/* -*-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.jorbis;

import com.jcraft.jogg.*;

class Floor0 extends FuncFloor {

	void pack(Object i, Buffer opb) {
		InfoFloor0 info = (InfoFloor0) i;
		opb.write(info.order, 8);
		opb.write(info.rate, 16);
		opb.write(info.barkmap, 16);
		opb.write(info.ampbits, 6);
		opb.write(info.ampdB, 8);
		opb.write(info.numbooks - 1, 4);
		for (int j = 0; j < info.numbooks; j++)
			opb.write(info.books[j], 8);
	}

	Object unpack(Info vi, Buffer opb) {
		InfoFloor0 info = new InfoFloor0();
		info.order = opb.read(8);
		info.rate = opb.read(16);
		info.barkmap = opb.read(16);
		info.ampbits = opb.read(6);
		info.ampdB = opb.read(8);
		info.numbooks = opb.read(4) + 1;

		if ((info.order < 1) || (info.rate < 1) || (info.barkmap < 1)
				|| (info.numbooks < 1)) {
			return (null);
		}

		for (int j = 0; j < info.numbooks; j++) {
			info.books[j] = opb.read(8);
			if (info.books[j] < 0 || info.books[j] >= vi.books) {
				return (null);
			}
		}
		return (info);
	}

	Object look(DspState vd, InfoMode mi, Object i) {
		float scale;
		Info vi = vd.vi;
		InfoFloor0 info = (InfoFloor0) i;
		LookFloor0 look = new LookFloor0();
		look.m = info.order;
		look.n = vi.blocksizes[mi.blockflag] / 2;
		look.ln = info.barkmap;
		look.vi = info;
		look.lpclook.init(look.ln, look.m);

		// we choose a scaling constant so that:
		scale = look.ln / toBARK((float) (info.rate / 2.));

		// the mapping from a linear scale to a smaller bark scale is
		// straightforward. We do *not* make sure that the linear mapping
		// does not skip bark-scale bins; the decoder simply skips them and
		// the encoder may do what it wishes in filling them. They're
		// necessary in some mapping combinations to keep the scale spacing
		// accurate
		look.linearmap = new int[look.n];
		for (int j = 0; j < look.n; j++) {
			int val = (int) Math.floor(toBARK((float) ((info.rate / 2.)
					/ look.n * j))
					* scale); // bark numbers represent band edges
			if (val >= look.ln)
				val = look.ln; // guard against the approximation
			look.linearmap[j] = val;
		}
		return look;
	}

	static float toBARK(float f) {
		return (float) (13.1 * Math.atan(.00074 * (f)) + 2.24
				* Math.atan((f) * (f) * 1.85e-8) + 1e-4 * (f));
	}

	Object state(Object i) {
		EchstateFloor0 state = new EchstateFloor0();
		InfoFloor0 info = (InfoFloor0) i;

		// a safe size if usually too big (dim==1)
		state.codewords = new int[info.order];
		state.curve = new float[info.barkmap];
		state.frameno = -1;
		return (state);
	}

	void free_info(Object i) {
	}

	void free_look(Object i) {
	}

	void free_state(Object vs) {
	}

	int forward(Block vb, Object i, float[] in, float[] out, Object vs) {
		return 0;
	}

	float[] lsp = null;

	int inverse(Block vb, Object i, float[] out) {
		// System.err.println("Floor0.inverse "+i.getClass()+"]");
		LookFloor0 look = (LookFloor0) i;
		InfoFloor0 info = look.vi;
		int ampraw = vb.opb.read(info.ampbits);
		if (ampraw > 0) { // also handles the -1 out of data case
			int maxval = (1 << info.ampbits) - 1;
			float amp = (float) ampraw / maxval * info.ampdB;
			int booknum = vb.opb.read(Util.ilog(info.numbooks));

			if (booknum != -1 && booknum < info.numbooks) {

				synchronized (this) {
					if (lsp == null || lsp.length < look.m) {
						lsp = new float[look.m];
					} else {
						for (int j = 0; j < look.m; j++)
							lsp[j] = 0.f;
					}

