/*

 * Copyright (c) 2007, 2013, Oracle and/or its affiliates. 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package com.sun.media.sound;

/**

 * A resampler that uses third-order (cubic) interpolation.

 *

 * @author Karl Helgason

 */

public final 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;

    }

}