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sortix--sortix/utils/sleep.cpp
Jonas 'Sortie' Termansen d56dcafd27 Add sleep(1).
2014-11-26 23:34:14 +01:00

268 lines
6.9 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2014.
This program 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/>.
sleep.cpp
Suspend execution for an interval of time.
*******************************************************************************/
#include <ctype.h>
#include <errno.h>
#include <error.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <timespec.h>
bool is_valid_interval(const char* string)
{
size_t index = 0;
while ( '0' <= string[index] && string[index] <= '9' )
index++;
if ( string[index] == '.' )
{
index++;
while ( '0' <= string[index] && string[index] <= '9' )
index++;
if ( index == 1 && string[index-1] == '.' )
return false;
}
if ( index == 0 )
return false;
return strcmp(string + index, "ns") == 0 ||
strcmp(string + index, "us") == 0 ||
strcmp(string + index, "ms") == 0 ||
strcmp(string + index, "") == 0 ||
strcmp(string + index, "s") == 0 ||
strcmp(string + index, "m") == 0 ||
strcmp(string + index, "h") == 0 ||
strcmp(string + index, "d") == 0;
}
struct timespec parse_interval(const char* string)
{
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = 0;
size_t index = 0;
while ( '0' <= string[index] && string[index] <= '9' )
{
char c = string[index++];
// TODO: Prevent the multiplication from overflowing!
ts.tv_sec = ts.tv_sec * 10;
// TODO: Prevent the addition from overflowing!
ts.tv_sec += c - '0';
}
if ( string[index] == '.' )
{
index++;
// Pick 9 digits as nanoseconds.
long contribution = 100L * 1000L * 1000L;
while ( contribution && '0' <= string[index] && string[index] <= '9' )
{
char c = string[index++];
ts.tv_nsec += (c - '0') * contribution;
contribution /= 10;
}
// Remember whether there are more non-zero digits we didn't handle.
bool any_non_zero_digits = false;
for ( size_t i = index; string[i]; i++ )
{
if ( !('0' <= string[i] && string[i] <= '9') )
break;
if ( string[i] - '0' != 0 )
any_non_zero_digits = true;
}
// If there are more digits we didn't handle, we'll round based on that.
if ( '0' <= string[index] && string[index] <= '9' )
{
char c = string[index++];
if ( 5 <= c - '0' )
ts.tv_nsec++;
if ( ts.tv_nsec == 1000000000L )
{
ts.tv_nsec = 0;
// TODO: This could overflow, which case we shouldn't have added
// 1 to tv_nsec regardless.
ts.tv_sec++;
}
}
// If all the digits we handled were zeroes, but there were some obscure
// non-zero digits we didn't handle, we'll wait at least a nanosecond.
if ( ts.tv_sec == 0 && ts.tv_nsec == 0 && any_non_zero_digits )
ts.tv_nsec = 1;
}
if ( !strcmp(string + index, "ns") )
{
ts.tv_nsec = ts.tv_sec % 1000000000L;
ts.tv_sec /= 1000000000L;
}
if ( !strcmp(string + index, "us") )
{
ts.tv_nsec /= 1000000L;
ts.tv_nsec += (ts.tv_sec % 1000000L) * 1000L;
ts.tv_sec /= 1000000L;
}
if ( !strcmp(string + index, "ms") )
{
ts.tv_nsec /= 1000L;
ts.tv_nsec += (ts.tv_sec % 1000L) * 100000L;
ts.tv_sec /= 1000L;
}
if ( !strcmp(string + index, "") || !strcmp(string + index, "s") )
{
}
if ( !strcmp(string + index, "m") )
{
// TODO: Properly handle overflow here!
ts.tv_nsec *= 60;
ts.tv_sec *= 60;
ts = timespec_canonalize(ts);
}
if ( !strcmp(string + index, "h") )
{
// TODO: Properly handle overflow here!
ts.tv_nsec *= 3600;
ts.tv_sec *= 3600;
ts = timespec_canonalize(ts);
}
if ( !strcmp(string + index, "d") )
{
// TODO: Properly handle overflow here!
ts.tv_nsec *= 86400;
ts.tv_sec *= 86400;
ts = timespec_canonalize(ts);
}
return ts;
}
static void compact_arguments(int* argc, char*** argv)
{
for ( int i = 0; i < *argc; i++ )
{
while ( i < *argc && !(*argv)[i] )
{
for ( int n = i; n < *argc; n++ )
(*argv)[n] = (*argv)[n+1];
(*argc)--;
}
}
}
static void help(FILE* fp, const char* argv0)
{
fprintf(fp, "Usage: %s [OPTION]... NUMBER[SUFFIX]...\n", argv0);
fprintf(fp, "Pause for NUMBER seconds. SUFFIX may be 's' for seconds (the default),\n");
fprintf(fp, "'m' for minutes, 'h' for hours or 'd' for days. Unlike most implementations\n");
fprintf(fp, "that require NUMBER be an integer, here NUMBER may be an arbitrary floating\n");
fprintf(fp, "point number. Given two or more arguments, pause for the amount of time\n");
fprintf(fp, "specified by the sum of their values.\n");
fprintf(fp, "\n");
fprintf(fp, " --help display this help and exit\n");
fprintf(fp, " --version output version information and exit\n");
}
static void version(FILE* fp, const char* argv0)
{
fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
fprintf(fp, "License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.\n");
fprintf(fp, "This is free software: you are free to change and redistribute it.\n");
fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n");
}
int main(int argc, char* argv[])
{
setlocale(LC_ALL, "");
const char* argv0 = argv[0];
for ( int i = 1; i < argc; i++ )
{
const char* arg = argv[i];
if ( arg[0] != '-' || !arg[1] )
continue;
argv[i] = NULL;
if ( !strcmp(arg, "--") )
break;
if ( arg[1] != '-' )
{
while ( char c = *++arg ) switch ( c )
{
default:
fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
help(stderr, argv0);
exit(1);
}
}
else if ( !strcmp(arg, "--help") )
help(stdout, argv0), exit(0);
else if ( !strcmp(arg, "--version") )
version(stdout, argv0), exit(0);
else
{
fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
help(stderr, argv0);
exit(1);
}
}
compact_arguments(&argc, &argv);
if ( argc < 2 )
{
error(0, errno, "missing operand");
fprintf(stderr, "Try '%s --help' for more information.\n", argv[0]);
exit(1);
}
struct timespec ts = timespec_nul();
for ( int i = 1; i < argc; i++ )
{
const char* arg = argv[i];
if ( !is_valid_interval(arg) )
{
error(0, errno, "invalid sleep interval `%s'", arg);
fprintf(stderr, "Try '%s --help' for more information.\n", argv[0]);
exit(1);
}
ts = timespec_add(ts, parse_interval(arg));
}
while ( ts.tv_sec || ts.tv_nsec )
{
if ( clock_nanosleep(CLOCK_REALTIME, 0, &ts, &ts) != 0 )
error(1, errno, "clock_nanosleep");
}
return 0;
}