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/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef RDSP_H
#define RDSP_H
#include <complex>
#include <log/log.h>
#include <vector>
#include <map>
using FloatVec = std::vector<float>;
using IntVec = std::vector<int>;
using ComplexVec = std::vector<std::complex<float>>;
// =======
// Helper Functions
// =======
template <class T>
static T dBtoLinear(T valueDb) {
return pow (10, valueDb / 20.0);
}
template <class T>
static T linearToDb(T value) {
return 20 * log10(value);
}
// =======
// DSP window creation
// =======
#define TWOPI (M_PI * 2)
enum rdsp_window_type {
RDSP_WINDOW_RECTANGULAR,
RDSP_WINDOW_TRIANGULAR,
RDSP_WINDOW_TRIANGULAR_FLAT_TOP,
RDSP_WINDOW_HAMMING,
RDSP_WINDOW_HAMMING_FLAT_TOP,
RDSP_WINDOW_HANNING,
RDSP_WINDOW_HANNING_FLAT_TOP,
};
template <typename T>
static void fillRectangular(T &v) {
const size_t size = v.size();
for (size_t i = 0; i < size; i++) {
v[i] = 1.0;
}
} //rectangular
template <typename T>
static void fillTriangular(T &v, size_t overlap) {
const size_t size = v.size();
//ramp up
size_t i = 0;
if (overlap > 0) {
for (; i < overlap; i++) {
v[i] = (2.0 * i + 1) / (2 * overlap);
}
}
//flat top
for (; i < size - overlap; i++) {
v[i] = 1.0;
}
//ramp down
if (overlap > 0) {
for (; i < size; i++) {
v[i] = (2.0 * (size - i) - 1) / (2 * overlap);
}
}
} //triangular
template <typename T>
static void fillHamming(T &v, size_t overlap) {
const size_t size = v.size();
const size_t twoOverlap = 2 * overlap;
size_t i = 0;
if (overlap > 0) {
for (; i < overlap; i++) {
v[i] = 0.54 - 0.46 * cos(TWOPI * i /(twoOverlap - 1));
}
}
//flat top
for (; i < size - overlap; i++) {
v[i] = 1.0;
}
//ramp down
if (overlap > 0) {
for (; i < size; i++) {
int k = i - ((int)size - 2 * overlap);
v[i] = 0.54 - 0.46 * cos(TWOPI * k / (twoOverlap - 1));
}
}
} //hamming
template <typename T>
static void fillHanning(T &v, size_t overlap) {
const size_t size = v.size();
const size_t twoOverlap = 2 * overlap;
//ramp up
size_t i = 0;
if (overlap > 0) {
for (; i < overlap; i++) {
v[i] = 0.5 * (1.0 - cos(TWOPI * i / (twoOverlap - 1)));
}
}
//flat top
for (; i < size - overlap; i++) {
v[i] = 1.0;
}
//ramp down
if (overlap > 0) {
for (; i < size; i++) {
int k = i - ((int)size - 2 * overlap);
v[i] = 0.5 * (1.0 - cos(TWOPI * k / (twoOverlap - 1)));
}
}
}
template <typename T>
static void fill_window(T &v, int type, size_t size, size_t overlap) {
if (overlap > size / 2) {
overlap = size / 2;
}
v.resize(size);
switch (type) {
case RDSP_WINDOW_RECTANGULAR:
fillRectangular(v);
break;
case RDSP_WINDOW_TRIANGULAR:
fillTriangular(v, size / 2);
break;
case RDSP_WINDOW_TRIANGULAR_FLAT_TOP:
fillTriangular(v, overlap);
break;
case RDSP_WINDOW_HAMMING:
fillHamming(v, size / 2);
break;
case RDSP_WINDOW_HAMMING_FLAT_TOP:
fillHamming(v, overlap);
break;
case RDSP_WINDOW_HANNING:
fillHanning(v, size / 2);
break;
case RDSP_WINDOW_HANNING_FLAT_TOP:
fillHanning(v, overlap);
break;
default:
ALOGE("Error: unknown window type %d", type);
}
}
//};
#endif //RDSP_H
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