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-rw-r--r--Build/source/libs/harfbuzz/harfbuzz-src/src/hb-repacker.hh737
1 files changed, 581 insertions, 156 deletions
diff --git a/Build/source/libs/harfbuzz/harfbuzz-src/src/hb-repacker.hh b/Build/source/libs/harfbuzz/harfbuzz-src/src/hb-repacker.hh
index b02128b5c4c..26faa56ea85 100644
--- a/Build/source/libs/harfbuzz/harfbuzz-src/src/hb-repacker.hh
+++ b/Build/source/libs/harfbuzz/harfbuzz-src/src/hb-repacker.hh
@@ -33,6 +33,10 @@
#include "hb-serialize.hh"
#include "hb-vector.hh"
+/*
+ * For a detailed writeup on the overflow resolution algorithm see:
+ * docs/repacker.md
+ */
struct graph_t
{
@@ -40,23 +44,58 @@ struct graph_t
{
vertex_t () :
distance (0),
- incoming_edges (0),
+ space (0),
+ parents (),
start (0),
end (0),
priority(0) {}
- void fini () { obj.fini (); }
+ void fini () {
+ obj.fini ();
+ parents.fini ();
+ }
hb_serialize_context_t::object_t obj;
int64_t distance;
- unsigned incoming_edges;
+ int64_t space;
+ hb_vector_t<unsigned> parents;
unsigned start;
unsigned end;
unsigned priority;
bool is_shared () const
{
- return incoming_edges > 1;
+ return parents.length > 1;
+ }
+
+ unsigned incoming_edges () const
+ {
+ return parents.length;
+ }
+
+ void remove_parent (unsigned parent_index)
+ {
+ for (unsigned i = 0; i < parents.length; i++)
+ {
+ if (parents[i] != parent_index) continue;
+ parents.remove (i);
+ break;
+ }
+ }
+
+ void remap_parents (const hb_vector_t<unsigned>& id_map)
+ {
+ for (unsigned i = 0; i < parents.length; i++)
+ parents[i] = id_map[parents[i]];
+ }
+
+ void remap_parent (unsigned old_index, unsigned new_index)
+ {
+ for (unsigned i = 0; i < parents.length; i++)
+ {
+ if (parents[i] == old_index)
+ parents[i] = new_index;
+ }
}
bool is_leaf () const
@@ -77,7 +116,7 @@ struct graph_t
int64_t modified_distance =
hb_min (hb_max(distance + distance_modifier (), 0), 0x7FFFFFFFFF);
- return (modified_distance << 24) | (0x00FFFFFF & order);
+ return (modified_distance << 22) | (0x003FFFFF & order);
}
int64_t distance_modifier () const
@@ -91,34 +130,7 @@ struct graph_t
struct overflow_record_t
{
unsigned parent;
- const hb_serialize_context_t::object_t::link_t* link;
- };
-
- struct clone_buffer_t
- {
- clone_buffer_t () : head (nullptr), tail (nullptr) {}
-
- bool copy (const hb_serialize_context_t::object_t& object)
- {
- fini ();
- unsigned size = object.tail - object.head;
- head = (char*) hb_malloc (size);
- if (!head) return false;
-
- memcpy (head, object.head, size);
- tail = head + size;
- return true;
- }
-
- char* head;
- char* tail;
-
- void fini ()
- {
- if (!head) return;
- hb_free (head);
- head = nullptr;
- }
+ unsigned child;
};
/*
@@ -129,11 +141,12 @@ struct graph_t
* serializer
*/
graph_t (const hb_vector_t<hb_serialize_context_t::object_t *>& objects)
- : edge_count_invalid (true),
+ : parents_invalid (true),
distance_invalid (true),
positions_invalid (true),
successful (true)
{
+ num_roots_for_space_.push (1);
bool removed_nil = false;
for (unsigned i = 0; i < objects.length; i++)
{
@@ -160,12 +173,13 @@ struct graph_t
~graph_t ()
{
vertices_.fini_deep ();
- clone_buffers_.fini_deep ();
}
bool in_error () const
{
- return !successful || vertices_.in_error () || clone_buffers_.in_error ();
+ return !successful ||
+ vertices_.in_error () ||
+ num_roots_for_space_.in_error ();
}
const vertex_t& root () const
@@ -226,12 +240,13 @@ struct graph_t
hb_vector_t<unsigned> queue;
hb_vector_t<vertex_t> sorted_graph;
+ if (unlikely (!check_success (sorted_graph.resize (vertices_.length)))) return;
hb_vector_t<unsigned> id_map;
if (unlikely (!check_success (id_map.resize (vertices_.length)))) return;
