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dawn-cmake/third_party/abseil-cpp/absl/time/duration.cc

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// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// The implementation of the absl::Duration class, which is declared in
// //absl/time.h. This class behaves like a numeric type; it has no public
// methods and is used only through the operators defined here.
//
// Implementation notes:
//
// An absl::Duration is represented as
//
// rep_hi_ : (int64_t) Whole seconds
// rep_lo_ : (uint32_t) Fractions of a second
//
// The seconds value (rep_hi_) may be positive or negative as appropriate.
// The fractional seconds (rep_lo_) is always a positive offset from rep_hi_.
// The API for Duration guarantees at least nanosecond resolution, which
// means rep_lo_ could have a max value of 1B - 1 if it stored nanoseconds.
// However, to utilize more of the available 32 bits of space in rep_lo_,
// we instead store quarters of a nanosecond in rep_lo_ resulting in a max
// value of 4B - 1. This allows us to correctly handle calculations like
// 0.5 nanos + 0.5 nanos = 1 nano. The following example shows the actual
// Duration rep using quarters of a nanosecond.
//
// 2.5 sec = {rep_hi_=2, rep_lo_=2000000000} // lo = 4 * 500000000
// -2.5 sec = {rep_hi_=-3, rep_lo_=2000000000}
//
// Infinite durations are represented as Durations with the rep_lo_ field set
// to all 1s.
//
// +InfiniteDuration:
// rep_hi_ : kint64max
// rep_lo_ : ~0U
//
// -InfiniteDuration:
// rep_hi_ : kint64min
// rep_lo_ : ~0U
//
// Arithmetic overflows/underflows to +/- infinity and saturates.
#if defined(_MSC_VER)
#include <winsock2.h> // for timeval
#endif
#include <algorithm>
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cmath>
#include <cstdint>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <functional>
#include <limits>
#include <string>
#include "absl/base/casts.h"
#include "absl/base/macros.h"
#include "absl/numeric/int128.h"
#include "absl/strings/string_view.h"
#include "absl/strings/strip.h"
#include "absl/time/time.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace {
using time_internal::kTicksPerNanosecond;
using time_internal::kTicksPerSecond;
constexpr int64_t kint64max = std::numeric_limits<int64_t>::max();
constexpr int64_t kint64min = std::numeric_limits<int64_t>::min();
// Can't use std::isinfinite() because it doesn't exist on windows.
inline bool IsFinite(double d) {
if (std::isnan(d)) return false;
return d != std::numeric_limits<double>::infinity() &&
d != -std::numeric_limits<double>::infinity();
}
inline bool IsValidDivisor(double d) {
if (std::isnan(d)) return false;
return d != 0.0;
}
// Can't use std::round() because it is only available in C++11.
// Note that we ignore the possibility of floating-point over/underflow.
template <typename Double>
inline double Round(Double d) {
return d < 0 ? std::ceil(d - 0.5) : std::floor(d + 0.5);
}
// *sec may be positive or negative. *ticks must be in the range
// -kTicksPerSecond < *ticks < kTicksPerSecond. If *ticks is negative it
// will be normalized to a positive value by adjusting *sec accordingly.
inline void NormalizeTicks(int64_t* sec, int64_t* ticks) {
if (*ticks < 0) {
--*sec;
*ticks += kTicksPerSecond;
}
}
// Makes a uint128 from the absolute value of the given scalar.
inline uint128 MakeU128(int64_t a) {
uint128 u128 = 0;
if (a < 0) {
++u128;
++a; // Makes it safe to negate 'a'
a = -a;
}
u128 += static_cast<uint64_t>(a);
return u128;
}
// Makes a uint128 count of ticks out of the absolute value of the Duration.
inline uint128 MakeU128Ticks(Duration d) {
int64_t rep_hi = time_internal::GetRepHi(d);
uint32_t rep_lo = time_internal::GetRepLo(d);
if (rep_hi < 0) {
++rep_hi;
rep_hi = -rep_hi;
rep_lo = kTicksPerSecond - rep_lo;
}
uint128 u128 = static_cast<uint64_t>(rep_hi);
u128 *= static_cast<uint64_t>(kTicksPerSecond);
u128 += rep_lo;
return u128;
}
// Breaks a uint128 of ticks into a Duration.
inline Duration MakeDurationFromU128(uint128 u128, bool is_neg) {
int64_t rep_hi;
uint32_t rep_lo;
const uint64_t h64 = Uint128High64(u128);
const uint64_t l64 = Uint128Low64(u128);
if (h64 == 0) { // fastpath
const uint64_t hi = l64 / kTicksPerSecond;
rep_hi = static_cast<int64_t>(hi);
rep_lo = static_cast<uint32_t>(l64 - hi * kTicksPerSecond);
} else {
// kMaxRepHi64 is the high 64 bits of (2^63 * kTicksPerSecond).
