diff options
Diffstat (limited to 'zlib/contrib/dotzlib/DotZLib/GZipStream.cs')
| -rw-r--r-- | zlib/contrib/dotzlib/DotZLib/GZipStream.cs | 301 |
1 files changed, 301 insertions, 0 deletions
diff --git a/zlib/contrib/dotzlib/DotZLib/GZipStream.cs b/zlib/contrib/dotzlib/DotZLib/GZipStream.cs new file mode 100644 index 00000000000..b161300b185 --- /dev/null +++ b/zlib/contrib/dotzlib/DotZLib/GZipStream.cs @@ -0,0 +1,301 @@ +//
+// © Copyright Henrik Ravn 2004
+//
+// Use, modification and distribution are subject to the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+
+namespace DotZLib
+{
+ /// <summary>
+ /// Implements a compressed <see cref="Stream"/>, in GZip (.gz) format.
+ /// </summary>
+ public class GZipStream : Stream, IDisposable
+ {
+ #region Dll Imports
+ [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl, CharSet=CharSet.Ansi)]
+ private static extern IntPtr gzopen(string name, string mode);
+
+ [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
+ private static extern int gzclose(IntPtr gzFile);
+
+ [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
+ private static extern int gzwrite(IntPtr gzFile, int data, int length);
+
+ [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
+ private static extern int gzread(IntPtr gzFile, int data, int length);
+
+ [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
+ private static extern int gzgetc(IntPtr gzFile);
+
+ [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
+ private static extern int gzputc(IntPtr gzFile, int c);
+
+ #endregion
+
+ #region Private data
+ private IntPtr _gzFile;
+ private bool _isDisposed = false;
+ private bool _isWriting;
+ #endregion
+
+ #region Constructors
+ /// <summary>
+ /// Creates a new file as a writeable GZipStream
+ /// </summary>
+ /// <param name="fileName">The name of the compressed file to create</param>
+ /// <param name="level">The compression level to use when adding data</param>
+ /// <exception cref="ZLibException">If an error occurred in the internal zlib function</exception>
+ public GZipStream(string fileName, CompressLevel level)
+ {
+ _isWriting = true;
+ _gzFile = gzopen(fileName, String.Format("wb{0}", (int)level));
+ if (_gzFile == IntPtr.Zero)
+ throw new ZLibException(-1, "Could not open " + fileName);
+ }
+
+ /// <summary>
+ /// Opens an existing file as a readable GZipStream
+ /// </summary>
+ /// <param name="fileName">The name of the file to open</param>
+ /// <exception cref="ZLibException">If an error occurred in the internal zlib function</exception>
+ public GZipStream(string fileName)
+ {
+ _isWriting = false;
+ _gzFile = gzopen(fileName, "rb");
+ if (_gzFile == IntPtr.Zero)
+ throw new ZLibException(-1, "Could not open " + fileName);
+
+ }
+ #endregion
+
+ #region Access properties
+ /// <summary>
+ /// Returns true of this stream can be read from, false otherwise
+ /// </summary>
+ public override bool CanRead
+ {
+ get
+ {
+ return !_isWriting;
+ }
+ }
+
+
+ /// <summary>
+ /// Returns false.
+ /// </summary>
+ public override bool CanSeek
+ {
+ get
+ {
+ return false;
+ }
+ }
+
+ /// <summary>
+ /// Returns true if this tsream is writeable, false otherwise
+ /// </summary>
+ public override bool CanWrite
+ {
+ get
+ {
+ return _isWriting;
+ }
+ }
+ #endregion
+
+ #region Destructor & IDispose stuff
+
+ /// <summary>
+ /// Destroys this instance
+ /// </summary>
+ ~GZipStream()
+ {
+ cleanUp(false);
+ }
+
+ /// <summary>
+ /// Closes the external file handle
+ /// </summary>
+ public void Dispose()
+ {
+ cleanUp(true);
+ }
+
+ // Does the actual closing of the file handle.
+ private void cleanUp(bool isDisposing)
+ {
+ if (!_isDisposed)
+ {
+ gzclose(_gzFile);
+ _isDisposed = true;
+ }
+ }
+ #endregion
+
+ #region Basic reading and writing
+ /// <summary>
+ /// Attempts to read a number of bytes from the stream.
+ /// </summary>
+ /// <param name="buffer">The destination data buffer</param>
+ /// <param name="offset">The index of the first destination byte in <c>buffer</c></param>
+ /// <param name="count">The number of bytes requested</param>
+ /// <returns>The number of bytes read</returns>
+ /// <exception cref="ArgumentNullException">If <c>buffer</c> is null</exception>
+ /// <exception cref="ArgumentOutOfRangeException">If <c>count</c> or <c>offset</c> are negative</exception>
+ /// <exception cref="ArgumentException">If <c>offset</c> + <c>count</c> is > buffer.Length</exception>
+ /// <exception cref="NotSupportedException">If this stream is not readable.</exception>
+ /// <exception cref="ObjectDisposedException">If this stream has been disposed.</exception>
+ public override int Read(byte[] buffer, int offset, int count)
+ {
+ if (!CanRead) throw new NotSupportedException();
+ if (buffer == null) throw new ArgumentNullException();
+ if (offset < 0 || count < 0) throw new ArgumentOutOfRangeException();
+ if ((offset+count) > buffer.Length) throw new ArgumentException();
+ if (_isDisposed) throw new ObjectDisposedException("GZipStream");
+
+ GCHandle h = GCHandle.Alloc(buffer, GCHandleType.Pinned);
+ int result;
+ try
+ {
+ result = gzread(_gzFile, h.AddrOfPinnedObject().ToInt32() + offset, count);
+ if (result < 0)
+ throw new IOException();
+ }
+ finally
+ {
+ h.Free();
+ }
+ return result;
+ }
+
+ /// <summary>
+ /// Attempts to read a single byte from the stream.
