private static void BlockStreamWriterOnceTest(IBlockTransformer transformer, IBlockCache cache)
{
using var ms = new KeepOpenMemoryStream();
const int COUNT = 100_000;
long expectedLength;
using (var writer = new BlockWriteOnceStream(ms, transformer)) {
using var binaryWriter = new BinaryWriter(writer, Encoding.ASCII, true);
for (var i = 0; i < COUNT; ++i)
{
binaryWriter.Write(i);
}
writer.Write(new byte[1 << 22]);
expectedLength = writer.Length;
}
using (var writer = new BlockReadOnlyStream(ms, transformer, cache: cache)) {
Assert.AreEqual(expectedLength, writer.Length);
using var binaryReader = new BinaryReader(writer, Encoding.ASCII, true);
using var binaryCursorReader = new BinaryReader(writer.CreateCursor(), Encoding.ASCII, true);
for (var i = 0; i < COUNT; ++i)
{
Assert.AreEqual(i, binaryReader.ReadInt32());
Assert.AreEqual(i, binaryCursorReader.ReadInt32());
}
var buf = new byte[1 << 22];
Assert.AreEqual(buf.Length, writer.Read(buf));
Assert.IsTrue(buf.All(i => i == 0));
}
}
public Index(BlockReadOnlyStream stream)
{
using var reader = stream.CreateCursor();
reader.Seek(-sizeof(long), SeekOrigin.End);
var headerLen = reader.ReadInt64();
var headerBytes = new byte[headerLen];
var headerOffset = reader.Seek(-sizeof(long) - headerBytes.Length, SeekOrigin.End);
reader.ReadFullBlock(headerBytes);
using var header = new MemoryStream(headerBytes, false);
var blen = header.ReadInt32();
var binit = new byte[blen];
header.ReadFullBlock(binit);
Filter = new BloomFilter(binit);
var len = header.ReadInt32();
var idx = new List <KeyValuePair <byte[], long> >();
for (var i = 0; i < len; ++i)
{
var logicalOffset = header.ReadInt32();
var klen = header.ReadInt32();
var key = new byte[klen];
header.ReadFullBlock(key);
var absOffset = headerOffset - logicalOffset;
idx.Add(new KeyValuePair <byte[], long>(key, absOffset));
}
Indexes = idx.ToArray();
{
var firstIndex = Indexes.First();
reader.Seek(firstIndex.Value, SeekOrigin.Begin);
var items = reader.ReadInt32();
reader.ReadInt64();
var blengths = new byte[items * sizeof(int) * 2];
reader.ReadFullBlock(blengths);
var lengths = blengths.AsSpan();
var klen = BinaryPrimitives.ReadInt32LittleEndian(lengths);
FirstKey = reader.ReadFullBlock(klen);
}
LastKey = Indexes[Indexes.Length - 1].Key;
}