alchemy/src/transmutable.rs

use std::{u8, u16, u32, u64, usize};
use std::{i8, i16, i32, i64, isize};

use ::converter::Converter;
use ::endian::{BigEndian, LittleEndian, PlatformEndian, Endianess};



/// Handles the repetative 
macro_rules! handle_endianess_to_bytes
{
   ($buffer: ident, $val: ident, $endianess: ident, $func: ident) =>
   {
      {
         let mut mut_buffer;

         mut_buffer = $buffer;
         match $endianess
         {
            Endianess::BIG =>
            {
               BigEndian::$func(&mut mut_buffer, *$val);
            }

            Endianess::LITTLE =>
            {
               LittleEndian::$func(&mut mut_buffer, *$val);
            }

            Endianess::PLATFORM =>
            {
               PlatformEndian::$func(&mut mut_buffer, *$val);
            }
         }
      }
   }
}

macro_rules! handle_endianess_from_bytes
{
   ($buffer: ident, $endianess: ident, $func: ident) =>
   {
      match $endianess
      {
         Endianess::BIG =>
         {
            BigEndian::$func(&$buffer)
         }

         Endianess::LITTLE =>
         {
            LittleEndian::$func(&$buffer)
         }

         Endianess::PLATFORM =>
         {
            PlatformEndian::$func(&$buffer)
         }
      }
   }
}



// From and Into are not used because we need to also
// know the endianess to use for converting.
/// A type that can be converted to and from bytes.
pub trait Transmutable
{
   /// Transmute this type to an array of bytes.
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess);

   /// Transmute an array of bytes to this type.
   fn from_bytes(buffer: &[u8], endianess: Endianess) -> Self;
}



impl Transmutable for u8
{
   #[allow(unused_variables)]
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= u8::BYTES);

      // Convert this to bytes and add it to the buffer.
      // Endianess doesn't matter here.
      buffer[0] = *self;
   }

   #[allow(unused_variables)]
   fn from_bytes(buffer: &[u8], endianess: Endianess) -> u8
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= u8::BYTES);

      // Convert the given bytes to this type and return it.
      // Endianess doesn't matter here.
      buffer[0]
   }
}

impl Transmutable for u16
{
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= u16::BYTES);

      // Convert this to bytes and add it to the buffer.
      handle_endianess_to_bytes!(buffer, self, endianess, u16_to_bytes);
   }

   fn from_bytes(buffer: &[u8], endianess: Endianess) -> u16
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= u16::BYTES);

      // Convert the given bytes to this type and return is.
      handle_endianess_from_bytes!(buffer, endianess, bytes_to_u16)
   }
}

impl Transmutable for u32
{
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= u32::BYTES);

      // Convert this to bytes and add it to the buffer.
      handle_endianess_to_bytes!(buffer, self, endianess, u32_to_bytes);
   }

   fn from_bytes(buffer: &[u8], endianess: Endianess) -> u32
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= u32::BYTES);

      // Convert the given bytes to this type and return is.
      handle_endianess_from_bytes!(buffer, endianess, bytes_to_u32)
   }
}

impl Transmutable for u64
{
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= u64::BYTES);

      // Convert this to bytes and add it to the buffer.
      handle_endianess_to_bytes!(buffer, self, endianess, u64_to_bytes);
   }

   fn from_bytes(buffer: &[u8], endianess: Endianess) -> u64
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= u64::BYTES);

      // Convert the given bytes to this type and return is.
      handle_endianess_from_bytes!(buffer, endianess, bytes_to_u64)
   }
}

impl Transmutable for usize
{
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= usize::BYTES);

      // Convert this to bytes and add it to the buffer.
      handle_endianess_to_bytes!(buffer, self, endianess, usize_to_bytes);
   }

   fn from_bytes(buffer: &[u8], endianess: Endianess) -> usize
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= usize::BYTES);

      // Convert the given bytes to this type and return is.
      handle_endianess_from_bytes!(buffer, endianess, bytes_to_usize)
   }
}

impl Transmutable for i8
{
   #[allow(unused_variables)]
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= i8::BYTES);

      // Convert this to bytes and add it to the buffer.
      buffer[0] = *self as u8;
   }

   #[allow(unused_variables)]
   fn from_bytes(buffer: &[u8], endianess: Endianess) -> i8
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= i8::BYTES);

      // Convert the given bytes to this type and return it.
      // Endianess doesn't matter here.
      buffer[0] as i8
   }
}

impl Transmutable for i16
{
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= i16::BYTES);

      // Convert this to bytes and add it to the buffer.
      handle_endianess_to_bytes!(buffer, self, endianess, i16_to_bytes);
   }

   fn from_bytes(buffer: &[u8], endianess: Endianess) -> i16
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= i16::BYTES);

      // Convert the given bytes to this type and return is.
      handle_endianess_from_bytes!(buffer, endianess, bytes_to_i16)
   }
}

impl Transmutable for i32
{
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= i32::BYTES);

      // Convert this to bytes and add it to the buffer.
      handle_endianess_to_bytes!(buffer, self, endianess, i32_to_bytes);
   }

   fn from_bytes(buffer: &[u8], endianess: Endianess) -> i32
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= i32::BYTES);

      // Convert the given bytes to this type and return is.
      handle_endianess_from_bytes!(buffer, endianess, bytes_to_i32)
   }
}

impl Transmutable for i64
{
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= i64::BYTES);

      // Convert this to bytes and add it to the buffer.
      handle_endianess_to_bytes!(buffer, self, endianess, i64_to_bytes);
   }

   fn from_bytes(buffer: &[u8], endianess: Endianess) -> i64
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= i64::BYTES);

      // Convert the given bytes to this type and return is.
      handle_endianess_from_bytes!(buffer, endianess, bytes_to_i64)
   }
}

impl Transmutable for isize
{
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= isize::BYTES);

      // Convert this to bytes and add it to the buffer.
      handle_endianess_to_bytes!(buffer, self, endianess, isize_to_bytes);
   }

   fn from_bytes(buffer: &[u8], endianess: Endianess) -> isize
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= isize::BYTES);

      // Convert the given bytes to this type and return is.
      handle_endianess_from_bytes!(buffer, endianess, bytes_to_isize)
   }
}

impl Transmutable for f32
{
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= 4);

      // Convert this to bytes and add it to the buffer.
      handle_endianess_to_bytes!(buffer, self, endianess, f32_to_bytes);
   }

   fn from_bytes(buffer: &[u8], endianess: Endianess) -> f32
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= 4);

      // Convert the given bytes to this type and return is.
      handle_endianess_from_bytes!(buffer, endianess, bytes_to_f32)
   }
}

impl Transmutable for f64
{
   fn to_bytes(&self, buffer: &mut [u8], endianess: Endianess)
   {
      // Make sure that there is enough space to store
      // the bytes from this type.
      assert!(buffer.len() >= 8);

      // Convert this to bytes and add it to the buffer.
      handle_endianess_to_bytes!(buffer, self, endianess, f64_to_bytes);
   }

   fn from_bytes(buffer: &[u8], endianess: Endianess) -> f64
   {
      // Make sure that there is enough data to read
      // the bytes for this type.
      assert!(buffer.len() >= 8);

      // Convert the given bytes to this type and return is.
      handle_endianess_from_bytes!(buffer, endianess, bytes_to_f64)
   }
}