| /* |
| * Copyright © 2022 Google, Inc. |
| * |
| * This is part of HarfBuzz, a text shaping library. |
| * |
| * Permission is hereby granted, without written agreement and without |
| * license or royalty fees, to use, copy, modify, and distribute this |
| * software and its documentation for any purpose, provided that the |
| * above copyright notice and the following two paragraphs appear in |
| * all copies of this software. |
| * |
| * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR |
| * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES |
| * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN |
| * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH |
| * DAMAGE. |
| * |
| * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, |
| * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND |
| * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS |
| * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO |
| * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. |
| * |
| * Google Author(s): Garret Rieger |
| */ |
| |
| #include "../hb-set.hh" |
| #include "../hb-priority-queue.hh" |
| #include "../hb-serialize.hh" |
| |
| #ifndef GRAPH_GRAPH_HH |
| #define GRAPH_GRAPH_HH |
| |
| namespace graph { |
| |
| /** |
| * Represents a serialized table in the form of a graph. |
| * Provides methods for modifying and reordering the graph. |
| */ |
| struct graph_t |
| { |
| struct vertex_t |
| { |
| hb_serialize_context_t::object_t obj; |
| int64_t distance = 0 ; |
| unsigned space = 0 ; |
| unsigned start = 0; |
| unsigned end = 0; |
| unsigned priority = 0; |
| private: |
| unsigned incoming_edges_ = 0; |
| unsigned single_parent = (unsigned) -1; |
| hb_hashmap_t<unsigned, unsigned> parents; |
| public: |
| |
| auto parents_iter () const HB_AUTO_RETURN |
| ( |
| hb_concat ( |
| hb_iter (&single_parent, single_parent != (unsigned) -1), |
| parents.keys_ref () |
| ) |
| ) |
| |
| bool in_error () const |
| { |
| return parents.in_error (); |
| } |
| |
| bool link_positions_valid (unsigned num_objects, bool removed_nil) |
| { |
| hb_set_t assigned_bytes; |
| for (const auto& l : obj.real_links) |
| { |
| if (l.objidx >= num_objects |
| || (removed_nil && !l.objidx)) |
| { |
| DEBUG_MSG (SUBSET_REPACK, nullptr, |
| "Invalid graph. Invalid object index."); |
| return false; |
| } |
| |
| unsigned start = l.position; |
| unsigned end = start + l.width - 1; |
| |
| if (unlikely (l.width < 2 || l.width > 4)) |
| { |
| DEBUG_MSG (SUBSET_REPACK, nullptr, |
| "Invalid graph. Invalid link width."); |
| return false; |
| } |
| |
| 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 !assigned_bytes.in_error (); |
| } |
| |
| void normalize () |
| { |
| obj.real_links.qsort (); |
| for (auto& l : obj.real_links) |
| { |
| for (unsigned i = 0; i < l.width; i++) |
| { |
| obj.head[l.position + i] = 0; |
| } |
| } |
| } |
| |
| bool equals (const vertex_t& other, |
| const graph_t& graph, |
| const graph_t& other_graph, |
| unsigned depth) const |
| { |
| if (!(as_bytes () == other.as_bytes ())) |
| { |
| DEBUG_MSG (SUBSET_REPACK, nullptr, |
| "vertex [%lu] bytes != [%lu] bytes, depth = %u", |
| (unsigned long) table_size (), |
| (unsigned long) other.table_size (), |
| depth); |
| |
| auto a = as_bytes (); |
| auto b = other.as_bytes (); |
| while (a || b) |
| { |
| DEBUG_MSG (SUBSET_REPACK, nullptr, |
| " 0x%x %s 0x%x", (unsigned) *a, (*a == *b) ? "==" : "!=", (unsigned) *b); |
| a++; |
| b++; |
| } |
| return false; |
| } |
| |
| return links_equal (obj.real_links, other.obj.real_links, graph, other_graph, depth); |
| } |
| |
| hb_bytes_t as_bytes () const |
| { |
| return hb_bytes_t (obj.head, table_size ()); |
| } |
| |
| friend void swap (vertex_t& a, vertex_t& b) |
| { |
| hb_swap (a.obj, b.obj); |
| hb_swap (a.distance, b.distance); |
| hb_swap (a.space, b.space); |
| hb_swap (a.single_parent, b.single_parent); |
| hb_swap (a.parents, b.parents); |
