mORMot Open Source

using System;
using System.Text;
using LibDeflate;
using System.Buffers;
...
    //-------------------------------------------------------------------------
    //| Decompress zlib string                                                |
    //-------------------------------------------------------------------------
    public static string DecompressString(string base64Data) {
      //Input                                                                 '
      byte[] compressedData = Convert.FromBase64String(base64Data);
      //Get original length                                                   '
      int uncompressedLength = BitConverter.ToInt32(compressedData, 0);
      //Input span                                                            '
      Span<byte> inputSpan = compressedData.AsSpan(12);
      //Output span                                                           '
      byte[] decompressedData = new byte[uncompressedLength];
      Span<byte> outputSpan = new Span<byte>(decompressedData);
      //Decompressing                                                         '
      using(Decompressor decompressor = new DeflateDecompressor()) {
        OperationStatus status = decompressor.Decompress(inputSpan, outputSpan, out int decompressSize);
        if(status != OperationStatus.Done) { throw new Exception(status.ToString()); }
        if(decompressSize != uncompressedLength) { throw new Exception("Decompress size error"); }
      }
      //Return                                                                '
      return Encoding.UTF8.GetString(outputSpan.ToArray());
    }