import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
@Override
protected void write(OutputBitStream obs, int[] in, int offset, int len) throws IOException {
    int l = 31 - Integer.numberOfLeadingZeros(in[offset + len - 1] / len);
    int mask = (1 << l) - 1;

    if (l < 1) {
        l = 1;
        mask = 1;
    }

    int d = 0;
    obs.writeInt(l, 32);
    for (int i = offset; i < offset + len; i++) {
        final int x = in[i];
        final int hx = x >> l;
        obs.writeUnary(hx - d);
        obs.writeInt(x & mask, l);
        d = hx;
    }
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
@Override
protected void write(OutputBitStream obs, int[] in, int offset, int len) throws IOException {
    long sum = 0;
    for (int i = offset; i < offset + len; i++) {
        sum += in[i];
    }
    int b = (int) (0.69 * sum / (double) len);
    if (b == 0) {
        b = 1;
    }
    int log2b = 31 - Integer.numberOfLeadingZeros(b);

    obs.writeInt(log2b, 32);
    for (int i = offset; i < offset + len; i++) {
        obs.writeUnary(in[i] >> log2b);
        obs.writeInt(in[i] & ((1 << log2b) - 1), log2b);
    }
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
@Override
public byte[] co(int[] in, int offset, int len) {

    byte[] out = new byte[len * 4 + 1024];
    int writtenBits = 0;
    try (OutputBitStream obs = new OutputBitStream(out)) {
        write(obs, in, offset, len);
        writtenBits = (int) obs.writtenBits();
    } catch (IOException ex) {
        LOG.log(Level.SEVERE, null, ex);
    }

    out = Arrays.copyOf(out, (writtenBits + 7) / 8);

    add(len * Integer.BYTES, out.length * Byte.BYTES);

    return out;
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
/** Write the offset file to a given bit stream.
 * @param obs the output bit stream to which offsets will be written.
 * @param pl a progress logger, or <code>null</code>.  
 */
public void writeOffsets( final OutputBitStream obs, final ProgressLogger pl ) throws IOException {
	final BVGraphNodeIterator nodeIterator = (BVGraphNodeIterator) nodeIterator( 0 );
	int n = numNodes();
	long lastOffset = 0;
	while( n-- != 0 ) {
			// We fetch the current position of the underlying input bit stream, which is at the start of the next node.
			writeOffset( obs, nodeIterator.ibs.readBits() - lastOffset );
			lastOffset = nodeIterator.ibs.readBits();
			nodeIterator.nextInt();
			nodeIterator.outdegree();
			nodeIterator.successorArray();
			if ( pl != null ) pl.update();
	}
	writeOffset( obs, nodeIterator.ibs.readBits() - lastOffset );
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
public String createGraphWithFixedWidthLabels( File basename, ImmutableGraph g, int width ) throws IllegalArgumentException, SecurityException, IOException {
	final int n = g.numNodes();
	System.err.println( "Testing " + n + " nodes, width " + width+ ", basename " + basename );

	OutputBitStream labels = createTempBitStream( basename + "-fixedlabel" + BitStreamArcLabelledImmutableGraph.LABELS_EXTENSION );
	OutputBitStream offsets = createTempBitStream( basename + "-fixedlabel" + BitStreamArcLabelledImmutableGraph.LABEL_OFFSETS_EXTENSION );
	offsets.writeGamma( 0 );
	for( int i = 0; i < n; i++ ) {
		int bits = 0;
		for( IntIterator j = LazyIntIterators.eager( g.successors( i ) ); j.hasNext(); ) bits += labels.writeInt( i * j.nextInt() + i, width );
		offsets.writeGamma( bits );
	}
	labels.close();
	offsets.close();

	PrintWriter pw = new PrintWriter( new FileWriter( basename + "-fixedlabel.properties" ) );
	pw.println( ImmutableGraph.GRAPHCLASS_PROPERTY_KEY + " = " + BitStreamArcLabelledImmutableGraph.class.getName() );
	pw.println( BitStreamArcLabelledImmutableGraph.LABELSPEC_PROPERTY_KEY + " = " + FixedWidthIntLabel.class.getName() + "(TEST," + width + ")" );
	pw.println( ArcLabelledImmutableGraph.UNDERLYINGGRAPH_PROPERTY_KEY + " = " + basename.getName() );
	pw.close();
	
	return basename + "-fixedlabel";
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
public String createGraphWithGammaLabels( File basename, ImmutableGraph g ) throws IllegalArgumentException, SecurityException, IOException {
	// We create a complete graph with labels 
	final int n = g.numNodes();
	System.err.println( "Testing " + n + " nodes, gamma coding, basename " + basename );

	OutputBitStream labels = createTempBitStream( basename + "-gammalabel" + BitStreamArcLabelledImmutableGraph.LABELS_EXTENSION );
	OutputBitStream offsets = createTempBitStream( basename + "-gammalabel" + BitStreamArcLabelledImmutableGraph.LABEL_OFFSETS_EXTENSION );
	offsets.writeGamma( 0 );
	for( int i = 0; i < n; i++ ) {
		int bits = 0;
		for( IntIterator j = LazyIntIterators.eager( g.successors( i ) ); j.hasNext(); ) bits += labels.writeGamma( i * j.nextInt() + i );
		offsets.writeGamma( bits );
	}
	labels.close();
	offsets.close();

	PrintWriter pw = new PrintWriter( new FileWriter( basename + "-gammalabel" + ImmutableGraph.PROPERTIES_EXTENSION ) );
	pw.println( ImmutableGraph.GRAPHCLASS_PROPERTY_KEY + " = " + BitStreamArcLabelledImmutableGraph.class.getName() );
	pw.println( BitStreamArcLabelledImmutableGraph.LABELSPEC_PROPERTY_KEY + " = " + GammaCodedIntLabel.class.getName() + "(TEST)" );
	pw.println( ArcLabelledImmutableGraph.UNDERLYINGGRAPH_PROPERTY_KEY + " = " + basename.getName() );
	pw.close();
	
	return basename + "-gammalabel";
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
@Override
public void writeOffsets( final OutputBitStream obs, final ProgressLogger pl ) throws IOException {
    final HdfsBVGraphNodeIterator nodeIterator = (HdfsBVGraphNodeIterator) nodeIterator( 0 );
    int n = numNodes();
    long lastOffset = 0;
    while( n-- != 0 ) {
        writeOffset( obs, nodeIterator.ibs.readBits() - lastOffset );
        lastOffset = nodeIterator.ibs.readBits();
        nodeIterator.nextInt();
        nodeIterator.outdegree();
        nodeIterator.successorArray();
        if ( pl != null ) pl.update();
    }
    writeOffset( obs, nodeIterator.ibs.readBits() - lastOffset );
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
/** Creates a partial compacted trie using given elements, bucket size and transformation strategy.
 *
 * @param elements the elements among which the trie must be able to rank.
 * @param log2BucketSize the logarithm of the size of a bucket.
 * @param transformationStrategy a transformation strategy that must turn the elements in <code>elements</code> into a list of
 * distinct, lexicographically increasing (in iteration order) bit vectors.
 */
@SuppressWarnings("resource")
public PaCoTrieDistributor(final Iterable<? extends T> elements, final int log2BucketSize, final TransformationStrategy<? super T> transformationStrategy) throws IOException {
	this.transformationStrategy = transformationStrategy;
	final ProgressLogger pl = new ProgressLogger(LOGGER);
	pl.displayLocalSpeed = true;
	pl.displayFreeMemory = true;
	pl.itemsName = "keys";
	final PartialTrie<T> immutableBinaryTrie = new PartialTrie<>(elements, log2BucketSize, transformationStrategy, pl);
	final FastByteArrayOutputStream fbStream = new FastByteArrayOutputStream();
	final OutputBitStream trie = new OutputBitStream(fbStream, 0);
	pl.start("Converting to bitstream...");
	numberOfLeaves = immutableBinaryTrie.toStream(trie, pl);
	pl.done();
	defRetValue = -1; // For the very few cases in which we can decide

