address review: skip the tab-stop lookup for a NaN position

crates/engine/src/compare.rs

@@ -121,10 +121,9 @@ pub fn diff(cur: &Presentation, rev: &Presentation, by_position: bool) -> Vec<Ch
     let cur_matched: HashSet<usize> = pairs.iter().map(|p| p.0).collect();
     let rev_matched: HashSet<usize> = pairs.iter().map(|p| p.1).collect();
     let mut out = vec![];
-    let mut media = Media::new(cur, rev);
     for (i, j) in &pairs {
         let (Some(a), Some(b)) = (cur.slides.get(*i), rev.slides.get(*j)) else { continue };
-        let details = slide_details(cur, a, rev, b, &mut media);
+        let details = slide_details(cur, a, rev, b);
         if !details.is_empty() {
             out.push(Change { kind: ChangeKind::Changed, slide: *i, number: i.saturating_add(1), only_in: None, revised: Some(*j), details });
         }
@@ -141,18 +140,10 @@ pub fn diff(cur: &Presentation, rev: &Presentation, by_position: bool) -> Vec<Ch
             });
         }
     }
-    // Each revised slide's open match (the first pair naming it).
-    let mut rev_to_cur: HashMap<usize, usize> = HashMap::new();
-    for p in &pairs {
-        rev_to_cur.entry(p.1).or_insert(p.0);
-    }
-    // After the open slide that matches the nearest matched revised slide before it.
-    let mut at = 0;
     for (j, s) in rev.slides.iter().enumerate() {
-        if let Some(i) = rev_to_cur.get(&j) {
-            at = i + 1;
-        }
         if !rev_matched.contains(&j) {
+            // After the open slide that matches the revised slide before it.
+            let at = (0..j).rev().find_map(|k| pairs.iter().find(|p| p.1 == k).map(|p| p.0 + 1)).unwrap_or(0);
             out.push(Change {
                 kind: ChangeKind::Inserted,
                 slide: at,
@@ -183,34 +174,8 @@ fn shape_label(s: &Shape) -> String {
     if s.name.trim().is_empty() { format!("Shape {}", s.id.0) } else { s.name.clone() }
 }
 
-/// Both decks' media bytes by id, and which picture pairs were already compared: a deck can
-/// show one picture many times, and its bytes are compared once per pair.
-struct Media<'a> {
-    cur: HashMap<MediaId, &'a [u8]>,
-    rev: HashMap<MediaId, &'a [u8]>,
-    same: HashMap<(MediaId, MediaId), bool>,
-}
-
-impl<'a> Media<'a> {
-    fn new(cur: &'a Presentation, rev: &'a Presentation) -> Self {
-        // The first item with an id wins, as in `Presentation::media`.
-        let index = |p: &'a Presentation| {
-            let mut m = HashMap::new();
-            for x in &p.media {
-                m.entry(x.id).or_insert(x.data.as_slice());
-            }
-            m
-        };
-        Media { cur: index(cur), rev: index(rev), same: HashMap::new() }
-    }
-    /// Whether the pictures (by media id, `None` for a shape that is not a picture) differ.
-    fn differ(&mut self, a: Option<MediaId>, b: Option<MediaId>) -> bool {
-        let (ba, bb) = (a.and_then(|x| self.cur.get(&x)), b.and_then(|y| self.rev.get(&y)));
-        match (a, b) {
-            (Some(x), Some(y)) if ba.is_some() && bb.is_some() => !*self.same.entry((x, y)).or_insert_with(|| ba == bb),
-            _ => ba.is_some() || bb.is_some(),
-        }
-    }
+fn media_bytes(p: &Presentation, id: MediaId) -> Option<&[u8]> {
+    p.media(id).map(|m| m.data.as_slice())
 }
 
 /// A shape without its ids (shape and media), for comparing across decks.
@@ -239,7 +204,7 @@ fn turn(ctx: Option<&Ctx>, s: &Shape) -> (f64, bool, bool) {
     drawn_box(ctx, s).map_or((0.0, false, false), |x| (x.rot, x.flip_h, x.flip_v))
 }
 
