UTF-8 character encoding

Thomas Wolff towo@towo.net
Tue Jun 26 21:39:00 GMT 2018


Am 25.06.2018 um 20:33 schrieb Lee:
> On 6/24/18, L A Walsh <cygwin@tlinx.org> wrote:
>> Lee wrote:
>>> So... keep it simple, set
>>>    LANG=en_US.UTF-8
>>> and use vi or something else that comes with cygwin to create the file
>>> and I'll have a file with UTF-8 character encoding - correct?
>> ---
>> 	The first 127 characters of UTF-8 are identical to the
>> first 127 characters of ASCII, and latin1 and iso-8859-1.
>>
>> If you don't use any characters that need accents or special symbols,
>> then nothing will be encoded in UTF-8, because its only
>> the characters OVER the first 127
>> (see chart @ http://www.babelstone.co.uk/Unicode/babelmap.html).
> I'm still trying to figure utf-8 out, but it seems to me that 0x0 -
> 0xff is part of the utf-8 encoding.  This chart makes things clearer
> ... at least for me :)
>      http://www.cl.cam.ac.uk/~mgk25/ucs/utf-8-history.txt
>   The proposed UCS transformation format encodes UCS values in the range
>   [0,0x7fffffff] using multibyte characters of lengths 1, 2, 3, 4, and 5
>   bytes.  For all encodings of more than one byte, the initial byte
>   determines the number of bytes used and the high-order bit in each byte
>   is set.
>
>   An easy way to remember this transformation format is to note that the
>   number of high-order 1's in the first byte is the same as the number of
>   subsequent bytes in the multibyte character:
>
>      Bits  Hex Min  Hex Max         Byte Sequence in Binary
>   1    7  00000000 0000007f 0zzzzzzz
>   2   13  00000080 0000207f 10zzzzzz 1yyyyyyy
>   3   19  00002080 0008207f 110zzzzz 1yyyyyyy 1xxxxxxx
>   4   25  00082080 0208207f 1110zzzz 1yyyyyyy 1xxxxxxx 1wwwwwww
>   5   31  02082080 7fffffff 11110zzz 1yyyyyyy 1xxxxxxx 1wwwwwww 1vvvvvvv
This encoding scheme is wrong; where did you get it from? Maybe it's the 
obsolete UTF-8...

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