/*

 * Copyright (c) 2007, 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.

 *

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package com.sun.media.sound;

/**

 * A resampler that uses first-order (linear) interpolation.

 *

 * This one doesn't perform float to int casting inside the processing loop.

 *

 * @author Karl Helgason

 */

public class SoftLinearResampler2 extends SoftAbstractResampler {

    public int getPadding() {

        return 2;

    }

    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;

        // Check if we have do anything

        if (!(ix < ix_end && ox < ox_end))

            return;

        // 15 bit shift was choosed because

        // it resulted in no drift between p_ix and ix.

        int p_ix = (int) (ix * (1 << 15));

        int p_ix_end = (int) (ix_end * (1 << 15));

        int p_pitch = (int) (pitch * (1 << 15));

        // Pitch needs to recalculated

        // to ensure no drift between p_ix and ix.

        pitch = p_pitch * (1f / (1 << 15));

        if (pitchstep == 0f) {

            // To reduce

            //    while (p_ix < p_ix_end && ox < ox_end)

            // into

            //    while  (ox < ox_end)

            // We need to calculate new ox_end value.

            int p_ix_len = p_ix_end - p_ix;

            int p_mod = p_ix_len % p_pitch;

            if (p_mod != 0)

                p_ix_len += p_pitch - p_mod;

            int ox_end2 = ox + p_ix_len / p_pitch;

            if (ox_end2 < ox_end)

                ox_end = ox_end2;

            while (ox < ox_end) {

                int iix = p_ix >> 15;

                float fix = ix - iix;

                float i = in[iix];

                out[ox++] = i + (in[iix + 1] - i) * fix;

                p_ix += p_pitch;

                ix += pitch;

            }

        } else {

            int p_pitchstep = (int) (pitchstep * (1 << 15));

            pitchstep = p_pitchstep * (1f / (1 << 15));

            while (p_ix < p_ix_end && ox < ox_end) {

                int iix = p_ix >> 15;

                float fix = ix - iix;

                float i = in[iix];

                out[ox++] = i + (in[iix + 1] - i) * fix;

                ix += pitch;

                p_ix += p_pitch;

                pitch += pitchstep;

                p_pitch += p_pitchstep;

            }

        }

        in_offset[0] = ix;

        out_offset[0] = ox;

        startpitch[0] = pitch;

    }

}