use std::collections::hash_map::{HashMap, self};
use std::hash::{Hash, Hasher};
use std::iter::range;
use std::mem;
use std::num::{self, Int, SignedInt, UnsignedInt};
use std::rand::Rng;
#[cfg(feature = "collect_impls")]
use collect::TrieMap;
pub trait Gen : Rng {
fn size(&self) -> usize;
}
pub struct StdGen<R> {
rng: R,
size: usize,
}
impl<R: Rng> StdGen<R> {
pub fn new(rng: R, size: usize) -> StdGen<R> {
StdGen { rng: rng, size: size }
}
}
impl<R: Rng> Rng for StdGen<R> {
fn next_u32(&mut self) -> u32 { self.rng.next_u32() }
fn next_u64(&mut self) -> u64 { self.rng.next_u64() }
fn fill_bytes(&mut self, dest: &mut [u8]) { self.rng.fill_bytes(dest) }
}
impl<R: Rng> Gen for StdGen<R> {
fn size(&self) -> usize { self.size }
}
pub trait Shrinker<A> {
fn next_shrink(&mut self) -> Option<A>;
}
impl<A> Iterator for Box<Shrinker<A>+'static> {
type Item = A;
fn next(&mut self) -> Option<A> { (**self).next_shrink() }
}
impl<T, A: Iterator<Item=T>> Shrinker<T> for A {
fn next_shrink(&mut self) -> Option<T> { self.next() }
}
struct EmptyShrinker<A>;
impl<A> Iterator for EmptyShrinker<A> {
type Item = A;
fn next(&mut self) -> Option<A> { None }
}
pub fn empty_shrinker<A>() -> Box<Shrinker<A>+'static> {
Box::new(EmptyShrinker)
}
struct SingleShrinker<A> {
value: Option<A>
}
impl<A> Iterator for SingleShrinker<A> {
type Item = A;
fn next(&mut self) -> Option<A> { mem::replace(&mut self.value, None) }
}
pub fn single_shrinker<A: 'static>(value: A) -> Box<Shrinker<A>+'static> {
Box::new(SingleShrinker { value: Some(value) })
}
pub trait Arbitrary : Clone + Send {
fn arbitrary<G: Gen>(g: &mut G) -> Self;
fn shrink(&self) -> Box<Shrinker<Self>+'static> {
empty_shrinker()
}
}
impl Arbitrary for () {
fn arbitrary<G: Gen>(_: &mut G) -> () { () }
}
impl Arbitrary for bool {
fn arbitrary<G: Gen>(g: &mut G) -> bool { g.gen() }
fn shrink(&self) -> Box<Shrinker<bool>+'static> {
match *self {
true => single_shrinker(false),
false => empty_shrinker(),
}
}
}
impl<A: Arbitrary> Arbitrary for Option<A> {
fn arbitrary<G: Gen>(g: &mut G) -> Option<A> {
if g.gen() {
None
} else {
Some(Arbitrary::arbitrary(g))
}
}
fn shrink(&self) -> Box<Shrinker<Option<A>>+'static> {
match *self {
None => {
empty_shrinker()
}
Some(ref x) => {
let chain = single_shrinker(None).chain(x.shrink().map(Some));
Box::new(chain) as Box<Shrinker<Option<A>>+'static>
}
}
}
}
impl<A: Arbitrary, B: Arbitrary> Arbitrary for Result<A, B> {
fn arbitrary<G: Gen>(g: &mut G) -> Result<A, B> {
if g.gen() {
Ok(Arbitrary::arbitrary(g))
} else {
Err(Arbitrary::arbitrary(g))
}
}
fn shrink(&self) -> Box<Shrinker<Result<A, B>>+'static> {
match *self {
Ok(ref x) => {
let xs: Box<Shrinker<A>+'static> = x.shrink();
let tagged = xs.map(Ok);
