| // © 2016 and later: Unicode, Inc. and others. |
| // License & terms of use: http://www.unicode.org/copyright.html |
| /* |
| ***************************************************************************** |
| * Copyright (C) 1996-2014, International Business Machines Corporation and others. |
| * All Rights Reserved. |
| ***************************************************************************** |
| * |
| * File sortkey.h |
| * |
| * Created by: Helena Shih |
| * |
| * Modification History: |
| * |
| * Date Name Description |
| * |
| * 6/20/97 helena Java class name change. |
| * 8/18/97 helena Added internal API documentation. |
| * 6/26/98 erm Changed to use byte arrays and memcmp. |
| ***************************************************************************** |
| */ |
| |
| #ifndef SORTKEY_H |
| #define SORTKEY_H |
| |
| #include "unicode/utypes.h" |
| |
| /** |
| * \file |
| * \brief C++ API: Keys for comparing strings multiple times. |
| */ |
| |
| #if !UCONFIG_NO_COLLATION |
| |
| #include "unicode/uobject.h" |
| #include "unicode/unistr.h" |
| #include "unicode/coll.h" |
| |
| U_NAMESPACE_BEGIN |
| |
| /* forward declaration */ |
| class RuleBasedCollator; |
| class CollationKeyByteSink; |
| |
| /** |
| * |
| * Collation keys are generated by the Collator class. Use the CollationKey objects |
| * instead of Collator to compare strings multiple times. A CollationKey |
| * preprocesses the comparison information from the Collator object to |
| * make the comparison faster. If you are not going to comparing strings |
| * multiple times, then using the Collator object is generally faster, |
| * since it only processes as much of the string as needed to make a |
| * comparison. |
| * <p> For example (with strength == tertiary) |
| * <p>When comparing "Abernathy" to "Baggins-Smythworthy", Collator |
| * only needs to process a couple of characters, while a comparison |
| * with CollationKeys will process all of the characters. On the other hand, |
| * if you are doing a sort of a number of fields, it is much faster to use |
| * CollationKeys, since you will be comparing strings multiple times. |
| * <p>Typical use of CollationKeys are in databases, where you store a CollationKey |
| * in a hidden field, and use it for sorting or indexing. |
| * |
| * <p>Example of use: |
| * <pre> |
| * \code |
| * UErrorCode success = U_ZERO_ERROR; |
| * Collator* myCollator = Collator::createInstance(success); |
| * CollationKey* keys = new CollationKey [3]; |
| * myCollator->getCollationKey("Tom", keys[0], success ); |
| * myCollator->getCollationKey("Dick", keys[1], success ); |
| * myCollator->getCollationKey("Harry", keys[2], success ); |
| * |
| * // Inside body of sort routine, compare keys this way: |
| * CollationKey tmp; |
| * if(keys[0].compareTo( keys[1] ) > 0 ) { |
| * tmp = keys[0]; keys[0] = keys[1]; keys[1] = tmp; |
| * } |
| * //... |
| * \endcode |
| * </pre> |
| * <p>Because Collator::compare()'s algorithm is complex, it is faster to sort |
| * long lists of words by retrieving collation keys with Collator::getCollationKey(). |
| * You can then cache the collation keys and compare them using CollationKey::compareTo(). |
| * <p> |
| * <strong>Note:</strong> <code>Collator</code>s with different Locale, |
| * CollationStrength and DecompositionMode settings will return different |
| * CollationKeys for the same set of strings. Locales have specific |
| * collation rules, and the way in which secondary and tertiary differences |
| * are taken into account, for example, will result in different CollationKeys |
| * for same strings. |
| * <p> |
| |
| * @see Collator |
| * @see RuleBasedCollator |
| * @version 1.3 12/18/96 |
| * @author Helena Shih |
| * @stable ICU 2.0 |
| */ |
| class U_I18N_API CollationKey : public UObject { |
| public: |
