nsresult rv = SetPixel(aDecoded, idx); if ((++aPos >= mBIH.width) || NS_FAILED(rv))
nsresult rv = SetPixel(aDecoded, idx, aColors); if ((++aPos >= aMaxWidth) || NS_FAILED(rv))
inline nsresult nsBMPDecoder::Set4BitPixel(PRUint8*& aDecoded, PRUint8 aData, PRUint32& aPos){    PRUint8 idx = aData >> 4;    nsresult rv = SetPixel(aDecoded, idx);    if ((++aPos >= mBIH.width) || NS_FAILED(rv))        return rv;    idx = aData & 0xF;    rv = SetPixel(aDecoded, idx);    ++aPos;    return rv;}