package org.apache.lucene.util.automaton;
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import org.apache.lucene.util.RamUsageEstimator;
import org.apache.lucene.util.ArrayUtil;
import java.util.List;
import java.util.ArrayList;
// TODO
// - do we really need the .bits...? if not we can make util in UnicodeUtil to convert 1 char into a BytesRef
final class UTF32ToUTF8 {
// Unicode boundaries for UTF8 bytes 1,2,3,4
private static final int[] startCodes = new int[] {0, 128, 2048, 65536};
private static final int[] endCodes = new int[] {127, 2047, 65535, 1114111};
static int[] MASKS = new int[32];
static {
int v = 2;
for(int i=0;i<32;i++) {
MASKS[i] = v-1;
v *= 2;
}
}
// Represents one of the N utf8 bytes that (in sequence)
// define a code point. value is the byte value; bits is
// how many bits are "used" by utf8 at that byte
private static class UTF8Byte {
int value; // TODO: change to byte
byte bits;
}
// Holds a single code point, as a sequence of 1-4 utf8 bytes:
// TODO: maybe move to UnicodeUtil?
private static class UTF8Sequence {
private final UTF8Byte[] bytes;
private int len;
public UTF8Sequence() {
bytes = new UTF8Byte[4];
for(int i=0;i<4;i++) {
bytes[i] = new UTF8Byte();
}
}
public int byteAt(int idx) {
return bytes[idx].value;
}
public int numBits(int idx) {
return bytes[idx].bits;
}
private void set(int code) {
if (code < 128) {
// 0xxxxxxx
bytes[0].value = code;
bytes[0].bits = 7;
len = 1;
} else if (code < 2048) {
// 110yyyxx 10xxxxxx
bytes[0].value = (6 << 5) | (code >> 6);
bytes[0].bits = 5;
setRest(code, 1);
len = 2;
} else if (code < 65536) {
// 1110yyyy 10yyyyxx 10xxxxxx
bytes[0].value = (14 << 4) | (code >> 12);
bytes[0].bits = 4;
setRest(code, 2);
len = 3;
} else {
// 11110zzz 10zzyyyy 10yyyyxx 10xxxxxx
bytes[0].value = (30 << 3) | (code >> 18);
bytes[0].bits = 3;
setRest(code, 3);
len = 4;
}
}
private void setRest(int code, int numBytes) {
for(int i=0;i<numBytes;i++) {
bytes[numBytes-i].value = 128 | (code & MASKS[5]);
bytes[numBytes-i].bits = 6;
code = code >> 6;
}
}
public String toString() {
StringBuilder b = new StringBuilder();
for(int i=0;i<len;i++) {
if (i > 0) {
b.append(' ');
}
b.append(Integer.toBinaryString(bytes[i].value));
}
return b.toString();
}
}
private final UTF8Sequence startUTF8 = new UTF8Sequence();
private final UTF8Sequence endUTF8 = new UTF8Sequence();
private final UTF8Sequence tmpUTF8a = new UTF8Sequence();
private final UTF8Sequence tmpUTF8b = new UTF8Sequence();
// Builds necessary utf8 edges between start & end
void convertOneEdge(State start, State end, int startCodePoint, int endCodePoint) {
startUTF8.set(startCodePoint);
endUTF8.set(endCodePoint);
//System.out.println("start = " + startUTF8);
//System.out.println(" end = " + endUTF8);
build(start, end, startUTF8, endUTF8, 0);
}
private void build(State start, State end, UTF8Sequence startUTF8, UTF8Sequence endUTF8, int upto) {
// Break into start, middle, end:
if (startUTF8.byteAt(upto) == endUTF8.byteAt(upto)) {
// Degen case: lead with the same byte:
if (upto == startUTF8.len-1 && upto == endUTF8.len-1) {
// Super degen: just single edge, one UTF8 byte:
start.addTransition(new Transition(startUTF8.byteAt(upto), endUTF8.byteAt(upto), end));
return;
} else {
assert startUTF8.len > upto+1;
assert endUTF8.len > upto+1;
State n = newUTF8State();
// Single value leading edge
start.addTransition(new Transition(startUTF8.byteAt(upto), n)); // type=single
// Recurse for the rest
build(n, end, startUTF8, endUTF8, 1+upto);
}
} else if (startUTF8.len == endUTF8.len) {
if (upto == startUTF8.len-1) {
start.addTransition(new Transition(startUTF8.byteAt(upto), endUTF8.byteAt(upto), end)); // type=startend
} else {
start(start, end, startUTF8, upto, false);
if (endUTF8.byteAt(upto) - startUTF8.byteAt(upto) > 1) {
// There is a middle
all(start, end, startUTF8.byteAt(upto)+1, endUTF8.byteAt(upto)-1, startUTF8.len-upto-1);
}
end(start, end, endUTF8, upto, false);
}
} else {
// start
start(start, end, startUTF8, upto, true);
// possibly middle, spanning multiple num bytes
int byteCount = 1+startUTF8.len-upto;
final int limit = endUTF8.len-upto;
while (byteCount < limit) {
// wasteful: we only need first byte, and, we should
// statically encode this first byte:
tmpUTF8a.set(startCodes[byteCount-1]);
