gistfile1.txt

pub enum Alphabet {
	All,
	Low,
	Mid,
	Custom(Bytes),
}

pub struct StandardMap {
	alphabet: Alphabet,
	min_key: usize,
	journal_key: usize,
	count: usize,
}

impl StandardMap {
	fn random_bytes(min_count: usize, journal_count: usize, seed: &mut H256) -> Vec<u8> {
		assert!(min_count + journal_count <= 32);
		*seed = seed.sha3();
		let r = min_count + (seed.bytes()[31] as usize % (journal_count + 1));
		seed.bytes()[0..r].to_vec()
	}

	fn random_value(seed: &mut H256) -> Bytes {
		*seed = seed.sha3();
		match seed.bytes()[0] % 2 {
			1 => vec![seed.bytes()[31];1],
			_ => seed.bytes().to_vec(),
		}
	}

	fn random_word(alphabet: &[u8], min_count: usize, journal_count: usize, seed: &mut H256) -> Vec<u8> {
		assert!(min_count + journal_count <= 32);
		*seed = seed.sha3();
		let r = min_count + (seed.bytes()[31] as usize % (journal_count + 1));
		let mut ret: Vec<u8> = Vec::with_capacity(r);
		for i in 0..r {
			ret.push(alphabet[seed.bytes()[i] as usize % alphabet.len()]);
		}
		ret
	}

	pub fn make(&self) -> Vec<(Bytes, Bytes)> {
		let low = b"abcdef";
		let mid = b"@QWERTYUIOPASDFGHJKLZXCVBNM[/]^_";

		let mut d: Vec<(Bytes, Bytes)> = Vec::new();
		let mut seed = H256::new();
		for _ in 0..self.count {
			let k = match self.alphabet {
				Alphabet::All => Self::random_bytes(self.min_key, self.journal_key, &mut seed),
				Alphabet::Low => Self::random_word(low, self.min_key, self.journal_key, &mut seed),
				Alphabet::Mid => Self::random_word(mid, self.min_key, self.journal_key, &mut seed),
				Alphabet::Custom(ref a) => Self::random_word(&a, self.min_key, self.journal_key, &mut seed),
			};
			let v = Self::random_value(&mut seed);
			d.push((k, v))
		}
		d
	}
}