Decoder.Convert Methode

public:
 virtual void Convert(ReadOnlySpan<System::Byte> bytes, Span<char> chars, bool flush, [Runtime::InteropServices::Out] int % bytesUsed, [Runtime::InteropServices::Out] int % charsUsed, [Runtime::InteropServices::Out] bool % completed);

public virtual void Convert(ReadOnlySpan<byte> bytes, Span<char> chars, bool flush, out int bytesUsed, out int charsUsed, out bool completed);

abstract member Convert : ReadOnlySpan<byte> * Span<char> * bool * int * int * bool -> unit
override this.Convert : ReadOnlySpan<byte> * Span<char> * bool * int * int * bool -> unit

Public Overridable Sub Convert (bytes As ReadOnlySpan(Of Byte), chars As Span(Of Char), flush As Boolean, ByRef bytesUsed As Integer, ByRef charsUsed As Integer, ByRef completed As Boolean)

Parameters

Opmerkingen

De completed uitvoerparameter geeft aan of alle gegevens in het bereik van invoerbytes zijn geconverteerd en opgeslagen in de tekenbereiken. Deze parameter wordt ingesteld op false als het aantal bytes in het bereik van invoerbytes niet kan worden geconverteerd zonder het aantal tekens in de tekenreeksen te overschrijden. In dat geval moet de toepassing de inhoud van de uitvoerbuffer gebruiken of een nieuwe uitvoerbuffer opgeven, de bytes parameter verhogen met het aantal bytes dat is opgegeven door de bytesUsed parameter en vervolgens de Convert methode opnieuw aanroepen om de resterende invoer te verwerken.

De completed parameter kan ook worden ingesteld op false, ook al zijn de parameter en de lengte van de bytesUsed bytes-spanlengte gelijk. Deze situatie treedt op als er nog steeds gegevens zijn in het Decoder object dat niet in de bytes periode is opgeslagen.

public:
 virtual void Convert(System::Byte* bytes, int byteCount, char* chars, int charCount, bool flush, [Runtime::InteropServices::Out] int % bytesUsed, [Runtime::InteropServices::Out] int % charsUsed, [Runtime::InteropServices::Out] bool % completed);

[System.CLSCompliant(false)]
[System.Runtime.InteropServices.ComVisible(false)]
public virtual void Convert(byte* bytes, int byteCount, char* chars, int charCount, bool flush, out int bytesUsed, out int charsUsed, out bool completed);

[System.CLSCompliant(false)]
[System.Runtime.InteropServices.ComVisible(false)]
[System.Security.SecurityCritical]
public virtual void Convert(byte* bytes, int byteCount, char* chars, int charCount, bool flush, out int bytesUsed, out int charsUsed, out bool completed);

[System.CLSCompliant(false)]
public virtual void Convert(byte* bytes, int byteCount, char* chars, int charCount, bool flush, out int bytesUsed, out int charsUsed, out bool completed);

[<System.CLSCompliant(false)>]
[<System.Runtime.InteropServices.ComVisible(false)>]
abstract member Convert : nativeptr<byte> * int * nativeptr<char> * int * bool * int * int * bool -> unit
override this.Convert : nativeptr<byte> * int * nativeptr<char> * int * bool * int * int * bool -> unit

[<System.CLSCompliant(false)>]
[<System.Runtime.InteropServices.ComVisible(false)>]
[<System.Security.SecurityCritical>]
abstract member Convert : nativeptr<byte> * int * nativeptr<char> * int * bool * int * int * bool -> unit
override this.Convert : nativeptr<byte> * int * nativeptr<char> * int * bool * int * int * bool -> unit

[<System.CLSCompliant(false)>]
abstract member Convert : nativeptr<byte> * int * nativeptr<char> * int * bool * int * int * bool -> unit
override this.Convert : nativeptr<byte> * int * nativeptr<char> * int * bool * int * int * bool -> unit

Parameters

Kenmerken

CLSCompliantAttribute ComVisibleAttribute SecurityCriticalAttribute

Uitzonderingen

Opmerkingen

De completed uitvoerparameter geeft aan of alle gegevens in de invoerbuffer zijn geconverteerd en opgeslagen in de uitvoerbuffer. Deze parameter wordt ingesteld op false als het aantal bytes dat is opgegeven door de byteCount parameter niet kan worden geconverteerd zonder het aantal tekens te overschrijden dat is opgegeven door de charCount parameter. In dat geval moet de toepassing de inhoud van de uitvoerbuffer gebruiken of een nieuwe uitvoerbuffer opgeven, de bytes parameter verhogen met het aantal bytes dat is opgegeven door de bytesUsed parameter en vervolgens de Convert methode opnieuw aanroepen om de resterende invoer te verwerken.

