/**
* Make a new Pico output stream, wrapping the provided stream. Use the given key to encrypt the
* data.
*
* @param key The key to use to encrypt.
* @param os The stream to get the output.
* @throws IOException An error occurred creating the temporary file.
*/
public PicoOutputStream(byte[] key, OutputStream os) throws IOException {
super(os);
if (key == null) {
throw new NullPointerException("The key is null.");
}
if (os == null) {
throw new NullPointerException("The output stream is null.");
}
_backing = os;
try {
_hash = MessageDigest.getInstance(PicoStructure.HASH);
} catch (NoSuchAlgorithmException nsae) {
throw new RuntimeException("Failed to create hash.", nsae);
}
// Construct a temporary file to get the encrypted data.
_tmpfile = File.createTempFile("pico", "pico");
_tmpfile.deleteOnExit();
_encrypted = new FileOutputStream(_tmpfile);
// Build the header.
_head = new PicoHeader();
_head.setKey(key);
}
/**
* Create a new Pico file instance from the given random access file. If the file exists and it is
* not empty then it is truncated. If it does not exist then it is created.
*
* @param backing The random access file.
* @param key The key to use to encrypt the file.
* @throws IOException The file cannot be read.
*/
protected PicoFile(RandomAccessFile backing, byte[] key) throws IOException {
assert backing != null : "Backing is null.";
assert key != null : "Key is null.";
assert key.length > 0 : "Key is missing.";
_backing = backing;
_open = true;
_resetDigest();
// We are creating a new file, so truncate any existing file and
// generate a new header.
_backing.setLength(0L);
_head = new PicoHeader();
_head.setKey(key);
// Now the Header size is fixed since we have the key and know the size
// of the hash
// we will write later.
// This actually positions us to _head.offset + 0
position(0L);
}