hb_vector_t<unsigned> removed_edges;
if (unlikely (!check_success (removed_edges.resize (vertices_.length)))) return;
- update_incoming_edge_count ();
+ update_parents ();
queue.push (root_idx ());
int new_id = vertices_.length - 1;
@@ -242,12 +257,12 @@ struct graph_t
queue.remove (0);
vertex_t& next = vertices_[next_id];
- sorted_graph.push (next);
+ sorted_graph[new_id] = next;
id_map[next_id] = new_id--;
for (const auto& link : next.obj.links) {
removed_edges[link.objidx]++;
- if (!(vertices_[link.objidx].incoming_edges - removed_edges[link.objidx]))
+ if (!(vertices_[link.objidx].incoming_edges () - removed_edges[link.objidx]))
queue.push (link.objidx);
}
}
@@ -255,14 +270,11 @@ struct graph_t
check_success (!queue.in_error ());
check_success (!sorted_graph.in_error ());
if (!check_success (new_id == -1))
- DEBUG_MSG (SUBSET_REPACK, nullptr, "Graph is not fully connected.");
-
- remap_obj_indices (id_map, &sorted_graph);
+ print_orphaned_nodes ();
- sorted_graph.as_array ().reverse ();
+ remap_all_obj_indices (id_map, &sorted_graph);
- vertices_.fini_deep ();
- vertices_ = sorted_graph;
+ hb_swap (vertices_, sorted_graph);
sorted_graph.fini_deep ();
}
@@ -283,12 +295,13 @@ struct graph_t
hb_priority_queue_t queue;
hb_vector_t<vertex_t> sorted_graph;
+ if (unlikely (!check_success (sorted_graph.resize (vertices_.length)))) return;
hb_vector_t<unsigned> id_map;
if (unlikely (!check_success (id_map.resize (vertices_.length)))) return;
hb_vector_t<unsigned> removed_edges;
if (unlikely (!check_success (removed_edges.resize (vertices_.length)))) return;
- update_incoming_edge_count ();
+ update_parents ();
queue.insert (root ().modified_distance (0), root_idx ());
int new_id = root_idx ();
@@ -298,12 +311,12 @@ struct graph_t
unsigned next_id = queue.pop_minimum().second;
vertex_t& next = vertices_[next_id];
- sorted_graph.push (next);
+ sorted_graph[new_id] = next;
id_map[next_id] = new_id--;
for (const auto& link : next.obj.links) {
removed_edges[link.objidx]++;
- if (!(vertices_[link.objidx].incoming_edges - removed_edges[link.objidx]))
+ if (!(vertices_[link.objidx].incoming_edges () - removed_edges[link.objidx]))
// Add the order that the links were encountered to the priority.
// This ensures that ties between priorities objects are broken in a consistent
// way. More specifically this is set up so that if a set of objects have the same
@@ -317,66 +330,264 @@ struct graph_t
check_success (!queue.in_error ());
check_success (!sorted_graph.in_error ());
if (!check_success (new_id == -1))
- DEBUG_MSG (SUBSET_REPACK, nullptr, "Graph is not fully connected.");
-
- remap_obj_indices (id_map, &sorted_graph);
+ print_orphaned_nodes ();
- sorted_graph.as_array ().reverse ();
+ remap_all_obj_indices (id_map, &sorted_graph);
- vertices_.fini_deep ();
- vertices_ = sorted_graph;
+ hb_swap (vertices_, sorted_graph);
sorted_graph.fini_deep ();
}
/*
- * Creates a copy of child and re-assigns the link from
- * parent to the clone. The copy is a shallow copy, objects
- * linked from child are not duplicated.
+ * Assign unique space numbers to each connected subgraph of 32 bit offset(s).
*/
- void duplicate (unsigned parent_idx, unsigned child_idx)
+ bool assign_32bit_spaces ()
{
- DEBUG_MSG (SUBSET_REPACK, nullptr, " Duplicating %d => %d",
- parent_idx, child_idx);
+ unsigned root_index = root_idx ();
+ hb_set_t visited;
+ hb_set_t roots;
+ for (unsigned i = 0; i <= root_index; i++)
+ {
+ for (auto& l : vertices_[i].obj.links)
+ {
+ if (l.width == 4 && !l.is_signed)
+ {
+ roots.add (l.objidx);
+ find_subgraph (l.objidx, visited);
+ }
+ }
+ }
+
+ // Mark everything not in the subgraphs of 32 bit roots as visited.
