[repacker] Validate link positions before running the repacker.
diff --git a/src/graph/graph.hh b/src/graph/graph.hh
index b81f869..8a947ab 100644
--- a/src/graph/graph.hh
+++ b/src/graph/graph.hh
@@ -49,6 +49,34 @@
unsigned end = 0;
unsigned priority = 0;
+
+ bool link_positions_valid (unsigned parent_index)
+ {
+ hb_set_t assigned_bytes;
+ for (const auto& l : obj.real_links)
+ {
+ unsigned start = l.position;
+ unsigned end = start + l.width - 1;
+
+ if (unlikely (end >= table_size ()))
+ {
+ DEBUG_MSG (SUBSET_REPACK, nullptr,
+ "Invalid graph. Link position is out of bounds.");
+ return false;
+ }
+
+ if (unlikely (assigned_bytes.intersects (start, end)))
+ {
+ DEBUG_MSG (SUBSET_REPACK, nullptr,
+ "Invalid graph. Found offsets whose positions overlap.");
+ return false;
+ }
+
+ assigned_bytes.add_range (start, end);
+ }
+ return true;
+ }
+
void normalize ()
{
obj.real_links.qsort ();
@@ -299,6 +327,8 @@
vertex_t* v = vertices_.push ();
if (check_success (!vertices_.in_error ()))
v->obj = *objects[i];
+
+ check_success (v->link_positions_valid (i));
if (!removed_nil) continue;
// Fix indices to account for removed nil object.
for (auto& l : v->obj.all_links_writer ()) {
