UTF8Encoding.GetChars Method

Definition

Namespace:

System.Text

Assembly:

System.Text.Encoding.Extensions.dll

Decodes a sequence of bytes into a set of characters.

Overloads

GetChars(ReadOnlySpan<Byte>, Span<Char>)	Decodes the specified byte span into the specified character span.
GetChars(Byte*, Int32, Char*, Int32)	Decodes a sequence of bytes starting at the specified byte pointer into a set of characters that are stored starting at the specified character pointer.
GetChars(Byte[], Int32, Int32, Char[], Int32)	Decodes a sequence of bytes from the specified byte array into the specified character array.

GetChars(ReadOnlySpan<Byte>, Span<Char>)

Source:

UTF8Encoding.cs

Decodes the specified byte span into the specified character span.

public:
 override int GetChars(ReadOnlySpan<System::Byte> bytes, Span<char> chars);

public override int GetChars (ReadOnlySpan<byte> bytes, Span<char> chars);

override this.GetChars : ReadOnlySpan<byte> * Span<char> -> int

Public Overrides Function GetChars (bytes As ReadOnlySpan(Of Byte), chars As Span(Of Char)) As Integer

Parameters

bytes

ReadOnlySpan<Byte>

The span containing the bytes to decode.

chars

Span<Char>

The span to contain the resulting set of characters.

Returns

Int32

The actual number of characters written into chars.

Remarks

To calculate the exact size required by GetChars to store the resulting characters, call the GetCharCount method. To calculate the maximum size, call the GetMaxCharCount method. The GetCharCount method generally allocates less memory, while the GetMaxCharCount method generally executes faster.

With error detection, an invalid sequence causes this method to throw an ArgumentException exception. Without error detection, invalid sequences are ignored, and no exception is thrown.

If the set of bytes to be decoded includes the byte order mark (BOM) and the span of bytes was returned by a method of a non-BOM aware type, the character U+FFFE is included in the span of characters returned by this method. You can remove it by calling the String.TrimStart method.

Data to be converted, such as data read from a stream, might be available only in sequential blocks. In this case, or if the amount of data is so large that it needs to be divided into smaller blocks, use the Decoder or the Encoder object provided by the GetDecoder method or the GetEncoder method, respectively.

GetChars(Byte*, Int32, Char*, Int32)

Source:

UTF8Encoding.cs

Important

This API is not CLS-compliant.

Decodes a sequence of bytes starting at the specified byte pointer into a set of characters that are stored starting at the specified character pointer.

public:
 override int GetChars(System::Byte* bytes, int byteCount, char* chars, int charCount);

[System.CLSCompliant(false)]
public override int GetChars (byte* bytes, int byteCount, char* chars, int charCount);

[<System.CLSCompliant(false)>]
override this.GetChars : nativeptr<byte> * int * nativeptr<char> * int -> int

Parameters

bytes

Byte*

A pointer to the first byte to decode.

byteCount

Int32

The number of bytes to decode.

chars

Char*

A pointer to the location at which to start writing the resulting set of characters.

charCount

Int32

The maximum number of characters to write.

Returns

Int32

The actual number of characters written at the location indicated by chars.

Attributes

CLSCompliantAttribute

Exceptions

ArgumentNullException

bytes is null.

-or-

chars is null.

ArgumentOutOfRangeException

byteCount or charCount is less than zero.

ArgumentException

Error detection is enabled, and bytes contains an invalid sequence of bytes.

-or-

charCount is less than the resulting number of characters.

DecoderFallbackException

A fallback occurred (for more information, see Character Encoding in .NET)

-and-

DecoderFallback is set to DecoderExceptionFallback.

Remarks

To calculate the exact array size required by GetChars to store the resulting characters, call the GetCharCount method. To calculate the maximum array size, call the GetMaxCharCount method. The GetCharCount method generally allocates less memory, while the GetMaxCharCount method generally executes faster.

With error detection, an invalid sequence causes this method to throw an ArgumentException exception. Without error detection, invalid sequences are ignored, and no exception is thrown.

If the range of bytes to be decoded includes the byte order mark (BOM) and the byte array was returned by a method of a non-BOM aware type, the character U+FFFE is included in the character array returned by this method. You can remove it by calling the String.TrimStart method.

Data to be converted, such as data read from a stream, might be available only in sequential blocks. In this case, or if the amount of data is so large that it needs to be divided into smaller blocks, use the Decoder or the Encoder object provided by the GetDecoder method or the GetEncoder method, respectively.