// Any positive tick count whose high 64 bits are >= kMaxRepHi64
// is not representable as a Duration. A negative tick count can
// have its high 64 bits == kMaxRepHi64 but only when the low 64
// bits are all zero, otherwise it is not representable either.
const uint64_t kMaxRepHi64 = 0x77359400UL;
if (h64 >= kMaxRepHi64) {
if (is_neg && h64 == kMaxRepHi64 && l64 == 0) {
// Avoid trying to represent -kint64min below.
return time_internal::MakeDuration(kint64min);
}
return is_neg ? -InfiniteDuration() : InfiniteDuration();
}
const uint128 kTicksPerSecond128 = static_cast<uint64_t>(kTicksPerSecond);
const uint128 hi = u128 / kTicksPerSecond128;
rep_hi = static_cast<int64_t>(Uint128Low64(hi));
rep_lo =
static_cast<uint32_t>(Uint128Low64(u128 - hi * kTicksPerSecond128));
}
if (is_neg) {
rep_hi = -rep_hi;
if (rep_lo != 0) {
--rep_hi;
rep_lo = kTicksPerSecond - rep_lo;
}
}
return time_internal::MakeDuration(rep_hi, rep_lo);
}
// Convert between int64_t and uint64_t, preserving representation. This
// allows us to do arithmetic in the unsigned domain, where overflow has
// well-defined behavior. See operator+=() and operator-=().
//
// C99 7.20.1.1.1, as referenced by C++11 18.4.1.2, says, "The typedef
// name intN_t designates a signed integer type with width N, no padding
// bits, and a two's complement representation." So, we can convert to
// and from the corresponding uint64_t value using a bit cast.
inline uint64_t EncodeTwosComp(int64_t v) {
return absl::bit_cast<uint64_t>(v);
}
inline int64_t DecodeTwosComp(uint64_t v) { return absl::bit_cast<int64_t>(v); }
// Note: The overflow detection in this function is done using greater/less *or
// equal* because kint64max/min is too large to be represented exactly in a
// double (which only has 53 bits of precision). In order to avoid assigning to
// rep->hi a double value that is too large for an int64_t (and therefore is
// undefined), we must consider computations that equal kint64max/min as a
// double as overflow cases.
inline bool SafeAddRepHi(double a_hi, double b_hi, Duration* d) {
double c = a_hi + b_hi;
if (c >= static_cast<double>(kint64max)) {
*d = InfiniteDuration();
return false;
}
if (c <= static_cast<double>(kint64min)) {
*d = -InfiniteDuration();
return false;
}
*d = time_internal::MakeDuration(c, time_internal::GetRepLo(*d));
return true;
}
// A functor that's similar to std::multiplies<T>, except this returns the max
// T value instead of overflowing. This is only defined for uint128.
template <typename Ignored>
struct SafeMultiply {
uint128 operator()(uint128 a, uint128 b) const {
// b hi is always zero because it originated as an int64_t.
assert(Uint128High64(b) == 0);
// Fastpath to avoid the expensive overflow check with division.
if (Uint128High64(a) == 0) {
return (((Uint128Low64(a) | Uint128Low64(b)) >> 32) == 0)
? static_cast<uint128>(Uint128Low64(a) * Uint128Low64(b))
: a * b;
}
return b == 0 ? b : (a > kuint128max / b) ? kuint128max : a * b;
}
};
// Scales (i.e., multiplies or divides, depending on the Operation template)
// the Duration d by the int64_t r.
template <template <typename> class Operation>
inline Duration ScaleFixed(Duration d, int64_t r) {
const uint128 a = MakeU128Ticks(d);
const uint128 b = MakeU128(r);
const uint128 q = Operation<uint128>()(a, b);
const bool is_neg = (time_internal::GetRepHi(d) < 0) != (r < 0);
return MakeDurationFromU128(q, is_neg);
}
// Scales (i.e., multiplies or divides, depending on the Operation template)
// the Duration d by the double r.
