| /* CompressedInputStream.java -- |
| Copyright (C) 2003, 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 gnu.java.net.protocol.ftp; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.net.ProtocolException; |
| |
| /** |
| * A DTP input stream that implements the FTP compressed transfer mode. |
| * |
| * @author Chris Burdess (dog@gnu.org) |
| */ |
| class CompressedInputStream |
| extends DTPInputStream |
| { |
| |
| static final int EOF = 64; |
| |
| static final int RAW = 0x00; |
| static final int COMPRESSED = 0x80; |
| static final int FILLER = 0xc0; |
| |
| int descriptor; |
| int max = -1; |
| int count = -1; |
| |
| int state = RAW; // RAW | STATE | FILLER |
| int rep; // the compressed byte |
| int n = 0; // the number of compressed or raw bytes |
| |
| CompressedInputStream(DTP dtp, InputStream in) |
| { |
| super(dtp, in); |
| } |
| |
| public int read() |
| throws IOException |
| { |
| if (transferComplete) |
| { |
| return -1; |
| } |
| if (count == -1) |
| { |
| readHeader(); |
| } |
| if (max < 1) |
| { |
| close(); |
| return -1; |
| } |
| if (n > 0 && (state == COMPRESSED || state == FILLER)) |
| { |
| n--; |
| return rep; |
| } |
| int c = in.read(); |
| if (c == -1) |
| { |
| close(); |
| } |
| count++; |
| if (count >= max) |
| { |
| count = -1; |
| if (descriptor == EOF) |
| { |
| close(); |
| } |
| } |
| if (c == -1) |
| { |
| return c; |
| } |
| while (n == 0) // read code header |
| { |
| state = (c & 0xc0); |
| n = (c & 0x3f); |
| c = in.read(); |
| if (c == -1) |
| { |
| return -1; |
| } |
| } |
| switch (state) |
| { |
| case RAW: |
| break; |
| case COMPRESSED: |
| case FILLER: |
| rep = c; |
| break; |
| default: |
| throw new ProtocolException("Illegal state: " + state); |
| } |
| n--; |
| return c; |
| } |
| |
| public int read(byte[] buf) |
| throws IOException |
| { |
| return read(buf, 0, buf.length); |
| } |
| |
| public int read(byte[] buf, int off, int len) |
| throws IOException |
| { |
| if (transferComplete) |
| { |
| return -1; |
| } |
| if (count == -1) |
| { |
| readHeader(); |
| } |
| if (max < 1) |
| { |
| close(); |
| return -1; |
| } |
| // TODO improve performance |
| for (int i = off; i < len; i++) |
| { |
| int c = read(); |
| if (c == -1) |
| { |
| close(); |
| return i; |
| } |
| buf[i] = (byte) c; |
| } |
| return len; |
| /* |
| int l = in.read (buf, off, len); |
| if (l==-1) |
| { |
| close (); |
| } |
| count += l; |
| if (count>=max) |
| { |
| count = -1; |
| if (descriptor==EOF) |
| { |
| close (); |
| } |
| } |
| return l; |
| */ |
| } |
| |
| /** |
| * Reads the block header. |
| */ |
| void readHeader() |
| throws IOException |
| { |
| descriptor = in.read(); |
| int max_hi = in.read(); |
| int max_lo = in.read(); |
| max = (max_hi << 8) | max_lo; |
| count = 0; |
| } |
| |
| /** |
| * Reads the code header. |
| */ |
| void readCodeHeader() |
| throws IOException |
| { |
| int code = in.read(); |
| state = (code & 0xc0); |
| n = (code & 0x3f); |
| } |
| |
| } |
| |