+ // This prevents 32 bit subgraphs from being connected via nodes not in the 32 bit subgraphs.
+ visited.invert ();
+
+ if (!roots) return false;
+
+ while (roots)
+ {
+ unsigned next = HB_SET_VALUE_INVALID;
+ if (!roots.next (&next)) break;
+
+ hb_set_t connected_roots;
+ find_connected_nodes (next, roots, visited, connected_roots);
+ isolate_subgraph (connected_roots);
+
+ unsigned next_space = this->next_space ();
+ num_roots_for_space_.push (0);
+ for (unsigned root : connected_roots)
+ {
+ DEBUG_MSG (SUBSET_REPACK, nullptr, "Subgraph %u gets space %u", root, next_space);
+ vertices_[root].space = next_space;
+ num_roots_for_space_[next_space] = num_roots_for_space_[next_space] + 1;
+ distance_invalid = true;
+ positions_invalid = true;
+ }
+
+ // TODO(grieger): special case for GSUB/GPOS use extension promotions to move 16 bit space
+ // into the 32 bit space as needed, instead of using isolation.
+ }
+
+ return true;
+ }
+
+ /*
+ * Isolates the subgraph of nodes reachable from root. Any links to nodes in the subgraph
+ * that originate from outside of the subgraph will be removed by duplicating the linked to
+ * object.
+ *
+ * Indices stored in roots will be updated if any of the roots are duplicated to new indices.
+ */
+ bool isolate_subgraph (hb_set_t& roots)
+ {
+ update_parents ();
+ hb_hashmap_t<unsigned, unsigned> subgraph;
+
+ // incoming edges to root_idx should be all 32 bit in length so we don't need to de-dup these
+ // set the subgraph incoming edge count to match all of root_idx's incoming edges
+ hb_set_t parents;
+ for (unsigned root_idx : roots)
+ {
+ subgraph.set (root_idx, wide_parents (root_idx, parents));
+ find_subgraph (root_idx, subgraph);
+ }
+
+ unsigned original_root_idx = root_idx ();
+ hb_hashmap_t<unsigned, unsigned> index_map;
+ bool made_changes = false;
+ for (auto entry : subgraph.iter ())
+ {
+ const auto& node = vertices_[entry.first];
+ unsigned subgraph_incoming_edges = entry.second;
+
+ if (subgraph_incoming_edges < node.incoming_edges ())
+ {
+ // Only de-dup objects with incoming links from outside the subgraph.
+ made_changes = true;
+ duplicate_subgraph (entry.first, index_map);
+ }
+ }
+
+ if (!made_changes)
+ return false;
+ if (original_root_idx != root_idx ()
+ && parents.has (original_root_idx))
+ {
+ // If the root idx has changed since parents was determined, update root idx in parents
+ parents.add (root_idx ());
+ parents.del (original_root_idx);
+ }
+
+ auto new_subgraph =
+ + subgraph.keys ()
+ | hb_map([&] (unsigned node_idx) {
+ if (index_map.has (node_idx)) return index_map[node_idx];
+ return node_idx;
+ })
+ ;
+
+ remap_obj_indices (index_map, new_subgraph);
+ remap_obj_indices (index_map, parents.iter (), true);
+
+ // Update roots set with new indices as needed.
+ unsigned next = HB_SET_VALUE_INVALID;
+ while (roots.next (&next))
+ {
+ if (index_map.has (next))
+ {
+ roots.del (next);
+ roots.add (index_map[next]);
+ }
+ }
+
+ return true;
+ }
+
+ void find_subgraph (unsigned node_idx, hb_hashmap_t<unsigned, unsigned>& subgraph)
+ {
+ for (const auto& link : vertices_[node_idx].obj.links)
+ {
+ if (subgraph.has (link.objidx))
+ {
+ subgraph.set (link.objidx, subgraph[link.objidx] + 1);
+ continue;
+ }
+ subgraph.set (link.objidx, 1);
+ find_subgraph (link.objidx, subgraph);
+ }
+ }
+
+ void find_subgraph (unsigned node_idx, hb_set_t& subgraph)
+ {
+ if (subgraph.has (node_idx)) return;
+ subgraph.add (node_idx);
+ for (const auto& link : vertices_[node_idx].obj.links)
+ find_subgraph (link.objidx, subgraph);
+ }
+
+ /*
+ * duplicates all nodes in the subgraph reachable from node_idx. Does not re-assign
+ * links. index_map is updated with mappings from old id to new id. If a duplication has already
+ * been performed for a given index, then it will be skipped.
