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      1 /*
      2  * Copyright (C) 2012 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 #define __STDC_LIMIT_MACROS
     18 
     19 #define LOG_TAG "common_time"
     20 #include <utils/Log.h>
     21 
     22 #include <stdint.h>
     23 
     24 #include <utils/Errors.h>
     25 #include <utils/LinearTransform.h>
     26 
     27 #include "common_clock.h"
     28 
     29 namespace android {
     30 
     31 CommonClock::CommonClock() {
     32     cur_slew_        = 0;
     33     cur_trans_valid_ = false;
     34 
     35     cur_trans_.a_zero = 0;
     36     cur_trans_.b_zero = 0;
     37     cur_trans_.a_to_b_numer = local_to_common_freq_numer_ = 1;
     38     cur_trans_.a_to_b_denom = local_to_common_freq_denom_ = 1;
     39     duration_trans_ = cur_trans_;
     40 }
     41 
     42 bool CommonClock::init(uint64_t local_freq) {
     43     Mutex::Autolock lock(&lock_);
     44 
     45     if (!local_freq)
     46         return false;
     47 
     48     uint64_t numer = kCommonFreq;
     49     uint64_t denom = local_freq;
     50 
     51     LinearTransform::reduce(&numer, &denom);
     52     if ((numer > UINT32_MAX) || (denom > UINT32_MAX)) {
     53         ALOGE("Overflow in CommonClock::init while trying to reduce %lld/%lld",
     54              kCommonFreq, local_freq);
     55         return false;
     56     }
     57 
     58     cur_trans_.a_to_b_numer = local_to_common_freq_numer_ =
     59         static_cast<uint32_t>(numer);
     60     cur_trans_.a_to_b_denom = local_to_common_freq_denom_ =
     61         static_cast<uint32_t>(denom);
     62     duration_trans_ = cur_trans_;
     63 
     64     return true;
     65 }
     66 
     67 status_t CommonClock::localToCommon(int64_t local, int64_t *common_out) const {
     68     Mutex::Autolock lock(&lock_);
     69 
     70     if (!cur_trans_valid_)
     71         return INVALID_OPERATION;
     72 
     73     if (!cur_trans_.doForwardTransform(local, common_out))
     74         return INVALID_OPERATION;
     75 
     76     return OK;
     77 }
     78 
     79 status_t CommonClock::commonToLocal(int64_t common, int64_t *local_out) const {
     80     Mutex::Autolock lock(&lock_);
     81 
     82     if (!cur_trans_valid_)
     83         return INVALID_OPERATION;
     84 
     85     if (!cur_trans_.doReverseTransform(common, local_out))
     86         return INVALID_OPERATION;
     87 
     88     return OK;
     89 }
     90 
     91 int64_t CommonClock::localDurationToCommonDuration(int64_t localDur) const {
     92     int64_t ret;
     93     duration_trans_.doForwardTransform(localDur, &ret);
     94     return ret;
     95 }
     96 
     97 void CommonClock::setBasis(int64_t local, int64_t common) {
     98     Mutex::Autolock lock(&lock_);
     99 
    100     cur_trans_.a_zero = local;
    101     cur_trans_.b_zero = common;
    102     cur_trans_valid_ = true;
    103 }
    104 
    105 void CommonClock::resetBasis() {
    106     Mutex::Autolock lock(&lock_);
    107 
    108     cur_trans_.a_zero = 0;
    109     cur_trans_.b_zero = 0;
    110     cur_trans_valid_ = false;
    111 }
    112 
    113 status_t CommonClock::setSlew(int64_t change_time, int32_t ppm) {
    114     Mutex::Autolock lock(&lock_);
    115 
    116     int64_t new_local_basis;
    117     int64_t new_common_basis;
    118 
    119     if (cur_trans_valid_) {
    120         new_local_basis = change_time;
    121         if (!cur_trans_.doForwardTransform(change_time, &new_common_basis)) {
    122             ALOGE("Overflow when attempting to set slew rate to %d", ppm);
    123             return INVALID_OPERATION;
    124         }
    125     } else {
    126         new_local_basis = 0;
    127         new_common_basis = 0;
    128     }
    129 
    130     cur_slew_ = ppm;
    131     uint32_t n1 = local_to_common_freq_numer_;
    132     uint32_t n2 = 1000000 + cur_slew_;
    133 
    134     uint32_t d1 = local_to_common_freq_denom_;
    135     uint32_t d2 = 1000000;
    136 
    137     // n1/d1 has already been reduced, no need to do so here.
    138     LinearTransform::reduce(&n1, &d2);
    139     LinearTransform::reduce(&n2, &d1);
    140     LinearTransform::reduce(&n2, &d2);
    141 
    142     cur_trans_.a_zero = new_local_basis;
    143     cur_trans_.b_zero = new_common_basis;
    144     cur_trans_.a_to_b_numer = n1 * n2;
    145     cur_trans_.a_to_b_denom = d1 * d2;
    146 
    147     return OK;
    148 }
    149 
    150 }  // namespace android
    151