-fn shape_details(ca: Option<&Ctx>, a: &Shape, cb: Option<&Ctx>, b: &Shape, media: &mut Media, out: &mut Vec<String>) {
+fn shape_details(cp: &Presentation, ca: Option<&Ctx>, a: &Shape, rp: &Presentation, cb: Option<&Ctx>, b: &Shape, out: &mut Vec<String>) {
     let label = shape_label(b);
     let text = |s: &Shape| s.text.as_ref().map(|t| t.text()).unwrap_or_default();
     let mut what = vec![];
@@ -269,11 +234,11 @@ fn shape_details(ca: Option<&Ctx>, a: &Shape, cb: Option<&Ctx>, b: &Shape, media
     if a.fill != b.fill || a.line != b.line || a.style != b.style || a.effects != b.effects {
         what.push("formatting");
     }
-    let pic = |s: &Shape| match &s.kind {
-        ShapeKind::Picture { fill } => Some(fill.media),
+    let pic = |p: &Presentation, s: &Shape| match &s.kind {
+        ShapeKind::Picture { fill } => media_bytes(p, fill.media).map(|b| b.to_vec()),
         _ => None,
     };
-    if media.differ(pic(a), pic(b)) {
+    if pic(cp, a) != pic(rp, b) {
         what.push("picture");
     }
     // Anything the checks above do not cover (alt text, hidden, a link…) is reported too, also
@@ -300,32 +265,21 @@ fn shape_details(ca: Option<&Ctx>, a: &Shape, cb: Option<&Ctx>, b: &Shape, media
     }
 }
 
-fn slide_details(cp: &Presentation, a: &Slide, rp: &Presentation, b: &Slide, media: &mut Media) -> Vec<String> {
+fn slide_details(cp: &Presentation, a: &Slide, rp: &Presentation, b: &Slide) -> Vec<String> {
     let mut out = vec![];
     let mut used: HashSet<usize> = HashSet::new();
     let (ca, cb) = (Ctx::for_slide(cp, a), Ctx::for_slide(rp, b));
-    // The revised shapes by id (first wins) and by name (in order, with a cursor past used ones).
-    let mut by_id: HashMap<ShapeId, usize> = HashMap::new();
-    let mut by_name: HashMap<&str, (Vec<usize>, usize)> = HashMap::new();
-    for (k, x) in b.shapes.iter().enumerate() {
-        by_id.entry(x.id).or_insert(k);
-        if !x.name.is_empty() {
-            by_name.entry(x.name.as_str()).or_default().0.push(k);
-        }
-    }
     for sa in &a.shapes {
-        let k = by_id.get(&sa.id).copied().or_else(|| {
-            let (ks, next) = by_name.get_mut(sa.name.as_str())?;
-            while ks.get(*next).is_some_and(|k| used.contains(k)) {
-                *next += 1;
-            }
-            ks.get(*next).copied()
-        });
+        let k = b
+            .shapes
+            .iter()
+            .position(|x| x.id == sa.id)
+            .or_else(|| b.shapes.iter().enumerate().position(|(k, x)| !used.contains(&k) && x.name == sa.name && !x.name.is_empty()));
         match k {
             Some(k) if !used.contains(&k) => {
                 used.insert(k);
                 if let Some(sb) = b.shapes.get(k) {
-                    shape_details(ca.as_ref(), sa, cb.as_ref(), sb, media, &mut out);
+                    shape_details(cp, ca.as_ref(), sa, rp, cb.as_ref(), sb, &mut out);
                 }
             }
             _ => out.push(format!("{} deleted (only in the deck)", shape_label(sa))),
@@ -380,34 +334,19 @@ pub fn adopt(doc: &mut Presentation, rev: &Presentation, slide: &Slide, replacin
     let mut sl = slide.clone();
     // Media.
     let mut media_map: HashMap<MediaId, MediaId> = HashMap::new();
-    // Both decks' media by id (the first item with an id wins, as in `Presentation::media`),
-    // looked up once per reference instead of searched.
-    let mut rev_at: HashMap<MediaId, usize> = HashMap::new();
-    for (i, m) in rev.media.iter().enumerate() {
-        rev_at.entry(m.id).or_insert(i);
-    }
-    let mut doc_at: HashMap<MediaId, usize> = HashMap::new();
-    for (i, m) in doc.media.iter().enumerate() {
-        doc_at.entry(m.id).or_insert(i);
-    }
     for id in crate::media_refs::slide_media(&sl) {
-        let Some(m) = rev_at.get(&id).and_then(|&i| rev.media.get(i)) else { continue };
-        match doc_at.get(&id).and_then(|&i| doc.media.get(i)) {
+        let Some(m) = rev.media(id) else { continue };
+        match doc.media(id) {
             Some(x) if x.data == m.data => {}
             None => {
                 // Keeps the revision's id, so later ids must start past it.
-                doc_at.insert(id, doc.media.len());
                 doc.media.push(m.clone());
                 doc.next_id = doc.next_id.max(id.0);
             }
             Some(_) => {
-                let before = doc.media.len();
                 let new = doc
                     .add_media(&m.name, &m.content_type, m.data.as_ref().clone())
                     .ok_or_else(|| crate::cmd::bad("review.accept", crate::cmd::NO_ID_SPACE))?;
-                if doc.media.len() > before {
-                    doc_at.entry(new).or_insert(before);
-                }
                 media_map.insert(id, new);
             }
         }
@@ -580,39 +519,6 @@ mod tests {
         assert_eq!(s.doc().unwrap().doc.slides.len(), n, "comparing alone changes nothing");
     }
 
