1 /*
2  * Copyrightm (C) 2010 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef __ECHO_SUPPRESSOR_H__
18 #define __ECHO_SUPPRESSOR_H__
19 
20 #include <stdint.h>
21 
22 class EchoSuppressor
23 {
24 public:
25     // The sampleCount must be power of 2.
26     EchoSuppressor(int sampleCount, int tailLength);
27     ~EchoSuppressor();
28     void run(int16_t *playbacked, int16_t *recorded);
29 
30 private:
31     int mShift;
32     int mScale;
33     int mSampleCount;
34     int mWindowSize;
35     int mTailLength;
36     int mRecordLength;
37     int mRecordOffset;
38 
39     uint16_t *mXs;
40     uint32_t *mXSums;
41     uint32_t *mX2Sums;
42     uint16_t *mXRecords;
43 
44     uint32_t mYSum;
45     uint32_t mY2Sum;
46     uint32_t *mYRecords;
47     uint32_t *mY2Records;
48 
49     uint32_t *mXYSums;
50     uint32_t *mXYRecords;
51 
52     int32_t mLastX;
53     int32_t mLastY;
54 
55     float mWeight;
56 };
57 
58 #endif
59