package org.apache.lucene.util.fst;
/*
* 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 java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import org.apache.lucene.codecs.CodecUtil;
import org.apache.lucene.store.ByteArrayDataOutput;
import org.apache.lucene.store.DataInput;
import org.apache.lucene.store.DataOutput;
import org.apache.lucene.store.InputStreamDataInput;
import org.apache.lucene.store.OutputStreamDataOutput;
import org.apache.lucene.store.RAMOutputStream;
import org.apache.lucene.util.ArrayUtil;
import org.apache.lucene.util.Constants;
import org.apache.lucene.util.IOUtils;
import org.apache.lucene.util.IntsRef;
import org.apache.lucene.util.PriorityQueue;
import org.apache.lucene.util.fst.Builder.UnCompiledNode;
import org.apache.lucene.util.packed.GrowableWriter;
import org.apache.lucene.util.packed.PackedInts;
//import java.io.Writer;
//import java.io.OutputStreamWriter;
// TODO: break this into WritableFST and ReadOnlyFST.. then
// we can have subclasses of ReadOnlyFST to handle the
// different byte[] level encodings (packed or
// not)... and things like nodeCount, arcCount are read only
// TODO: if FST is pure prefix trie we can do a more compact
// job, ie, once we are at a 'suffix only', just store the
// completion labels as a string not as a series of arcs.
// NOTE: while the FST is able to represent a non-final
// dead-end state (NON_FINAL_END_NODE=0), the layers above
// (FSTEnum, Util) have problems with this!!
/** Represents an finite state machine (FST), using a
* compact byte[] format.
* <p> The format is similar to what's used by Morfologik
* (http://sourceforge.net/projects/morfologik).
*
* <p> See the {@link org.apache.lucene.util.fst package
* documentation} for some simple examples.
*
* @lucene.experimental
*/
public final class FST<T> {
/** Specifies allowed range of each int input label for
* this FST. */
public static enum INPUT_TYPE {BYTE1, BYTE2, BYTE4};
public final INPUT_TYPE inputType;
final static int BIT_FINAL_ARC = 1 << 0;
final static int BIT_LAST_ARC = 1 << 1;
final static int BIT_TARGET_NEXT = 1 << 2;
// TODO: we can free up a bit if we can nuke this:
final static int BIT_STOP_NODE = 1 << 3;
final static int BIT_ARC_HAS_OUTPUT = 1 << 4;
final static int BIT_ARC_HAS_FINAL_OUTPUT = 1 << 5;
// Arcs are stored as fixed-size (per entry) array, so
// that we can find an arc using binary search. We do
// this when number of arcs is > NUM_ARCS_ARRAY:
// If set, the target node is delta coded vs current
// position:
private final static int BIT_TARGET_DELTA = 1 << 6;
// We use this as a marker (because this one flag is
// illegal by itself ...):
private final static byte ARCS_AS_FIXED_ARRAY = BIT_ARC_HAS_FINAL_OUTPUT;
/**
* @see #shouldExpand(UnCompiledNode)
*/
final static int FIXED_ARRAY_SHALLOW_DISTANCE = 3; // 0 => only root node.
/**
* @see #shouldExpand(UnCompiledNode)
*/
final static int FIXED_ARRAY_NUM_ARCS_SHALLOW = 5;
/**
* @see #shouldExpand(UnCompiledNode)
*/
final static int FIXED_ARRAY_NUM_ARCS_DEEP = 10;
private int[] bytesPerArc = new int[0];
// Increment version to change it
private final static String FILE_FORMAT_NAME = "FST";
private final static int VERSION_START = 0;
/** Changed numBytesPerArc for array'd case from byte to int. */
private final static int VERSION_INT_NUM_BYTES_PER_ARC = 1;
/** Write BYTE2 labels as 2-byte short, not vInt. */
private final static int VERSION_SHORT_BYTE2_LABELS = 2;
/** Added optional packed format. */
private final static int VERSION_PACKED = 3;
/** Changed from int to vInt for encoding arc targets.
* Also changed maxBytesPerArc from int to vInt in the array case. */
private final static int VERSION_VINT_TARGET = 4;
private final static int VERSION_CURRENT = VERSION_VINT_TARGET;
// Never serialized; just used to represent the virtual
// final node w/ no arcs:
private final static long FINAL_END_NODE = -1;
// Never serialized; just used to represent the virtual
// non-final node w/ no arcs:
private final static long NON_FINAL_END_NODE = 0;
// if non-null, this FST accepts the empty string and
// produces this output
T emptyOutput;
final BytesStore bytes;
private long startNode = -1;
public final Outputs<T> outputs;
// Used for the BIT_TARGET_NEXT optimization (whereby
// instead of storing the address of the target node for
// a given arc, we mark a single bit noting that the next
// node in the byte[] is the target node):
private long lastFrozenNode;
private final T NO_OUTPUT;
public long nodeCount;
public long arcCount;
public long arcWithOutputCount;
private final boolean packed;
private PackedInts.Reader nodeRefToAddress;
/** If arc has this label then that arc is final/accepted */
public static final int END_LABEL = -1;
private final boolean allowArrayArcs;
private Arc<T> cachedRootArcs[];
private Arc<T> assertingCachedRootArcs[]; // only set wit assert
/** Represents a single arc. */
public final static class Arc<T> {
public int label;
public T output;
// From node (ord or address); currently only used when
// building an FST w/ willPackFST=true:
long node;
/** To node (ord or address) */
public long target;
byte flags;
public T nextFinalOutput;
// address (into the byte[]), or ord/address if label == END_LABEL
long nextArc;
// This is non-zero if current arcs are fixed array:
long posArcsStart;
int bytesPerArc;
int arcIdx;
int numArcs;
/** Returns this */
public Arc<T> copyFrom(Arc<T> other) {
node = other.node;
label = other.label;
target = other.target;
flags = other.flags;
output = other.output;
nextFinalOutput = other.nextFinalOutput;
nextArc = other.nextArc;
bytesPerArc = other.bytesPerArc;
if (bytesPerArc != 0) {
posArcsStart = other.posArcsStart;
arcIdx = other.arcIdx;
numArcs = other.numArcs;
}
return this;
}
boolean flag(int flag) {
return FST.flag(flags, flag);
}
public boolean isLast() {
return flag(BIT_LAST_ARC);
}
public boolean isFinal() {
return flag(BIT_FINAL_ARC);
}
@Override
public String toString() {
StringBuilder b = new StringBuilder();
b.append("node=" + node);
b.append(" target=" + target);
b.append(" label=" + label);
if (flag(BIT_LAST_ARC)) {
b.append(" last");
}
if (flag(BIT_FINAL_ARC)) {
b.append(" final");
}
if (flag(BIT_TARGET_NEXT)) {
b.append(" targetNext");
}
if (flag(BIT_ARC_HAS_OUTPUT)) {
b.append(" output=" + output);
}
