asbytes 0.3.0

Traits for viewing data as byte slices or consuming data into byte vectors. Relies on bytemuck for POD safety.
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//! This example demonstrates the `AsBytes` trait. It shows how to get a `&[ u8]` view of various data types (a `Vec`, a slice, an array, a single struct wrapped in a tuple, and a scalar wrapped in a tuple) without consuming the original data. This is useful for operations like inspecting byte patterns, hashing data without modification, or passing byte slices to functions that only need read access. The `.byte_size()` and `.len()` methods provide convenient ways to get the size in bytes and the number of elements, respectively.

#[ cfg( not( feature = "enabled" ) ) ]
fn main() {}

#[ cfg( feature = "enabled" ) ]
fn main()
{
  // Make sure asbytes is available for derives:
  // asbytes = { version = "0.2", features = [ "derive" ] }
  use asbytes ::AsBytes;

  // Define a POD struct
  #[ repr( C ) ]
  #[ derive( Debug, Clone, Copy, asbytes ::Pod, asbytes ::Zeroable ) ]
  struct Point
  {
    x : f32,
    y : f32,
  }

  // --- Collections ---
  let points_vec : Vec< Point > = vec![ Point { x : 1.0, y : 2.0 }, Point { x : 3.0, y : 4.0 } ];
  let points_slice : &[ Point ] = &points_vec[ .. ];
  let points_array : [ Point; 1 ] = [ Point { x : 5.0, y : 6.0 } ];

  // Use AsBytes to get byte slices (&[ u8]) without consuming the original data
  let vec_bytes : &[ u8 ] = points_vec.as_bytes();
  let slice_bytes : &[ u8 ] = points_slice.as_bytes();
  let array_bytes : &[ u8 ] = points_array.as_bytes();

  println!( "Vec Bytes: length={}, data={:?}", points_vec.byte_size(), vec_bytes );
  println!( "Slice Bytes: length={}, data={:?}", slice_bytes.byte_size(), slice_bytes );
  println!( "Array Bytes: length={}, data={:?}", points_array.byte_size(), array_bytes );
  println!( "Vec Element Count: {}", points_vec.len() ); // Output: 2
  println!( "Array Element Count: {}", points_array.len() ); // Output: 1

  // --- Single POD Item (using tuple trick) ---
  let single_point = Point { x : -1.0, y : -2.0 };
  let single_point_tuple = ( single_point, ); // Wrap in a single-element tuple

  let point_bytes : &[ u8 ] = single_point_tuple.as_bytes();
  println!(
    "Single Point Bytes: length={}, data={:?}",
    single_point_tuple.byte_size(),
    point_bytes
  );
  println!( "Single Point Element Count: {}", single_point_tuple.len() ); // Output: 1

  let scalar_tuple = ( 12345u32, );
  let scalar_bytes : &[ u8 ] = scalar_tuple.as_bytes();
  println!( "Scalar Bytes: length={}, data={:?}", scalar_tuple.byte_size(), scalar_bytes );

  // Original data is still available after calling .as_bytes()
  println!( "Original Vec still usable: {points_vec:?}" );
}