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Diffstat (limited to 'deps/icu-small/source/i18n/unicode/sortkey.h')
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diff --git a/deps/icu-small/source/i18n/unicode/sortkey.h b/deps/icu-small/source/i18n/unicode/sortkey.h new file mode 100644 index 0000000000..b4629d4e24 --- /dev/null +++ b/deps/icu-small/source/i18n/unicode/sortkey.h @@ -0,0 +1,338 @@ +/* + ***************************************************************************** + * 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 |