UTF32Encoding::GetChars Method (array<Byte>^, Int32, Int32, array<Char>^, Int32)
Decodes a sequence of bytes from the specified byte array into the specified character array.
Assembly: mscorlib (in mscorlib.dll)
public: virtual int GetChars( array<unsigned char>^ bytes, int byteIndex, int byteCount, array<wchar_t>^ chars, int charIndex ) override
Parameters
- bytes
-
Type:
array<System::Byte>^
The byte array containing the sequence of bytes to decode.
- byteIndex
-
Type:
System::Int32
The index of the first byte to decode.
- byteCount
-
Type:
System::Int32
The number of bytes to decode.
- chars
-
Type:
array<System::Char>^
The character array to contain the resulting set of characters.
- charIndex
-
Type:
System::Int32
The index at which to start writing the resulting set of characters.
| Exception | Condition |
|---|---|
| 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 (see Character Encoding in the .NET Framework for complete explanation) -and- DecoderFallback is set to DecoderExceptionFallback. |
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.
The following example encodes a string into an array of bytes, and then decodes the bytes into an array of characters.
using namespace System; using namespace System::Text; void PrintCountsAndChars( array<Byte>^bytes, Encoding^ enc ); int main() { // Create two instances of UTF32Encoding: one with little-endian byte order and one with big-endian byte order. UTF32Encoding^ u32LE = gcnew UTF32Encoding( false,true,true ); UTF32Encoding^ u32BE = gcnew 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) String^ myStr = L"za\u0306\u01FD\u03B2\xD8FF\xDCFF"; // barrBE uses the big-endian byte order. array<Byte>^barrBE = gcnew array<Byte>(u32BE->GetByteCount( myStr )); u32BE->GetBytes( myStr, 0, myStr->Length, barrBE, 0 ); // barrLE uses the little-endian byte order. array<Byte>^barrLE = gcnew array<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 ); } } void PrintCountsAndChars( array<Byte>^bytes, Encoding^ enc ) { // Display the name of the encoding used. Console::Write( "{0,-25} :", enc ); // 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. array<Char>^chars = gcnew array<Char>(iCC); enc->GetChars( bytes, 0, bytes->Length, chars, 0 ); Console::WriteLine( chars ); } /* This code produces the following output. The question marks take the place of characters that cannot be displayed at the console. BE array with BE encoding : System.Text.UTF32Encoding : 7 14 :za??�? LE array with LE encoding : System.Text.UTF32Encoding : 7 14 :za??�? BE array with LE encoding : System.Text.UTF32Encoding :Invalid byte was found at byte index 3. LE array with BE encoding : System.Text.UTF32Encoding :Invalid byte was found at byte index 3. */
Available since 10
.NET Framework
Available since 2.0