Remove ZLib APIs (#2262)

This code is not being called by ML.NET, and it was not intended to be public API. Removing.

Fix #2249

Author: eerhardt

src/Microsoft.ML.Data/DataLoadSave/Binary/CompressionKind.cs

@@ -2,11 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
 using System.IO;
 using System.IO.Compression;
-using Microsoft.ML.CommandLine;
-using Microsoft.ML.Data.IO.Zlib;
 using Microsoft.ML.Internal.Utilities;
 
 namespace Microsoft.ML.Data.IO
@@ -65,107 +62,4 @@ public static Stream DecompressStream(this CompressionKind compression, Stream s
             }
         }
     }
-
-    /// <summary>
-    /// A loadable class to parameterize compression.
-    /// </summary>
-    public abstract class Compression
-    {
-        public abstract CompressionKind Kind { get; }
-
-        /// <summary>
-        /// Generate an appropriate wrapping compressing stream for the codec. This
-        /// stream will be closable and disposable, without closing or disposing of
-        /// the passed in stream. The scheme for compression is parameterized by the
-        /// <see cref="Compression"/> instance.
-        /// </summary>
-        /// <param name="stream">The stream to which compressed data will be written</param>
-        /// <returns>A stream to which the user can write uncompressed data</returns>
-        public virtual Stream Open(Stream stream)
-        {
-            return Kind.CompressStream(stream);
-        }
-
-        // Named with "Impl" suffix since otherwise it was difficult to disambiguate
-        // with other identifiers.
-        public sealed class NoneImpl : Compression
-        {
-            public override CompressionKind Kind { get { return CompressionKind.None; } }
-        }
-
-        public sealed class ZlibImpl : Compression
-        {
-            public abstract class ArgumentsBase
-            {
-                [Argument(ArgumentType.AtMostOnce, HelpText = "Level of compression from 0 to 9", ShortName = "c")]
-
-                public int? CompressionLevel = 9;
-
-                [Argument(ArgumentType.AtMostOnce, HelpText = "Window bits from 8 to 15, higher values enable more useful run length encodings", ShortName = "w")]
-                public int WindowBits = 15;
-
-                [Argument(ArgumentType.AtMostOnce, HelpText = "Level of memory from 1 to 9, with higher values using more memory but enabling better, faster compression", ShortName = "m")]
-                public int MemoryLevel = 9;
-
-                [Argument(ArgumentType.AtMostOnce, HelpText = "Compression strategy to employ", ShortName = "s")]
-                public Constants.Strategy Strategy = Constants.Strategy.DefaultStrategy;
-            }
-
-            public sealed class DeflateArguments : ArgumentsBase
-            {
-            }
-
-            public sealed class ZlibArguments : ArgumentsBase
-            {
-            }
-
-            public override CompressionKind Kind
-            {
-                get { return CompressionKind.Deflate; }
-            }
-
-            private readonly int _windowBits;
-            private readonly Constants.Level _level;
-            private readonly bool _isDeflate;
-            private readonly int _memoryLevel;
-            private readonly Constants.Strategy _strategy;
-
-            private ZlibImpl(ArgumentsBase args, bool isDeflate)
-            {
-                Contracts.CheckUserArg(args.CompressionLevel == null ||
-                          (0 <= args.CompressionLevel && args.CompressionLevel <= 9),
-                          nameof(args.CompressionLevel), "Must be in range 0 to 9 or null");
-                Contracts.CheckUserArg(8 <= args.WindowBits && args.WindowBits <= 15, nameof(args.WindowBits), "Must be in range 8 to 15");
-                Contracts.CheckUserArg(1 <= args.MemoryLevel && args.MemoryLevel <= 9, nameof(args.MemoryLevel), "Must be in range 1 to 9");
-                Contracts.CheckUserArg(Enum.IsDefined(typeof(Constants.Strategy), args.Strategy), nameof(args.Strategy), "Value was not defined");
-
-                if (args.CompressionLevel == null)
-                    _level = Constants.Level.DefaultCompression;
-                else
-                    _level = (Constants.Level)args.CompressionLevel;
-                Contracts.Assert(Enum.IsDefined(typeof(Constants.Level), _level));
-                _windowBits = args.WindowBits;
-                _isDeflate = isDeflate;
-                _memoryLevel = args.MemoryLevel;
-                _strategy = args.Strategy;
-            }
-
-            public ZlibImpl(DeflateArguments args)
-                : this(args, isDeflate: true)
-            {
-                Contracts.Assert(Kind == CompressionKind.Deflate);
-            }
-
-            public ZlibImpl(ZlibArguments args)
-                : this(args, isDeflate: false)
-            {
-               // Contracts.Assert(Kind == CompressionKind.Zlib);
-            }
-
-            public override Stream Open(Stream stream)
-            {
-                return new ZDeflateStream(stream, _level, _strategy, _memoryLevel, !_isDeflate, _windowBits);
-            }
-        }
-    }
 }