Custom File Reader

Question

Hello,

I'm going to read Mbox rd files, for example Google takeout, they are simply a collection of normal rfc-822 email files, the tip is that beginning of each email is:

From xxxvbLf

The starting line begins with From and one space, then some chars and finally a vbLf (not vbCrLf)

So it must begin with "From " and ends with vbLf, each email also ends with a blank line: vbCrLf

Using sr As New StreamReader(file, True)
While Not sr.EndOfStream
    sr.ReadLine
End While

I've no idea if StreamReader is the way to go, because its .ReadLine will not return the ending vbLf

The file can be huge so read all text at once is not an option, should be read message by message, and split by lines that start with From and ends with vbLf

Any tip on the correct algorithm is appreciated.

Thanks in advance :)

Answer 1

Hi @StewartBW ,

StreamReader.ReadLine() strips the line endings (vbCrLf, vbLf, or vbCr) before returning the line. Therefore, vbLf is no longer present in the returned string.

TextFieldParser does not support delimiters that contain end-of-line characters.

You can distinguish between mails by checking the blank line and the "From " in the next line.

Best Regards.

Jiachen Li

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Answer 2

Briefly, check if ReadLine returns a line that starts with “From ” .