| // © 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__ |
