tikhomirov@51: /*
tikhomirov@576:  * Copyright (c) 2011-2013 TMate Software Ltd
tikhomirov@157:  *  
tikhomirov@157:  * This program is free software; you can redistribute it and/or modify
tikhomirov@157:  * it under the terms of the GNU General Public License as published by
tikhomirov@157:  * the Free Software Foundation; version 2 of the License.
tikhomirov@157:  *
tikhomirov@157:  * This program is distributed in the hope that it will be useful,
tikhomirov@157:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
tikhomirov@157:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
tikhomirov@157:  * GNU General Public License for more details.
tikhomirov@157:  *
tikhomirov@157:  * For information on how to redistribute this software under
tikhomirov@157:  * the terms of a license other than GNU General Public License
tikhomirov@157:  * contact TMate Software at support@hg4j.com
tikhomirov@51:  */
tikhomirov@157: package org.tmatesoft.hg.internal;
tikhomirov@51: 
tikhomirov@584: import java.io.EOFException;
tikhomirov@51: import java.io.IOException;
tikhomirov@576: import java.nio.ByteBuffer;
tikhomirov@51: import java.util.zip.DataFormatException;
tikhomirov@51: import java.util.zip.Inflater;
tikhomirov@51: import java.util.zip.ZipException;
tikhomirov@51: 
tikhomirov@51: /**
tikhomirov@51:  * DataAccess counterpart for InflaterInputStream.
tikhomirov@51:  * XXX is it really needed to be subclass of FilterDataAccess? 
tikhomirov@157:  *   
tikhomirov@157:  * @author Artem Tikhomirov
tikhomirov@157:  * @author TMate Software Ltd.
tikhomirov@51:  */
tikhomirov@51: public class InflaterDataAccess extends FilterDataAccess {
tikhomirov@51: 
tikhomirov@51: 	private final Inflater inflater;
tikhomirov@576: 	private final byte[] inBuffer;
tikhomirov@576: 	private final ByteBuffer outBuffer;
tikhomirov@576: 	private int inflaterPos = 0;
tikhomirov@158: 	private int decompressedLength;
tikhomirov@51: 
tikhomirov@420: 	public InflaterDataAccess(DataAccess dataAccess, long offset, int compressedLength) {
tikhomirov@263: 		this(dataAccess, offset, compressedLength, -1, new Inflater(), new byte[512]);
tikhomirov@51: 	}
tikhomirov@51: 
tikhomirov@420: 	public InflaterDataAccess(DataAccess dataAccess, long offset, int compressedLength, int actualLength) {
tikhomirov@263: 		this(dataAccess, offset, compressedLength, actualLength, new Inflater(), new byte[512]);
tikhomirov@158: 	}
tikhomirov@158: 
tikhomirov@420: 	public InflaterDataAccess(DataAccess dataAccess, long offset, int compressedLength, int actualLength, Inflater inflater, byte[] buf) {
tikhomirov@158: 		super(dataAccess, offset, compressedLength);
tikhomirov@263: 		if (inflater == null || buf == null) {
tikhomirov@263: 			throw new IllegalArgumentException();
tikhomirov@263: 		}
tikhomirov@51: 		this.inflater = inflater;
tikhomirov@158: 		this.decompressedLength = actualLength;
tikhomirov@576: 		inBuffer = buf;
tikhomirov@576: 		outBuffer = ByteBuffer.allocate(inBuffer.length * 2);
tikhomirov@576: 		outBuffer.limit(0); // there's nothing to read in the buffer 
tikhomirov@51: 	}
tikhomirov@51: 	
tikhomirov@51: 	@Override
tikhomirov@157: 	public InflaterDataAccess reset() throws IOException {
tikhomirov@51: 		super.reset();
tikhomirov@51: 		inflater.reset();
tikhomirov@576: 		inflaterPos = 0;
tikhomirov@576: 		outBuffer.clear().limit(0); // or flip(), to indicate nothing to read
tikhomirov@157: 		return this;
tikhomirov@51: 	}
tikhomirov@51: 	
tikhomirov@51: 	@Override
tikhomirov@421: 	protected int available() throws IOException {
tikhomirov@576: 		return length() - decompressedPosition();
tikhomirov@51: 	}
tikhomirov@51: 	
tikhomirov@51: 	@Override
tikhomirov@421: 	public boolean isEmpty() throws IOException {
tikhomirov@158: 		// can't use super.available() <= 0 because even when 0 < super.count < 6(?)
tikhomirov@158: 		// decompressedPos might be already == length() 
tikhomirov@158: 		return available() <= 0;
tikhomirov@51: 	}
tikhomirov@51: 	
tikhomirov@51: 	@Override
tikhomirov@421: 	public int length() throws IOException {
tikhomirov@51: 		if (decompressedLength != -1) {
tikhomirov@51: 			return decompressedLength;
tikhomirov@51: 		}
tikhomirov@576: 		decompressedLength = 0; // guard to avoid endless loop in case length() would get invoked from below.