Box::new(tagged) as Box<Shrinker<Result<A, B>>+'static>
}
Err(ref x) => {
let xs: Box<Shrinker<B>+'static> = x.shrink();
let tagged = xs.map(Err);
Box::new(tagged) as Box<Shrinker<Result<A, B>>+'static>
}
}
}
}
macro_rules! impl_arb_for_tuple {
(($var_a:ident, $type_a:ident) $(, ($var_n:ident, $type_n:ident))*) => (
impl<$type_a: Arbitrary, $($type_n: Arbitrary),*> Arbitrary
for ($type_a, $($type_n),*) {
fn arbitrary<GEN: Gen>(g: &mut GEN) -> ($type_a, $($type_n),*) {
(
Arbitrary::arbitrary(g),
$({
let arb: $type_n = Arbitrary::arbitrary(g);
arb
},
)*
)
}
fn shrink(&self)
-> Box<Shrinker<($type_a, $($type_n),*)> + 'static> {
let (ref $var_a, $(ref $var_n),*) = *self;
let sa = $var_a.shrink().scan(
($($var_n.clone(),)*),
|&mut ($(ref $var_n,)*), $var_a|
Some(($var_a, $($var_n.clone(),)*))
);
let srest = ($($var_n.clone(),)*).shrink()
.scan($var_a.clone(), |$var_a, ($($var_n,)*)|
Some(($var_a.clone(), $($var_n,)*))
);
Box::new(sa.chain(srest))
}
}
);
}
impl_arb_for_tuple!((a, A));
impl_arb_for_tuple!((a, A), (b, B));
impl_arb_for_tuple!((a, A), (b, B), (c, C));
impl_arb_for_tuple!((a, A), (b, B), (c, C), (d, D));
impl_arb_for_tuple!((a, A), (b, B), (c, C), (d, D), (e, E));
impl_arb_for_tuple!((a, A), (b, B), (c, C), (d, D), (e, E), (f, F));
impl_arb_for_tuple!((a, A), (b, B), (c, C), (d, D), (e, E), (f, F),
(g, G));
impl_arb_for_tuple!((a, A), (b, B), (c, C), (d, D), (e, E), (f, F),
(g, G), (h, H));
impl_arb_for_tuple!((a, A), (b, B), (c, C), (d, D), (e, E), (f, F),
(g, G), (h, H), (i, I));
impl_arb_for_tuple!((a, A), (b, B), (c, C), (d, D), (e, E), (f, F),
(g, G), (h, H), (i, I), (j, J));
impl_arb_for_tuple!((a, A), (b, B), (c, C), (d, D), (e, E), (f, F),
(g, G), (h, H), (i, I), (j, J), (k, K));
impl_arb_for_tuple!((a, A), (b, B), (c, C), (d, D), (e, E), (f, F),
(g, G), (h, H), (i, I), (j, J), (k, K), (l, L));
impl<A: Arbitrary> Arbitrary for Vec<A> {
fn arbitrary<G: Gen>(g: &mut G) -> Vec<A> {
let size = { let s = g.size(); g.gen_range(0, s) };
range(0, size).map(|_| Arbitrary::arbitrary(g)).collect()
}
fn shrink(&self) -> Box<Shrinker<Vec<A>>+'static> {
if self.len() == 0 {
return empty_shrinker();
}
let mut xs: Vec<Vec<A>> = vec![vec![]];
let mut k = self.len() / 2;
while k > 0 {
xs.extend(shuffle_vec(&**self, k).into_iter());
k = k / 2;
}
for (i, x) in self.iter().enumerate() {
for sx in x.shrink() {
let mut change_one = self.clone();
change_one[i] = sx;
xs.push(change_one);
}
}
Box::new(xs.into_iter())
}
}
#[cfg(feature = "collect_impls")]
impl<A: Arbitrary> Arbitrary for TrieMap<A> {
fn arbitrary<G: Gen>(g: &mut G) -> TrieMap<A> {
let vec: Vec<(usize, A)> = Arbitrary::arbitrary(g);
vec.into_iter().collect()
}
fn shrink(&self) -> Box<Shrinker<TrieMap<A>>+'static> {