De completed parameter kan ook worden ingesteld op false, ook al zijn de bytesUsed parameters byteCount gelijk. Deze situatie treedt op als er nog steeds gegevens zijn in het Decoder object dat niet in de bytes buffer is opgeslagen.

public:
 virtual void Convert(cli::array <System::Byte> ^ bytes, int byteIndex, int byteCount, cli::array <char> ^ chars, int charIndex, int charCount, bool flush, [Runtime::InteropServices::Out] int % bytesUsed, [Runtime::InteropServices::Out] int % charsUsed, [Runtime::InteropServices::Out] bool % completed);

public virtual void Convert(byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex, int charCount, bool flush, out int bytesUsed, out int charsUsed, out bool completed);

[System.Runtime.InteropServices.ComVisible(false)]
public virtual void Convert(byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex, int charCount, bool flush, out int bytesUsed, out int charsUsed, out bool completed);

abstract member Convert : byte[] * int * int * char[] * int * int * bool * int * int * bool -> unit
override this.Convert : byte[] * int * int * char[] * int * int * bool * int * int * bool -> unit

[<System.Runtime.InteropServices.ComVisible(false)>]
abstract member Convert : byte[] * int * int * char[] * int * int * bool * int * int * bool -> unit
override this.Convert : byte[] * int * int * char[] * int * int * bool * int * int * bool -> unit

Public Overridable Sub Convert (bytes As Byte(), byteIndex As Integer, byteCount As Integer, chars As Char(), charIndex As Integer, charCount As Integer, flush As Boolean, ByRef bytesUsed As Integer, ByRef charsUsed As Integer, ByRef completed As Boolean)

Parameters

Kenmerken

ComVisibleAttribute

Uitzonderingen

Voorbeelden

In het volgende voorbeeld wordt de Convert methode gebruikt om een bestand met UTF-16 tekens te converteren naar UTF-8. Vervolgens wordt de Convert methode gebruikt om de UTF-8 tekens terug te zetten naar UTF-16 tekens.

// This code example demonstrates the Encoder.Convert() and Decoder.Convert methods.
// This example uses files for input and output, but any source that can be expressed
// as a stream can be used instead.

    using System;
    using System.Text;
    using System.IO;

    public class Sample
    {
    static void Main(string[] args)
        {
// Create a large file of UTF-16 encoded Unicode characters. The file is named Example.txt,
// and is used as input to the Encoder.Convert() method.

            CreateTestFile("Example.txt");

// Using an input file of UTF-16 encoded characters named Example.txt, create an output file
// of UTF-8 encoded bytes named UTF8.txt.

            EncoderConvert("Example.txt", "UTF8.txt", Encoding.UTF8);

// Using an input file of UTF-8 encoded bytes named UTF8.txt, create an output file
// of UTF-16 encoded characters named UTF16.txt.

            DecoderConvert("UTF8.txt", "UTF16.txt", Encoding.UTF8);
        }

// --------------------------------------------------------------------------------------------
// Use the Encoder.Convert() method to convert a file of characters to a file of encoded bytes.
// --------------------------------------------------------------------------------------------
        static void EncoderConvert(String inputFileName, String outputFileName, Encoding enc)
        {
// Convert an input file of characters to an output file of encoded bytes.
// StreamWriter could convert the input file for us, but we'll perform the conversion
// ourselves.

            FileStream fs = new FileStream(outputFileName, FileMode.Create);
            BinaryWriter outputFile = new BinaryWriter(fs);

// StreamReader will detect Unicode encoding from the Byte Order Mark that heads the input file.
            StreamReader inputFile = new StreamReader(inputFileName);

// Get an Encoder.
            Encoder encoder = enc.GetEncoder();

// Guarantee the output buffer large enough to convert a few characters.
            int UseBufferSize = 64;
            if (UseBufferSize < enc.GetMaxByteCount(10))
                    UseBufferSize = enc.GetMaxByteCount(10);
            byte[] bytes = new byte[UseBufferSize];

// Intentionally make the input character buffer larger than the output byte buffer so the
// conversion loop executes more than one cycle.

