sdk/samples/FrameworkSamples/CLR/EncodingApp/vb/encodingapp/encoderinfo.vb

   1
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   5 '  Copyright (C) Microsoft Corporation.  All rights reserved.
   6 '
   7 'This source code is intended only as a supplement to Microsoft
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  16 Imports System
  17 Imports System.Globalization
  18 Imports System.Text
  19
  20
  21 '/ <summary>
  22 '/ Class to encapsulate encoding options of Encoding type, Fallback mechanism and Normalization scheme
  23 '/ </summary>
  24
  25 Public Class EncoderInfo
  26     Public Shared NormalizationNone As String = "None"
  27     'Different fallback schemes
  28     Public Shared FallbackSchemes As String() =  {"Replacement", "Exception", "Best Fit"}
  29
  30     'Code page of encoding selected in options
  31     Private encodingCodePage As Integer = 0
  32
  33         'Encoding that we're using
  34         Private targetEncoding As Encoding = Encoding.Default
  35
  36     'EncoderFallback selected in options
  37     Private encFallback As EncoderFallback = EncoderFallback.ReplacementFallback
  38
  39     'Normalization scheme selected in options
  40     Private normalizationForm As String
  41
  42
  43     'Constructor initializing members to default values
  44     Public Sub New()
  45         'Initialize encoding to UTF8
  46         SetEncodingCodePage(Encoding.UTF8.CodePage)
  47
  48         'Initialize fallback scheme to replacement
  49         SetEncoderFallback(FallbackSchemes(0))
  50
  51         'Initialize normalization scheme to none
  52         SetNormalizationForm(NormalizationNone)
  53
  54     End Sub 'New
  55
  56     'Property to get the encoding scheme
  57
  58     Public ReadOnly Property CurrentEncoding() As Encoding
  59         Get
  60             Return Me.targetEncoding.Clone()
  61         End Get
  62     End Property
  63
  64
  65     'Method to set the code page of the selected encoding
  66     Public Sub SetEncodingCodePage(ByVal encodingCodePage As Integer)
  67         Me.encodingCodePage = encodingCodePage
  68         Me.targetEncoding = Encoding.GetEncoding(encodingCodePage, Me.encFallback, DecoderFallback.ReplacementFallback)
  69         If TypeOf Me.encFallback Is EncoderBestFitFallback Then
  70                 Dim bestFit As EncoderBestFitFallback = Me.encFallback
  71                 bestFit.ParentEncoding = Me.targetEncoding
  72         End If
  73     End Sub 'SetEncodingCodePage
  74
  75
  76     'Method to set the fallback scheme of the destination encoding
  77     Public Sub SetEncoderFallback(ByVal strFallback As String)
  78         ' Replacement
  79         If strFallback = FallbackSchemes(0) Then
  80             Me.encFallback = New EncoderReplacementFallback("?")
  81         Else ' Exception
  82             If strFallback = FallbackSchemes(1) Then
  83                 Me.encFallback = New EncoderExceptionFallback()
  84             Else
  85                 Me.encFallback = New EncoderBestFitFallback(Me.targetEncoding)
  86             End If
  87         End If
  88         Me.targetEncoding.EncoderFallback = Me.encFallback
  89
  90     End Sub 'SetEncoderFallback
  91
  92
  93     'Method to set the normalization scheme
  94     Public Sub SetNormalizationForm(ByVal strNormalization As String)
  95         normalizationForm = strNormalization
  96
  97     End Sub 'SetNormalizationForm
  98
  99
 100     'Method to normalize a given string in the normalization form specified
 101     Public Function GetNormalizedString(ByVal inputString As String) As String
 102         If normalizationForm <> NormalizationNone Then
 103             Dim n As NormalizationForm = CType([Enum].Parse(GetType(NormalizationForm), normalizationForm), NormalizationForm)
 104             'Normalize string
 105             inputString = inputString.Normalize(n)
 106         End If
 107
 108         Return inputString
 109
 110     End Function 'GetNormalizedString
 111 End Class 'EncoderInfo