let vec: Vec<(usize, A)> = self.iter()
.map(|(a, b)| (a, b.clone()))
.collect();
Box::new(vec.shrink().map(|v| v.into_iter().collect::<TrieMap<A>>()))
}
}
impl<K: Arbitrary + Eq + Hash<hash_map::Hasher>, V: Arbitrary> Arbitrary for HashMap<K, V> {
fn arbitrary<G: Gen>(g: &mut G) -> HashMap<K, V> {
let vec: Vec<(K, V)> = Arbitrary::arbitrary(g);
vec.into_iter().collect()
}
fn shrink(&self) -> Box<Shrinker<HashMap<K, V>>+'static> {
let vec: Vec<(K, V)> = self.clone().into_iter().collect();
Box::new(vec.shrink().map(|v| v.into_iter().collect::<HashMap<K, V>>()))
}
}
impl Arbitrary for String {
fn arbitrary<G: Gen>(g: &mut G) -> String {
let size = { let s = g.size(); g.gen_range(0, s) };
g.gen_ascii_chars().take(size).collect()
}
fn shrink(&self) -> Box<Shrinker<String>+'static> {
let chars: Vec<char> = self.chars().collect();
Box::new(chars.shrink().map(|x| x.into_iter().collect::<String>()))
}
}
impl Arbitrary for char {
fn arbitrary<G: Gen>(g: &mut G) -> char { g.gen() }
fn shrink(&self) -> Box<Shrinker<char>+'static> {
empty_shrinker()
}
}
macro_rules! signed_arbitrary {
($($ty:ty),*) => {
$(
impl Arbitrary for $ty {
fn arbitrary<G: Gen>(g: &mut G) -> $ty {
let s = g.size(); g.gen_range(-(s as $ty), s as $ty)
}
fn shrink(&self) -> Box<Shrinker<$ty>+'static> {
SignedShrinker::new(*self)
}
}
)*
}
}
signed_arbitrary! {
isize, i8, i16, i32, i64
}
macro_rules! unsigned_arbitrary {
($($ty:ty),*) => {
$(
impl Arbitrary for $ty {
fn arbitrary<G: Gen>(g: &mut G) -> $ty {
let s = g.size(); g.gen_range(0, s as $ty)
}
fn shrink(&self) -> Box<Shrinker<$ty>+'static> {
UnsignedShrinker::new(*self)
}
}
)*
}
}
unsigned_arbitrary! {
usize, u8, u16, u32, u64
}
impl Arbitrary for f32 {
fn arbitrary<G: Gen>(g: &mut G) -> f32 {
let s = g.size(); g.gen_range(-(s as f32), s as f32)
}
fn shrink(&self) -> Box<Shrinker<f32>+'static> {
let it = SignedShrinker::new(*self as i32);
Box::new(it.map(|x| x as f32))
}
}
impl Arbitrary for f64 {
fn arbitrary<G: Gen>(g: &mut G) -> f64 {
let s = g.size(); g.gen_range(-(s as f64), s as f64)
}
fn shrink(&self) -> Box<Shrinker<f64>+'static> {
let it = SignedShrinker::new(*self as i64);
Box::new(it.map(|x| x as f64))
}
}
fn shuffle_vec<A: Clone>(xs: &[A], k: usize) -> Vec<Vec<A>> {
fn shuffle<A: Clone>(xs: &[A], k: usize, n: usize) -> Vec<Vec<A>> {
if k > n {
return vec![];
}
let xs1: Vec<A> = xs[..k].iter().map(|x| x.clone()).collect();
let xs2: Vec<A> = xs[k..].iter().map(|x| x.clone()).collect();
if xs2.len() == 0 {
return vec![vec![]];
}
let cat = |&mut: x: &Vec<A>| {
let mut pre = xs1.clone();
pre.extend(x.clone().into_iter());
pre
};
let shuffled = shuffle(&*xs2, k, n-k);
let mut more: Vec<Vec<A>> = shuffled.iter().map(cat).collect();
more.insert(0, xs2);