template <template <typename> class Operation>
inline Duration ScaleDouble(Duration d, double r) {
Operation<double> op;
double hi_doub = op(time_internal::GetRepHi(d), r);
double lo_doub = op(time_internal::GetRepLo(d), r);
double hi_int = 0;
double hi_frac = std::modf(hi_doub, &hi_int);
// Moves hi's fractional bits to lo.
lo_doub /= kTicksPerSecond;
lo_doub += hi_frac;
double lo_int = 0;
double lo_frac = std::modf(lo_doub, &lo_int);
// Rolls lo into hi if necessary.
int64_t lo64 = Round(lo_frac * kTicksPerSecond);
Duration ans;
if (!SafeAddRepHi(hi_int, lo_int, &ans)) return ans;
int64_t hi64 = time_internal::GetRepHi(ans);
if (!SafeAddRepHi(hi64, lo64 / kTicksPerSecond, &ans)) return ans;
hi64 = time_internal::GetRepHi(ans);
lo64 %= kTicksPerSecond;
NormalizeTicks(&hi64, &lo64);
return time_internal::MakeDuration(hi64, lo64);
}
// Tries to divide num by den as fast as possible by looking for common, easy
// cases. If the division was done, the quotient is in *q and the remainder is
// in *rem and true will be returned.
inline bool IDivFastPath(const Duration num, const Duration den, int64_t* q,
Duration* rem) {
// Bail if num or den is an infinity.
if (time_internal::IsInfiniteDuration(num) ||
time_internal::IsInfiniteDuration(den))
return false;
int64_t num_hi = time_internal::GetRepHi(num);
uint32_t num_lo = time_internal::GetRepLo(num);
int64_t den_hi = time_internal::GetRepHi(den);
uint32_t den_lo = time_internal::GetRepLo(den);
if (den_hi == 0 && den_lo == kTicksPerNanosecond) {
// Dividing by 1ns
if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 1000000000) {
*q = num_hi * 1000000000 + num_lo / kTicksPerNanosecond;
*rem = time_internal::MakeDuration(0, num_lo % den_lo);
return true;
}
} else if (den_hi == 0 && den_lo == 100 * kTicksPerNanosecond) {
// Dividing by 100ns (common when converting to Universal time)
if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 10000000) {
*q = num_hi * 10000000 + num_lo / (100 * kTicksPerNanosecond);
*rem = time_internal::MakeDuration(0, num_lo % den_lo);
return true;
}
} else if (den_hi == 0 && den_lo == 1000 * kTicksPerNanosecond) {
// Dividing by 1us
if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 1000000) {
*q = num_hi * 1000000 + num_lo / (1000 * kTicksPerNanosecond);
*rem = time_internal::MakeDuration(0, num_lo % den_lo);
return true;
}
} else if (den_hi == 0 && den_lo == 1000000 * kTicksPerNanosecond) {
// Dividing by 1ms
if (num_hi >= 0 && num_hi < (kint64max - kTicksPerSecond) / 1000) {
*q = num_hi * 1000 + num_lo / (1000000 * kTicksPerNanosecond);
*rem = time_internal::MakeDuration(0, num_lo % den_lo);
return true;
}
} else if (den_hi > 0 && den_lo == 0) {
// Dividing by positive multiple of 1s
if (num_hi >= 0) {
if (den_hi == 1) {
*q = num_hi;
*rem = time_internal::MakeDuration(0, num_lo);
return true;
}
*q = num_hi / den_hi;
*rem = time_internal::MakeDuration(num_hi % den_hi, num_lo);
return true;
}
if (num_lo != 0) {
num_hi += 1;
}
int64_t quotient = num_hi / den_hi;
int64_t rem_sec = num_hi % den_hi;
if (rem_sec > 0) {
rem_sec -= den_hi;
quotient += 1;
}
if (num_lo != 0) {
rem_sec -= 1;
}
*q = quotient;
*rem = time_internal::MakeDuration(rem_sec, num_lo);
return true;
}
return false;
}
} // namespace
namespace time_internal {
// The 'satq' argument indicates whether the quotient should saturate at the
// bounds of int64_t. If it does saturate, the difference will spill over to
// the remainder. If it does not saturate, the remainder remain accurate,
// but the returned quotient will over/underflow int64_t and should not be used.
