Fix, cleanup and refactor compute_modifications

1 files changed, 102 insertions, 15 deletions

diff --git a/src/modification.cc b/src/modification.cc
index b5e91c1f..2539ea3a 100644
--- a/src/modification.cc
+++ b/src/modification.cc
@@ -19,6 +19,64 @@ ByteCount change_added_column(const Buffer::Change& change)
 
 }
 
+ByteCoord Modification::added_end() const
+{
+    if (num_added.line)
+        return { new_coord.line + num_added.line, num_added.column };
+    else
+        return { new_coord.line, new_coord.column + num_added.column };
+}
+
+ByteCoord Modification::removed_end() const
+{
+    if (num_removed.line)
+        return { old_coord.line + num_removed.line, num_removed.column };
+    else
+        return { old_coord.line, old_coord.column + num_removed.column };
+}
+
+ByteCoord Modification::get_old_coord(ByteCoord coord) const
+{
+    Modification inverse = { new_coord, old_coord, num_added, num_removed };
+    return inverse.get_new_coord(coord);
+}
+
+ByteCoord Modification::get_new_coord(ByteCoord coord) const
+{
+    if (coord < old_coord)
+        return coord;
+
+    // apply remove
+    if (coord < removed_end())
+        coord = old_coord;
+    else if (coord.line == old_coord.line + num_removed.line)
+    {
+        coord.line = old_coord.line;
+        if (num_removed.line != 0)
+            coord.column += old_coord.column;
+        coord.column -= num_removed.column;
+    }
+    else
+        coord.line -= num_removed.line;
+
+    // apply move
+    coord.line += new_coord.line - old_coord.line;
+    if (coord.line == new_coord.line)
+        coord.column += new_coord.column - old_coord.column;
+
+    // apply add
+    if (coord.line == new_coord.line)
+    {
+        if (num_added.line == 0)
+            coord.column += num_added.column;
+        else
+            coord.column += num_added.column - new_coord.column;
+    }
+    coord.line += num_added.line;
+
+    return coord;
+}
+
 std::vector<Modification> compute_modifications(memoryview<Buffer::Change> changes)
 {
     std::vector<Modification> res;
@@ -45,27 +103,27 @@ std::vector<Modification> compute_modifications(memoryview<Buffer::Change> chang
         {
             const LineCount last_line = modif.new_coord.line + modif.num_added.line;
 
-            ByteCoord num_added = { change.end.line - change.begin.line, 0 };
-
-            modif.num_added.line += num_added.line;
+            modif.num_added.line += change.end.line - change.begin.line;
 
             if (change.begin.line == last_line)
             {
                 if (change.end.line == change.begin.line)
-                    num_added.column = change.end.column - change.begin.column;
+                    modif.num_added.column += change.end.column - change.begin.column;
                 else
-                    num_added.column = change.end.column - modif.num_added.column;
-
-                modif.num_added.column += num_added.column;
+                    modif.num_added.column = change.end.column;
                 kak_assert(modif.num_added.column >= 0);
             }
 
             for (auto it = next; it != res.end(); ++it)
             {
-                if (it->new_coord.line == change.begin.line and it->num_added.line == 0)
-                    it->new_coord.column += num_added.column;
-
-                it->new_coord.line += num_added.line;
+                if (it->new_coord.line == change.begin.line)
+                    it->new_coord.column += change.end.column - change.begin.column;
+                it->new_coord.line += change.end.line - change.begin.line;
+
+#ifdef KAK_DEBUG
+                auto ref_new_coord = (it-1)->get_new_coord(it->old_coord);
+                kak_assert(it->new_coord == ref_new_coord);
+#endif
             }
         }
         else
@@ -83,7 +141,7 @@ std::vector<Modification> compute_modifications(memoryview<Buffer::Change> chang
             for (auto it = next; it != delend; ++it)
             {
                 {
-                    LineCount removed_from_it = (change.begin.line + num_removed.line - it->new_coord.line);
+                    LineCount removed_from_it = change.end.line - it->new_coord.line;
                     modif.num_removed.line += it->num_removed.line - std::min(removed_from_it, it->num_added.line);
                     modif.num_added.line += std::max(0_line, it->num_added.line - removed_from_it);
                 }
@@ -111,12 +169,28 @@ std::vector<Modification> compute_modifications(memoryview<Buffer::Change> chang
 
             for (auto it = next; it != res.end(); ++it)
             {
-                if (it->new_coord.line == change.end.line and it->num_added.line == 0)
-                    it->new_coord.column -= num_removed.column;
-                it->new_coord.line -= num_removed.line;
+                if (it->new_coord.line == change.end.line)
+                    it->new_coord.column += change.begin.column - change.end.column;
+                it->new_coord.line += change.begin.line - change.end.line;
+
+#ifdef KAK_DEBUG
+                auto ref_new_coord = (it-1)->get_new_coord(it->old_coord);
+                kak_assert(it->new_coord == ref_new_coord);
+#endif
             }
         }
     }
+
+#ifdef KAK_DEBUG
+    for (size_t i = 0; i+1 < res.size(); ++i)
+    {
+        auto old_coord = res[i].get_old_coord(res[i+1].new_coord);
+        kak_assert(res[i+1].old_coord == old_coord);
+        auto new_coord = res[i].get_new_coord(res[i+1].old_coord);
+        kak_assert(res[i+1].new_coord == new_coord);
+    }
+#endif
+
     return res;
 }
 
@@ -125,4 +199,17 @@ std::vector<Modification> compute_modifications(const Buffer& buffer, size_t tim
     return compute_modifications(buffer.changes_since(timestamp));
 }
 
+ByteCoord update_pos(memoryview<Modification> modifs, ByteCoord pos)
+{
+    auto modif_it = std::upper_bound(modifs.begin(), modifs.end(), pos,
+                                     [](const ByteCoord& c, const Modification& m)
+                                     { return c < m.old_coord; });
+    if (modif_it != modifs.begin())
+    {
+        auto& prev = *(modif_it-1);
+        return prev.get_new_coord(pos);
+    }
+    return pos;
+}
+
 }