440 lines
13 KiB
C++
440 lines
13 KiB
C++
/*
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*******************************************************************************
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* Copyright (C) 2010-2011, International Business Machines
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* Corporation and others. All Rights Reserved.
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*******************************************************************************
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* file name: bytestrie.cpp
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* encoding: US-ASCII
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* tab size: 8 (not used)
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* indentation:4
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*
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* created on: 2010sep25
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* created by: Markus W. Scherer
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*/
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#include "unicode/utypes.h"
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#include "unicode/bytestream.h"
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#include "unicode/bytestrie.h"
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#include "unicode/uobject.h"
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#include "cmemory.h"
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#include "uassert.h"
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U_NAMESPACE_BEGIN
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BytesTrie::~BytesTrie() {
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uprv_free(ownedArray_);
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}
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// lead byte already shifted right by 1.
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int32_t
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BytesTrie::readValue(const uint8_t *pos, int32_t leadByte) {
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int32_t value;
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if(leadByte<kMinTwoByteValueLead) {
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value=leadByte-kMinOneByteValueLead;
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} else if(leadByte<kMinThreeByteValueLead) {
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value=((leadByte-kMinTwoByteValueLead)<<8)|*pos;
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} else if(leadByte<kFourByteValueLead) {
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value=((leadByte-kMinThreeByteValueLead)<<16)|(pos[0]<<8)|pos[1];
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} else if(leadByte==kFourByteValueLead) {
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value=(pos[0]<<16)|(pos[1]<<8)|pos[2];
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} else {
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value=(pos[0]<<24)|(pos[1]<<16)|(pos[2]<<8)|pos[3];
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}
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return value;
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}
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const uint8_t *
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BytesTrie::jumpByDelta(const uint8_t *pos) {
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int32_t delta=*pos++;
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if(delta<kMinTwoByteDeltaLead) {
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// nothing to do
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} else if(delta<kMinThreeByteDeltaLead) {
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delta=((delta-kMinTwoByteDeltaLead)<<8)|*pos++;
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} else if(delta<kFourByteDeltaLead) {
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delta=((delta-kMinThreeByteDeltaLead)<<16)|(pos[0]<<8)|pos[1];
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pos+=2;
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} else if(delta==kFourByteDeltaLead) {
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delta=(pos[0]<<16)|(pos[1]<<8)|pos[2];
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pos+=3;
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} else {
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delta=(pos[0]<<24)|(pos[1]<<16)|(pos[2]<<8)|pos[3];
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pos+=4;
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}
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return pos+delta;
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}
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UStringTrieResult
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BytesTrie::current() const {
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const uint8_t *pos=pos_;
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if(pos==NULL) {
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return USTRINGTRIE_NO_MATCH;
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} else {
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int32_t node;
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return (remainingMatchLength_<0 && (node=*pos)>=kMinValueLead) ?
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valueResult(node) : USTRINGTRIE_NO_VALUE;
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}
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}
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UStringTrieResult
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BytesTrie::branchNext(const uint8_t *pos, int32_t length, int32_t inByte) {
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// Branch according to the current byte.
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if(length==0) {
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length=*pos++;
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}
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++length;
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// The length of the branch is the number of bytes to select from.
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// The data structure encodes a binary search.
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while(length>kMaxBranchLinearSubNodeLength) {
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if(inByte<*pos++) {
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length>>=1;
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pos=jumpByDelta(pos);
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} else {
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length=length-(length>>1);
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pos=skipDelta(pos);
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}
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}
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// Drop down to linear search for the last few bytes.
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// length>=2 because the loop body above sees length>kMaxBranchLinearSubNodeLength>=3
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// and divides length by 2.
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do {
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if(inByte==*pos++) {
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UStringTrieResult result;
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int32_t node=*pos;
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U_ASSERT(node>=kMinValueLead);
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if(node&kValueIsFinal) {
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// Leave the final value for getValue() to read.
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result=USTRINGTRIE_FINAL_VALUE;
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} else {
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// Use the non-final value as the jump delta.