int64_t IDivDuration(bool satq, const Duration num, const Duration den,
Duration* rem) {
int64_t q = 0;
if (IDivFastPath(num, den, &q, rem)) {
return q;
}
const bool num_neg = num < ZeroDuration();
const bool den_neg = den < ZeroDuration();
const bool quotient_neg = num_neg != den_neg;
if (time_internal::IsInfiniteDuration(num) || den == ZeroDuration()) {
*rem = num_neg ? -InfiniteDuration() : InfiniteDuration();
return quotient_neg ? kint64min : kint64max;
}
if (time_internal::IsInfiniteDuration(den)) {
*rem = num;
return 0;
}
const uint128 a = MakeU128Ticks(num);
const uint128 b = MakeU128Ticks(den);
uint128 quotient128 = a / b;
if (satq) {
// Limits the quotient to the range of int64_t.
if (quotient128 > uint128(static_cast<uint64_t>(kint64max))) {
quotient128 = quotient_neg ? uint128(static_cast<uint64_t>(kint64min))
: uint128(static_cast<uint64_t>(kint64max));
}
}
const uint128 remainder128 = a - quotient128 * b;
*rem = MakeDurationFromU128(remainder128, num_neg);
if (!quotient_neg || quotient128 == 0) {
return Uint128Low64(quotient128) & kint64max;
}
// The quotient needs to be negated, but we need to carefully handle
// quotient128s with the top bit on.
return -static_cast<int64_t>(Uint128Low64(quotient128 - 1) & kint64max) - 1;
}
} // namespace time_internal
//
// Additive operators.
//
Duration& Duration::operator+=(Duration rhs) {
if (time_internal::IsInfiniteDuration(*this)) return *this;
if (time_internal::IsInfiniteDuration(rhs)) return *this = rhs;
const int64_t orig_rep_hi = rep_hi_;
rep_hi_ =
DecodeTwosComp(EncodeTwosComp(rep_hi_) + EncodeTwosComp(rhs.rep_hi_));
if (rep_lo_ >= kTicksPerSecond - rhs.rep_lo_) {
rep_hi_ = DecodeTwosComp(EncodeTwosComp(rep_hi_) + 1);
rep_lo_ -= kTicksPerSecond;
}
rep_lo_ += rhs.rep_lo_;
if (rhs.rep_hi_ < 0 ? rep_hi_ > orig_rep_hi : rep_hi_ < orig_rep_hi) {
return *this = rhs.rep_hi_ < 0 ? -InfiniteDuration() : InfiniteDuration();
}
return *this;
}
Duration& Duration::operator-=(Duration rhs) {
if (time_internal::IsInfiniteDuration(*this)) return *this;
if (time_internal::IsInfiniteDuration(rhs)) {
return *this = rhs.rep_hi_ >= 0 ? -InfiniteDuration() : InfiniteDuration();
}
const int64_t orig_rep_hi = rep_hi_;
rep_hi_ =
DecodeTwosComp(EncodeTwosComp(rep_hi_) - EncodeTwosComp(rhs.rep_hi_));
if (rep_lo_ < rhs.rep_lo_) {
rep_hi_ = DecodeTwosComp(EncodeTwosComp(rep_hi_) - 1);
rep_lo_ += kTicksPerSecond;
}
rep_lo_ -= rhs.rep_lo_;
if (rhs.rep_hi_ < 0 ? rep_hi_ < orig_rep_hi : rep_hi_ > orig_rep_hi) {
return *this = rhs.rep_hi_ >= 0 ? -InfiniteDuration() : InfiniteDuration();
}
return *this;
}
//
// Multiplicative operators.
//
Duration& Duration::operator*=(int64_t r) {
if (time_internal::IsInfiniteDuration(*this)) {
const bool is_neg = (r < 0) != (rep_hi_ < 0);
return *this = is_neg ? -InfiniteDuration() : InfiniteDuration();
}
return *this = ScaleFixed<SafeMultiply>(*this, r);
}
Duration& Duration::operator*=(double r) {
if (time_internal::IsInfiniteDuration(*this) || !IsFinite(r)) {
const bool is_neg = (std::signbit(r) != 0) != (rep_hi_ < 0);
return *this = is_neg ? -InfiniteDuration() : InfiniteDuration();
}
return *this = ScaleDouble<std::multiplies>(*this, r);
}
Duration& Duration::operator/=(int64_t r) {
if (time_internal::IsInfiniteDuration(*this) || r == 0) {
const bool is_neg = (r < 0) != (rep_hi_ < 0);
return *this = is_neg ? -InfiniteDuration() : InfiniteDuration();
}
return *this = ScaleFixed<std::divides>(*this, r);
}
Duration& Duration::operator/=(double r) {
if (time_internal::IsInfiniteDuration(*this) || !IsValidDivisor(r)) {
const bool is_neg = (std::signbit(r) != 0) != (rep_hi_ < 0);
return *this = is_neg ? -InfiniteDuration() : InfiniteDuration();
}
return *this = ScaleDouble<std::divides>(*this, r);
}
Duration& Duration::operator%=(Duration rhs) {
time_internal::IDivDuration(false, *this, rhs, this);
return *this;
}
double FDivDuration(Duration num, Duration den) {
// Arithmetic with infinity is sticky.
