public static void Compress(Stream input, Stream output, BlockCompressionBuffer buffer)
{
if (!input.CanRead)
{
throw new ArgumentException("stream must be readable", nameof(input));
}
if (!output.CanWrite)
{
throw new ArgumentException("stream must be writable", nameof(output));
}
var inputBlock = buffer.Input;
var outputBlock = buffer.Output;
var blockSize = buffer.BlockSize;
var w = new BinaryWriter(output);
for (; ;)
{
int read = input.Read(inputBlock, 0, blockSize);
if (read == 0)
{
break;
}
int compressedSize = CompressBlock(inputBlock, outputBlock, read);
// todo: if compressedSize < blockSize-(2+13) else no compression
w.Write((ushort)compressedSize);
w.Write(outputBlock, 0, compressedSize);
if (read < blockSize)
{
break;
}
}
}
private static void Text()
{
var text = File.ReadAllText(@"..\..\text.txt");
//var text2 = File.ReadAllText(@"rand.txt");
var blockSizes = new int[] { 1 * 1024, 4 * 1024, 8 * 1024, 16 * 1024 };
Console.Write("N;uncompressed");
foreach (var blockSize in blockSizes)
{
Console.Write($";compressed{blockSize}");
}
foreach (var blockSize in blockSizes)
{
Console.Write($";ratio{blockSize}");
}
foreach (var blockSize in blockSizes)
{
Console.Write($";throughput{blockSize}");
}
Console.WriteLine();
for (int i = 1; i <= 16; i++)
{
var bytes = _encoding.GetBytes(text.Substring(0, i * 1024));
var output = new MemoryStream();
//var deflate = new DeflateStream(buffer, CompressionLevel.Optimal, true);
//var textWriter = new StreamWriter(deflate, _encoding);
//textWriter.Write(text);
//textWriter.Flush();
//deflate.Dispose();
var cols = new List <Tuple <int, int, double, double> >();
foreach (var blockSize in blockSizes)
{
var blockBuffer = new BlockCompressionBuffer(blockSize);
var input = new MemoryStream(bytes, false);
var sw = new Stopwatch();
int n;
for (n = 0; n < 1000; n++)
{
// reset
input.Position = 0;
output.Position = 0;
output.SetLength(0);
sw.Start();
BlockCompression.Compress(input, output, blockBuffer);
sw.Stop();
}
var t = bytes.Length / sw.Elapsed.TotalSeconds; // Kbytes / s
var uncompressedSize = bytes.Length;
var compressedSize = (int)output.Length;
var ratio = compressedSize / (double)uncompressedSize;
cols.Add(Tuple.Create(uncompressedSize, compressedSize, ratio, sw.Elapsed.TotalSeconds)); // actually milliseconds
}
Console.Write($"{i};{cols[0].Item1}");
foreach (var col in cols)
{
Console.Write($";{col.Item2}");
}
foreach (var col in cols)
{
Console.Write($";{col.Item3:0.00}");
}
foreach (var col in cols)
{
Console.Write($";{col.Item4:0.00}");
}
Console.WriteLine();
}
}
