1/*
2 * Copyright (C) 2011 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1.  Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions and the following disclaimer.
10 * 2.  Redistributions in binary form must reproduce the above copyright
11 *     notice, this list of conditions and the following disclaimer in the
12 *     documentation and/or other materials provided with the distribution.
13 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 *     its contributors may be used to endorse or promote products derived
15 *     from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#ifndef ZeroPole_h
30#define ZeroPole_h
31
32#include "platform/PlatformExport.h"
33
34namespace blink {
35
36// ZeroPole is a simple filter with one zero and one pole.
37
38class PLATFORM_EXPORT ZeroPole {
39public:
40    ZeroPole()
41        : m_zero(0)
42        , m_pole(0)
43        , m_lastX(0)
44        , m_lastY(0)
45    {
46    }
47
48    void process(const float *source, float *destination, unsigned framesToProcess);
49
50    // Reset filter state.
51    void reset() { m_lastX = 0; m_lastY = 0; }
52
53    void setZero(float zero) { m_zero = zero; }
54    void setPole(float pole) { m_pole = pole; }
55
56    float zero() const { return m_zero; }
57    float pole() const { return m_pole; }
58
59private:
60    float m_zero;
61    float m_pole;
62    float m_lastX;
63    float m_lastY;
64};
65
66} // namespace blink
67
68#endif // ZeroPole_h
69