Class: ISO10646_to_UTF8 (in CharacterEncoderImplementations)

• Inheritance
• Description
• Class protocol
  • instance creation
  • queries
• Instance protocol
  • encoding & decoding
  • queries
  • stream support
• Examples

Inheritance:

   Object
   |
   +--CharacterEncoder
      |
      +--CharacterEncoderImplementations::VariableBytesEncoder
         |
         +--CharacterEncoderImplementations::ISO10646_to_UTF8
            |
            +--CharacterEncoderImplementations::ISO10646_to_UTF8_MAC
            |
            +--CharacterEncoderImplementations::ISO10646_to_XMLUTF8

Package:

stx:libbasic

Category:

Collections-Text-Encodings

Version:

rev: 1.31 date: 2018/01/19 13:43:21

user: stefan

file: CharacterEncoderImplementations__ISO10646_to_UTF8.st directory: libbasic

module: stx stc-classLibrary: libbasic

Description:

I can encode unicode characters into utf-8 and
decode utf-8 characters into unicode.

Notice the naming (many are confused):
    Unicode is the set of number-to-glyph assignments
whereas:
    UTF8 is a concrete way of xmitting Unicode codePoints (numbers).
UTF16 is another concrete encoding, for example.    
    
ST/X NEVER uses UTF8 internally - all characters are full 24bit characters.
Only when exchanging data, are these converted into UTF8 (or other) byte sequences.

Class protocol:

 flushSingleton

flushes the cached singleton

usage example(s):

self flushSingleton

 new

returns a singleton

 theOneAndOnlyInstance

returns a singleton

 bytesToReadFor: firstByte

Instance protocol:

 decodeString: aStringOrByteCollection

given a string in UTF8 encoding,
return a new string containing the same characters, in Unicode encoding.
Returns either a normal String, a Unicode16String or a Unicode32String instance.
This is only useful, when reading from external sources or communicating with
other systems
(ST/X never uses utf8 internally, but always uses strings of fully decoded unicode characters).
This only handles up-to 30bit characters.

 encodeString: aUnicodeString

return the UTF-8 representation of a Unicode string.
The resulting string is only useful to be stored on some external file,
not for being used inside ST/X.

 characterSize: charOrCodePoint

return the number of bytes required to encode codePoint

 nameOfEncoding

 encodeCharacter: aUnicodeCharacter on: aStream

given a character in unicode, encode it onto aStream.

 encodeString: aUnicodeString on: aStream

given a string in unicode, encode it onto aStream.

 readNext: charactersToReadArg charactersFrom: aStream

decode the next charactersToRead on aStream from utf-8 to unicode

 readNextCharacterFrom: aStream

decode the next character or byte on aStream from utf-8 to unicode

Examples: