Functions to convert times between Unix and MS-DOS times. More...

#include "dostime.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

Include dependency graph for dostime.c:

Functions
time_t	dos2unixtime (dostime_t dostime)
	Convert a DOS time to a Unix time. More...

dostime_t	dostime (int year, int month, int day, int hour, int minute, int second)

dostime_t	maxdostime ()
	Return the maximum possible value . More...

dostime_t	mindostime ()
	Return the minimum possible value. More...

dostime_t	unix2dostime (time_t unix_time)
	Convert a Unix date to a DOS date. More...

Detailed Description

These functions make use of the old date and time format defined to implement the FAT file system. This is defined on the Microsoft website here:

https://msdn.microsoft.com/en-us/library/windows/desktop/ms724247%28v=vs.85%29.aspx

As a quick recap, we have:

Date (actually we view those as bit 16 to 31)

0-4    Day of the month (1-31)
5-8    Month (1 = January, 2 = February, and so on)
9-15   Year offset from 1980 (add 1980 to get actual year)

Time

0-4    Second divided by 2
5-10   Minute (0-59)
11-15  Hour (0-23 on a 24-hour clock)

Note: This implementation uses C code.

Definition in file dostime.c.

Function Documentation

time_t dos2unixtime ( dostime_t dostime )

This function returns the Unix time_t value (GMT/UTC time) from the DOS format (local) time dostime, where dostime is a four byte value (date in most significant word, time in least significant word), see dostime() function.

If the input DOS time is invalid, then the function returns -1.

Note: If the dostime is not valid (one of the parameters is out of range) then the function returns -1.

Parameters

[in] dostime A DOS time value as found in a zip file.

Returns: The DOS time converted to a Unix time or -1.

See Also: dostime()

Todo:: Maximum for tm_mday depends on month/year.

Definition at line 131 of file dostime.c.

Referenced by main(), zipios::ZipCentralDirectoryEntry::read(), zipios::ZipLocalEntry::read(), and zipios::FileEntry::setTime().

dostime_t dostime	(	int	year,
		int	month,
		int	day,
		int	hour,
		int	minute,
		int	second
	)

Definition at line 188 of file dostime.c.

Referenced by zipios::ZipCentralDirectoryEntry::read(), zipios::ZipLocalEntry::read(), unix2dostime(), zipios::ZipCentralDirectoryEntry::write(), and zipios::ZipLocalEntry::write().

dostime_t maxdostime ( )

This function returns the maximum DOS time that can be represented in a dostime_t parameter.

At this time we use a 32 bit field (like the Zip archive) so the maximum is Dec 31, 2107 23:59:59.

Note: To get the corresponding Unix time, use the dos2unixtime() as in:

time_t max(dos2unixtime(maxdostime()));

Returns: The largest possible DOS time.

Definition at line 105 of file dostime.c.

dostime_t mindostime ( )

This function returns the minimum DOS time that can be represented in a dostime_t parameter.

At this time we use a 32 bit field (like the Zip archive) so the maximum is Dec 31, 2107 23:59:59.

Note: To get the corresponding Unix time, use the dos2unixtime() as in:

time_t min(dos2unixtime(mindostime()));

Returns: The smallest possible DOS time.

Definition at line 81 of file dostime.c.

dostime_t unix2dostime ( time_t unix_time )

This function return the Unix time_t converted in DOS format, rounded up to the next even second.

Parameters

[in] unix_time A Unix time_t value.

Returns: The Unix date in DOS format unless it is out of range for a DOS time and date in which case zero (0) is returned.

Definition at line 219 of file dostime.c.

References dostime().

Referenced by zipios::FileEntry::getTime(), main(), zipios::ZipCentralDirectoryEntry::write(), and zipios::ZipLocalEntry::write().