Add Hardware Abstraction Layer (#56)

backend/src/hal/api/mat_znx.rs

@@ -0,0 +1,17 @@
+use crate::hal::layouts::MatZnxOwned;
+
+/// Allocates as [crate::hal::layouts::MatZnx].
+pub trait MatZnxAlloc {
+    fn mat_znx_alloc(&self, rows: usize, cols_in: usize, cols_out: usize, size: usize) -> MatZnxOwned;
+}
+
+/// Returns the size in bytes to allocate a [crate::hal::layouts::MatZnx].
+pub trait MatZnxAllocBytes {
+    fn mat_znx_alloc_bytes(&self, rows: usize, cols_in: usize, cols_out: usize, size: usize) -> usize;
+}
+
+/// Consume a vector of bytes into a [crate::hal::layouts::MatZnx].
+/// User must ensure that bytes is memory aligned and that it length is equal to [MatZnxAllocBytes].
+pub trait MatZnxFromBytes {
+    fn mat_znx_from_bytes(&self, rows: usize, cols_in: usize, cols_out: usize, size: usize, bytes: Vec<u8>) -> MatZnxOwned;
+}