433 lines
14 KiB
Rust
433 lines
14 KiB
Rust
//! Types dealing with ranges of values
|
|
|
|
extern mod extra;
|
|
|
|
use std::cmp;
|
|
use extra::time::Timespec;
|
|
|
|
/// A trait that normalizes a range bound for a type
|
|
pub trait Normalizable {
|
|
/// Given a range bound, returns the normalized version of that bound. For
|
|
/// discrete types such as i32, the normalized lower bound is always
|
|
/// inclusive and the normalized upper bound is always exclusive. Other
|
|
/// types, such as Timespec, have no normalization process so their
|
|
/// implementation is a no-op.
|
|
///
|
|
/// The logic here should match the logic performed by the equivalent
|
|
/// Postgres type.
|
|
fn normalize<S: BoundSided>(bound: RangeBound<S, Self>)
|
|
-> RangeBound<S, Self>;
|
|
}
|
|
|
|
macro_rules! bounded_normalizable(
|
|
($t:ty) => (
|
|
impl Normalizable for $t {
|
|
fn normalize<S: BoundSided>(bound: RangeBound<S, $t>)
|
|
-> RangeBound<S, $t> {
|
|
match BoundSided::side(None::<S>) {
|
|
Upper if bound.type_ == Inclusive => {
|
|
assert!(bound.value != Bounded::max_value());
|
|
RangeBound::new(bound.value + 1, Exclusive)
|
|
}
|
|
Lower if bound.type_ == Exclusive => {
|
|
assert!(bound.value != Bounded::max_value());
|
|
RangeBound::new(bound.value + 1, Inclusive)
|
|
}
|
|
_ => bound
|
|
}
|
|
}
|
|
}
|
|
)
|
|
)
|
|
|
|
bounded_normalizable!(i32)
|
|
bounded_normalizable!(i64)
|
|
|
|
impl Normalizable for Timespec {
|
|
fn normalize<S: BoundSided>(bound: RangeBound<S, Timespec>)
|
|
-> RangeBound<S, Timespec> {
|
|
bound
|
|
}
|
|
}
|
|
|
|
#[deriving(Eq)]
|
|
enum BoundSide {
|
|
Upper,
|
|
Lower
|
|
}
|
|
|
|
trait BoundSided {
|
|
// param is a hack to get around lack of hints for self type
|
|
fn side(_: Option<Self>) -> BoundSide;
|
|
}
|
|
|
|
/// A tag type representing an upper bound
|
|
#[deriving(Eq,Clone)]
|
|
pub struct UpperBound;
|
|
|
|
/// A tag type representing a lower bound
|
|
#[deriving(Eq,Clone)]
|
|
pub struct LowerBound;
|
|
|
|
impl BoundSided for UpperBound {
|
|
fn side(_: Option<UpperBound>) -> BoundSide {
|
|
Upper
|
|
}
|
|
}
|
|
|
|
impl BoundSided for LowerBound {
|
|
fn side(_: Option<LowerBound>) -> BoundSide {
|
|
Lower
|
|
}
|
|
}
|
|
|
|
/// The type of a range bound
|
|
#[deriving(Eq,Clone)]
|
|
pub enum BoundType {
|
|
/// The bound includes its value
|
|
Inclusive,
|
|
/// The bound excludes its value
|
|
Exclusive
|
|
}
|
|
|
|
/// Represents a one-sided bound.
|
|
///
|
|
/// The side is determined by the `S` phantom parameter.
|
|
#[deriving(Eq,Clone)]
|
|
pub struct RangeBound<S, T> {
|
|
/// The value of the bound
|
|
value: T,
|
|
/// The type of the bound
|
|
type_: BoundType
|
|
}
|
|
|
|
impl<S: BoundSided, T: Ord> Ord for RangeBound<S, T> {
|
|
fn lt(&self, other: &RangeBound<S, T>) -> bool {
|
|
match (BoundSided::side(None::<S>), self.type_, other.type_) {
|
|
(Upper, Exclusive, Inclusive)
|
|
| (Lower, Inclusive, Exclusive) => self.value <= other.value,
|
|
_ => self.value < other.value
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<S: BoundSided, T: Ord> RangeBound<S, T> {
|
|
/// Constructs a new range bound
|
|
pub fn new(value: T, type_: BoundType) -> RangeBound<S, T> {
|
|
RangeBound { value: value, type_: type_ }
|
|
}
|
|
|
|
/// Determines if a value lies within the range specified by this bound.