more
}
shuffle(xs, k, xs.len())
}
fn half<A: Int>(x: A) -> A { x / num::cast(2is).unwrap() }
struct SignedShrinker<A> {
x: A,
i: A,
}
impl<A: SignedInt + Send> SignedShrinker<A> {
fn new(x: A) -> Box<Shrinker<A>+'static> {
if x == Int::zero() {
empty_shrinker()
} else {
let shrinker = SignedShrinker {
x: x,
i: half(x),
};
if shrinker.i.is_negative() {
Box::new(vec![Int::zero(), shrinker.x.abs()].into_iter().chain(shrinker))
} else {
Box::new(vec![Int::zero()].into_iter().chain(shrinker))
}
}
}
}
impl<A: SignedInt> Iterator for SignedShrinker<A> {
type Item = A;
fn next(&mut self) -> Option<A> {
if (self.x - self.i).abs() < self.x.abs() {
let result = Some(self.x - self.i);
self.i = half(self.i);
result
} else {
None
}
}
}
struct UnsignedShrinker<A> {
x: A,
i: A,
}
impl<A: UnsignedInt + Send> UnsignedShrinker<A> {
fn new(x: A) -> Box<Shrinker<A>+'static> {
if x == Int::zero() {
empty_shrinker::<A>()
} else {
Box::new(vec![Int::zero()].into_iter().chain(
UnsignedShrinker {
x: x,
i: half(x),
}
))
}
}
}
impl<A: UnsignedInt> Iterator for UnsignedShrinker<A> {
type Item = A;
fn next(&mut self) -> Option<A> {
if self.x - self.i < self.x {
let result = Some(self.x - self.i);
self.i = half(self.i);
result
} else {
None
}
}
}
#[cfg(test)]
mod test {
use std::collections::hash_map;
use std::collections::{HashMap, HashSet};
use std::fmt::Debug;
use std::hash::Hash;
use std::iter;
use std::rand;
use super::Arbitrary;
#[cfg(feature = "collect_impls")]
use collect::TrieMap;
#[test]
fn arby_unit() {
assert_eq!(arby::<()>(), ());
}
#[test]
fn arby_int() {
rep(&mut || { let n: isize = arby(); assert!(n >= -5 && n <= 5); } );
}
#[test]
fn arby_uint() {
rep(&mut || { let n: usize = arby(); assert!(n <= 5); } );
}
fn arby<A: super::Arbitrary>() -> A {
super::Arbitrary::arbitrary(&mut gen())
}
fn gen() -> super::StdGen<rand::ThreadRng> {
super::StdGen::new(rand::thread_rng(), 5)
}
fn rep<F>(f: &mut F) where F : FnMut() -> () {
for _ in iter::range(0us, 100) {
f()
}
}
#[test]
fn unit() {
eq((), vec![]);
}
#[test]
fn bools() {
eq(false, vec![]);
eq(true, vec![false]);
}
#[test]
fn options() {
eq(None::<()>, vec![]);
eq(Some(false), vec![None]);
eq(Some(true), vec![None, Some(false)]);
}
#[test]
fn results() {
ordered_eq(Ok::<bool, ()>(true), vec![Ok(false)]);
ordered_eq(Err::<(), bool>(true), vec![Err(false)]);
}
#[test]
fn tuples() {
eq((false, false), vec![]);
eq((true, false), vec![(false, false)]);
eq((true, true), vec![(false, true), (true, false)]);
}
#[test]
fn triples() {
eq((false, false, false), vec![]);
eq((true, false, false), vec![(false, false, false)]);
eq((true, true, false),
vec![(false, true, false), (true, false, false)]);
}
#[test]
fn quads() {
eq((false, false, false, false), vec![]);
