UTF 8 ENCODING C CODE STANDARD HAS

Utf 8 Encoding C Code Standard Has

The multiplicity of the codes was necessary because the systems always considered that to one byte corresponded a single character. Following the internationalization coming with the Internet development, encoding management became more and more complex because of multilingual environments.Fortunately, The Unicode standard has successfully passed the challenge to gather every single characters from every encodings in one and only character tables: the Unicode character list.The Unicode format was born from the desire to unify the multitude of existing encoding. Each one have a consistent reason to be once you know the History of Encoding. And because the ISO-8859-7 (Greek) encoding considers that each of these two bytes is a character in itself in its mapping table.Note that the number of existing encodings is quite large.

Asian characters can be encoded for example using 4 bytes.Unfortunately there are several versions of the Unicode format depending on whether the number of bytes per character is fixed or dynamic, and depending on the order of reading bytes.We will only present the UTF-8 format because it tends to dominate because of its efficiency in terms of memory size and because of its backward compatibility with ASCII. The French “ é” for example is not at all useful for Greeks who also need to code a whole alphabet of their own.The Unicode solution is to get rid of the single byte limitation in order to have an almost infinite amount of possible characters. Some languages therefore needed their own extended ASCII code.

However, the Western Europe special characters are all coded on 2 bytes in UTF-8.=> It is for this reason that the accentuated characters are displayed on 2 characters instead of only one when the encoding is badly determined.You now know almost everything about UTF-8:– It has backward compatibility with ASCII– Special characters are stored on 2 to 4 bytes– Like any encoding, the application that “reads” the hexadecimal code must use the correct encodingYou only know “almost everything” because there is a specific feature in Unicode that still raises some compatibility issues: the BOM (Byte Mark Order). Somehow, it’s still as simple as it used to be: A “code” is always a single character in the character mapping.If an application can not read the UTF-8 or if it is forced in extended ASCII (as in our previous example on forcing in ISO-8859-7 in internet explorer) then the application will read each byte as one distinct character. It is encoded simply by respecting the UTF-8 character map. Only when special characters are used will the UTF-8 file be distinguished from ASCII.Special characters in UTF-8 are be stored in hexadecimal from 2 to 4 bytes.

And they do not do it so that they can focus on the language which they are interested in. As long as there is no special character outside the Windows-1252 table, most Windows applications do not encode texts using UTF-8.Thus, sending a Windows text file to a linux server or a proprietary application can easilylead to confusion.Because Unicode can encode all possible characters, it has become a nightmare for artists creating fonts because redrawing each character is an huge task. Moreover, it is impossible to know whether a text uses an ISO table or Windows table because they both correspond just to a sequence of bytes.This freedom taken by Microsoft would be less of a problem if Windows applications used UTF-8 by default but this is not the case. Thus, there may be some databases or applications or packages might have been programmed to receive a specific encoding and often enough they might be expecting a single byte per character.Microsoft took the liberty of creating its own character tables derived from ISO-8859-x tables.

This Byte Order Mark is neither standard nor mandatory but it makes it easier for compatible applications to determine the subtype of Unicode format and to define the direction for reading the bytes.This often causes compatibility issues because not all applications know how to handle the “BOM”.