import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

public class SignedToUnsigned
{
    public SignedToUnsigned(String srcImgName, String tgtImgName)
    {
	try {
	    byte[] srcBuffer = new byte[4096];
	    byte[] tgtBuffer = new byte[4096];

	    // Source data
	    File srcImgFile = new File(srcImgName);
	    FileInputStream srcImgStream = new FileInputStream(srcImgFile);
	    long srcDataSize = srcImgFile.length();

	    // Target data
	    File tgtImgFile = new File(tgtImgName);
	    FileOutputStream tgtImgStream = new FileOutputStream(tgtImgFile);

	    // Read data into the buffer until the end of the source file
	    long totalBytesRead = 0;
	    while (totalBytesRead < srcDataSize) {

		// Read source data into the buffer
		int bytesRead = (int)srcImgStream.read(srcBuffer);
		totalBytesRead += bytesRead;

		// Convert signed shorts to unsigned shorts
		for (int i = 0; i < bytesRead; i+=2) {
		    byte b1 = srcBuffer[i];
		    byte b2 = srcBuffer[i+1];

		    int s = (b1 << 8) + (b2 << 0);

		    // Map (-32768,32767) to (0,32767)
		    s = (s + 32768)/2;

		    tgtBuffer[i] = (byte)((s >>> 8) & 0xFF);
		    tgtBuffer[i+1] = (byte)(s & 0xFF);
		}

		// Write the target data to the new file
		tgtImgStream.write(tgtBuffer, 0, bytesRead);
	    }

	    // Close
	    tgtImgStream.flush();
	    tgtImgStream.close();
	}

	catch (Exception e) { e.printStackTrace(); }
    }

    public static void main(String[] args) 
    {
	SignedToUnsigned stu = new SignedToUnsigned(args[0], args[1]);
    }
}