if (time_internal::IsInfiniteDuration(num) || den == ZeroDuration()) {
return (num < ZeroDuration()) == (den < ZeroDuration())
? std::numeric_limits<double>::infinity()
: -std::numeric_limits<double>::infinity();
}
if (time_internal::IsInfiniteDuration(den)) return 0.0;
double a =
static_cast<double>(time_internal::GetRepHi(num)) * kTicksPerSecond +
time_internal::GetRepLo(num);
double b =
static_cast<double>(time_internal::GetRepHi(den)) * kTicksPerSecond +
time_internal::GetRepLo(den);
return a / b;
}
//
// Trunc/Floor/Ceil.
//
Duration Trunc(Duration d, Duration unit) {
return d - (d % unit);
}
Duration Floor(const Duration d, const Duration unit) {
const absl::Duration td = Trunc(d, unit);
return td <= d ? td : td - AbsDuration(unit);
}
Duration Ceil(const Duration d, const Duration unit) {
const absl::Duration td = Trunc(d, unit);
return td >= d ? td : td + AbsDuration(unit);
}
//
// Factory functions.
//
Duration DurationFromTimespec(timespec ts) {
if (static_cast<uint64_t>(ts.tv_nsec) < 1000 * 1000 * 1000) {
int64_t ticks = ts.tv_nsec * kTicksPerNanosecond;
return time_internal::MakeDuration(ts.tv_sec, ticks);
}
return Seconds(ts.tv_sec) + Nanoseconds(ts.tv_nsec);
}
Duration DurationFromTimeval(timeval tv) {
if (static_cast<uint64_t>(tv.tv_usec) < 1000 * 1000) {
int64_t ticks = tv.tv_usec * 1000 * kTicksPerNanosecond;
return time_internal::MakeDuration(tv.tv_sec, ticks);
}
return Seconds(tv.tv_sec) + Microseconds(tv.tv_usec);
}
//
// Conversion to other duration types.
//
int64_t ToInt64Nanoseconds(Duration d) {
if (time_internal::GetRepHi(d) >= 0 &&
time_internal::GetRepHi(d) >> 33 == 0) {
return (time_internal::GetRepHi(d) * 1000 * 1000 * 1000) +
(time_internal::GetRepLo(d) / kTicksPerNanosecond);
}
return d / Nanoseconds(1);
}
int64_t ToInt64Microseconds(Duration d) {
if (time_internal::GetRepHi(d) >= 0 &&
time_internal::GetRepHi(d) >> 43 == 0) {
return (time_internal::GetRepHi(d) * 1000 * 1000) +
(time_internal::GetRepLo(d) / (kTicksPerNanosecond * 1000));
}
return d / Microseconds(1);
}
int64_t ToInt64Milliseconds(Duration d) {
if (time_internal::GetRepHi(d) >= 0 &&
time_internal::GetRepHi(d) >> 53 == 0) {
return (time_internal::GetRepHi(d) * 1000) +
(time_internal::GetRepLo(d) / (kTicksPerNanosecond * 1000 * 1000));
}
return d / Milliseconds(1);
}
int64_t ToInt64Seconds(Duration d) {
int64_t hi = time_internal::GetRepHi(d);
if (time_internal::IsInfiniteDuration(d)) return hi;
if (hi < 0 && time_internal::GetRepLo(d) != 0) ++hi;
return hi;
}
int64_t ToInt64Minutes(Duration d) {
int64_t hi = time_internal::GetRepHi(d);
if (time_internal::IsInfiniteDuration(d)) return hi;
if (hi < 0 && time_internal::GetRepLo(d) != 0) ++hi;
return hi / 60;
}
int64_t ToInt64Hours(Duration d) {
int64_t hi = time_internal::GetRepHi(d);
if (time_internal::IsInfiniteDuration(d)) return hi;
if (hi < 0 && time_internal::GetRepLo(d) != 0) ++hi;
return hi / (60 * 60);
}
double ToDoubleNanoseconds(Duration d) {
return FDivDuration(d, Nanoseconds(1));
}
double ToDoubleMicroseconds(Duration d) {
return FDivDuration(d, Microseconds(1));
}
