/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

/*

 */

import java.io.*;

class CompressInputStream extends FilterInputStream

    implements CompressConstants

{

    public CompressInputStream(InputStream in) {

        super(in);

    }

    // buffer of unpacked 6-bit codes from last 32-word read

    int buf[] = new int[5];

    // position of next code to read in buffer (5 == end of buffer)

    int bufPos = 5;

    public int read() throws IOException {

        try {

            int code;

            do {

                code = readCode();

            } while (code == NOP);      // ignore NOP codes

            if (code >= BASE)

                return codeTable.charAt(code - BASE);

            else if (code == RAW) {

                int high = readCode();

                int low = readCode();

                return (high << 4) | low;

            } else

                throw new IOException("unknown compression code: " + code);

        } catch (EOFException e) {

            return -1;

        }

    }

    public int read(byte b[], int off, int len) throws IOException {

        if (len <= 0) {

            return 0;

        }

        int c = read();

        if (c == -1) {

            return -1;

        }

        b[off] = (byte)c;

        int i = 1;

/*****

        try {

            for (; i < len ; i++) {

                c = read();

                if (c == -1) {

                    break;

                }

                if (b != null) {

                    b[off + i] = (byte)c;

                }

            }

        } catch (IOException ee) {

        }

 *****/

        return i;

    }

    private int readCode() throws IOException {

        if (bufPos == 5) {

            int b1 = in.read();

            int b2 = in.read();

            int b3 = in.read();

            int b4 = in.read();

            if ((b1 | b2 | b3 | b4) < 0)

                throw new EOFException();

            int pack = (b1 << 24) | (b2 << 16) | (b3 << 8) | b4;

            buf[0] = (pack >>> 24) & 0x3F;

            buf[1] = (pack >>> 18) & 0x3F;

            buf[2] = (pack >>> 12) & 0x3F;

            buf[3] = (pack >>>  6) & 0x3F;

            buf[4] = (pack >>>  0) & 0x3F;

            bufPos = 0;

        }

        return buf[bufPos++];

    }

}