-    #[test]
-    fn many_inserted_slides_and_same_named_pictures_compare_by_index() {
-        use std::sync::Arc;
-
-        use deckcraft_model::style::PictureFill;
-        use deckcraft_model::{Shape, ShapeId, ShapeKind, SlideId, defaults};
-
-        // One slide of 3,000 pictures of one image, all named "Box"; the revision has the same
-        // pictures under other ids (matched by name, in order) and 3,000 slides inserted after it.
-        let mut cur = defaults::new_presentation(None);
-        let img = cur.add_media("a.png", "image/png", vec![7; 4096]).unwrap();
-        let mut rev = cur.clone();
-        let pic = |id: u32| Shape {
-            id: ShapeId(id),
-            name: "Box".into(),
-            xfrm: Some(deckcraft_model::Xfrm::new(10.0, 10.0, 50.0, 50.0)),
-            kind: ShapeKind::Picture { fill: PictureFill { media: img, ..Default::default() } },
-            ..Default::default()
-        };
-        Arc::make_mut(&mut cur.slides[0]).shapes = (0..3000).map(|k| pic(100_000 + k)).collect();
-        Arc::make_mut(&mut rev.slides[0]).shapes = (0..3000).map(|k| pic(200_000 + k)).collect();
-        let mut base = (*rev.slides[0]).clone();
-        base.shapes.clear();
-        for k in 0..3000 {
-            let mut s = base.clone();
-            s.id = SlideId(300_000 + k);
-            rev.slides.push(Arc::new(s));
-        }
-        let changes = super::diff(&cur, &rev, false);
-        assert_eq!(changes.len(), 3000, "only the inserted slides differ");
-        assert!(changes.iter().all(|c| c.kind == super::ChangeKind::Inserted && c.slide == 1));
-    }
-
     /// A deck with one slide: a table whose cell has a picture fill, a picture background and a
     /// transition sound. `tag` starts the bytes of each.
     fn media_deck(tag: &str) -> deckcraft_model::Presentation {

