rust/src/libsyntax/opt_vec.rs

196 lines
4.8 KiB
Rust
Raw Normal View History

// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
/*!
*
* Defines a type OptVec<T> that can be used in place of ~[T].
* OptVec avoids the need for allocation for empty vectors.
* OptVec implements the iterable interface as well as
* other useful things like `push()` and `len()`.
*/
use core::prelude::*;
use core::iter;
use core::iter::BaseIter;
#[auto_encode]
#[auto_decode]
pub enum OptVec<T> {
Empty,
Vec(~[T])
}
pub fn with<T>(+t: T) -> OptVec<T> {
Vec(~[t])
}
pub fn from<T>(+t: ~[T]) -> OptVec<T> {
if t.len() == 0 {
Empty
} else {
Vec(t)
}
}
impl<T> OptVec<T> {
fn push(&mut self, +t: T) {
match *self {
Vec(ref mut v) => {
v.push(t);
return;
}
Empty => {}
}
// FIXME(#5074): flow insensitive means we can't move
// assignment inside `match`
*self = Vec(~[t]);
}
fn map<U>(&self, op: &fn(&T) -> U) -> OptVec<U> {
match *self {
Empty => Empty,
Vec(ref v) => Vec(v.map(op))
}
}
pure fn get(&self, i: uint) -> &'self T {
match *self {
Empty => fail!(fmt!("Invalid index %u", i)),
Vec(ref v) => &v[i]
}
}
pure fn is_empty(&self) -> bool {
self.len() == 0
}
pure fn len(&self) -> uint {
match *self {
Empty => 0,
Vec(ref v) => v.len()
}
}
}
pub fn take_vec<T>(+v: OptVec<T>) -> ~[T] {
match v {
Empty => ~[],
Vec(v) => v
}
}
impl<T:Copy> OptVec<T> {
fn prepend(&self, +t: T) -> OptVec<T> {
let mut v0 = ~[t];
match *self {
Empty => {}
Vec(ref v1) => { v0.push_all(*v1); }
}
return Vec(v0);
}
fn push_all<I: BaseIter<T>>(&mut self, from: &I) {
for from.each |e| {
self.push(copy *e);
}
}
}
impl<A:Eq> Eq for OptVec<A> {
pure fn eq(&self, other: &OptVec<A>) -> bool {
// Note: cannot use #[deriving(Eq)] here because
// (Empty, Vec(~[])) ought to be equal.
match (self, other) {
(&Empty, &Empty) => true,
(&Empty, &Vec(ref v)) => v.is_empty(),
(&Vec(ref v), &Empty) => v.is_empty(),
(&Vec(ref v1), &Vec(ref v2)) => *v1 == *v2
}
}
pure fn ne(&self, other: &OptVec<A>) -> bool {
!self.eq(other)
}
}
impl<A> BaseIter<A> for OptVec<A> {
pure fn each(&self, blk: &fn(v: &A) -> bool) {
match *self {
Empty => {}
Vec(ref v) => v.each(blk)
}
}
pure fn size_hint(&self) -> Option<uint> {
Some(self.len())
}
}
impl<A> iter::ExtendedIter<A> for OptVec<A> {
#[inline(always)]
pure fn eachi(&self, blk: &fn(+v: uint, v: &A) -> bool) {
iter::eachi(self, blk)
}
#[inline(always)]
pure fn all(&self, blk: &fn(&A) -> bool) -> bool {
iter::all(self, blk)
}
#[inline(always)]
pure fn any(&self, blk: &fn(&A) -> bool) -> bool {
iter::any(self, blk)
}
#[inline(always)]
pure fn foldl<B>(&self, +b0: B, blk: &fn(&B, &A) -> B) -> B {
iter::foldl(self, b0, blk)
}
#[inline(always)]
pure fn position(&self, f: &fn(&A) -> bool) -> Option<uint> {
iter::position(self, f)
}
#[inline(always)]
pure fn map_to_vec<B>(&self, op: &fn(&A) -> B) -> ~[B] {
iter::map_to_vec(self, op)
}
#[inline(always)]
pure fn flat_map_to_vec<B,IB:BaseIter<B>>(&self, op: &fn(&A) -> IB)
-> ~[B] {
iter::flat_map_to_vec(self, op)
}
}
impl<A: Eq> iter::EqIter<A> for OptVec<A> {
#[inline(always)]
pure fn contains(&self, x: &A) -> bool { iter::contains(self, x) }
#[inline(always)]
pure fn count(&self, x: &A) -> uint { iter::count(self, x) }
}
impl<A: Copy> iter::CopyableIter<A> for OptVec<A> {
#[inline(always)]
pure fn filter_to_vec(&self, pred: &fn(&A) -> bool) -> ~[A] {
iter::filter_to_vec(self, pred)
}
#[inline(always)]
pure fn to_vec(&self) -> ~[A] { iter::to_vec(self) }
#[inline(always)]
pure fn find(&self, f: &fn(&A) -> bool) -> Option<A> {
iter::find(self, f)
}
}
impl<A: Copy+Ord> iter::CopyableOrderedIter<A> for OptVec<A> {
#[inline(always)]
pure fn min(&self) -> A { iter::min(self) }
#[inline(always)]
pure fn max(&self) -> A { iter::max(self) }
}