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use std::hash::Hash;
use std::ops::{Index, Range};
use std::time::Instant;
use crate::algorithms::{diff_deadline, Capture, Compact, Replace};
use crate::{Algorithm, DiffOp};
/// Creates a diff between old and new with the given algorithm capturing the ops.
///
/// This is like [`diff`](crate::algorithms::diff) but instead of using an
/// arbitrary hook this will always use [`Compact`] + [`Replace`] + [`Capture`]
/// and return the captured [`DiffOp`]s.
pub fn capture_diff<Old, New>(
alg: Algorithm,
old: &Old,
old_range: Range<usize>,
new: &New,
new_range: Range<usize>,
) -> Vec<DiffOp>
where
Old: Index<usize> + ?Sized,
New: Index<usize> + ?Sized,
Old::Output: Hash + Eq + Ord,
New::Output: PartialEq<Old::Output> + Hash + Eq + Ord,
{
capture_diff_deadline(alg, old, old_range, new, new_range, None)
}
/// Creates a diff between old and new with the given algorithm capturing the ops.
///
/// Works like [`capture_diff`] but with an optional deadline.
pub fn capture_diff_deadline<Old, New>(
alg: Algorithm,
old: &Old,
old_range: Range<usize>,
new: &New,
new_range: Range<usize>,
deadline: Option<Instant>,
) -> Vec<DiffOp>
where
Old: Index<usize> + ?Sized,
New: Index<usize> + ?Sized,
Old::Output: Hash + Eq + Ord,
New::Output: PartialEq<Old::Output> + Hash + Eq + Ord,
{
let mut d = Compact::new(Replace::new(Capture::new()), old, new);
diff_deadline(alg, &mut d, old, old_range, new, new_range, deadline).unwrap();
d.into_inner().into_inner().into_ops()
}
/// Creates a diff between old and new with the given algorithm capturing the ops.
pub fn capture_diff_slices<T>(alg: Algorithm, old: &[T], new: &[T]) -> Vec<DiffOp>
where
T: Eq + Hash + Ord,
{
capture_diff_slices_deadline(alg, old, new, None)
}
/// Creates a diff between old and new with the given algorithm capturing the ops.
///
/// Works like [`capture_diff_slices`] but with an optional deadline.
pub fn capture_diff_slices_deadline<T>(
alg: Algorithm,
old: &[T],
new: &[T],
deadline: Option<Instant>,
) -> Vec<DiffOp>
where
T: Eq + Hash + Ord,
{
capture_diff_deadline(alg, old, 0..old.len(), new, 0..new.len(), deadline)
}
/// Return a measure of similarity in the range `0..=1`.
///
/// A ratio of `1.0` means the two sequences are a complete match, a
/// ratio of `0.0` would indicate completely distinct sequences. The input
/// is the sequence of diff operations and the length of the old and new
/// sequence.
pub fn get_diff_ratio(ops: &[DiffOp], old_len: usize, new_len: usize) -> f32 {
let matches = ops
.iter()
.map(|op| {
if let DiffOp::Equal { len, .. } = *op {
len
} else {
0
}
})
.sum::<usize>();
let len = old_len + new_len;
if len == 0 {
1.0
} else {
2.0 * matches as f32 / len as f32
}
}
/// Isolate change clusters by eliminating ranges with no changes.
///
/// This will leave holes behind in long periods of equal ranges so that
/// you can build things like unified diffs.
pub fn group_diff_ops(mut ops: Vec<DiffOp>, n: usize) -> Vec<Vec<DiffOp>> {
if ops.is_empty() {
return vec![];
}
let mut pending_group = Vec::new();
let mut rv = Vec::new();
if let Some(DiffOp::Equal {
old_index,
new_index,
len,
}) = ops.first_mut()
{
let offset = (*len).saturating_sub(n);
*old_index += offset;
*new_index += offset;
*len -= offset;
}
if let Some(DiffOp::Equal { len, .. }) = ops.last_mut() {
*len -= (*len).saturating_sub(n);
}
for op in ops.into_iter() {
if let DiffOp::Equal {
old_index,
new_index,
len,
} = op
{
// End the current group and start a new one whenever
// there is a large range with no changes.
if len > n * 2 {
pending_group.push(DiffOp::Equal {
old_index,
new_index,
len: n,
});
rv.push(pending_group);
let offset = len.saturating_sub(n);
pending_group = vec![DiffOp::Equal {
old_index: old_index + offset,
new_index: new_index + offset,
len: len - offset,
}];
continue;
}
}
pending_group.push(op);
}
match &pending_group[..] {
&[] | &[DiffOp::Equal { .. }] => {}
_ => rv.push(pending_group),
}
rv
}
#[test]
fn test_non_string_iter_change() {
use crate::ChangeTag;
let old = vec![1, 2, 3];
let new = vec![1, 2, 4];
let ops = capture_diff_slices(Algorithm::Myers, &old, &new);
let changes: Vec<_> = ops
.iter()
.flat_map(|x| x.iter_changes(&old, &new))
.map(|x| (x.tag(), x.value()))
.collect();
assert_eq!(
changes,
vec![
(ChangeTag::Equal, 1),
(ChangeTag::Equal, 2),
(ChangeTag::Delete, 3),
(ChangeTag::Insert, 4),
]
);
}
|