+ */
+ void duplicate_subgraph (unsigned node_idx, hb_hashmap_t<unsigned, unsigned>& index_map)
+ {
+ if (index_map.has (node_idx))
+ return;
+
+ index_map.set (node_idx, duplicate (node_idx));
+ for (const auto& l : object (node_idx).links) {
+ duplicate_subgraph (l.objidx, index_map);
+ }
+ }
+
+ /*
+ * Creates a copy of node_idx and returns it's new index.
+ */
+ unsigned duplicate (unsigned node_idx)
+ {
positions_invalid = true;
+ distance_invalid = true;
auto* clone = vertices_.push ();
- auto& child = vertices_[child_idx];
- clone_buffer_t* buffer = clone_buffers_.push ();
- if (vertices_.in_error ()
- || clone_buffers_.in_error ()
- || !check_success (buffer->copy (child.obj))) {
- return;
+ auto& child = vertices_[node_idx];
+ if (vertices_.in_error ()) {
+ return -1;
}
- clone->obj.head = buffer->head;
- clone->obj.tail = buffer->tail;
+ clone->obj.head = child.obj.head;
+ clone->obj.tail = child.obj.tail;
clone->distance = child.distance;
+ clone->space = child.space;
+ clone->parents.reset ();
+ unsigned clone_idx = vertices_.length - 2;
for (const auto& l : child.obj.links)
+ {
clone->obj.links.push (l);
+ vertices_[l.objidx].parents.push (clone_idx);
+ }
check_success (!clone->obj.links.in_error ());
+ // The last object is the root of the graph, so swap back the root to the end.
+ // The root's obj idx does change, however since it's root nothing else refers to it.
+ // all other obj idx's will be unaffected.
+ vertex_t root = vertices_[vertices_.length - 2];
+ vertices_[clone_idx] = *clone;
+ vertices_[vertices_.length - 1] = root;
+
+ // Since the root moved, update the parents arrays of all children on the root.
+ for (const auto& l : root.obj.links)
+ vertices_[l.objidx].remap_parent (root_idx () - 1, root_idx ());
+
+ return clone_idx;
+ }
+
+ /*
+ * Creates a copy of child and re-assigns the link from
+ * parent to the clone. The copy is a shallow copy, objects
+ * linked from child are not duplicated.
+ */
+ bool duplicate (unsigned parent_idx, unsigned child_idx)
+ {
+ update_parents ();
+
+ unsigned links_to_child = 0;
+ for (const auto& l : vertices_[parent_idx].obj.links)
+ {
+ if (l.objidx == child_idx) links_to_child++;
+ }
+
+ if (vertices_[child_idx].incoming_edges () <= links_to_child)
+ {
+ // Can't duplicate this node, doing so would orphan the original one as all remaining links
+ // to child are from parent.
+ DEBUG_MSG (SUBSET_REPACK, nullptr, " Not duplicating %d => %d",
+ parent_idx, child_idx);
+ return false;
+ }
+
+ DEBUG_MSG (SUBSET_REPACK, nullptr, " Duplicating %d => %d",
+ parent_idx, child_idx);
+
+ unsigned clone_idx = duplicate (child_idx);
+ if (clone_idx == (unsigned) -1) return false;
+ // duplicate shifts the root node idx, so if parent_idx was root update it.
+ if (parent_idx == clone_idx) parent_idx++;
+
auto& parent = vertices_[parent_idx];
- unsigned clone_idx = vertices_.length - 2;
for (unsigned i = 0; i < parent.obj.links.length; i++)
{
auto& l = parent.obj.links[i];
- if (l.objidx == child_idx)
- {
- l.objidx = clone_idx;
- clone->incoming_edges++;
- child.incoming_edges--;
- }
+ if (l.objidx != child_idx)
+ continue;
+
+ reassign_link (l, parent_idx, clone_idx);
}
- // The last object is the root of the graph, so swap back the root to the end.
- // The root's obj idx does change, however since it's root nothing else refers to it.
- // all other obj idx's will be unaffected.
