| /* |
| * Copyright (C) 2008-2009, Google Inc. |
| * Copyright (C) 2006-2008, Shawn O. Pearce <spearce@spearce.org> |
| * and other copyright owners as documented in the project's IP log. |
| * |
| * This program and the accompanying materials are made available |
| * under the terms of the Eclipse Distribution License v1.0 which |
| * accompanies this distribution, is reproduced below, and is |
| * available at http://www.eclipse.org/org/documents/edl-v10.php |
| * |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or |
| * without modification, are permitted provided that the following |
| * conditions are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * - Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer in the documentation and/or other materials provided |
| * with the distribution. |
| * |
| * - Neither the name of the Eclipse Foundation, Inc. nor the |
| * names of its contributors may be used to endorse or promote |
| * products derived from this software without specific prior |
| * written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND |
| * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, |
| * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package org.eclipse.jgit.lib; |
| |
| import java.io.IOException; |
| import java.util.zip.DataFormatException; |
| import java.util.zip.Inflater; |
| |
| /** Active handle to a ByteWindow. */ |
| public final class WindowCursor { |
| /** Temporary buffer large enough for at least one raw object id. */ |
| final byte[] tempId = new byte[Constants.OBJECT_ID_LENGTH]; |
| |
| private Inflater inf; |
| |
| private ByteWindow window; |
| |
| /** |
| * Copy bytes from the window to a caller supplied buffer. |
| * |
| * @param pack |
| * the file the desired window is stored within. |
| * @param position |
| * position within the file to read from. |
| * @param dstbuf |
| * destination buffer to copy into. |
| * @param dstoff |
| * offset within <code>dstbuf</code> to start copying into. |
| * @param cnt |
| * number of bytes to copy. This value may exceed the number of |
| * bytes remaining in the window starting at offset |
| * <code>pos</code>. |
| * @return number of bytes actually copied; this may be less than |
| * <code>cnt</code> if <code>cnt</code> exceeded the number of |
| * bytes available. |
| * @throws IOException |
| * this cursor does not match the provider or id and the proper |
| * window could not be acquired through the provider's cache. |
| */ |
| int copy(final PackFile pack, long position, final byte[] dstbuf, |
| int dstoff, final int cnt) throws IOException { |
| final long length = pack.length; |
| int need = cnt; |
| while (need > 0 && position < length) { |
| pin(pack, position); |
| final int r = window.copy(position, dstbuf, dstoff, need); |
| position += r; |
| dstoff += r; |
| need -= r; |
| } |
| return cnt - need; |
| } |
| |
| /** |
| * Pump bytes into the supplied inflater as input. |
| * |
| * @param pack |
| * the file the desired window is stored within. |
| * @param position |
| * position within the file to read from. |
| * @param dstbuf |
| * destination buffer the inflater should output decompressed |
| * data to. |
| * @param dstoff |
| * current offset within <code>dstbuf</code> to inflate into. |
| * @return updated <code>dstoff</code> based on the number of bytes |
| * successfully inflated into <code>dstbuf</code>. |
| * @throws IOException |
| * this cursor does not match the provider or id and the proper |
| * window could not be acquired through the provider's cache. |
| * @throws DataFormatException |
| * the inflater encountered an invalid chunk of data. Data |
| * stream corruption is likely. |
| */ |
| int inflate(final PackFile pack, long position, final byte[] dstbuf, |
| int dstoff) throws IOException, DataFormatException { |
| if (inf == null) |
| inf = InflaterCache.get(); |
| else |
| inf.reset(); |
| for (;;) { |
| pin(pack, position); |
| dstoff = window.inflate(position, dstbuf, dstoff, inf); |
| if (inf.finished()) |
| return dstoff; |
| position = window.end; |
| } |
| } |
| |
| void inflateVerify(final PackFile pack, long position) |
| throws IOException, DataFormatException { |
| if (inf == null) |
| inf = InflaterCache.get(); |
| else |
| inf.reset(); |
| for (;;) { |
| pin(pack, position); |
| window.inflateVerify(position, inf); |
| if (inf.finished()) |
| return; |
| position = window.end; |
| } |
| } |
| |
| private void pin(final PackFile pack, final long position) |
| throws IOException { |
| final ByteWindow w = window; |
| if (w == null || !w.contains(pack, position)) { |
| // If memory is low, we may need what is in our window field to |
| // be cleaned up by the GC during the get for the next window. |
| // So we always clear it, even though we are just going to set |
| // it again. |
| // |
| window = null; |
| window = WindowCache.get(pack, position); |
| } |
| } |
| |
| /** Release the current window cursor. */ |
| public void release() { |
| window = null; |
| try { |
| InflaterCache.release(inf); |
| } finally { |
| inf = null; |
| } |
| } |
| |
| /** |
| * @param curs cursor to release; may be null. |
| * @return always null. |
| */ |
| public static WindowCursor release(final WindowCursor curs) { |
| if (curs != null) |
| curs.release(); |
| return null; |
| } |
| } |