if (flag(BIT_ARC_HAS_FINAL_OUTPUT)) {
b.append(" nextFinalOutput=" + nextFinalOutput);
}
if (bytesPerArc != 0) {
b.append(" arcArray(idx=" + arcIdx + " of " + numArcs + ")");
}
return b.toString();
}
};
private static boolean flag(int flags, int bit) {
return (flags & bit) != 0;
}
private GrowableWriter nodeAddress;
// TODO: we could be smarter here, and prune periodically
// as we go; high in-count nodes will "usually" become
// clear early on:
private GrowableWriter inCounts;
private final int version;
// make a new empty FST, for building; Builder invokes
// this ctor
FST(INPUT_TYPE inputType, Outputs<T> outputs, boolean willPackFST, float acceptableOverheadRatio, boolean allowArrayArcs, int bytesPageBits) {
this.inputType = inputType;
this.outputs = outputs;
this.allowArrayArcs = allowArrayArcs;
version = VERSION_CURRENT;
bytes = new BytesStore(bytesPageBits);
// pad: ensure no node gets address 0 which is reserved to mean
// the stop state w/ no arcs
bytes.writeByte((byte) 0);
NO_OUTPUT = outputs.getNoOutput();
if (willPackFST) {
nodeAddress = new GrowableWriter(15, 8, acceptableOverheadRatio);
inCounts = new GrowableWriter(1, 8, acceptableOverheadRatio);
} else {
nodeAddress = null;
inCounts = null;
}
emptyOutput = null;
packed = false;
nodeRefToAddress = null;
}
public static final int DEFAULT_MAX_BLOCK_BITS = Constants.JRE_IS_64BIT ? 30 : 28;
/** Load a previously saved FST. */
public FST(DataInput in, Outputs<T> outputs) throws IOException {
this(in, outputs, DEFAULT_MAX_BLOCK_BITS);
}
/** Load a previously saved FST; maxBlockBits allows you to
* control the size of the byte[] pages used to hold the FST bytes. */
public FST(DataInput in, Outputs<T> outputs, int maxBlockBits) throws IOException {
this.outputs = outputs;
if (maxBlockBits < 1 || maxBlockBits > 30) {
throw new IllegalArgumentException("maxBlockBits should be 1 .. 30; got " + maxBlockBits);
}
// NOTE: only reads most recent format; we don't have
// back-compat promise for FSTs (they are experimental):
version = CodecUtil.checkHeader(in, FILE_FORMAT_NAME, VERSION_PACKED, VERSION_VINT_TARGET);
packed = in.readByte() == 1;
if (in.readByte() == 1) {
// accepts empty string
// 1 KB blocks:
BytesStore emptyBytes = new BytesStore(10);
int numBytes = in.readVInt();
emptyBytes.copyBytes(in, numBytes);
// De-serialize empty-string output:
BytesReader reader;
if (packed) {
reader = emptyBytes.getForwardReader();
} else {
reader = emptyBytes.getReverseReader();
// NoOutputs uses 0 bytes when writing its output,
// so we have to check here else BytesStore gets
// angry:
if (numBytes > 0) {
reader.setPosition(numBytes-1);
}
}
emptyOutput = outputs.readFinalOutput(reader);
} else {
emptyOutput = null;
}
final byte t = in.readByte();
switch(t) {
case 0:
inputType = INPUT_TYPE.BYTE1;
break;
case 1:
inputType = INPUT_TYPE.BYTE2;
break;
case 2:
inputType = INPUT_TYPE.BYTE4;
break;
default:
throw new IllegalStateException("invalid input type " + t);
}
if (packed) {
nodeRefToAddress = PackedInts.getReader(in);
} else {
nodeRefToAddress = null;
}
startNode = in.readVLong();
nodeCount = in.readVLong();
arcCount = in.readVLong();
arcWithOutputCount = in.readVLong();
long numBytes = in.readVLong();
bytes = new BytesStore(in, numBytes, 1<<maxBlockBits);
NO_OUTPUT = outputs.getNoOutput();
cacheRootArcs();
// NOTE: bogus because this is only used during
// building; we need to break out mutable FST from
// immutable
allowArrayArcs = false;
/*
if (bytes.length == 665) {
Writer w = new OutputStreamWriter(new FileOutputStream("out.dot"), "UTF-8");
Util.toDot(this, w, false, false);
w.close();
System.out.println("Wrote FST to out.dot");
}
*/
}
public INPUT_TYPE getInputType() {
return inputType;
}
/** Returns bytes used to represent the FST */
public long sizeInBytes() {
long size = bytes.getPosition();
if (packed) {
size += nodeRefToAddress.ramBytesUsed();
} else if (nodeAddress != null) {
size += nodeAddress.ramBytesUsed();
size += inCounts.ramBytesUsed();
}
return size;
}
void finish(long newStartNode) throws IOException {
if (startNode != -1) {
throw new IllegalStateException("already finished");
}
if (newStartNode == FINAL_END_NODE && emptyOutput != null) {
newStartNode = 0;
}
startNode = newStartNode;
bytes.finish();
cacheRootArcs();
}
private long getNodeAddress(long node) {
if (nodeAddress != null) {
// Deref
return nodeAddress.get((int) node);
} else {
// Straight
return node;
}
}
// Caches first 128 labels
@SuppressWarnings({"rawtypes","unchecked"})
private void cacheRootArcs() throws IOException {
cachedRootArcs = (Arc<T>[]) new Arc[0x80];
readRootArcs(cachedRootArcs);
assert setAssertingRootArcs(cachedRootArcs);
assert assertRootArcs();
}
public void readRootArcs(Arc<T>[] arcs) throws IOException {
final Arc<T> arc = new Arc<T>();
getFirstArc(arc);
final BytesReader in = getBytesReader();
if (targetHasArcs(arc)) {
readFirstRealTargetArc(arc.target, arc, in);
while(true) {
assert arc.label != END_LABEL;
if (arc.label < cachedRootArcs.length) {
arcs[arc.label] = new Arc<T>().copyFrom(arc);
} else {
break;
}
if (arc.isLast()) {
break;
}
readNextRealArc(arc, in);
}
}
}
@SuppressWarnings({"rawtypes","unchecked"})
private boolean setAssertingRootArcs(Arc<T>[] arcs) throws IOException {
assertingCachedRootArcs = (Arc<T>[]) new Arc[arcs.length];
readRootArcs(assertingCachedRootArcs);
return true;
}
private boolean assertRootArcs() {
assert cachedRootArcs != null;
assert assertingCachedRootArcs != null;
for (int i = 0; i < cachedRootArcs.length; i++) {
final Arc<T> root = cachedRootArcs[i];
final Arc<T> asserting = assertingCachedRootArcs[i];
if (root != null) {
assert root.arcIdx == asserting.arcIdx;
assert root.bytesPerArc == asserting.bytesPerArc;
assert root.flags == asserting.flags;
assert root.label == asserting.label;
assert root.nextArc == asserting.nextArc;
assert root.nextFinalOutput.equals(asserting.nextFinalOutput);
assert root.node == asserting.node;
assert root.numArcs == asserting.numArcs;
assert root.output.equals(asserting.output);
assert root.posArcsStart == asserting.posArcsStart;
assert root.target == asserting.target;
} else {
assert root == null && asserting == null;
}
}
return true;
}
public T getEmptyOutput() {
return emptyOutput;
}
void setEmptyOutput(T v) throws IOException {
if (emptyOutput != null) {
