How to concatenate strings that contains has nulls?

[jt]

I can't seem to find a way to concatenate strings that have nulls within the
string.

I have a string that I need another string that has nulls in it and what to
append
the 2nd string, 3 string and so forth to the 1st string.

Any ideas how to go about this?

Thanks,
jt

[Keith Thompson]

"jt" <jt****@hotmail .com> writes:

I can't seem to find a way to concatenate strings that have nulls
within the string.

I have a string that I need another string that has nulls in it and
what to append the 2nd string, 3 string and so forth to the 1st
string.

Any ideas how to go about this?

It's logically impossible. A "string" is, by definition, "a
contiguous sequence of characters terminated by and including the
first null character" (C99 7.1.1p1). If a sequence of characters
includes a null character other than at the end, it's not a string.

Since strcat() works with strings, it can't work with the sequences
you're using (as I'm sure you've discovered.

Since you don't have the trailing '\0' to mark the end of your
sequence, you have to have some other way of specifying how long it
is. Once you've done that, you can probably use memcpy() (or
memmove() if there's a possibility of overlap) to copy things around.
The required arguments to memcpy() are determined by the lengths of
the sequences you want to copy. Since you haven't told us how that's
defined, we can't provide more details.

Of course, you still have the same memory allocation issues (making
sure the target is big enough to hold the concatentated result) that
you have with real strings.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Mike Wahler]

"jt" <jt****@hotmail .com> wrote in message
news:h1******** ***********@tor nado.tampabay.r r.com...

I can't seem to find a way to concatenate strings that have nulls within
the string.
Of course not. By definition, a string cannot contain
embedded null characters. The null character ('\0')
is used to denote the end of a string.

I have a string that I need another string that has nulls in it and what
to append
the 2nd string, 3 string and so forth to the 1st string.

Any ideas how to go about this?

Stop thinking of them as strings. They're simply arrays
of characters. Then look up 'memcpy()' and 'memmove()'.
(Observe the notations in the documentation about overlapping
areas of memory).

-Mike

[Gordon Burditt]

>I can't seem to find a way to concatenate strings that have nulls within the

string.
If it has nulls internal to it, it's *NOT* a string.
How do you find the end or length of such a non-string?

I have a string
No, you don't. It's NOT a string!
that I need another string
Another *NON*-string!
that has nulls in it and what to
append
the 2nd string, 3 string and so forth to the 1st string.
They AREN'T STRINGS!!
Any ideas how to go about this?

Assuming:
You have as many ByteSequences ByteSequence1, ByteSequence2, ...
as you need, of length ByteSequence1Le ngth, ByteSequence2Le ngth, ...
and that there is sufficient storage at the end of ByteSequence1 to
hold the rest of them:

memcpy(ByteSequ ence1+ByteSeque nce1Length, ByteSequence2, ByteSequence2Le ngth);
memcpy(ByteSequ ence1+ByteSeque nce1Length+Byte Sequence2Length ,
ByteSequence3, ByteSequence3Le ngth);
memcpy(ByteSequ ence1+ByteSeque nce1Length+Byte Sequence2Length +ByteSequence3L ength,
ByteSequence4, ByteSequence4Le ngth);
...

NewByteSequence 1Length = ByteSequence1Le ngth + ByteSequence2Le ngth + ... ;
Gordon L. Burditt

[Christopher Benson-Manica]

Keith Thompson <ks***@mib.or g> wrote:

It's logically impossible. A "string" is, by definition, "a
contiguous sequence of characters terminated by and including the
first null character" (C99 7.1.1p1). If a sequence of characters
includes a null character other than at the end, it's not a string.

But it would be acceptable to refer to the array OP mentioned as a
series of contiguous strings, would it not? The sequence as a whole
is not a string, but the subsequences are, yes?

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.

[Gordon Burditt]

>> It's logically impossible. A "string" is, by definition, "a

contiguous sequence of characters terminated by and including the
first null character" (C99 7.1.1p1). If a sequence of characters
includes a null character other than at the end, it's not a string.

But it would be acceptable to refer to the array OP mentioned as a
series of contiguous strings, would it not? The sequence as a whole
is not a string, but the subsequences are, yes?

But you still have no way to figure out when you've reached the
LAST one. And you don't know whether the last \0 is part of
the non-string.

Gordon L. Burditt

[James McIninch]

jt wrote:

I can't seem to find a way to concatenate strings that have nulls within
the string.
This is impossible. By definition, a null marks the end of a string. You
can't have nulls within a string.

Perhaps you are thinking not of a string, but an array of characters of
known length.

I have a string that I need another string that has nulls in it and what
to append
the 2nd string, 3 string and so forth to the 1st string.
To concatenate two arrays, use memcpy()


Any ideas how to go about this?

Thanks,
jt

--
Remove '.nospam' from e-mail address to reply by e-mail

[Martin Ambuhl]

jt wrote:

I can't seem to find a way to concatenate strings that have nulls within the
string.

Your problem is meaningless. A null terminates a string. There is no
such thing as nulls within a string.

[Keith Thompson]

Christopher Benson-Manica <at***@nospam.c yberspace.org> writes:

Keith Thompson <ks***@mib.or g> wrote:

It's logically impossible. A "string" is, by definition, "a
contiguous sequence of characters terminated by and including the
first null character" (C99 7.1.1p1). If a sequence of characters
includes a null character other than at the end, it's not a string.

But it would be acceptable to refer to the array OP mentioned as a
series of contiguous strings, would it not? The sequence as a whole
is not a string, but the subsequences are, yes?

Only if the last character of the array happens to be a '\0';
otherwise it's a series of contiguous strings followed by an
unterminated character array.

In any case, that's probably not a useful way to look at it. They
seem to be just character arrays with '\0' being an ordinary value
with no special significance.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[jt]

"Martin Ambuhl" <ma*****@earthl ink.net> wrote in message
news:9f******** ********@newsre ad3.news.atl.ea rthlink.net...

jt wrote:

I can't seem to find a way to concatenate strings that have nulls within
the string.

Your problem is meaningless. A null terminates a string. There is no
such thing as nulls within a string.

True, a null terminates a string. But, what if that string happen to be a
binary file?