|
|
pub fn in_bounds(&self, value: &T) -> bool {
|
|
match (self.type_, BoundSided::side(None::<S>)) {
|
|
(Inclusive, Upper) if value <= &self.value => true,
|
|
(Exclusive, Upper) if value < &self.value => true,
|
|
(Inclusive, Lower) if value >= &self.value => true,
|
|
(Exclusive, Lower) if value > &self.value => true,
|
|
_ => false
|
|
}
|
|
}
|
|
}
|
|
|
|
struct OptBound<'self, S, T>(&'self Option<RangeBound<S, T>>);
|
|
|
|
impl<'self, S: BoundSided, T: Ord> Ord for OptBound<'self, S, T> {
|
|
fn lt(&self, other: &OptBound<'self, S, T>) -> bool {
|
|
match (**self, **other) {
|
|
(&None, &None) => false,
|
|
(&None, _) => BoundSided::side(None::<S>) == Lower,
|
|
(_, &None) => BoundSided::side(None::<S>) == Upper,
|
|
(&Some(ref a), &Some(ref b)) => a < b
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Represents a range of values.
|
|
#[deriving(Eq,Clone)]
|
|
pub enum Range<T> {
|
|
priv Empty,
|
|
priv Normal(Option<RangeBound<LowerBound, T>>,
|
|
Option<RangeBound<UpperBound, T>>)
|
|
}
|
|
|
|
impl<T: Ord+Normalizable> Range<T> {
|
|
/// Creates a new range.
|
|
///
|
|
/// If a bound is `None`, the range is unbounded in that direction.
|
|
pub fn new(lower: Option<RangeBound<LowerBound, T>>,
|
|
upper: Option<RangeBound<UpperBound, T>>) -> Range<T> {
|
|
let lower = lower.map(|bound| { Normalizable::normalize(bound) });
|
|
let upper = upper.map(|bound| { Normalizable::normalize(bound) });
|
|
|
|
match (&lower, &upper) {
|
|
(&Some(ref lower), &Some(ref upper)) => {
|
|
let empty = match (lower.type_, upper.type_) {
|
|
(Inclusive, Inclusive) => lower.value > upper.value,
|
|
_ => lower.value >= upper.value
|
|
};
|
|
if empty {
|
|
return Empty;
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
|
|
Normal(lower, upper)
|
|
}
|
|
|
|
/// Creates a new empty range.
|
|
pub fn empty() -> Range<T> {
|
|
Empty
|
|
}
|
|
|
|
/// Determines if this range is the empty range.
|
|
pub fn is_empty(&self) -> bool {
|
|
match *self {
|
|
Empty => true,
|
|
Normal(..) => false
|
|
}
|
|
}
|
|
|
|
/// Returns the lower bound if it exists.
|
|
pub fn lower<'a>(&'a self) -> &'a Option<RangeBound<LowerBound, T>> {
|
|
match *self {
|
|
Empty => &None,
|
|
Normal(ref lower, _) => lower
|
|
}
|
|
}
|
|
|
|
/// Returns the upper bound if it exists.
|
|
pub fn upper<'a>(&'a self) -> &'a Option<RangeBound<UpperBound, T>> {
|
|
match *self {
|
|
Empty => &None,
|
|
Normal(_, ref upper) => upper
|
|
}
|
|
}
|
|
|
|
/// Determines if a value lies within this range.
|
|
pub fn contains(&self, value: &T) -> bool {
|
|
match *self {
|
|
Empty => false,
|
|
Normal(ref lower, ref upper) => {
|
|
lower.as_ref().map_default(true, |b| { b.in_bounds(value) }) &&
|
|
upper.as_ref().map_default(true, |b| { b.in_bounds(value) })
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Determines if a range lies completely within this range.
