edits and appends the result to this object. More...
 

Detailed Description

Records lengths of string edits but not replacement text.

Supports replacements, insertions, deletions in linear progression. Does not support moving/reordering of text.

There are two types of edits: change edits and no-change edits. Add edits to instances of this class using addReplace(int, int) (for change edits) and addUnchanged(int) (for no-change edits). Change edits are retained with full granularity, whereas adjacent no-change edits are always merged together. In no-change edits, there is a one-to-one mapping between code points in the source and destination strings.

After all edits have been added, instances of this class should be considered immutable, and an Edits::Iterator can be used for queries.

There are four flavors of Edits::Iterator:

For example, consider the string "abcßDeF", which case-folds to "abcssdef". This string has the following fine edits:

and the following coarse edits (note how adjacent change edits get merged together):

The "fine changes" and "coarse changes" iterators will step through only the change edits when their Edits::Iterator#next() methods are called. They are identical to the non-change iterators when their Edits::Iterator#findSourceIndex(int) or Edits::Iterator#findDestinationIndex(int) methods are used to walk through the string.

For examples of how to use this class, see the test TestCaseMapEditsIteratorDocs in UCharacterCaseTest.java.

An Edits object tracks a separate UErrorCode, but ICU string transformation functions (e.g., case mapping functions) merge any such errors into their API's UErrorCode.

Stable:
ICU 59

Definition at line 77 of file edits.h.

Constructor & Destructor Documentation

◆ Edits() [1/3]

icu::Edits::Edits ( )
inline

Constructs an empty object.

Stable:
ICU 59

Definition at line 83 of file edits.h.

◆ Edits() [2/3]

icu::Edits::Edits ( const Edits other)
inline

Copy constructor.

Parameters
othersource edits
Draft:
This API may be changed in the future versions and was introduced in ICU 60

Definition at line 91 of file edits.h.

◆ Edits() [3/3]

icu::Edits::Edits ( Edits &&  src)
inline

Move constructor, might leave src empty.

This object will have the same contents that the source object had.

Parameters
srcsource edits
Draft:
This API may be changed in the future versions and was introduced in ICU 60

Definition at line 103 of file edits.h.

◆ ~Edits()

icu::Edits::~Edits ( )

Destructor.

Stable:
ICU 59

Member Function Documentation

◆ addReplace()

void icu::Edits::addReplace ( int32_t  oldLength,
int32_t  newLength 
)

Adds a change edit: a record for a text replacement/insertion/deletion.

Normally called from inside ICU string transformation functions, not user code.

Stable:
ICU 59

◆ addUnchanged()

void icu::Edits::addUnchanged ( int32_t  unchangedLength)

Adds a no-change edit: a record for an unchanged segment of text.

Normally called from inside ICU string transformation functions, not user code.

Stable:
ICU 59

◆ copyErrorTo()

UBool icu::Edits::copyErrorTo ( UErrorCode outErrorCode)

Sets the UErrorCode if an error occurred while recording edits.

Preserves older error codes in the outErrorCode. Normally called from inside ICU string transformation functions, not user code.

Parameters
outErrorCodeSet to an error code if it does not contain one already and an error occurred while recording edits. Otherwise unchanged.
Returns
TRUE if U_FAILURE(outErrorCode)
Stable:
ICU 59

◆ getCoarseChangesIterator()

Iterator icu::Edits::getCoarseChangesIterator ( ) const
inline

Returns an Iterator for coarse-grained change edits (adjacent change edits are treated as one).

Can be used to perform simple string updates. Skips no-change edits.

Returns
an Iterator that merges adjacent changes.
Stable:
ICU 59

Definition at line 439 of file edits.h.

References TRUE.

◆ getCoarseIterator()

Iterator icu::Edits::getCoarseIterator ( ) const
inline

Returns an Iterator for coarse-grained change and no-change edits (adjacent change edits are treated as one).

Can be used to perform simple string updates. Adjacent change edits are treated as one edit.

Returns
an Iterator that merges adjacent changes.
Stable:
ICU 59

Definition at line 451 of file edits.h.

References FALSE, and TRUE.

◆ getFineChangesIterator()

Iterator icu::Edits::getFineChangesIterator ( ) const
inline

Returns an Iterator for fine-grained change edits (full granularity of change edits is retained).

Can be used for modifying styled text. Skips no-change edits.

Returns
an Iterator that separates adjacent changes.
Stable:
ICU 59

Definition at line 463 of file edits.h.

References FALSE, and TRUE.

◆ getFineIterator()

Iterator icu::Edits::getFineIterator ( ) const
inline

Returns an Iterator for fine-grained change and no-change edits (full granularity of change edits is retained).

Can be used for modifying styled text.

Returns
an Iterator that separates adjacent changes.
Stable:
ICU 59

Definition at line 474 of file edits.h.

References FALSE.

◆ hasChanges()

UBool icu::Edits::hasChanges ( ) const
inline
Returns
TRUE if there are any change edits
Stable:
ICU 59

Definition at line 174 of file edits.h.

◆ lengthDelta()

int32_t icu::Edits::lengthDelta ( ) const
inline

How much longer is the new text compared with the old text?

Returns
new length minus old length
Stable:
ICU 59

Definition at line 169 of file edits.h.

◆ mergeAndAppend()

Edits& icu::Edits::mergeAndAppend ( const Edits ab,
const Edits bc,
UErrorCode errorCode 
)

Merges the two input Edits and appends the result to this object.

Consider two string transformations (for example, normalization and case mapping) where each records Edits in addition to writing an output string.
Edits ab reflect how substrings of input string a map to substrings of intermediate string b.
Edits bc reflect how substrings of intermediate string b map to substrings of output string c.
This function merges ab and bc such that the additional edits recorded in this object reflect how substrings of input string a map to substrings of output string c.

If unrelated Edits are passed in where the output string of the first has a different length than the input string of the second, then a U_ILLEGAL_ARGUMENT_ERROR is reported.

Parameters
abreflects how substrings of input string a map to substrings of intermediate string b.
bcreflects how substrings of intermediate string b map to substrings of output string c.
errorCodeICU error code. Its input value must pass the U_SUCCESS() test, or else the function returns immediately. Check for U_FAILURE() on output or use with function chaining. (See User Guide for details.)
Returns
*this, with the merged edits appended
Draft:
This API may be changed in the future versions and was introduced in ICU 60

◆ numberOfChanges()

int32_t icu::Edits::numberOfChanges ( ) const
inline
Returns
the number of change edits
Draft:
This API may be changed in the future versions and was introduced in ICU 60

Definition at line 181 of file edits.h.

◆ operator=() [1/2]

Edits& icu::Edits::operator= ( const Edits other)

Assignment operator.

Parameters
othersource edits
Returns
*this
Draft:
This API may be changed in the future versions and was introduced in ICU 60

◆ operator=() [2/2]

Edits& icu::Edits::operator= ( Edits &&  src)

Move assignment operator, might leave src empty.

This object will have the same contents that the source object had. The behavior is undefined if *this and src are the same object.

Parameters
srcsource edits
Returns
*this
Draft:
This API may be changed in the future versions and was introduced in ICU 60

◆ reset()

void icu::Edits::reset ( )

Resets the data but may not release memory.

Stable:
ICU 59

The documentation for this class was generated from the following file: