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1 : //===- llvm/Support/Chrono.h - Utilities for Timing Manipulation-*- C++ -*-===//
2 : //
3 : // The LLVM Compiler Infrastructure
4 : //
5 : // This file is distributed under the University of Illinois Open Source
6 : // License. See LICENSE.TXT for details.
7 : //
8 : //===----------------------------------------------------------------------===//
9 :
10 : #ifndef LLVM_SUPPORT_CHRONO_H
11 : #define LLVM_SUPPORT_CHRONO_H
12 :
13 : #include "llvm/Support/Compiler.h"
14 : #include "llvm/Support/FormatProviders.h"
15 :
16 : #include <chrono>
17 : #include <ctime>
18 :
19 : namespace llvm {
20 :
21 : class raw_ostream;
22 :
23 : namespace sys {
24 :
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
28 : /// platforms).
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>;
35 :
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));
41 : }
42 :
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));
48 : }
49 :
50 : } // namespace sys
51 :
52 : raw_ostream &operator<<(raw_ostream &OS, sys::TimePoint<> TP);
53 :
54 : /// Format provider for TimePoint<>
55 : ///
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
60 : ///
61 : /// If no options are given, the default format is "%Y-%m-%d %H:%M:%S.%N".
62 : template <>
63 : struct format_provider<sys::TimePoint<>> {
64 : static void format(const sys::TimePoint<> &TP, llvm::raw_ostream &OS,
65 : StringRef Style);
66 : };
67 :
68 : /// Implementation of format_provider<T> for duration types.
69 : ///
70 : /// The options string of a duration type has the grammar:
71 : ///
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
76 : ///
77 : /// Examples
78 : /// =================================
79 : /// | options | Input | Output |
80 : /// =================================
81 : /// | "" | 1s | 1 s |
82 : /// | "ms" | 1s | 1000 ms |
83 : /// | "ms-" | 1s | 1000 |
84 : /// | "ms-n" | 1s | 1,000 |
85 : /// | "" | 1.0s | 1.00 s |
86 : /// =================================
87 : ///
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.
91 :
92 : namespace detail {
93 : template <typename Period> struct unit { static const char value[]; };
94 : template <typename Period> const char unit<Period>::value[] = "";
95 :
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
103 :
104 : template <typename Rep, typename Period>
105 : struct format_provider<std::chrono::duration<Rep, Period>> {
106 : private:
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
110 : InternalRep;
111 :
112 : template <typename AsPeriod> static InternalRep getAs(const Dur &D) {
113 : using namespace std::chrono;
114 : return duration_cast<duration<InternalRep, AsPeriod>>(D).count();
115 : }
116 :
117 20 : static std::pair<InternalRep, StringRef> consumeUnit(StringRef &Style,
118 : const Dur &D) {
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 15 : return {D.count(), detail::unit<Period>::value};
133 : }
134 2 :
135 : static bool consumeShowUnit(StringRef &Style) {
136 : if (Style.empty())
137 : return true;
138 : if (Style.consume_front("-"))
139 : return false;
140 : if (Style.consume_front("+"))
141 : return true;
142 : assert(0 && "Unrecognised duration format");
143 : return true;
144 : }
145 :
146 : public:
147 : static void format(const Dur &D, llvm::raw_ostream &Stream, StringRef Style) {
148 : InternalRep count;
149 1 : StringRef unit;
150 : std::tie(count, unit) = consumeUnit(Style, D);
151 3 : bool show_unit = consumeShowUnit(Style);
152 :
153 : format_provider<InternalRep>::format(count, Stream, Style);
154 :
155 : if (show_unit) {
156 : assert(!unit.empty());
157 : Stream << " " << unit;
158 : }
159 : }
160 : };
161 :
162 : } // namespace llvm
163 :
164 : #endif // LLVM_SUPPORT_CHRONO_H
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