tikhomirov@51: /*
tikhomirov@420:  * Copyright (c) 2011-2012 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@51: import java.io.EOFException;
tikhomirov@51: import java.io.IOException;
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@51: 	private final byte[] buffer;
tikhomirov@51: 	private final byte[] singleByte = new byte[1];
tikhomirov@51: 	private int decompressedPos = 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@263: 		buffer = buf;
tikhomirov@51: 	}
tikhomirov@51: 	
tikhomirov@51: 	@Override
tikhomirov@157: 	public InflaterDataAccess reset() throws IOException {
tikhomirov@51: 		super.reset();
tikhomirov@51: 		inflater.reset();
tikhomirov@51: 		decompressedPos = 0;
tikhomirov@157: 		return this;
tikhomirov@51: 	}
tikhomirov@51: 	
tikhomirov@51: 	@Override
tikhomirov@421: 	protected int available() throws IOException {
tikhomirov@158: 		return length() - decompressedPos;
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@158: 		decompressedLength = 0; // guard to avoid endless loop in case length() would get invoked from below. 
tikhomirov@51: 		int c = 0;
tikhomirov@421: 		int oldPos = decompressedPos;
tikhomirov@421: 		byte[] dummy = new byte[buffer.length];
tikhomirov@575: 		try {
tikhomirov@575: 			int toRead = -1;
tikhomirov@575: 			do {
tikhomirov@421: 				while (!inflater.needsInput()) {
tikhomirov@421: 					c += inflater.inflate(dummy, 0, dummy.length);
tikhomirov@158: 				}
tikhomirov@575: 				if (inflater.needsInput() && (toRead = super.available()) > 0) {
tikhomirov@575: 					// fill:
tikhomirov@575: 					if (toRead > buffer.length) {
tikhomirov@575: 						toRead = buffer.length;
tikhomirov@575: 					}
tikhomirov@575: 					super.readBytes(buffer, 0, toRead);
tikhomirov@575: 					inflater.setInput(buffer, 0, toRead);
tikhomirov@575: 				}
tikhomirov@575: 			} while(toRead > 0);
tikhomirov@575: 		} catch (DataFormatException ex) {
tikhomirov@575: 			throw new IOException(ex.toString());
tikhomirov@51: 		}
tikhomirov@421: 		decompressedLength = c + oldPos;
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@51: 		if (localOffset >= decompressedPos) {
tikhomirov@420: 			skip(localOffset - decompressedPos);
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@51: 			bytes += decompressedPos;
tikhomirov@51: 			if (bytes < 0) {
tikhomirov@391: 				throw new IOException(String.format("Underflow. Rewind past start of the slice. To skip:%d, decPos:%d, decLen:%d. Left:%d", bytesToSkip, decompressedPos, decompressedLength, bytes));
tikhomirov@51: 			}
tikhomirov@51: 			reset();
tikhomirov@51: 			// fall-through
tikhomirov@51: 		}
tikhomirov@51: 		while (!isEmpty() && bytes > 0) {
tikhomirov@51: 			readByte();
tikhomirov@51: 			bytes--;
tikhomirov@51: 		}
tikhomirov@51: 		if (bytes != 0) {
tikhomirov@391: 			throw new IOException(String.format("Underflow. Rewind past end of the slice. To skip:%d, decPos:%d, decLen:%d. Left:%d", bytesToSkip, decompressedPos, decompressedLength, bytes));
tikhomirov@51: 		}
tikhomirov@51: 	}
tikhomirov@51: 
tikhomirov@51: 	@Override
tikhomirov@51: 	public byte readByte() throws IOException {
tikhomirov@51: 		readBytes(singleByte, 0, 1);
tikhomirov@51: 		return singleByte[0];
tikhomirov@51: 	}
tikhomirov@51: 
tikhomirov@51: 	@Override
tikhomirov@51: 	public void readBytes(byte[] b, int off, int len) throws IOException {
tikhomirov@51: 		try {
tikhomirov@51: 		    int n;
tikhomirov@51: 		    while (len > 0) {
tikhomirov@51: 			    while ((n = inflater.inflate(b, 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@51: 						// fill:
tikhomirov@51: 						if (toRead > buffer.length) {
tikhomirov@51: 							toRead = buffer.length;
tikhomirov@51: 						}
tikhomirov@51: 						super.readBytes(buffer, 0, toRead);
tikhomirov@51: 						inflater.setInput(buffer, 0, toRead);
tikhomirov@399: 					} else {
tikhomirov@399: 						// prevent hang up in this cycle if no more data is available, see Issue 25
tikhomirov@399: 						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(), toRead));
tikhomirov@51: 					}
tikhomirov@51: 			    }
tikhomirov@51: 				off += n;
tikhomirov@51: 				len -= n;
tikhomirov@51: 				decompressedPos += n;
tikhomirov@51: 				if (len == 0) {
tikhomirov@51: 					return; // filled
tikhomirov@51: 				}
tikhomirov@51: 		    }
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: }