Decoding Run Length Encoded String

Question

I have a class that reads data from a server using a BufferedReader. The data is read into a char[]. This data has been Run Length Encoded by a seperate process.
I loop through the char[] looking for a sentinal value. Once this value is found, I look at the next char to find the length and then the next char to find the value that needs to be populated.
In order to correctly determine the length, I & the char with 0xff. This works most of the time. What I am seeing is that in certain circumstances the value is not what I expect. For example, in the following hex representation:
F0 8B 20
FO is my sentinel. 8B tells me to pad for 139. And, 20 tells me the value is a Space. So my class should at this point add 139 spaces.
However, even though I & the char with 0xff it interprets the decimal value as 57.
Here is the Method that does the UnRLE:
public static CharArrayWriter UnRle(char[] InBuffer)
        try {
            CharArrayWriter caWriter = new CharArrayWriter();
            if (IsRle(InBuffer)) {
                int iLoop = 0, iByteRepeat = 0;
                for (int iIdx = RLE_HEADER.length() + RLE_SENTINEL_LEN; iIdx < InBuffer.length; iIdx++) {     // Start after header
                    if (InBuffer[iIdx] == RLE_SENTINEL) {
                        if (InBuffer[iIdx + 1] == RLE_SENTINEL)                           
                            caWriter.write(RLE_SENTINEL);
                        else {                       
                            for (iLoop = 0; iLoop < (int)InBuffer[iIdx + 1] & 0xff; iLoop++)
                                caWriter.write(InBuffer[iIdx + 2]);
                            iIdx += 2;
                    else
                        caWriter.write(InBuffer[iIdx]);
            else
                caWriter.write(InBuffer);
            return caWriter;
        catch (Exception e) {
            System.err.println("UnRle Exception " + e.toString());
            return null;
    }Any ideas?
Thanks,
ABumgardner

Answer 1

Readers and Writers expect to deal with 16-bit characters. You need to be using InputStream and OutputStream.