1 /*
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7  * published by the Free Software Foundation.  Oracle designates this
8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle in the LICENSE file that accompanied this code.
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11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
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17  * You should have received a copy of the GNU General Public License version
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19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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25 
26 package com.sun.media.sound;
27 
28 /**
29  * A resampler that uses third-order (cubic) interpolation.
30  *
31  * @author Karl Helgason
32  */
33 public final class SoftCubicResampler extends SoftAbstractResampler {
34 
35     @Override
getPadding()36     public int getPadding() {
37         return 3;
38     }
39 
40     @Override
interpolate(float[] in, float[] in_offset, float in_end, float[] startpitch, float pitchstep, float[] out, int[] out_offset, int out_end)41     public void interpolate(float[] in, float[] in_offset, float in_end,
42                             float[] startpitch, float pitchstep, float[] out, int[] out_offset,
43                             int out_end) {
44         float pitch = startpitch[0];
45         float ix = in_offset[0];
46         int ox = out_offset[0];
47         float ix_end = in_end;
48         int ox_end = out_end;
49         if (pitchstep == 0) {
50             while (ix < ix_end && ox < ox_end) {
51                 int iix = (int) ix;
52                 float fix = ix - iix;
53                 float y0 = in[iix - 1];
54                 float y1 = in[iix];
55                 float y2 = in[iix + 1];
56                 float y3 = in[iix + 2];
57                 float a0 = y3 - y2 + y1 - y0;
58                 float a1 = y0 - y1 - a0;
59                 float a2 = y2 - y0;
60                 float a3 = y1;
61                 //float fix2 = fix * fix;
62                 //out[ox++] = (a0 * fix + a1) * fix2 + (a2 * fix + a3);
63                 out[ox++] = ((a0 * fix + a1) * fix + a2) * fix + a3;
64                 ix += pitch;
65             }
66         } else {
67             while (ix < ix_end && ox < ox_end) {
68                 int iix = (int) ix;
69                 float fix = ix - iix;
70                 float y0 = in[iix - 1];
71                 float y1 = in[iix];
72                 float y2 = in[iix + 1];
73                 float y3 = in[iix + 2];
74                 float a0 = y3 - y2 + y1 - y0;
75                 float a1 = y0 - y1 - a0;
76                 float a2 = y2 - y0;
77                 float a3 = y1;
78                 //float fix2 = fix * fix;
79                 //out[ox++] = (a0 * fix + a1) * fix2 + (a2 * fix + a3);
80                 out[ox++] = ((a0 * fix + a1) * fix + a2) * fix + a3;
81                 ix += pitch;
82                 pitch += pitchstep;
83             }
84         }
85         in_offset[0] = ix;
86         out_offset[0] = ox;
87         startpitch[0] = pitch;
88 
89     }
90 }
91