memory-cache-rust 0.1.0-alpha

memory-cache is a fast, concurrent cache library built with a focus on performance and correctness. The motivation to build Ristretto comes from the need for a contention-free cache in
Documentation 
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use std::hash::{Hash, Hasher};

pub type NanoTime = Box<dyn Fn(i64) -> i64>;
pub type CPUTicks = Box<dyn Fn(i64) -> i64>;
pub type Memhash = Box<dyn Fn(*const str, *const usize, *const usize) -> u64>;

unsafe fn any_as_u8_slice<T: Sized>(p: &T) -> &[u8] {
    ::std::slice::from_raw_parts(
        (p as *const T) as *const u8,
        ::std::mem::size_of::<T>(),
    )
}


#[repr(C)]
pub struct StringStruct([u8; 32]);

impl Hash for StringStruct {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.0.hash(state)
    }
}

/// mem_hash is the hash function used by go map, it utilizes available hardware instructions(behaves
/// as aeshash if aes instruction is available).
/// NOTE: The hash seed changes for every process. So, this cannot be used as a persistent hash.
pub fn mem_hash(data: &[u8]) -> u64 {
    // let (head, body, _tail) = unsafe { data.align_to::<StringStruct>() };
    // assert!(head.is_empty(), "Data was not aligned");
    // let my_struct = &body[0];

    let hash = seahash::hash(data);
    // let my_struct =   unsafe { data.as_mut_ptr() as *mut StringStruct };
    // let mut s = DefaultHasher::new();
    // my_struct.hash(&mut s);
    // let hash = s.finish();
    hash
}

/// mem_hash is the hash function used by go map, it utilizes available hardware instructions(behaves
/// as aeshash if aes instruction is available).
/// NOTE: The hash seed changes for every process. So, this cannot be used as a persistent hash.
pub fn mem_hash_byte(data: &[u8]) -> u64 {
    // let (head, body, _tail) = unsafe { data.align_to::<StringStruct>() };
    // assert!(head.is_empty(), "Data was not aligned");
    // let my_struct = &body[0];

    let hash = seahash::hash(data);
    // let my_struct =   unsafe { data.as_mut_ptr() as *mut StringStruct };
    // let mut s = DefaultHasher::new();
    // my_struct.hash(&mut s);
    // let hash = s.finish();
    hash
}