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Is it OK to include an ANSI file into a UTF-8 file?

P: n/a
aa
Is it OK to include an ANSI file into a UTF-8 file?
Jul 17 '05 #1
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P: n/a
aa <aa@virgin.net> wrote:
Is it OK to include an ANSI file into a UTF-8 file?


What is an ANSI file?

But the answer is obviuos, as long as the ANSI file is to the utf8
conventions the inclusion results in valid utf8.

So is it valid utf8? man utf-8:
<q>
PROPERTIES
The UTF-8 encoding has the following nice properties:

* UCS characters 0x00000000 to 0x0000007f (the classic US-ASCII charac-
ters) are encoded simply as bytes 0x00 to 0x7f (ASCII compatibility).
This means that files and strings which contain only 7-bit ASCII
characters have the same encoding under both ASCII and UTF-8.

* All UCS characters > 0x7f are encoded as a multi-byte sequence con-
sisting only of bytes in the range 0x80 to 0xfd, so no ASCII byte can
appear as part of another character and there are no problems with
e.g. '\0' or '/'.
[...]
* The bytes 0xfe and 0xff are never used in the UTF-8 encoding.

* The first byte of a multi-byte sequence which represents a single
non-ASCII UCS character is always in the range 0xc0 to 0xfd and indi-
cates how long this multi-byte sequence is. All further bytes in a
multi-byte sequence are in the range 0x80 to 0xbf. This allows easy
resynchronization and makes the encoding stateless and robust against
missing bytes.
[...]

ENCODING
The following byte sequences are used to represent a character. The
sequence to be used depends on the UCS code number of the character:

0x00000000 - 0x0000007F:
0xxxxxxx

0x00000080 - 0x000007FF:
110xxxxx 10xxxxxx

0x00000800 - 0x0000FFFF:
1110xxxx 10xxxxxx 10xxxxxx

0x00010000 - 0x001FFFFF:
11110xxx 10xxxxxx 10xxxxxx 10xxxxxx

0x00200000 - 0x03FFFFFF:
111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx

0x04000000 - 0x7FFFFFFF:
1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx

The xxx bit positions are filled with the bits of the character code
number in binary representation. Only the shortest possible multi-byte
sequence which can represent the code number of the character can be
used.

The UCS code values 0xd800-0xdfff (UTF-16 surrogates) as well as 0xfffe
and 0xffff (UCS non-characters) should not appear in conforming UTF-8
streams.
</q>

But why simply include so it might go wrong (now or in the future), when
you can use the mbstring/iconv functions to correctly convert whatever
is in the the include file to valid utf-8!

--

Daniel Tryba

Jul 17 '05 #2

P: n/a
aa
Thanks, Daniel, for the most comprehensive answer.
Just to check if I understand you correctly:
As ASCII characters have the same encoding under both ASCII and UTF-8 and
no ASCII byte can
appear as part of another character of UTF-8, then an ASCII included
into a UTF-8 file will be interpreted correctly.

Regarding ANSI - this is not my field and if I am wrong, please correct me.
I believe that ANSI it is 8 bit code i.e. 256 combinatons
The first 128 ( bytes 0x00 to 0x7f ) are ASCII. The remaining 128 bytes
(0x80 to 0xff ) can be interpreted as anything depending on the code table
applied. The code table applied depends on the OS system code page. If, for
example it is set to 850 then these are Western European characters like
French apostrophe or German double dot over letters etc.
If the system code page is set to 866, the last half is interpreted as
Cyrillics.
Also the system code page interpretation can be overruled by setting of
charset attribute in an HTML file or by encoding settings in the browser.

If my guesses above are correct, then what will happen to an ANSI file if
it is included into a UTF-8 file?
Using your terminology, how bytes 0x80 to 0xff will be interpreted?

"Daniel Tryba" <ne****************@canopus.nl> wrote in message
news:ck**********@news.tue.nl...
aa <aa@virgin.net> wrote:
Is it OK to include an ANSI file into a UTF-8 file?
What is an ANSI file?

But the answer is obviuos, as long as the ANSI file is to the utf8
conventions the inclusion results in valid utf8.

So is it valid utf8? man utf-8:
<q>
PROPERTIES
The UTF-8 encoding has the following nice properties:

* UCS characters 0x00000000 to 0x0000007f (the classic US-ASCII

charac- ters) are encoded simply as bytes 0x00 to 0x7f (ASCII compatibility). This means that files and strings which contain only 7-bit ASCII characters have the same encoding under both ASCII and UTF-8.

* All UCS characters > 0x7f are encoded as a multi-byte sequence con- sisting only of bytes in the range 0x80 to 0xfd, so no ASCII byte can appear as part of another character and there are no problems with e.g. '\0' or '/'.
[...]
* The bytes 0xfe and 0xff are never used in the UTF-8 encoding.

* The first byte of a multi-byte sequence which represents a single non-ASCII UCS character is always in the range 0xc0 to 0xfd and indi- cates how long this multi-byte sequence is. All further bytes in a multi-byte sequence are in the range 0x80 to 0xbf. This allows easy resynchronization and makes the encoding stateless and robust against missing bytes.
[...]

ENCODING
The following byte sequences are used to represent a character. The sequence to be used depends on the UCS code number of the character:
0x00000000 - 0x0000007F:
0xxxxxxx

0x00000080 - 0x000007FF:
110xxxxx 10xxxxxx

0x00000800 - 0x0000FFFF:
1110xxxx 10xxxxxx 10xxxxxx

0x00010000 - 0x001FFFFF:
11110xxx 10xxxxxx 10xxxxxx 10xxxxxx

0x00200000 - 0x03FFFFFF:
111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx

0x04000000 - 0x7FFFFFFF:
1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx

The xxx bit positions are filled with the bits of the character code number in binary representation. Only the shortest possible multi-byte sequence which can represent the code number of the character can be used.

The UCS code values 0xd800-0xdfff (UTF-16 surrogates) as well as 0xfffe and 0xffff (UCS non-characters) should not appear in conforming UTF-8 streams.
</q>

But why simply include so it might go wrong (now or in the future), when
you can use the mbstring/iconv functions to correctly convert whatever
is in the the include file to valid utf-8!

--

Daniel Tryba

Jul 17 '05 #3

P: n/a
aa <aa@virgin.net> wrote:
If my guesses above are correct, then what will happen to an ANSI file if
it is included into a UTF-8 file?
Using your terminology, how bytes 0x80 to 0xff will be interpreted?


That is undefined, it might result in a legal utf8 sequence, propably
will not.

I guess it could result in parse errrors in php code.

If this should happen in a string the was send to the browsers, the
illegal sequence will probably be displayed as an '?' or the unicode
char for an illegal char: http://www.unicode.org/charts/img/UFFFD.gif

[snipping 97 useless lines]

--

Daniel Tryba

Jul 17 '05 #4

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