Attempt to use native zlib for gzip. Need lower level access

src/SharpCompress/Compressors/Deflate/GZipStream.NetStandard13.cs

@@ -0,0 +1,525 @@
+#if NETSTANDARD1_3
+using System;
+using System.Collections.Generic;
+using System.IO;
+using SharpCompress.Common;
+using SharpCompress.Converters;
+
+namespace SharpCompress.Compressors.Deflate
+{
+    public class GZipStream : Stream
+    {
+        private enum Mode
+        {
+            Unknown,
+            Reader,
+            Writer
+        }
+
+        internal static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+
+        public DateTime? LastModified { get; set; }
+        private byte[] _buf1 = new byte[1];
+        
+        private System.IO.Compression.DeflateStream BaseStream;
+        private bool disposed;
+        private Mode mode;
+
+
+        private string _GzipFileName;
+        private string _GzipComment;
+        private DateTime _GzipMtime;
+        private int _gzipHeaderByteCount;
+
+        public GZipStream(Stream stream, CompressionMode mode)
+            : this(stream, mode, CompressionLevel.Default, false)
+        {
+        }
+
+        public GZipStream(Stream stream, CompressionMode mode, CompressionLevel level)
+            : this(stream, mode, level, false)
+        {
+        }
+
+        public GZipStream(Stream stream, CompressionMode mode, bool leaveOpen)
+            : this(stream, mode, CompressionLevel.Default, leaveOpen)
+        {
+        }
+
+        public GZipStream(Stream stream, CompressionMode mode, CompressionLevel level, bool leaveOpen)
+        {
+            if (mode == CompressionMode.Decompress)
+            {
+                BaseStream = new System.IO.Compression.DeflateStream(stream, System.IO.Compression.CompressionMode.Decompress, leaveOpen);
+            }
+            else
+            {
+                System.IO.Compression.CompressionLevel l;
+                switch (level)
+                {
+                    case CompressionLevel.BestSpeed:
+                    {
+                        l = System.IO.Compression.CompressionLevel.Fastest;
+                        break;
+                    }
+                    case CompressionLevel.None:
+                    {
+                        l = System.IO.Compression.CompressionLevel.NoCompression;
+                        break;
+                    }
+                    default:
+                    {
+                        l = System.IO.Compression.CompressionLevel.Optimal;
+                        break;
+                    }
+                }
+
+                BaseStream = new System.IO.Compression.DeflateStream(stream, l, leaveOpen);
+
+
+            }
+        }
+
+        #region Stream methods
+
+        /// <summary>
+        /// Indicates whether the stream can be read.
+        /// </summary>
+        /// <remarks>
+        /// The return value depends on whether the captive stream supports reading.
+        /// </remarks>
+        public override bool CanRead
+        {
+            get
+            {
+                if (disposed)
+                {
+                    throw new ObjectDisposedException("GZipStream");
+                }
+                return BaseStream.CanRead;
+            }
+        }
+
+        /// <summary>
+        /// Indicates whether the stream supports Seek operations.
+        /// </summary>
+        /// <remarks>
+        /// Always returns false.
+        /// </remarks>
+        public override bool CanSeek => false;
+
+        /// <summary>
+        /// Indicates whether the stream can be written.
+        /// </summary>
+        /// <remarks>
+        /// The return value depends on whether the captive stream supports writing.
+        /// </remarks>
+        public override bool CanWrite
+        {
+            get
+            {
+                if (disposed)
+                {
+                    throw new ObjectDisposedException("GZipStream");
+                }
+                return BaseStream.CanWrite;
+            }
+        }
+
+        /// <summary>
+        /// Reading this property always throws a <see cref="NotImplementedException"/>.
+        /// </summary>
+        public override long Length => throw new NotSupportedException();
+
+        /// <summary>
+        ///   The position of the stream pointer.
