Move all crates to a top-level crates folder

Co-Authored-By: Max Brunsfeld <maxbrunsfeld@gmail.com>

crates/buffer/src/anchor.rs

@@ -0,0 +1,77 @@
+use super::{Buffer, Content};
+use anyhow::Result;
+use std::{cmp::Ordering, ops::Range};
+use sum_tree::Bias;
+
+#[derive(Clone, Eq, PartialEq, Debug, Hash)]
+pub struct Anchor {
+    pub offset: usize,
+    pub bias: Bias,
+    pub version: clock::Global,
+}
+
+impl Anchor {
+    pub fn min() -> Self {
+        Self {
+            offset: 0,
+            bias: Bias::Left,
+            version: Default::default(),
+        }
+    }
+
+    pub fn max() -> Self {
+        Self {
+            offset: usize::MAX,
+            bias: Bias::Right,
+            version: Default::default(),
+        }
+    }
+
+    pub fn cmp<'a>(&self, other: &Anchor, buffer: impl Into<Content<'a>>) -> Result<Ordering> {
+        let buffer = buffer.into();
+
+        if self == other {
+            return Ok(Ordering::Equal);
+        }
+
+        let offset_comparison = if self.version == other.version {
+            self.offset.cmp(&other.offset)
+        } else {
+            buffer
+                .full_offset_for_anchor(self)
+                .cmp(&buffer.full_offset_for_anchor(other))
+        };
+
+        Ok(offset_comparison.then_with(|| self.bias.cmp(&other.bias)))
+    }
+
+    pub fn bias_left(&self, buffer: &Buffer) -> Anchor {
+        if self.bias == Bias::Left {
+            self.clone()
+        } else {
+            buffer.anchor_before(self)
+        }
+    }
+
+    pub fn bias_right(&self, buffer: &Buffer) -> Anchor {
+        if self.bias == Bias::Right {
+            self.clone()
+        } else {
+            buffer.anchor_after(self)
+        }
+    }
+}
+
+pub trait AnchorRangeExt {
+    fn cmp<'a>(&self, b: &Range<Anchor>, buffer: impl Into<Content<'a>>) -> Result<Ordering>;
+}
+
+impl AnchorRangeExt for Range<Anchor> {
+    fn cmp<'a>(&self, other: &Range<Anchor>, buffer: impl Into<Content<'a>>) -> Result<Ordering> {
+        let buffer = buffer.into();
+        Ok(match self.start.cmp(&other.start, &buffer)? {
+            Ordering::Equal => other.end.cmp(&self.end, buffer)?,
+            ord @ _ => ord,
+        })
+    }
+}