SpeechEvent.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Speech / Src / Internal / SapiInterop / SpeechEvent.cs / 1 / SpeechEvent.cs
                        
                        
                            //------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------- 

using System; 
using System.Runtime.InteropServices; 
using System.Speech.AudioFormat;
 
namespace System.Speech.Internal.SapiInterop
{

    // Internal helper class that wraps a SAPI event structure. 
    // A new instance is created by calling SpeechEvent.TryCreateSpeechEvent
    // Disposing this class will dispose all unmanmanaged memory. 
    internal class SpeechEvent : IDisposable 
    {
        //******************************************************************* 
        //
        // Constructors
        //
        //******************************************************************* 

        #region Constructors 
 
        private SpeechEvent(SPEVENTENUM eEventId, SPEVENTLPARAMTYPE elParamType,
            ulong ullAudioStreamOffset, IntPtr wParam, IntPtr lParam) 
        {
            // We make a copy of the SPEVENTEX data but that's okay because the lParam will only be deleted once.
            _eventId = eEventId;
            _paramType = elParamType; 
            _audioStreamOffset = ullAudioStreamOffset;
            _wParam = (ulong)wParam.ToInt64(); 
            _lParam = (ulong)lParam; 

            // Let the GC know if we have a unmanaged object with a given size 
            if (_paramType == SPEVENTLPARAMTYPE.SPET_LPARAM_IS_POINTER || _paramType == SPEVENTLPARAMTYPE.SPET_LPARAM_IS_STRING)
            {
                GC.AddMemoryPressure(_sizeMemoryPressure = Marshal.SizeOf(_lParam));
            } 
        }
 
        private SpeechEvent(SPEVENT sapiEvent, SpeechAudioFormatInfo audioFormat) 
 			: this(sapiEvent.eEventId, sapiEvent.elParamType, sapiEvent.ullAudioStreamOffset, sapiEvent.wParam, sapiEvent.lParam)
        { 
            if (audioFormat == null || audioFormat.EncodingFormat == 0)
            {
                _audioPosition = TimeSpan.Zero;
            } 
            else
            { 
                _audioPosition = audioFormat.AverageBytesPerSecond > 0 ? new TimeSpan ((long) ((sapiEvent.ullAudioStreamOffset * TimeSpan.TicksPerSecond) / (ulong) audioFormat.AverageBytesPerSecond)) : TimeSpan.Zero; 
            }
        } 

        private SpeechEvent(SPEVENTEX sapiEventEx) : this(sapiEventEx.eEventId, sapiEventEx.elParamType, sapiEventEx.ullAudioStreamOffset, sapiEventEx.wParam, sapiEventEx.lParam)
        {
            _audioPosition = new TimeSpan((long)sapiEventEx.ullAudioTimeOffset); 
        }
 
        ~SpeechEvent() 
        {
            Dispose (); 
        }

        public void Dispose ()
        { 
            // General code to free event data
            if (_lParam != 0) 
            { 
                if (_paramType == SPEVENTLPARAMTYPE.SPET_LPARAM_IS_TOKEN || _paramType == SPEVENTLPARAMTYPE.SPET_LPARAM_IS_OBJECT)
                { 
                    Marshal.Release ((IntPtr) _lParam);
                }
                else
                { 
                    if (_paramType == SPEVENTLPARAMTYPE.SPET_LPARAM_IS_POINTER || _paramType == SPEVENTLPARAMTYPE.SPET_LPARAM_IS_STRING)
                    { 
                        Marshal.FreeCoTaskMem ((IntPtr) _lParam); 
                    }
                } 

                // Update the GC
                if (_sizeMemoryPressure > 0)
                { 
                    GC.RemoveMemoryPressure (_sizeMemoryPressure);
                    _sizeMemoryPressure = 0; 
                } 

                // Mark the object as beeing freed 
                _lParam = 0;
            }
            GC.SuppressFinalize (this);
        } 

        #endregion 
 
        //********************************************************************
        // 
        // Internal Methods
        //
        //*******************************************************************
 
        #region Internal Methods
 
        // This tries to get an event from the ISpEventSource. 
        // If there are no events queued then null is returned.
        // Otherwise a new SpeechEvent is created and returned. 
        static internal SpeechEvent TryCreateSpeechEvent(ISpEventSource sapiEventSource, bool additionalSapiFeatures, SpeechAudioFormatInfo audioFormat)
        {
            uint fetched;
            SpeechEvent speechEvent = null; 
            if (additionalSapiFeatures)
            { 
                SPEVENTEX sapiEventEx; 
                ((ISpEventSource2)sapiEventSource).GetEventsEx(1, out sapiEventEx, out fetched);
                if (fetched == 1) 
                {
                    speechEvent = new SpeechEvent(sapiEventEx);
                }
            } 
            else
            { 
                SPEVENT sapiEvent; 
                sapiEventSource.GetEvents(1, out sapiEvent, out fetched);
                if (fetched == 1) 
                {
                    speechEvent = new SpeechEvent(sapiEvent, audioFormat);
                }
            } 

            return speechEvent; 
        } 

        #endregion 

        //********************************************************************
        //
        // Internal Properties 
        //
        //******************************************************************** 
 
        #region Internal Properties
 
        internal SPEVENTENUM EventId
        {
            get { return _eventId; }
        } 
        internal ulong AudioStreamOffset
        { 
            get { return _audioStreamOffset; } 
        }
 
        // The WParam is returned as a 64-bit value since unmanaged wParam is always 32 or 64 depending on architecture.
        // This is always some kind of numeric value in SAPI - it is never a pointer that needs to freed.
        internal ulong WParam
        { 
            get { return _wParam; }
        } 
 
        internal ulong LParam
        { 
            get { return _lParam; }
        }

        internal TimeSpan AudioPosition 
        {
            get { return _audioPosition; } 
        } 

        #endregion 

        //*******************************************************************
        //
        // Private Fields 
        //
        //******************************************************************** 
 
        #region Private Fields
 
        private SPEVENTENUM _eventId;
        private SPEVENTLPARAMTYPE _paramType;
        private ulong _audioStreamOffset;
        private ulong _wParam; 
        private ulong _lParam;
        private TimeSpan _audioPosition; 
        private int _sizeMemoryPressure; 

        #endregion 
    }


    internal enum SPEVENTLPARAMTYPE : ushort 
    {
        SPET_LPARAM_IS_UNDEFINED = 0x0000, 
        SPET_LPARAM_IS_TOKEN = 0x0001, 
        SPET_LPARAM_IS_OBJECT = 0x0002,
        SPET_LPARAM_IS_POINTER = 0x0003, 
        SPET_LPARAM_IS_STRING = 0x0004
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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SpeechEvent.cs source code in C# .NET

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