| hb_swap (a.incoming_edges_, b.incoming_edges_); |
| hb_swap (a.start, b.start); |
| hb_swap (a.end, b.end); |
| hb_swap (a.priority, b.priority); |
| } |
| |
| hb_hashmap_t<unsigned, unsigned> |
| position_to_index_map () const |
| { |
| hb_hashmap_t<unsigned, unsigned> result; |
| |
| result.alloc (obj.real_links.length); |
| for (const auto& l : obj.real_links) { |
| result.set (l.position, l.objidx); |
| } |
| |
| return result; |
| } |
| |
| bool is_shared () const |
| { |
| return parents.get_population () > 1; |
| } |
| |
| unsigned incoming_edges () const |
| { |
| if (HB_DEBUG_SUBSET_REPACK) |
| { |
| assert (incoming_edges_ == (single_parent != (unsigned) -1) + |
| (parents.values_ref () | hb_reduce (hb_add, 0))); |
| } |
| return incoming_edges_; |
| } |
| |
| void reset_parents () |
| { |
| incoming_edges_ = 0; |
| single_parent = (unsigned) -1; |
| parents.reset (); |
| } |
| |
| void add_parent (unsigned parent_index) |
| { |
| assert (parent_index != (unsigned) -1); |
| if (incoming_edges_ == 0) |
| { |
| single_parent = parent_index; |
| incoming_edges_ = 1; |
| return; |
| } |
| else if (single_parent != (unsigned) -1) |
| { |
| assert (incoming_edges_ == 1); |
| if (!parents.set (single_parent, 1)) |
| return; |
| single_parent = (unsigned) -1; |
| } |
| |
| unsigned *v; |
| if (parents.has (parent_index, &v)) |
| { |
| (*v)++; |
| incoming_edges_++; |
| } |
| else if (parents.set (parent_index, 1)) |
| incoming_edges_++; |
| } |
| |
| void remove_parent (unsigned parent_index) |
| { |
| if (parent_index == single_parent) |
| { |
| single_parent = (unsigned) -1; |
| incoming_edges_--; |
| return; |
| } |
| |
| unsigned *v; |
| if (parents.has (parent_index, &v)) |
| { |
| incoming_edges_--; |
| if (*v > 1) |
| (*v)--; |
| else |
| parents.del (parent_index); |
| |
| if (incoming_edges_ == 1) |
| { |
| single_parent = *parents.keys (); |
| parents.reset (); |
| } |
| } |
| } |
| |
| void remove_real_link (unsigned child_index, const void* offset) |
| { |
| unsigned count = obj.real_links.length; |
| for (unsigned i = 0; i < count; i++) |
| { |
| auto& link = obj.real_links.arrayZ[i]; |
| if (link.objidx != child_index) |
| continue; |
| |
| if ((obj.head + link.position) != offset) |
| continue; |
| |
| obj.real_links.remove_unordered (i); |
| return; |
| } |
| } |
| |
| bool remap_parents (const hb_vector_t<unsigned>& id_map) |
| { |
| if (single_parent != (unsigned) -1) |
| { |
| assert (single_parent < id_map.length); |
| single_parent = id_map[single_parent]; |
| return true; |
| } |
| |
| hb_hashmap_t<unsigned, unsigned> new_parents; |
| new_parents.alloc (parents.get_population ()); |
| for (auto _ : parents) |
| { |
| assert (_.first < id_map.length); |
| assert (!new_parents.has (id_map[_.first])); |
| new_parents.set (id_map[_.first], _.second); |
| } |
| |
| if (parents.in_error() || new_parents.in_error ()) |
| return false; |
| |
| parents = std::move (new_parents); |
| return true; |
| } |
| |
| void remap_parent (unsigned old_index, unsigned new_index) |
| { |
| if (single_parent != (unsigned) -1) |
| { |
| if (single_parent == old_index) |
| single_parent = new_index; |
| return; |
| } |
| |
| const unsigned *pv; |
| if (parents.has (old_index, &pv)) |
| { |
| unsigned v = *pv; |
| if (!parents.set (new_index, v)) |
| incoming_edges_ -= v; |
| parents.del (old_index); |
| |
| if (incoming_edges_ == 1) |
| { |
| single_parent = *parents.keys (); |
| parents.reset (); |
| } |
| } |
| } |
| |
| bool is_leaf () const |
| { |
| return !obj.real_links.length && !obj.virtual_links.length; |
| } |
| |
| bool raise_priority () |
| { |
| if (has_max_priority ()) return false; |
| priority++; |
| return true; |
| } |
| |
| bool has_max_priority () const { |
| return priority >= 3; |
| } |
| |
| size_t table_size () const { |
| return obj.tail - obj.head; |
| } |
| |
| int64_t modified_distance (unsigned order) const |
| { |