	LOGGER.info("Trie bit size: " + trie.writtenBits());

	trie.flush();
	fbStream.trim();
	this.trie = fbStream.array;

	if (DDEBUG) {
		final MutableString s = new MutableString();
		recToString(new InputBitStream(this.trie), new MutableString(), s, new MutableString(), 0);
		System.err.println(s);
	}
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
/** Creates a partial compacted trie using given elements, bucket size and transformation strategy.
 *
 * @param elements the elements among which the trie must be able to rank.
 * @param bucketSize the size of a bucket.
 * @param transformationStrategy a transformation strategy that must turn the elements in <code>elements</code> into a list of
 * distinct, lexicographically increasing (in iteration order) bit vectors.
 */
@SuppressWarnings("resource")
public VLPaCoTrieDistributor(final Iterable<? extends T> elements, final long size, final int bucketSize, final TransformationStrategy<? super T> transformationStrategy) throws IOException {
	this.transformationStrategy = transformationStrategy;
	final ProgressLogger pl = new ProgressLogger(LOGGER);
	pl.displayLocalSpeed = true;
	pl.displayFreeMemory = true;
	pl.itemsName = "keys";
	final PartialTrie<T> immutableBinaryTrie = new PartialTrie<>(elements, size, bucketSize, transformationStrategy, pl);
	final FastByteArrayOutputStream fbStream = new FastByteArrayOutputStream();
	final OutputBitStream trie = new OutputBitStream(fbStream, 0);
	pl.expectedUpdates = immutableBinaryTrie.size;
	pl.start("Converting to bitstream...");
	numberOfLeaves = immutableBinaryTrie.toStream(trie, pl);
	pl.done();
	offset = immutableBinaryTrie.offset;

	LOGGER.debug("Trie bit size: " + trie.writtenBits());

	trie.flush();
	fbStream.trim();
	this.trie = fbStream.array;

	if (DDEBUG) {
		final MutableString s = new MutableString();
		recToString(new InputBitStream(this.trie), new MutableString(), s, new MutableString(), 0);
		System.err.println(s);
	}
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
public static void store( final ArcLabelledImmutableGraph graph, final CharSequence basename, final CharSequence underlyingBasename, final ProgressLogger pl ) throws IOException {
	final OutputBitStream labels = new OutputBitStream( basename + LABELS_EXTENSION, STD_BUFFER_SIZE ); 
	final OutputBitStream offsets = new OutputBitStream( basename + LABEL_OFFSETS_EXTENSION, STD_BUFFER_SIZE );

	if ( pl != null ) {
		pl.itemsName = "nodes";
		pl.expectedUpdates = graph.numNodes();
		pl.start( "Saving labels..." );
	}

	final ArcLabelledNodeIterator nodeIterator = graph.nodeIterator();
	offsets.writeGamma( 0 );
	int curr;
	long count;
	LabelledArcIterator successors;

	while( nodeIterator.hasNext() ) {
		curr = nodeIterator.nextInt();
		successors = nodeIterator.successors();
		count = 0;
		while( successors.nextInt() != -1 ) count += successors.label().toBitStream( labels, curr );
		offsets.writeLongGamma( count );
		if ( pl != null ) pl.lightUpdate();
	}
	
	if ( pl != null ) pl.done();
	labels.close();
	offsets.close();
	
