/// <summary>
/// Decompresses data. Uses <see cref="BrotliDecoder"/>.
/// </summary>
/// <returns>Decompressed data.</returns>
/// <param name="compressed">Compressed data.</param>
/// <exception cref="ArgumentException">Invalid data.</exception>
/// <exception cref="OutOfMemoryException"></exception>
public static unsafe byte[] BrotliDecompress(ReadOnlySpan <byte> compressed)
{
int n = checked (compressed.Length * 4 + 8000);
for (int i = 0; i < 3; i++)
{
if (n < 512_000)
{
n *= 2;
}
}
//print.it(compressed.Length, n, n/compressed.Length); //usually ~ 80 KB
for (; ; n = checked (n * 2))
{
byte *b = null;
try {
b = MemoryUtil.Alloc(n);
if (BrotliDecoder.TryDecompress(compressed, new(b, n), out int nw))
{
return(new Span <byte>(b, nw).ToArray());
}
if (nw == 0)
{
throw new ArgumentException("cannot decompress this data");
}
//print.it(n);
}
finally { MemoryUtil.Free(b); }
}
}
/// <summary>
/// Compresses data. Uses <see cref="BrotliEncoder"/>.
/// </summary>
/// <param name="data">Data. See also: <see cref="MemoryMarshal.AsBytes"/>, <see cref="CollectionsMarshal.AsSpan"/>.</param>
/// <param name="level">Compression level, 0 (no compression) to 11 (maximal compression). Default 6. Bigger levels don't make much smaller but can make much slower.</param>
/// <exception cref="ArgumentOutOfRangeException">Invalid <i>level</i>.</exception>
/// <exception cref="OutOfMemoryException"></exception>
public static unsafe byte[] BrotliCompress(ReadOnlySpan <byte> data, int level = 6)
{
int n = BrotliEncoder.GetMaxCompressedLength(data.Length);
var b = MemoryUtil.Alloc(n);
try {
if (!BrotliEncoder.TryCompress(data, new(b, n), out n, level, 22))
{
throw new AuException();
}
return(new Span <byte>(b, n).ToArray());
}
finally { MemoryUtil.Free(b); }
}