eq((true, false, false, false), vec![(false, false, false, false)]);
eq((true, true, false, false),
vec![(false, true, false, false), (true, false, false, false)]);
}
#[test]
fn ints() {
eq(5is, vec![0, 3, 4]);
eq(-5is, vec![5, 0, -3, -4]);
eq(0is, vec![]);
}
#[test]
fn ints8() {
eq(5i8, vec![0, 3, 4]);
eq(-5i8, vec![5, 0, -3, -4]);
eq(0i8, vec![]);
}
#[test]
fn ints16() {
eq(5i16, vec![0, 3, 4]);
eq(-5i16, vec![5, 0, -3, -4]);
eq(0i16, vec![]);
}
#[test]
fn ints32() {
eq(5i32, vec![0, 3, 4]);
eq(-5i32, vec![5, 0, -3, -4]);
eq(0i32, vec![]);
}
#[test]
fn ints64() {
eq(5i64, vec![0, 3, 4]);
eq(-5i64, vec![5, 0, -3, -4]);
eq(0i64, vec![]);
}
#[test]
fn uints() {
eq(5us, vec![0, 3, 4]);
eq(0us, vec![]);
}
#[test]
fn uints8() {
eq(5u8, vec![0, 3, 4]);
eq(0u8, vec![]);
}
#[test]
fn uints16() {
eq(5u16, vec![0, 3, 4]);
eq(0u16, vec![]);
}
#[test]
fn uints32() {
eq(5u32, vec![0, 3, 4]);
eq(0u32, vec![]);
}
#[test]
fn uints64() {
eq(5u64, vec![0, 3, 4]);
eq(0u64, vec![]);
}
#[test]
fn vecs() {
eq({let it: Vec<isize> = vec![]; it}, vec![]);
eq({let it: Vec<Vec<isize>> = vec![vec![]]; it}, vec![vec![]]);
eq(vec![1is], vec![vec![], vec![0]]);
eq(vec![11is], vec![vec![], vec![0], vec![6], vec![9], vec![10]]);
eq(
vec![3is, 5],
vec![vec![], vec![5], vec![3], vec![0,5], vec![2,5],
vec![3,0], vec![3,3], vec![3,4]]
);
}
#[cfg(feature = "collect_impls")]
#[test]
fn triemaps() {
eq({let it: TrieMap<isize> = TrieMap::new(); it}, vec![]);
{
let mut map = TrieMap::new();
map.insert(1, 1i);
let shrinks = vec![
{let mut m = TrieMap::new(); m.insert(1, 0is); m},
{let mut m = TrieMap::new(); m.insert(0, 1is); m},
TrieMap::new()
];
eq(map, shrinks);
}
}
#[test]
fn hashmaps() {
ordered_eq({let it: HashMap<usize, isize> = HashMap::new(); it}, vec![]);
{
let mut map = HashMap::new();
map.insert(1us, 1is);
let shrinks = vec![
HashMap::new(),
{let mut m = HashMap::new(); m.insert(0, 1); m},
{let mut m = HashMap::new(); m.insert(1, 0); m},
];
ordered_eq(map, shrinks);
}
}
#[test]
fn chars() {
eq('a', vec![]);
}
#[test]
fn strs() {
eq("".to_string(), vec![]);
eq("A".to_string(), vec!["".to_string()]);
eq("ABC".to_string(), vec!["".to_string(),
"AB".to_string(),
"BC".to_string(),
"AC".to_string()]);
}
fn eq<A: Arbitrary + Eq + Debug + Hash<hash_map::Hasher>>(s: A, v: Vec<A>) {
let (left, right) = (shrunk(s), set(v));
assert_eq!(left, right);
}
fn shrunk<A: Arbitrary + Eq + Hash<hash_map::Hasher>>(s: A) -> HashSet<A> {
set(s.shrink().collect())
}
fn set<A: Eq + Hash<hash_map::Hasher>>(xs: Vec<A>) -> HashSet<A> {
xs.into_iter().collect()
}
fn ordered_eq<A: Arbitrary + Eq + Debug>(s: A, v: Vec<A>) {
let (left, right) = (s.shrink().collect::<Vec<A>>(), v);
assert_eq!(left, right);
}
}