- vertex_t root = vertices_[vertices_.length - 2];
- vertices_[vertices_.length - 2] = *clone;
- vertices_[vertices_.length - 1] = root;
+ return true;
}
/*
@@ -414,7 +625,7 @@ struct graph_t
overflow_record_t r;
r.parent = parent_idx;
- r.link = &link;
+ r.child = link.objidx;
overflows->push (r);
}
}
@@ -423,48 +634,134 @@ struct graph_t
return overflows->length;
}
+ void print_orphaned_nodes ()
+ {
+ if (!DEBUG_ENABLED(SUBSET_REPACK)) return;
+
+ DEBUG_MSG (SUBSET_REPACK, nullptr, "Graph is not fully connected.");
+ parents_invalid = true;
+ update_parents();
+
+ for (unsigned i = 0; i < root_idx (); i++)
+ {
+ const auto& v = vertices_[i];
+ if (!v.parents)
+ DEBUG_MSG (SUBSET_REPACK, nullptr, "Node %u is orphaned.", i);
+ }
+ }
+
void print_overflows (const hb_vector_t<overflow_record_t>& overflows)
{
if (!DEBUG_ENABLED(SUBSET_REPACK)) return;
- update_incoming_edge_count ();
+ update_parents ();
for (const auto& o : overflows)
{
- const auto& child = vertices_[o.link->objidx];
- DEBUG_MSG (SUBSET_REPACK, nullptr, " overflow from %d => %d (%d incoming , %d outgoing)",
+ const auto& parent = vertices_[o.parent];
+ const auto& child = vertices_[o.child];
+ DEBUG_MSG (SUBSET_REPACK, nullptr,
+ " overflow from "
+ "%4d (%4d in, %4d out, space %2d) => "
+ "%4d (%4d in, %4d out, space %2d)",
o.parent,
- o.link->objidx,
- child.incoming_edges,
- child.obj.links.length);
+ parent.incoming_edges (),
+ parent.obj.links.length,
+ space_for (o.parent),
+ o.child,
+ child.incoming_edges (),
+ child.obj.links.length,
+ space_for (o.child));
}
}
+ unsigned num_roots_for_space (unsigned space) const
+ {
+ return num_roots_for_space_[space];
+ }
+
+ unsigned next_space () const
+ {
+ return num_roots_for_space_.length;
+ }
+
+ void move_to_new_space (unsigned index)
+ {
+ auto& node = vertices_[index];
+ num_roots_for_space_.push (1);
+ num_roots_for_space_[node.space] = num_roots_for_space_[node.space] - 1;
+ node.space = num_roots_for_space_.length - 1;
+ }
+
+ unsigned space_for (unsigned index, unsigned* root = nullptr) const
+ {
+ const auto& node = vertices_[index];
+ if (node.space)
+ {
+ if (root != nullptr)
+ *root = index;
+ return node.space;
+ }
+
+ if (!node.parents)
+ {
+ if (root)
+ *root = index;
+ return 0;
+ }
+
+ return space_for (node.parents[0], root);
+ }
+
void err_other_error () { this->successful = false; }
private:
+ /*
+ * Returns the numbers of incoming edges that are 32bits wide.
+ */
+ unsigned wide_parents (unsigned node_idx, hb_set_t& parents) const
+ {
+ unsigned count = 0;
+ hb_set_t visited;
+ for (unsigned p : vertices_[node_idx].parents)
+ {
+ if (visited.has (p)) continue;
+ visited.add (p);
+
+ for (const auto& l : vertices_[p].obj.links)
+ {
+ if (l.objidx == node_idx && l.width == 4 && !l.is_signed)
+ {
+ count++;
+ parents.add (p);
+ }
+ }
+ }
+ return count;
+ }
+
bool check_success (bool success)
{ return this->successful && (success || (err_other_error (), false)); }
/*
* Creates a map from objid to # of incoming edges.