emptyOutput = outputs.merge(emptyOutput, v);
} else {
emptyOutput = v;
}
}
public void save(DataOutput out) throws IOException {
if (startNode == -1) {
throw new IllegalStateException("call finish first");
}
if (nodeAddress != null) {
throw new IllegalStateException("cannot save an FST pre-packed FST; it must first be packed");
}
if (packed && !(nodeRefToAddress instanceof PackedInts.Mutable)) {
throw new IllegalStateException("cannot save a FST which has been loaded from disk ");
}
CodecUtil.writeHeader(out, FILE_FORMAT_NAME, VERSION_CURRENT);
if (packed) {
out.writeByte((byte) 1);
} else {
out.writeByte((byte) 0);
}
// TODO: really we should encode this as an arc, arriving
// to the root node, instead of special casing here:
if (emptyOutput != null) {
// Accepts empty string
out.writeByte((byte) 1);
// Serialize empty-string output:
RAMOutputStream ros = new RAMOutputStream();
outputs.writeFinalOutput(emptyOutput, ros);
byte[] emptyOutputBytes = new byte[(int) ros.getFilePointer()];
ros.writeTo(emptyOutputBytes, 0);
if (!packed) {
// reverse
final int stopAt = emptyOutputBytes.length/2;
int upto = 0;
while(upto < stopAt) {
final byte b = emptyOutputBytes[upto];
emptyOutputBytes[upto] = emptyOutputBytes[emptyOutputBytes.length-upto-1];
emptyOutputBytes[emptyOutputBytes.length-upto-1] = b;
upto++;
}
}
out.writeVInt(emptyOutputBytes.length);
out.writeBytes(emptyOutputBytes, 0, emptyOutputBytes.length);
} else {
out.writeByte((byte) 0);
}
final byte t;
if (inputType == INPUT_TYPE.BYTE1) {
t = 0;
} else if (inputType == INPUT_TYPE.BYTE2) {
t = 1;
} else {
t = 2;
}
out.writeByte(t);
if (packed) {
((PackedInts.Mutable) nodeRefToAddress).save(out);
}
out.writeVLong(startNode);
out.writeVLong(nodeCount);
out.writeVLong(arcCount);
out.writeVLong(arcWithOutputCount);
long numBytes = bytes.getPosition();
out.writeVLong(numBytes);
bytes.writeTo(out);
}
/**
* Writes an automaton to a file.
*/
public void save(final File file) throws IOException {
boolean success = false;
OutputStream os = new BufferedOutputStream(new FileOutputStream(file));
try {
save(new OutputStreamDataOutput(os));
success = true;
} finally {
if (success) {
IOUtils.close(os);
} else {
IOUtils.closeWhileHandlingException(os);
}
}
}
/**
* Reads an automaton from a file.
*/
public static <T> FST<T> read(File file, Outputs<T> outputs) throws IOException {
InputStream is = new BufferedInputStream(new FileInputStream(file));
boolean success = false;
try {
FST<T> fst = new FST<T>(new InputStreamDataInput(is), outputs);
success = true;
return fst;
} finally {
if (success) {
IOUtils.close(is);
} else {
IOUtils.closeWhileHandlingException(is);
}
}
}
private void writeLabel(DataOutput out, int v) throws IOException {
assert v >= 0: "v=" + v;
if (inputType == INPUT_TYPE.BYTE1) {
assert v <= 255: "v=" + v;
out.writeByte((byte) v);
} else if (inputType == INPUT_TYPE.BYTE2) {
assert v <= 65535: "v=" + v;
out.writeShort((short) v);
} else {
out.writeVInt(v);
}
}
int readLabel(DataInput in) throws IOException {
final int v;
if (inputType == INPUT_TYPE.BYTE1) {
// Unsigned byte:
v = in.readByte()&0xFF;
} else if (inputType == INPUT_TYPE.BYTE2) {
// Unsigned short:
v = in.readShort()&0xFFFF;
} else {
v = in.readVInt();
}
return v;
}
/** returns true if the node at this address has any
* outgoing arcs */
public static<T> boolean targetHasArcs(Arc<T> arc) {
return arc.target > 0;
}
// serializes new node by appending its bytes to the end
// of the current byte[]
long addNode(Builder.UnCompiledNode<T> nodeIn) throws IOException {
//System.out.println("FST.addNode pos=" + bytes.getPosition() + " numArcs=" + nodeIn.numArcs);
if (nodeIn.numArcs == 0) {
if (nodeIn.isFinal) {
return FINAL_END_NODE;
} else {
return NON_FINAL_END_NODE;
}
}
final long startAddress = bytes.getPosition();
//System.out.println(" startAddr=" + startAddress);
final boolean doFixedArray = shouldExpand(nodeIn);
if (doFixedArray) {
//System.out.println(" fixedArray");
if (bytesPerArc.length < nodeIn.numArcs) {
bytesPerArc = new int[ArrayUtil.oversize(nodeIn.numArcs, 1)];
}
}
arcCount += nodeIn.numArcs;
final int lastArc = nodeIn.numArcs-1;
long lastArcStart = bytes.getPosition();
int maxBytesPerArc = 0;
for(int arcIdx=0;arcIdx<nodeIn.numArcs;arcIdx++) {
final Builder.Arc<T> arc = nodeIn.arcs[arcIdx];
final Builder.CompiledNode target = (Builder.CompiledNode) arc.target;
int flags = 0;
//System.out.println(" arc " + arcIdx + " label=" + arc.label + " -> target=" + target.node);
if (arcIdx == lastArc) {
flags += BIT_LAST_ARC;
}
if (lastFrozenNode == target.node && !doFixedArray) {
// TODO: for better perf (but more RAM used) we
// could avoid this except when arc is "near" the
// last arc:
flags += BIT_TARGET_NEXT;
}
if (arc.isFinal) {
flags += BIT_FINAL_ARC;
if (arc.nextFinalOutput != NO_OUTPUT) {
flags += BIT_ARC_HAS_FINAL_OUTPUT;
}
} else {
assert arc.nextFinalOutput == NO_OUTPUT;
}
boolean targetHasArcs = target.node > 0;
if (!targetHasArcs) {
flags += BIT_STOP_NODE;
} else if (inCounts != null) {
inCounts.set((int) target.node, inCounts.get((int) target.node) + 1);
}
if (arc.output != NO_OUTPUT) {
flags += BIT_ARC_HAS_OUTPUT;
}
bytes.writeByte((byte) flags);
writeLabel(bytes, arc.label);
// System.out.println(" write arc: label=" + (char) arc.label + " flags=" + flags + " target=" + target.node + " pos=" + bytes.getPosition() + " output=" + outputs.outputToString(arc.output));
if (arc.output != NO_OUTPUT) {
outputs.write(arc.output, bytes);
//System.out.println(" write output");
arcWithOutputCount++;
}
if (arc.nextFinalOutput != NO_OUTPUT) {
//System.out.println(" write final output");
outputs.writeFinalOutput(arc.nextFinalOutput, bytes);
}
if (targetHasArcs && (flags & BIT_TARGET_NEXT) == 0) {
assert target.node > 0;
//System.out.println(" write target");
bytes.writeVLong(target.node);
}
// just write the arcs "like normal" on first pass,
// but record how many bytes each one took, and max
// byte size:
if (doFixedArray) {
bytesPerArc[arcIdx] = (int) (bytes.getPosition() - lastArcStart);
lastArcStart = bytes.getPosition();
maxBytesPerArc = Math.max(maxBytesPerArc, bytesPerArc[arcIdx]);
//System.out.println(" bytes=" + bytesPerArc[arcIdx]);
}
}
// TODO: try to avoid wasteful cases: disable doFixedArray in that case
/*
*
* LUCENE-4682: what is a fair heuristic here?
