CompressOutputStream.java revision 0
0N/A/*
0N/A * Copyright 1998 Sun Microsystems, Inc. All Rights Reserved.
0N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
0N/A *
0N/A * This code is free software; you can redistribute it and/or modify it
0N/A * under the terms of the GNU General Public License version 2 only, as
0N/A * published by the Free Software Foundation.
0N/A *
0N/A * This code is distributed in the hope that it will be useful, but WITHOUT
0N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
0N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
0N/A * version 2 for more details (a copy is included in the LICENSE file that
0N/A * accompanied this code).
0N/A *
0N/A * You should have received a copy of the GNU General Public License version
0N/A * 2 along with this work; if not, write to the Free Software Foundation,
0N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
0N/A *
0N/A * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
0N/A * CA 95054 USA or visit www.sun.com if you need additional information or
0N/A * have any questions.
0N/A */
0N/A
0N/A/*
0N/A */
0N/A
0N/Aimport java.io.*;
0N/A
0N/Aclass CompressOutputStream extends FilterOutputStream
0N/A implements CompressConstants
0N/A{
0N/A
0N/A public CompressOutputStream(OutputStream out) {
0N/A super(out);
0N/A }
0N/A
0N/A // buffer of 6-bit codes to pack into next 32-bit word
0N/A int buf[] = new int[5];
0N/A
0N/A // number of valid codes pending in buffer
0N/A int bufPos = 0;
0N/A
0N/A public void write(int b) throws IOException {
0N/A b &= 0xFF; // force argument to a byte
0N/A
0N/A int pos = codeTable.indexOf((char)b);
0N/A if (pos != -1)
0N/A writeCode(BASE + pos);
0N/A else {
0N/A writeCode(RAW);
0N/A writeCode(b >> 4);
0N/A writeCode(b & 0xF);
0N/A }
0N/A }
0N/A
0N/A public void write(byte b[], int off, int len) throws IOException {
0N/A /*
0N/A * This is quite an inefficient implementation, because it has to
0N/A * call the other write method for every byte in the array. It
0N/A * could be optimized for performance by doing all the processing
0N/A * in this method.
0N/A */
0N/A for (int i = 0; i < len; i++)
0N/A write(b[off + i]);
0N/A }
0N/A
0N/A public void flush() throws IOException {
0N/A while (bufPos > 0)
0N/A writeCode(NOP);
0N/A }
0N/A
0N/A private void writeCode(int c) throws IOException {
0N/A buf[bufPos++] = c;
0N/A if (bufPos == 5) { // write next word when we have 5 codes
0N/A int pack = (buf[0] << 24) | (buf[1] << 18) | (buf[2] << 12) |
0N/A (buf[3] << 6) | buf[4];
0N/A out.write((pack >>> 24) & 0xFF);
0N/A out.write((pack >>> 16) & 0xFF);
0N/A out.write((pack >>> 8) & 0xFF);
0N/A out.write((pack >>> 0) & 0xFF);
0N/A bufPos = 0;
0N/A }
0N/A }
0N/A}