396 lines
9.5 KiB
C++
396 lines
9.5 KiB
C++
/*
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*******************************************************************************
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* Copyright (C) 1996-2001, International Business Machines Corporation and *
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* others. All Rights Reserved. *
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*******************************************************************************
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*/
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//===============================================================================
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//
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// File sortkey.cpp
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//
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//
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//
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// Created by: Helena Shih
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//
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// Modification History:
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//
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// Date Name Description
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//
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// 6/20/97 helena Java class name change.
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// 6/23/97 helena Added comments to make code more readable.
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// 6/26/98 erm Canged to use byte arrays instead of UnicodeString
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// 7/31/98 erm hashCode: minimum inc should be 2 not 1,
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// Cleaned up operator=
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// 07/12/99 helena HPUX 11 CC port.
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// 03/06/01 synwee Modified compareTo, to handle the result of
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// 2 string similar in contents, but one is longer
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// than the other
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//===============================================================================
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#include "unicode/utypes.h"
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#if !UCONFIG_NO_COLLATION
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#include "unicode/sortkey.h"
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#include "cmemory.h"
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#include "uhash.h"
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U_NAMESPACE_BEGIN
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// A hash code of kInvalidHashCode indicates that the has code needs
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// to be computed. A hash code of kEmptyHashCode is used for empty keys
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// and for any key whose computed hash code is kInvalidHashCode.
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#define kInvalidHashCode ((int32_t)0)
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#define kEmptyHashCode ((int32_t)1)
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const char CollationKey::fgClassID=0;
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CollationKey::CollationKey()
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: UObject(), fBogus(FALSE), fCount(0), fCapacity(0),
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fHashCode(kEmptyHashCode), fBytes(NULL)
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{
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}
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// Create a collation key from a bit array.
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CollationKey::CollationKey(const uint8_t* newValues, int32_t count)
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: UObject(), fBogus(FALSE), fCount(count), fCapacity(count),
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fHashCode(kInvalidHashCode)
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{
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fBytes = (uint8_t *)uprv_malloc(count);
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if (fBytes == NULL)
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{
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setToBogus();
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return;
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}
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uprv_memcpy(fBytes, newValues, fCount);
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}
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CollationKey::CollationKey(const CollationKey& other)
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: UObject(other), fBogus(FALSE), fCount(other.fCount), fCapacity(other.fCapacity),
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fHashCode(other.fHashCode), fBytes(NULL)
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{
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if (other.fBogus)
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{
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setToBogus();
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return;
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}
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fBytes = (uint8_t *)uprv_malloc(fCapacity);
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if (fBytes == NULL)
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{
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setToBogus();
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return;
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}
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uprv_memcpy(fBytes, other.fBytes, other.fCount);
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if(fCapacity>fCount) {
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uprv_memset(fBytes+fCount, 0, fCapacity-fCount);
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}
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}
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CollationKey::~CollationKey()
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{
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uprv_free(fBytes);
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}
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void CollationKey::adopt(uint8_t *values, int32_t count) {
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if(fBytes != NULL) {
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uprv_free(fBytes);
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}
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fBogus = FALSE;
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fBytes = values;
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fCount = count;
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fCapacity = count;
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fHashCode = kInvalidHashCode;
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}
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// set the key to an empty state
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CollationKey&
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CollationKey::reset()
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{
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fCount = 0;
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fBogus = FALSE;
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fHashCode = kEmptyHashCode;
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return *this;
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}
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// set the key to a "bogus" or invalid state
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CollationKey&
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CollationKey::setToBogus()
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{
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uprv_free(fBytes);
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fBytes = NULL;
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fCapacity = 0;
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fCount = 0;
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fHashCode = kInvalidHashCode;
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return *this;
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}
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UBool
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CollationKey::operator==(const CollationKey& source) const
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{
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return (this->fCount == source.fCount &&
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(this->fBytes == source.fBytes ||
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uprv_memcmp(this->fBytes, source.fBytes, this->fCount) == 0));
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}
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const CollationKey&
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CollationKey::operator=(const CollationKey& other)
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{
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if (this != &other)
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{
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if (other.isBogus())
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{
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return setToBogus();
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}
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if (other.fBytes != NULL)
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{
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ensureCapacity(other.fCount);
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if (isBogus())
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{
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return *this;
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}
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fHashCode = other.fHashCode;
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uprv_memcpy(fBytes, other.fBytes, fCount);
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}
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else
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{
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fCount = 0;
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fBogus = FALSE;
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fHashCode = kEmptyHashCode;
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}
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}
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return *this;
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}
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// Bitwise comparison for the collation keys.
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// NOTE: this is somewhat messy 'cause we can't count
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// on memcmp returning the exact values which match
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// Collator::EComparisonResult
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Collator::EComparisonResult
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CollationKey::compareTo(const CollationKey& target) const
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{
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uint8_t *src = this->fBytes;
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uint8_t *tgt = target.fBytes;
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// are we comparing the same string
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if (src == tgt)
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return Collator::EQUAL;
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/*
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int count = (this->fCount < target.fCount) ? this->fCount : target.fCount;
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if (count == 0)
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{
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// If count is 0, at least one of the keys is empty.