double ToDoubleMilliseconds(Duration d) {
return FDivDuration(d, Milliseconds(1));
}
double ToDoubleSeconds(Duration d) {
return FDivDuration(d, Seconds(1));
}
double ToDoubleMinutes(Duration d) {
return FDivDuration(d, Minutes(1));
}
double ToDoubleHours(Duration d) {
return FDivDuration(d, Hours(1));
}
timespec ToTimespec(Duration d) {
timespec ts;
if (!time_internal::IsInfiniteDuration(d)) {
int64_t rep_hi = time_internal::GetRepHi(d);
uint32_t rep_lo = time_internal::GetRepLo(d);
if (rep_hi < 0) {
// Tweak the fields so that unsigned division of rep_lo
// maps to truncation (towards zero) for the timespec.
rep_lo += kTicksPerNanosecond - 1;
if (rep_lo >= kTicksPerSecond) {
rep_hi += 1;
rep_lo -= kTicksPerSecond;
}
}
ts.tv_sec = rep_hi;
if (ts.tv_sec == rep_hi) { // no time_t narrowing
ts.tv_nsec = rep_lo / kTicksPerNanosecond;
return ts;
}
}
if (d >= ZeroDuration()) {
ts.tv_sec = std::numeric_limits<time_t>::max();
ts.tv_nsec = 1000 * 1000 * 1000 - 1;
} else {
ts.tv_sec = std::numeric_limits<time_t>::min();
ts.tv_nsec = 0;
}
return ts;
}
timeval ToTimeval(Duration d) {
timeval tv;
timespec ts = ToTimespec(d);
if (ts.tv_sec < 0) {
// Tweak the fields so that positive division of tv_nsec
// maps to truncation (towards zero) for the timeval.
ts.tv_nsec += 1000 - 1;
if (ts.tv_nsec >= 1000 * 1000 * 1000) {
ts.tv_sec += 1;
ts.tv_nsec -= 1000 * 1000 * 1000;
}
}
tv.tv_sec = ts.tv_sec;
if (tv.tv_sec != ts.tv_sec) { // narrowing
if (ts.tv_sec < 0) {
tv.tv_sec = std::numeric_limits<decltype(tv.tv_sec)>::min();
tv.tv_usec = 0;
} else {
tv.tv_sec = std::numeric_limits<decltype(tv.tv_sec)>::max();
tv.tv_usec = 1000 * 1000 - 1;
}
return tv;
}
tv.tv_usec = static_cast<int>(ts.tv_nsec / 1000); // suseconds_t
return tv;
}
std::chrono::nanoseconds ToChronoNanoseconds(Duration d) {
return time_internal::ToChronoDuration<std::chrono::nanoseconds>(d);
}
std::chrono::microseconds ToChronoMicroseconds(Duration d) {
return time_internal::ToChronoDuration<std::chrono::microseconds>(d);
}
std::chrono::milliseconds ToChronoMilliseconds(Duration d) {
return time_internal::ToChronoDuration<std::chrono::milliseconds>(d);
}
std::chrono::seconds ToChronoSeconds(Duration d) {
return time_internal::ToChronoDuration<std::chrono::seconds>(d);
}
std::chrono::minutes ToChronoMinutes(Duration d) {
return time_internal::ToChronoDuration<std::chrono::minutes>(d);
}
std::chrono::hours ToChronoHours(Duration d) {
return time_internal::ToChronoDuration<std::chrono::hours>(d);
}
//
// To/From string formatting.
//
namespace {
// Formats a positive 64-bit integer in the given field width. Note that
// it is up to the caller of Format64() to ensure that there is sufficient
// space before ep to hold the conversion.
char* Format64(char* ep, int width, int64_t v) {
do {
--width;
*--ep = '0' + (v % 10); // contiguous digits
} while (v /= 10);
while (--width >= 0) *--ep = '0'; // zero pad
return ep;
}
// Helpers for FormatDuration() that format 'n' and append it to 'out'
// followed by the given 'unit'. If 'n' formats to "0", nothing is
// appended (not even the unit).