+        /// </summary>
+        ///
+        /// <remarks>
+        ///   Setting this property always throws a <see
+        ///   cref="NotImplementedException"/>. Reading will return the total bytes
+        ///   written out, if used in writing, or the total bytes read in, if used in
+        ///   reading.  The count may refer to compressed bytes or uncompressed bytes,
+        ///   depending on how you've used the stream.
+        /// </remarks>
+        public override long Position
+        {
+            get
+            {
+                switch (mode)
+                {
+                    case Mode.Writer:
+                        return BaseStream.Position + _gzipHeaderByteCount;
+                    case Mode.Reader:
+                        return BaseStream.Position + _gzipHeaderByteCount;
+                    default:
+                        return 0;
+                }
+            }
+
+            set => throw new NotSupportedException();
+        }
+
+        /// <summary>
+        /// Dispose the stream.
+        /// </summary>
+        /// <remarks>
+        /// This may or may not result in a <c>Close()</c> call on the captive stream.
+        /// See the doc on constructors that take a <c>leaveOpen</c> parameter for more information.
+        /// </remarks>
+        protected override void Dispose(bool disposing)
+        {
+            try
+            {
+                if (!disposed)
+                {
+                    if (disposing && (BaseStream != null))
+                    {
+                        BaseStream.Dispose();;
+                    }
+                    disposed = true;
+                }
+            }
+            finally
+            {
+                base.Dispose(disposing);
+            }
+        }
+
+        /// <summary>
+        /// Flush the stream.
+        /// </summary>
+        public override void Flush()
+        {
+            if (disposed)
+            {
+                throw new ObjectDisposedException("GZipStream");
+            }
+            BaseStream.Flush();
+        }
+
+        /// <summary>
+        ///   Read and decompress data from the source stream.
+        /// </summary>
+        ///
+        /// <remarks>
+        ///   With a <c>GZipStream</c>, decompression is done through reading.
+        /// </remarks>
+        ///
+        /// <example>
+        /// <code>
+        /// byte[] working = new byte[WORKING_BUFFER_SIZE];
+        /// using (System.IO.Stream input = System.IO.File.OpenRead(_CompressedFile))
+        /// {
+        ///     using (Stream decompressor= new Ionic.Zlib.GZipStream(input, CompressionMode.Decompress, true))
+        ///     {
+        ///         using (var output = System.IO.File.Create(_DecompressedFile))
+        ///         {
+        ///             int n;
+        ///             while ((n= decompressor.Read(working, 0, working.Length)) !=0)
+        ///             {
+        ///                 output.Write(working, 0, n);
+        ///             }
+        ///         }
+        ///     }
+        /// }
+        /// </code>
+        /// </example>
+        /// <param name="buffer">The buffer into which the decompressed data should be placed.</param>
+        /// <param name="offset">the offset within that data array to put the first byte read.</param>
+        /// <param name="count">the number of bytes to read.</param>
+        /// <returns>the number of bytes actually read</returns>
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            if (disposed)
+            {
+                throw new ObjectDisposedException("GZipStream");
+            }
+            int n = BaseStream.Read(buffer, offset, count);
+
+            // Console.WriteLine("GZipStream::Read(buffer, off({0}), c({1}) = {2}", offset, count, n);
+            // Console.WriteLine( Util.FormatByteArray(buffer, offset, n) );
+
+            if (mode == Mode.Unknown)
+            {
+                _gzipHeaderByteCount = _ReadAndValidateGzipHeader();
+                mode = Mode.Reader;
+                FileName = _GzipFileName;
+                Comment = _GzipComment;
+            }
+            return n;
+        }
+
+
+        private int _ReadAndValidateGzipHeader()
+        {