crates/text/src/breaking.rs

@@ -260,12 +260,15 @@ pub(crate) struct Tab {
     align: TabAlign,
 }
 
+/// The paragraph's tab stops in position order (a stop at no finite position is left out), so
+/// [`tab_advance`] finds the next one by binary search instead of a scan per tab.
 pub(crate) fn tabs_of(props: &ParaProps) -> Vec<Tab> {
-    props
+    let mut tabs: Vec<Tab> = props
         .tabs
         .as_ref()
         .map(|t| {
             t.iter()
+                .filter(|s| s.pos.is_finite())
                 .map(|s| Tab {
                     pos: s.pos,
                     align: match s.align.as_str() {
@@ -277,7 +280,9 @@ pub(crate) fn tabs_of(props: &ParaProps) -> Vec<Tab> {
                 })
                 .collect()
         })
-        .unwrap_or_default()
+        .unwrap_or_default();
+    tabs.sort_by(|a, b| a.pos.total_cmp(&b.pos));
+    tabs
 }
 
 /// Width of the text after the tab at cell `i` up to the next tab or line break, and the width of
@@ -301,18 +306,30 @@ pub(crate) fn tab_segment(cells: &[Cell], i: usize) -> (f64, f64) {
 /// (`seg`: its width, and its width before the decimal point) as the stop aligns it but never
 /// moving back, as PowerPoint does; past the last stop, to the next default stop.
 pub(crate) fn tab_advance(x: f64, stops: &[Tab], default_tab: f64, seg: (f64, f64)) -> f64 {
-    for s in stops {
-        if s.pos > x + 0.5 {
-            let to = s.pos - x;
-            return match s.align {
-                TabAlign::Left => to,
-                TabAlign::Right => (to - seg.0).max(0.0),
-                TabAlign::Center => (to - seg.0 / 2.0).max(0.0),
-                TabAlign::Decimal => (to - seg.1).max(0.0),
-            };
-        }
+    // `stops` is in position order (`tabs_of`): the next stop is the first past x.
+    // A NaN `x` (a NaN spacing upstream) skips the lookup and takes the finite default-stop path.
+    if let Some(s) = stops.get(stops.partition_point(|s| s.pos <= x + 0.5)).filter(|_| !x.is_nan()) {
+        let to = s.pos - x;
+        return match s.align {
+            TabAlign::Left => to,
+            TabAlign::Right => (to - seg.0).max(0.0),
+            TabAlign::Center => (to - seg.0 / 2.0).max(0.0),
+            TabAlign::Decimal => (to - seg.1).max(0.0),
+        };
     }
     let d = if default_tab > 1.0 { default_tab } else { 72.0 };
     let next = ((x / d).floor() + 1.0) * d;
     (next - x).max(1.0)
 }
+
+#[cfg(test)]
+mod tab_tests {
+    use super::*;
+
+    #[test]
+    fn a_nan_position_takes_the_finite_default_stop() {
+        let stops = [Tab { pos: 100.0, align: TabAlign::Left }];
+        assert!(tab_advance(f64::NAN, &stops, 72.0, (0.0, 0.0)).is_finite());
+        assert_eq!(tab_advance(10.0, &stops, 72.0, (0.0, 0.0)), 90.0);
+    }
+}

crates/text/src/tests.rs

@@ -1416,6 +1416,16 @@ fn tab_stops_align_the_text_after_them() {
     assert!((l.lines[0].edges[4].0 - x0(&l) - 72.0).abs() < 0.01);
 }
 
+#[test]
+fn many_tabs_over_many_stops_lay_out_by_position() {
+    // 20,000 stops given out of order, and 2,000 tabs: each tab finds the next stop by position.
+    let mut stops: Vec<(f64, &str)> = (1..=20_000).rev().map(|k| (k as f64 * 0.05 + 30.0, "l")).collect();
+    stops.push((f64::NAN, "l"));
+    let text = "a\t".repeat(2_000);
+    let l = tabbed(&text, &stops, 1.0e6);
+    assert!((l.lines[0].edges[2].0 - l.inner.x0 - 30.05).abs() < 0.01, "{:?}", &l.lines[0].edges[..3]);
+}
+
 #[test]
 fn a_tab_past_the_end_moves_to_the_next_line() {
     // PowerPoint: "abcdefghij\tk\tl\tm…" in a narrow box puts the tab that doesn't fit on the next