            char[] chars = new char[UseBufferSize * 4];
            int charsRead;
            do
            {
// Read at most the number of characters that will fit in the input buffer. The return
// value is the actual number of characters read, or zero if no characters remain.
                charsRead = inputFile.Read(chars, 0, UseBufferSize * 4);

                bool completed = false;
                int charIndex = 0;
                int charsUsed;
                int bytesUsed;

                while (!completed)
                {
// If this is the last input data, flush the encoder's internal buffer and state.

                    bool flush = (charsRead == 0);
                    encoder.Convert(chars, charIndex, charsRead - charIndex,
                                    bytes, 0, UseBufferSize, flush,
                                    out charsUsed, out bytesUsed, out completed);

// The conversion produced the number of bytes indicated by bytesUsed. Write that number
// of bytes to the output file.
                    outputFile.Write(bytes, 0, bytesUsed);

// Increment charIndex to the next block of characters in the input buffer, if any, to convert.
                    charIndex += charsUsed;
                }
            }
            while(charsRead != 0);

            outputFile.Close();
            fs.Close();
            inputFile.Close();
        }

// --------------------------------------------------------------------------------------------
// Use the Decoder.Convert() method to convert a file of encoded bytes to a file of characters.
// --------------------------------------------------------------------------------------------
        static void DecoderConvert(String inputFileName, String outputFileName, Encoding enc)
        {
// Convert an input file of of encoded bytes to an output file characters.
// StreamWriter could convert the input file for us, but we'll perform the conversion
// ourselves.

            StreamWriter outputFile = new StreamWriter(outputFileName, false, Encoding.Unicode);

// Read the input as a binary file so we can detect the Byte Order Mark.
            FileStream fs = new FileStream(inputFileName, FileMode.Open);
            BinaryReader inputFile = new BinaryReader(fs);

// Get a Decoder.
            Decoder decoder = enc.GetDecoder();

// Guarantee the output buffer large enough to convert a few characters.
            int UseBufferSize = 64;
            if (UseBufferSize < enc.GetMaxCharCount(10))
                    UseBufferSize = enc.GetMaxCharCount(10);
            char[] chars = new char[UseBufferSize];

// Intentionally make the input byte buffer larger than the output character buffer so the
// conversion loop executes more than one cycle.

            byte[] bytes = new byte[UseBufferSize * 4];
            int bytesRead;
            do
            {
// Read at most the number of bytes that will fit in the input buffer. The
// return value is the actual number of bytes read, or zero if no bytes remain.

                bytesRead = inputFile.Read(bytes, 0, UseBufferSize * 4);

                bool completed = false;
                int byteIndex = 0;
                int bytesUsed;
                int charsUsed;

                while (!completed)
                {
// If this is the last input data, flush the decoder's internal buffer and state.

                    bool flush = (bytesRead == 0);
                    decoder.Convert(bytes, byteIndex, bytesRead - byteIndex,
                                    chars, 0, UseBufferSize, flush,
                                    out bytesUsed, out charsUsed, out completed);

// The conversion produced the number of characters indicated by charsUsed. Write that number
// of characters to the output file.

                    outputFile.Write(chars, 0, charsUsed);

// Increment byteIndex to the next block of bytes in the input buffer, if any, to convert.
                    byteIndex += bytesUsed;
                }
            }
            while(bytesRead != 0);

            outputFile.Close();
            fs.Close();
            inputFile.Close();
        }

// --------------------------------------------------------------------------------------------
// Create a large file of UTF-16 encoded Unicode characters.
// --------------------------------------------------------------------------------------------
        static void CreateTestFile(String FileName)
        {
// StreamWriter defaults to UTF-8 encoding so explicitly specify Unicode, that is,
// UTF-16, encoding.
            StreamWriter file = new StreamWriter(FileName, false, Encoding.Unicode);

// Write a line of text 100 times.
            for (int i = 0; i < 100; i++)
            {
                file.WriteLine("This is an example input file used by the convert example.");
            }

// Write Unicode characters from U+0000 to, but not including, the surrogate character range.
            for (char c = (char)0; c < (char)0xD800; c++)
            {
                file.Write(c);
            }
            file.Close();
        }
    }

/*
This code example produces the following results:

(Execute the -dir- console window command and examine the files created.)

Example.txt, which contains 122,594 bytes (61,297 UTF-16 encoded characters).
UTF8.txt, which contains 169,712 UTF-8 encoded bytes.
UTF16.txt, which contains 122,594 bytes (61,297 UTF-16 encoded characters).

(Execute the -comp- console window command and compare the two Unicode files.)

>comp example.txt utf16.txt /L
Comparing example.txt and utf16.txt...
Files compare OK

(The two files are equal.)

*/

' This code example demonstrates the Encoder.Convert() and Decoder.Convert methods. 
' This example uses files for input and output, but any source that can be expressed
' as a stream can be used instead.

Imports System.Text
Imports System.IO

Public Class Sample
    Shared Sub Main(ByVal args() As String) 
        ' Create a large file of UTF-16 encoded Unicode characters. The file is named Example.txt, 
        ' and is used as input to the Encoder.Convert() method. 
        CreateTestFile("Example.txt")
        
        
        ' Using an input file of UTF-16 encoded characters named Example.txt, create an output file 
        ' of UTF-8 encoded bytes named UTF8.txt.
        EncoderConvert("Example.txt", "UTF8.txt", Encoding.UTF8)
        
        ' Using an input file of UTF-8 encoded bytes named UTF8.txt, create an output file 
        ' of UTF-16 encoded characters named UTF16.txt.
        DecoderConvert("UTF8.txt", "UTF16.txt", Encoding.UTF8)
    
    End Sub
    
    ' --------------------------------------------------------------------------------------------
    ' Use the Encoder.Convert() method to convert a file of characters to a file of encoded bytes.
    ' --------------------------------------------------------------------------------------------
    Shared Sub EncoderConvert(ByVal inputFileName As String, ByVal outputFileName As String, ByVal enc As Encoding) 
        ' Convert an input file of characters to an output file of encoded bytes.
        ' StreamWriter could convert the input file for us, but we'll perform the conversion 
        ' ourselves.
        Dim fs As New FileStream(outputFileName, FileMode.Create)
        Dim outputFile As New BinaryWriter(fs)
        
        ' StreamReader will detect Unicode encoding from the Byte Order Mark that heads the input file.
        Dim inputFile As New StreamReader(inputFileName)
        
        ' Get an Encoder.
        Dim encoder As Encoder = enc.GetEncoder()
        
        ' Guarantee the output buffer large enough to convert a few characters.
        Dim UseBufferSize As Integer = 64
        If UseBufferSize < enc.GetMaxByteCount(10) Then
            UseBufferSize = enc.GetMaxByteCount(10)
        End If
        Dim bytes(UseBufferSize) As Byte
        
        ' Intentionally make the input character buffer larger than the output byte buffer so the 
        ' conversion loop executes more than one cycle. 
        Dim chars(UseBufferSize * 4) As Char
        Dim charsRead As Integer
        Do
            ' Read at most the number of characters that will fit in the input buffer. The return 
            ' value is the actual number of characters read, or zero if no characters remain. 
            charsRead = inputFile.Read(chars, 0, UseBufferSize * 4)
            
            Dim completed As Boolean = False
            Dim charIndex As Integer = 0
            Dim charsUsed As Integer
            Dim bytesUsed As Integer
            
            While Not completed
                ' If this is the last input data, flush the encoder's internal buffer and state.
                Dim flush As Boolean = charsRead = 0
                encoder.Convert(chars, charIndex, charsRead - charIndex, bytes, 0, UseBufferSize, flush, charsUsed, bytesUsed, completed)
                
                ' The conversion produced the number of bytes indicated by bytesUsed. Write that number
                ' of bytes to the output file.
                outputFile.Write(bytes, 0, bytesUsed)
                
                ' Increment charIndex to the next block of characters in the input buffer, if any, to convert.
                charIndex += charsUsed
            End While
        Loop While charsRead <> 0
        
        outputFile.Close()
        fs.Close()
        inputFile.Close()
    
    End Sub
    
    ' --------------------------------------------------------------------------------------------
    ' Use the Decoder.Convert() method to convert a file of encoded bytes to a file of characters.
    ' --------------------------------------------------------------------------------------------
    Shared Sub DecoderConvert(ByVal inputFileName As String, ByVal outputFileName As String, ByVal enc As Encoding) 
        ' Convert an input file of of encoded bytes to an output file characters.
        ' StreamWriter could convert the input file for us, but we'll perform the conversion 
        ' ourselves.
        Dim outputFile As New StreamWriter(outputFileName, False, Encoding.Unicode)
        
