dsfml.system.clock source code

1 /*
2  * DSFML - The Simple and Fast Multimedia Library for D
3  *
4  * Copyright (c) 2013 - 2017 Jeremy DeHaan (dehaan.jeremiah@gmail.com)
5  *
6  * This software is provided 'as-is', without any express or implied warranty.
7  * In no event will the authors be held liable for any damages arising from the
8  * use of this software.
9  *
10  * Permission is granted to anyone to use this software for any purpose,
11  * including commercial applications, and to alter it and redistribute it
12  * freely, subject to the following restrictions:
13  *
14  * 1. The origin of this software must not be misrepresented; you must not claim
15  * that you wrote the original software. If you use this software in a product,
16  * an acknowledgment in the product documentation would be appreciated but is
17  * not required.
18  *
19  * 2. Altered source versions must be plainly marked as such, and must not be
20  * misrepresented as being the original software.
21  *
22  * 3. This notice may not be removed or altered from any source distribution
23  */
24 
25 /**
26  * Clock is a lightweight class for measuring time.
27  *
28  * Its provides the most precise time that the underlying OS can achieve
29  * (generally microseconds or nanoseconds). It also ensures monotonicity, which
30  * means that the returned time can never go backward, even if the system time
31  * is changed.
32  *
33  * Example:
34  * ---
35  * auto clock = Clock();
36  * ...
37  * Duration duration1 = clock.getElapsedTime();
38  * ...
39  * Duration duration2 = clock.restart();
40  * ---
41  *
42  * $(PARA The Duration value ($(I core.time.Duration)) returned by the clock can
43  * then be converted to a number of seconds, milliseconds or even microseconds.)
44  *
45  * See_Also:
46  * $(LINK2 https://dlang.org/library/core/time/duration.html, Duration)
47  */
48 module dsfml.system.clock;
49 
50 public import core.time;
51 
52 /**
53  * Utility class that measures the elapsed time.
54  */
55 class Clock
56 {
57 	package MonoTime m_startTime;
58 	private alias currTime = MonoTime.currTime;
59 
60 	/// Default constructor.
61 	this()
62 	{
63 		m_startTime = currTime;
64 	}
65 
66 	/// Destructor
67 	~this()
68 	{
69 		import dsfml.system.config;
70 		mixin(destructorOutput);
71 	}
72 
73 	/**
74 	 * Get the elapsed time.
75 	 *
76 	 * This function returns the time elapsed since the last call to `restart()`
77 	 * (or the construction of the instance if `restart()` has not been called).
78 	 *
79 	 * Returns: Time elapsed.
80 	 */
81 	Duration getElapsedTime() const
82 	{
83 		return currTime - m_startTime;
84 	}
85 
86 	/**
87 	 * Restart the clock.
88 	 *
89 	 * This function puts the time counter back to zero. It also returns the
90 	 * time elapsed since the clock was started.
91 	 *
92 	 * Returns: Time elapsed.
93 	 */
94 	Duration restart()
95 	{
96 		MonoTime now = currTime;
97 		auto elapsed = now - m_startTime;
98 		m_startTime = now;
99 
100 		return elapsed;
101 	}
102 }
103 
104 unittest
105 {
106 	version(DSFML_Unittest_System)
107 	{
108 		import std.stdio;
109 		import dsfml.system.sleep;
110 		import std.math;
111 
112 		writeln("Unit test for Clock");
113 
114 		Clock clock = new Clock();
115 
116 		writeln("Counting Time for 5 seconds.(rounded to nearest second)");
117 
118 		while(clock.getElapsedTime().total!"seconds" < 5)
119 		{
120 			writeln(clock.getElapsedTime().total!"seconds");
121 			sleep(seconds(1));
122 		}
123 
124 		writeln();
125 	}
126 }