package org.bouncycastle.util.encoders;/** * a buffering class to allow translation from one format to another to * be done in discrete chunks. */public class BufferedDecoder{    protected byte[]        buf;    protected int           bufOff;    protected Translator    translator;    /**     * @param translator the translator to use.     * @param bufSize amount of input to buffer for each chunk.     */    public BufferedDecoder(        Translator  translator,        int         bufSize)    {        this.translator = translator;        if ((bufSize % translator.getEncodedBlockSize()) != 0)        {            throw new IllegalArgumentException("buffer size not multiple of input block size");        }        buf = new byte[bufSize];        bufOff = 0;    }    public int processByte(        byte        in,        byte[]      out,        int         outOff)    {        int         resultLen = 0;        buf[bufOff++] = in;        if (bufOff == buf.length)        {            resultLen = translator.decode(buf, 0, buf.length, out, outOff);            bufOff = 0;        }        return resultLen;    }    public int processBytes(        byte[]      in,        int         inOff,        int         len,        byte[]      out,        int         outOff)    {        if (len < 0)        {            throw new IllegalArgumentException("Can't have a negative input length!");        }        int resultLen = 0;        int gapLen = buf.length - bufOff;        if (len > gapLen)        {            System.arraycopy(in, inOff, buf, bufOff, gapLen);            resultLen += translator.decode(buf, 0, buf.length, out, outOff);            bufOff = 0;            len -= gapLen;            inOff += gapLen;            outOff += resultLen;            int chunkSize = len - (len % buf.length);            resultLen += translator.decode(in, inOff, chunkSize, out, outOff);            len -= chunkSize;            inOff += chunkSize;        }        if (len != 0)        {            System.arraycopy(in, inOff, buf, bufOff, len);            bufOff += len;        }        return resultLen;    }}