ps-alloc - a reasonably safe allocator

This crate provides three functions: alloc, free, and realloc. They are thin wrappers over the system allocator with best-effort runtime misuse detection.

Every allocation is prefixed with a hidden 16-byte header storing a marker and the allocation's size, and every returned pointer is aligned to 16 bytes.

While this crate does implement several safety precautions, you still shouldn't call free on stuff willy-nilly, because that is undefined behaviour.

free is NOT guaranteed to fail when provided anything other than a valid pointer produced by alloc or realloc.

Do not call free on any pointer not produced by alloc or realloc.

Unlike C's free(NULL), freeing a null pointer returns an error instead of being a no-op.

realloc mirrors C's realloc: realloc(null, size) allocates, realloc(ptr, 0) frees and returns null, and resizing preserves the contents up to the lesser of the old and new sizes, in place when possible. After a successful realloc, only the returned pointer may be used.

All three functions return Results. alloc returning an Err does not signify a problem. free or realloc returning any error besides NullPtr, or realloc's recoverable NewAllocationFailed, means your program is already in an undefined state and you should consider aborting it.