Add sleep(1).

doc/user-guide

@@ -187,6 +187,7 @@ Sortix comes with a number of home-made programs. Here is an overview:
 * `rm` - remove file
 * `rmdir` - remove empty directory
 * `sh` - alias for the shell
+* `sleep` - delay for a specified amount of time
 * `snake` - remake of the classic snake game
 * `sort` - sort lines of text files
 * `tail` - display end of file

utils/.gitignore

@@ -35,6 +35,7 @@ pwd
 rm
 rmdir
 sh
+sleep
 sort
 sortix-sh
 tail

utils/Makefile

@@ -46,6 +46,7 @@ pwd \
 rm \
 rmdir \
 sh \
+sleep \
 sort \
 sortix-sh \
 tail \

utils/sleep.cpp

@@ -0,0 +1,268 @@
+/*******************************************************************************
+
+    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;
+}