public void VerifyCompression_LargeCorpus()
{
var stream = new MemoryStream();
var writer = new BitStreamWriter(stream, true);
var reader = new BitStreamReader(stream, true);
string input = TestResources.RFC5_Text;
var state = new TreeStateStore();
var compressor = new StaticHuffman <char>(CharacterFrequencies(input));
compressor.WriteTable(state.WriteSymbol, state.WriteUInt32);
foreach (char ch in input)
{
compressor.WriteCode(ch, writer.Write);
}
writer.Flush();
state.Reset();
var decompressor = new StaticHuffman <char>(state.ReadSymbol, state.ReadUInt32);
stream.Position = 0;
foreach (char ch in input)
{
Assert.AreEqual(ch, decompressor.GetSymbol(reader.ReadBoolean));
}
}
public void Should_WriteUe()
{
var stream = new BitStream();
var writer = new BitStreamWriter(stream);
var val = 6300U;
var bitsWritten = writer.WriteUe(val);
writer.Flush();
Assert.AreEqual(24, bitsWritten);
var bytes = stream.ToArray();
Assert.AreEqual(new byte[] { 0, 24, 185 }, bytes);
}
public void Should_WriteInt48()
{
var stream = new BitStream();
var writer = new BitStreamWriter(stream);
var val = Int48.MaxValue;
writer.Write(val);
writer.Flush();
Assert.AreEqual(6, stream.Length);
var bytes = stream.ToArray();
var valBits = val.GetBits();
var byteBits = bytes.GetBits(Int48.BitSize);
CollectionAssert.AreEqual(valBits, byteBits);
}
public void Should_WriteBit()
{
var stream = new BitStream();
var writer = new BitStreamWriter(stream);
writer.WriteBit(0);
writer.WriteBit(1);
writer.WriteBit(true);
writer.WriteBit(new Bit(1));
writer.Flush();
Assert.AreEqual(1, stream.Length);
var bytes = stream.ToArray();
// we wrote 0111 binary, which is 14
Assert.AreEqual(14, bytes[0]);
}
public void Should_WriteBitsAndBytes()
{
var stream = new BitStream();
stream.AllowUnalignedOperations = true;
var writer = new BitStreamWriter(stream);
var val = new byte[] { 0xFF, 0x01, 0xCC, 0xAA };
writer.WriteBit(0);
writer.WriteBit(1);
writer.Write(val);
writer.Flush();
Assert.AreEqual(val.Length + 1, stream.Length);
var bytes = stream.ToArray();
CollectionAssert.AreNotEqual(val, bytes);
CollectionAssert.AreEqual(new byte[] { 254, 7, 48, 171, 2 }, bytes);
}
public void leaveOpen_False()
{
var stream = new MemoryStream();
using (var writer = new BitStreamWriter(stream, false))
{
Assert.AreEqual(false, writer.CanRead);
Assert.AreEqual(true, writer.CanWrite);
Assert.AreEqual(true, writer.CanSeek);
Assert.AreEqual(0, writer.Length);
Assert.AreEqual(0, writer.BitLength);
Assert.AreEqual(0, writer.BitPosition);
Assert.AreEqual(0, writer.Position);
writer.Write(true);
Assert.AreEqual(1, writer.Length);
Assert.AreEqual(1, writer.BitLength);
Assert.AreEqual(1, writer.BitPosition);
Assert.AreEqual(0, writer.Position);
writer.Seek(0, SeekOrigin.Begin);
Assert.AreEqual(1, stream.Length);
Assert.AreEqual(0, stream.Position);
Assert.AreEqual(0x80, stream.GetBuffer()[0]);
writer.Write(false);
}
Assert.AreEqual(1, stream.Length);
Assert.AreEqual(1, stream.Position);
Assert.AreEqual(0, stream.GetBuffer()[0]);
using (var writer = new BitStreamWriter(stream, false))
{
var data = new byte[] { 0x3c, 0x4b, 0x1a, 0x54, 0x22, 0x10, 0xaf, 0x89, 0x97, 0x65 };
writer.Write(data, 0, data.Length);
writer.Flush();
Assert.AreEqual(11, stream.Length);
Assert.AreEqual(11, stream.Position);
}
}
public static byte[] Encode(byte[] aData)
{
using (MemoryStream data = new MemoryStream())
{
BitStreamWriter writer = new BitStreamWriter(data);
var leaves = Analyze(aData);
var tree = GenerateTree(leaves);
tree.Serialize(writer);
WriteDynamicLength(writer, (ulong)aData.LongLength);
var lookup = GenerateLookup(leaves);
for (int i = 0; i < aData.Length; i++)
{
var n = lookup[aData[i]];
writer.WriteBits(n.bitPattern, n.bitCount);
}
writer.Flush();
return(data.ToArray());
}
}
public void VerifyCompression_astrachan_()
{
var stream = new MemoryStream();
string input = "astrachan_";
var compressor = new StaticHuffman <char>(CharacterFrequencies(input));
// Node ids: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
// Weights: 1 1 1 1 1 1 1 3 2 2 2 3 4 6 10
var state = new TreeState(8, '_', 'c', 'h', 'n', 'r', 's', 't', 'a', 0, 1, 2, 3, 4, 5, 6, 8, 9, 10, 7, 11,
12, 13);
compressor.WriteTable(state.WriteSymbol, state.WriteUInt32);
state.Final();
var writer = new BitStreamWriter(stream, true);
foreach (char ch in input)
{
compressor.WriteCode(ch, writer.Write);
}
writer.Flush();
state.Reset();
var decompressor = new StaticHuffman <char>(state.ReadSymbol, state.ReadUInt32);
state.Final();
state.Reset();
decompressor.WriteTable(state.WriteSymbol, state.WriteUInt32);
state.Final();
stream.Position = 0;
var reader = new BitStreamReader(stream, true);
foreach (char ch in input)
{
Assert.AreEqual(ch, decompressor.GetSymbol(reader.ReadBoolean));
}
}