| /** |
| * This creates an empty collation key based on the null string. An empty |
| * collation key contains no sorting information. When comparing two empty |
| * collation keys, the result is Collator::EQUAL. Comparing empty collation key |
| * with non-empty collation key is always Collator::LESS. |
| * @stable ICU 2.0 |
| */ |
| CollationKey(); |
| |
| |
| /** |
| * Creates a collation key based on the collation key values. |
| * @param values the collation key values |
| * @param count number of collation key values, including trailing nulls. |
| * @stable ICU 2.0 |
| */ |
| CollationKey(const uint8_t* values, |
| int32_t count); |
| |
| /** |
| * Copy constructor. |
| * @param other the object to be copied. |
| * @stable ICU 2.0 |
| */ |
| CollationKey(const CollationKey& other); |
| |
| /** |
| * Sort key destructor. |
| * @stable ICU 2.0 |
| */ |
| virtual ~CollationKey(); |
| |
| /** |
| * Assignment operator |
| * @param other the object to be copied. |
| * @stable ICU 2.0 |
| */ |
| const CollationKey& operator=(const CollationKey& other); |
| |
| /** |
| * Compare if two collation keys are the same. |
| * @param source the collation key to compare to. |
| * @return Returns true if two collation keys are equal, false otherwise. |
| * @stable ICU 2.0 |
| */ |
| UBool operator==(const CollationKey& source) const; |
| |
| /** |
| * Compare if two collation keys are not the same. |
| * @param source the collation key to compare to. |
| * @return Returns TRUE if two collation keys are different, FALSE otherwise. |
| * @stable ICU 2.0 |
| */ |
| UBool operator!=(const CollationKey& source) const; |
| |
| |
| /** |
| * Test to see if the key is in an invalid state. The key will be in an |
| * invalid state if it couldn't allocate memory for some operation. |
| * @return Returns TRUE if the key is in an invalid, FALSE otherwise. |
| * @stable ICU 2.0 |
| */ |
| UBool isBogus(void) const; |
| |
| /** |
| * Returns a pointer to the collation key values. The storage is owned |
| * by the collation key and the pointer will become invalid if the key |
| * is deleted. |
| * @param count the output parameter of number of collation key values, |
| * including any trailing nulls. |
| * @return a pointer to the collation key values. |
| * @stable ICU 2.0 |
| */ |
| const uint8_t* getByteArray(int32_t& count) const; |
| |
| #ifdef U_USE_COLLATION_KEY_DEPRECATES |
| /** |
| * Extracts the collation key values into a new array. The caller owns |
| * this storage and should free it. |
| * @param count the output parameter of number of collation key values, |
| * including any trailing nulls. |
| * @obsolete ICU 2.6. Use getByteArray instead since this API will be removed in that release. |
| */ |
| uint8_t* toByteArray(int32_t& count) const; |
| #endif |
| |
| #ifndef U_HIDE_DEPRECATED_API |
| /** |
| * Convenience method which does a string(bit-wise) comparison of the |
| * two collation keys. |
| * @param target target collation key to be compared with |
| * @return Returns Collator::LESS if sourceKey < targetKey, |
| * Collator::GREATER if sourceKey > targetKey and Collator::EQUAL |
| * otherwise. |
| * @deprecated ICU 2.6 use the overload with error code |
| */ |
| Collator::EComparisonResult compareTo(const CollationKey& target) const; |
| #endif /* U_HIDE_DEPRECATED_API */ |
| |
| /** |
| * Convenience method which does a string(bit-wise) comparison of the |
| * two collation keys. |
| * @param target target collation key to be compared with |
| * @param status error code |
| * @return Returns UCOL_LESS if sourceKey < targetKey, |
| * UCOL_GREATER if sourceKey > targetKey and UCOL_EQUAL |
| * otherwise. |
| * @stable ICU 2.6 |
| */ |
| UCollationResult compareTo(const CollationKey& target, UErrorCode &status) const; |
| |
| /** |
