[libcxx] r213785 - Fix ctype_base::xdigit for Android.

[Dan Albert]

As of right now, the only callers for the android platform flavor of this
function are the tests (otherwise I would have heard of the breakage
sooner).

I think I was unclear earlier. Every other implementation I've looked at
considers _CTYPE_X to match [0-9a-f], it is only OpenBSD (and by extension,
Android) that do the non obvious thing of only matching [a-f]. All this
does is make us match the rest of the world.


On Wed, Jul 23, 2014 at 5:02 PM, Nico Weber <thakis at chromium.org> wrote:

> On Wed, Jul 23, 2014 at 12:51 PM, Dan Albert <danalbert at google.com> wrote:
>
>> Without this patch only a-f get matched as hex digits, and 0-9 do not.
>> IMO this is a deficiency in the C library, but for backward compatibility
>> reasons we can't change our ctype implementation.
>>
>
> Is this function used heavily? Since it seems to be broken, apps probably
> can't rely on it – and the ones that do probably don't know that the
> function is broken and would work better if this changed. Do you have data
> on how many apps call this function?
>
>
>>
>> One other idea I had toyed with was just adding a less broken ctable
>> implementation (probably netbsd's) to bionic for use with libc++ (and
>> perhaps the LP64 ABIs?) while still leaving the openbsd one around for
>> compatibility, but I don't think having two ctype implementations in bionic
>> is a very good solution either.
>>
>> - Dan
>>
>>
>> On Wed, Jul 23, 2014 at 12:45 PM, Nico Weber <thakis at chromium.org> wrote:
>>
>>> On Wed, Jul 23, 2014 at 12:32 PM, Dan Albert <danalbert at google.com>
>>> wrote:
>>>
>>>> Author: danalbert
>>>> Date: Wed Jul 23 14:32:03 2014
>>>> New Revision: 213785
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=213785&view=rev
>>>> Log:
>>>> Fix ctype_base::xdigit for Android.
>>>>
>>>> Android's ctype implementation comes from openbsd, which for some reason
>>>> doesn't consider numbers to be hex digits.
>>>>
>>>
>>> That seems broken. What happens without this patch? libc++ and C library
>>> don't agree on what hex digits are?
>>>
>>>
>>>>
>>>> Modified:
>>>>     libcxx/trunk/include/__locale
>>>>
>>>> Modified: libcxx/trunk/include/__locale
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/__locale?rev=213785&r1=213784&r2=213785&view=diff
>>>>
>>>> ==============================================================================
>>>> --- libcxx/trunk/include/__locale (original)
>>>> +++ libcxx/trunk/include/__locale Wed Jul 23 14:32:03 2014
>>>> @@ -366,7 +366,12 @@ public:
>>>>      static const mask alpha  = _CTYPE_A;
>>>>      static const mask digit  = _CTYPE_D;
>>>>      static const mask punct  = _CTYPE_P;
>>>> +# if defined(__ANDROID__)
>>>> +    static const mask xdigit = _CTYPE_X | _CTYPE_D;
>>>> +# else
>>>>      static const mask xdigit = _CTYPE_X;
>>>> +# endif
>>>> +
>>>>  # if defined(__NetBSD__)
>>>>      static const mask blank  = _CTYPE_BL;
>>>>  # else
>>>>
>>>>
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>>>>
>>>
>>>
>>
>
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