341 lines
11 KiB
C++
341 lines
11 KiB
C++
// © 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
|