X-Git-Url: https://oss.titaniummirror.com/gitweb?a=blobdiff_plain;f=zlib%2Fcontrib%2Fdotzlib%2FDotZLib%2FGZipStream.cs;fp=zlib%2Fcontrib%2Fdotzlib%2FDotZLib%2FGZipStream.cs;h=f861675b518ff730019e08af9869ace8d475a768;hb=6fed43773c9b0ce596dca5686f37ac3fc0fa11c0;hp=0000000000000000000000000000000000000000;hpb=27b11d56b743098deb193d510b337ba22dc52e5c;p=msp430-gcc.git diff --git a/zlib/contrib/dotzlib/DotZLib/GZipStream.cs b/zlib/contrib/dotzlib/DotZLib/GZipStream.cs new file mode 100644 index 00000000..f861675b --- /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 +{ + /// + /// Implements a compressed , in GZip (.gz) format. + /// + 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 + /// + /// Creates a new file as a writeable GZipStream + /// + /// The name of the compressed file to create + /// The compression level to use when adding data + /// If an error occurred in the internal zlib function + 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); + } + + /// + /// Opens an existing file as a readable GZipStream + /// + /// The name of the file to open + /// If an error occurred in the internal zlib function + 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 + /// + /// Returns true of this stream can be read from, false otherwise + /// + public override bool CanRead + { + get + { + return !_isWriting; + } + } + + + /// + /// Returns false. + /// + public override bool CanSeek + { + get + { + return false; + } + } + + /// + /// Returns true if this tsream is writeable, false otherwise + /// + public override bool CanWrite + { + get + { + return _isWriting; + } + } + #endregion + + #region Destructor & IDispose stuff + + /// + /// Destroys this instance + /// + ~GZipStream() + { + cleanUp(false); + } + + /// + /// Closes the external file handle + /// + 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 + /// + /// Attempts to read a number of bytes from the stream. + /// + /// The destination data buffer + /// The index of the first destination byte in buffer + /// The number of bytes requested + /// The number of bytes read + /// If buffer is null + /// If count or offset are negative + /// If offset + count is > buffer.Length + /// If this stream is not readable. + /// If this stream has been disposed. + 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; + } + + /// + /// Attempts to read a single byte from the stream. + /// + /// The byte that was read, or -1 in case of error or End-Of-File + public override int ReadByte() + { + if (!CanRead) throw new NotSupportedException(); + if (_isDisposed) throw new ObjectDisposedException("GZipStream"); + return gzgetc(_gzFile); + } + + /// + /// Writes a number of bytes to the stream + /// + /// + /// + /// + /// If buffer is null + /// If count or offset are negative + /// If offset + count is > buffer.Length + /// If this stream is not writeable. + /// If this stream has been disposed. + 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(); + } + } + + /// + /// Writes a single byte to the stream + /// + /// The byte to add to the stream. + /// If this stream is not writeable. + /// If this stream has been disposed. + 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 + /// + /// Not supported. + /// + /// + /// Always thrown + public override void SetLength(long value) + { + throw new NotSupportedException(); + } + + /// + /// Not suppported. + /// + /// + /// + /// + /// Always thrown + public override long Seek(long offset, SeekOrigin origin) + { + throw new NotSupportedException(); + } + + /// + /// Flushes the GZipStream. + /// + /// In this implementation, this method does nothing. This is because excessive + /// flushing may degrade the achievable compression rates. + public override void Flush() + { + // left empty on purpose + } + + /// + /// Gets/sets the current position in the GZipStream. Not suppported. + /// + /// In this implementation this property is not supported + /// Always thrown + public override long Position + { + get + { + throw new NotSupportedException(); + } + set + { + throw new NotSupportedException(); + } + } + + /// + /// Gets the size of the stream. Not suppported. + /// + /// In this implementation this property is not supported + /// Always thrown + public override long Length + { + get + { + throw new NotSupportedException(); + } + } + #endregion + } +}