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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
// edits.h
// created: 2016dec30 Markus W. Scherer
#ifndef __EDITS_H__
#define __EDITS_H__
#include "unicode/utypes.h"
#include "unicode/uobject.h"
/**
* \file
* \brief C++ API: C++ class Edits for low-level string transformations on styled text.
*/
U_NAMESPACE_BEGIN
#ifndef U_HIDE_DRAFT_API
/**
* Records lengths of string edits but not replacement text.
* Supports replacements, insertions, deletions in linear progression.
* Does not support moving/reordering of text.
*
* 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.
*
* @draft ICU 59
*/
class U_COMMON_API Edits U_FINAL : public UMemory {
public:
/**
* Constructs an empty object.
* @draft ICU 59
*/
Edits() :
array(stackArray), capacity(STACK_CAPACITY), length(0), delta(0),
errorCode(U_ZERO_ERROR) {}
/**
* Destructor.
* @draft ICU 59
*/
~Edits();
/**
* Resets the data but may not release memory.
* @draft ICU 59
*/
void reset();
/**
* Adds a record for an unchanged segment of text.
* Normally called from inside ICU string transformation functions, not user code.
* @draft ICU 59
*/
void addUnchanged(int32_t unchangedLength);
/**
* Adds a record for a text replacement/insertion/deletion.
* Normally called from inside ICU string transformation functions, not user code.
* @draft ICU 59
*/
void addReplace(int32_t oldLength, int32_t newLength);
/**
* 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.
* @return TRUE if U_FAILURE(outErrorCode)
* @draft ICU 59
*/
UBool copyErrorTo(UErrorCode &outErrorCode);
/**
* How much longer is the new text compared with the old text?
* @return new length minus old length
* @draft ICU 59
*/
int32_t lengthDelta() const { return delta; }
/**
* @return TRUE if there are any change edits
* @draft ICU 59
*/
UBool hasChanges() const;
/**
* Access to the list of edits.
* @see getCoarseIterator
* @see getFineIterator
* @draft ICU 59
*/
struct U_COMMON_API Iterator U_FINAL : public UMemory {
/**
* Copy constructor.
* @draft ICU 59
*/
Iterator(const Iterator &other) = default;
/**
* Assignment operator.
* @draft ICU 59
*/
Iterator &operator=(const Iterator &other) = default;
/**
* Advances to the next edit.
* @return TRUE if there is another edit
* @draft ICU 59
*/
UBool next(UErrorCode &errorCode) { return next(onlyChanges_, errorCode); }
/**
* Finds the edit that contains the source index.
* The source index may be found in a non-change
* even if normal iteration would skip non-changes.
* Normal iteration can continue from a found edit.
*
* The iterator state before this search logically does not matter.
* (It may affect the performance of the search.)
*
* The iterator state after this search is undefined
* if the source index is out of bounds for the source string.
*
* @param i source index
* @return TRUE if the edit for the source index was found
* @draft ICU 59
*/
UBool findSourceIndex(int32_t i, UErrorCode &errorCode);
/**
* @return TRUE if this edit replaces oldLength() units with newLength() different ones.
* FALSE if oldLength units remain unchanged.
* @draft ICU 59
*/
UBool hasChange() const { return changed; }
/**
* @return the number of units in the original string which are replaced or remain unchanged.
* @draft ICU 59
*/
int32_t oldLength() const { return oldLength_; }
/**
* @return the number of units in the modified string, if hasChange() is TRUE.
* Same as oldLength if hasChange() is FALSE.
* @draft ICU 59
*/
int32_t newLength() const { return newLength_; }
/**
* @return the current index into the source string
* @draft ICU 59
*/
int32_t sourceIndex() const { return srcIndex; }
/**
* @return the current index into the replacement-characters-only string,
* not counting unchanged spans
* @draft ICU 59
*/
int32_t replacementIndex() const { return replIndex; }
/**
* @return the current index into the full destination string
* @draft ICU 59
*/
int32_t destinationIndex() const { return destIndex; }
private:
friend class Edits;
Iterator(const uint16_t *a, int32_t len, UBool oc, UBool crs);
int32_t readLength(int32_t head);
void updateIndexes();
UBool noNext();
UBool next(UBool onlyChanges, UErrorCode &errorCode);
const uint16_t *array;
int32_t index, length;
int32_t remaining;
UBool onlyChanges_, coarse;
UBool changed;
int32_t oldLength_, newLength_;
int32_t srcIndex, replIndex, destIndex;
};
/**
* Returns an Iterator for coarse-grained changes for simple string updates.
* Skips non-changes.
* @return an Iterator that merges adjacent changes.
* @draft ICU 59
*/
Iterator getCoarseChangesIterator() const {
return Iterator(array, length, TRUE, TRUE);
}
/**
* Returns an Iterator for coarse-grained changes and non-changes for simple string updates.
* @return an Iterator that merges adjacent changes.
* @draft ICU 59
*/
Iterator getCoarseIterator() const {
return Iterator(array, length, FALSE, TRUE);
}
/**
* Returns an Iterator for fine-grained changes for modifying styled text.
* Skips non-changes.
* @return an Iterator that separates adjacent changes.
* @draft ICU 59
*/
Iterator getFineChangesIterator() const {
return Iterator(array, length, TRUE, FALSE);
}
/**
* Returns an Iterator for fine-grained changes and non-changes for modifying styled text.
* @return an Iterator that separates adjacent changes.
* @draft ICU 59
*/
Iterator getFineIterator() const {
return Iterator(array, length, FALSE, FALSE);
}
private:
Edits(const Edits &) = delete;
Edits &operator=(const Edits &) = delete;
void setLastUnit(int32_t last) { array[length - 1] = (uint16_t)last; }
int32_t lastUnit() const { return length > 0 ? array[length - 1] : 0xffff; }
void append(int32_t r);
UBool growArray();
static const int32_t STACK_CAPACITY = 100;
uint16_t *array;
int32_t capacity;
int32_t length;
int32_t delta;
UErrorCode errorCode;
uint16_t stackArray[STACK_CAPACITY];
};
#endif // U_HIDE_DRAFT_API
U_NAMESPACE_END
#endif // __EDITS_H__
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