// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
* Copyright (C) 2010-2011, International Business Machines
* Corporation and others. All Rights Reserved.
*******************************************************************************
* file name: bytestrie.cpp
* encoding: UTF-8
* tab size: 8 (not used)
* indentation:4
*
* created on: 2010sep25
* created by: Markus W. Scherer
*/
#include "unicode/utypes.h"
#include "unicode/bytestream.h"
#include "unicode/bytestrie.h"
#include "unicode/uobject.h"
#include "cmemory.h"
#include "uassert.h"
U_NAMESPACE_BEGIN
BytesTrie::~BytesTrie() {
uprv_free(ownedArray_);
}
// lead byte already shifted right by 1.
int32_t
BytesTrie::readValue(const uint8_t *pos, int32_t leadByte) {
int32_t value;
if(leadByte<kMinTwoByteValueLead) {
value=leadByte-kMinOneByteValueLead;
} else if(leadByte<kMinThreeByteValueLead) {
value=((leadByte-kMinTwoByteValueLead)<<8)|*pos;
} else if(leadByte<kFourByteValueLead) {
value=((leadByte-kMinThreeByteValueLead)<<16)|(pos[0]<<8)|pos[1];
} else if(leadByte==kFourByteValueLead) {
value=(pos[0]<<16)|(pos[1]<<8)|pos[2];
} else {
value=(pos[0]<<24)|(pos[1]<<16)|(pos[2]<<8)|pos[3];
}
return value;
}
const uint8_t *
BytesTrie::jumpByDelta(const uint8_t *pos) {
int32_t delta=*pos++;
if(delta<kMinTwoByteDeltaLead) {
// nothing to do
} else if(delta<kMinThreeByteDeltaLead) {
delta=((delta-kMinTwoByteDeltaLead)<<8)|*pos++;
} else if(delta<kFourByteDeltaLead) {
delta=((delta-kMinThreeByteDeltaLead)<<16)|(pos[0]<<8)|pos[1];
pos+=2;
} else if(delta==kFourByteDeltaLead) {
delta=(pos[0]<<16)|(pos[1]<<8)|pos[2];
pos+=3;
} else {
delta=(pos[0]<<24)|(pos[1]<<16)|(pos[2]<<8)|pos[3];
pos+=4;
}
return pos+delta;
}
UStringTrieResult
BytesTrie::current() const {
const uint8_t *pos=pos_;
if(pos==NULL) {
return USTRINGTRIE_NO_MATCH;
} else {
int32_t node;
return (remainingMatchLength_<0 && (node=*pos)>=kMinValueLead) ?
valueResult(node) : USTRINGTRIE_NO_VALUE;
}
}
UStringTrieResult
BytesTrie::branchNext(const uint8_t *pos, int32_t length, int32_t inByte) {
// Branch according to the current byte.
if(length==0) {
length=*pos++;
}
++length;
// The length of the branch is the number of bytes to select from.
// The data structure encodes a binary search.
while(length>kMaxBranchLinearSubNodeLength) {
if(inByte<*pos++) {
length>>=1;
pos=jumpByDelta(pos);
} else {
length=length-(length>>1);
pos=skipDelta(pos);
}
}
// Drop down to linear search for the last few bytes.
// length>=2 because the loop body above sees length>kMaxBranchLinearSubNodeLength>=3
// and divides length by 2.
do {
if(inByte==*pos++) {
UStringTrieResult result;
int32_t node=*pos;
U_ASSERT(node>=kMinValueLead);
if(node&kValueIsFinal) {
// Leave the final value for getValue() to read.
result=USTRINGTRIE_FINAL_VALUE;
} else {
// Use the non-final value as the jump delta.
