On Thu, 20 Mar 2014 22:39:50 -0000, Walter Bright
<newshou...@digitalmars.com> wrote:
Currently we do it by throwing a UTFException. This has problems:
1. about anything that deals with UTF cannot be made nothrow
2. turns innocuous errors into major problems, such as DOS attack vectors
http://en.wikipedia.org/wiki/UTF-8#Invalid_byte_sequences
One option to fix this is to treat invalid sequences as:
1. the .init value (0xFF for UTF8, 0xFFFF for UTF16 and UTF32)
2. U+FFFD
I kinda like option 1.
What do you think?
In window/Win32..
WideCharToMultiByte has flags for a bunch of similar behaviours and allows
you to define a default char to use as a replacement in such cases.
swprintf when passed %S will convert a wchar_t UTF-16 argument into ascii,
and replaces invalid characters with ? as it does so.
swprintf_s (the safe version), IIRC, will invoke the invalid parameter
handler for sequences which cannot be converted.
I think, ideally, we want some sensible default behaviour but also the
ability to alter it globally, and even better in specific calls where it
makes sense to do so (where flags/arguments can be passed to that effect).
So, the default behaviour could be to throw (therefore no breaking change)
and we provide a function to change this to one of the other options, and
another to select a replacement character (which would default to .init or
U+FFFD).
R
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