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use std::sync::atomic::*;

/// Read [WARNING](trait.SharedMemCast.html#warning) before use
///
/// Trait used to indicate that a type can be cast over the shared memory.
///
/// For now, shared_memory implements the trait on almost all primitive types.
///
/// ### __<span style="color:red">WARNING</span>__
///
/// Only implement this trait if you understand the implications of mapping Rust types to shared memory.
/// When doing so, you should be mindful of :
/// * Does my type have any pointers in its internal representation ?
///    * This is important because pointers in your type need to also point to the shared memory for it to be usable by other processes
/// * Can my type resize its contents ?
///    * If so, the type probably cannot be safely used over shared memory because your type might call alloc/realloc/free on shared memory addresses
/// * Does my type allow for initialisation after instantiation ?
///    * A [R|W]lock to the shared memory returns a reference to your type. That means that any use of that reference assumes that the type was properly initialized.
///
/// An example of a type that __shouldnt__ be cast to the shared memory would be Vec.
/// Vec internaly contains a pointer to a slice containing its data and some other metadata.
/// This means that to cast a Vec to the shared memory, the memory has to already be initialized with valid pointers and metadata.
/// Granted we could initialize those fields manually, the use of the vector might then trigger a free/realloc on our shared memory.
///
pub unsafe trait SharedMemCast {}
unsafe impl SharedMemCast for bool {}
unsafe impl SharedMemCast for char {}
unsafe impl SharedMemCast for str {}
unsafe impl SharedMemCast for i8 {}
unsafe impl SharedMemCast for i16 {}
unsafe impl SharedMemCast for i32 {}
unsafe impl SharedMemCast for u8 {}
unsafe impl SharedMemCast for i64 {}
unsafe impl SharedMemCast for u16 {}
unsafe impl SharedMemCast for u64 {}
unsafe impl SharedMemCast for isize {}
unsafe impl SharedMemCast for u32 {}
unsafe impl SharedMemCast for usize {}
unsafe impl SharedMemCast for f32 {}
unsafe impl SharedMemCast for f64 {}

unsafe impl SharedMemCast for AtomicBool {}
unsafe impl SharedMemCast for AtomicIsize {}
unsafe impl<T> SharedMemCast for AtomicPtr<T> {}
unsafe impl SharedMemCast for AtomicUsize {}