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Differential D7982

rust-utils: introduce `subslice_index` function
AbandonedPublic

Authored by Alphare on Jan 24 2020, 5:12 AM.

Details

Reviewers
martinvonz
Group Reviewers
hg-reviewers
Summary

I implemented it for something that did not turn out to need it, maybe it'll be
useful?

Diff Detail

Repository
rHG Mercurial
Branch
default
Lint
No Linters Available
Unit
No Unit Test Coverage

Event Timeline

Alphare created this revision.Jan 24 2020, 5:12 AM
martinvonz requested changes to this revision.Jan 24 2020, 11:45 AM
martinvonz added a subscriber: martinvonz.

Sorry to be dismissive, but please hold on to it until it becomes needed then. I'm strongly against adding dead code unless we know we're at least going to use it soon.

This revision now requires changes to proceed.Jan 24 2020, 11:45 AM
Alphare added a comment.Jan 24 2020, 11:51 AM

Sure, that is completely fine, I'll remove it from the stack.

Alphare abandoned this revision.Jan 24 2020, 11:52 AM
Alphare updated this revision to Diff 19959.Feb 6 2020, 11:48 AM
Alphare abandoned this revision.Feb 6 2020, 11:48 AM

I was certain to have pruned this one. I'll do it.

Revision Contents
Changeset List

PathPackages
Mrust/hg-core/src/utils.rs (30 lines)

Diff 19547

rust/hg-core/src/utils.rs

} }
for i in 0..=buf.len() - from.len() { for i in 0..=buf.len() - from.len() {
if buf[i..].starts_with(from) { if buf[i..].starts_with(from) {
buf[i..(i + from.len())].clone_from_slice(to); buf[i..(i + from.len())].clone_from_slice(to);
} }
} }
} }
/// Find the offset of the subslice relative to the original collection
///
/// This function panics for zero-sized types.
/// # Examples:
///
/// ```
/// use crate::hg::utils::subslice_offset;
/// let mut line = b"Subslice me!".to_vec();
/// assert_eq!(subslice_offset(&line, &line[8..]), Some(8));
///
/// assert_eq!(subslice_offset(&line, b"hahaha"), None);
///
/// // Empty array
/// let v: [u8; 0] = [];
/// assert_eq!(subslice_offset(&v, &v), Some(0));
/// assert_eq!(subslice_offset(&v, b"hehe"), None);
/// ```
pub fn subslice_offset<T: Sized>(outer: &[T], inner: &[T]) -> Option<usize> {
let pointee_size = std::mem::size_of::<T>();
assert!(0 < pointee_size && pointee_size <= isize::max_value() as usize);
let outer_start = outer.as_ptr() as usize;
let inner = inner.as_ptr() as usize;
if inner < outer_start || inner > outer_start.wrapping_add(outer.len()) {
None
} else {
Some(inner.wrapping_sub(outer_start))
}
}
pub trait SliceExt { pub trait SliceExt {
fn trim_end(&self) -> &Self; fn trim_end(&self) -> &Self;
fn trim_start(&self) -> &Self; fn trim_start(&self) -> &Self;
fn trim(&self) -> &Self; fn trim(&self) -> &Self;
fn drop_prefix(&self, needle: &Self) -> Option<&Self>; fn drop_prefix(&self, needle: &Self) -> Option<&Self>;
} }
fn is_not_whitespace(c: &u8) -> bool { fn is_not_whitespace(c: &u8) -> bool {