* It could involve some of these:
* 1. how "busy" the node is: nodeIn.inputCount relative to frontier[0].inputCount?
* 2. how much binSearch saves over scan: nodeIn.numArcs
* 3. waste: numBytes vs numBytesExpanded
*
* the one below just looks at #3
if (doFixedArray) {
// rough heuristic: make this 1.25 "waste factor" a parameter to the phd ctor????
int numBytes = lastArcStart - startAddress;
int numBytesExpanded = maxBytesPerArc * nodeIn.numArcs;
if (numBytesExpanded > numBytes*1.25) {
doFixedArray = false;
}
}
*/
if (doFixedArray) {
final int MAX_HEADER_SIZE = 11; // header(byte) + numArcs(vint) + numBytes(vint)
assert maxBytesPerArc > 0;
// 2nd pass just "expands" all arcs to take up a fixed
// byte size
//System.out.println("write int @pos=" + (fixedArrayStart-4) + " numArcs=" + nodeIn.numArcs);
// create the header
// TODO: clean this up: or just rewind+reuse and deal with it
byte header[] = new byte[MAX_HEADER_SIZE];
ByteArrayDataOutput bad = new ByteArrayDataOutput(header);
// write a "false" first arc:
bad.writeByte(ARCS_AS_FIXED_ARRAY);
bad.writeVInt(nodeIn.numArcs);
bad.writeVInt(maxBytesPerArc);
int headerLen = bad.getPosition();
final long fixedArrayStart = startAddress + headerLen;
// expand the arcs in place, backwards
long srcPos = bytes.getPosition();
long destPos = fixedArrayStart + nodeIn.numArcs*maxBytesPerArc;
assert destPos >= srcPos;
if (destPos > srcPos) {
bytes.skipBytes((int) (destPos - srcPos));
for(int arcIdx=nodeIn.numArcs-1;arcIdx>=0;arcIdx--) {
destPos -= maxBytesPerArc;
srcPos -= bytesPerArc[arcIdx];
//System.out.println(" repack arcIdx=" + arcIdx + " srcPos=" + srcPos + " destPos=" + destPos);
if (srcPos != destPos) {
//System.out.println(" copy len=" + bytesPerArc[arcIdx]);
assert destPos > srcPos: "destPos=" + destPos + " srcPos=" + srcPos + " arcIdx=" + arcIdx + " maxBytesPerArc=" + maxBytesPerArc + " bytesPerArc[arcIdx]=" + bytesPerArc[arcIdx] + " nodeIn.numArcs=" + nodeIn.numArcs;
bytes.copyBytes(srcPos, destPos, bytesPerArc[arcIdx]);
}
}
}
// now write the header
bytes.writeBytes(startAddress, header, 0, headerLen);
}
final long thisNodeAddress = bytes.getPosition()-1;
bytes.reverse(startAddress, thisNodeAddress);
// PackedInts uses int as the index, so we cannot handle
// > 2.1B nodes when packing:
if (nodeAddress != null && nodeCount == Integer.MAX_VALUE) {
throw new IllegalStateException("cannot create a packed FST with more than 2.1 billion nodes");
}
nodeCount++;
final long node;
if (nodeAddress != null) {
// Nodes are addressed by 1+ord:
if ((int) nodeCount == nodeAddress.size()) {
nodeAddress = nodeAddress.resize(ArrayUtil.oversize(nodeAddress.size() + 1, nodeAddress.getBitsPerValue()));
inCounts = inCounts.resize(ArrayUtil.oversize(inCounts.size() + 1, inCounts.getBitsPerValue()));
}
nodeAddress.set((int) nodeCount, thisNodeAddress);
// System.out.println(" write nodeAddress[" + nodeCount + "] = " + endAddress);
node = nodeCount;
} else {
node = thisNodeAddress;
}
lastFrozenNode = node;
//System.out.println(" ret node=" + node + " address=" + thisNodeAddress + " nodeAddress=" + nodeAddress);
return node;
}
/** Fills virtual 'start' arc, ie, an empty incoming arc to
* the FST's start node */
public Arc<T> getFirstArc(Arc<T> arc) {
if (emptyOutput != null) {
arc.flags = BIT_FINAL_ARC | BIT_LAST_ARC;
arc.nextFinalOutput = emptyOutput;
} else {
arc.flags = BIT_LAST_ARC;
arc.nextFinalOutput = NO_OUTPUT;
}
arc.output = NO_OUTPUT;
// If there are no nodes, ie, the FST only accepts the
// empty string, then startNode is 0
arc.target = startNode;
return arc;
}
/** Follows the <code>follow</code> arc and reads the last
* arc of its target; this changes the provided
* <code>arc</code> (2nd arg) in-place and returns it.
*
* @return Returns the second argument
* (<code>arc</code>). */
public Arc<T> readLastTargetArc(Arc<T> follow, Arc<T> arc, BytesReader in) throws IOException {
//System.out.println("readLast");
if (!targetHasArcs(follow)) {
//System.out.println(" end node");
assert follow.isFinal();
arc.label = END_LABEL;
arc.target = FINAL_END_NODE;
arc.output = follow.nextFinalOutput;
arc.flags = BIT_LAST_ARC;
return arc;
} else {
in.setPosition(getNodeAddress(follow.target));
arc.node = follow.target;
final byte b = in.readByte();
if (b == ARCS_AS_FIXED_ARRAY) {
// array: jump straight to end
arc.numArcs = in.readVInt();
if (packed || version >= VERSION_VINT_TARGET) {
arc.bytesPerArc = in.readVInt();
} else {
arc.bytesPerArc = in.readInt();
}
//System.out.println(" array numArcs=" + arc.numArcs + " bpa=" + arc.bytesPerArc);
arc.posArcsStart = in.getPosition();
arc.arcIdx = arc.numArcs - 2;
} else {
arc.flags = b;
// non-array: linear scan
arc.bytesPerArc = 0;
//System.out.println(" scan");
while(!arc.isLast()) {
// skip this arc:
readLabel(in);
if (arc.flag(BIT_ARC_HAS_OUTPUT)) {
outputs.read(in);
}
if (arc.flag(BIT_ARC_HAS_FINAL_OUTPUT)) {
outputs.readFinalOutput(in);
}
if (arc.flag(BIT_STOP_NODE)) {
} else if (arc.flag(BIT_TARGET_NEXT)) {
} else if (packed) {
in.readVLong();
} else {
readUnpackedNodeTarget(in);
}
arc.flags = in.readByte();
}
// Undo the byte flags we read:
in.skipBytes(-1);
arc.nextArc = in.getPosition();
}
readNextRealArc(arc, in);
assert arc.isLast();
return arc;
}
}
private long readUnpackedNodeTarget(BytesReader in) throws IOException {
long target;
if (version < VERSION_VINT_TARGET) {
target = in.readInt();
} else {
target = in.readVLong();
}
return target;
}
/**
* Follow the <code>follow</code> arc and read the first arc of its target;
* this changes the provided <code>arc</code> (2nd arg) in-place and returns
* it.