+ /// </summary>
+ /// <returns>The byte that was read, or -1 in case of error or End-Of-File</returns>
+ public override int ReadByte()
+ {
+ if (!CanRead) throw new NotSupportedException();
+ if (_isDisposed) throw new ObjectDisposedException("GZipStream");
+ return gzgetc(_gzFile);
+ }
+
+ /// <summary>
+ /// Writes a number of bytes to the stream
+ /// </summary>
+ /// <param name="buffer"></param>
+ /// <param name="offset"></param>
+ /// <param name="count"></param>
+ /// <exception cref="ArgumentNullException">If <c>buffer</c> is null</exception>
+ /// <exception cref="ArgumentOutOfRangeException">If <c>count</c> or <c>offset</c> are negative</exception>
+ /// <exception cref="ArgumentException">If <c>offset</c> + <c>count</c> is > buffer.Length</exception>
+ /// <exception cref="NotSupportedException">If this stream is not writeable.</exception>
+ /// <exception cref="ObjectDisposedException">If this stream has been disposed.</exception>
+ public override void Write(byte[] buffer, int offset, int count)
+ {
+ if (!CanWrite) throw new NotSupportedException();
+ if (buffer == null) throw new ArgumentNullException();
+ if (offset < 0 || count < 0) throw new ArgumentOutOfRangeException();
+ if ((offset+count) > buffer.Length) throw new ArgumentException();
+ if (_isDisposed) throw new ObjectDisposedException("GZipStream");
+
+ GCHandle h = GCHandle.Alloc(buffer, GCHandleType.Pinned);
+ try
+ {
+ int result = gzwrite(_gzFile, h.AddrOfPinnedObject().ToInt32() + offset, count);
+ if (result < 0)
+ throw new IOException();
+ }
+ finally
+ {
+ h.Free();
+ }
+ }
+
+ /// <summary>
+ /// Writes a single byte to the stream
+ /// </summary>
+ /// <param name="value">The byte to add to the stream.</param>
+ /// <exception cref="NotSupportedException">If this stream is not writeable.</exception>
+ /// <exception cref="ObjectDisposedException">If this stream has been disposed.</exception>
+ public override void WriteByte(byte value)
+ {
+ if (!CanWrite) throw new NotSupportedException();
+ if (_isDisposed) throw new ObjectDisposedException("GZipStream");
+
+ int result = gzputc(_gzFile, (int)value);
+ if (result < 0)
+ throw new IOException();
+ }
+ #endregion
+
+ #region Position & length stuff
+ /// <summary>
+ /// Not supported.
+ /// </summary>
+ /// <param name="value"></param>
+ /// <exception cref="NotSupportedException">Always thrown</exception>
+ public override void SetLength(long value)
+ {
+ throw new NotSupportedException();
+ }
+
+ /// <summary>
+ /// Not suppported.
+ /// </summary>
+ /// <param name="offset"></param>
+ /// <param name="origin"></param>
+ /// <returns></returns>
+ /// <exception cref="NotSupportedException">Always thrown</exception>
+ public override long Seek(long offset, SeekOrigin origin)
+ {
+ throw new NotSupportedException();
+ }
+
+ /// <summary>
+ /// Flushes the <c>GZipStream</c>.
+ /// </summary>
+ /// <remarks>In this implementation, this method does nothing. This is because excessive
+ /// flushing may degrade the achievable compression rates.</remarks>
+ public override void Flush()
+ {
+ // left empty on purpose
+ }
+
+ /// <summary>
+ /// Gets/sets the current position in the <c>GZipStream</c>. Not suppported.
+ /// </summary>
+ /// <remarks>In this implementation this property is not supported</remarks>
+ /// <exception cref="NotSupportedException">Always thrown</exception>
+ public override long Position
+ {
+ get
+ {
+ throw new NotSupportedException();
+ }
+ set
+ {
+ throw new NotSupportedException();
+ }
+ }
+
+ /// <summary>
+ /// Gets the size of the stream. Not suppported.
+ /// </summary>
+ /// <remarks>In this implementation this property is not supported</remarks>
+ /// <exception cref="NotSupportedException">Always thrown</exception>
+ public override long Length
+ {
+ get
+ {
+ throw new NotSupportedException();
+ }
+ }
+ #endregion
+ }
+}
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