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Diffstat (limited to 'libjava/classpath/java/util/zip/OutputWindow.java')
| -rw-r--r-- | libjava/classpath/java/util/zip/OutputWindow.java | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/libjava/classpath/java/util/zip/OutputWindow.java b/libjava/classpath/java/util/zip/OutputWindow.java new file mode 100644 index 00000000000..1f082a9faa4 --- /dev/null +++ b/libjava/classpath/java/util/zip/OutputWindow.java @@ -0,0 +1,178 @@ +/* OutputWindow.java -- + Copyright (C) 2001, 2004 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package java.util.zip; + +/** + * Contains the output from the Inflation process. + * + * We need to have a window so that we can refer backwards into the output stream + * to repeat stuff. + * + * @author John Leuner + * @since 1.1 + */ +class OutputWindow +{ + private static final int WINDOW_SIZE = 1 << 15; + private static final int WINDOW_MASK = WINDOW_SIZE - 1; + + private byte[] window = new byte[WINDOW_SIZE]; //The window is 2^15 bytes + private int window_end = 0; + private int window_filled = 0; + + public void write(int abyte) + { + if (window_filled++ == WINDOW_SIZE) + throw new IllegalStateException("Window full"); + window[window_end++] = (byte) abyte; + window_end &= WINDOW_MASK; + } + + private void slowRepeat(int rep_start, int len, int dist) + { + while (len-- > 0) + { + window[window_end++] = window[rep_start++]; + window_end &= WINDOW_MASK; + rep_start &= WINDOW_MASK; + } + } + + public void repeat(int len, int dist) + { + if ((window_filled += len) > WINDOW_SIZE) + throw new IllegalStateException("Window full"); + + int rep_start = (window_end - dist) & WINDOW_MASK; + int border = WINDOW_SIZE - len; + if (rep_start <= border && window_end < border) + { + if (len <= dist) + { + System.arraycopy(window, rep_start, window, window_end, len); + window_end += len; + } + else + { + /* We have to copy manually, since the repeat pattern overlaps. + */ + while (len-- > 0) + window[window_end++] = window[rep_start++]; + } + } + else + slowRepeat(rep_start, len, dist); + } + + public int copyStored(StreamManipulator input, int len) + { + len = Math.min(Math.min(len, WINDOW_SIZE - window_filled), + input.getAvailableBytes()); + int copied; + + int tailLen = WINDOW_SIZE - window_end; + if (len > tailLen) + { + copied = input.copyBytes(window, window_end, tailLen); + if (copied == tailLen) + copied += input.copyBytes(window, 0, len - tailLen); + } + else + copied = input.copyBytes(window, window_end, len); + + window_end = (window_end + copied) & WINDOW_MASK; + window_filled += copied; + return copied; + } + + public void copyDict(byte[] dict, int offset, int len) + { + if (window_filled > 0) + throw new IllegalStateException(); + + if (len > WINDOW_SIZE) + { + offset += len - WINDOW_SIZE; + len = WINDOW_SIZE; + } + System.arraycopy(dict, offset, window, 0, len); + window_end = len & WINDOW_MASK; + } + + public int getFreeSpace() + { + return WINDOW_SIZE - window_filled; + } + + public int getAvailable() + { + return window_filled; + } + + public int copyOutput(byte[] output, int offset, int len) + { + int copy_end = window_end; + if (len > window_filled) + len = window_filled; + else + copy_end = (window_end - window_filled + len) & WINDOW_MASK; + + int copied = len; + int tailLen = len - copy_end; + + if (tailLen > 0) + { + System.arraycopy(window, WINDOW_SIZE - tailLen, + output, offset, tailLen); + offset += tailLen; + len = copy_end; + } + System.arraycopy(window, copy_end - len, output, offset, len); + window_filled -= copied; + if (window_filled < 0) + throw new IllegalStateException(); + return copied; + } + + public void reset() { + window_filled = window_end = 0; + } +} + + + |