*
* @return Returns the second argument (<code>arc</code>).
*/
public Arc<T> readFirstTargetArc(Arc<T> follow, Arc<T> arc, BytesReader in) throws IOException {
//int pos = address;
//System.out.println(" readFirstTarget follow.target=" + follow.target + " isFinal=" + follow.isFinal());
if (follow.isFinal()) {
// Insert "fake" final first arc:
arc.label = END_LABEL;
arc.output = follow.nextFinalOutput;
arc.flags = BIT_FINAL_ARC;
if (follow.target <= 0) {
arc.flags |= BIT_LAST_ARC;
} else {
arc.node = follow.target;
// NOTE: nextArc is a node (not an address!) in this case:
arc.nextArc = follow.target;
}
arc.target = FINAL_END_NODE;
//System.out.println(" insert isFinal; nextArc=" + follow.target + " isLast=" + arc.isLast() + " output=" + outputs.outputToString(arc.output));
return arc;
} else {
return readFirstRealTargetArc(follow.target, arc, in);
}
}
public Arc<T> readFirstRealTargetArc(long node, Arc<T> arc, final BytesReader in) throws IOException {
final long address = getNodeAddress(node);
in.setPosition(address);
//System.out.println(" readFirstRealTargtArc address="
//+ address);
//System.out.println(" flags=" + arc.flags);
arc.node = node;
if (in.readByte() == ARCS_AS_FIXED_ARRAY) {
//System.out.println(" fixedArray");
// this is first arc in a fixed-array
arc.numArcs = in.readVInt();
if (packed || version >= VERSION_VINT_TARGET) {
arc.bytesPerArc = in.readVInt();
} else {
arc.bytesPerArc = in.readInt();
}
arc.arcIdx = -1;
arc.nextArc = arc.posArcsStart = in.getPosition();
//System.out.println(" bytesPer=" + arc.bytesPerArc + " numArcs=" + arc.numArcs + " arcsStart=" + pos);
} else {
//arc.flags = b;
arc.nextArc = address;
arc.bytesPerArc = 0;
}
return readNextRealArc(arc, in);
}
/**
* Checks if <code>arc</code>'s target state is in expanded (or vector) format.
*
* @return Returns <code>true</code> if <code>arc</code> points to a state in an
* expanded array format.
*/
boolean isExpandedTarget(Arc<T> follow, BytesReader in) throws IOException {
if (!targetHasArcs(follow)) {
return false;
} else {
in.setPosition(getNodeAddress(follow.target));
return in.readByte() == ARCS_AS_FIXED_ARRAY;
}
}
/** In-place read; returns the arc. */
public Arc<T> readNextArc(Arc<T> arc, BytesReader in) throws IOException {
if (arc.label == END_LABEL) {
// This was a fake inserted "final" arc
if (arc.nextArc <= 0) {
throw new IllegalArgumentException("cannot readNextArc when arc.isLast()=true");
}
return readFirstRealTargetArc(arc.nextArc, arc, in);
} else {
return readNextRealArc(arc, in);
}
}
/** Peeks at next arc's label; does not alter arc. Do
* not call this if arc.isLast()! */
public int readNextArcLabel(Arc<T> arc, BytesReader in) throws IOException {
assert !arc.isLast();
if (arc.label == END_LABEL) {
//System.out.println(" nextArc fake " +
//arc.nextArc);
long pos = getNodeAddress(arc.nextArc);
in.setPosition(pos);
final byte b = in.readByte();
if (b == ARCS_AS_FIXED_ARRAY) {
//System.out.println(" nextArc fixed array");
in.readVInt();
// Skip bytesPerArc:
if (packed || version >= VERSION_VINT_TARGET) {
in.readVInt();
} else {
in.readInt();
}
} else {
in.setPosition(pos);
}
} else {
if (arc.bytesPerArc != 0) {
//System.out.println(" nextArc real array");
// arcs are at fixed entries
in.setPosition(arc.posArcsStart);
in.skipBytes((1+arc.arcIdx)*arc.bytesPerArc);
} else {
// arcs are packed
//System.out.println(" nextArc real packed");
in.setPosition(arc.nextArc);
}
}
// skip flags
in.readByte();
return readLabel(in);
}
/** Never returns null, but you should never call this if
* arc.isLast() is true. */
public Arc<T> readNextRealArc(Arc<T> arc, final BytesReader in) throws IOException {
// TODO: can't assert this because we call from readFirstArc
// assert !flag(arc.flags, BIT_LAST_ARC);
// this is a continuing arc in a fixed array
if (arc.bytesPerArc != 0) {
// arcs are at fixed entries
arc.arcIdx++;
assert arc.arcIdx < arc.numArcs;
in.setPosition(arc.posArcsStart);
in.skipBytes(arc.arcIdx*arc.bytesPerArc);
} else {
// arcs are packed
in.setPosition(arc.nextArc);
}
arc.flags = in.readByte();
arc.label = readLabel(in);
if (arc.flag(BIT_ARC_HAS_OUTPUT)) {
arc.output = outputs.read(in);
} else {
arc.output = outputs.getNoOutput();
}
if (arc.flag(BIT_ARC_HAS_FINAL_OUTPUT)) {
arc.nextFinalOutput = outputs.readFinalOutput(in);
} else {
arc.nextFinalOutput = outputs.getNoOutput();
}
if (arc.flag(BIT_STOP_NODE)) {
if (arc.flag(BIT_FINAL_ARC)) {
arc.target = FINAL_END_NODE;
} else {
arc.target = NON_FINAL_END_NODE;
}
arc.nextArc = in.getPosition();
} else if (arc.flag(BIT_TARGET_NEXT)) {
arc.nextArc = in.getPosition();
// TODO: would be nice to make this lazy -- maybe
// caller doesn't need the target and is scanning arcs...
if (nodeAddress == null) {
if (!arc.flag(BIT_LAST_ARC)) {
if (arc.bytesPerArc == 0) {
// must scan
seekToNextNode(in);
} else {
in.setPosition(arc.posArcsStart);
in.skipBytes(arc.bytesPerArc * arc.numArcs);
}
}
arc.target = in.getPosition();
} else {
arc.target = arc.node - 1;
assert arc.target > 0;
}
} else {
if (packed) {
final long pos = in.getPosition();
final long code = in.readVLong();
if (arc.flag(BIT_TARGET_DELTA)) {
// Address is delta-coded from current address:
arc.target = pos + code;
//System.out.println(" delta pos=" + pos + " delta=" + code + " target=" + arc.target);
} else if (code < nodeRefToAddress.size()) {
// Deref
arc.target = nodeRefToAddress.get((int) code);
//System.out.println(" deref code=" + code + " target=" + arc.target);
} else {
// Absolute
arc.target = code;
//System.out.println(" abs code=" + code);
}
} else {
arc.target = readUnpackedNodeTarget(in);
}
arc.nextArc = in.getPosition();
}
return arc;
}
// TODO: could we somehow [partially] tableize arc lookups
// look automaton?
/** Finds an arc leaving the incoming arc, replacing the arc in place.
* This returns null if the arc was not found, else the incoming arc. */
public Arc<T> findTargetArc(int labelToMatch, Arc<T> follow, Arc<T> arc, BytesReader in) throws IOException {
if (labelToMatch == END_LABEL) {
if (follow.isFinal()) {
if (follow.target <= 0) {
arc.flags = BIT_LAST_ARC;
} else {
arc.flags = 0;
// NOTE: nextArc is a node (not an address!) in this case:
arc.nextArc = follow.target;
arc.node = follow.target;
}
arc.output = follow.nextFinalOutput;
arc.label = END_LABEL;
return arc;
} else {
return null;
}
}
// Short-circuit if this arc is in the root arc cache:
if (follow.target == startNode && labelToMatch < cachedRootArcs.length) {
// LUCENE-5152: detect tricky cases where caller
// modified previously returned cached root-arcs:
assert assertRootArcs();
final Arc<T> result = cachedRootArcs[labelToMatch];
if (result == null) {
return null;
} else {
arc.copyFrom(result);
return arc;
}
}
if (!targetHasArcs(follow)) {
return null;
}
in.setPosition(getNodeAddress(follow.target));
arc.node = follow.target;
// System.out.println("fta label=" + (char) labelToMatch);
if (in.readByte() == ARCS_AS_FIXED_ARRAY) {
// Arcs are full array; do binary search:
arc.numArcs = in.readVInt();
if (packed || version >= VERSION_VINT_TARGET) {
arc.bytesPerArc = in.readVInt();
} else {
arc.bytesPerArc = in.readInt();
}
arc.posArcsStart = in.getPosition();
int low = 0;
int high = arc.numArcs-1;
while (low <= high) {
//System.out.println(" cycle");
int mid = (low + high) >>> 1;
in.setPosition(arc.posArcsStart);
in.skipBytes(arc.bytesPerArc*mid + 1);
int midLabel = readLabel(in);
final int cmp = midLabel - labelToMatch;
if (cmp < 0) {
low = mid + 1;
} else if (cmp > 0) {
high = mid - 1;
} else {
arc.arcIdx = mid-1;
//System.out.println(" found!");
return readNextRealArc(arc, in);
}
}
return null;
}
// Linear scan
readFirstRealTargetArc(follow.target, arc, in);
while(true) {
//System.out.println(" non-bs cycle");
// TODO: we should fix this code to not have to create
// object for the output of every arc we scan... only
// for the matching arc, if found
if (arc.label == labelToMatch) {
//System.out.println(" found!");
return arc;
} else if (arc.label > labelToMatch) {
return null;
} else if (arc.isLast()) {
return null;
} else {
readNextRealArc(arc, in);
}
}
}
private void seekToNextNode(BytesReader in) throws IOException {
while(true) {
final int flags = in.readByte();
readLabel(in);
if (flag(flags, BIT_ARC_HAS_OUTPUT)) {
outputs.read(in);
}
if (flag(flags, BIT_ARC_HAS_FINAL_OUTPUT)) {
outputs.readFinalOutput(in);
}
if (!flag(flags, BIT_STOP_NODE) && !flag(flags, BIT_TARGET_NEXT)) {
if (packed) {
in.readVLong();
} else {
readUnpackedNodeTarget(in);
}
}
if (flag(flags, BIT_LAST_ARC)) {
return;
}
}
}
public long getNodeCount() {
// 1+ in order to count the -1 implicit final node
return 1+nodeCount;
}
public long getArcCount() {
return arcCount;
}
public long getArcWithOutputCount() {
return arcWithOutputCount;
}
/**
* Nodes will be expanded if their depth (distance from the root node) is
* <= this value and their number of arcs is >=
* {@link #FIXED_ARRAY_NUM_ARCS_SHALLOW}.
*
* <p>
* Fixed array consumes more RAM but enables binary search on the arcs
* (instead of a linear scan) on lookup by arc label.
*
* @return <code>true</code> if <code>node</code> should be stored in an
* expanded (array) form.
*
* @see #FIXED_ARRAY_NUM_ARCS_DEEP
* @see Builder.UnCompiledNode#depth
*/
private boolean shouldExpand(UnCompiledNode<T> node) {
return allowArrayArcs &&
((node.depth <= FIXED_ARRAY_SHALLOW_DISTANCE && node.numArcs >= FIXED_ARRAY_NUM_ARCS_SHALLOW) ||
node.numArcs >= FIXED_ARRAY_NUM_ARCS_DEEP);
}
/** Returns a {@link BytesReader} for this FST, positioned at
* position 0. */
public BytesReader getBytesReader() {
BytesReader in;
if (packed) {
in = bytes.getForwardReader();
} else {
in = bytes.getReverseReader();
}
return in;
}
/** Reads bytes stored in an FST. */
public static abstract class BytesReader extends DataInput {
/** Get current read position. */
public abstract long getPosition();
/** Set current read position. */
public abstract void setPosition(long pos);
/** Returns true if this reader uses reversed bytes
* under-the-hood. */
public abstract boolean reversed();
/** Skips bytes. */
public abstract void skipBytes(int count);
}
private static class ArcAndState<T> {
final Arc<T> arc;
final IntsRef chain;
public ArcAndState(Arc<T> arc, IntsRef chain) {
this.arc = arc;
this.chain = chain;
}
}
/*
public void countSingleChains() throws IOException {
// TODO: must assert this FST was built with
// "willRewrite"
final List<ArcAndState<T>> queue = new ArrayList<ArcAndState<T>>();
// TODO: use bitset to not revisit nodes already
// visited
FixedBitSet seen = new FixedBitSet(1+nodeCount);
int saved = 0;
queue.add(new ArcAndState<T>(getFirstArc(new Arc<T>()), new IntsRef()));
Arc<T> scratchArc = new Arc<T>();
while(queue.size() > 0) {
//System.out.println("cycle size=" + queue.size());
//for(ArcAndState<T> ent : queue) {
// System.out.println(" " + Util.toBytesRef(ent.chain, new BytesRef()));
// }
final ArcAndState<T> arcAndState = queue.get(queue.size()-1);
seen.set(arcAndState.arc.node);
final BytesRef br = Util.toBytesRef(arcAndState.chain, new BytesRef());
if (br.length > 0 && br.bytes[br.length-1] == -1) {
br.length--;
}
//System.out.println(" top node=" + arcAndState.arc.target + " chain=" + br.utf8ToString());
if (targetHasArcs(arcAndState.arc) && !seen.get(arcAndState.arc.target)) {
// push
readFirstTargetArc(arcAndState.arc, scratchArc);
//System.out.println(" push label=" + (char) scratchArc.label);
//System.out.println(" tonode=" + scratchArc.target + " last?=" + scratchArc.isLast());
final IntsRef chain = IntsRef.deepCopyOf(arcAndState.chain);
chain.grow(1+chain.length);
// TODO
//assert scratchArc.label != END_LABEL;
chain.ints[chain.length] = scratchArc.label;
chain.length++;
if (scratchArc.isLast()) {
if (scratchArc.target != -1 && inCounts[scratchArc.target] == 1) {
//System.out.println(" append");
} else {
if (arcAndState.chain.length > 1) {
saved += chain.length-2;
try {
