/*
 * Copyright 2007 Sun Microsystems, Inc.  All Rights Reserved.
 * 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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * 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.
 */

package com.sun.media.sound;

/**
 * 
 * A resampler that uses third-order (cubic) interpolation.
 * 
 * @version %I%, %E%
 * @author Karl Helgason
 */
public class SoftCubicResampler extends SoftAbstractResampler {

	public int getPadding() {
		return 3;
	}

	public void interpolate(float[] in, float[] in_offset, float in_end,
			float[] startpitch, float pitchstep, float[] out, int[] out_offset,
			int out_end) {
		float pitch = startpitch[0];
		float ix = in_offset[0];
		int ox = out_offset[0];
		float ix_end = in_end;
		int ox_end = out_end;
		if (pitchstep == 0) {
			while (ix < ix_end && ox < ox_end) {
				int iix = (int) ix;
				float fix = ix - iix;
				float y0 = in[iix - 1];
				float y1 = in[iix];
				float y2 = in[iix + 1];
				float y3 = in[iix + 2];
				float a0 = y3 - y2 + y1 - y0;
				float a1 = y0 - y1 - a0;
				float a2 = y2 - y0;
				float a3 = y1;				
				//float fix2 = fix * fix;
				//out[ox++] = (a0 * fix + a1) * fix2 + (a2 * fix + a3);
				out[ox++] = ((a0 * fix + a1) * fix + a2) * fix + a3;
				ix += pitch;
			}
		} else {
			while (ix < ix_end && ox < ox_end) {
				int iix = (int) ix;
				float fix = ix - iix;
				float y0 = in[iix - 1];
				float y1 = in[iix];
				float y2 = in[iix + 1];
				float y3 = in[iix + 2];
				float a0 = y3 - y2 + y1 - y0;
				float a1 = y0 - y1 - a0;
				float a2 = y2 - y0;
				float a3 = y1;
				//float fix2 = fix * fix;
				//out[ox++] = (a0 * fix + a1) * fix2 + (a2 * fix + a3);
				out[ox++] = ((a0 * fix + a1) * fix + a2) * fix + a3;
				ix += pitch;
				pitch += pitchstep;
			}
		}
		in_offset[0] = ix;
		out_offset[0] = ox;
		startpitch[0] = pitch;

	}

}