blob: 6c119369f1770414feac93fe7060089744e27bfa (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
|
;;
;; starlet/clocks.scm
;;
;; Copyright © 2021 Thomas White <taw@bitwiz.org.uk>
;;
;; This file is part of Starlet.
;;
;; Starlet is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program. If not, see <http://www.gnu.org/licenses/>.
;;
(define-module (starlet clock)
#:use-module (oop goops)
#:use-module (ice-9 exceptions)
#:export (<starlet-clock>
make-clock
stop-clock!
start-clock!
reverse-clock!
clock-expired?
<starlet-delayed-clock>
make-delayed-clock
clock-stopped?
clock-reversed?
elapsed-time
elapsed-fraction))
(define (time-now)
(let ((a (gettimeofday)))
(+ (car a)
(/ (cdr a)
1000000))))
;; "Real" clocks are straightforward objects for measuring differences in time
;; between now and some point in the past, allowing for temporarily "pausing"
;; the clock. The time difference cannot be negative: if the start time is in
;; the future, then "elapsed-time" will return 0.
(define-class <starlet-clock> (<object>)
(start-real-time
#:init-form (time-now)
#:init-keyword #:start-time
#:getter get-start-real-time
#:setter set-start-real-time!)
(start-elapsed-time
#:init-value 0
#:getter get-start-elapsed-time
#:setter set-start-elapsed-time!)
(stopped
#:init-value #f
#:getter clock-stopped?
#:setter set-clock-stopped!)
(expiration-time
#:init-value #f
#:init-keyword #:expiration-time
#:getter expiration-time)
(reversed
#:init-value #f
#:getter clock-reversed?
#:setter set-clock-reversed!))
(define* (make-clock
#:key (expiration-time #f))
(make <starlet-clock>
#:expiration-time expiration-time))
(define (clock-expired? clock)
(> (elapsed-time clock)
(expiration-time clock)))
(define-method (elapsed-time (clock <starlet-clock>))
(if (clock-stopped? clock)
(get-start-elapsed-time clock)
(max 0
(if (clock-reversed? clock)
(- (get-start-elapsed-time clock)
(- (time-now)
(get-start-real-time clock)))
(+ (get-start-elapsed-time clock)
(- (time-now)
(get-start-real-time clock)))))))
;; Stop the clock running
(define-method (stop-clock! (clock <starlet-clock>))
(set-start-elapsed-time! clock (elapsed-time clock))
(set-clock-stopped! clock #t))
;; Start the clock running (forwards)
(define-method (start-clock! (clock <starlet-clock>))
(set-start-elapsed-time! clock (elapsed-time clock))
(set-start-real-time! clock (time-now))
(set-clock-reversed! clock #f)
(set-clock-stopped! clock #f))
;; Start the clock running, backwards
(define-method (reverse-clock! (clock <starlet-clock>))
(set-start-elapsed-time! clock (elapsed-time clock))
(set-start-real-time! clock (time-now))
(set-clock-reversed! clock #t)
(set-clock-stopped! clock #f))
;; Delayed clocks refer to a parent clock for anything to do with "real" time.
;; Note, however, that the parent clock can be another delayed clock.
(define-class <starlet-delayed-clock> (<object>)
(parent
#:init-form (error "Parent clock must be specified")
#:init-keyword #:parent
#:getter get-parent-clock)
(delay-time
#:init-form (error "Delay time must be specified")
#:init-keyword #:delay-time
#:getter get-delay-time)
(duration
#:init-value #f
#:init-keyword #:duration
#:getter get-duration))
(define-method (clock-stopped? (clock <starlet-delayed-clock>))
(clock-stopped? (get-parent-clock clock)))
(define-method (clock-reversed? (clock <starlet-delayed-clock>))
(clock-reversed? (get-parent-clock clock)))
(define-method (elapsed-time (clock <starlet-delayed-clock>))
(max 0 (- (elapsed-time (get-parent-clock clock))
(get-delay-time clock))))
(define-method (elapsed-fraction (clock <starlet-delayed-clock>))
(if (= (get-duration clock) 0)
(if (> (elapsed-time clock) 0)
1.0
0.0)
(min 1.0
(/ (elapsed-time clock)
(get-duration clock)))))
(define-method (stop-clock! (clock <starlet-delayed-clock>))
(error "Can only stop a top-level clock."))
(define-method (start-clock! (clock <starlet-delayed-clock>))
(error "Can only start a top-level clock."))
(define-method (reverse-clock! (clock <starlet-delayed-clock>))
(error "Can only reverse a top-level clock."))
(define (make-delayed-clock clock delay-time duration)
(make <starlet-delayed-clock>
#:parent clock
#:delay-time delay-time
#:duration duration))
|