System.out.println("chain: " + Util.toBytesRef(chain, new BytesRef()).utf8ToString());
} catch (AssertionError ae) {
System.out.println("chain: " + Util.toBytesRef(chain, new BytesRef()));
}
}
chain.length = 0;
}
} else {
//System.out.println(" reset");
if (arcAndState.chain.length > 1) {
saved += arcAndState.chain.length-2;
try {
System.out.println("chain: " + Util.toBytesRef(arcAndState.chain, new BytesRef()).utf8ToString());
} catch (AssertionError ae) {
System.out.println("chain: " + Util.toBytesRef(arcAndState.chain, new BytesRef()));
}
}
if (scratchArc.target != -1 && inCounts[scratchArc.target] != 1) {
chain.length = 0;
} else {
chain.ints[0] = scratchArc.label;
chain.length = 1;
}
}
// TODO: instead of new Arc() we can re-use from
// a by-depth array
queue.add(new ArcAndState<T>(new Arc<T>().copyFrom(scratchArc), chain));
} else if (!arcAndState.arc.isLast()) {
// next
readNextArc(arcAndState.arc);
//System.out.println(" next label=" + (char) arcAndState.arc.label + " len=" + arcAndState.chain.length);
if (arcAndState.chain.length != 0) {
arcAndState.chain.ints[arcAndState.chain.length-1] = arcAndState.arc.label;
}
} else {
if (arcAndState.chain.length > 1) {
saved += arcAndState.chain.length-2;
System.out.println("chain: " + Util.toBytesRef(arcAndState.chain, new BytesRef()).utf8ToString());
}
// pop
//System.out.println(" pop");
queue.remove(queue.size()-1);
while(queue.size() > 0 && queue.get(queue.size()-1).arc.isLast()) {
queue.remove(queue.size()-1);
}
if (queue.size() > 0) {
final ArcAndState<T> arcAndState2 = queue.get(queue.size()-1);
readNextArc(arcAndState2.arc);
//System.out.println(" read next=" + (char) arcAndState2.arc.label + " queue=" + queue.size());
assert arcAndState2.arc.label != END_LABEL;
if (arcAndState2.chain.length != 0) {
arcAndState2.chain.ints[arcAndState2.chain.length-1] = arcAndState2.arc.label;
}
}
}
}
System.out.println("TOT saved " + saved);
}
*/
// Creates a packed FST
private FST(INPUT_TYPE inputType, Outputs<T> outputs, int bytesPageBits) {
version = VERSION_CURRENT;
packed = true;
this.inputType = inputType;
bytes = new BytesStore(bytesPageBits);
this.outputs = outputs;
NO_OUTPUT = outputs.getNoOutput();
// NOTE: bogus because this is only used during
// building; we need to break out mutable FST from
// immutable
allowArrayArcs = false;
}
/** Expert: creates an FST by packing this one. This
* process requires substantial additional RAM (currently
* up to ~8 bytes per node depending on
* <code>acceptableOverheadRatio</code>), but then should
* produce a smaller FST.
*
* <p>The implementation of this method uses ideas from
* <a target="_blank" href="http://www.cs.put.poznan.pl/dweiss/site/publications/download/fsacomp.pdf">Smaller Representation of Finite State Automata</a>,
* which describes techniques to reduce the size of a FST.
* However, this is not a strict implementation of the
* algorithms described in this paper.
*/
FST<T> pack(int minInCountDeref, int maxDerefNodes, float acceptableOverheadRatio) throws IOException {
// NOTE: maxDerefNodes is intentionally int: we cannot
// support > 2.1B deref nodes
// TODO: other things to try
// - renumber the nodes to get more next / better locality?
// - allow multiple input labels on an arc, so
// singular chain of inputs can take one arc (on
// wikipedia terms this could save another ~6%)
// - in the ord case, the output '1' is presumably
// very common (after NO_OUTPUT)... maybe use a bit
// for it..?
// - use spare bits in flags.... for top few labels /
// outputs / targets
if (nodeAddress == null) {
throw new IllegalArgumentException("this FST was not built with willPackFST=true");
}
Arc<T> arc = new Arc<T>();
final BytesReader r = getBytesReader();
final int topN = Math.min(maxDerefNodes, inCounts.size());
// Find top nodes with highest number of incoming arcs:
NodeQueue q = new NodeQueue(topN);
// TODO: we could use more RAM efficient selection algo here...
NodeAndInCount bottom = null;
for(int node=0; node<inCounts.size(); node++) {
if (inCounts.get(node) >= minInCountDeref) {
if (bottom == null) {
q.add(new NodeAndInCount(node, (int) inCounts.get(node)));
if (q.size() == topN) {
bottom = q.top();
}
} else if (inCounts.get(node) > bottom.count) {
q.insertWithOverflow(new NodeAndInCount(node, (int) inCounts.get(node)));
}
}
}
// Free up RAM:
inCounts = null;
final Map<Integer,Integer> topNodeMap = new HashMap<Integer,Integer>();
for(int downTo=q.size()-1;downTo>=0;downTo--) {
NodeAndInCount n = q.pop();
topNodeMap.put(n.node, downTo);
//System.out.println("map node=" + n.node + " inCount=" + n.count + " to newID=" + downTo);
}
// +1 because node ords start at 1 (0 is reserved as stop node):
final GrowableWriter newNodeAddress = new GrowableWriter(
PackedInts.bitsRequired(this.bytes.getPosition()), (int) (1 + nodeCount), acceptableOverheadRatio);
// Fill initial coarse guess:
for(int node=1;node<=nodeCount;node++) {
newNodeAddress.set(node, 1 + this.bytes.getPosition() - nodeAddress.get(node));
}
int absCount;
int deltaCount;
int topCount;
int nextCount;
FST<T> fst;
// Iterate until we converge:
while(true) {
//System.out.println("\nITER");
boolean changed = false;
// for assert:
boolean negDelta = false;
fst = new FST<T>(inputType, outputs, bytes.getBlockBits());
final BytesStore writer = fst.bytes;
// Skip 0 byte since 0 is reserved target:
writer.writeByte((byte) 0);
fst.arcWithOutputCount = 0;
fst.nodeCount = 0;
fst.arcCount = 0;
absCount = deltaCount = topCount = nextCount = 0;
int changedCount = 0;
long addressError = 0;
//int totWasted = 0;
// Since we re-reverse the bytes, we now write the
// nodes backwards, so that BIT_TARGET_NEXT is
// unchanged:
for(int node=(int)nodeCount;node>=1;node--) {
fst.nodeCount++;
final long address = writer.getPosition();
//System.out.println(" node: " + node + " address=" + address);
if (address != newNodeAddress.get(node)) {
addressError = address - newNodeAddress.get(node);
//System.out.println(" change: " + (address - newNodeAddress[node]));
changed = true;
newNodeAddress.set(node, address);
changedCount++;
}
int nodeArcCount = 0;
int bytesPerArc = 0;
boolean retry = false;
