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//! Utilities.
#[macro_use]
mod eco_string;
mod mac_roman;
mod prehashed;
pub use eco_string::EcoString;
pub use mac_roman::decode_mac_roman;
pub use prehashed::Prehashed;
use std::cmp::Ordering;
use std::fmt::{self, Debug, Formatter};
use std::ops::Range;
use std::path::{Component, Path, PathBuf};
use std::sync::Arc;
/// Turn a closure into a struct implementing [`Debug`].
pub fn debug<F>(f: F) -> impl Debug
where
F: Fn(&mut Formatter) -> fmt::Result,
{
struct Wrapper<F>(F);
impl<F> Debug for Wrapper<F>
where
F: Fn(&mut Formatter) -> fmt::Result,
{
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
self.0(f)
}
}
Wrapper(f)
}
/// Additional methods for strings.
pub trait StrExt {
/// The number of code units this string would use if it was encoded in
/// UTF16. This runs in linear time.
fn len_utf16(&self) -> usize;
}
impl StrExt for str {
fn len_utf16(&self) -> usize {
self.chars().map(char::len_utf16).sum()
}
}
/// Additional methods for options.
pub trait OptionExt<T> {
/// Sets `other` as the value if `self` is `None` or if it contains a value
/// larger than `other`.
fn set_min(&mut self, other: T)
where
T: Ord;
/// Sets `other` as the value if `self` is `None` or if it contains a value
/// smaller than `other`.
fn set_max(&mut self, other: T)
where
T: Ord;
}
impl<T> OptionExt<T> for Option<T> {
fn set_min(&mut self, other: T)
where
T: Ord,
{
if self.as_ref().map_or(true, |x| other < *x) {
*self = Some(other);
}
}
fn set_max(&mut self, other: T)
where
T: Ord,
{
if self.as_ref().map_or(true, |x| other > *x) {
*self = Some(other);
}
}
}
/// Additional methods for reference-counted pointers.
pub trait ArcExt<T> {
/// Takes the inner value if there is exactly one strong reference and
/// clones it otherwise.
fn take(self) -> T;
}
impl<T> ArcExt<T> for Arc<T>
where
T: Clone,
{
fn take(self) -> T {
match Arc::try_unwrap(self) {
Ok(v) => v,
Err(rc) => (*rc).clone(),
}
}
}
/// Additional methods for slices.
pub trait SliceExt<T> {
/// Find consecutive runs of the same elements in a slice and yield for
/// each such run the element and number of times it appears.
fn group(&self) -> Group<'_, T>
where
T: PartialEq;
/// Split a slice into consecutive runs with the same key and yield for
/// each such run the key and the slice of elements with that key.
fn group_by_key<K, F>(&self, f: F) -> GroupByKey<'_, T, F>
where
F: FnMut(&T) -> K,
K: PartialEq;
}
impl<T> SliceExt<T> for [T] {
fn group(&self) -> Group<'_, T> {
Group { slice: self }
}
fn group_by_key<K, F>(&self, f: F) -> GroupByKey<'_, T, F> {
GroupByKey { slice: self, f }
}
}
/// This struct is created by [`SliceExt::group`].
pub struct Group<'a, T> {
slice: &'a [T],
}
impl<'a, T> Iterator for Group<'a, T>
where
T: PartialEq,
{
type Item = (&'a T, usize);
fn next(&mut self) -> Option<Self::Item> {
let mut iter = self.slice.iter();
let first = iter.next()?;
let count = 1 + iter.take_while(|&t| t == first).count();
self.slice = &self.slice[count ..];
Some((first, count))
}
}
/// This struct is created by [`SliceExt::group_by_key`].
pub struct GroupByKey<'a, T, F> {
slice: &'a [T],
f: F,
}
impl<'a, T, K, F> Iterator for GroupByKey<'a, T, F>
where
F: FnMut(&T) -> K,
K: PartialEq,
{
type Item = (K, &'a [T]);
fn next(&mut self) -> Option<Self::Item> {
let mut iter = self.slice.iter();
let key = (self.f)(iter.next()?);
let count = 1 + iter.take_while(|t| (self.f)(t) == key).count();
let (head, tail) = self.slice.split_at(count);
self.slice = tail;
Some((key, head))
}
}
/// Additional methods for [`Range<usize>`].
pub trait RangeExt {
/// Locate a position relative to a range.
///
/// This can be used for binary searching the range that contains the
/// position as follows:
/// ```
/// # use typst::util::RangeExt;
/// assert_eq!(
/// [1..2, 2..7, 7..10].binary_search_by(|r| r.locate(5)),
/// Ok(1),
/// );
/// ```
fn locate(&self, pos: usize) -> Ordering;
}
impl RangeExt for Range<usize> {
fn locate(&self, pos: usize) -> Ordering {
if pos < self.start {
Ordering::Greater
} else if pos < self.end {
Ordering::Equal
} else {
Ordering::Less
}
}
}
/// Additional methods for [`Path`].
pub trait PathExt {
/// Lexically normalize a path.
fn normalize(&self) -> PathBuf;
}
impl PathExt for Path {
fn normalize(&self) -> PathBuf {
let mut out = PathBuf::new();
for component in self.components() {
match component {
Component::CurDir => {}
Component::ParentDir => match out.components().next_back() {
Some(Component::Normal(_)) => {
out.pop();
}
_ => out.push(component),
},
_ => out.push(component),
}
}
out
}
}
|
