Source code
Revision control
Copy as Markdown
Other Tools
/*
* Copyright 2025 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#import "AudioTimeStamp+Nanoseconds.h"
#include <mach/mach_time.h>
#include "rtc_base/checks.h"
std::optional<int64_t> AudioTimeStampGetNanoseconds(
const AudioTimeStamp* timeStamp) {
if (!timeStamp || ((timeStamp->mFlags & kAudioTimeStampHostTimeValid) == 0) ||
timeStamp->mHostTime == 0) {
return std::nullopt;
}
static mach_timebase_info_data_t mach_timebase;
if (mach_timebase.denom == 0) {
if (mach_timebase_info(&mach_timebase) != KERN_SUCCESS) {
RTC_DCHECK_NOTREACHED() << "mach_timebase_info bad return code";
return std::nullopt;
}
}
if (mach_timebase.denom == 0 || mach_timebase.numer == 0) {
RTC_DCHECK_NOTREACHED() << "mach_timebase_info provided bad data";
return std::nullopt;
}
uint64_t time_scaled = 0;
if (__builtin_umulll_overflow(
timeStamp->mHostTime, mach_timebase.numer, &time_scaled)) {
RTC_DCHECK_NOTREACHED() << "numeric overflow computing scaled host time";
return std::nullopt;
}
uint64_t nanoseconds = time_scaled / mach_timebase.denom;
if (nanoseconds >
static_cast<uint64_t>(std::numeric_limits<int64_t>::max())) {
RTC_DCHECK_NOTREACHED() << "numeric overflow computing nanoseconds";
return std::nullopt;
}
return static_cast<int64_t>(nanoseconds);
}