See also

• GetCharCount(Byte[], Int32, Int32)
• GetMaxCharCount(Int32)
• GetDecoder()
• GetString(Byte[], Int32, Int32)

GetChars(Byte[], Int32, Int32, Char[], Int32)

Source:

UTF8Encoding.cs

Decodes a sequence of bytes from the specified byte array into the specified character array.

public:
 override int GetChars(cli::array <System::Byte> ^ bytes, int byteIndex, int byteCount, cli::array <char> ^ chars, int charIndex);

public override int GetChars (byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex);

override this.GetChars : byte[] * int * int * char[] * int -> int

Public Overrides Function GetChars (bytes As Byte(), byteIndex As Integer, byteCount As Integer, chars As Char(), charIndex As Integer) As Integer

Parameters

bytes

Byte[]

The byte array containing the sequence of bytes to decode.

byteIndex

Int32

The index of the first byte to decode.

byteCount

Int32

The number of bytes to decode.

chars

Char[]

The character array to contain the resulting set of characters.

charIndex

Int32

The index at which to start writing the resulting set of characters.

Returns

Int32

The actual number of characters written into chars.

Exceptions

ArgumentNullException

bytes is null.

-or-

chars is null.

ArgumentOutOfRangeException

byteIndex or byteCount or charIndex is less than zero.

-or-

byteindex and byteCount do not denote a valid range in bytes.

-or-

charIndex is not a valid index in chars.

ArgumentException

Error detection is enabled, and bytes contains an invalid sequence of bytes.

-or-

chars does not have enough capacity from charIndex to the end of the array to accommodate the resulting characters.

DecoderFallbackException

A fallback occurred (for more information, see Character Encoding in .NET)

-and-

DecoderFallback is set to DecoderExceptionFallback.

Examples

The following example uses the GetChars method to decode a range of elements in a byte array and store the result in a character array.

using namespace System;
using namespace System::Text;
using namespace System::Collections;
int main()
{
   array<Char>^chars;
   array<Byte>^bytes = {85,84,70,56,32,69,110,99,111,100,105,110,103,32,69,120,97,109,112,108,101};
   UTF8Encoding^ utf8 = gcnew UTF8Encoding;
   int charCount = utf8->GetCharCount( bytes, 2, 13 );
   chars = gcnew array<Char>(charCount);
   int charsDecodedCount = utf8->GetChars( bytes, 2, 13, chars, 0 );
   Console::WriteLine( "{0} characters used to decode bytes.", charsDecodedCount );
   Console::Write( "Decoded chars: " );
   IEnumerator^ myEnum = chars->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Char c = safe_cast<Char>(myEnum->Current);
      Console::Write( "[{0}]", c.ToString() );
   }

   Console::WriteLine();
}

using System;
using System.Text;

class UTF8EncodingExample {
    public static void Main() {
        Char[] chars;
        Byte[] bytes = new Byte[] {
             85,  84,  70,  56,  32,  69, 110,
             99, 111, 100, 105, 110, 103,  32,
             69, 120,  97, 109, 112, 108, 101
        };

        UTF8Encoding utf8 = new UTF8Encoding();

        int charCount = utf8.GetCharCount(bytes, 2, 13);
        chars = new Char[charCount];
        int charsDecodedCount = utf8.GetChars(bytes, 2, 13, chars, 0);

        Console.WriteLine(
            "{0} characters used to decode bytes.", charsDecodedCount
        );

        Console.Write("Decoded chars: ");
        foreach (Char c in chars) {
            Console.Write("[{0}]", c);
        }
        Console.WriteLine();
    }
}

Imports System.Text

Class UTF8EncodingExample
    
    Public Shared Sub Main()
        Dim chars() As Char
        Dim bytes() As Byte = { _
            85,  84,  70,  56,  32,  69, 110, _
            99, 111, 100, 105, 110, 103,  32, _
            69, 120,  97, 109, 112, 108, 101 _
        }
        
        Dim utf8 As New UTF8Encoding()
        
        Dim charCount As Integer = utf8.GetCharCount(bytes, 2, 13)
        chars = New Char(charCount - 1) {}
        Dim charsDecodedCount As Integer = utf8.GetChars(bytes, 2, 13, chars, 0)
        
        Console.WriteLine("{0} characters used to decode bytes.", charsDecodedCount)
        
        Console.Write("Decoded chars: ")
        Dim c As Char
        For Each c In  chars
            Console.Write("[{0}]", c)
        Next c
        Console.WriteLine()
    End Sub
End Class

Remarks

To calculate the exact array size required by GetChars to store the resulting characters, call the GetCharCount method. To calculate the maximum array size, call the GetMaxCharCount method. The GetCharCount method generally allocates less memory, while the GetMaxCharCount method generally executes faster.

With error detection, an invalid sequence causes this method to throw an ArgumentException exception. Without error detection, invalid sequences are ignored, and no exception is thrown.

If the range of bytes to be decoded includes the byte order mark (BOM) and the byte array was returned by a method of a non-BOM aware type, the character U+FFFE is included in the character array returned by this method. You can remove it by calling the String.TrimStart method.

Data to be converted, such as data read from a stream, might be available only in sequential blocks. In this case, or if the amount of data is so large that it needs to be divided into smaller blocks, use the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively.

See also

• GetCharCount(Byte[], Int32, Int32)
• GetMaxCharCount(Int32)
• GetDecoder()
• GetString(Byte[], Int32, Int32)