// for assert:
boolean anyNegDelta = false;
// Retry loop: possibly iterate more than once, if
// this is an array'd node and bytesPerArc changes:
writeNode:
while(true) { // retry writing this node
//System.out.println(" cycle: retry");
readFirstRealTargetArc(node, arc, r);
final boolean useArcArray = arc.bytesPerArc != 0;
if (useArcArray) {
// Write false first arc:
if (bytesPerArc == 0) {
bytesPerArc = arc.bytesPerArc;
}
writer.writeByte(ARCS_AS_FIXED_ARRAY);
writer.writeVInt(arc.numArcs);
writer.writeVInt(bytesPerArc);
//System.out.println("node " + node + ": " + arc.numArcs + " arcs");
}
int maxBytesPerArc = 0;
//int wasted = 0;
while(true) { // iterate over all arcs for this node
//System.out.println(" cycle next arc");
final long arcStartPos = writer.getPosition();
nodeArcCount++;
byte flags = 0;
if (arc.isLast()) {
flags += BIT_LAST_ARC;
}
/*
if (!useArcArray && nodeUpto < nodes.length-1 && arc.target == nodes[nodeUpto+1]) {
flags += BIT_TARGET_NEXT;
}
*/
if (!useArcArray && node != 1 && arc.target == node-1) {
flags += BIT_TARGET_NEXT;
if (!retry) {
nextCount++;
}
}
if (arc.isFinal()) {
flags += BIT_FINAL_ARC;
if (arc.nextFinalOutput != NO_OUTPUT) {
flags += BIT_ARC_HAS_FINAL_OUTPUT;
}
} else {
assert arc.nextFinalOutput == NO_OUTPUT;
}
if (!targetHasArcs(arc)) {
flags += BIT_STOP_NODE;
}
if (arc.output != NO_OUTPUT) {
flags += BIT_ARC_HAS_OUTPUT;
}
final long absPtr;
final boolean doWriteTarget = targetHasArcs(arc) && (flags & BIT_TARGET_NEXT) == 0;
if (doWriteTarget) {
final Integer ptr = topNodeMap.get(arc.target);
if (ptr != null) {
absPtr = ptr;
} else {
absPtr = topNodeMap.size() + newNodeAddress.get((int) arc.target) + addressError;
}
long delta = newNodeAddress.get((int) arc.target) + addressError - writer.getPosition() - 2;
if (delta < 0) {
//System.out.println("neg: " + delta);
anyNegDelta = true;
delta = 0;
}
if (delta < absPtr) {
flags |= BIT_TARGET_DELTA;
}
} else {
absPtr = 0;
}
assert flags != ARCS_AS_FIXED_ARRAY;
writer.writeByte(flags);
fst.writeLabel(writer, arc.label);
if (arc.output != NO_OUTPUT) {
outputs.write(arc.output, writer);
if (!retry) {
fst.arcWithOutputCount++;
}
}
if (arc.nextFinalOutput != NO_OUTPUT) {
outputs.writeFinalOutput(arc.nextFinalOutput, writer);
}
if (doWriteTarget) {
long delta = newNodeAddress.get((int) arc.target) + addressError - writer.getPosition();
if (delta < 0) {
anyNegDelta = true;
//System.out.println("neg: " + delta);
delta = 0;
}
if (flag(flags, BIT_TARGET_DELTA)) {
//System.out.println(" delta");
writer.writeVLong(delta);
if (!retry) {
deltaCount++;
}
} else {
/*
if (ptr != null) {
System.out.println(" deref");
} else {
System.out.println(" abs");
}
*/
writer.writeVLong(absPtr);
if (!retry) {
if (absPtr >= topNodeMap.size()) {
absCount++;
} else {
topCount++;
}
}
}
}
if (useArcArray) {
final int arcBytes = (int) (writer.getPosition() - arcStartPos);
//System.out.println(" " + arcBytes + " bytes");
maxBytesPerArc = Math.max(maxBytesPerArc, arcBytes);
// NOTE: this may in fact go "backwards", if
// somehow (rarely, possibly never) we use
// more bytesPerArc in this rewrite than the
// incoming FST did... but in this case we
// will retry (below) so it's OK to ovewrite
// bytes:
//wasted += bytesPerArc - arcBytes;
writer.skipBytes((int) (arcStartPos + bytesPerArc - writer.getPosition()));
}
if (arc.isLast()) {
break;
}
readNextRealArc(arc, r);
}
if (useArcArray) {
if (maxBytesPerArc == bytesPerArc || (retry && maxBytesPerArc <= bytesPerArc)) {
// converged
//System.out.println(" bba=" + bytesPerArc + " wasted=" + wasted);
//totWasted += wasted;
break;
}
} else {
break;
}
//System.out.println(" retry this node maxBytesPerArc=" + maxBytesPerArc + " vs " + bytesPerArc);
// Retry:
bytesPerArc = maxBytesPerArc;
writer.truncate(address);
nodeArcCount = 0;
retry = true;
anyNegDelta = false;
}
negDelta |= anyNegDelta;
fst.arcCount += nodeArcCount;
}
if (!changed) {
// We don't renumber the nodes (just reverse their
// order) so nodes should only point forward to
// other nodes because we only produce acyclic FSTs
// w/ nodes only pointing "forwards":
assert !negDelta;
//System.out.println("TOT wasted=" + totWasted);
// Converged!
break;
}
//System.out.println(" " + changedCount + " of " + fst.nodeCount + " changed; retry");
}
long maxAddress = 0;
for (long key : topNodeMap.keySet()) {
maxAddress = Math.max(maxAddress, newNodeAddress.get((int) key));
}
PackedInts.Mutable nodeRefToAddressIn = PackedInts.getMutable(topNodeMap.size(),
PackedInts.bitsRequired(maxAddress), acceptableOverheadRatio);
for(Map.Entry<Integer,Integer> ent : topNodeMap.entrySet()) {
nodeRefToAddressIn.set(ent.getValue(), newNodeAddress.get(ent.getKey()));
}
fst.nodeRefToAddress = nodeRefToAddressIn;
fst.startNode = newNodeAddress.get((int) startNode);
//System.out.println("new startNode=" + fst.startNode + " old startNode=" + startNode);
if (emptyOutput != null) {
fst.setEmptyOutput(emptyOutput);
}
assert fst.nodeCount == nodeCount: "fst.nodeCount=" + fst.nodeCount + " nodeCount=" + nodeCount;
assert fst.arcCount == arcCount;
assert fst.arcWithOutputCount == arcWithOutputCount: "fst.arcWithOutputCount=" + fst.arcWithOutputCount + " arcWithOutputCount=" + arcWithOutputCount;
fst.bytes.finish();
fst.cacheRootArcs();
//final int size = fst.sizeInBytes();
//System.out.println("nextCount=" + nextCount + " topCount=" + topCount + " deltaCount=" + deltaCount + " absCount=" + absCount);
return fst;
}
private static class NodeAndInCount implements Comparable<NodeAndInCount> {
final int node;
final int count;
public NodeAndInCount(int node, int count) {
this.node = node;
this.count = count;
}
@Override
public int compareTo(NodeAndInCount other) {
if (count > other.count) {
return 1;
} else if (count < other.count) {
return -1;
} else {
// Tie-break: smaller node compares as greater than
return other.node - node;
}
}
}
private static class NodeQueue extends PriorityQueue<NodeAndInCount> {
public NodeQueue(int topN) {
super(topN, false);
}
@Override
public boolean lessThan(NodeAndInCount a, NodeAndInCount b) {
final int cmp = a.compareTo(b);
assert cmp != 0;
return cmp < 0;
}
}
}