Translate Delphi export to C#/Vb.Net

Question

I'm writting a simple wrapper of the Subtitle Workshop library, but I get stuck translating this Delphi export to C# or Vb.Net:

procedure GetSubtitleText(Time: Integer; Text: {$IFDEF UTF8}PWideChar{$ELSE}PChar{$ENDIF}; var BufferLen: Integer); stdcall;
var
  FText : {$IFDEF UTF8}WideString{$ELSE}String{$ENDIF};
begin
  FText := DisplaySubtitle(Subtitles, Time);

  if BufferLen > 0 then
{$IFDEF UTF8}
//    Text := Copy(FText, 1, BufferLen)
    Text := StringToWideChar(FText, Text, BufferLen)
{$ELSE}
    StrLCopy(Text, PChar(FText), BufferLen)
{$ENDIF}
  else
    BufferLen := Length(FText);
end;

I'm not understanding how to translate the conditionals of the Text parameter.

This is what I did:

<SuppressUnmanagedCodeSecurity>
<DllImport("SubtitleAPI.dll", EntryPoint:="GetSubtitleText", CharSet:=CharSet.Ansi)>
Friend Shared Sub GetSubtitleText(
       <MarshalAs(UnmanagedType.I4)> ByVal time As Integer,
       <MarshalAs(UnmanagedType.LPStr)> ByVal text As StringBuilder,
       <MarshalAs(UnmanagedType.I4)> ByRef bufferLength As Integer
)
End Sub

It seems to work as expected, however, I would like to ensure that I wrote it correctly.

Answer 1

Your translation is fine, so long as UTF8 is not defined when the Delphi code was compiled. If UTF8 is defined then you would need to marshal as LPWStr . And I have to assume that the Delphi code is compiled with an ANSI version of Delphi, so that PChar maps to PAnsiChar . The Delphi code will be totally broken if you try to compile it with Delphi 2009 or later.

There's not much point in specifying CharSet.Ansi if you explicitly mark every parameter with an explicit MarshalAs attribute.

The Delphi code is quite odd. The author seems not to know the difference between UTF-8 and UTF-16. In Delphi PWideChar and WideString are UTF-16 encoded. The call to StrLCopy passes the wrong buffer length, it should pass BufferLen - 1 due to a very poor design of that RTL function. The code should also set BufferLen to the number of characters copied, but does not.

You can work around that in your .net code. I'll write C# because that's what I know. I'm sure that you will understand it:

int len = 0;
GetSubtitleText(time, null, len);
StringBuilder sb = new StringBuilder(len);
len++; // work around poor design/use of StrLCopy 
GetSubtitleText(time, sb, len);

On the face of it, I would be somewhat sceptical of this Delphi code. You should be on your guard. At least you have the source code for it!

Answer 2

I just would like to share the P/Invokes that I wrote in Vb.Net:

' ***********************************************************************
' Author   : Elektro
' Modified : 18-March-2016
' ***********************************************************************

#Region " Public Members Summary "

#Region " Functions "

' OpenFile(String, Single, Integer, Boolean, Boolean) As Boolean
' SaveFile(String, Integer, Single, Integer, Integer) As Boolean

' GetPlaybackDelay() As Integer
' SetAbsoluteDelay(Integer, Integer, Integer) As Boolean

' GetFormatIndex(String) As Integer
' GetFormatInformation(Integer, StringBuilder, StringBuilder, Integer, Integer) As Boolean

' GetSubtitleLineCount() As Integer
' GetSubtitleLine(Integer, Integer, Integer, StringBuilder, Integer) As Boolean

' AddSubtitleLine(Integer, Integer, String) As Integer
' InsertSubtitleLine(Integer, Integer, Integer, String) As Boolean
' DeleteSubtitleLine(Integer) As Boolean
' CreateNewSubtitleLine()

#End Region

#Region " Methods "

' ClearSubtitleLines()
' CloseFile()
' GetCurrentFormatName(StringBuilder, Integer, Integer)
' GetFormatName(Integer, StringBuilder, Integer)
' GetSubtitleText(Integer, StringBuilder, Integer)
' SetPlaybackDelay(Integer)

#End Region

#End Region

#Region " Option Statements "

Option Strict On
Option Explicit On
Option Infer Off

#End Region

#Region " Imports "

Imports System
Imports System.Linq
Imports System.Runtime.InteropServices
Imports System.Security