+            int totalBytesRead = 0;
+
+            // read the header on the first read
+            byte[] header = new byte[10];
+            int n = BaseStream.Read(header, 0, header.Length);
+
+            // workitem 8501: handle edge case (decompress empty stream)
+            if (n == 0)
+            {
+                return 0;
+            }
+
+            if (n != 10)
+            {
+                throw new ZlibException("Not a valid GZIP stream.");
+            }
+
+            if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8)
+            {
+                throw new ZlibException("Bad GZIP header.");
+            }
+
+            Int32 timet = DataConverter.LittleEndian.GetInt32(header, 4);
+            _GzipMtime = UnixEpoch.AddSeconds(timet);
+            totalBytesRead += n;
+            if ((header[3] & 0x04) == 0x04)
+            {
+                // read and discard extra field
+                n = BaseStream.Read(header, 0, 2); // 2-byte length field
+                totalBytesRead += n;
+
+                Int16 extraLength = (Int16)(header[0] + header[1] * 256);
+                byte[] extra = new byte[extraLength];
+                n = BaseStream.Read(extra, 0, extra.Length);
+                if (n != extraLength)
+                {
+                    throw new ZlibException("Unexpected end-of-file reading GZIP header.");
+                }
+                totalBytesRead += n;
+            }
+            if ((header[3] & 0x08) == 0x08)
+            {
+                _GzipFileName = ReadZeroTerminatedString();
+            }
+            if ((header[3] & 0x10) == 0x010)
+            {
+                _GzipComment = ReadZeroTerminatedString();
+            }
+            if ((header[3] & 0x02) == 0x02)
+            {
+                Read(_buf1, 0, 1); // CRC16, ignore
+            }
+
+            return totalBytesRead;
+        }
+
+        private string ReadZeroTerminatedString()
+        {
+            var list = new List<byte>();
+            bool done = false;
+            do
+            {
+                // workitem 7740
+                int n = BaseStream.Read(_buf1, 0, 1);
+                if (n != 1)
+                {
+                    throw new ZlibException("Unexpected EOF reading GZIP header.");
+                }
+                if (_buf1[0] == 0)
+                {
+                    done = true;
+                }
+                else
+                {
+                    list.Add(_buf1[0]);
+                }
+            }
+            while (!done);
+            byte[] a = list.ToArray();
+            return ArchiveEncoding.Default.GetString(a, 0, a.Length);
+        }
+
+        /// <summary>
+        ///   Calling this method always throws a <see cref="NotImplementedException"/>.
+        /// </summary>
+        /// <param name="offset">irrelevant; it will always throw!</param>
+        /// <param name="origin">irrelevant; it will always throw!</param>
+        /// <returns>irrelevant!</returns>
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            throw new NotSupportedException();
+        }
+
+        /// <summary>
+        ///   Calling this method always throws a <see cref="NotImplementedException"/>.
+        /// </summary>
+        /// <param name="value">irrelevant; this method will always throw!</param>
+        public override void SetLength(long value)
+        {
+            throw new NotSupportedException();
+        }
+
+        /// <summary>
+        ///   Write data to the stream.
+        /// </summary>
+        ///
+        /// <remarks>
+        /// <para>
+        ///   If you wish to use the <c>GZipStream</c> to compress data while writing,
+        ///   you can create a <c>GZipStream</c> with <c>CompressionMode.Compress</c>, and a
+        ///   writable output stream.  Then call <c>Write()</c> on that <c>GZipStream</c>,
+        ///   providing uncompressed data as input.  The data sent to the output stream
+        ///   will be the compressed form of the data written.
+        /// </para>
+        ///
+        /// <para>
+        ///   A <c>GZipStream</c> can be used for <c>Read()</c> or <c>Write()</c>, but not
+        ///   both. Writing implies compression.  Reading implies decompression.
