[Bug libstdc++/57350] std::align missing

[potswa at mac dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57350

--- Comment #4 from David Krauss <potswa at mac dot com> ---
Hmm, I recall preparing to submit a patch but not being able to decide which
header to modify.

Here's the aforementioned MIT-licensed code. The MIT license only requires
attribution which is satisfied by the changelog; anyway I don't care. I am
already a GNU contributor with FSF waiver back in 2009.

This code should probably be reviewed. I wrote it a long time ago and seldom
used it. Cannot recall whether it was intended to be 100% compliant.


inline void *align( std::size_t alignment, std::size_t size, void *&ptr,
std::size_t &space ) {
    auto pn = reinterpret_cast< std::size_t >( ptr );
    auto aligned = ( pn + alignment - 1 ) & - alignment;
    auto new_space = space - ( aligned - pn );
    if ( new_space < size ) return nullptr;
    space = new_space;
    return ptr = reinterpret_cast< void * >( aligned );
}