#End Region

#Region " P/Invoke "

Namespace SubtitleWorkshop.Interop

    ''' ----------------------------------------------------------------------------------------------------
    ''' <summary>
    ''' Platform Invocation methods (P/Invoke), access unmanaged code.
    ''' <para></para>
    ''' This class suppresses stack walks for unmanaged code permission. 
    ''' <see cref="System.Security.SuppressUnmanagedCodeSecurityAttribute"/> is applied to this class.
    ''' <para></para>
    ''' This class is for methods that are safe for anyone to call.
    ''' <para></para>
    ''' Callers of these methods are not required to perform a full security review to make sure that the 
    ''' usage is secure because the methods are harmless for any caller.
    ''' </summary>
    ''' ----------------------------------------------------------------------------------------------------
    ''' <remarks>
    ''' <see href="http://msdn.microsoft.com/en-us/library/ms182161.aspx"/>
    ''' </remarks>
    ''' ----------------------------------------------------------------------------------------------------
    <SuppressUnmanagedCodeSecurity>
    Friend NotInheritable Class SafeNativeMethods

#Region " Methods "

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Opens the specified subtitle file.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="filepath">
        ''' The source subtitle filepath.
        ''' </param>
        ''' 
        ''' <param name="fps">
        ''' The subtitle FPS.
        ''' </param>
        ''' 
        ''' <param name="formatIndex">
        ''' The subtitle format index.
        ''' </param>
        ''' 
        ''' <param name="append">
        ''' If <see langword="True"/>, appends to the end of the subtitle file.
        ''' </param>
        ''' 
        ''' <param name="reCalcTimeValues">
        ''' If <see langword="True"/>, recalculates the time values of the subtitle.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' <see langword="True"/> if the specified subtitle file was open successfully, otherwise, <see langword="False"/>.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="LoadSubtitleFile", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Function OpenFile(<MarshalAs(UnmanagedType.LPStr)> ByVal filepath As String,
                                        <MarshalAs(UnmanagedType.R4)> ByVal fps As Single,
                                        <MarshalAs(UnmanagedType.I4)> ByVal formatIndex As Integer,
                                        <MarshalAs(UnmanagedType.Bool)> ByVal append As Boolean,
                                        <MarshalAs(UnmanagedType.Bool)> ByVal reCalcTimeValues As Boolean
        ) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Closes the current subtitle file.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="CloseSubtitleFile", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Sub CloseFile()
        End Sub

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Saves (or converts) the current subtitle file.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="filepath">
        ''' The target subtitle filepath.
        ''' </param>
        ''' 
        ''' <param name="formatIndex">
        ''' The target subtitle format.
        ''' </param>
        ''' 
        ''' <param name="fps">
        ''' The target subtitle FPS.
        ''' </param>
        ''' 
        ''' <param name="fromIndex">
        ''' The starting index to copy from the source subtitle lines.
        ''' </param>
        ''' 
        ''' <param name="toIndex">
        ''' The ending index to copy from the source subtitle lines.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' <see langword="True"/> if the operation success, otherwise, <see langword="False"/>.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="SaveSubtitleFile", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Function SaveFile(<MarshalAs(UnmanagedType.LPStr)> ByVal filepath As String,
                                        <MarshalAs(UnmanagedType.I4)> ByVal formatIndex As Integer,
                                        <MarshalAs(UnmanagedType.R4)> ByVal fps As Single,
                                        <MarshalAs(UnmanagedType.I4)> ByVal fromIndex As Integer,
                                        <MarshalAs(UnmanagedType.I4)> ByVal toIndex As Integer
        ) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets the format index of the specified subtitle format name.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="formatName">
        ''' The name of the subtitle format.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' The subtitle format index.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="GetFormatIndex", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Function GetFormatIndex(<MarshalAs(UnmanagedType.LPStr)> ByVal formatName As String
        ) As <MarshalAs(UnmanagedType.I4)> Integer
        End Function

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets the format name of the specified subtitle format index.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="formatIndex">
        ''' The index of the subtitle format.
        ''' </param>
        ''' 
        ''' <param name="buffer">
        ''' The string buffer to store the the subtitle format name.
        ''' </param>
        ''' 
        ''' <param name="refBufferLength">
        ''' A by-reference variable that indicates the length of <paramref name="buffer"/>.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="GetFormatName", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Sub GetFormatName(<MarshalAs(UnmanagedType.I4)> ByVal formatIndex As Integer,
                                        <MarshalAs(UnmanagedType.LPStr)> ByVal buffer As StringBuilder,
                                        <MarshalAs(UnmanagedType.I4)> ByRef refBufferLength As Integer
        )
        End Sub

