PoolAllocator

This class contains the extracted G3D memory allocator which can be used with SIMDString class. The code doesn't have any additional dependencies, differently than the g3d_allocator, which pulls in practically the entire G3D-base library's code (sic!!!).

Note: the extracted allocator seems to be implemeneted as a pooled block allocator (a small block free list allocator).

Usage:

#define NO_G3D_ALLOCATOR 1 
#include <SIMDString.h>

#include <PoolAllocator.h>

using SIMDString = SIMDString<64, G3D::g3d_pool_allocator<char>>;

SIMDString strg("0123456789abcdefghijklmnopqrstuvwxyz");

This code can be seen in action in the SimdStringTest.cpp source file

TODO:

• support for older VisualStudio compilers dropped in 'mallocStatus()' as for now -> add it?
• add CMake support, test on Linux
• package the allocator as a std::memory_resource (??)
• compare performance of SIMDString with the G3D allocator vs. std::pool_memory_resource
• switch to using SIMDString as an external github module (???)

OPEN:

• SIMDString (which is also extracted from G3D codebase) has a MIT-license, but G3D allocator's files have BSD license. Anybody knows what licence the SIMDString + PoolAllocator combo would have???

About SIMDString optimizations: (from a 2022 CppCon presentation)

"From what we’ve seen so far, here are the properties of string usage in graphics. These tell us the requirements our string class should have.

Of these, the most important to note are that many strings are small or empty, and many reside in the const segment of the compiled executable.

So, from these we need optimized: copy construction, concatenation, conversion from 'const char*'

And, of course, we can’t have a class with just these operations---we need the behavior of the full std::string and we need it to be as performant as possible. It needs to fit the standard string ecosystem. Many game engines use standard string. We want a drop-in replacement for standard string that implements the full 'std::string' API and is performant for large strings and optimized for shorter strings."