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// An empty key is always LESS than a non-empty one
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// and EQUAL to another empty
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if (this->fCount < target.fCount)
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{
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return Collator::LESS;
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}
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if (this->fCount > target.fCount)
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{
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return Collator::GREATER;
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}
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return Collator::EQUAL;
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}
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*/
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int minLength;
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Collator::EComparisonResult result;
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// are we comparing different lengths?
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if (this->fCount != target.fCount) {
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if (this->fCount < target.fCount) {
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minLength = this->fCount;
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result = Collator::LESS;
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}
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else {
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minLength = target.fCount;
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result = Collator::GREATER;
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}
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}
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else {
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minLength = target.fCount;
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result = Collator::EQUAL;
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}
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if (minLength > 0) {
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int diff = uprv_memcmp(src, tgt, minLength);
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if (diff > 0) {
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return Collator::GREATER;
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}
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else
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if (diff < 0) {
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return Collator::LESS;
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}
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}
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return result;
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/*
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if (result < 0)
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{
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return Collator::LESS;
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}
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if (result > 0)
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{
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return Collator::GREATER;
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}
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return Collator::EQUAL;
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*/
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}
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// Bitwise comparison for the collation keys.
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UCollationResult
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CollationKey::compareTo(const CollationKey& target, UErrorCode &status) const
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{
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if(U_SUCCESS(status)) {
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uint8_t *src = this->fBytes;
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uint8_t *tgt = target.fBytes;
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// are we comparing the same string
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if (src == tgt)
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return UCOL_EQUAL;
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int minLength;
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UCollationResult result;
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// are we comparing different lengths?
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if (this->fCount != target.fCount) {
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if (this->fCount < target.fCount) {
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minLength = this->fCount;
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result = UCOL_LESS;
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}
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else {
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minLength = target.fCount;
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result = UCOL_GREATER;
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}
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}
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else {
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minLength = target.fCount;
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result = UCOL_EQUAL;
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}
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if (minLength > 0) {
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int diff = uprv_memcmp(src, tgt, minLength);
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if (diff > 0) {
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return UCOL_GREATER;
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}
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else
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if (diff < 0) {
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return UCOL_LESS;
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}
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}
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return result;
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} else {
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return UCOL_EQUAL;
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}
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}
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CollationKey&
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CollationKey::ensureCapacity(int32_t newSize)
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{
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if (fCapacity < newSize)
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{
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uprv_free(fBytes);
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fBytes = (uint8_t *)uprv_malloc(newSize);
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if (fBytes == NULL)
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{
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return setToBogus();
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}
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uprv_memset(fBytes, 0, fCapacity);
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fCapacity = newSize;
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}
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fBogus = FALSE;
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fCount = newSize;
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fHashCode = kInvalidHashCode;
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return *this;
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}
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#ifdef U_USE_COLLATION_KEY_DEPRECATES
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// Create a copy of the byte array.
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uint8_t*
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CollationKey::toByteArray(int32_t& count) const
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{
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uint8_t *result = (uint8_t*) uprv_malloc( sizeof(uint8_t) * fCount );
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if (result == NULL)
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{
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count = 0;
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}
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else
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{
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count = fCount;
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uprv_memcpy(result, fBytes, fCount);
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}
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return result;
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}
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#endif
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int32_t
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CollationKey::hashCode() const
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{
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// (Cribbed from UnicodeString)
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// We cache the hashCode; when it becomes invalid, due to any change to the
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// string, we note this by setting it to kInvalidHashCode. [LIU]
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// Note: This method is semantically const, but physically non-const.
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if (fHashCode == kInvalidHashCode)
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{
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UHashTok key;
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key.pointer = fBytes;
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((CollationKey *)this)->fHashCode = uhash_hashChars(key);
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#if 0
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// We compute the hash by iterating sparsely over 64 (at most) characters
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// spaced evenly through the string. For each character, we multiply the
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// previous hash value by a prime number and add the new character in,
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// in the manner of a additive linear congruential random number generator,
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// thus producing a pseudorandom deterministic value which should be well
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// distributed over the output range. [LIU]
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const uint8_t *p = fBytes, *limit = fBytes + fCount;
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int32_t inc = (fCount >= 256) ? fCount/128 : 2; // inc = max(fSize/64, 1);
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int32_t hash = 0;
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while (p < limit)
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{
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hash = ( hash * 37 ) + ((p[0] << 8) + p[1]);
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p += inc;
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}
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// If we happened to get kInvalidHashCode, replace it with kEmptyHashCode
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if (hash == kInvalidHashCode)
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{
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hash = kEmptyHashCode;
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}
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((CollationKey *)this)->fHashCode = hash; // cast away const
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#endif
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}
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return fHashCode;
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}
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U_NAMESPACE_END
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#endif /* #if !UCONFIG_NO_COLLATION */
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