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets information of the specified subtitle format index.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="formatIndex">
        ''' The index of the subtitle format.
        ''' </param>
        ''' 
        ''' <param name="bufferDescription">
        ''' The string buffer to store the the subtitle format description.
        ''' </param>
        ''' 
        ''' <param name="bufferExtensions">
        ''' The string buffer to store the the subtitle format extensions.
        ''' </param>
        ''' 
        ''' <param name="refBufferDescriptionLength">
        ''' A by-reference variable that indicates the length of <paramref name="bufferDescription"/>.
        ''' </param>
        ''' 
        ''' <param name="refBufferExtensionsLength">
        ''' A by-reference variable that indicates the length of <paramref name="bufferExtensions"/>.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' <see langword="True"/> if the operation success, otherwise, <see langword="False"/>.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="GetFormatInformation", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Function GetFormatInformation(<MarshalAs(UnmanagedType.I4)> ByVal formatIndex As Integer,
                                                    <MarshalAs(UnmanagedType.LPStr)> ByVal bufferDescription As StringBuilder,
                                                    <MarshalAs(UnmanagedType.LPStr)> ByVal bufferExtensions As StringBuilder,
                                                    <MarshalAs(UnmanagedType.I4)> ByRef refBufferDescriptionLength As Integer,
                                                    <MarshalAs(UnmanagedType.I4)> ByRef refBufferExtensionsLength As Integer
        ) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets the subtitle format name of the current subtitle file.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="buffer">
        ''' The string buffer to store the the subtitle format name.
        ''' </param>
        ''' 
        ''' <param name="refIndex">
        ''' A by-reference variable that stores the subtitle format name.
        ''' </param>
        ''' 
        ''' <param name="refBufferLength">
        ''' A by-reference variable that indicates the length of <paramref name="buffer"/>.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="GetCurrentFormat", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Sub GetCurrentFormatName(<MarshalAs(UnmanagedType.LPStr)> ByVal buffer As StringBuilder,
                                               <MarshalAs(UnmanagedType.I4)> ByRef refIndex As Integer,
                                               <MarshalAs(UnmanagedType.I4)> ByRef refBufferLength As Integer
        )
        End Sub

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets the line count of the current subtitle file.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' The line count.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="GetSubtitleCount", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Function GetSubtitleLineCount(
        ) As <MarshalAs(UnmanagedType.I4)> Integer
        End Function

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets the subtitle text at the specified time on the current subtitle file. 
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="time">
        ''' The time, in milliseconds.
        ''' </param>
        ''' 
        ''' <param name="buffer">
        ''' The string buffer to store the the subtitle text.
        ''' </param>
        ''' 
        ''' <param name="refBufferLength">
        ''' A by-reference variable that indicates the length of <paramref name="buffer"/>.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="GetSubtitleText", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Sub GetSubtitleText(<MarshalAs(UnmanagedType.I4)> ByVal time As Integer,
                                          <MarshalAs(UnmanagedType.LPStr)> ByVal buffer As StringBuilder,
                                          <MarshalAs(UnmanagedType.I4)> ByRef refBufferLength As Integer
        )
        End Sub

