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extern crate rand;
extern crate time;
extern crate rustc_serialize;
use std::mem;
use std::ptr;
use std::fmt;
use rand::{OsRng,Rng};
use rustc_serialize::base64::{self,ToBase64};
#[derive(Clone,Debug)]
pub struct TextNonce(pub String);
impl TextNonce {
pub fn new() -> TextNonce {
TextNonce::sized(32).unwrap()
}
pub fn sized(length: usize) -> Result<TextNonce,String> {
TextNonce::sized_configured(length, base64::Config {
char_set: base64::CharacterSet::Standard,
newline: base64::Newline::LF,
pad: false,
line_length: None
})
}
pub fn sized_urlsafe(length: usize) -> Result<TextNonce,String> {
TextNonce::sized_configured(length, base64::Config {
char_set: base64::CharacterSet::UrlSafe,
newline: base64::Newline::LF,
pad: false,
line_length: None
})
}
pub fn sized_configured(length: usize, config: base64::Config) -> Result<TextNonce,String> {
if length<16 { return Err("length must be >= 16".to_string()); }
if length % 4 != 0 { return Err("length must be divisible by 4".to_string()); }
let bytelength: usize = (length / 4) * 3;
let mut raw: Vec<u8> = Vec::with_capacity(bytelength);
unsafe { raw.set_len(bytelength); }
let time = ::time::get_time();
unsafe {
let timep: *const u8 = mem::transmute(&time);
ptr::copy_nonoverlapping(timep, raw.as_mut_ptr(), 12);
}
match OsRng::new() {
Ok(mut g) => g.fill_bytes(&mut raw[12..bytelength]),
Err(_) => ::rand::thread_rng().fill_bytes(&mut raw[12..bytelength])
};
Ok(TextNonce(raw.to_base64( config )))
}
pub fn into_string(self) -> String {
let TextNonce(s) = self;
s
}
}
impl fmt::Display for TextNonce {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Display::fmt(&self.0, f)
}
}
#[cfg(test)]
mod tests {
use super::TextNonce;
use std::collections::HashSet;
#[test]
fn new() {
let mut map = HashSet::new();
for _ in (0..100) {
let n = TextNonce::new();
let TextNonce(s) = n;
assert_eq!(s.len(), 32);
assert_eq!( s.chars()
.filter(|x| { x.is_digit(10) || x.is_alphabetic() || *x=='+' || *x=='/' })
.count(),
32 );
map.insert(s);
}
assert_eq!( map.len(), 100 );
}
#[test]
fn sized() {
let n = TextNonce::sized(48);
assert!( n.is_ok() );
let TextNonce(s) = n.unwrap();
assert_eq!(s.len(), 48);
let n = TextNonce::sized(47);
assert!( n.is_err() );
let n = TextNonce::sized(12);
assert!( n.is_err() );
}
}