Question

I have a data stream that may contain \r, \n, \r\n, \n\r or any combination of them. Is there a simple way to normalize the data to make all of them simply become \r\n pairs to make display more consistent?

So something that would yield this kind of translation table:

\r     --> \r\n \n     --> \r\n \n\n   --> \r\n\r\n \n\r   --> \r\n \r\n   --> \r\n \r\n\n --> \r\n\r\n 

Answer 1

I believe this will do what you need:

using System.Text.RegularExpressions; // ... string normalized = Regex.Replace(originalString, @"\r\n|\n\r|\n|\r", "\r\n"); 

I’m not 100% sure on the exact syntax, and I don’t have a .Net compiler handy to check. I wrote it in perl, and converted it into (hopefully correct) C#. The only real trick is to match "\r\n" and "\n\r" first.

To apply it to an entire stream, just run it on chunks of input. (You could do this with a stream wrapper if you want.)

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The original perl:

$str =~ s/\r\n|\n\r|\n|\r/\r\n/g; 

The test results:

[bash$] ./test.pl \r -> \r\n \n -> \r\n \n\n -> \r\n\r\n \n\r -> \r\n \r\n -> \r\n \r\n\n -> \r\n\r\n 

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Update: Now converts \n\r to \r\n, though I wouldn’t call that normalization.