DotZLib.cs

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//
// © 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;
using System.Text;


namespace DotZLib
{

    #region Internal types

    internal enum FlushTypes
    {
        None,  Partial,  Sync,  Full,  Finish,  Block
    }

    #region ZStream structure
    // internal mapping of the zlib zstream structure for marshalling
    [StructLayoutAttribute(LayoutKind.Sequential, Pack=4, Size=0, CharSet=CharSet.Ansi)]
    internal struct ZStream
    {
        public IntPtr next_in;
        public uint avail_in;
        public uint total_in;

        public IntPtr next_out;
        public uint avail_out;
        public uint total_out;

        [MarshalAs(UnmanagedType.LPStr)]
        string msg;
        uint state;

        uint zalloc;
        uint zfree;
        uint opaque;

        int data_type;
        public uint adler;
        uint reserved;
    }

    #endregion

    #endregion

    #region Public enums
    public enum CompressLevel : int
    {
        Default = -1,
        None = 0,
        Best = 9,
        Fastest = 1
    }
    #endregion

    #region Exception classes
    public class ZLibException : ApplicationException
    {
        public ZLibException(int errorCode, string msg) : base(String.Format("ZLib error {0} {1}", errorCode, msg))
        {
        }

        public ZLibException(int errorCode) : base(String.Format("ZLib error {0}", errorCode))
        {
        }
    }
    #endregion

    #region Interfaces

    public interface ChecksumGenerator
    {
        uint Value { get; }

        void Reset();

        void Update(byte[] data);

        void Update(byte[] data, int offset, int count);

        void Update(string data);

        void Update(string data, Encoding encoding);
    }


    public delegate void DataAvailableHandler(byte[] data, int startIndex, int count);

    public interface Codec
    {
        event DataAvailableHandler DataAvailable;

        void Add(byte[] data);

        void Add(byte[] data, int offset, int count);

        void Finish();

        uint Checksum { get; }


    }

    #endregion

    #region Classes
    public class Info
    {
        #region DLL imports
        [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
        private static extern uint zlibCompileFlags();

        [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
        private static extern string zlibVersion();
        #endregion

        #region Private stuff
        private uint _flags;

        // helper function that unpacks a bitsize mask
        private static int bitSize(uint bits)
        {
            switch (bits)
            {
                case 0: return 16;
                case 1: return 32;
                case 2: return 64;
            }
            return -1;
        }
        #endregion

        public Info()
        {
            _flags = zlibCompileFlags();
        }

        public bool HasDebugInfo { get { return 0 != (_flags & 0x100); } }

        public bool UsesAssemblyCode { get { return 0 != (_flags & 0x200); } }

        public int SizeOfUInt { get { return bitSize(_flags & 3); } }

        public int SizeOfULong { get { return bitSize((_flags >> 2) & 3); } }

        public int SizeOfPointer { get { return bitSize((_flags >> 4) & 3); } }

        public int SizeOfOffset { get { return bitSize((_flags >> 6) & 3); } }

        public static string Version { get { return zlibVersion(); } }
    }

    #endregion

}