CODEWITHSUNDEEP
javastringbytedata-conversion
dcrearer
dcrearer

Reputation: 2072

Prevent sign-extension during byte array to string conversion

The BYTEMASK flag in the sample code keeps the value from being signed-extended when it's converted to an int. How is this flag preventing the conversion form being sign-extended?

private final static int BYTEMASK = 0xFF;

private static String byteArrayToDecimalString(byte[] bArray) {
        StringBuilder rtn = new StringBuilder();
        for(byte b : bArray) 
            rtn.append(b & BYTEMASK).append(" ");
        return rtn.toString();
    }

Upvotes: 0

Views: 108

Answers (1)

Henry
Henry

Reputation: 43758

As others have already mentioned in comments, the bytemask does not prevent the sign extension, instead it undoes it. For example:

0x80 -- sign extend -> 0xffffff80 -- mask with 0xff -> 0x00000080

Upvotes: 1

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