1/*
2 * Copyright (C) 2010 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// Mac OS X - specific FFTFrame implementation
30
31#include "config.h"
32
33#if ENABLE(WEB_AUDIO)
34
35#include "FFTFrame.h"
36
37namespace WebCore {
38
39const int kMaxFFTPow2Size = 24;
40
41FFTSetup* FFTFrame::fftSetups = 0;
42
43// Normal constructor: allocates for a given fftSize
44FFTFrame::FFTFrame(unsigned fftSize)
45    : m_realData(fftSize)
46    , m_imagData(fftSize)
47{
48    m_FFTSize = fftSize;
49    m_log2FFTSize = static_cast<unsigned>(log2(fftSize));
50
51    // We only allow power of two
52    ASSERT(1UL << m_log2FFTSize == m_FFTSize);
53
54    // Lazily create and share fftSetup with other frames
55    m_FFTSetup = fftSetupForSize(fftSize);
56
57    // Setup frame data
58    m_frame.realp = m_realData.data();
59    m_frame.imagp = m_imagData.data();
60}
61
62// Creates a blank/empty frame (interpolate() must later be called)
63FFTFrame::FFTFrame()
64    : m_realData(0)
65    , m_imagData(0)
66{
67    // Later will be set to correct values when interpolate() is called
68    m_frame.realp = 0;
69    m_frame.imagp = 0;
70
71    m_FFTSize = 0;
72    m_log2FFTSize = 0;
73}
74
75// Copy constructor
76FFTFrame::FFTFrame(const FFTFrame& frame)
77    : m_FFTSize(frame.m_FFTSize)
78    , m_log2FFTSize(frame.m_log2FFTSize)
79    , m_FFTSetup(frame.m_FFTSetup)
80    , m_realData(frame.m_FFTSize)
81    , m_imagData(frame.m_FFTSize)
82{
83    // Setup frame data
84    m_frame.realp = m_realData.data();
85    m_frame.imagp = m_imagData.data();
86
87    // Copy/setup frame data
88    unsigned nbytes = sizeof(float) * m_FFTSize;
89    memcpy(realData(), frame.m_frame.realp, nbytes);
90    memcpy(imagData(), frame.m_frame.imagp, nbytes);
91}
92
93FFTFrame::~FFTFrame()
94{
95}
96
97void FFTFrame::multiply(const FFTFrame& frame)
98{
99    FFTFrame& frame1 = *this;
100    const FFTFrame& frame2 = frame;
101
102    float* realP1 = frame1.realData();
103    float* imagP1 = frame1.imagData();
104    const float* realP2 = frame2.realData();
105    const float* imagP2 = frame2.imagData();
106
107    // Scale accounts for vecLib's peculiar scaling
108    // This ensures the right scaling all the way back to inverse FFT
109    float scale = 0.5f;
110
111    // Multiply packed DC/nyquist component
112    realP1[0] *= scale * realP2[0];
113    imagP1[0] *= scale * imagP2[0];
114
115    // Multiply the rest, skipping packed DC/Nyquist components
116    DSPSplitComplex sc1 = frame1.dspSplitComplex();
117    sc1.realp++;
118    sc1.imagp++;
119
120    DSPSplitComplex sc2 = frame2.dspSplitComplex();
121    sc2.realp++;
122    sc2.imagp++;
123
124    unsigned halfSize = m_FFTSize / 2;
125
126    // Complex multiply
127    vDSP_zvmul(&sc1, 1, &sc2, 1, &sc1, 1, halfSize - 1, 1 /* normal multiplication */);
128
129    // We've previously scaled the packed part, now scale the rest.....
130    vDSP_vsmul(sc1.realp, 1, &scale, sc1.realp, 1, halfSize - 1);
131    vDSP_vsmul(sc1.imagp, 1, &scale, sc1.imagp, 1, halfSize - 1);
132}
133
134void FFTFrame::doFFT(float* data)
135{
136    vDSP_ctoz((DSPComplex*)data, 2, &m_frame, 1, m_FFTSize / 2);
137    vDSP_fft_zrip(m_FFTSetup, &m_frame, 1, m_log2FFTSize, FFT_FORWARD);
138}
139
140void FFTFrame::doInverseFFT(float* data)
141{
142    vDSP_fft_zrip(m_FFTSetup, &m_frame, 1, m_log2FFTSize, FFT_INVERSE);
143    vDSP_ztoc(&m_frame, 1, (DSPComplex*)data, 2, m_FFTSize / 2);
144
145    // Do final scaling so that x == IFFT(FFT(x))
146    float scale = 0.5f / m_FFTSize;
147    vDSP_vsmul(data, 1, &scale, data, 1, m_FFTSize);
148}
149
150FFTSetup FFTFrame::fftSetupForSize(unsigned fftSize)
151{
152    if (!fftSetups) {
153        fftSetups = (FFTSetup*)malloc(sizeof(FFTSetup) * kMaxFFTPow2Size);
154        memset(fftSetups, 0, sizeof(FFTSetup) * kMaxFFTPow2Size);
155    }
156
157    int pow2size = static_cast<int>(log2(fftSize));
158    ASSERT(pow2size < kMaxFFTPow2Size);
159    if (!fftSetups[pow2size])
160        fftSetups[pow2size] = vDSP_create_fftsetup(pow2size, FFT_RADIX2);
161
162    return fftSetups[pow2size];
163}
164
165void FFTFrame::initialize()
166{
167}
168
169void FFTFrame::cleanup()
170{
171    if (!fftSetups)
172        return;
173
174    for (int i = 0; i < kMaxFFTPow2Size; ++i) {
175        if (fftSetups[i])
176            vDSP_destroy_fftsetup(fftSetups[i]);
177    }
178
179    free(fftSetups);
180    fftSetups = 0;
181}
182
183float* FFTFrame::realData() const
184{
185    return m_frame.realp;
186}
187
188float* FFTFrame::imagData() const
189{
190    return m_frame.imagp;
191}
192
193} // namespace WebCore
194
195#endif // ENABLE(WEB_AUDIO)
196