+        /// </para>
+        ///
+        /// </remarks>
+        /// <param name="buffer">The buffer holding data to write to the stream.</param>
+        /// <param name="offset">the offset within that data array to find the first byte to write.</param>
+        /// <param name="count">the number of bytes to write.</param>
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            if (disposed)
+            {
+                throw new ObjectDisposedException("GZipStream");
+            }
+            if (mode == Mode.Unknown)
+            {
+                // first write in compression, therefore, emit the GZIP header
+                _gzipHeaderByteCount = EmitHeader();
+                mode = Mode.Writer;
+            }
+
+            BaseStream.Write(buffer, offset, count);
+        }
+
+        #endregion
+
+        public string Comment
+        {
+            get => _GzipComment;
+            set
+            {
+                if (disposed)
+                {
+                    throw new ObjectDisposedException("GZipStream");
+                }
+                _GzipComment = value;
+            }
+        }
+
+        public string FileName
+        {
+            get => _GzipFileName;
+            set
+            {
+                if (disposed)
+                {
+                    throw new ObjectDisposedException("GZipStream");
+                }
+                _GzipFileName = value;
+                if (_GzipFileName == null)
+                {
+                    return;
+                }
+                if (_GzipFileName.IndexOf("/") != -1)
+                {
+                    _GzipFileName = _GzipFileName.Replace("/", "\\");
+                }
+                if (_GzipFileName.EndsWith("\\"))
+                {
+                    throw new InvalidOperationException("Illegal filename");
+                }
+
+                var index = _GzipFileName.IndexOf("\\");
+                if (index != -1)
+                {
+                    // trim any leading path
+                    int length = _GzipFileName.Length;
+                    int num = length;
+                    while (--num >= 0)
+                    {
+                        char c = _GzipFileName[num];
+                        if (c == '\\')
+                        {
+                            _GzipFileName = _GzipFileName.Substring(num + 1, length - num - 1);
+                        }
+                    }
+                }
+            }
+        }
+
+        private int EmitHeader()
+        {
+            byte[] commentBytes = (Comment == null) ? null : ArchiveEncoding.Default.GetBytes(Comment);
+            byte[] filenameBytes = (FileName == null) ? null : ArchiveEncoding.Default.GetBytes(FileName);
+
+            int cbLength = (Comment == null) ? 0 : commentBytes.Length + 1;
+            int fnLength = (FileName == null) ? 0 : filenameBytes.Length + 1;
+
+            int bufferLength = 10 + cbLength + fnLength;
+            var header = new byte[bufferLength];
+            int i = 0;
+
+            // ID
+            header[i++] = 0x1F;
+            header[i++] = 0x8B;
+
+            // compression method
+            header[i++] = 8;
+            byte flag = 0;
+            if (Comment != null)
+            {
+                flag ^= 0x10;
+            }
+            if (FileName != null)
+            {
+                flag ^= 0x8;
+            }
+
+            // flag
+            header[i++] = flag;
+
+            // mtime
+            if (!LastModified.HasValue)
+            {
+                LastModified = DateTime.Now;
+            }
+            TimeSpan delta = LastModified.Value - UnixEpoch;
+            var timet = (Int32)delta.TotalSeconds;
+            DataConverter.LittleEndian.PutBytes(header, i, timet);
+            i += 4;
+
+            // xflg
+            header[i++] = 0; // this field is totally useless
+
+            // OS
+            header[i++] = 0xFF; // 0xFF == unspecified
+
+            // extra field length - only if FEXTRA is set, which it is not.
+            //header[i++]= 0;
+            //header[i++]= 0;
+
+            // filename
+            if (fnLength != 0)
+            {
+                Array.Copy(filenameBytes, 0, header, i, fnLength - 1);
+                i += fnLength - 1;
+                header[i++] = 0; // terminate
+            }
+
+            // comment
+            if (cbLength != 0)
+            {
+                Array.Copy(commentBytes, 0, header, i, cbLength - 1);
+                i += cbLength - 1;
+                header[i++] = 0; // terminate
+            }
+
+            BaseStream.Write(header, 0, header.Length);
+
+            return header.Length; // bytes written
+        }
+    }
+}
+#endif

src/SharpCompress/Compressors/Deflate/GZipStream.cs

@@ -1,3 +1,4 @@
+#if NETSTANDARD1_0
 // GZipStream.cs
 // ------------------------------------------------------------------
 //
@@ -476,4 +477,5 @@ namespace SharpCompress.Compressors.Deflate
             return header.Length; // bytes written
         }
     }
-}
+}
+#endif