[libcxx-commits] [PATCH] D114395: [libc++] Fix the return value of max_size()

[Marshall Clow via Phabricator via libcxx-commits]

mclow.lists added a comment.

The definition of `max_size()` is the maximum number of elements that a `string_view` can hold.  
(Actual definition: Returns: The largest possible number of char-like objects that can be referred to by a `basic_string_view`.)

Also, `numeric_limits<size_t>::max()` is the maximum size (in bytes) of any data structure.

My argument is that those two imply that `sv.max_size() * sizeof(sv::value_type)` (pardon the fak-ey code) should:

- Not overflow.
- Be no larger than `numeric_limits<size_t>::max()`

Interestingly enough:

- libstdc++ returns: `(numeric_limits<size_t>::max() - epsilon)/sizeof(Elem)`
- MSVC returns:      `min(numeric_limits<ptrdiff_t>::max(), numeric_limits<size_t>::max() - eps)/sizeof(Elem))`


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D114395/new/

https://reviews.llvm.org/D114395