public SessionInputBufferImpl(int buffersize,
    int linebuffersize,
    HttpParams params) 
{
        this(buffersize, linebuffersize, new HeapByteBufferAllocator(), params);
}

 public SessionInputBufferImpl(int buffersize,
    int linebuffersize,
    ByteBufferAllocator allocator,
    HttpParams params) 
{
        super(buffersize, allocator);
        this.charbuffer = CharBuffer.allocate(linebuffersize);
        this.charset = Charset.forName(HttpProtocolParams.getHttpElementCharset(params)); 
        this.chardecoder = this.charset.newDecoder();
}

 public int fill(ReadableByteChannel channel) throws IOException 
{
        if (channel == null) {
            throw new IllegalArgumentException("Channel may not be null");
        }
        setInputMode();
        if (!this.buffer.hasRemaining()) {
            expand();
        }
        int readNo = channel.read(this.buffer);
        return readNo;
}

 public int read() 
{
        setOutputMode();
        return this.buffer.get() & 0xff;
}

 public int read(ByteBuffer dst) 
{
        if (dst == null) {
            return 0;
        }
        return read(dst, dst.remaining());
}

 public int read(WritableByteChannel dst) throws IOException 
{
        if (dst == null) {
            return 0;
        }
        setOutputMode();
        return dst.write(this.buffer);
}

 public int read(ByteBuffer dst,
    int maxLen) 
{
        if (dst == null) {
            return 0;
        }
        setOutputMode();
        int len = Math.min(dst.remaining(), maxLen);
        int chunk = Math.min(this.buffer.remaining(), len);
        for (int i = 0; i <  chunk; i++) {
            dst.put(this.buffer.get());
        }
        return chunk;
}

 public int read(WritableByteChannel dst,
    int maxLen) throws IOException 
{
        if (dst == null) {
            return 0;
        }
        setOutputMode();
        int bytesRead;
        if (this.buffer.remaining()  > maxLen) {
            int oldLimit = this.buffer.limit();
            int newLimit = oldLimit - (this.buffer.remaining() - maxLen);
            this.buffer.limit(newLimit);
            bytesRead = dst.write(this.buffer);
            this.buffer.limit(oldLimit);
        } else {
            bytesRead = dst.write(this.buffer);
        }
        return bytesRead;
}

 public String readLine(boolean endOfStream) throws CharacterCodingException 
{
        CharArrayBuffer charbuffer = new CharArrayBuffer(64);
        boolean found = readLine(charbuffer, endOfStream);
        if (found) {
            return charbuffer.toString();
        } else {
            return null;
        }
}

 public boolean readLine(CharArrayBuffer linebuffer,
    boolean endOfStream) throws CharacterCodingException 
{
        
        setOutputMode();
        // See if there is LF char present in the buffer
        int pos = -1;
        boolean hasLine = false;
        for (int i = this.buffer.position(); i <  this.buffer.limit(); i++) {
            int b = this.buffer.get(i);
            if (b == HTTP.LF) {
                hasLine = true;
                pos = i + 1;
                break;
            }
        }
        if (!hasLine) {
            if (endOfStream && this.buffer.hasRemaining()) {
                // No more data. Get the rest
                pos = this.buffer.limit();
            } else {
                // Either no complete line present in the buffer 
                // or no more data is expected
                return false;
            }
        }
        int origLimit = this.buffer.limit();
        this.buffer.limit(pos);
        int len = this.buffer.limit() - this.buffer.position();
        // Ensure capacity of len assuming ASCII as the most likely charset
        linebuffer.ensureCapacity(len);
        this.chardecoder.reset();
        for (;;) {
            CoderResult result = this.chardecoder.decode(
                    this.buffer, 
                    this.charbuffer, 
                    true);
            if (result.isError()) {
                result.throwException();
            }
            if (result.isOverflow()) {
                this.charbuffer.flip();
                linebuffer.append(
                        this.charbuffer.array(), 
                        this.charbuffer.position(), 
                        this.charbuffer.remaining());
                this.charbuffer.clear();
            }
            if (result.isUnderflow()) {
                break;
            }
        }
        this.buffer.limit(origLimit);
        // flush the decoder
        this.chardecoder.flush(this.charbuffer);
        this.charbuffer.flip();
        // append the decoded content to the line buffer
        if (this.charbuffer.hasRemaining()) {
            linebuffer.append(
                    this.charbuffer.array(), 
                    this.charbuffer.position(), 
                    this.charbuffer.remaining());
        }
        // discard LF if found
        int l = linebuffer.length(); 
        if (l  > 0) {
            if (linebuffer.charAt(l - 1) == HTTP.LF) {
                l--;
                linebuffer.setLength(l);
            }
            // discard CR if found
            if (l  > 0) {
                if (linebuffer.charAt(l - 1) == HTTP.CR) {
                    l--;
                    linebuffer.setLength(l);
                }
            }
        }
        return true;
}