Mailing lists / fpc-devel / 2006-10
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Hello,
If I have a ansistring, and cast that to a WideString, fpc is converting from which encoding to which encoding?
ansistring can hold utf-8 also, not only iso. I'm not sure what WideString holds. Maybe UTF-16? Or a limited UTF-16 with only 2 bytes characters.
thanks,
Op Tue, 10 Oct 2006, schreef Felipe Monteiro de Carvalho:
Hello, If I have a ansistring, and cast that to a WideString, fpc is converting from which encoding to which encoding?
Without widestring manager, it converts iso-8859-1 to UCS-2.
ansistring can hold utf-8 also, not only iso.
Yes, but in that case, declare it as UTF8string. There exist functions UTF8encode and UTF8decode to convert between an UTF8string and a widestring.
I'm not sure what WideString holds. Maybe UTF-16? Or a limited UTF-16 with only 2 bytes characters.
UCS-2. Basically this is UTF-16 with only 2-byte characters, allthough there are small differences in the high regions; UCS-2 is code points $0..$ffff, while UTF-16 has facilities to allow for multiword characters.
Daniël
there is nothing intrinsic about how widestring is implemented that stops it holding UTF-16 multiword characters, its just a matter of whether the routines its passed to do (on windows i belive surrogate support depends on a registry setting and is disabled by default on western editions).
If I have a ansistring, and cast that to a WideString, fpc is converting from which…
If I have a ansistring, and cast that to a WideString, fpc is converting from which encoding to which encoding?
the default is ISO-8859-1 to UCS-2/UTF-16 (the only difference between the two being UTF-16 support for surrogates), however this can be changed by registering a widestring manager.
personally if you wan't good internationalisation support i would advise avoiding the implicit conversion between ansistrings and widestrings and thinking through exactly what conversion you wan't in a particular situation, after all as you say an ansistring can hold anything.
for example if writing a html interperter you would base your conversion on the charset part of the content type.
Would the devs consider adding a compile option to disable implicit conversions between ansistrings and widestrings (as i belive in applications working with multiple encodings accidental use of them could be a major source of bigs)?