RWUTF8Helper

Module:  Advanced Tools   Package:  Streams

Does not inherit

• Local Index
• Header File
• Description
• Static Global Functions

Non-Members

decodeFirstByte() decodeFourBytesEncoding()

decodeThreeBytesEncoding() decodeTwoBytesEncoding()

encodeOneUChar()

#include <rw/stream/RWUTF8Helper.h>

The class RWUTF8Helper provides common functionality used to encode and decode UTF-8 sequences.

static EncodingCategory 
decodeFirstByte(RWByte b);

Take s the first byte of a UTF-8 byte sequence encoding a single UTF-16 character, and returns the encoding category to which it belongs. Throws no exceptions.

Parameter List

b	The first byte of a UTF-8 byte sequence encoding a single UTF-16 character

static EncodingCategory 
decodeFourBytesEncoding(RWByte firstByte, RWByte secondByte,   
                        RWByte thirdByte, RWByte fourthByte,
                        RWUChar& highSurrogateValue, 
                        RWUChar& lowSurrogateValue);

Decodes a four-byte UTF-8 sequence. The function returns invalidUTF8Encoding in case the four-byte sequence doesn't represent a valid UTF-8 encoding sequence. Throws no exceptions.

Parameter List

firstByte	The first byte of a UTF-8 four-byte sequence encoding a single UTF-16 character.
secondByte	The second byte of a UTF-8 four-byte sequence encoding a single UTF-16 character.
thirdByte	The third byte of a UTF-8 four-byte sequence encoding a single UTF-16 character.
fourthByte	The fourth byte of a UTF-8 four-byte sequence encoding a single UTF-16 character.
highSurrogateValue	The UTF-16 high surrogate resulting from the decoding of the four-byte UTF-8 sequence.
lowSurrogateValue	The UTF-16 low surrogate resulting from the decoding of the four-byte UTF-8 sequence

static EncodingCategory 
decodeThreeBytesEncoding(RWByte firstByte, RWByte secondByte,
                         RWByte thirdByte, RWUChar& res);

Decodes a three-byte encoding UTF-8 sequence. The function returns invalidUTF8Encoding if the three-byte sequence doesn't represent a valid UTF-8 encoding sequence. Throws no exceptions.

Parameter List

firstByte	The first byte of a UTF-8 three-byte sequence encoding a single UTF-16 character.
secondByte	The second byte of a UTF-8 three-byte sequence encoding a single UTF-16 character.
thirdByte	The third byte of a UTF-8 three-byte sequence encoding a single UTF-16 character.
res	The UTF-16 character resulting from the decoding of the three-byte UTF-8 sequence

static EncodingCategory 
decodeTwoBytesEncoding(RWByte firstByte, RWByte secondByte,
                       RWUChar& res);

Decodes a two-byte encoding UTF-8 sequence. The function returns invalidUTF8Encoding in case the two-byte sequence doesn't represent a valid UTF-8 encoding sequence. Throws no exceptions.

Parameter List

firstByte	The first byte of a UTF-8 two-byte sequence encoding a single UTF-16 character.
secondByte	The second byte of a UTF-8 two-byte sequence encoding a single UTF-16 character.
res	The UTF-16 character resulting from the decoding of the two-byte UTF-8 sequence

static EncodingCategory 
encodeOneUChar(RWUChar uc, RWByte* res, 
               RWUChar highSurrogateValue= 0);

Encodes the UTF-16 character uc according to UTF-8. The function returns the UTF-8 encoding category that was used to convert the UTF-16 character, or an error if the UTF-16 character could not be transformed. Throws no exceptions.

Parameter List

uc	The UTF-16 character to be transformed.
res	A pointer to a byte array containing at least four bytes. The byte array is used to store the transformation result.
highSurrogateValue	This parameter is only used when a high surrogate was previously encountered.

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