Bits256

In Fuel, a type called b256 represents hashes and holds a 256-bit value. The Rust SDK represents b256 as Bits256(value) where value is a [u8; 32]. If your contract method takes a b256 as input, you must pass a Bits256([u8; 32]) when calling it from the SDK.

Here's an example:

        let b256 = Bits256([1; 32]);

        let call_handler = contract_instance.methods().b256_as_input(b256);

If you have a hexadecimal value as a string and wish to convert it to Bits256, you may do so with from_hex_str:

        let hex_str = "0101010101010101010101010101010101010101010101010101010101010101";

        let bits256 = Bits256::from_hex_str(hex_str)?;

        assert_eq!(bits256.0, [1u8; 32]);

        // With the `0x0` prefix
        let hex_str = "0x0101010101010101010101010101010101010101010101010101010101010101";

        let bits256 = Bits256::from_hex_str(hex_str)?;

        assert_eq!(bits256.0, [1u8; 32]);