Re: [Openexr-devel] UNICODE support in openexr file I/O

[Florian Kainz]

OpenEXR uses strings in three places:

- File names
- Attribute names, for example, "displayWindow" or "pixelAspectRatio".
- Attribute values, for example the channel names in the channels attribute.

String processing operations performed by the IlmImf library include:

- copying
- comparing and sorting, in order to find attributes or channels by name
- concatenation, usually to generate error messages such as
  "Cannot open file foo.exr (Permission denied)."

As far as I know, all of those operations work the same way for regular char 
strings and for UTF-8-encoded Unicode.  (Character counting or sub-string 
extraction would have to know about UTF-8, but we don't do that in IlmImf.)

Florian


Bob Friesenhahn wrote:
> On Thu, 19 Jan 2006, Yves Poissant wrote:
>
> > Re: [Openexr-devel] UNICODE support in openexr file I/OYou don't need 
> > any changes in the interface to support UTF-8. Storing and retrieving 
> > UTF-8 strings is done with traditional 8bits string based functions. 
> > IMO, something like "character strings are in UTF-8 format" could be 
> > part of the specifications though. Unless you are thinking about sone 
> > API that would translate UTF-8 to Unicode back and forth automatically.
>
> My understanding of UTF-8 is that some characters require multiple 
> octets to represent so it is not so simple as simply assuming that 
> strings are UTF-8.  The library needs to be prepared to handle UTF-8 
> internally if it does any string parsing.  It needs to know for sure if 
> the string is UTF-8.  Some existing strings may use extended characters 
> (in the system's native character set) but not UTF-8.
>
> Bob
> ======================================
> Bob Friesenhahn
> address@hidden, http://www.simplesystems.org/users/bfriesen/
> GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
>
>
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