*/
- void update_incoming_edge_count ()
+ void update_parents ()
{
- if (!edge_count_invalid) return;
+ if (!parents_invalid) return;
for (unsigned i = 0; i < vertices_.length; i++)
- vertices_[i].incoming_edges = 0;
+ vertices_[i].parents.reset ();
- for (const vertex_t& v : vertices_)
+ for (unsigned p = 0; p < vertices_.length; p++)
{
- for (auto& l : v.obj.links)
+ for (auto& l : vertices_[p].obj.links)
{
- vertices_[l.objidx].incoming_edges++;
+ vertices_[l.objidx].parents.push (p);
}
}
- edge_count_invalid = false;
+ parents_invalid = false;
}
/*
@@ -515,23 +812,25 @@ struct graph_t
hb_priority_queue_t queue;
queue.insert (0, vertices_.length - 1);
- hb_set_t visited;
+ hb_vector_t<bool> visited;
+ visited.resize (vertices_.length);
while (!queue.in_error () && !queue.is_empty ())
{
unsigned next_idx = queue.pop_minimum ().second;
- if (visited.has (next_idx)) continue;
+ if (visited[next_idx]) continue;
const auto& next = vertices_[next_idx];
int64_t next_distance = vertices_[next_idx].distance;
- visited.add (next_idx);
+ visited[next_idx] = true;
for (const auto& link : next.obj.links)
{
- if (visited.has (link.objidx)) continue;
+ if (visited[link.objidx]) continue;
const auto& child = vertices_[link.objidx].obj;
- int64_t child_weight = child.tail - child.head +
- ((int64_t) 1 << (link.width * 8));
+ unsigned link_width = link.width ? link.width : 4; // treat virtual offsets as 32 bits wide
+ int64_t child_weight = (child.tail - child.head) +
+ ((int64_t) 1 << (link_width * 8)) * (vertices_[link.objidx].space + 1);
int64_t child_distance = next_distance + child_weight;
if (child_distance < vertices_[link.objidx].distance)
@@ -545,7 +844,7 @@ struct graph_t
check_success (!queue.in_error ());
if (!check_success (queue.is_empty ()))
{
- DEBUG_MSG (SUBSET_REPACK, nullptr, "Graph is not fully connected.");
+ print_orphaned_nodes ();
return;
}
@@ -576,6 +875,10 @@ struct graph_t
bool is_valid_offset (int64_t offset,
const hb_serialize_context_t::object_t::link_t& link) const
{
+ if (unlikely (!link.width))
+ // Virtual links can't overflow.
+ return link.is_signed || offset >= 0;
+
if (link.is_signed)
{
if (link.width == 4)
@@ -595,13 +898,50 @@ struct graph_t
}
/*
+ * Updates a link in the graph to point to a different object. Corrects the
+ * parents vector on the previous and new child nodes.
+ */
+ void reassign_link (hb_serialize_context_t::object_t::link_t& link,
+ unsigned parent_idx,
+ unsigned new_idx)
+ {
+ unsigned old_idx = link.objidx;
+ link.objidx = new_idx;
+ vertices_[old_idx].remove_parent (parent_idx);
+ vertices_[new_idx].parents.push (parent_idx);
+ }
+
+ /*
+ * Updates all objidx's in all links using the provided mapping. Corrects incoming edge counts.
+ */
+ template<typename Iterator, hb_requires (hb_is_iterator (Iterator))>
+ void remap_obj_indices (const hb_hashmap_t<unsigned, unsigned>& id_map,
+ Iterator subgraph,
+ bool only_wide = false)
+ {
+ if (!id_map) return;
+ for (unsigned i : subgraph)
+ {
+ for (unsigned j = 0; j < vertices_[i].obj.links.length; j++)
+ {
+ auto& link = vertices_[i].obj.links[j];
+ if (!id_map.has (link.objidx)) continue;
+ if (only_wide && !(link.width == 4 && !link.is_signed)) continue;
+
+ reassign_link (link, i, id_map[link.objidx]);
+ }
+ }
+ }
+
+ /*
* Updates all objidx's in all links using the provided mapping.
*/
- void remap_obj_indices (const hb_vector_t<unsigned>& id_map,
- hb_vector_t<vertex_t>* sorted_graph) const
+ void remap_all_obj_indices (const hb_vector_t<unsigned>& id_map,
+ hb_vector_t<vertex_t>* sorted_graph) const
{
for (unsigned i = 0; i < sorted_graph->length; i++)
{
+ (*sorted_graph)[i].remap_parents (id_map);
for (unsigned j = 0; j < (*sorted_graph)[i].obj.links.length; j++)
{
auto& link = (*sorted_graph)[i].obj.links[j];
@@ -631,6 +971,9 @@ struct graph_t
{
switch (link.width)
{
+ case 0:
+ // Virtual links aren't serialized.
+ return;
case 4:
if (link.is_signed)
{
@@ -656,17 +999,120 @@ struct graph_t
}
}
+ /*
+ * Finds all nodes in targets that are reachable from start_idx, nodes in visited will be skipped.
+ * For this search the graph is treated as being undirected.
+ *
+ * Connected targets will be added to connected and removed from targets. All visited nodes
+ * will be added to visited.
+ */
+ void find_connected_nodes (unsigned start_idx,
+ hb_set_t& targets,
+ hb_set_t& visited,
+ hb_set_t& connected)
+ {
+ if (visited.has (start_idx)) return;
+ visited.add (start_idx);
+
+ if (targets.has (start_idx))
+ {
+ targets.del (start_idx);
+ connected.add (start_idx);
+ }
+
+ const auto& v = vertices_[start_idx];
+
+ // Graph is treated as undirected so search children and parents of start_idx
+ for (const auto& l : v.obj.links)
+ find_connected_nodes (l.objidx, targets, visited, connected);
+
+ for (unsigned p : v.parents)
+ find_connected_nodes (p, targets, visited, connected);
+ }
+
public:
// TODO(garretrieger): make private, will need to move most of offset overflow code into graph.
hb_vector_t<vertex_t> vertices_;
private:
- hb_vector_t<clone_buffer_t> clone_buffers_;
- bool edge_count_invalid;
+ bool parents_invalid;
bool distance_invalid;
bool positions_invalid;
bool successful;
+ hb_vector_t<unsigned> num_roots_for_space_;
};
+static bool _try_isolating_subgraphs (const hb_vector_t<graph_t::overflow_record_t>& overflows,
+ graph_t& sorted_graph)
+{
+ for (int i = overflows.length - 1; i >= 0; i--)
+ {
+ const graph_t::overflow_record_t& r = overflows[i];
+ unsigned root = 0;
+ unsigned space = sorted_graph.space_for (r.parent, &root);
+ if (!space) continue;
+ if (sorted_graph.num_roots_for_space (space) <= 1) continue;
+
+ DEBUG_MSG (SUBSET_REPACK, nullptr, "Overflow in space %d moving subgraph %d to space %d.",
+ space,
+ root,
+ sorted_graph.next_space ());
+
+ hb_set_t roots;
+ roots.add (root);
+ sorted_graph.isolate_subgraph (roots);
+ for (unsigned new_root : roots)
+ sorted_graph.move_to_new_space (new_root);
+ return true;
+ }
+ return false;
+}
+
+static bool _process_overflows (const hb_vector_t<graph_t::overflow_record_t>& overflows,
+ hb_set_t& priority_bumped_parents,
+ graph_t& sorted_graph)
+{
+ bool resolution_attempted = false;
+
+ // Try resolving the furthest overflows first.
+ for (int i = overflows.length - 1; i >= 0; i--)
+ {
+ const graph_t::overflow_record_t& r = overflows[i];
+ const auto& child = sorted_graph.vertices_[r.child];
+ if (child.is_shared ())
+ {
+ // The child object is shared, we may be able to eliminate the overflow
+ // by duplicating it.
+ if (!sorted_graph.duplicate (r.parent, r.child)) continue;
+ return true;
+ }
+
+ if (child.is_leaf () && !priority_bumped_parents.has (r.parent))
+ {
+ // This object is too far from it's parent, attempt to move it closer.
+ //
+ // TODO(garretrieger): initially limiting this to leaf's since they can be
+ // moved closer with fewer consequences. However, this can
+ // likely can be used for non-leafs as well.
+ // TODO(garretrieger): add a maximum priority, don't try to raise past this.
+ // TODO(garretrieger): also try lowering priority of the parent. Make it
+ // get placed further up in the ordering, closer to it's children.
+ // this is probably preferable if the total size of the parent object
+ // is < then the total size of the children (and the parent can be moved).
+ // Since in that case moving the parent will cause a smaller increase in
+ // the length of other offsets.
+ sorted_graph.raise_childrens_priority (r.parent);
+ priority_bumped_parents.add (r.parent);
+ resolution_attempted = true;
+ continue;
+ }
+
+ // TODO(garretrieger): add additional offset resolution strategies
+ // - Promotion to extension lookups.
+ // - Table splitting.
+ }
+
+ return resolution_attempted;
+}
/*
* Attempts to modify the topological sorting of the provided object graph to
@@ -677,10 +1123,15 @@ struct graph_t
* If necessary the structure of the graph may be modified in ways that do not
* affect the functionality of the graph. For example shared objects may be
* duplicated.
