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[u8] -> H256

let input: [u8];
let tx_hash = H256::from_slice(&input[0..32]);

[u8; n] -> [u8; 4]

let mut buf = [0u8; 4];
buf.copy_from_slice(&input[32..36]);

[0u8; 4] -> u32

let buf = [0u8; 4];
index = u32::from_le_bytes(buf);

u32 -> [0u8; 4]

let input: u32;
input.to_le_bytes()

[u8; 32] 拼接到 Vec

let input1: [u8; 32];
let input2: [u8; 32];
let mut ret = Vec::with_capacity(64);
ret.extend_from_slice(&input);
ret.extend_from_slice(&input1);

&str -> H256

 H256(h256!("0xe778611f59d65bc0c558a0a14a7fe12c4a937712f9cae6ca7aa952802703bd5a").0)

&str -> [u8; 32]

h256!("0xe778611f59d65bc0c558a0a14a7fe12c4a937712f9cae6ca7aa952802703bd5a").0

pub fn decode_hex(s: &str) -> [u8; 32] {
    let mut buf = [0u8; 32];
    hex::decode_to_slice(s, &mut buf).unwrap();
    buf
}

对字符串签名

pub static ref ALWAYS_SUCCESS_DEPLOY_TX_HASH: [u8; 32] = Hasher::digest("AlwaysSuccessDeployTx").0;