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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), numChanges(0),
errorCode_(U_ZERO_ERROR) {}
/**
* Copy constructor.
* @param other source edits
* @draft ICU 60
*/
Edits(const Edits &other) :
array(stackArray), capacity(STACK_CAPACITY), length(other.length),
delta(other.delta), numChanges(other.numChanges),
errorCode_(other.errorCode_) {
copyArray(other);
}
/**
* Move constructor, might leave src empty.
* This object will have the same contents that the source object had.
* @param src source edits
* @draft ICU 60
*/
Edits(Edits &&src) U_NOEXCEPT :
array(stackArray), capacity(STACK_CAPACITY), length(src.length),
delta(src.delta), numChanges(src.numChanges),
errorCode_(src.errorCode_) {
moveArray(src);
}
/**
* Destructor.
* @draft ICU 59
*/
~Edits();
/**
* Assignment operator.
* @param other source edits
* @return *this
* @draft ICU 60
*/
Edits &operator=(const Edits &other);
/**
* 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.
* @param src source edits
* @return *this
* @draft ICU 60
*/
Edits &operator=(Edits &&src) U_NOEXCEPT;
/**
* Resets the data but may not release memory.
* @draft ICU 59
*/
void reset() U_NOEXCEPT;
/**
* 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.
* @param outErrorCode Set to an error code if it does not contain one already
* and an error occurred while recording edits.
* Otherwise unchanged.
* @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 { return numChanges != 0; }
/**
* @return the number of change edits
* @draft ICU 60
*/
int32_t numberOfChanges() const { return numChanges; }
/**
* Access to the list of edits.
* @see getCoarseIterator
* @see getFineIterator
* @draft ICU 59
*/
struct U_COMMON_API Iterator U_FINAL : public UMemory {
/**
* Default constructor, empty iterator.
* @draft ICU 60
*/
Iterator() :
array(nullptr), index(0), length(0),
remaining(0), onlyChanges_(FALSE), coarse(FALSE),
dir(0), changed(FALSE), oldLength_(0), newLength_(0),
srcIndex(0), replIndex(0), destIndex(0) {}
/**
* 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.
* @param errorCode ICU 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.)
* @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
* @param errorCode ICU 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.)
* @return TRUE if the edit for the source index was found
* @draft ICU 59
*/
UBool findSourceIndex(int32_t i, UErrorCode &errorCode) {
return findIndex(i, TRUE, errorCode) == 0;
}
/**
* Finds the edit that contains the destination index.
* The destination 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 destination index
* @param errorCode ICU 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.)
* @return TRUE if the edit for the destination index was found
* @draft ICU 60
*/
UBool findDestinationIndex(int32_t i, UErrorCode &errorCode) {
return findIndex(i, FALSE, errorCode) == 0;
}
/**
* Returns the destination index corresponding to the given source index.
* If the source index is inside a change edit (not at its start),
* then the destination index at the end of that edit is returned,
* since there is no information about index mapping inside a change edit.
*
* (This means that indexes to the start and middle of an edit,
* for example around a grapheme cluster, are mapped to indexes
* encompassing the entire edit.
* The alternative, mapping an interior index to the start,
* would map such an interval to an empty one.)
*
* This operation will usually but not always modify this object.
* The iterator state after this search is undefined.
*
* @param i source index
* @param errorCode ICU 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.)
* @return destination index; undefined if i is not 0..string length
* @draft ICU 60
*/
int32_t destinationIndexFromSourceIndex(int32_t i, UErrorCode &errorCode);
/**
* Returns the source index corresponding to the given destination index.
* If the destination index is inside a change edit (not at its start),
* then the source index at the end of that edit is returned,
* since there is no information about index mapping inside a change edit.
*
* (This means that indexes to the start and middle of an edit,
* for example around a grapheme cluster, are mapped to indexes
* encompassing the entire edit.
* The alternative, mapping an interior index to the start,
* would map such an interval to an empty one.)
*
* This operation will usually but not always modify this object.
* The iterator state after this search is undefined.
*
* @param i destination index
* @param errorCode ICU 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.)
* @return source index; undefined if i is not 0..string length
* @draft ICU 60
*/
int32_t sourceIndexFromDestinationIndex(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 updateNextIndexes();
void updatePreviousIndexes();
UBool noNext();
UBool next(UBool onlyChanges, UErrorCode &errorCode);
UBool previous(UErrorCode &errorCode);
/** @return -1: error or i<0; 0: found; 1: i>=string length */
int32_t findIndex(int32_t i, UBool findSource, UErrorCode &errorCode);
const uint16_t *array;
int32_t index, length;
// 0 if we are not within compressed equal-length changes.
// Otherwise the number of remaining changes, including the current one.
int32_t remaining;
UBool onlyChanges_, coarse;
int8_t dir; // iteration direction: back(<0), initial(0), forward(>0)
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);
}
/**
* 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.<br>
* Edits ab reflect how substrings of input string a
* map to substrings of intermediate string b.<br>
* Edits bc reflect how substrings of intermediate string b
* map to substrings of output string c.<br>
* 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.
*
* @param ab reflects how substrings of input string a
* map to substrings of intermediate string b.
* @param bc reflects how substrings of intermediate string b
* map to substrings of output string c.
* @param errorCode ICU 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.)
* @return *this, with the merged edits appended
* @draft ICU 60
*/
Edits &mergeAndAppend(const Edits &ab, const Edits &bc, UErrorCode &errorCode);
private:
void releaseArray() U_NOEXCEPT;
Edits ©Array(const Edits &other);
Edits &moveArray(Edits &src) U_NOEXCEPT;
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;
int32_t numChanges;
UErrorCode errorCode_;
uint16_t stackArray[STACK_CAPACITY];
};
#endif // U_HIDE_DRAFT_API
U_NAMESPACE_END
#endif // __EDITS_H__