tmpUTF8b.set(endCodes[byteCount-1]);
all(start, end,
tmpUTF8a.byteAt(0),
tmpUTF8b.byteAt(0),
tmpUTF8a.len - 1);
byteCount++;
}
// end
end(start, end, endUTF8, upto, true);
}
}
private void start(State start, State end, UTF8Sequence utf8, int upto, boolean doAll) {
if (upto == utf8.len-1) {
// Done recursing
start.addTransition(new Transition(utf8.byteAt(upto), utf8.byteAt(upto) | MASKS[utf8.numBits(upto)-1], end)); // type=start
} else {
State n = newUTF8State();
start.addTransition(new Transition(utf8.byteAt(upto), n)); // type=start
start(n, end, utf8, 1+upto, true);
int endCode = utf8.byteAt(upto) | MASKS[utf8.numBits(upto)-1];
if (doAll && utf8.byteAt(upto) != endCode) {
all(start, end, utf8.byteAt(upto)+1, endCode, utf8.len-upto-1);
}
}
}
private void end(State start, State end, UTF8Sequence utf8, int upto, boolean doAll) {
if (upto == utf8.len-1) {
// Done recursing
start.addTransition(new Transition(utf8.byteAt(upto) & (~MASKS[utf8.numBits(upto)-1]), utf8.byteAt(upto), end)); // type=end
} else {
final int startCode;
if (utf8.numBits(upto) == 5) {
// special case -- avoid created unused edges (utf8
// doesn't accept certain byte sequences) -- there
// are other cases we could optimize too:
startCode = 194;
} else {
startCode = utf8.byteAt(upto) & (~MASKS[utf8.numBits(upto)-1]);
}
if (doAll && utf8.byteAt(upto) != startCode) {
all(start, end, startCode, utf8.byteAt(upto)-1, utf8.len-upto-1);
}
State n = newUTF8State();
start.addTransition(new Transition(utf8.byteAt(upto), n)); // type=end
end(n, end, utf8, 1+upto, true);
}
}
private void all(State start, State end, int startCode, int endCode, int left) {
if (left == 0) {
start.addTransition(new Transition(startCode, endCode, end)); // type=all
} else {
State lastN = newUTF8State();
start.addTransition(new Transition(startCode, endCode, lastN)); // type=all
while (left > 1) {
State n = newUTF8State();
lastN.addTransition(new Transition(128, 191, n)); // type=all*
left--;
lastN = n;
}
lastN.addTransition(new Transition(128, 191, end)); // type = all*
}
}
private State[] utf8States;
private int utf8StateCount;
/** Converts an incoming utf32 automaton to an equivalent
* utf8 one. The incoming automaton need not be
* deterministic. Note that the returned automaton will
* not in general be deterministic, so you must
* determinize it if that's needed. */
public Automaton convert(Automaton utf32) {
if (utf32.isSingleton()) {
utf32 = utf32.cloneExpanded();
}
State[] map = new State[utf32.getNumberedStates().length];
List<State> pending = new ArrayList<State>();
State utf32State = utf32.getInitialState();
pending.add(utf32State);
Automaton utf8 = new Automaton();
utf8.setDeterministic(false);
State utf8State = utf8.getInitialState();
utf8States = new State[5];
utf8StateCount = 0;
utf8State.number = utf8StateCount;
utf8States[utf8StateCount] = utf8State;
utf8StateCount++;
utf8State.setAccept(utf32State.isAccept());
map[utf32State.number] = utf8State;
while(pending.size() != 0) {
utf32State = pending.remove(pending.size()-1);
utf8State = map[utf32State.number];
for(int i=0;i<utf32State.numTransitions;i++) {
final Transition t = utf32State.transitionsArray[i];
final State destUTF32 = t.to;
State destUTF8 = map[destUTF32.number];
if (destUTF8 == null) {
destUTF8 = newUTF8State();
destUTF8.accept = destUTF32.accept;
map[destUTF32.number] = destUTF8;
pending.add(destUTF32);
}
convertOneEdge(utf8State, destUTF8, t.min, t.max);
}
}
utf8.setNumberedStates(utf8States, utf8StateCount);
return utf8;
}
private State newUTF8State() {
State s = new State();
if (utf8StateCount == utf8States.length) {
final State[] newArray = new State[ArrayUtil.oversize(1+utf8StateCount, RamUsageEstimator.NUM_BYTES_OBJ_REF)];
System.arraycopy(utf8States, 0, newArray, 0, utf8StateCount);
utf8States = newArray;
}
utf8States[utf8StateCount] = s;
s.number = utf8StateCount;
utf8StateCount++;
return s;
}
public static void main(String[] args) {
final int startCode = Integer.parseInt(args[0]);
final int endCode = Integer.parseInt(args[1]);
Automaton a = new Automaton();
State start = a.getInitialState();
State end = new State();
end.setAccept(true);
UTF32ToUTF8 converter = new UTF32ToUTF8();
converter.convertOneEdge(start, end, startCode, endCode);
}
}