/* -*-mode:java; c-basic-offset:2; indent-tabs-mode:nil -*- */
/* JOrbis
 * Copyright (C) 2000 ymnk, JCraft,Inc.
 *  
 * Written by: 2000 ymnk<ymnk@jcraft.com>
 *   
 * Many thanks to 
 *   Monty <monty@xiph.org> and 
 *   The XIPHOPHORUS Company http://www.xiph.org/ .
 * JOrbis has been based on their awesome works, Vorbis codec.
 *   
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public License
 * as published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.

 * This program 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 Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

package com.jcraft.jogg;

public class Buffer {
	private static final int BUFFER_INCREMENT = 256;

	private static final int[] mask = { 0x00000000, 0x00000001, 0x00000003,
			0x00000007, 0x0000000f, 0x0000001f, 0x0000003f, 0x0000007f,
			0x000000ff, 0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
			0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff, 0x0001ffff,
			0x0003ffff, 0x0007ffff, 0x000fffff, 0x001fffff, 0x003fffff,
			0x007fffff, 0x00ffffff, 0x01ffffff, 0x03ffffff, 0x07ffffff,
			0x0fffffff, 0x1fffffff, 0x3fffffff, 0x7fffffff, 0xffffffff };

	int ptr = 0;
	byte[] buffer = null;
	int endbit = 0;
	int endbyte = 0;
	int storage = 0;

	public void writeinit() {
		buffer = new byte[BUFFER_INCREMENT];
		ptr = 0;
		buffer[0] = (byte) '\0';
		storage = BUFFER_INCREMENT;
	}

	public void write(byte[] s) {
		for (int i = 0; i < s.length; i++) {
			if (s[i] == 0)
				break;
			write(s[i], 8);
		}
	}

	public void read(byte[] s, int bytes) {
		int i = 0;
		while (bytes-- != 0) {
			s[i++] = (byte) (read(8));
		}
	}

	void reset() {
		ptr = 0;
		buffer[0] = (byte) '\0';
		endbit = endbyte = 0;
	}

	public void writeclear() {
		buffer = null;
	}

	public void readinit(byte[] buf, int bytes) {
		readinit(buf, 0, bytes);
	}

	public void readinit(byte[] buf, int start, int bytes) {
		ptr = start;
		buffer = buf;
		endbit = endbyte = 0;
		storage = bytes;
	}

	public void write(int value, int bits) {
		if (endbyte + 4 >= storage) {
			byte[] foo = new byte[storage + BUFFER_INCREMENT];
			System.arraycopy(buffer, 0, foo, 0, storage);
			buffer = foo;
			storage += BUFFER_INCREMENT;
		}

		value &= mask[bits];
		bits += endbit;
		buffer[ptr] |= (byte) (value << endbit);

		if (bits >= 8) {
			buffer[ptr + 1] = (byte) (value >>> (8 - endbit));
			if (bits >= 16) {
				buffer[ptr + 2] = (byte) (value >>> (16 - endbit));
				if (bits >= 24) {
					buffer[ptr + 3] = (byte) (value >>> (24 - endbit));
					if (bits >= 32) {
						if (endbit > 0)
							buffer[ptr + 4] = (byte) (value >>> (32 - endbit));
						else
							buffer[ptr + 4] = 0;
					}
				}
			}
		}

		endbyte += bits / 8;
		ptr += bits / 8;
		endbit = bits & 7;
	}

	public int look(int bits) {
		int ret;
		int m = mask[bits];

		bits += endbit;

		if (endbyte + 4 >= storage) {
			if (endbyte + (bits - 1) / 8 >= storage)
				return (-1);
		}

