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 /// Implementation of format_provider<T> for duration types.
56 /// The options string of a duration type has the grammar:
58 /// duration_options ::= [unit][show_unit [number_options]]
59 /// unit ::= `h`|`m`|`s`|`ms|`us`|`ns`
60 /// show_unit ::= `+` | `-`
61 /// number_options ::= options string for a integral or floating point type
64 /// =================================
65 /// | options | Input | Output |
66 /// =================================
68 /// | "ms" | 1s | 1000 ms |
69 /// | "ms-" | 1s | 1000 |
70 /// | "ms-n" | 1s | 1,000 |
71 /// | "" | 1.0s | 1.00 s |
72 /// =================================
74 /// If the unit of the duration type is not one of the units specified above,
75 /// it is still possible to format it, provided you explicitly request a
76 /// display unit or you request that the unit is not displayed.
79 template <typename Period> struct unit { static const char value[]; };
80 template <typename Period> const char unit<Period>::value[] = "";
82 template <> struct unit<std::ratio<3600>> { static const char value[]; };
83 template <> struct unit<std::ratio<60>> { static const char value[]; };
84 template <> struct unit<std::ratio<1>> { static const char value[]; };
85 template <> struct unit<std::milli> { static const char value[]; };
86 template <> struct unit<std::micro> { static const char value[]; };
87 template <> struct unit<std::nano> { static const char value[]; };
90 template <typename Rep, typename Period>
91 struct format_provider<std::chrono::duration<Rep, Period>> {
93 typedef std::chrono::duration<Rep, Period> Dur;
94 typedef typename std::conditional<
95 std::chrono::treat_as_floating_point<Rep>::value, double, intmax_t>::type
98 template <typename AsPeriod> static InternalRep getAs(const Dur &D) {
99 using namespace std::chrono;
100 return duration_cast<duration<InternalRep, AsPeriod>>(D).count();
103 static std::pair<InternalRep, StringRef> consumeUnit(StringRef &Style,
105 using namespace std::chrono;
106 if (Style.consume_front("ns"))
107 return {getAs<std::nano>(D), "ns"};
108 if (Style.consume_front("us"))
109 return {getAs<std::micro>(D), "us"};
110 if (Style.consume_front("ms"))
111 return {getAs<std::milli>(D), "ms"};
112 if (Style.consume_front("s"))
113 return {getAs<std::ratio<1>>(D), "s"};
114 if (Style.consume_front("m"))
115 return {getAs<std::ratio<60>>(D), "m"};
116 if (Style.consume_front("h"))
117 return {getAs<std::ratio<3600>>(D), "h"};
118 return {D.count(), detail::unit<Period>::value};
121 static bool consumeShowUnit(StringRef &Style) {
124 if (Style.consume_front("-"))
126 if (Style.consume_front("+"))
128 assert(0 && "Unrecognised duration format");
133 static void format(const Dur &D, llvm::raw_ostream &Stream, StringRef Style) {
136 std::tie(count, unit) = consumeUnit(Style, D);
137 bool show_unit = consumeShowUnit(Style);
139 format_provider<InternalRep>::format(count, Stream, Style);
142 assert(!unit.empty());
143 Stream << " " << unit;
150 #endif // LLVM_SUPPORT_CHRONO_H