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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
* Copyright (C) 2010-2012, International Business Machines
* Corporation and others. All Rights Reserved.
*******************************************************************************
* file name: bytestrieiterator.cpp
* encoding: UTF-8
* tab size: 8 (not used)
* indentation:4
*
* created on: 2010nov03
* created by: Markus W. Scherer
*/
#include "unicode/utypes.h"
#include "unicode/bytestrie.h"
#include "unicode/stringpiece.h"
#include "charstr.h"
#include "uvectr32.h"
U_NAMESPACE_BEGIN
BytesTrie::Iterator::Iterator(const void *trieBytes, int32_t maxStringLength,
UErrorCode &errorCode)
: bytes_(static_cast<const uint8_t *>(trieBytes)),
pos_(bytes_), initialPos_(bytes_),
remainingMatchLength_(-1), initialRemainingMatchLength_(-1),
str_(nullptr), maxLength_(maxStringLength), value_(0), stack_(nullptr) {
if(U_FAILURE(errorCode)) {
return;
}
// str_ and stack_ are pointers so that it's easy to turn bytestrie.h into
// a public API header for which we would want it to depend only on
// other public headers.
// Unlike BytesTrie itself, its Iterator performs memory allocations anyway
// via the CharString and UVector32 implementations, so this additional
// cost is minimal.
str_=new CharString();
stack_=new UVector32(errorCode);
if(U_SUCCESS(errorCode) && (str_==nullptr || stack_==nullptr)) {
errorCode=U_MEMORY_ALLOCATION_ERROR;
}
}
BytesTrie::Iterator::Iterator(const BytesTrie &trie, int32_t maxStringLength,
UErrorCode &errorCode)
: bytes_(trie.bytes_), pos_(trie.pos_), initialPos_(trie.pos_),
remainingMatchLength_(trie.remainingMatchLength_),
initialRemainingMatchLength_(trie.remainingMatchLength_),
str_(nullptr), maxLength_(maxStringLength), value_(0), stack_(nullptr) {
if(U_FAILURE(errorCode)) {
return;
}
str_=new CharString();
stack_=new UVector32(errorCode);
if(U_FAILURE(errorCode)) {
return;
}
if(str_==nullptr || stack_==nullptr) {
errorCode=U_MEMORY_ALLOCATION_ERROR;
return;
}
int32_t length=remainingMatchLength_; // Actual remaining match length minus 1.
if(length>=0) {
// Pending linear-match node, append remaining bytes to str_.
++length;
if(maxLength_>0 && length>maxLength_) {
length=maxLength_; // This will leave remainingMatchLength>=0 as a signal.
}
str_->append(reinterpret_cast<const char *>(pos_), length, errorCode);
pos_+=length;
remainingMatchLength_-=length;
}
}
BytesTrie::Iterator::~Iterator() {
delete str_;
delete stack_;
}
BytesTrie::Iterator &
BytesTrie::Iterator::reset() {
pos_=initialPos_;
remainingMatchLength_=initialRemainingMatchLength_;
int32_t length=remainingMatchLength_+1; // Remaining match length.
if(maxLength_>0 && length>maxLength_) {
length=maxLength_;
}
str_->truncate(length);
pos_+=length;
remainingMatchLength_-=length;
stack_->setSize(0);
return *this;
}
UBool
BytesTrie::Iterator::hasNext() const { return pos_!=nullptr || !stack_->isEmpty(); }
UBool
BytesTrie::Iterator::next(UErrorCode &errorCode) {
if(U_FAILURE(errorCode)) {
return false;
}
const uint8_t *pos=pos_;
if(pos==nullptr) {
if(stack_->isEmpty()) {
return false;
}
// Pop the state off the stack and continue with the next outbound edge of
// the branch node.
int32_t stackSize=stack_->size();
int32_t length=stack_->elementAti(stackSize-1);
pos=bytes_+stack_->elementAti(stackSize-2);
stack_->setSize(stackSize-2);
str_->truncate(length&0xffff);
length=(int32_t)((uint32_t)length>>16);
if(length>1) {
pos=branchNext(pos, length, errorCode);
if(pos==nullptr) {
return true; // Reached a final value.
}
} else {
str_->append((char)*pos++, errorCode);
}
}
if(remainingMatchLength_>=0) {
// We only get here if we started in a pending linear-match node
// with more than maxLength remaining bytes.
return truncateAndStop();
}
for(;;) {
int32_t node=*pos++;
if(node>=kMinValueLead) {
// Deliver value for the byte sequence so far.
UBool isFinal=(UBool)(node&kValueIsFinal);
value_=readValue(pos, node>>1);
if(isFinal || (maxLength_>0 && str_->length()==maxLength_)) {
pos_=nullptr;
} else {
pos_=skipValue(pos, node);
}
return true;
}
if(maxLength_>0 && str_->length()==maxLength_) {
return truncateAndStop();
}
if(node<kMinLinearMatch) {
if(node==0) {
node=*pos++;
}
pos=branchNext(pos, node+1, errorCode);
if(pos==nullptr) {
return true; // Reached a final value.
}
} else {
// Linear-match node, append length bytes to str_.
int32_t length=node-kMinLinearMatch+1;
if(maxLength_>0 && str_->length()+length>maxLength_) {
str_->append(reinterpret_cast<const char *>(pos),
maxLength_-str_->length(), errorCode);
return truncateAndStop();
}
str_->append(reinterpret_cast<const char *>(pos), length, errorCode);
pos+=length;
}
}
}
StringPiece
BytesTrie::Iterator::getString() const {
return str_ == nullptr ? StringPiece() : str_->toStringPiece();
}
UBool
BytesTrie::Iterator::truncateAndStop() {
pos_=nullptr;
value_=-1; // no real value for str
return true;
}
// Branch node, needs to take the first outbound edge and push state for the rest.
const uint8_t *
BytesTrie::Iterator::branchNext(const uint8_t *pos, int32_t length, UErrorCode &errorCode) {
while(length>kMaxBranchLinearSubNodeLength) {
++pos; // ignore the comparison byte
// Push state for the greater-or-equal edge.
stack_->addElement((int32_t)(skipDelta(pos)-bytes_), errorCode);
stack_->addElement(((length-(length>>1))<<16)|str_->length(), errorCode);
// Follow the less-than edge.
length>>=1;
pos=jumpByDelta(pos);
}
// List of key-value pairs where values are either final values or jump deltas.
// Read the first (key, value) pair.
uint8_t trieByte=*pos++;
int32_t node=*pos++;
UBool isFinal=(UBool)(node&kValueIsFinal);
int32_t value=readValue(pos, node>>1);
pos=skipValue(pos, node);
stack_->addElement((int32_t)(pos-bytes_), errorCode);
stack_->addElement(((length-1)<<16)|str_->length(), errorCode);
str_->append((char)trieByte, errorCode);
if(isFinal) {
pos_=nullptr;
value_=value;
return nullptr;
} else {
return pos+value;
}
}
U_NAMESPACE_END
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