| * Creates an integer that is unique to the collation key. NOTE: this |
| * is not the same as String.hashCode. |
| * <p>Example of use: |
| * <pre> |
| * . UErrorCode status = U_ZERO_ERROR; |
| * . Collator *myCollation = Collator::createInstance(Locale::US, status); |
| * . if (U_FAILURE(status)) return; |
| * . CollationKey key1, key2; |
| * . UErrorCode status1 = U_ZERO_ERROR, status2 = U_ZERO_ERROR; |
| * . myCollation->getCollationKey("abc", key1, status1); |
| * . if (U_FAILURE(status1)) { delete myCollation; return; } |
| * . myCollation->getCollationKey("ABC", key2, status2); |
| * . if (U_FAILURE(status2)) { delete myCollation; return; } |
| * . // key1.hashCode() != key2.hashCode() |
| * </pre> |
| * @return the hash value based on the string's collation order. |
| * @see UnicodeString#hashCode |
| * @stable ICU 2.0 |
| */ |
| int32_t hashCode(void) const; |
| |
| /** |
| * ICU "poor man's RTTI", returns a UClassID for the actual class. |
| * @stable ICU 2.2 |
| */ |
| virtual UClassID getDynamicClassID() const; |
| |
| /** |
| * ICU "poor man's RTTI", returns a UClassID for this class. |
| * @stable ICU 2.2 |
| */ |
| static UClassID U_EXPORT2 getStaticClassID(); |
| |
| private: |
| /** |
| * Replaces the current bytes buffer with a new one of newCapacity |
| * and copies length bytes from the old buffer to the new one. |
| * @return the new buffer, or NULL if the allocation failed |
| */ |
| uint8_t *reallocate(int32_t newCapacity, int32_t length); |
| /** |
| * Set a new length for a new sort key in the existing fBytes. |
| */ |
| void setLength(int32_t newLength); |
| |
| uint8_t *getBytes() { |
| return (fFlagAndLength >= 0) ? fUnion.fStackBuffer : fUnion.fFields.fBytes; |
| } |
| const uint8_t *getBytes() const { |
| return (fFlagAndLength >= 0) ? fUnion.fStackBuffer : fUnion.fFields.fBytes; |
| } |
| int32_t getCapacity() const { |
| return (fFlagAndLength >= 0) ? (int32_t)sizeof(fUnion) : fUnion.fFields.fCapacity; |
| } |
| int32_t getLength() const { return fFlagAndLength & 0x7fffffff; } |
| |
| /** |
| * Set the CollationKey to a "bogus" or invalid state |
| * @return this CollationKey |
| */ |
| CollationKey& setToBogus(void); |
| /** |
| * Resets this CollationKey to an empty state |
| * @return this CollationKey |
| */ |
| CollationKey& reset(void); |
| |
| /** |
| * Allow private access to RuleBasedCollator |
| */ |
| friend class RuleBasedCollator; |
| friend class CollationKeyByteSink; |
| |
| // Class fields. sizeof(CollationKey) is intended to be 48 bytes |
| // on a machine with 64-bit pointers. |
| // We use a union to maximize the size of the internal buffer, |
| // similar to UnicodeString but not as tight and complex. |
| |
| // (implicit) *vtable; |
| /** |
| * Sort key length and flag. |
| * Bit 31 is set if the buffer is heap-allocated. |
| * Bits 30..0 contain the sort key length. |
| */ |
| int32_t fFlagAndLength; |
| /** |
| * Unique hash value of this CollationKey. |
| * Special value 2 if the key is bogus. |
| */ |
| mutable int32_t fHashCode; |
| /** |
| * fUnion provides 32 bytes for the internal buffer or for |
| * pointer+capacity. |
| */ |
| union StackBufferOrFields { |
| /** fStackBuffer is used iff fFlagAndLength>=0, else fFields is used */ |
| uint8_t fStackBuffer[32]; |
| struct { |
| uint8_t *fBytes; |
| int32_t fCapacity; |
| } fFields; |
| } fUnion; |
| }; |
| |
| inline UBool |
| CollationKey::operator!=(const CollationKey& other) const |
| { |
| return !(*this == other); |
| } |
| |
| inline UBool |
| CollationKey::isBogus() const |
| { |
| return fHashCode == 2; // kBogusHashCode |
| } |
| |
| inline const uint8_t* |
| CollationKey::getByteArray(int32_t &count) const |
| { |
| count = getLength(); |
| return getBytes(); |
| } |
| |
| U_NAMESPACE_END |
| |
| #endif /* #if !UCONFIG_NO_COLLATION */ |
| |
| #endif |
