255 lines
9.7 KiB
C++
255 lines
9.7 KiB
C++
/*
|
|
*****************************************************************************************
|
|
* *
|
|
* COPYRIGHT: *
|
|
* (C) Copyright Taligent, Inc., 1996 *
|
|
* (C) Copyright International Business Machines Corporation, 1996-1999 *
|
|
* Licensed Material - Program-Property of IBM - All Rights Reserved. *
|
|
* US Government Users Restricted Rights - Use, duplication, or disclosure *
|
|
* restricted by GSA ADP Schedule Contract with IBM Corp. *
|
|
* *
|
|
*****************************************************************************************
|
|
*/
|
|
//===============================================================================
|
|
//
|
|
// 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 "utypes.h"
|
|
#include "unistr.h"
|
|
#include "coll.h"
|
|
|
|
|
|
/**
|
|
* 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>
|
|
* . 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;
|
|
* . }
|
|
* . //...
|
|
* </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
|
|
*/
|
|
class U_I18N_API CollationKey {
|
|
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.
|
|
*/
|
|
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.
|
|
* @see #createBits
|
|
*/
|
|
CollationKey(const uint8_t* values,
|
|
int32_t count);
|
|
|
|
/**
|
|
* Copy constructor.
|
|
*/
|
|
CollationKey(const CollationKey& other);
|
|
/**
|
|
* Sort key destructor.
|
|
*/
|
|
~CollationKey();
|
|
|
|
/**
|
|
* Assignment operator
|
|
*/
|
|
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.
|
|
*/
|
|
bool_t 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.
|
|
*/
|
|
bool_t 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.
|
|
*/
|
|
bool_t 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.
|
|
*/
|
|
const uint8_t* getByteArray(int32_t& count) const;
|
|
|
|
/**
|
|
* 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.
|
|
*/
|
|
uint8_t* toByteArray(int32_t& count) const;
|
|
|
|
/**
|
|
* Convenience method which does a string(bit-wise) comparison of the
|
|
* two collation keys.
|
|
* @param sourceKey source collation key
|
|
* @param targetKey target collation key
|
|
* @return Returns Collator::LESS if sourceKey < targetKey,
|
|
* Collator::GREATER if sourceKey > targetKey and Collator::EQUAL
|
|
* otherwise.
|
|
*/
|
|
Collator::EComparisonResult compareTo(const CollationKey& target) 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
|
|
*/
|
|
int32_t hashCode(void) const;
|
|
|
|
private:
|
|
/**
|
|
* Returns an array of the collation key values as 16-bit integers.
|
|
* The caller owns the storage and must delete it.
|
|
* @param size output parameter of the number of collation key values
|
|
* @return a pointer to an array of 16-bit collation key values.
|
|
*/
|
|
uint16_t* copyValues(int32_t &size) const;
|
|
|
|
/*
|
|
* Creates a collation key with a string.
|
|
*/
|
|
CollationKey(const UnicodeString& value);
|
|
|
|
int32_t storeBytes(int32_t cursor, uint32_t byteValue);
|
|
int32_t storeUnicodeString(int32_t cursor, const UnicodeString &value);
|
|
void reverseBytes(int32_t from, int32_t to);
|
|
CollationKey& ensureCapacity(int32_t newSize);
|
|
CollationKey& copyUnicodeString(const UnicodeString &value);
|
|
CollationKey& setToBogus(void);
|
|
CollationKey& reset(void);
|
|
|
|
friend class RuleBasedCollator;
|
|
|
|
static const int32_t kInvalidHashCode;
|
|
static const int32_t kEmptyHashCode;
|
|
|
|
bool_t fBogus;
|
|
int32_t fCount;
|
|
int32_t fCapacity;
|
|
int32_t fHashCode;
|
|
uint8_t* fBytes;
|
|
};
|
|
|
|
inline bool_t
|
|
CollationKey::operator!=(const CollationKey& other) const
|
|
{
|
|
return !(*this == other);
|
|
}
|
|
|
|
inline bool_t
|
|
CollationKey::isBogus() const
|
|
{
|
|
return fBogus;
|
|
}
|
|
|
|
inline const uint8_t*
|
|
CollationKey::getByteArray(int32_t &count) const
|
|
{
|
|
count = fCount;
|
|
return fBytes;
|
|
}
|
|
|
|
inline UTextOffset
|
|
CollationKey::storeBytes(UTextOffset cursor, uint32_t byteValue)
|
|
{
|
|
fBytes[cursor++] = (uint8_t) (byteValue >> 8);
|
|
fBytes[cursor++] = (uint8_t) byteValue;
|
|
|
|
return cursor;
|
|
}
|
|
|
|
#endif
|