meli/melib/src/email/compose/random.rs

81 lines
2.1 KiB
Rust

/*
* meli - melib crate.
*
* Copyright 2017-2020 Manos Pitsidianakis
*
* This file is part of meli.
*
* meli is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* meli is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with meli. If not, see <http://www.gnu.org/licenses/>.
*/
use std::char;
use std::fs::File;
use std::io::prelude::*;
use std::time::SystemTime;
pub fn random_u64() -> u64 {
let mut f = File::open("/dev/urandom").unwrap();
let mut buffer = [0; 8];
// read exactly 10 bytes
f.read_exact(&mut buffer).unwrap();
u64::from(buffer[0])
| (u64::from(buffer[1]) << 8)
| (u64::from(buffer[2]) << 16)
| (u64::from(buffer[3]) << 24)
| (u64::from(buffer[4]) << 32)
| (u64::from(buffer[5]) << 40)
| (u64::from(buffer[6]) << 48)
| (u64::from(buffer[7]) << 56)
}
fn clock() -> u64 {
SystemTime::now()
.duration_since(SystemTime::UNIX_EPOCH)
.unwrap()
.as_secs()
}
fn base36(mut m: u64) -> String {
let mut stack = Vec::with_capacity(32);
while m >= 36 {
stack.push((m % 36) as u32);
m /= 36;
}
let mut ret = String::with_capacity(stack.len());
while let Some(d) = stack.pop() {
ret.push(char::from_digit(d, 36).unwrap());
}
ret
}
pub fn gen_message_id(fqdn: &str) -> String {
let clock = base36(clock());
let rand = base36(random_u64());
format!("<{}.{}@{}>", clock, rand, fqdn)
}
pub fn gen_boundary() -> String {
let clock = base36(clock());
let rand = base36(random_u64());
let rand2 = base36(random_u64());
format!("{}{}{}", rand, clock, rand2)
}