Added text diff utilities

src/algorithms/mod.rs

@@ -11,12 +11,69 @@
 //! the actual values but only the indexes.  This is why the diff hook is not
 //! used outside of the raw algorithm implementations as for most situations
 //! access to the values is useful of required.
+//!
+//! Most of the crate operates on the [`Algorithm`] enum which abstracts over
+//! the different algorithms.
 
+// general traits and utilities
+mod capture;
 mod hook;
 mod replace;
 
+use std::hash::Hash;
+use std::ops::{Index, Range};
+
+pub use capture::*;
 pub use hook::*;
 pub use replace::*;
 
+// actual diffing algorithms
 pub mod myers;
 pub mod patience;
+
+/// An enum representing a diffing algorithm.
+#[derive(Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord, Debug)]
+pub enum Algorithm {
+    Myers,
+    Patience,
+}
+
+impl Default for Algorithm {
+    /// Returns the default algorithm ([`Algorithm::Myers`]).
+    fn default() -> Algorithm {
+        Algorithm::Myers
+    }
+}
+
+/// Creates a diff between old and new with the given algorithm.
+///
+/// Diffs `old`, between indices `old_range` and `new` between indices `new_range`.
+pub fn diff<Old, New, D>(
+    alg: Algorithm,
+    d: &mut D,
+    old: &Old,
+    old_range: Range<usize>,
+    new: &New,
+    new_range: Range<usize>,
+) -> Result<(), D::Error>
+where
+    Old: Index<usize> + ?Sized,
+    New: Index<usize> + ?Sized,
+    D: DiffHook,
+    Old::Output: Hash + Eq + Ord,
+    New::Output: PartialEq<Old::Output> + Hash + Eq + Ord,
+{
+    match alg {
+        Algorithm::Myers => myers::diff(d, old, old_range, new, new_range),
+        Algorithm::Patience => patience::diff(d, old, old_range, new, new_range),
+    }
+}
+
+/// Shortcut for diffing slices with a specific algorithm.
+pub fn diff_slices<D, T>(alg: Algorithm, d: &mut D, old: &[T], new: &[T]) -> Result<(), D::Error>
+where
+    D: DiffHook,
+    T: Eq + Hash + Ord,
+{
+    diff(alg, d, old, 0..old.len(), new, 0..new.len())
+}