/// <summary>Constructor</summary>
/// <param name="fin">FS input stream.</param>
/// <param name="fileLength">Length of the corresponding file</param>
/// <exception cref="System.IO.IOException"/>
public Reader(FSDataInputStream fin, long fileLength, Configuration conf)
{
this.@in = fin;
this.conf = conf;
// move the cursor to the beginning of the tail, containing: offset to the
// meta block index, version and magic
fin.Seek(fileLength - BCFile.Magic.Size() - Utils.Version.Size() - long.Size / byte
.Size);
long offsetIndexMeta = fin.ReadLong();
version = new Utils.Version(fin);
BCFile.Magic.ReadAndVerify(fin);
if (!version.CompatibleWith(BCFile.ApiVersion))
{
throw new RuntimeException("Incompatible BCFile fileBCFileVersion.");
}
// read meta index
fin.Seek(offsetIndexMeta);
metaIndex = new BCFile.MetaIndex(fin);
// read data:BCFile.index, the data block index
BCFile.Reader.BlockReader blockR = GetMetaBlock(BCFile.DataIndex.BlockName);
try
{
dataIndex = new BCFile.DataIndex(blockR);
}
finally
{
blockR.Close();
}
}
/// <summary>Constructor</summary>
/// <param name="fout">FS output stream.</param>
/// <param name="compressionName">
/// Name of the compression algorithm, which will be used for all
/// data blocks.
/// </param>
/// <exception cref="System.IO.IOException"/>
/// <seealso cref="Compression.GetSupportedAlgorithms()"/>
public Writer(FSDataOutputStream fout, string compressionName, Configuration conf
)
{
if (fout.GetPos() != 0)
{
throw new IOException("Output file not at zero offset.");
}
this.@out = fout;
this.conf = conf;
dataIndex = new BCFile.DataIndex(compressionName);
metaIndex = new BCFile.MetaIndex();
fsOutputBuffer = new BytesWritable();
BCFile.Magic.Write(fout);
}