+ *
+ * For a detailed writeup describing how the algorithm operates see:
+ * docs/repacker.md
*/
inline void
hb_resolve_overflows (const hb_vector_t<hb_serialize_context_t::object_t *>& packed,
- hb_serialize_context_t* c) {
+ hb_tag_t table_tag,
+ hb_serialize_context_t* c,
+ unsigned max_rounds = 10) {
// Kahn sort is ~twice as fast as shortest distance sort and works for many fonts
// so try it first to save time.
graph_t sorted_graph (packed);
@@ -693,68 +1144,36 @@ hb_resolve_overflows (const hb_vector_t<hb_serialize_context_t::object_t *>& pac
sorted_graph.sort_shortest_distance ();
+ if ((table_tag == HB_OT_TAG_GPOS
+ || table_tag == HB_OT_TAG_GSUB)
+ && sorted_graph.will_overflow ())
+ {
+ DEBUG_MSG (SUBSET_REPACK, nullptr, "Assigning spaces to 32 bit subgraphs.");
+ if (sorted_graph.assign_32bit_spaces ())
+ sorted_graph.sort_shortest_distance ();
+ }
+
unsigned round = 0;
hb_vector_t<graph_t::overflow_record_t> overflows;
// TODO(garretrieger): select a good limit for max rounds.
while (!sorted_graph.in_error ()
&& sorted_graph.will_overflow (&overflows)
- && round++ < 10) {
- DEBUG_MSG (SUBSET_REPACK, nullptr, "=== Over flow resolution round %d ===", round);
+ && round++ < max_rounds) {
+ DEBUG_MSG (SUBSET_REPACK, nullptr, "=== Overflow resolution round %d ===", round);
sorted_graph.print_overflows (overflows);
- bool resolution_attempted = false;
hb_set_t priority_bumped_parents;
- // Try resolving the furthest overflows first.
- for (int i = overflows.length - 1; i >= 0; i--)
+
+ if (!_try_isolating_subgraphs (overflows, sorted_graph))
{
- const graph_t::overflow_record_t& r = overflows[i];
- const auto& child = sorted_graph.vertices_[r.link->objidx];
- if (child.is_shared ())
+ if (!_process_overflows (overflows, priority_bumped_parents, sorted_graph))
{
- // The child object is shared, we may be able to eliminate the overflow
- // by duplicating it.
- sorted_graph.duplicate (r.parent, r.link->objidx);
- resolution_attempted = true;
-
- // Stop processing overflows for this round so that object order can be
- // updated to account for the newly added object.
+ DEBUG_MSG (SUBSET_REPACK, nullptr, "No resolution available :(");
break;
}
-
- if (child.is_leaf () && !priority_bumped_parents.has (r.parent))
- {
- // This object is too far from it's parent, attempt to move it closer.
- //
- // TODO(garretrieger): initially limiting this to leaf's since they can be
- // moved closer with fewer consequences. However, this can
- // likely can be used for non-leafs as well.
- // TODO(garretrieger): add a maximum priority, don't try to raise past this.
- // TODO(garretrieger): also try lowering priority of the parent. Make it
- // get placed further up in the ordering, closer to it's children.
- // this is probably preferable if the total size of the parent object
- // is < then the total size of the children (and the parent can be moved).
- // Since in that case moving the parent will cause a smaller increase in
- // the length of other offsets.
- sorted_graph.raise_childrens_priority (r.parent);
- priority_bumped_parents.add (r.parent);
- resolution_attempted = true;
- continue;
- }
-
- // TODO(garretrieger): add additional offset resolution strategies
- // - Promotion to extension lookups.
- // - Table splitting.
- }
-
- if (resolution_attempted)
- {
- sorted_graph.sort_shortest_distance ();
- continue;
}
- DEBUG_MSG (SUBSET_REPACK, nullptr, "No resolution available :(");
- c->err (HB_SERIALIZE_ERROR_OFFSET_OVERFLOW);
- return;
+ sorted_graph.sort_shortest_distance ();
}
if (sorted_graph.in_error ())
@@ -762,8 +1181,14 @@ hb_resolve_overflows (const hb_vector_t<hb_serialize_context_t::object_t *>& pac
c->err (HB_SERIALIZE_ERROR_OTHER);
return;
}
+
+ if (sorted_graph.will_overflow ())
+ {
+ c->err (HB_SERIALIZE_ERROR_OFFSET_OVERFLOW);
+ DEBUG_MSG (SUBSET_REPACK, nullptr, "Offset overflow resolution failed.");
+ return;
+ }
sorted_graph.serialize (c);
}
-
#endif /* HB_REPACKER_HH */