1//===- llvm/Support/Chrono.h - Utilities for Timing Manipulation-*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_SUPPORT_CHRONO_H
10#define LLVM_SUPPORT_CHRONO_H
11
12#include "llvm/Support/Compiler.h"
13#include "llvm/Support/FormatProviders.h"
14
15#include <chrono>
16#include <ctime>
17#include <ratio>
18
19namespace llvm {
20
21class raw_ostream;
22
23namespace sys {
24
25/// A time point on the system clock. This is provided for two reasons:
26/// - to insulate us against subtle differences in behavior to differences in
27/// system clock precision (which is implementation-defined and differs
28/// between platforms).
29/// - to shorten the type name
30/// The default precision is nanoseconds. If you need a specific precision
31/// specify it explicitly. If unsure, use the default. If you need a time point
32/// on a clock other than the system_clock, use std::chrono directly.
33template <typename D = std::chrono::nanoseconds>
34using TimePoint = std::chrono::time_point<std::chrono::system_clock, D>;
35
36// utc_clock and utc_time are only available since C++20. Add enough code to
37// support formatting date/time in UTC.
38class UtcClock : public std::chrono::system_clock {};
39
40template <typename D = std::chrono::nanoseconds>
41using UtcTime = std::chrono::time_point<UtcClock, D>;
42
43/// Convert a std::time_t to a UtcTime
44inline UtcTime<std::chrono::seconds> toUtcTime(std::time_t T) {
45 using namespace std::chrono;
46 return UtcTime<seconds>(seconds(T));
47}
48
49/// Convert a TimePoint to std::time_t
50inline std::time_t toTimeT(TimePoint<> TP) {
51 using namespace std::chrono;
52 return system_clock::to_time_t(
53 t: time_point_cast<system_clock::time_point::duration>(t: TP));
54}
55
56/// Convert a UtcTime to std::time_t
57inline std::time_t toTimeT(UtcTime<> TP) {
58 using namespace std::chrono;
59 return system_clock::to_time_t(t: time_point<system_clock, seconds>(
60 duration_cast<seconds>(d: TP.time_since_epoch())));
61}
62
63/// Convert a std::time_t to a TimePoint
64inline TimePoint<std::chrono::seconds>
65toTimePoint(std::time_t T) {
66 using namespace std::chrono;
67 return time_point_cast<seconds>(t: system_clock::from_time_t(t: T));
68}
69
70/// Convert a std::time_t + nanoseconds to a TimePoint
71inline TimePoint<>
72toTimePoint(std::time_t T, uint32_t nsec) {
73 using namespace std::chrono;
74 return time_point_cast<nanoseconds>(t: system_clock::from_time_t(t: T))
75 + nanoseconds(nsec);
76}
77
78} // namespace sys
79
80raw_ostream &operator<<(raw_ostream &OS, sys::TimePoint<> TP);
81raw_ostream &operator<<(raw_ostream &OS, sys::UtcTime<> TP);
82
83/// Format provider for TimePoint<>
84///
85/// The options string is a strftime format string, with extensions:
86/// - %L is millis: 000-999
87/// - %f is micros: 000000-999999
88/// - %N is nanos: 000000000 - 999999999
89///
90/// If no options are given, the default format is "%Y-%m-%d %H:%M:%S.%N".
91template <>
92struct format_provider<sys::TimePoint<>> {
93 static void format(const sys::TimePoint<> &TP, llvm::raw_ostream &OS,
94 StringRef Style);
95};
96
97template <> struct format_provider<sys::UtcTime<std::chrono::seconds>> {
98 static void format(const sys::UtcTime<std::chrono::seconds> &TP,
99 llvm::raw_ostream &OS, StringRef Style);
100};
101
102namespace detail {
103template <typename Period> struct unit { static const char value[]; };
104template <typename Period> const char unit<Period>::value[] = "";
105
106template <> struct unit<std::ratio<3600>> { static const char value[]; };
107template <> struct unit<std::ratio<60>> { static const char value[]; };
108template <> struct unit<std::ratio<1>> { static const char value[]; };
109template <> struct unit<std::milli> { static const char value[]; };
110template <> struct unit<std::micro> { static const char value[]; };
111template <> struct unit<std::nano> { static const char value[]; };
112} // namespace detail
113
114/// Implementation of format_provider<T> for duration types.
115///
116/// The options string of a duration type has the grammar:
117///
118/// duration_options ::= [unit][show_unit [number_options]]
119/// unit ::= `h`|`m`|`s`|`ms|`us`|`ns`
120/// show_unit ::= `+` | `-`
121/// number_options ::= options string for a integral or floating point type
122///
123/// Examples
124/// =================================
125/// | options | Input | Output |
126/// =================================
127/// | "" | 1s | 1 s |
128/// | "ms" | 1s | 1000 ms |
129/// | "ms-" | 1s | 1000 |
130/// | "ms-n" | 1s | 1,000 |
131/// | "" | 1.0s | 1.00 s |
132/// =================================
133///
134/// If the unit of the duration type is not one of the units specified above,
135/// it is still possible to format it, provided you explicitly request a
136/// display unit or you request that the unit is not displayed.
137
138template <typename Rep, typename Period>
139struct format_provider<std::chrono::duration<Rep, Period>> {
140private:
141 typedef std::chrono::duration<Rep, Period> Dur;
142 typedef std::conditional_t<std::chrono::treat_as_floating_point<Rep>::value,
143 double, intmax_t>
144 InternalRep;
145
146 template <typename AsPeriod> static InternalRep getAs(const Dur &D) {
147 using namespace std::chrono;
148 return duration_cast<duration<InternalRep, AsPeriod>>(D).count();
149 }
150
151 static std::pair<InternalRep, StringRef> consumeUnit(StringRef &Style,
152 const Dur &D) {
153 using namespace std::chrono;
154 if (Style.consume_front(Prefix: "ns"))
155 return {getAs<std::nano>(D), "ns"};
156 if (Style.consume_front(Prefix: "us"))
157 return {getAs<std::micro>(D), "us"};
158 if (Style.consume_front(Prefix: "ms"))
159 return {getAs<std::milli>(D), "ms"};
160 if (Style.consume_front(Prefix: "s"))
161 return {getAs<std::ratio<1>>(D), "s"};
162 if (Style.consume_front(Prefix: "m"))
163 return {getAs<std::ratio<60>>(D), "m"};
164 if (Style.consume_front(Prefix: "h"))
165 return {getAs<std::ratio<3600>>(D), "h"};
166 return {D.count(), detail::unit<Period>::value};
167 }
168
169 static bool consumeShowUnit(StringRef &Style) {
170 if (Style.empty())
171 return true;
172 if (Style.consume_front(Prefix: "-"))
173 return false;
174 if (Style.consume_front(Prefix: "+"))
175 return true;
176 assert(0 && "Unrecognised duration format");
177 return true;
178 }
179
180public:
181 static void format(const Dur &D, llvm::raw_ostream &Stream, StringRef Style) {
182 InternalRep count;
183 StringRef unit;
184 std::tie(count, unit) = consumeUnit(Style, D);
185 bool show_unit = consumeShowUnit(Style);
186
187 format_provider<InternalRep>::format(count, Stream, Style);
188
189 if (show_unit) {
190 assert(!unit.empty());
191 Stream << " " << unit;
192 }
193 }
194};
195
196} // namespace llvm
197
198#endif // LLVM_SUPPORT_CHRONO_H
199

source code of include/llvm-20/llvm/Support/Chrono.h