1/* //device/servers/AudioFlinger/AudioCoefInterpolator.cpp
2 **
3 ** Copyright 2008, The Android Open Source Project
4 **
5 ** Licensed under the Apache License, Version 2.0 (the "License");
6 ** you may not use this file except in compliance with the License.
7 ** You may obtain a copy of the License at
8 **
9 **     http://www.apache.org/licenses/LICENSE-2.0
10 **
11 ** Unless required by applicable law or agreed to in writing, software
12 ** distributed under the License is distributed on an "AS IS" BASIS,
13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 ** See the License for the specific language governing permissions and
15 ** limitations under the License.
16 */
17
18#include <string.h>
19
20#include <cutils/compiler.h>
21
22#include "AudioCoefInterpolator.h"
23
24namespace android {
25
26AudioCoefInterpolator::AudioCoefInterpolator(size_t nInDims,
27                                             const size_t inDims[],
28                                             size_t nOutDims,
29                                             const audio_coef_t * table) {
30    mNumInDims = nInDims;
31    memcpy(mInDims, inDims, nInDims * sizeof(size_t));
32    mNumOutDims = nOutDims;
33    mTable = table;
34    // Initialize offsets array
35    size_t dim = nInDims - 1;
36    mInDimOffsets[nInDims - 1] = nOutDims;
37    while (dim-- > 0) {
38        mInDimOffsets[dim] = mInDimOffsets[dim + 1] * mInDims[dim + 1];
39    }
40}
41
42void AudioCoefInterpolator::getCoef(const int intCoord[], uint32_t fracCoord[],
43                                    audio_coef_t out[]) {
44    size_t index = 0;
45    size_t dim = mNumInDims;
46    while (dim-- > 0) {
47        if (CC_UNLIKELY(intCoord[dim] < 0)) {
48            fracCoord[dim] = 0;
49        } else if (CC_UNLIKELY(intCoord[dim] >= (int)mInDims[dim] - 1)) {
50            fracCoord[dim] = 0;
51            index += mInDimOffsets[dim] * (mInDims[dim] - 1);
52        } else {
53            index += mInDimOffsets[dim] * intCoord[dim];
54        }
55    }
56    getCoefRecurse(index, fracCoord, out, 0);
57}
58
59void AudioCoefInterpolator::getCoefRecurse(size_t index,
60                                           const uint32_t fracCoord[],
61                                           audio_coef_t out[], size_t dim) {
62    if (dim == mNumInDims) {
63        memcpy(out, mTable + index, mNumOutDims * sizeof(audio_coef_t));
64    } else {
65        getCoefRecurse(index, fracCoord, out, dim + 1);
66        if (CC_LIKELY(fracCoord != 0)) {
67           audio_coef_t tempCoef[MAX_OUT_DIMS];
68           getCoefRecurse(index + mInDimOffsets[dim], fracCoord, tempCoef,
69                           dim + 1);
70            size_t d = mNumOutDims;
71            while (d-- > 0) {
72                out[d] = interp(out[d], tempCoef[d], fracCoord[dim]);
73            }
74        }
75    }
76}
77
78audio_coef_t AudioCoefInterpolator::interp(audio_coef_t lo, audio_coef_t hi,
79                                           uint32_t frac) {
80    int64_t delta = static_cast<int64_t>(hi-lo) * frac;
81    return lo + static_cast<audio_coef_t> (delta >> 32);
82}
83
84}
85