Date to 4 byte string

[Steve]

Hi All,

I have a registration code that currently has 4 bytes that are unused.
I'd like to store a future date in those 4 bytes. Is there a way to
convert a date to a 4 byte string?

When I do something like this,

string stringDate =
DateTime.Parse( "1/15/2210").ToBinary ().ToString("X" );

I get a hex # 15 characters long.

Any suggestions? I only have 4 bytes to work with to stay backward
compatible.

Thanks,
Steve

[Michael A. Covington]

Re: Date to 4 byte string


"Steve" <kilroy@harpser vices.comwrote in message
news:1bkui3doo8 icfp0jjd805s6nc cmpqsil1f@4ax.c om...

Hi All,
>
I have a registration code that currently has 4 bytes that are unused.
I'd like to store a future date in those 4 bytes. Is there a way to
convert a date to a 4 byte string?

Let's see. 4 bytes will hold an unsigned 32-bit integer. Convert the date
into number of days past some specific date, and store it as that.

[Peter Duniho]

Re: Date to 4 byte string

On 2007-11-05 09:57:51 -0800, Steve <kilroy@harpser vices.comsaid:

Hi All,
>
I have a registration code that currently has 4 bytes that are unused.
I'd like to store a future date in those 4 bytes. Is there a way to
convert a date to a 4 byte string?

Not in a general purpose way. However, you could easily pick a
specific reference date, and then store the total number of days from
that date as the future date. 4 bytes gives you a 32-bit counter, and
you can represent a date VERY far in the future with that as your
number of days. :)

Actually 32-bits is (as you can see from the above) a pretty large
amount of data for the kind of information you're trying to store. So
depending on your desires and needs, you could waste some space making
the 4 bytes a little more readable and likely still come up with
something usable. For example, one byte each for day of month and
month of year, and then two bytes for the year. That would still allow
you to represent absolute dates (rather than the relative suggested
above) through the year 65535. 65536 if you're willing to take
advantage of the fact that there's no 0 AD.

This all assumes the usual Western Gregorian calendar. Your mileage
may vary depending on other calendars you might use, if any.

Pete

[Ignacio Machin \( .NET/ C# MVP \)]

Re: Date to 4 byte string

Hi,

I think you could do it, you could use one byte for the day, one for the
month and you have two for the year.


--
Ignacio Machin

http://www.laceupsolutions.com

Mobile & warehouse Solutions.
"Steve" <kilroy@harpser vices.comwrote in message
news:1bkui3doo8 icfp0jjd805s6nc cmpqsil1f@4ax.c om...

Hi All,
>
I have a registration code that currently has 4 bytes that are unused.
I'd like to store a future date in those 4 bytes. Is there a way to
convert a date to a 4 byte string?
>
When I do something like this,
>
string stringDate =
DateTime.Parse( "1/15/2210").ToBinary ().ToString("X" );
>
I get a hex # 15 characters long.
>
Any suggestions? I only have 4 bytes to work with to stay backward
compatible.
>
Thanks,
Steve

[Alberto Poblacion]

Re: Date to 4 byte string

"Michael A. Covington" <mc@uga.eduwrot e in message
news:ewJ%23$X9H IHA.1184@TK2MSF TNGP04.phx.gbl. ..

"Steve" <kilroy@harpser vices.comwrote in message
news:1bkui3doo8 icfp0jjd805s6nc cmpqsil1f@4ax.c om...

>I have a registration code that currently has 4 bytes that are unused.
>I'd like to store a future date in those 4 bytes. Is there a way to
>convert a date to a 4 byte string?

>
Let's see. 4 bytes will hold an unsigned 32-bit integer. Convert the
date into number of days past some specific date, and store it as that.

Another possibility: Consider the date as a yyyymmdd string, for
instance, 20071231 (you can chhose a different format, of course, but this
one will be advantageous if you need to sort by date). Then store those 8
digits in your 4 bytes, 2 digits per byte. This will be easier to read than
"number of days from a specified date" if you ever have to look at a hex
dump of your data.

[Morten Wennevik [C# MVP]]

Re: Date to 4 byte string

Hi Steve,

This article may give you some clues. It's not written in C#, but the principles are the same. Use >and << for bit manipulation.

[Bit Fields and Packed Data]

http://webster.cs.ucr.edu/AoA/Windows/HTML/DataRepresentationa7.html

On Mon, 05 Nov 2007 18:57:51 +0100, Steve <kilroy@harpser vices.comwrote:

Hi All,
>
I have a registration code that currently has 4 bytes that are unused.
I'd like to store a future date in those 4 bytes. Is there a way to
convert a date to a 4 byte string?
>
When I do something like this,
>
string stringDate =
DateTime.Parse( "1/15/2210").ToBinary ().ToString("X" );
>
I get a hex # 15 characters long.
>
Any suggestions? I only have 4 bytes to work with to stay backward
compatible.
>
Thanks,
Steve
>

--
Happy coding!
Morten Wennevik [C# MVP]

[Jon Skeet [C# MVP]]

Re: Date to 4 byte string

Steve <kilroy@harpser vices.comwrote:

I have a registration code that currently has 4 bytes that are unused.
I'd like to store a future date in those 4 bytes. Is there a way to
convert a date to a 4 byte string?

One thing no-one else has mentioned: strings aren't comprised of bytes.
They're comprised of *characters*. Now, do you need a 4-byte data
structure of any description, or an actual 4 character string?

If you can use 4 bytes in an arbitrary fashion, using an int is likely
to be the best solution. 4 characters would be a different matter.

--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[=?Utf-8?B?UGV0ZXIgQnJvbWJlcmcgW0MjIE1WUF0=?=]

RE: Date to 4 byte string

Something like this?

int myDate = 20071105;
byte[] b = BitConverter.Ge tBytes(myDate);
Console.WriteLi ne(b.Length.ToS tring() + " bytes."); // reads "4 bytes"
-- Peter

http://www.eggheadcafe.com

unBlog: http://petesbloggerama.blogspot.com
BlogMetaFinder: http://www.blogmetafinder.com



"Steve" wrote:

Hi All,
>
I have a registration code that currently has 4 bytes that are unused.
I'd like to store a future date in those 4 bytes. Is there a way to
convert a date to a 4 byte string?
>
When I do something like this,
>
string stringDate =
DateTime.Parse( "1/15/2210").ToBinary ().ToString("X" );
>
I get a hex # 15 characters long.
>
Any suggestions? I only have 4 bytes to work with to stay backward
compatible.
>
Thanks,
Steve
>

[Ignacio Machin \( .NET/ C# MVP \)]

Re: Date to 4 byte string

Hi Jon,


Nice catch :)

--
Ignacio Machin

http://www.laceupsolutions.com

Mobile & warehouse Solutions.
"Jon Skeet [C# MVP]" <skeet@pobox.co mwrote in message
news:MPG.219973 559c4994995ca@m snews.microsoft .com...

Steve <kilroy@harpser vices.comwrote:

>I have a registration code that currently has 4 bytes that are unused.
>I'd like to store a future date in those 4 bytes. Is there a way to
>convert a date to a 4 byte string?

>
One thing no-one else has mentioned: strings aren't comprised of bytes.
They're comprised of *characters*. Now, do you need a 4-byte data
structure of any description, or an actual 4 character string?
>
If you can use 4 bytes in an arbitrary fashion, using an int is likely
to be the best solution. 4 characters would be a different matter.
>
--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[Peter Duniho]

Re: Date to 4 byte string

On 2007-11-05 10:37:47 -0800, Jon Skeet [C# MVP] <skeet@pobox.co msaid:

Steve <kilroy@harpser vices.comwrote:

>I have a registration code that currently has 4 bytes that are unused.
>I'd like to store a future date in those 4 bytes. Is there a way to
>convert a date to a 4 byte string?

>
One thing no-one else has mentioned: strings aren't comprised of bytes.

That's true.

They're comprised of *characters*.

That's not. :) A string may _comprise_ characters. It's not
_comprised of_ characters, it's _composed of_ characters.

Sorry, pet peeve. But if people keep misusing "comprise" like that,
we're left with a word that used to be a perfectly useful word but
which is now just a useless synonym for "compose".

I hope your editor doesn't let you get away with stuff like that in
your book. :)

Now, do you need a 4-byte data
structure of any description, or an actual 4 character string?

Now that is a very good point. As is sometimes the case, I and others
have fallen into the trap of assuming the OP has asked a question that
correctly reflects what he really wants to do. But you're right, his
question is ambigious and he should clarify whether he has 4 bytes or 4
characters to use.

Interestingly, if the latter then my personal opinion is that his
options are possibly actually more restricted than if he had 4 bytes.
Though the native .NET String format is 2 bytes per character,
typically one would not want to store invalid characters or characters
that wouldn't be correctly represented in some external storage.

So unless he could guarantee the string (assuming it is really a
string) is stored as some Unicode format, he'd want to limit himself to
at least regular, printable 8-bit characters (e.g. the Windows "ANSI"
or similar), if not to the printable subset of 7-bit ASCII. That
significantly would reduce the possible number of combinations
available below what a regular 32-bit binary data value would allow.

Ah...nothing is ever as simple as it first looks. :)

Pete

[=?Utf-8?B?UGV0ZXIgQnJvbWJlcmcgW0MjIE1WUF0=?=]

Re: Date to 4 byte string

Jon, if this (below) converts back - and - forth:

int myDate = 20071105;
byte[] b = BitConverter.Ge tBytes(myDate);
Console.WriteLi ne(b.Length.ToS tring() + " bytes.");
// reads "4 bytes"
// And -back again:
Console.WriteLi ne("Orignal: " +BitConverter.T oInt32(b,
0).ToString());

-- then converting a dateTime object eg '11/05/2007' (US)
to the corresponding integer above is simple. Yes?
Peter
--

http://www.eggheadcafe.com

unBlog: http://petesbloggerama.blogspot.com
BlogMetaFinder: http://www.blogmetafinder.com



"Jon Skeet [C# MVP]" wrote:

Steve <kilroy@harpser vices.comwrote:

I have a registration code that currently has 4 bytes that are unused.
I'd like to store a future date in those 4 bytes. Is there a way to
convert a date to a 4 byte string?