// A type that encapsulates how to display a value of a particular unit. For
// values that are displayed with fractional parts, the precision indicates
// where to round the value. The precision varies with the display unit because
// a Duration can hold only quarters of a nanosecond, so displaying information
// beyond that is just noise.
//
// For example, a microsecond value of 42.00025xxxxx should not display beyond 5
// fractional digits, because it is in the noise of what a Duration can
// represent.
struct DisplayUnit {
absl::string_view abbr;
int prec;
double pow10;
};
ABSL_CONST_INIT const DisplayUnit kDisplayNano = {"ns", 2, 1e2};
ABSL_CONST_INIT const DisplayUnit kDisplayMicro = {"us", 5, 1e5};
ABSL_CONST_INIT const DisplayUnit kDisplayMilli = {"ms", 8, 1e8};
ABSL_CONST_INIT const DisplayUnit kDisplaySec = {"s", 11, 1e11};
ABSL_CONST_INIT const DisplayUnit kDisplayMin = {"m", -1, 0.0}; // prec ignored
ABSL_CONST_INIT const DisplayUnit kDisplayHour = {"h", -1,
0.0}; // prec ignored
void AppendNumberUnit(std::string* out, int64_t n, DisplayUnit unit) {
char buf[sizeof("2562047788015216")]; // hours in max duration
char* const ep = buf + sizeof(buf);
char* bp = Format64(ep, 0, n);
if (*bp != '0' || bp + 1 != ep) {
out->append(bp, ep - bp);
out->append(unit.abbr.data(), unit.abbr.size());
}
}
// Note: unit.prec is limited to double's digits10 value (typically 15) so it
// always fits in buf[].
void AppendNumberUnit(std::string* out, double n, DisplayUnit unit) {
constexpr int kBufferSize = std::numeric_limits<double>::digits10;
const int prec = std::min(kBufferSize, unit.prec);
char buf[kBufferSize]; // also large enough to hold integer part
char* ep = buf + sizeof(buf);
double d = 0;
int64_t frac_part = Round(std::modf(n, &d) * unit.pow10);
int64_t int_part = d;
if (int_part != 0 || frac_part != 0) {
char* bp = Format64(ep, 0, int_part); // always < 1000
out->append(bp, ep - bp);
if (frac_part != 0) {
out->push_back('.');
bp = Format64(ep, prec, frac_part);
while (ep[-1] == '0') --ep;
out->append(bp, ep - bp);
}
out->append(unit.abbr.data(), unit.abbr.size());
}
}
} // namespace
// From Go's doc at https://golang.org/pkg/time/#Duration.String
// [FormatDuration] returns a string representing the duration in the
// form "72h3m0.5s". Leading zero units are omitted. As a special
// case, durations less than one second format use a smaller unit
// (milli-, micro-, or nanoseconds) to ensure that the leading digit
// is non-zero.
// Unlike Go, we format the zero duration as 0, with no unit.
std::string FormatDuration(Duration d) {
constexpr Duration kMinDuration = Seconds(kint64min);
std::string s;
if (d == kMinDuration) {
// Avoid needing to negate kint64min by directly returning what the
// following code should produce in that case.
s = "-2562047788015215h30m8s";
return s;
}
if (d < ZeroDuration()) {
s.append("-");
d = -d;
}
if (d == InfiniteDuration()) {
s.append("inf");
} else if (d < Seconds(1)) {
// Special case for durations with a magnitude < 1 second. The duration
// is printed as a fraction of a single unit, e.g., "1.2ms".
if (d < Microseconds(1)) {
AppendNumberUnit(&s, FDivDuration(d, Nanoseconds(1)), kDisplayNano);
} else if (d < Milliseconds(1)) {
AppendNumberUnit(&s, FDivDuration(d, Microseconds(1)), kDisplayMicro);
} else {
AppendNumberUnit(&s, FDivDuration(d, Milliseconds(1)), kDisplayMilli);
}
} else {
AppendNumberUnit(&s, IDivDuration(d, Hours(1), &d), kDisplayHour);
AppendNumberUnit(&s, IDivDuration(d, Minutes(1), &d), kDisplayMin);
AppendNumberUnit(&s, FDivDuration(d, Seconds(1)), kDisplaySec);
}
if (s.empty() || s == "-") {
s = "0";
}
return s;
}
namespace {
// A helper for ParseDuration() that parses a leading number from the given
// string and stores the result in *int_part/*frac_part/*frac_scale. The
// given string pointer is modified to point to the first unconsumed char.
