[libcxx] Fix ctype_byname<wchar_t>::do_is() mask checking.

[jroelofs]

Summary

The previous method was very dependent on how the ctype masks were defined. For example, Android has print defined as (punct | upper | lower | digit | blank). When calling do_is(upper, L'a'), result would be set to true by if (upper & print) result |= iswprint_l(L'a', __l);

[danalbert]

src/locale.cpp

1208

I don't think _LIBCPP_ASSERT() is actually what I want here (since it's usually compiled out). Do we already have something akin to this for _LIBCPP_DEBUG_LEVEL < 1?

[jroelofs]

I don't think this is correct. IIRC, the value of 'm' coming in is a mask. To
fix this, all of the tests need to be of this form:

if ((m & space) == space) result |= (iswspace_l(ch, __l) != 0);

Newlib also has this problem... Sorry I didn't bring this up sooner.

Cheers,

Jon

[jroelofs]

Here's the patch I just mentioned: https://gist.github.com/jroelofs/8c6091f79ae2327f1ccb

[danalbert]

Yes, you're right. I had thought this was just one of our implementation details, but it is exposed by ctype::is().

[mclow.lists]

This is a behavior change. Today, if you pass in a mask that is not one listed, it returned false. With your change, it aborts.

That seems .. harsh.

[jroelofs]

Here's v2 of this patch: http://reviews.llvm.org/D5081

(This is a rebased version of: https://gist.github.com/jroelofs/8c6091f79ae2327f1ccb)

src/locale.cpp

 }
 
 bool
 ctype_byname<wchar_t>::do_is(mask m, char_type c) const
 {
 #ifdef _LIBCPP_WCTYPE_IS_MASK
     return static_cast<bool>(iswctype_l(c, m, __l));
 #else
-    bool result = false;
     wint_t ch = static_cast<wint_t>(c);
-    if (m & space) result |= (iswspace_l(ch, __l) != 0);
-    if (m & print) result |= (iswprint_l(ch, __l) != 0);
-    if (m & cntrl) result |= (iswcntrl_l(ch, __l) != 0);
-    if (m & upper) result |= (iswupper_l(ch, __l) != 0);
-    if (m & lower) result |= (iswlower_l(ch, __l) != 0);
-    if (m & alpha) result |= (iswalpha_l(ch, __l) != 0);
-    if (m & digit) result |= (iswdigit_l(ch, __l) != 0);
-    if (m & punct) result |= (iswpunct_l(ch, __l) != 0);
-    if (m & xdigit) result |= (iswxdigit_l(ch, __l) != 0);
-    if (m & blank) result |= (iswblank_l(ch, __l) != 0);
-    return result;
+    switch (m) {
+    case space:
+        return iswspace_l(ch, __l);
+    case print:
+        return iswprint_l(ch, __l);
+    case cntrl:
+        return iswcntrl_l(ch, __l);
+    case upper:
+        return iswupper_l(ch, __l);
+    case lower:
+        return iswlower_l(ch, __l);
+    case alpha:
+        return iswalpha_l(ch, __l);
+    case digit:
+        return iswdigit_l(ch, __l);
+    case alnum:
+        return iswalnum_l(ch, __l);
+    case punct:
+        return iswpunct_l(ch, __l);
+    case xdigit:
+        return iswxdigit_l(ch, __l);
+    case blank:
+        return iswblank_l(ch, __l);
+    case graph:
+        return iswgraph_l(ch, __l);
+    default:
+        _LIBCPP_ASSERT(false,
+                       "unhandled ctype mask in ctype_byname<wchar_t>::do_is");
+        abort();
+    }
 #endif
 }
 
 const wchar_t*
 ctype_byname<wchar_t>::do_is(const char_type* low, const char_type* high, mask* vec) const
 {
     for (; low != high; ++low, ++vec)
     {