|
|
pub fn contains_range(&self, other: &Range<T>) -> bool {
|
|
if other.is_empty() {
|
|
return true;
|
|
}
|
|
|
|
if self.is_empty() {
|
|
return false;
|
|
}
|
|
|
|
OptBound(self.lower()) <= OptBound(other.lower()) &&
|
|
OptBound(self.upper()) >= OptBound(other.upper())
|
|
}
|
|
}
|
|
|
|
impl<T: Ord+Normalizable+Clone> Range<T> {
|
|
/// Returns the intersection of this range with another
|
|
pub fn intersect(&self, other: &Range<T>) -> Range<T> {
|
|
if self.is_empty() || other.is_empty() {
|
|
return Range::empty();
|
|
}
|
|
|
|
let lower = cmp::max(OptBound(self.lower()), OptBound(other.lower()))
|
|
.clone();
|
|
let upper = cmp::min(OptBound(self.upper()), OptBound(other.upper()))
|
|
.clone();
|
|
|
|
Range::new(lower, upper)
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod test {
|
|
use super::*;
|
|
|
|
#[test]
|
|
fn test_range_bound_lower_lt() {
|
|
fn check(val1: int, inc1: BoundType, val2: int, inc2: BoundType, expected: bool) {
|
|
let a: RangeBound<LowerBound, int> = RangeBound::new(val1, inc1);
|
|
let b: RangeBound<LowerBound, int> = RangeBound::new(val2, inc2);
|
|
assert_eq!(expected, a < b);
|
|
}
|
|
|
|
check(1, Inclusive, 2, Exclusive, true);
|
|
check(1, Exclusive, 2, Inclusive, true);
|
|
check(1, Inclusive, 1, Exclusive, true);
|
|
check(2, Inclusive, 1, Inclusive, false);
|
|
check(2, Exclusive, 1, Exclusive, false);
|
|
check(1, Exclusive, 1, Inclusive, false);
|
|
check(1, Exclusive, 1, Exclusive, false);
|
|
check(1, Inclusive, 1, Inclusive, false);
|
|
}
|
|
|
|
#[test]
|
|
fn test_range_bound_upper_lt() {
|
|
fn check(val1: int, inc1: BoundType, val2: int, inc2: BoundType, expected: bool) {
|
|
let a: RangeBound<UpperBound, int> = RangeBound::new(val1, inc1);
|
|
let b: RangeBound<UpperBound, int> = RangeBound::new(val2, inc2);
|
|
assert_eq!(expected, a < b);
|
|
}
|
|
|
|
check(1, Inclusive, 2, Exclusive, true);
|
|
check(1, Exclusive, 2, Exclusive, true);
|
|
check(1, Exclusive, 1, Inclusive, true);
|
|
check(2, Inclusive, 1, Inclusive, false);
|
|
check(2, Exclusive, 1, Exclusive, false);
|
|
check(1, Inclusive, 1, Exclusive, false);
|
|
check(1, Inclusive, 1, Inclusive, false);
|
|
check(1, Exclusive, 1, Exclusive, false);
|
|
}
|
|
|
|
#[test]
|
|
fn test_range_bound_lower_in_bounds() {
|
|
fn check(bound: int, inc: BoundType, val: int, expected: bool) {
|
|
let b: RangeBound<LowerBound, int> = RangeBound::new(bound, inc);
|
|
assert_eq!(expected, b.in_bounds(&val));
|
|
}
|
|
|
|
check(1, Inclusive, 1, true);
|
|
check(1, Exclusive, 1, false);
|
|
check(1, Inclusive, 2, true);
|
|
check(1, Inclusive, 0, false);
|
|
}
|
|
|
|
#[test]
|
|
fn test_range_bound_upper_in_bounds() {
|
|
fn check(bound: int, inc: BoundType, val: int, expected: bool) {
|
|
let b: RangeBound<UpperBound, int> = RangeBound::new(bound, inc);
|
|
assert_eq!(expected, b.in_bounds(&val));
|
|
}
|
|
|
|
check(1, Inclusive, 1, true);
|
|
check(1, Exclusive, 1, false);
|
|
check(1, Inclusive, 2, false);
|
|
check(1, Inclusive, 0, true);
|
|
}
|
|
|
|
#[test]
|
|
fn test_range_contains() {
|
|
let r = Range::new(Some(RangeBound::new(1i32, Inclusive)),
|
|
Some(RangeBound::new(3i32, Inclusive)));
|
|
assert!(!r.contains(&4));
|
|
assert!(r.contains(&3));
|
|
assert!(r.contains(&2));
|
|
assert!(r.contains(&1));
|
|
assert!(!r.contains(&0));
|
|
|
|
let r = Range::new(Some(RangeBound::new(1i32, Exclusive)),
|
|
Some(RangeBound::new(3i32, Exclusive)));
|
|
assert!(!r.contains(&4));
|
|
assert!(!r.contains(&3));
|
|
assert!(r.contains(&2));
|
|
assert!(!r.contains(&1));
|
|
assert!(!r.contains(&0));
|
|
|
|
let r = Range::new(None, Some(RangeBound::new(3i32, Inclusive)));
|
|
