/// <exception cref="System.IO.IOException"></exception>
public virtual CodecHandler CreateHandler(PageChannel channel, Encoding charset)
{
JetFormat format = channel.GetFormat();
switch (format.CODEC_TYPE)
{
case JetFormat.CodecType.NONE:
{
// no encoding, all good
return(DefaultCodecProvider.DUMMY_HANDLER);
}
case JetFormat.CodecType.JET:
{
return(JetCryptCodecHandler.Create(channel));
}
case JetFormat.CodecType.MSISAM:
{
return(MSISAMCryptCodecHandler.Create(GetPassword(), channel, charset));
}
default:
{
throw new RuntimeException("Unknown codec type " + format.CODEC_TYPE);
}
}
}
/// <summary>
/// <inheritDoc></inheritDoc>
/// <p>
/// This implementation returns DUMMY_HANDLER for databases with no encoding
/// and UNSUPPORTED_HANDLER for databases with any encoding.
/// </summary>
/// <exception cref="System.IO.IOException"></exception>
public virtual CodecHandler CreateHandler(PageChannel channel, Encoding charset)
{
JetFormat format = channel.GetFormat();
switch (format.CODEC_TYPE)
{
case JetFormat.CodecType.NONE:
{
// no encoding, all good
return(DUMMY_HANDLER);
}
case JetFormat.CodecType.JET:
{
// check for an encode key. if 0, not encoded
ByteBuffer bb = channel.CreatePageBuffer();
channel.ReadPage(bb, 0);
int codecKey = bb.GetInt(format.OFFSET_ENCODING_KEY);
return((codecKey == 0) ? DUMMY_HANDLER : UNSUPPORTED_HANDLER);
}
case JetFormat.CodecType.MSISAM:
{
// always encoded, we don't handle it
return(UNSUPPORTED_HANDLER);
}
default:
{
throw new RuntimeException("Unknown codec type " + format.CODEC_TYPE);
}
}
}
/// <exception cref="System.IO.IOException"></exception>
public static CodecHandler Create(string password, PageChannel channel, Encoding
charset)
{
ByteBuffer buffer = ReadHeaderPage(channel);
if ((buffer.Get(ENCRYPTION_FLAGS_OFFSET) & NEW_ENCRYPTION) != 0)
{
return(new HealthMarketScience.Jackcess.MSISAMCryptCodecHandler(password, charset
, buffer));
}
// old MSISAM dbs use jet-style encryption w/ a different key
return(new _JetCryptCodecHandler_87(GetOldDecryptionKey(buffer, channel.GetFormat
())));
}
/// <exception cref="System.IO.IOException"></exception>
public static CodecHandler Create(PageChannel channel)
{
ByteBuffer buffer = ReadHeaderPage(channel);
JetFormat format = channel.GetFormat();
byte[] encodingKey = new byte[ENCODING_KEY_LENGTH];
buffer.Position(format.OFFSET_ENCODING_KEY);
buffer.Get(encodingKey);
bool clearData = true;
foreach (byte byteVal in encodingKey)
{
if (byteVal != 0)
{
clearData = false;
}
}
return(clearData ? DefaultCodecProvider.DUMMY_HANDLER : new HealthMarketScience.Jackcess.JetCryptCodecHandler
(encodingKey));
}
/// <summary>
/// Returns a ByteBuffer of at least the defined page size, with the limit
/// set to the page size, and the predefined byteOrder.
/// </summary>
/// <remarks>
/// Returns a ByteBuffer of at least the defined page size, with the limit
/// set to the page size, and the predefined byteOrder. Will be rewound iff
/// autoRewind is enabled for this buffer.
/// </remarks>
public ByteBuffer GetPageBuffer(PageChannel pageChannel)
{
return(GetBuffer(pageChannel, pageChannel.GetFormat().PAGE_SIZE));
}