	final PrintWriter properties = new PrintWriter( new FileOutputStream( basename + ImmutableGraph.PROPERTIES_EXTENSION ) );
	properties.println( ImmutableGraph.GRAPHCLASS_PROPERTY_KEY + " = " + BitStreamArcLabelledImmutableGraph.class.getName() );
	properties.println( ArcLabelledImmutableGraph.UNDERLYINGGRAPH_PROPERTY_KEY + " = " + underlyingBasename );
	properties.println( BitStreamArcLabelledImmutableGraph.LABELSPEC_PROPERTY_KEY + " = " + graph.prototype().toSpec() );
	properties.close();
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
/** Writes an offset difference to the given stream. 
 *
 * @param obs an offset-file output bit stream.
 * @param x an offset difference to be stored in the stream.
 * @return the number of bits written.
 */
protected final int writeOffset( final OutputBitStream obs, final long x ) throws IOException {
	switch( offsetCoding ) {
	case GAMMA: return obs.writeLongGamma( x ); 
	case DELTA: return obs.writeLongDelta( x ); 
	default: throw new UnsupportedOperationException( "The required offset coding (" + offsetCoding + ") is not supported." );
	}
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
/** Writes an outdegree to the given stream. 
 *
 * @param obs a graph-file output bit stream.
 * @param d an outdegree to be stored in the stream.
 * @return the number of bits written.
 */
protected final int writeOutdegree( final OutputBitStream obs, final int d ) throws IOException {
	switch( outdegreeCoding ) {
	case GAMMA: return obs.writeGamma( d ); 
	case DELTA: return obs.writeDelta( d ); 
	default: throw new UnsupportedOperationException( "The required outdegree coding (" + outdegreeCoding + ") is not supported." );
	}
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
/** Writes a reference to the given stream. 
 *
 * @param obs a graph-file output bit stream.
 * @param ref the reference.
 * @return the number of bits written.
 */
protected final int writeReference( final OutputBitStream obs, final int ref ) throws IOException {

	if ( ref > windowSize ) throw new IllegalStateException( "The required reference (" + ref + ") is incompatible with the window size (" + windowSize + ")" );
	switch( referenceCoding ) {
	case UNARY: return obs.writeUnary( ref );
	case GAMMA: return obs.writeGamma( ref );
	case DELTA: return obs.writeDelta( ref );
	default: throw new UnsupportedOperationException( "The required reference coding (" + referenceCoding + ") is not supported." );
	}
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
/** Writes a block count to the given stream. 
 *
 * @param obs a graph-file output bit stream.
 * @param count the block count.
 * @return the number of written bits.
 */
protected final int writeBlockCount( final OutputBitStream obs, final int count ) throws IOException {
	switch( blockCountCoding ) {
	case UNARY: return obs.writeUnary( count );
	case GAMMA: return obs.writeGamma( count );
	case DELTA: return obs.writeDelta( count );
	default: throw new UnsupportedOperationException( "The required block count coding (" + blockCountCoding + ") is not supported." );
	}
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
/** Writes a block to the given stream. 
 *
 * @param obs a graph-file output bit stream.
 * @param block the block.
 * @return the number of written bits.
 */
protected final int writeBlock( final OutputBitStream obs, final int block ) throws IOException {
	switch( blockCoding ) {
	case UNARY: return obs.writeUnary( block );
	case GAMMA: return obs.writeGamma( block );
	case DELTA: return obs.writeDelta( block );
	default: throw new UnsupportedOperationException( "The required block coding (" + blockCoding + ") is not supported." );
	}
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
/** Writes a residual to the given stream. 
 *
 * @param obs a graph-file output bit stream.
 * @param residual the residual.
 * @return the number of written bits.
 */
protected final int writeResidual( final OutputBitStream obs, final int residual ) throws IOException {
	switch( residualCoding ) {
	case GAMMA: return obs.writeGamma( residual );
	case ZETA: return obs.writeZeta( residual, zetaK );
	case DELTA: return obs.writeDelta( residual );
	case GOLOMB: return obs.writeGolomb( residual, zetaK );
	case NIBBLE: return obs.writeNibble( residual );
	default: throw new UnsupportedOperationException( "The required residuals coding (" + residualCoding + ") is not supported." );
	}
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
public String createGraph( File basename, ImmutableGraph g, int width ) throws IllegalArgumentException, SecurityException, IOException {
	final int n = g.numNodes();
	System.err.println( "Testing " + n + " nodes, width " + width+ ", basename " + basename );

