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use core::ops::Range;
use objc2::encode::{Encode, Encoding, RefEncode};
use crate::NSUInteger;
/// TODO.
///
/// See [Apple's documentation](https://developer.apple.com/documentation/foundation/nsrange?language=objc).
#[repr(C)]
// PartialEq is same as NSEqualRanges
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct NSRange {
/// The lower bound of the range (inclusive).
pub location: NSUInteger,
/// The number of items in the range, starting from `location`.
pub length: NSUInteger,
}
impl NSRange {
/// Create a new range with the given values.
///
/// # Examples
///
/// ```
/// use objc2_foundation::NSRange;
/// assert_eq!(NSRange::new(3, 2), NSRange::from(3..5));
/// ```
#[inline]
#[doc(alias = "NSMakeRange")]
pub const fn new(location: usize, length: usize) -> Self {
// Equivalent to NSMakeRange
Self { location, length }
}
/// Returns `true` if the range contains no items.
///
/// # Examples
///
/// ```
/// use objc2_foundation::NSRange;
///
/// assert!(!NSRange::from(3..5).is_empty());
/// assert!( NSRange::from(3..3).is_empty());
/// ```
#[inline]
pub fn is_empty(&self) -> bool {
self.length == 0
}
/// Returns `true` if the index is within the range.
///
/// # Examples
///
/// ```
/// use objc2_foundation::NSRange;
///
/// assert!(!NSRange::from(3..5).contains(2));
/// assert!( NSRange::from(3..5).contains(3));
/// assert!( NSRange::from(3..5).contains(4));
/// assert!(!NSRange::from(3..5).contains(5));
///
/// assert!(!NSRange::from(3..3).contains(3));
/// ```
#[inline]
#[doc(alias = "NSLocationInRange")]
pub fn contains(&self, index: usize) -> bool {
// Same as NSLocationInRange
if let Some(len) = index.checked_sub(self.location) {
len < self.length
} else {
// index < self.location
false
}
}
/// Returns the upper bound of the range (exclusive).
#[inline]
#[doc(alias = "NSMaxRange")]
pub fn end(&self) -> usize {
self.location
.checked_add(self.length)
.expect("NSRange too large")
}
// TODO: NSUnionRange
// TODO: NSIntersectionRange
}
// Sadly, we can't do this:
// impl RangeBounds<usize> for NSRange {
// fn start_bound(&self) -> Bound<&usize> {
// Bound::Included(&self.location)
// }
// fn end_bound(&self) -> Bound<&usize> {
// Bound::Excluded(&(self.location + self.length))
// }
// }
impl From<Range<usize>> for NSRange {
fn from(range: Range<usize>) -> Self {
let length = range
.end
.checked_sub(range.start)
.expect("Range end < start");
Self {
location: range.start,
length,
}
}
}
impl From<NSRange> for Range<usize> {
#[inline]
fn from(nsrange: NSRange) -> Self {
Self {
start: nsrange.location,
end: nsrange.end(),
}
}
}
unsafe impl Encode for NSRange {
const ENCODING: Encoding = Encoding::Struct("_NSRange", &[usize::ENCODING, usize::ENCODING]);
}
unsafe impl RefEncode for NSRange {
const ENCODING_REF: Encoding = Encoding::Pointer(&Self::ENCODING);
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_from_range() {
let cases: &[(Range<usize>, NSRange)] = &[
(0..0, NSRange::new(0, 0)),
(0..10, NSRange::new(0, 10)),
(10..10, NSRange::new(10, 0)),
(10..20, NSRange::new(10, 10)),
];
for (range, expected) in cases {
assert_eq!(NSRange::from(range.clone()), *expected);
}
}
#[test]
#[should_panic = "Range end < start"]
#[allow(clippy::reversed_empty_ranges)]
fn test_from_range_inverted() {
let _ = NSRange::from(10..0);
}
#[test]
fn test_contains() {
let range = NSRange::from(10..20);
assert!(!range.contains(0));
assert!(!range.contains(9));
assert!(range.contains(10));
assert!(range.contains(11));
assert!(!range.contains(20));
assert!(!range.contains(21));
}
#[test]
fn test_end() {
let range = NSRange::from(10..20);
assert!(!range.contains(0));
assert!(!range.contains(9));
assert!(range.contains(10));
assert!(range.contains(11));
assert!(!range.contains(20));
assert!(!range.contains(21));
}
#[test]
#[should_panic = "NSRange too large"]
fn test_end_large() {
let _ = NSRange::new(usize::MAX, usize::MAX).end();
}
}