tikhomirov@576: 		final int oldPos = decompressedPosition();
tikhomirov@576: 		final int inflatedUpTo = inflaterPos;
tikhomirov@576: 		int inflatedMore = 0, c;
tikhomirov@576: 		do {
tikhomirov@576: 			outBuffer.limit(outBuffer.position()); // pretend the buffer is consumed
tikhomirov@576: 			c = fillOutBuffer();
tikhomirov@576: 			inflatedMore += c;
tikhomirov@576: 		} while (c == outBuffer.capacity()); // once we unpacked less than capacity, input is over
tikhomirov@576: 		decompressedLength = inflatedUpTo + inflatedMore;
tikhomirov@421: 		reset();
tikhomirov@421: 		seek(oldPos);
tikhomirov@421: 		return decompressedLength;
tikhomirov@51: 	}
tikhomirov@51: 	
tikhomirov@51: 	@Override
tikhomirov@158: 	public void seek(int localOffset) throws IOException {
tikhomirov@51: 		if (localOffset < 0 /* || localOffset >= length() */) {
tikhomirov@51: 			throw new IllegalArgumentException();
tikhomirov@51: 		}
tikhomirov@576: 		int currentPos = decompressedPosition();
tikhomirov@576: 		if (localOffset >= currentPos) {
tikhomirov@576: 			skip(localOffset - currentPos);
tikhomirov@51: 		} else {
tikhomirov@51: 			reset();
tikhomirov@420: 			skip(localOffset);
tikhomirov@51: 		}
tikhomirov@51: 	}
tikhomirov@51: 	
tikhomirov@51: 	@Override
tikhomirov@391: 	public void skip(final int bytesToSkip) throws IOException {
tikhomirov@391: 		int bytes = bytesToSkip;
tikhomirov@51: 		if (bytes < 0) {
tikhomirov@576: 			bytes += decompressedPosition();
tikhomirov@51: 			if (bytes < 0) {
tikhomirov@576: 				throw new IOException(String.format("Underflow. Rewind past start of the slice. To skip:%d, decPos:%d, decLen:%d. Left:%d", bytesToSkip, inflaterPos, decompressedLength, bytes));
tikhomirov@51: 			}
tikhomirov@51: 			reset();
tikhomirov@51: 			// fall-through
tikhomirov@51: 		}
tikhomirov@51: 		while (!isEmpty() && bytes > 0) {
tikhomirov@576: 			int fromBuffer = outBuffer.remaining();
tikhomirov@576: 			if (fromBuffer > 0) {
tikhomirov@576: 				if (fromBuffer >= bytes) {
tikhomirov@576: 					outBuffer.position(outBuffer.position() + bytes);
tikhomirov@576: 					bytes = 0;
tikhomirov@576: 					break;
tikhomirov@576: 				} else {
tikhomirov@576: 					bytes -= fromBuffer;
tikhomirov@576: 					outBuffer.limit(outBuffer.position()); // mark consumed
tikhomirov@576: 					// fall through to fill the buffer
tikhomirov@576: 				}
tikhomirov@576: 			}
tikhomirov@576: 			fillOutBuffer();
tikhomirov@51: 		}
tikhomirov@51: 		if (bytes != 0) {
tikhomirov@576: 			throw new IOException(String.format("Underflow. Rewind past end of the slice. To skip:%d, decPos:%d, decLen:%d. Left:%d", bytesToSkip, inflaterPos, decompressedLength, bytes));
tikhomirov@51: 		}
tikhomirov@51: 	}
tikhomirov@51: 
tikhomirov@51: 	@Override
tikhomirov@51: 	public byte readByte() throws IOException {
tikhomirov@576: 		if (!outBuffer.hasRemaining()) {
tikhomirov@576: 			fillOutBuffer();
tikhomirov@576: 		}
tikhomirov@576: 		return outBuffer.get();
tikhomirov@51: 	}
tikhomirov@51: 
tikhomirov@51: 	@Override
tikhomirov@51: 	public void readBytes(byte[] b, int off, int len) throws IOException {
tikhomirov@584: 		int fromBuffer;
tikhomirov@576: 		do {
tikhomirov@584: 			fromBuffer = outBuffer.remaining();
tikhomirov@576: 			if (fromBuffer > 0) {
tikhomirov@576: 				if (fromBuffer >= len) {
tikhomirov@576: 					outBuffer.get(b, off, len);
tikhomirov@576: 					return;
tikhomirov@576: 				} else {
tikhomirov@576: 					outBuffer.get(b, off, fromBuffer);
tikhomirov@576: 					off += fromBuffer;
tikhomirov@576: 					len -= fromBuffer;
tikhomirov@576: 					// fall-through
tikhomirov@576: 				}
tikhomirov@576: 			}
tikhomirov@584: 			fromBuffer = fillOutBuffer();
tikhomirov@584: 		} while (len > 0 && fromBuffer > 0);
tikhomirov@584: 		if (len > 0) {
tikhomirov@584: 			// prevent hang up in this cycle if no more data is available, see Issue 25
tikhomirov@584: 			throw new EOFException(String.format("No more compressed data is available to satisfy request for %d bytes. [finished:%b, needDict:%b, needInp:%b, available:%d", len, inflater.finished(), inflater.needsDictionary(), inflater.needsInput(), super.available()));
tikhomirov@584: 		}
tikhomirov@576: 	}
tikhomirov@576: 	
tikhomirov@576: 	@Override
tikhomirov@576: 	public void readBytes(ByteBuffer buf) throws IOException {
tikhomirov@576: 		int len = Math.min(available(), buf.remaining());
tikhomirov@576: 		while (len > 0) {
tikhomirov@576: 			if (outBuffer.remaining() >= len) {
tikhomirov@576: 				ByteBuffer slice = outBuffer.slice();
tikhomirov@576: 				slice.limit(len);
tikhomirov@576: 				buf.put(slice);
tikhomirov@576: 				outBuffer.position(outBuffer.position() + len);
tikhomirov@576: 				return;
tikhomirov@576: 			} else { 
tikhomirov@576: 				len -= outBuffer.remaining();
tikhomirov@576: 				buf.put(outBuffer);
tikhomirov@576: 			}
tikhomirov@576: 			fillOutBuffer();
tikhomirov@576: 		}
tikhomirov@576: 	}
tikhomirov@576: 	
tikhomirov@576: 	private int decompressedPosition() {
tikhomirov@576: 		assert outBuffer.remaining() <= inflaterPos; 
tikhomirov@576: 		return inflaterPos - outBuffer.remaining();
tikhomirov@576: 	}
tikhomirov@576: 	
tikhomirov@576: 	// after #fillOutBuffer(), outBuffer is ready for read
tikhomirov@576: 	private int fillOutBuffer() throws IOException {
tikhomirov@576: 		assert !outBuffer.hasRemaining();
tikhomirov@51: 		try {
tikhomirov@576: 			int inflatedBytes = 0;
tikhomirov@576: 		    outBuffer.clear();
tikhomirov@576: 		    int len = outBuffer.capacity();
tikhomirov@576: 		    int off = 0;
tikhomirov@576: 		    do {
tikhomirov@576: 			    int n;
tikhomirov@576: 			    while ((n = inflater.inflate(outBuffer.array(), off, len)) == 0) {
tikhomirov@399: 			    	// XXX few last bytes (checksum?) may be ignored by inflater, thus inflate may return 0 in
tikhomirov@157: 			    	// perfectly legal conditions (when all data already expanded, but there are still some bytes
tikhomirov@399: 			    	// in the input stream)
tikhomirov@399: 					int toRead = -1;
tikhomirov@399: 					if (inflater.needsInput() && (toRead = super.available()) > 0) {
tikhomirov@576: 						// fill
tikhomirov@576: 						if (toRead > inBuffer.length) {
tikhomirov@576: 							toRead = inBuffer.length;
tikhomirov@51: 						}
tikhomirov@576: 						super.readBytes(inBuffer, 0, toRead);
tikhomirov@576: 						inflater.setInput(inBuffer, 0, toRead);
tikhomirov@399: 					} else {
tikhomirov@576: 						// inflated nothing and doesn't want any more data (or no date available) - assume we're done 
tikhomirov@576: 						assert inflater.finished();
tikhomirov@576: 						assert toRead <= 0;
tikhomirov@576: 						break;
tikhomirov@51: 					}
tikhomirov@51: 			    }
tikhomirov@51: 				off += n;
tikhomirov@51: 				len -= n;
tikhomirov@576: 				inflatedBytes += n;
tikhomirov@576: 		    } while (len > 0 && !inflater.finished()); // either the buffer is filled or nothing more to unpack
tikhomirov@576: 		    inflaterPos += inflatedBytes;
tikhomirov@576: 		    outBuffer.limit(inflatedBytes);
tikhomirov@576: 		    assert outBuffer.position() == 0; // didn't change since #clear() above
tikhomirov@576: 		    return inflatedBytes;
tikhomirov@51: 		} catch (DataFormatException e) {
tikhomirov@51: 		    String s = e.getMessage();
tikhomirov@51: 		    throw new ZipException(s != null ? s : "Invalid ZLIB data format");
tikhomirov@51: 		}
tikhomirov@51:     }
tikhomirov@51: }