++pos;
// int32_t delta=readValue(pos, node>>1);
node>>=1;
int32_t delta;
if(node<kMinTwoByteValueLead) {
delta=node-kMinOneByteValueLead;
} else if(node<kMinThreeByteValueLead) {
delta=((node-kMinTwoByteValueLead)<<8)|*pos++;
} else if(node<kFourByteValueLead) {
delta=((node-kMinThreeByteValueLead)<<16)|(pos[0]<<8)|pos[1];
pos+=2;
} else if(node==kFourByteValueLead) {
delta=(pos[0]<<16)|(pos[1]<<8)|pos[2];
pos+=3;
} else {
delta=(pos[0]<<24)|(pos[1]<<16)|(pos[2]<<8)|pos[3];
pos+=4;
}
// end readValue()
pos+=delta;
node=*pos;
result= node>=kMinValueLead ? valueResult(node) : USTRINGTRIE_NO_VALUE;
}
pos_=pos;
return result;
}
--length;
pos=skipValue(pos);
} while(length>1);
if(inByte==*pos++) {
pos_=pos;
int32_t node=*pos;
return node>=kMinValueLead ? valueResult(node) : USTRINGTRIE_NO_VALUE;
} else {
stop();
return USTRINGTRIE_NO_MATCH;
}
}
UStringTrieResult
BytesTrie::nextImpl(const uint8_t *pos, int32_t inByte) {
for(;;) {
int32_t node=*pos++;
if(node<kMinLinearMatch) {
return branchNext(pos, node, inByte);
} else if(node<kMinValueLead) {
// Match the first of length+1 bytes.
int32_t length=node-kMinLinearMatch; // Actual match length minus 1.
if(inByte==*pos++) {
remainingMatchLength_=--length;
pos_=pos;
return (length<0 && (node=*pos)>=kMinValueLead) ?
valueResult(node) : USTRINGTRIE_NO_VALUE;
} else {
// No match.
break;
}
} else if(node&kValueIsFinal) {
// No further matching bytes.
break;
} else {
// Skip intermediate value.
pos=skipValue(pos, node);
// The next node must not also be a value node.
U_ASSERT(*pos<kMinValueLead);
}
}
stop();
return USTRINGTRIE_NO_MATCH;
}
UStringTrieResult
BytesTrie::next(int32_t inByte) {
const uint8_t *pos=pos_;
if(pos==NULL) {
return USTRINGTRIE_NO_MATCH;
}
if(inByte<0) {
inByte+=0x100;
}
int32_t length=remainingMatchLength_; // Actual remaining match length minus 1.
if(length>=0) {
// Remaining part of a linear-match node.
if(inByte==*pos++) {
remainingMatchLength_=--length;
pos_=pos;
int32_t node;
return (length<0 && (node=*pos)>=kMinValueLead) ?
valueResult(node) : USTRINGTRIE_NO_VALUE;
} else {
stop();
return USTRINGTRIE_NO_MATCH;
}
}
return nextImpl(pos, inByte);
}
UStringTrieResult
BytesTrie::next(const char *s, int32_t sLength) {
if(sLength<0 ? *s==0 : sLength==0) {
// Empty input.
return current();
}
const uint8_t *pos=pos_;
if(pos==NULL) {
return USTRINGTRIE_NO_MATCH;
}
int32_t length=remainingMatchLength_; // Actual remaining match length minus 1.
for(;;) {
// Fetch the next input byte, if there is one.
// Continue a linear-match node without rechecking sLength<0.
int32_t inByte;
if(sLength<0) {
for(;;) {
if((inByte=*s++)==0) {
remainingMatchLength_=length;
pos_=pos;
int32_t node;
return (length<0 && (node=*pos)>=kMinValueLead) ?
valueResult(node) : USTRINGTRIE_NO_VALUE;
}
if(length<0) {
remainingMatchLength_=length;
break;
}
if(inByte!=*pos) {
stop();
return USTRINGTRIE_NO_MATCH;
}
++pos;
--length;
}
} else {
for(;;) {
if(sLength==0) {
remainingMatchLength_=length;
pos_=pos;
int32_t node;
return (length<0 && (node=*pos)>=kMinValueLead) ?
valueResult(node) : USTRINGTRIE_NO_VALUE;
}
inByte=*s++;
--sLength;
if(length<0) {
remainingMatchLength_=length;
break;
}
if(inByte!=*pos) {
stop();
return USTRINGTRIE_NO_MATCH;
}
++pos;
--length;
}
}
for(;;) {
int32_t node=*pos++;
if(node<kMinLinearMatch) {
UStringTrieResult result=branchNext(pos, node, inByte);
if(result==USTRINGTRIE_NO_MATCH) {
return USTRINGTRIE_NO_MATCH;
}
// Fetch the next input byte, if there is one.
if(sLength<0) {
if((inByte=*s++)==0) {
return result;
}
} else {
if(sLength==0) {
return result;
}
inByte=*s++;
--sLength;
}
if(result==USTRINGTRIE_FINAL_VALUE) {
// No further matching bytes.
stop();
return USTRINGTRIE_NO_MATCH;
}
pos=pos_; // branchNext() advanced pos and wrote it to pos_ .