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets the subtitle text at the specified line of the current subtitle file. 
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="lineIndex">
        ''' The line index.
        ''' </param>
        ''' 
        ''' <param name="refStartTime">
        ''' A by-reference variable that stores the starting subtitle time, in milliseconds.
        ''' </param>
        ''' 
        ''' <param name="refEndTime">
        ''' A by-reference variable that stores the ending subtitle time, in milliseconds.
        ''' </param>
        ''' 
        ''' <param name="buffer">
        ''' The string buffer to store the the subtitle text.
        ''' </param>
        ''' 
        ''' <param name="refBufferLength">
        ''' A by-reference variable that indicates the length of <paramref name="buffer"/>.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' <see langword="True"/> if the operation success, otherwise, <see langword="False"/>.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="GetSubtitle", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Function GetSubtitleLine(<MarshalAs(UnmanagedType.I4)> ByVal lineIndex As Integer,
                                               <MarshalAs(UnmanagedType.I4)> ByRef refStartTime As Integer,
                                               <MarshalAs(UnmanagedType.I4)> ByRef refEndTime As Integer,
                                               <MarshalAs(UnmanagedType.LPStr)> ByVal buffer As StringBuilder,
                                               <MarshalAs(UnmanagedType.I4)> ByRef refBufferLength As Integer
        ) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Sets an absolute delay on the current subtitle file.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="time">
        ''' The delay, in milliseconds.
        ''' </param>
        ''' 
        ''' <param name="fromLineIndex">
        ''' The starting subtitle line index.
        ''' </param>
        ''' 
        ''' <param name="toLineIndex">
        ''' The ending subtitle line index.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' <see langword="True"/> if the operation success, otherwise, <see langword="False"/>.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="SetAbsoluteDelay", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Function SetAbsoluteDelay(
                <MarshalAs(UnmanagedType.I4)> ByVal time As Integer,
                <MarshalAs(UnmanagedType.I4)> ByVal fromLineIndex As Integer,
                <MarshalAs(UnmanagedType.I4)> ByVal toLineIndex As Integer
        ) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Gets the playback delay of the current subtitle file.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' The playback delay, in milliseconds.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="GetPlaybackDelay", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Function GetPlaybackDelay(
        ) As <MarshalAs(UnmanagedType.I4)> Integer
        End Function

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Sets a playback delay on the current subtitle file.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="time">
        ''' The playback delay, in milliseconds.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="SetPlaybackDelay", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Sub SetPlaybackDelay(<MarshalAs(UnmanagedType.I4)> ByVal time As Integer)
        End Sub

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Adds a subtitle line at the specified time in the current subtitle file. 
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="startTime">
        ''' The starting subtitle time, in milliseconds.
        ''' </param>
        ''' 
        ''' <param name="endTime">
        ''' The ending subtitle time, in milliseconds.
        ''' </param>
        ''' 
        ''' <param name="text">
        ''' The subtitle text.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' 
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="AddSubtitle", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Function AddSubtitleLine(<MarshalAs(UnmanagedType.I4)> ByVal startTime As Integer,
                                               <MarshalAs(UnmanagedType.I4)> ByVal endTime As Integer,
                                               <MarshalAs(UnmanagedType.LPStr)> ByVal text As String
        ) As <MarshalAs(UnmanagedType.I4)> Integer
        End Function

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Adds a subtitle line at the specified time in the current subtitle file. 
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="lineIndex">
        ''' The index of the line where to insert the subtitle line.
        ''' </param>
        ''' 
        ''' <param name="startTime">
        ''' The starting subtitle time, in milliseconds.
        ''' </param>
        ''' 
        ''' <param name="endTime">
        ''' The ending subtitle time, in milliseconds.
        ''' </param>
        ''' 
        ''' <param name="text">
        ''' The subtitle text.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' <see langword="True"/> if the operation success, otherwise, <see langword="False"/>.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="InsertSubtitle", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Function InsertSubtitleLine(<MarshalAs(UnmanagedType.I4)> ByVal lineIndex As Integer,
                                                  <MarshalAs(UnmanagedType.I4)> ByVal endTime As Integer,
                                                  <MarshalAs(UnmanagedType.I4)> ByVal startTime As Integer,
                                                  <MarshalAs(UnmanagedType.LPStr)> ByVal text As String
        ) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Removes a subtitle line in the current subtitle file. 
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="lineIndex">
        ''' The index of the subtitle line to remove.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <returns>
        ''' <see langword="True"/> if the operation success, otherwise, <see langword="False"/>.
        ''' </returns>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="DeleteSubtitle", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Function DeleteSubtitleLine(<MarshalAs(UnmanagedType.I4)> ByVal lineIndex As Integer
        ) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Clears all the subtitle lines in the current subtitle file. 
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="ClearSubtitles", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Sub ClearSubtitleLines()
        End Sub

        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Create a new subtitle. 
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        <SuppressUnmanagedCodeSecurity>
        <DllImport("SubtitleAPI.dll", EntryPoint:="CreateNewSubtitle", SetLastError:=False, CharSet:=CharSet.Ansi)>
        Friend Shared Sub CreateNewSubtitleLine()
        End Sub

#End Region

    End Class

End Namespace

#End Region