	OutputBitStream labels = new OutputBitStream( basename + "-fixedlabel" + BitStreamArcLabelledImmutableGraph.LABELS_EXTENSION );
	OutputBitStream offsets = new OutputBitStream( basename + "-fixedlabel" + BitStreamArcLabelledImmutableGraph.LABEL_OFFSETS_EXTENSION );
	Label lab;
	offsets.writeGamma( 0 );
	for( int i = 0; i < n; i++ ) {
		int bits = 0;
		for( IntIterator j = LazyIntIterators.eager( g.successors( i ) ); j.hasNext(); ) {
			int succ = j.nextInt();
			lab = new FakeCSFixedWidthIntLabel( "TEST", width, i * succ + i );
			bits += lab.toBitStream( labels, i );
		} 
		offsets.writeGamma( bits );
	}
	labels.close();
	offsets.close();

	PrintWriter pw = new PrintWriter( new FileWriter( basename + "-fixedlabel" + ImmutableGraph.PROPERTIES_EXTENSION ) );
	pw.println( ImmutableGraph.GRAPHCLASS_PROPERTY_KEY + " = " + BitStreamArcLabelledImmutableGraph.class.getName() );
	pw.println( BitStreamArcLabelledImmutableGraph.LABELSPEC_PROPERTY_KEY + " = " + FakeCSFixedWidthIntLabel.class.getName() + "(TEST," + width + ")" );
	pw.println( ArcLabelledImmutableGraph.UNDERLYINGGRAPH_PROPERTY_KEY + " = " + basename.getName() );
	pw.close();
	
	return basename + "-fixedlabel";
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
public String createGraphWithFixedWidthListLabels( File basename, ImmutableGraph g, int width ) throws IllegalArgumentException, SecurityException, IOException {
	final int n = g.numNodes();
	System.err.println( "Testing " + n + " nodes, element width " + width+ ", basename " + basename );

	OutputBitStream labels = createTempBitStream( basename + "-fixedlistlabel" + BitStreamArcLabelledImmutableGraph.LABELS_EXTENSION );
	OutputBitStream offsets = createTempBitStream( basename + "-fixedlistlabel" + BitStreamArcLabelledImmutableGraph.LABEL_OFFSETS_EXTENSION );
	offsets.writeGamma( 0 );
	for( int i = 0; i < n; i++ ) {
		int bits = 0;
		for( IntIterator j = LazyIntIterators.eager( g.successors( i ) ); j.hasNext(); ) {
			int succ = j.nextInt();
			bits += labels.writeGamma( ( succ + 1 ) * 2  ); // list length
			for( int k = 0; k < ( succ + 1 ) * 2 ; k++ ) bits += labels.writeInt( i * k + i, width );
		}
		offsets.writeGamma( bits );
	}
	labels.close();
	offsets.close();

	PrintWriter pw = new PrintWriter( new FileWriter( basename + "-fixedlistlabel" + ImmutableGraph.PROPERTIES_EXTENSION ) );
	pw.println( ImmutableGraph.GRAPHCLASS_PROPERTY_KEY + " = " + BitStreamArcLabelledImmutableGraph.class.getName() );
	pw.println( BitStreamArcLabelledImmutableGraph.LABELSPEC_PROPERTY_KEY + " = " + FixedWidthIntListLabel.class.getName() + "(TEST," + width + ")" );
	pw.println( ArcLabelledImmutableGraph.UNDERLYINGGRAPH_PROPERTY_KEY + " = " + basename.getName() );
	pw.close();
	
	return basename + "-fixedlistlabel";
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
@Override
protected void write(OutputBitStream obs, int[] in, int offset, int len) throws IOException {
    for (int i = offset; i < offset + len; i++) {
        obs.writeZeta(in[i], k);
    }
}
 

import it.unimi.dsi.io.OutputBitStream; //导入依赖的package包/类
@Override
protected void write(OutputBitStream obs, int[] in, int offset, int len) throws IOException {
    for (int i = offset; i < offset + len; i++) {
        obs.writeGamma(in[i]);
    }
}