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	/*
	* Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package jdk.jfr.internal.consumer;

	import java.io.DataInput;
	import java.io.IOException;

	import jdk.jfr.internal.LogLevel;
	import jdk.jfr.internal.LogTag;
	import jdk.jfr.internal.Logger;
	import jdk.jfr.internal.MetadataDescriptor;

	public final class ChunkHeader {
	private static final long METADATA_TYPE_ID = 0;
	private static final byte[] FILE_MAGIC = { 'F', 'L', 'R', '\0' };

	private final short major;
	private final short minor;
	private final long chunkSize;
	private final long chunkStartTicks;
	private final long ticksPerSecond;
	private final long chunkStartNanos;
	private final long metadataPosition;
	// private final long absoluteInitialConstantPoolPosition;
	private final long absoluteChunkEnd;
	private final long absoluteEventStart;
	private final long absoluteChunkStart;
	private final boolean lastChunk;
	private final RecordingInput input;
	private final long durationNanos;
	private final long id;
	private long constantPoolPosition;

	public ChunkHeader(RecordingInput input) throws IOException {
	this(input, 0, 0);
	}

	private ChunkHeader(RecordingInput input, long absoluteChunkStart, long id) throws IOException {
	input.position(absoluteChunkStart);
	if (input.position() >= input.size()) {
	throw new IOException("Chunk contains no data");
	}
	verifyMagic(input);
	this.input = input;
	this.id = id;
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk " + id);
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: startPosition=" + absoluteChunkStart);
	major = input.readRawShort();
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: major=" + major);
	minor = input.readRawShort();
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: minor=" + minor);
	if (major != 1 && major != 2) {
	throw new IOException("File version " + major + "." + minor + ". Only Flight Recorder files of version 1.x and 2.x can be read by this JDK.");
	}
	chunkSize = input.readRawLong();
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: chunkSize=" + chunkSize);
	this.constantPoolPosition = input.readRawLong();
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: constantPoolPosition=" + constantPoolPosition);
	metadataPosition = input.readRawLong();
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: metadataPosition=" + metadataPosition);
	chunkStartNanos = input.readRawLong(); // nanos since epoch
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: startNanos=" + chunkStartNanos);
	durationNanos = input.readRawLong(); // duration nanos, not used
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: durationNanos=" + durationNanos);
	chunkStartTicks = input.readRawLong();
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: startTicks=" + chunkStartTicks);
	ticksPerSecond = input.readRawLong();
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.INFO, "Chunk: ticksPerSecond=" + ticksPerSecond);
	input.readRawInt(); // features, not used

	// set up boundaries
	this.absoluteChunkStart = absoluteChunkStart;
	absoluteChunkEnd = absoluteChunkStart + chunkSize;
	lastChunk = input.size() == absoluteChunkEnd;
	absoluteEventStart = input.position();

	// read metadata
	input.position(absoluteEventStart);
	}

	public ChunkHeader nextHeader() throws IOException {
	return new ChunkHeader(input, absoluteChunkEnd, id + 1);
	}

	public MetadataDescriptor readMetadata() throws IOException {
	input.position(absoluteChunkStart + metadataPosition);
	input.readInt(); // size
	long id = input.readLong(); // event type id
	if (id != METADATA_TYPE_ID) {
	throw new IOException("Expected metadata event. Type id=" + id + ", should have been " + METADATA_TYPE_ID);
	}
	input.readLong(); // start time
	input.readLong(); // duration
	long metadataId = input.readLong();
	Logger.log(LogTag.JFR_SYSTEM_PARSER, LogLevel.TRACE, "Metadata id=" + metadataId);
	// No need to read if metadataId == lastMetadataId, but we
	// do it for verification purposes.
	return MetadataDescriptor.read(input);
	}

	public boolean isLastChunk() {
	return lastChunk;
	}

	public short getMajor() {
	return major;
	}

	public short getMinor() {
	return minor;
	}

	public long getAbsoluteChunkStart() {
	return absoluteChunkStart;
	}

	public long getConstantPoolPosition() {
	return constantPoolPosition;
	}

	public long getStartTicks() {
	return chunkStartTicks;
	}

	public double getTicksPerSecond() {
	return ticksPerSecond;
	}

	public long getStartNanos() {
	return chunkStartNanos;
	}

	public long getEnd() {
	return absoluteChunkEnd;
	}

	public long getSize() {
	return chunkSize;
	}

	public long getDurationNanos() {
	return durationNanos;
	}

	public RecordingInput getInput() {
	return input;
	}

	private static void verifyMagic(DataInput input) throws IOException {
	for (byte c : FILE_MAGIC) {
	if (input.readByte() != c) {
	throw new IOException("Not a Flight Recorder file");
	}
	}
	}

	public long getEventStart() {
	return absoluteEventStart;
	}

	}

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