xref: /freebsd/crypto/heimdal/lib/roken/parse_time.3 (revision 9a14aa017b21c292740c00ee098195cd46642730)
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31.\" $Id: parse_time.3 14325 2004-10-30 22:34:28Z lha $
32.\"
33.Dd October 31, 2004
34.Dt PARSE_TIME 3
35.Os HEIMDAL
36.Sh NAME
37.Nm parse_time ,
38.Nm print_time_table ,
39.Nm unparse_time ,
40.Nm unparse_time_approx ,
41.Nd parse and unparse time intervals
42.Sh LIBRARY
43The roken library (libroken, -lroken)
44.Sh SYNOPSIS
45.Fd #include <parse_time.h>
46.Ft int
47.Fn parse_time "const char *timespec" "const char *def_unit"
48.Ft void
49.Fn print_time_table "FILE *f"
50.Ft size_t
51.Fn unparse_time "int seconds" "char *buf" "size_t len"
52.Ft size_t
53.Fn unparse_time_approx "int seconds" "char *buf" "size_t len"
54.Sh DESCRIPTION
55The
56.Fn parse_time
57function converts a the period of time specified in
58into a number of seconds.
59The
60.Fa timespec
61can be any number of
62.Aq number unit
63pairs separated by comma and whitespace. The number can be
64negative. Number without explicit units are taken as being
65.Fa def_unit .
66.Pp
67The
68.Fn unparse_time
69and
70.Fn unparse_time_approx
71does the opposite of
72.Fn parse_time ,
73that is they take a number of seconds and express that as human
74readable string.
75.Fa unparse_time
76produces an exact time, while
77.Fa unparse_time_approx
78restricts the result to only include one units.
79.Pp
80.Fn print_time_table
81prints a descriptive list of available units on the passed file
82descriptor.
83.Pp
84The possible units include:
85.Bl -tag -width "month" -compact -offset indent
86.It Li second , s
87.It Li minute , m
88.It Li hour , h
89.It day
90.It week
91seven days
92.It month
9330 days
94.It year
95365 days
96.El
97.Pp
98Units names can be arbitrarily abbreviated (as long as they are
99unique).
100.Sh RETURN VALUES
101.Fn parse_time
102returns the number of seconds that represents the expression in
103.Fa timespec
104or -1 on error.
105.Fn unparse_time
106and
107.Fn unparse_time_approx
108return the number of characters written to
109.Fa buf .
110if the return value is greater than or equal to the
111.Fa len
112argument, the string was too short and some of the printed characters
113were discarded.
114.Sh EXAMPLES
115.Bd -literal
116#include <stdio.h>
117#include <parse_time.h>
118
119int
120main(int argc, char **argv)
121{
122    int i;
123    int result;
124    char buf[128];
125    print_time_table(stdout);
126    for (i = 1; i < argc; i++) {
127	result = parse_time(argv[i], "second");
128	if(result == -1) {
129	    fprintf(stderr, "%s: parse error\\n", argv[i]);
130	    continue;
131	}
132	printf("--\\n");
133	printf("parse_time = %d\\n", result);
134	unparse_time(result, buf, sizeof(buf));
135	printf("unparse_time = %s\\n", buf);
136	unparse_time_approx(result, buf, sizeof(buf));
137	printf("unparse_time_approx = %s\\n", buf);
138    }
139    return 0;
140}
141.Ed
142.Bd -literal
143$ ./a.out "1 minute 30 seconds" "90 s" "1 y -1 s"
1441   year = 365 days
1451  month = 30 days
1461   week = 7 days
1471    day = 24 hours
1481   hour = 60 minutes
1491 minute = 60 seconds
1501 second
151--
152parse_time = 90
153unparse_time = 1 minute 30 seconds
154unparse_time_approx = 1 minute
155--
156parse_time = 90
157unparse_time = 1 minute 30 seconds
158unparse_time_approx = 1 minute
159--
160parse_time = 31535999
161unparse_time = 12 months 4 days 23 hours 59 minutes 59 seconds
162unparse_time_approx = 12 months
163.Ed
164.Sh BUGS
165Since
166.Fn parse_time
167returns -1 on error there is no way to parse "minus one second".
168Currently "s" at the end of units is ignored. This is a hack for
169English plural forms. If these functions are ever localised, this
170scheme will have to change.
171.\".Sh SEE ALSO
172.\".Xr parse_bytes 3
173.\".Xr parse_units 3
174