// © 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. */ #if U_SHOW_CPLUSPLUS_API 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 // U_SHOW_CPLUSPLUS_API #endif // __EDITS_H__