C# Encode.<format>.GetBytes() returning different data to that input

Question

From the docs, Encode should provide a way to convert bytes to a string and back again. However, this test case gives very different results after the decode. The input data 'bytes' is 6 elements, but the output data 'outputData' is 17 elements. Why is this?

    byte[] bytes = new byte[] { 24, 48, 49, 127, 250, 255, 1 };

    char[] charData = Encoding.UTF7.GetChars(bytes);
    byte[] outputData = Encoding.UTF7.GetBytes(charData);

You use text encodings when you have arbitrary sets of characters and need to control their byte representations. Not for taking an arbitrary set of bytes and turning them into characters. You have a set of bytes that a UTF-7 encoding of characters would never produce. It's not surprising that you can't round trip them when trying to use it the wrong way around. — Damien_The_Unbeliever
– Damien_The_Unbeliever, Commented Feb 20, 2020 at 14:48
If you have an arbitrary set of bytes and need to round-trip them via strings, you should be looking for something that is designed to work that way around - e.g. Base-64 encoding. — Damien_The_Unbeliever
– Damien_The_Unbeliever, Commented Feb 20, 2020 at 14:51
UTF7Encoding does not provide error detection. When invalid bytes are encountered, UTF7Encoding generally emits the invalid bytes........, decoding with Encoding.UTF8.GetBytes(charData); shows this. — Luuk
– Luuk, Commented Feb 20, 2020 at 14:54

David Coombes · Accepted Answer · 2020-02-20 15:01:48Z

2

From Damien_The_Unbeliever's suggestion, found Convert instead

    byte[] bytes = new byte[] { 24, 48, 49, 127, 250, 255, 1 };

    // encode
    string byteString = Convert.ToBase64String(bytes);
    byte[] byteList = Convert.FromBase64String(byteString);

answered Feb 20, 2020 at 15:01

David Coombes

3171 silver badge13 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

C# Encode.<format>.GetBytes() returning different data to that input

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related