		ret = ((buffer[ptr]) & 0xff) >>> endbit;
		if (bits > 8) {
			ret |= ((buffer[ptr + 1]) & 0xff) << (8 - endbit);
			if (bits > 16) {
				ret |= ((buffer[ptr + 2]) & 0xff) << (16 - endbit);
				if (bits > 24) {
					ret |= ((buffer[ptr + 3]) & 0xff) << (24 - endbit);
					if (bits > 32 && endbit != 0) {
						ret |= ((buffer[ptr + 4]) & 0xff) << (32 - endbit);
					}
				}
			}
		}
		return (m & ret);
	}

	public int look1() {
		if (endbyte >= storage)
			return (-1);
		return ((buffer[ptr] >> endbit) & 1);
	}

	public void adv(int bits) {
		bits += endbit;
		ptr += bits / 8;
		endbyte += bits / 8;
		endbit = bits & 7;
	}

	public void adv1() {
		++endbit;
		if (endbit > 7) {
			endbit = 0;
			ptr++;
			endbyte++;
		}
	}

	public int read(int bits) {
		int ret;
		int m = mask[bits];

		bits += endbit;

		if (endbyte + 4 >= storage) {
			ret = -1;
			if (endbyte + (bits - 1) / 8 >= storage) {
				ptr += bits / 8;
				endbyte += bits / 8;
				endbit = bits & 7;
				return (ret);
			}
		}

		ret = ((buffer[ptr]) & 0xff) >>> endbit;
		if (bits > 8) {
			ret |= ((buffer[ptr + 1]) & 0xff) << (8 - endbit);
			if (bits > 16) {
				ret |= ((buffer[ptr + 2]) & 0xff) << (16 - endbit);
				if (bits > 24) {
					ret |= ((buffer[ptr + 3]) & 0xff) << (24 - endbit);
					if (bits > 32 && endbit != 0) {
						ret |= ((buffer[ptr + 4]) & 0xff) << (32 - endbit);
					}
				}
			}
		}

		ret &= m;

		ptr += bits / 8;
		endbyte += bits / 8;
		endbit = bits & 7;
		return (ret);
	}

	public int readB(int bits) {
		int ret;
		int m = 32 - bits;

		bits += endbit;

		if (endbyte + 4 >= storage) {
			/* not the main path */
			ret = -1;
			if (endbyte * 8 + bits > storage * 8) {
				ptr += bits / 8;
				endbyte += bits / 8;
				endbit = bits & 7;
				return (ret);
			}
		}

		ret = (buffer[ptr] & 0xff) << (24 + endbit);
		if (bits > 8) {
			ret |= (buffer[ptr + 1] & 0xff) << (16 + endbit);
			if (bits > 16) {
				ret |= (buffer[ptr + 2] & 0xff) << (8 + endbit);
				if (bits > 24) {
					ret |= (buffer[ptr + 3] & 0xff) << (endbit);
					if (bits > 32 && (endbit != 0))
						ret |= (buffer[ptr + 4] & 0xff) >> (8 - endbit);
				}
			}
		}
		ret = (ret >>> (m >> 1)) >>> ((m + 1) >> 1);

		ptr += bits / 8;
		endbyte += bits / 8;
		endbit = bits & 7;
		return (ret);
	}

	public int read1() {
		int ret;
		if (endbyte >= storage) {
			ret = -1;
			endbit++;
			if (endbit > 7) {
				endbit = 0;
				ptr++;
				endbyte++;
			}
			return (ret);
		}

		ret = (buffer[ptr] >> endbit) & 1;

		endbit++;
		if (endbit > 7) {
			endbit = 0;
			ptr++;
			endbyte++;
		}
		return (ret);
	}

	public int bytes() {
		return (endbyte + (endbit + 7) / 8);
	}

	public int bits() {
		return (endbyte * 8 + endbit);
	}

	public byte[] buffer() {
		return (buffer);
	}

	public static int ilog(int v) {
		int ret = 0;
		while (v > 0) {
			ret++;
			v >>>= 1;
		}
		return (ret);
	}

	public static void report(String in) {
		System.err.println(in);
		System.exit(1);
	}
}
