libstdc++: Fix std::format for pointers [PR110239]

The formatter for pointers was casting to uint64_t which sign extends a
32-bit pointer and produces a value that won't fit in the provided
buffer. Cast to uintptr_t instead.

There was also a bug in the __parse_integer helper when converting a
wide string to a narrow string in order to use std::from_chars on it.
The function would always try to read 32 characters, even if the format
string was shorter than that. Fix that bug, and remove the constexpr
implementation of __parse_integer by just using __from_chars_alnum
instead of from_chars, because that's usable in constexpr even in
C++20.

libstdc++-v3/ChangeLog:

	PR libstdc++/110239
	* include/std/format (__format::__parse_integer): Fix buffer
	overflow for wide chars.
	(formatter<const void*, C>::format): Cast to uintptr_t instead
	of uint64_t.
	* testsuite/std/format/string.cc: Test too-large widths.

0 files changed, 0 insertions, 0 deletions