} else if(node<kMinValueLead) {
// Match length+1 bytes.
length=node-kMinLinearMatch; // Actual match length minus 1.
if(inByte!=*pos) {
stop();
return USTRINGTRIE_NO_MATCH;
}
++pos;
--length;
break;
} else if(node&kValueIsFinal) {
// No further matching bytes.
stop();
return USTRINGTRIE_NO_MATCH;
} else {
// Skip intermediate value.
pos=skipValue(pos, node);
// The next node must not also be a value node.
U_ASSERT(*pos<kMinValueLead);
}
}
}
}
const uint8_t *
BytesTrie::findUniqueValueFromBranch(const uint8_t *pos, int32_t length,
UBool haveUniqueValue, int32_t &uniqueValue) {
while(length>kMaxBranchLinearSubNodeLength) {
++pos; // ignore the comparison byte
if(NULL==findUniqueValueFromBranch(jumpByDelta(pos), length>>1, haveUniqueValue, uniqueValue)) {
return NULL;
}
length=length-(length>>1);
pos=skipDelta(pos);
}
do {
++pos; // ignore a comparison byte
// handle its value
int32_t node=*pos++;
UBool isFinal=(UBool)(node&kValueIsFinal);
int32_t value=readValue(pos, node>>1);
pos=skipValue(pos, node);
if(isFinal) {
if(haveUniqueValue) {
if(value!=uniqueValue) {
return NULL;
}
} else {
uniqueValue=value;
haveUniqueValue=TRUE;
}
} else {
if(!findUniqueValue(pos+value, haveUniqueValue, uniqueValue)) {
return NULL;
}
haveUniqueValue=TRUE;
}
} while(--length>1);
return pos+1; // ignore the last comparison byte
}
UBool
BytesTrie::findUniqueValue(const uint8_t *pos, UBool haveUniqueValue, int32_t &uniqueValue) {
for(;;) {
int32_t node=*pos++;
if(node<kMinLinearMatch) {
if(node==0) {
node=*pos++;
}
pos=findUniqueValueFromBranch(pos, node+1, haveUniqueValue, uniqueValue);
if(pos==NULL) {
return FALSE;
}
haveUniqueValue=TRUE;
} else if(node<kMinValueLead) {
// linear-match node
pos+=node-kMinLinearMatch+1; // Ignore the match bytes.
} else {
UBool isFinal=(UBool)(node&kValueIsFinal);
int32_t value=readValue(pos, node>>1);
if(haveUniqueValue) {
if(value!=uniqueValue) {
return FALSE;
}
} else {
uniqueValue=value;
haveUniqueValue=TRUE;
}
if(isFinal) {
return TRUE;
}
pos=skipValue(pos, node);
}
}
}
int32_t
BytesTrie::getNextBytes(ByteSink &out) const {
const uint8_t *pos=pos_;
if(pos==NULL) {
return 0;
}
if(remainingMatchLength_>=0) {
append(out, *pos); // Next byte of a pending linear-match node.
return 1;
}
int32_t node=*pos++;
if(node>=kMinValueLead) {
if(node&kValueIsFinal) {
return 0;
} else {
pos=skipValue(pos, node);
node=*pos++;
U_ASSERT(node<kMinValueLead);
}
}
if(node<kMinLinearMatch) {
if(node==0) {
node=*pos++;
}
getNextBranchBytes(pos, ++node, out);
return node;
} else {
// First byte of the linear-match node.
append(out, *pos);
return 1;
}
}
void
BytesTrie::getNextBranchBytes(const uint8_t *pos, int32_t length, ByteSink &out) {
while(length>kMaxBranchLinearSubNodeLength) {
++pos; // ignore the comparison byte
getNextBranchBytes(jumpByDelta(pos), length>>1, out);
length=length-(length>>1);
pos=skipDelta(pos);
}
do {
append(out, *pos++);
pos=skipValue(pos);
} while(--length>1);
append(out, *pos);
}
void
BytesTrie::append(ByteSink &out, int c) {
char ch=(char)c;
out.Append(&ch, 1);
}
U_NAMESPACE_END