Valid Characters

[preport]

I'm trying to ensure that all the characters in my XML document are
characters specified in this document:
http://www.w3.org/TR/2000/REC-xml-20001006#charsets

Would a function like this work:

private static string formatXMLString (string n)
{
if (string.IsNullO rEmpty(n)) return n;
System.Text.Str ingBuilder sb = new System.Text.Str ingBuilder();
char[] chrs = n.ToCharArray() ;
char c;
int x, j = chrs.Length;
for (x = 0; x < j; x++)
{
c = chrs[x];
if (c == 0x9 || c == 0xA || c == 0xD ||
(c 0x20 && c < 0xd7ff) ||
(c 0xe000 && c < 0xffd) ||
(c 0x10000 && c < 0x10ffff))
{
sb.Append(c);
}
}
return sb.ToString();
}

I've never compared characters to like this (0x9, 0xffd, etc...)?
I'm not trying to be lazy and not test it myself, I just don't know if this
type of character comparison is the correct logic for the results I'm
looking for.

Any input?

[preport]

Thank you.....I was aware of the tab, carriage return, and line feed....and
I did end up catching my "inclusive comparison" problem, but I did not know
what (U+FFFE) and U+10000-U+10FFFF.

Thank you.

[David Browne]

"Jon Skeet [C# MVP]" <sk***@pobox.co mwrote in message
news:MP******** *************** *@msnews.micros oft.com...

<"David Browne" <davidbaxterbro wne no potted me**@hotmail.co m>wrote:

<snip>

>Sure. Don't be lazy.

And a char is a 2-byte type, so your literals should all be 2-byte
literals,
and should be cast to char for comparison.

eg
char space = (char)0x0020;

While I agree that the "high order" comparisons are invalid, where do
you see the benefit in converting to char for comparison?

Just to remove implicit conversions from the code. The same reason I like
to see parentheses control order of operations instead of relying on
operator precedence. I think it makes the code more readable and less
fragile to have the the operations explicit.

David

[Jon Skeet [C# MVP]]

<"David Browne" <davidbaxterbro wne no potted me**@hotmail.co m>wrote:

While I agree that the "high order" comparisons are invalid, where do
you see the benefit in converting to char for comparison?

Just to remove implicit conversions from the code. The same reason I like
to see parentheses control order of operations instead of relying on
operator precedence. I think it makes the code more readable and less
fragile to have the the operations explicit.

In some cases I'd agree, but in this case I think it would make it
harder to read overall. Personal preference though...

--
Jon Skeet - <sk***@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

[Mihai N.]

Yes, but a surrogate will occupy two char's. A char is not a Unicode

character; it's an unsigned 16bit integer, and the range of a char is not
U+0000 to U+ffff, it's 0x0000 to 0xffff.

Yes.
Which means that the condition
(c 0x10000 && c < 0x10ffff))
has to be rewriten in terms of surrogates.
--
Mihai Nita [Microsoft MVP, Windows - SDK]
http://www.mihai-nita.net
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