assert!(!r.contains(&4));
|
|
assert!(r.contains(&2));
|
|
assert!(r.contains(&Bounded::min_value()));
|
|
|
|
let r = Range::new(Some(RangeBound::new(1i32, Inclusive)), None);
|
|
assert!(r.contains(&Bounded::max_value()));
|
|
assert!(r.contains(&4));
|
|
assert!(!r.contains(&0));
|
|
|
|
let r = Range::new(None, None);
|
|
assert!(r.contains(&Bounded::max_value()));
|
|
assert!(r.contains(&0i32));
|
|
assert!(r.contains(&Bounded::min_value()));
|
|
}
|
|
|
|
#[test]
|
|
fn test_normalize_lower() {
|
|
let r: RangeBound<LowerBound, i32> = RangeBound::new(10i32, Inclusive);
|
|
assert_eq!(RangeBound::new(10i32, Inclusive), Normalizable::normalize(r));
|
|
|
|
let r: RangeBound<LowerBound, i32> = RangeBound::new(10i32, Exclusive);
|
|
assert_eq!(RangeBound::new(11i32, Inclusive), Normalizable::normalize(r));
|
|
}
|
|
|
|
#[test]
|
|
fn test_normalize_upper() {
|
|
let r: RangeBound<UpperBound, i32> = RangeBound::new(10i32, Inclusive);
|
|
assert_eq!(RangeBound::new(11i32, Exclusive), Normalizable::normalize(r));
|
|
|
|
let r: RangeBound<UpperBound, i32> = RangeBound::new(10i32, Exclusive);
|
|
assert_eq!(RangeBound::new(10i32, Exclusive), Normalizable::normalize(r));
|
|
}
|
|
|
|
#[test]
|
|
fn test_range_normalizes() {
|
|
let r1 = Range::new(Some(RangeBound::new(10i32, Exclusive)),
|
|
Some(RangeBound::new(15i32, Inclusive)));
|
|
let r2 = Range::new(Some(RangeBound::new(11i32, Inclusive)),
|
|
Some(RangeBound::new(16i32, Exclusive)));
|
|
assert_eq!(r1, r2);
|
|
}
|
|
|
|
#[test]
|
|
fn test_range_empty() {
|
|
assert!(Range::new(Some(RangeBound::new(9i32, Exclusive)),
|
|
Some(RangeBound::new(10i32, Exclusive))).is_empty());
|
|
assert!(Range::new(Some(RangeBound::new(10i32, Inclusive)),
|
|
Some(RangeBound::new(10i32, Exclusive))).is_empty());
|
|
assert!(Range::new(Some(RangeBound::new(10i32, Exclusive)),
|
|
Some(RangeBound::new(10i32, Inclusive))).is_empty());
|
|
assert!(Range::new(Some(RangeBound::new(10i32, Inclusive)),
|
|
Some(RangeBound::new(9i32, Inclusive))).is_empty());
|
|
}
|
|
|
|
#[test]
|
|
fn test_intersection() {
|
|
let r1 = Range::new(Some(RangeBound::new(10i32, Inclusive)),
|
|
Some(RangeBound::new(15i32, Exclusive)));
|
|
let r2 = Range::new(Some(RangeBound::new(20i32, Exclusive)),
|
|
Some(RangeBound::new(25i32, Inclusive)));
|
|
assert!(r1.intersect(&r2).is_empty());
|
|
assert!(r2.intersect(&r1).is_empty());
|
|
assert_eq!(r1, r1.intersect(&Range::new(None, None)));
|
|
assert_eq!(r1, Range::new(None, None).intersect(&r1));
|
|
|
|
let r2 = Range::new(Some(RangeBound::new(10i32, Exclusive)), None);
|
|
let exp = Range::new(r2.lower().clone(), r1.upper().clone());
|
|
assert_eq!(exp, r1.intersect(&r2));
|
|
assert_eq!(exp, r2.intersect(&r1));
|
|
|
|
let r2 = Range::new(None, Some(RangeBound::new(15i32, Inclusive)));
|
|
assert_eq!(r1, r1.intersect(&r2));
|
|
assert_eq!(r1, r2.intersect(&r1));
|
|
|
|
let r2 = Range::new(Some(RangeBound::new(11i32, Inclusive)),
|
|
Some(RangeBound::new(14i32, Exclusive)));
|
|
assert_eq!(r2, r1.intersect(&r2));
|
|
assert_eq!(r2, r2.intersect(&r1));
|
|
}
|
|
|
|
#[test]
|
|
fn test_contains_range() {
|
|
assert!(Range::<i32>::empty().contains_range(&Range::empty()));
|
|
|
|
let r1 = Range::new(Some(RangeBound::new(10i32, Inclusive)),
|
|
Some(RangeBound::new(15i32, Exclusive)));
|
|
assert!(r1.contains_range(&r1));
|
|
|
|
let r2 = Range::new(Some(RangeBound::new(10i32, Exclusive)),
|
|
None);
|
|
assert!(!r1.contains_range(&r2));
|
|
assert!(!r2.contains_range(&r1));
|
|
|
|
let r2 = Range::new(None,
|
|
Some(RangeBound::new(15i32, Inclusive)));
|
|
assert!(!r1.contains_range(&r2));
|
|
assert!(r2.contains_range(&r1));
|
|
}
|
|
}
|