Unique Features of Unicode
This section provides summary of unique features of the Unicode standard.
Comparing with other character coding standard, Unicode has the following unique
- Full 16-bit coding. Each code is 16-bit number. No restriction. None of the
16 bits is reserved for any special purposes.
- Big enough to handle all existing written languages and symbols. 16 bits gives
65536 code values. It can be expended to paired 16-bit codes to cover millions of
- Characters in the same language are coded in groups and ordered according their
natural sequence whenever it's possible.
- No escape sequences. No shift states.
- Common characters (letters) in languages are unified into code element. The biggest
example is the unification of Chinese/Japanese/Korean (CJK) ideographs into one common
set of code elements.
Another interesting feature of Unicode is the use of equivalent sequences.
Different sequences of code elements that represent the same
semantic value are called equivalent sequences.
For example, the small letter "a" and the circumflex accent "^"
can be represented by a single code element: U+00E2 (LATIN SMALL LETTER A WITH
CIRCUMFLEX). It can also be represented by a sequence of two code elements:
U+0302 (COMBINING CIRCUMFLEX ACCENT) and U+0061 (LATIN SMALL LETTER A). So U+00E2
and U+0302U+0061 are equivalent sequences. See the demonstration table below:
1. U+00E2 = â
2. U+0302U+0061 = ̂a
3. U+0061U+0302 = â
4. U+0061U+0302U+0062 = âb
5. U+0062U+0302U+0061 = b̂a
6. U+0062U+0302U+0066 = b̂b
The above table shows how a Web browser handles a sequence that has a "combining" element:
- The "combining" element will be combined with the next element or the previous
element depending on which element can accept the "combining" element,
see line 2, 3, 4 and 5 in the table.
- If both the next element and the previous element are not suitable for the "combining"
element, it will be forcibly combined with the next element,
see line 6 in the table.
Note that when send the same table to a PDF generation tool,
"combining" sequences may not be respected.
Table of Contents
About This Book
Character Sets and Encodings
ASCII Character Set and Encoding
GB2312 Character Set and Encoding
GB18030 Character Set and Encoding
JIS X0208 Character Set and Encodings
►Unicode Character Set
What Is Unicode?
Examples of Unicode Characters
►Unique Features of Unicode
Unicode Standard Releases
Code Point Blocks
Unicode 8.0 Character Samples
Unicode 7.0 Character Samples
Unicode 6.0 Character Samples
Unicode 5.0 Character Samples
Unicode 4.0 Character Samples
UTF-8 (Unicode Transformation Format - 8-Bit)
UTF-16, UTF-16BE and UTF-16LE Encodings
UTF-32, UTF-32BE and UTF-32LE Encodings
Java Language and Unicode Characters
Character Encoding in Java
Character Set Encoding Maps
Encoding Conversion Programs for Encoded Text Files
Using Notepad as a Unicode Text Editor
Using Microsoft Word as a Unicode Text Editor
Using Microsoft Excel as a Unicode Text Editor
Unicode Code Point Blocks - Code Charts
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