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++pos;
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// int32_t delta=readValue(pos, node>>1);
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node>>=1;
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int32_t delta;
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if(node<kMinTwoByteValueLead) {
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delta=node-kMinOneByteValueLead;
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} else if(node<kMinThreeByteValueLead) {
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delta=((node-kMinTwoByteValueLead)<<8)|*pos++;
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} else if(node<kFourByteValueLead) {
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delta=((node-kMinThreeByteValueLead)<<16)|(pos[0]<<8)|pos[1];
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pos+=2;
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} else if(node==kFourByteValueLead) {
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delta=(pos[0]<<16)|(pos[1]<<8)|pos[2];
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pos+=3;
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} else {
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delta=(pos[0]<<24)|(pos[1]<<16)|(pos[2]<<8)|pos[3];
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pos+=4;
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}
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// end readValue()
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pos+=delta;
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node=*pos;
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result= node>=kMinValueLead ? valueResult(node) : USTRINGTRIE_NO_VALUE;
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}
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pos_=pos;
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return result;
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}
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--length;
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pos=skipValue(pos);
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} while(length>1);
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if(inByte==*pos++) {
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pos_=pos;
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int32_t node=*pos;
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return node>=kMinValueLead ? valueResult(node) : USTRINGTRIE_NO_VALUE;
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} else {
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stop();
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return USTRINGTRIE_NO_MATCH;
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}
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}
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UStringTrieResult
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BytesTrie::nextImpl(const uint8_t *pos, int32_t inByte) {
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for(;;) {
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int32_t node=*pos++;
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if(node<kMinLinearMatch) {
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return branchNext(pos, node, inByte);
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} else if(node<kMinValueLead) {
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// Match the first of length+1 bytes.
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int32_t length=node-kMinLinearMatch; // Actual match length minus 1.
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if(inByte==*pos++) {
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remainingMatchLength_=--length;
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pos_=pos;
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return (length<0 && (node=*pos)>=kMinValueLead) ?
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valueResult(node) : USTRINGTRIE_NO_VALUE;
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} else {
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// No match.
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break;
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}
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} else if(node&kValueIsFinal) {
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// No further matching bytes.
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break;
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} else {
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// Skip intermediate value.
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pos=skipValue(pos, node);
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// The next node must not also be a value node.
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U_ASSERT(*pos<kMinValueLead);
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}
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}
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stop();
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return USTRINGTRIE_NO_MATCH;
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}
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UStringTrieResult
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BytesTrie::next(int32_t inByte) {
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const uint8_t *pos=pos_;
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if(pos==NULL) {
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return USTRINGTRIE_NO_MATCH;
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}
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if(inByte<0) {
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inByte+=0x100;
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}
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int32_t length=remainingMatchLength_; // Actual remaining match length minus 1.
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if(length>=0) {
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// Remaining part of a linear-match node.
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if(inByte==*pos++) {
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remainingMatchLength_=--length;
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pos_=pos;
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int32_t node;
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return (length<0 && (node=*pos)>=kMinValueLead) ?
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valueResult(node) : USTRINGTRIE_NO_VALUE;
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} else {
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stop();
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return USTRINGTRIE_NO_MATCH;
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}
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}
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return nextImpl(pos, inByte);
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}
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UStringTrieResult
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BytesTrie::next(const char *s, int32_t sLength) {
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if(sLength<0 ? *s==0 : sLength==0) {
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// Empty input.
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return current();
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}
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const uint8_t *pos=pos_;
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if(pos==NULL) {
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return USTRINGTRIE_NO_MATCH;
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}
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int32_t length=remainingMatchLength_; // Actual remaining match length minus 1.
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for(;;) {
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// Fetch the next input byte, if there is one.
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// Continue a linear-match node without rechecking sLength<0.
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int32_t inByte;
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if(sLength<0) {
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for(;;) {
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if((inByte=*s++)==0) {
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remainingMatchLength_=length;
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pos_=pos;
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int32_t node;
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return (length<0 && (node=*pos)>=kMinValueLead) ?
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valueResult(node) : USTRINGTRIE_NO_VALUE;
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}
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if(length<0) {
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remainingMatchLength_=length;
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break;
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}
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if(inByte!=*pos) {
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stop();
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return USTRINGTRIE_NO_MATCH;
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}
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++pos;
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--length;
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}
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} else {
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for(;;) {
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if(sLength==0) {
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remainingMatchLength_=length;
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pos_=pos;
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int32_t node;
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return (length<0 && (node=*pos)>=kMinValueLead) ?
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valueResult(node) : USTRINGTRIE_NO_VALUE;
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}
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inByte=*s++;
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--sLength;
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if(length<0) {
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remainingMatchLength_=length;
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break;
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}
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if(inByte!=*pos) {
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stop();
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return USTRINGTRIE_NO_MATCH;
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}
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++pos;
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--length;
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}
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}
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for(;;) {
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int32_t node=*pos++;
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if(node<kMinLinearMatch) {
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UStringTrieResult result=branchNext(pos, node, inByte);
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if(result==USTRINGTRIE_NO_MATCH) {
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return USTRINGTRIE_NO_MATCH;
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}
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// Fetch the next input byte, if there is one.
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if(sLength<0) {
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if((inByte=*s++)==0) {
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return result;
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}
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} else {
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if(sLength==0) {
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return result;
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}
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inByte=*s++;
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--sLength;
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}
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if(result==USTRINGTRIE_FINAL_VALUE) {
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// No further matching bytes.
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stop();
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return USTRINGTRIE_NO_MATCH;
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}
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pos=pos_; // branchNext() advanced pos and wrote it to pos_ .
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} else if(node<kMinValueLead) {
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// Match length+1 bytes.
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length=node-kMinLinearMatch; // Actual match length minus 1.
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if(inByte!=*pos) {
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stop();
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return USTRINGTRIE_NO_MATCH;
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}
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++pos;
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--length;
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break;
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} else if(node&kValueIsFinal) {
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// No further matching bytes.
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stop();
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return USTRINGTRIE_NO_MATCH;
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} else {
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// Skip intermediate value.
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pos=skipValue(pos, node);
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// The next node must not also be a value node.
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U_ASSERT(*pos<kMinValueLead);
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}
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}
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}
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}
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const uint8_t *
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BytesTrie::findUniqueValueFromBranch(const uint8_t *pos, int32_t length,
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UBool haveUniqueValue, int32_t &uniqueValue) {
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while(length>kMaxBranchLinearSubNodeLength) {
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++pos; // ignore the comparison byte
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if(NULL==findUniqueValueFromBranch(jumpByDelta(pos), length>>1, haveUniqueValue, uniqueValue)) {
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return NULL;
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}
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length=length-(length>>1);
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pos=skipDelta(pos);
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}
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do {
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++pos; // ignore a comparison byte
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// handle its value
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int32_t node=*pos++;
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UBool isFinal=(UBool)(node&kValueIsFinal);
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int32_t value=readValue(pos, node>>1);
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pos=skipValue(pos, node);
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if(isFinal) {
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if(haveUniqueValue) {
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if(value!=uniqueValue) {
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return NULL;
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}
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} else {
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uniqueValue=value;
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haveUniqueValue=TRUE;
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}
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} else {
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if(!findUniqueValue(pos+value, haveUniqueValue, uniqueValue)) {
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return NULL;
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}
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haveUniqueValue=TRUE;
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}
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} while(--length>1);
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return pos+1; // ignore the last comparison byte
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}
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UBool
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BytesTrie::findUniqueValue(const uint8_t *pos, UBool haveUniqueValue, int32_t &uniqueValue) {
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for(;;) {
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int32_t node=*pos++;
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if(node<kMinLinearMatch) {
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if(node==0) {
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node=*pos++;
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}
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pos=findUniqueValueFromBranch(pos, node+1, haveUniqueValue, uniqueValue);
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if(pos==NULL) {
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return FALSE;
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}
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haveUniqueValue=TRUE;
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} else if(node<kMinValueLead) {
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// linear-match node
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pos+=node-kMinLinearMatch+1; // Ignore the match bytes.
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} else {
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UBool isFinal=(UBool)(node&kValueIsFinal);
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int32_t value=readValue(pos, node>>1);
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if(haveUniqueValue) {
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if(value!=uniqueValue) {
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return FALSE;
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}
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} else {
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uniqueValue=value;
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haveUniqueValue=TRUE;
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}
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if(isFinal) {
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return TRUE;
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}
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pos=skipValue(pos, node);
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}
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}
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}
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int32_t
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BytesTrie::getNextBytes(ByteSink &out) const {
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const uint8_t *pos=pos_;
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if(pos==NULL) {
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return 0;
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}
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if(remainingMatchLength_>=0) {
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append(out, *pos); // Next byte of a pending linear-match node.
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return 1;
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}
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int32_t node=*pos++;
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if(node>=kMinValueLead) {
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if(node&kValueIsFinal) {
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return 0;
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} else {
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pos=skipValue(pos, node);
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node=*pos++;
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U_ASSERT(node<kMinValueLead);
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}
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}
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if(node<kMinLinearMatch) {
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if(node==0) {
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node=*pos++;
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}
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getNextBranchBytes(pos, ++node, out);
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return node;
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} else {
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// First byte of the linear-match node.
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append(out, *pos);
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return 1;
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}
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}
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void
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BytesTrie::getNextBranchBytes(const uint8_t *pos, int32_t length, ByteSink &out) {
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while(length>kMaxBranchLinearSubNodeLength) {
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++pos; // ignore the comparison byte
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getNextBranchBytes(jumpByDelta(pos), length>>1, out);
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length=length-(length>>1);
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pos=skipDelta(pos);
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}
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do {
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append(out, *pos++);
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pos=skipValue(pos);
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} while(--length>1);
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append(out, *pos);
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}
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void
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BytesTrie::append(ByteSink &out, int c) {
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char ch=(char)c;
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out.Append(&ch, 1);
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}
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U_NAMESPACE_END
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