import "Stream"

importJava "java.io.InputStream" where
    """Reads bytes from the stream to a mutable vector. The maximum number of bytes read is the dimension of the vector. Returns the actual number of bytes read or -1, if the stream has finished."""
    @JavaName read
    readBytesM :: InputStream -> MVector Byte -> <Proc> Integer

    """Reads a range of bytes from the stream to a mutable vector. The first integer is the  offset the second integer is the  maximum length of the range. Returns the actual number of bytes read or -1, if the stream has finished."""
    @JavaName read
    readRangeOfBytesM :: InputStream -> MVector Byte -> Integer -> Integer -> <Proc> Integer

"""Reads bytes from the stream. The integer parameter is the maximum number of bytes. Returns Nothing if stream has finished or a vector of bytes read."""
readBytes :: InputStream -> Integer -> <Proc> Maybe (Vector Byte)
readBytes stream length = 
    if count == (-1)
    then Nothing
    else if count == length
    then Just (freezeMVector result)
    else Just (take count (freezeMVector result)) 
  where
    result = createMVector length
    count = readBytesM stream result 

importJava "java.io.OutputStream" where
    """Writes given vector of bytes to output stream."""
    @JavaName write
    writeBytes :: OutputStream -> Vector Byte -> <Proc> ()

    @JavaName write
    writeBytesM :: OutputStream -> MVector Byte -> <Proc> ()
    
    """Writes a range of bytes from the vector to output stream. The first integer is the offset the second integer is the length of the range."""
    @JavaName write
    writeRangeOfBytes :: OutputStream -> Vector Byte -> Integer -> Integer -> <Proc> ()
    
    @JavaName write
    writeRangeOfBytesM :: OutputStream -> MVector Byte -> Integer -> Integer -> <Proc> ()
    
"""Copy all available bytes from output stream to input stream."""
copyAllBytes :: OutputStream -> InputStream -> <Proc> ()
copyAllBytes output input = loop ()
  where
    buffer = createMVector 4096
    loop () = let count = readBytesM input buffer
              in if count == (-1) 
                 then ()
                 else do
                     writeRangeOfBytesM output buffer 0 count
                     loop ()