        ' Read the input as a binary file so we can detect the Byte Order Mark.
        Dim fs As New FileStream(inputFileName, FileMode.Open)
        Dim inputFile As New BinaryReader(fs)
        
        ' Get a Decoder.
        Dim decoder As Decoder = enc.GetDecoder()
        
        ' Guarantee the output buffer large enough to convert a few characters.
        Dim UseBufferSize As Integer = 64
        If UseBufferSize < enc.GetMaxCharCount(10) Then
            UseBufferSize = enc.GetMaxCharCount(10)
        End If
        Dim chars(UseBufferSize) As Char
        
        ' Intentionally make the input byte buffer larger than the output character buffer so the 
        ' conversion loop executes more than one cycle. 
        Dim bytes(UseBufferSize * 4) As Byte
        Dim bytesRead As Integer
        Do
            ' Read at most the number of bytes that will fit in the input buffer. The 
            ' return value is the actual number of bytes read, or zero if no bytes remain. 
            bytesRead = inputFile.Read(bytes, 0, UseBufferSize * 4)
            
            Dim completed As Boolean = False
            Dim byteIndex As Integer = 0
            Dim bytesUsed As Integer
            Dim charsUsed As Integer
            
            While Not completed
                ' If this is the last input data, flush the decoder's internal buffer and state.
                Dim flush As Boolean = bytesRead = 0
                decoder.Convert(bytes, byteIndex, bytesRead - byteIndex, chars, 0, UseBufferSize, flush, bytesUsed, charsUsed, completed)
                
                ' The conversion produced the number of characters indicated by charsUsed. Write that number
                ' of characters to the output file.
                outputFile.Write(chars, 0, charsUsed)
                
                ' Increment byteIndex to the next block of bytes in the input buffer, if any, to convert.
                byteIndex += bytesUsed
            End While
        Loop While bytesRead <> 0
        
        outputFile.Close()
        fs.Close()
        inputFile.Close()
    
    End Sub
    
    ' --------------------------------------------------------------------------------------------
    ' Create a large file of UTF-16 encoded Unicode characters. 
    ' --------------------------------------------------------------------------------------------
    Shared Sub CreateTestFile(ByVal FileName As String) 
        ' StreamWriter defaults to UTF-8 encoding so explicitly specify Unicode, that is, 
        ' UTF-16, encoding.
        Dim file As New StreamWriter(FileName, False, Encoding.Unicode)
        
        ' Write a line of text 100 times.
        Dim i As Integer
        For i = 0 To 99
            file.WriteLine("This is an example input file used by the convert example.")
        Next i
        
        ' Write Unicode characters from U+0000 to, but not including, the surrogate character range.
        Dim c As Integer
        For c = 0 To &HD800
            file.Write(ChrW(c))
        Next c
        file.Close()
    
    End Sub
End Class

'
'This code example produces the following results:
'
'(Execute the -dir- console window command and examine the files created.)
'
'Example.txt, which contains 122,594 bytes (61,297 UTF-16 encoded characters).
'UTF8.txt, which contains 169,712 UTF-8 encoded bytes.
'UTF16.txt, which contains 122,594 bytes (61,297 UTF-16 encoded characters).
'
'(Execute the -comp- console window command and compare the two Unicode files.)
'
'>comp example.txt utf16.txt /L
'Comparing example.txt and utf16.txt...
'Files compare OK
'
'(The two files are equal.)
'

Opmerkingen

De completed uitvoerparameter geeft aan of alle gegevens in de invoerbuffer zijn geconverteerd en opgeslagen in de uitvoerbuffer. Deze parameter wordt ingesteld op false als het aantal bytes dat is opgegeven door de byteCount parameter niet kan worden geconverteerd zonder het aantal tekens te overschrijden dat is opgegeven door de charCount parameter. In dat geval moet de toepassing de inhoud van de uitvoerbuffer gebruiken of een nieuwe uitvoerbuffer opgeven, de bytes parameter verhogen met het aantal bytes dat is opgegeven door de bytesUsed parameter en vervolgens de Convert methode opnieuw aanroepen om de resterende invoer te verwerken.

De completed parameter kan ook worden ingesteld op false, ook al zijn de bytesUsed parameters byteCount gelijk. Deze situatie treedt op als er nog steeds gegevens zijn in het Decoder object dat niet in de bytes buffer is opgeslagen.