>
One thing no-one else has mentioned: strings aren't comprised of bytes.
They're comprised of *characters*. Now, do you need a 4-byte data
structure of any description, or an actual 4 character string?
>
If you can use 4 bytes in an arbitrary fashion, using an int is likely
to be the best solution. 4 characters would be a different matter.
>
--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too
>

[Peter Duniho]

Re: Date to 4 byte string

On 2007-11-05 11:29:00 -0800, Peter Bromberg [C# MVP]
<pbromberg@yaho o.NoSpamMaam.co msaid:

Jon, if this (below) converts back - and - forth:
>
int myDate = 20071105;
byte[] b = BitConverter.Ge tBytes(myDate);
Console.WriteLi ne(b.Length.ToS tring() + " bytes.");
// reads "4 bytes"
// And -back again:
Console.WriteLi ne("Orignal: " +BitConverter.T oInt32(b,
0).ToString());
>
-- then converting a dateTime object eg '11/05/2007' (US)
to the corresponding integer above is simple. Yes?

Storing a date in a 32-bit value is simple regardless, whether you use
the encoding you've demonstrated or some other. That's not the point
of Jon's post. The question Jon raises is that it's possible that the
OP has 4 characters, not 4 bytes, in which to store the data.
Depending on how those characters are stored, the OP could have more
flexibility or less as compared to a 32-bit data field.

Of course, if it really is a 32-bit data field in which the OP can
store the data, then the character question is moot. But we don't know
whether that's the case or not, until the OP clarifies his scenario.

Pete

[Jon Skeet [C# MVP]]

Re: Date to 4 byte string

Peter Duniho <NpOeStPeAdM@Nn OwSlPiAnMk.comw rote:

They're comprised of *characters*.

>
That's not. :) A string may _comprise_ characters. It's not
_comprised of_ characters, it's _composed of_ characters.
>
Sorry, pet peeve. But if people keep misusing "comprise" like that,
we're left with a word that used to be a perfectly useful word but
which is now just a useless synonym for "compose".
>
I hope your editor doesn't let you get away with stuff like that in
your book. :)

That's what I get for posting with my son anxious to play a Lego City
game :)

Now, do you need a 4-byte data
structure of any description, or an actual 4 character string?

>
Now that is a very good point. As is sometimes the case, I and others
have fallen into the trap of assuming the OP has asked a question that
correctly reflects what he really wants to do. But you're right, his
question is ambigious and he should clarify whether he has 4 bytes or 4
characters to use.
>
Interestingly, if the latter then my personal opinion is that his
options are possibly actually more restricted than if he had 4 bytes.
Though the native .NET String format is 2 bytes per character,
typically one would not want to store invalid characters or characters
that wouldn't be correctly represented in some external storage.

Exactly. It's interesting that a larger storage option is more
restrictive. It really depends on what's going to happen to it.

--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[=?Utf-8?B?UGV0ZXIgQnJvbWJlcmcgW0MjIE1WUF0=?=]

Re: Date to 4 byte string

Yes, understood. When we look at the OP's code sample:

string stringDate =
DateTime.Parse( "1/15/2210").ToBinary ().ToString("X" );

-- he is looking for a way to get a string (even if a HEX string).

I believe it is reasonably clear that because he is using an overload of
"ToString" that means (to him) somehow a character in a string is equivalent
to a byte.
--

Storing a date in a 32-bit value is simple regardless, whether you use
the encoding you've demonstrated or some other. That's not the point
of Jon's post. The question Jon raises is that it's possible that the
OP has 4 characters, not 4 bytes, in which to store the data.
Depending on how those characters are stored, the OP could have more
flexibility or less as compared to a 32-bit data field.
>
Of course, if it really is a 32-bit data field in which the OP can
store the data, then the character question is moot. But we don't know
whether that's the case or not, until the OP clarifies his scenario.
>
Pete
>
>

[Steve]

Re: Date to 4 byte string

On Mon, 5 Nov 2007 18:37:47 -0000, Jon Skeet [C# MVP]
<skeet@pobox.co mwrote:

>Steve <kilroy@harpser vices.comwrote:

>I have a registration code that currently has 4 bytes that are unused.
>I'd like to store a future date in those 4 bytes. Is there a way to
>convert a date to a 4 byte string?

>
>One thing no-one else has mentioned: strings aren't comprised of bytes.
>They're comprised of *characters*. Now, do you need a 4-byte data
>structure of any description, or an actual 4 character string?
>
>If you can use 4 bytes in an arbitrary fashion, using an int is likely
>to be the best solution. 4 characters would be a different matter.

Sorry I wasn't more clear. In my original post, I did mean bytes, not
characters. However, I later found that I had made a mistake and I
was looking at 4 bits; not 4 bytes. I doubt very seriously if anyone
can think of a way to store a date in 4 bits. Still, thanks to
everyone for their suggestions.

The only option I can now see is to modify the structure of our
original registration code. So much for backward compatibility. :-(

Steve