bool ConsumeDurationNumber(const char** dpp, const char* ep, int64_t* int_part,
int64_t* frac_part, int64_t* frac_scale) {
*int_part = 0;
*frac_part = 0;
*frac_scale = 1; // invariant: *frac_part < *frac_scale
const char* start = *dpp;
for (; *dpp != ep; *dpp += 1) {
const int d = **dpp - '0'; // contiguous digits
if (d < 0 || 10 <= d) break;
if (*int_part > kint64max / 10) return false;
*int_part *= 10;
if (*int_part > kint64max - d) return false;
*int_part += d;
}
const bool int_part_empty = (*dpp == start);
if (*dpp == ep || **dpp != '.') return !int_part_empty;
for (*dpp += 1; *dpp != ep; *dpp += 1) {
const int d = **dpp - '0'; // contiguous digits
if (d < 0 || 10 <= d) break;
if (*frac_scale <= kint64max / 10) {
*frac_part *= 10;
*frac_part += d;
*frac_scale *= 10;
}
}
return !int_part_empty || *frac_scale != 1;
}
// A helper for ParseDuration() that parses a leading unit designator (e.g.,
// ns, us, ms, s, m, h) from the given string and stores the resulting unit
// in "*unit". The given string pointer is modified to point to the first
// unconsumed char.
bool ConsumeDurationUnit(const char** start, const char* end, Duration* unit) {
size_t size = end - *start;
switch (size) {
case 0:
return false;
default:
switch (**start) {
case 'n':
if (*(*start + 1) == 's') {
*start += 2;
*unit = Nanoseconds(1);
return true;
}
break;
case 'u':
if (*(*start + 1) == 's') {
*start += 2;
*unit = Microseconds(1);
return true;
}
break;
case 'm':
if (*(*start + 1) == 's') {
*start += 2;
*unit = Milliseconds(1);
return true;
}
break;
default:
break;
}
ABSL_FALLTHROUGH_INTENDED;
case 1:
switch (**start) {
case 's':
*unit = Seconds(1);
*start += 1;
return true;
case 'm':
*unit = Minutes(1);
*start += 1;
return true;
case 'h':
*unit = Hours(1);
*start += 1;
return true;
default:
return false;
}
}
}
} // namespace
// From Go's doc at https://golang.org/pkg/time/#ParseDuration
// [ParseDuration] parses a duration string. A duration string is
// a possibly signed sequence of decimal numbers, each with optional
// fraction and a unit suffix, such as "300ms", "-1.5h" or "2h45m".
// Valid time units are "ns", "us" "ms", "s", "m", "h".
bool ParseDuration(absl::string_view dur_sv, Duration* d) {
int sign = 1;
if (absl::ConsumePrefix(&dur_sv, "-")) {
sign = -1;
} else {
absl::ConsumePrefix(&dur_sv, "+");
}
if (dur_sv.empty()) return false;
// Special case for a string of "0".
if (dur_sv == "0") {
*d = ZeroDuration();
return true;
}
if (dur_sv == "inf") {
*d = sign * InfiniteDuration();
return true;
}
const char* start = dur_sv.data();
const char* end = start + dur_sv.size();
Duration dur;
while (start != end) {
int64_t int_part;
int64_t frac_part;
int64_t frac_scale;
Duration unit;
if (!ConsumeDurationNumber(&start, end, &int_part, &frac_part,
&frac_scale) ||
!ConsumeDurationUnit(&start, end, &unit)) {
return false;
}
if (int_part != 0) dur += sign * int_part * unit;
if (frac_part != 0) dur += sign * frac_part * unit / frac_scale;
}
*d = dur;
return true;
}
bool AbslParseFlag(absl::string_view text, Duration* dst, std::string*) {
return ParseDuration(text, dst);
}
std::string AbslUnparseFlag(Duration d) { return FormatDuration(d); }
bool ParseFlag(const std::string& text, Duration* dst, std::string* ) {
return ParseDuration(text, dst);
}
std::string UnparseFlag(Duration d) { return FormatDuration(d); }
ABSL_NAMESPACE_END
} // namespace absl
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