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      1 /*
      2  * Copyright (C) 2016 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 TIME_H_
     18 
     19 #define TIME_H_
     20 
     21 #include <stdio.h>
     22 #include <stdint.h>
     23 #include <stdbool.h>
     24 
     25 #ifdef __cplusplus
     26 extern "C" {
     27 #endif
     28 
     29 #define NUM_TIME_SYNC_DATAPOINTS    16
     30 
     31 typedef struct {
     32     uint64_t time1[NUM_TIME_SYNC_DATAPOINTS];
     33     uint64_t time2[NUM_TIME_SYNC_DATAPOINTS];
     34     size_t n;
     35     size_t i;
     36 
     37     uint64_t time1_base;
     38     uint64_t time2_base;
     39 
     40     bool estimate_valid;
     41     float alpha, beta;
     42 
     43     uint8_t hold_count;
     44 
     45 } time_sync_t;
     46 
     47 void time_sync_reset(time_sync_t *sync);
     48 bool time_sync_init(time_sync_t *sync);
     49 void time_sync_truncate(time_sync_t *sync, size_t window_size);
     50 bool time_sync_add(time_sync_t *sync, uint64_t time1, uint64_t time2);
     51 bool time_sync_estimate_time1(time_sync_t *sync, uint64_t time2, uint64_t *time1);
     52 void time_sync_hold(time_sync_t *sync, uint8_t count);
     53 
     54 #ifdef __cplusplus
     55 }
     56 #endif
     57 
     58 #endif  // TIME_H_
     59