u8.rs

use support::{decl_module, decl_storage, decl_event, StorageValue, dispatch::Result};
use system::ensure_signed;

pub trait Trait: system::Trait {
	type Event: From<Event<Self>> + Into<<Self as system::Trait>::Event>;
}

type U8 = [u8; 1];

decl_storage! {
	trait Store for Module<T: Trait> as TemplateModule {
		MyByte get(my_byte): U8;
	}
}

decl_module! {
	pub struct Module<T: Trait> for enum Call where origin: T::Origin {

		fn deposit_event<T>() = default;

		pub fn set_my_byte(origin, input: U8) -> Result {
			let who = ensure_signed(origin)?;

			<MyByte<T>>::put(input);

			Self::deposit_event(RawEvent::MyByteStored(input, who));
			Ok(())
		}

		pub fn add_to_byte(origin, input: U8) -> Result {
			let who = ensure_signed(origin)?;

			let my_byte = Self::my_byte()[0];
			let my_new_byte = my_byte.checked_add(input[0]).ok_or("Overflow")?;

			<MyByte<T>>::put([my_new_byte]);
			Self::deposit_event(RawEvent::MyByteStored([my_new_byte], who));
			Ok(())
		}
	}
}

decl_event!(
	pub enum Event<T> where AccountId = <T as system::Trait>::AccountId {
		MyByteStored(U8, AccountId),
	}
);