Olvasás angol nyelven Szerkesztés

Megosztás a következőn keresztül:


UTF32Encoding.GetChars Method

Definition

Decodes a sequence of bytes into a set of characters.

Overloads

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(Byte*, Int32, Char*, Int32)

Source:
UTF32Encoding.cs
Source:
UTF32Encoding.cs
Source:
UTF32Encoding.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.

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

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

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

Attributes

Exceptions

bytes is null.

-or-

chars is null.

byteCount or charCount is less than zero.

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

-or-

charCount is less than the resulting number of characters.

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 a ArgumentException. 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, the application uses the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively.

See also

Applies to

.NET 9 és más verziók
Termék Verziók
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 1.3, 1.4, 1.6, 2.0, 2.1
UWP 10.0

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

Source:
UTF32Encoding.cs
Source:
UTF32Encoding.cs
Source:
UTF32Encoding.cs

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

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

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

The actual number of characters written into chars.

Exceptions

bytes is null.

-or-

chars is null.

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.

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.

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

-and-

DecoderFallback is set to DecoderExceptionFallback.

Examples

The following example encodes a string into an array of bytes, and then decodes the bytes into an array of characters.

using System;
using System.Text;

public class SamplesUTF32Encoding  {

   public static void Main()  {

      // Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order.
      UTF32Encoding u32LE = new UTF32Encoding( false, true, true );
      UTF32Encoding u32BE = new UTF32Encoding( true, true, true );

      // Create byte arrays from the same string containing the following characters:
      //    Latin Small Letter Z (U+007A)
      //    Latin Small Letter A (U+0061)
      //    Combining Breve (U+0306)
      //    Latin Small Letter AE With Acute (U+01FD)
      //    Greek Small Letter Beta (U+03B2)
      //    a high-surrogate value (U+D8FF)
      //    a low-surrogate value (U+DCFF)
      String myStr = "za\u0306\u01FD\u03B2\uD8FF\uDCFF";

      // barrBE uses the big-endian byte order.
      byte[] barrBE = new byte[u32BE.GetByteCount( myStr )];
      u32BE.GetBytes( myStr, 0, myStr.Length, barrBE, 0 );

      // barrLE uses the little-endian byte order.
      byte[] barrLE = new byte[u32LE.GetByteCount( myStr )];
      u32LE.GetBytes( myStr, 0, myStr.Length, barrLE, 0 );

      // Get the char counts and decode the byte arrays.
      Console.Write( "BE array with BE encoding : " );
      PrintCountsAndChars( barrBE, u32BE );
      Console.Write( "LE array with LE encoding : " );
      PrintCountsAndChars( barrLE, u32LE );

      // Decode the byte arrays using an encoding with a different byte order.
      Console.Write( "BE array with LE encoding : " );
      try  {
         PrintCountsAndChars( barrBE, u32LE );
      }
      catch ( System.ArgumentException e )  {
         Console.WriteLine( e.Message );
      }

      Console.Write( "LE array with BE encoding : " );
      try  {
         PrintCountsAndChars( barrLE, u32BE );
      }
      catch ( System.ArgumentException e )  {
         Console.WriteLine( e.Message );
      }
   }

   public static void PrintCountsAndChars( byte[] bytes, Encoding enc )  {

      // Display the name of the encoding used.
      Console.Write( "{0,-25} :", enc.ToString() );

      // Display the exact character count.
      int iCC  = enc.GetCharCount( bytes );
      Console.Write( " {0,-3}", iCC );

      // Display the maximum character count.
      int iMCC = enc.GetMaxCharCount( bytes.Length );
      Console.Write( " {0,-3} :", iMCC );

      // Decode the bytes and display the characters.
      char[] chars = new char[iCC];
      enc.GetChars( bytes, 0, bytes.Length, chars, 0 );
      Console.WriteLine( chars );
   }
}

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 a ArgumentException. 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, the application uses the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively.

See also

Applies to

.NET 9 és más verziók
Termék Verziók
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 1.3, 1.4, 1.6, 2.0, 2.1
UWP 10.0