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Subject: Re: [boost] RFC: interest in Unicode codecs?
From: Eric Niebler (eric_at_[hidden])
Date: 2009-07-20 13:42:41

Mathias Gaunard wrote:
> Rogier van Dalen wrote:
>> Non-checking iterator adaptors can be faster. That would be useful
>> when you know that a string is safe, for example, in a UTF string type
>> that has a validity invariant.
> I suppose that type of string should probably use optimized iterators
> that make use of the fact it is stored on contiguous and properly
> aligned memory anyway, so it will need special code.

There are 2 orthogonal issues here:
1) whether a sequence is stored in contiguous memory
2) whether it is already guaranteed to be well-formed UTF-XX

Conflating the two will lead to bad design. I agree with Rogier. The
routines should make checking a policy. Iterators should be non-checked.
Checked iterators can be adaptors.

This is important to get right. You can build safe interfaces on top of
fast ones, but not the other way around.

Eric Niebler
BoostPro Computing

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