1 //===- llvm/Support/Chrono.h - Utilities for Timing Manipulation-*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLVM_SUPPORT_CHRONO_H
11 #define LLVM_SUPPORT_CHRONO_H
13 #include "llvm/Support/Compiler.h"
14 #include "llvm/Support/FormatProviders.h"
25 /// A time point on the system clock. This is provided for two reasons:
26 /// - to insulate us agains subtle differences in behavoir to differences in
27 /// system clock precision (which is implementation-defined and differs between
29 /// - to shorten the type name
30 /// The default precision is nanoseconds. If need a specific precision specify
31 /// it explicitly. If unsure, use the default. If you need a time point on a
32 /// clock other than the system_clock, use std::chrono directly.
33 template <typename D = std::chrono::nanoseconds>
34 using TimePoint = std::chrono::time_point<std::chrono::system_clock, D>;
36 /// Convert a TimePoint to std::time_t
37 LLVM_ATTRIBUTE_ALWAYS_INLINE inline std::time_t toTimeT(TimePoint<> TP) {
38 using namespace std::chrono;
39 return system_clock::to_time_t(
40 time_point_cast<system_clock::time_point::duration>(TP));
43 /// Convert a std::time_t to a TimePoint
44 LLVM_ATTRIBUTE_ALWAYS_INLINE inline TimePoint<std::chrono::seconds>
45 toTimePoint(std::time_t T) {
46 using namespace std::chrono;
47 return time_point_cast<seconds>(system_clock::from_time_t(T));
52 raw_ostream &operator<<(raw_ostream &OS, sys::TimePoint<> TP);
54 /// Format provider for TimePoint<>
56 /// The options string is a strftime format string, with extensions:
57 /// - %L is millis: 000-999
58 /// - %f is micros: 000000-999999
59 /// - %N is nanos: 000000000 - 999999999
61 /// If no options are given, the default format is "%Y-%m-%d %H:%M:%S.%N".
63 struct format_provider<sys::TimePoint<>> {
64 static void format(const sys::TimePoint<> &TP, llvm::raw_ostream &OS,
68 /// Implementation of format_provider<T> for duration types.
70 /// The options string of a duration type has the grammar:
72 /// duration_options ::= [unit][show_unit [number_options]]
73 /// unit ::= `h`|`m`|`s`|`ms|`us`|`ns`
74 /// show_unit ::= `+` | `-`
75 /// number_options ::= options string for a integral or floating point type
78 /// =================================
79 /// | options | Input | Output |
80 /// =================================
82 /// | "ms" | 1s | 1000 ms |
83 /// | "ms-" | 1s | 1000 |
84 /// | "ms-n" | 1s | 1,000 |
85 /// | "" | 1.0s | 1.00 s |
86 /// =================================
88 /// If the unit of the duration type is not one of the units specified above,
89 /// it is still possible to format it, provided you explicitly request a
90 /// display unit or you request that the unit is not displayed.
93 template <typename Period> struct unit { static const char value[]; };
94 template <typename Period> const char unit<Period>::value[] = "";
96 template <> struct unit<std::ratio<3600>> { static const char value[]; };
97 template <> struct unit<std::ratio<60>> { static const char value[]; };
98 template <> struct unit<std::ratio<1>> { static const char value[]; };
99 template <> struct unit<std::milli> { static const char value[]; };
100 template <> struct unit<std::micro> { static const char value[]; };
101 template <> struct unit<std::nano> { static const char value[]; };
102 } // namespace detail
104 template <typename Rep, typename Period>
105 struct format_provider<std::chrono::duration<Rep, Period>> {
107 typedef std::chrono::duration<Rep, Period> Dur;
108 typedef typename std::conditional<
109 std::chrono::treat_as_floating_point<Rep>::value, double, intmax_t>::type
112 template <typename AsPeriod> static InternalRep getAs(const Dur &D) {
113 using namespace std::chrono;
114 return duration_cast<duration<InternalRep, AsPeriod>>(D).count();
117 static std::pair<InternalRep, StringRef> consumeUnit(StringRef &Style,
119 using namespace std::chrono;
120 if (Style.consume_front("ns"))
121 return {getAs<std::nano>(D), "ns"};
122 if (Style.consume_front("us"))
123 return {getAs<std::micro>(D), "us"};
124 if (Style.consume_front("ms"))
125 return {getAs<std::milli>(D), "ms"};
126 if (Style.consume_front("s"))
127 return {getAs<std::ratio<1>>(D), "s"};
128 if (Style.consume_front("m"))
129 return {getAs<std::ratio<60>>(D), "m"};
130 if (Style.consume_front("h"))
131 return {getAs<std::ratio<3600>>(D), "h"};
132 return {D.count(), detail::unit<Period>::value};
135 static bool consumeShowUnit(StringRef &Style) {
138 if (Style.consume_front("-"))
140 if (Style.consume_front("+"))
142 assert(0 && "Unrecognised duration format");
147 static void format(const Dur &D, llvm::raw_ostream &Stream, StringRef Style) {
150 std::tie(count, unit) = consumeUnit(Style, D);
151 bool show_unit = consumeShowUnit(Style);
153 format_provider<InternalRep>::format(count, Stream, Style);
156 assert(!unit.empty());
157 Stream << " " << unit;
164 #endif // LLVM_SUPPORT_CHRONO_H