					CodeBook b = vb.vd.fullbooks[info.books[booknum]];
					float last = 0.f;

					for (int j = 0; j < look.m; j++)
						out[j] = 0.0f;

					for (int j = 0; j < look.m; j += b.dim) {
						if (b.decodevs(lsp, j, vb.opb, 1, -1) == -1) {
							for (int k = 0; k < look.n; k++)
								out[k] = 0.0f;
							return (0);
						}
					}
					for (int j = 0; j < look.m;) {
						for (int k = 0; k < b.dim; k++, j++)
							lsp[j] += last;
						last = lsp[j - 1];
					}
					// take the coefficients back to a spectral envelope curve
					Lsp.lsp_to_curve(out, look.linearmap, look.n, look.ln, lsp,
							look.m, amp, info.ampdB);

					return (1);
				}
			}
		}
		return (0);
	}

	Object inverse1(Block vb, Object i, Object memo) {
		LookFloor0 look = (LookFloor0) i;
		InfoFloor0 info = look.vi;
		float[] lsp = null;
		if (memo instanceof float[]) {
			lsp = (float[]) memo;
		}

		int ampraw = vb.opb.read(info.ampbits);
		if (ampraw > 0) { // also handles the -1 out of data case
			int maxval = (1 << info.ampbits) - 1;
			float amp = (float) ampraw / maxval * info.ampdB;
			int booknum = vb.opb.read(Util.ilog(info.numbooks));

			if (booknum != -1 && booknum < info.numbooks) {
				CodeBook b = vb.vd.fullbooks[info.books[booknum]];
				float last = 0.f;

				if (lsp == null || lsp.length < look.m + 1) {
					lsp = new float[look.m + 1];
				} else {
					for (int j = 0; j < lsp.length; j++)
						lsp[j] = 0.f;
				}

				for (int j = 0; j < look.m; j += b.dim) {
					if (b.decodev_set(lsp, j, vb.opb, b.dim) == -1) {
						return (null);
					}
				}

				for (int j = 0; j < look.m;) {
					for (int k = 0; k < b.dim; k++, j++)
						lsp[j] += last;
					last = lsp[j - 1];
				}
				lsp[look.m] = amp;
				return (lsp);
			}
		}
		return (null);
	}

	int inverse2(Block vb, Object i, Object memo, float[] out) {
		LookFloor0 look = (LookFloor0) i;
		InfoFloor0 info = look.vi;

		if (memo != null) {
			float[] lsp = (float[]) memo;
			float amp = lsp[look.m];

			Lsp.lsp_to_curve(out, look.linearmap, look.n, look.ln, lsp, look.m,
					amp, info.ampdB);
			return (1);
		}
		for (int j = 0; j < look.n; j++) {
			out[j] = 0.f;
		}
		return (0);
	}

	static float fromdB(float x) {
		return (float) (Math.exp((x) * .11512925));
	}

	static void lsp_to_lpc(float[] lsp, float[] lpc, int m) {
		int i, j, m2 = m / 2;
		float[] O = new float[m2];
		float[] E = new float[m2];
		float A;
		float[] Ae = new float[m2 + 1];
		float[] Ao = new float[m2 + 1];
		float B;
		float[] Be = new float[m2];
		float[] Bo = new float[m2];
		float temp;

		// even/odd roots setup
		for (i = 0; i < m2; i++) {
			O[i] = (float) (-2. * Math.cos(lsp[i * 2]));
			E[i] = (float) (-2. * Math.cos(lsp[i * 2 + 1]));
		}

		// set up impulse response
		for (j = 0; j < m2; j++) {
			Ae[j] = 0.f;
			Ao[j] = 1.f;
			Be[j] = 0.f;
			Bo[j] = 1.f;
		}
		Ao[j] = 1.f;
		Ae[j] = 1.f;

		// run impulse response
		for (i = 1; i < m + 1; i++) {
			A = B = 0.f;
			for (j = 0; j < m2; j++) {
				temp = O[j] * Ao[j] + Ae[j];
				Ae[j] = Ao[j];
				Ao[j] = A;
				A += temp;

				temp = E[j] * Bo[j] + Be[j];
				Be[j] = Bo[j];
				Bo[j] = B;
				B += temp;
			}
			lpc[i - 1] = (A + Ao[j] + B - Ae[j]) / 2;
			Ao[j] = A;
			Ae[j] = B;
		}
	}

	static void lpc_to_curve(float[] curve, float[] lpc, float amp,
			LookFloor0 l, String name, int frameno) {
		// l->m+1 must be less than l->ln, but guard in case we get a bad stream
		float[] lcurve = new float[Math.max(l.ln * 2, l.m * 2 + 2)];

		if (amp == 0) {
			for (int j = 0; j < l.n; j++)
				curve[j] = 0.0f;
			return;
		}
		l.lpclook.lpc_to_curve(lcurve, lpc, amp);

		for (int i = 0; i < l.n; i++)
			curve[i] = lcurve[l.linearmap[i]];
	}

	class InfoFloor0 {
		int order;
		int rate;
		int barkmap;

		int ampbits;
		int ampdB;

		int numbooks; // <= 16
		int[] books = new int[16];
	}

	class LookFloor0 {
		int n;
		int ln;
		int m;
		int[] linearmap;

		InfoFloor0 vi;
		Lpc lpclook = new Lpc();
	}

	class EchstateFloor0 {
		int[] codewords;
		float[] curve;
		long frameno;
		long codes;
	}
}