| // TODO(garretrieger): once priority is high enough, should try |
| // setting distance = 0 which will force to sort immediately after |
| // it's parent where possible. |
| |
| int64_t modified_distance = |
| hb_min (hb_max(distance + distance_modifier (), 0), 0x7FFFFFFFFFF); |
| if (has_max_priority ()) { |
| modified_distance = 0; |
| } |
| return (modified_distance << 18) | (0x003FFFF & order); |
| } |
| |
| int64_t distance_modifier () const |
| { |
| if (!priority) return 0; |
| int64_t table_size = obj.tail - obj.head; |
| |
| if (priority == 1) |
| return -table_size / 2; |
| |
| return -table_size; |
| } |
| |
| private: |
| bool links_equal (const hb_vector_t<hb_serialize_context_t::object_t::link_t>& this_links, |
| const hb_vector_t<hb_serialize_context_t::object_t::link_t>& other_links, |
| const graph_t& graph, |
| const graph_t& other_graph, |
| unsigned depth) const |
| { |
| auto a = this_links.iter (); |
| auto b = other_links.iter (); |
| |
| while (a && b) |
| { |
| const auto& link_a = *a; |
| const auto& link_b = *b; |
| |
| if (link_a.width != link_b.width || |
| link_a.is_signed != link_b.is_signed || |
| link_a.whence != link_b.whence || |
| link_a.position != link_b.position || |
| link_a.bias != link_b.bias) |
| return false; |
| |
| if (!graph.vertices_[link_a.objidx].equals ( |
| other_graph.vertices_[link_b.objidx], graph, other_graph, depth + 1)) |
| return false; |
| |
| a++; |
| b++; |
| } |
| |
| if (bool (a) != bool (b)) |
| return false; |
| |
| return true; |
| } |
| }; |
| |
| template <typename T> |
| struct vertex_and_table_t |
| { |
| vertex_and_table_t () : index (0), vertex (nullptr), table (nullptr) |
| {} |
| |
| unsigned index; |
| vertex_t* vertex; |
| T* table; |
| |
| operator bool () { |
| return table && vertex; |
| } |
| }; |
| |
| /* |
| * A topological sorting of an object graph. Ordered |
| * in reverse serialization order (first object in the |
| * serialization is at the end of the list). This matches |
| * the 'packed' object stack used internally in the |
| * serializer |
| */ |
| template<typename T> |
| graph_t (const T& objects) |
| : parents_invalid (true), |
| distance_invalid (true), |
| positions_invalid (true), |
| successful (true), |
| buffers () |
| { |
| num_roots_for_space_.push (1); |
| bool removed_nil = false; |
| vertices_.alloc (objects.length); |
| vertices_scratch_.alloc (objects.length); |
| unsigned count = objects.length; |
| for (unsigned i = 0; i < count; i++) |
| { |
| // If this graph came from a serialization buffer object 0 is the |
| // nil object. We don't need it for our purposes here so drop it. |
| if (i == 0 && !objects.arrayZ[i]) |
| { |
| removed_nil = true; |
| continue; |
| } |
| |
| vertex_t* v = vertices_.push (); |
| if (check_success (!vertices_.in_error ())) |
| v->obj = *objects.arrayZ[i]; |
| |
| check_success (v->link_positions_valid (count, removed_nil)); |
| |
| if (!removed_nil) continue; |
| // Fix indices to account for removed nil object. |
| for (auto& l : v->obj.all_links_writer ()) { |
| l.objidx--; |
| } |
| } |
| } |
| |
| ~graph_t () |
| { |
| for (char* b : buffers) |
| hb_free (b); |
| } |
| |
| bool operator== (const graph_t& other) const |
| { |
| return root ().equals (other.root (), *this, other, 0); |
| } |
| |
| void print () const { |
| for (int i = vertices_.length - 1; i >= 0; i--) |
| { |
| const auto& v = vertices_[i]; |
| printf("%d: %u [", i, (unsigned int)v.table_size()); |
| for (const auto &l : v.obj.real_links) { |
| printf("%u, ", l.objidx); |
| } |
| printf("]\n"); |
| } |
| } |
| |
| // Sorts links of all objects in a consistent manner and zeroes all offsets. |
| void normalize () |
| { |
| for (auto& v : vertices_.writer ()) |
| v.normalize (); |
| } |
| |
| bool in_error () const |
| { |
| return !successful || |
| vertices_.in_error () || |
| num_roots_for_space_.in_error (); |
| } |
| |
| const vertex_t& root () const |
| { |
| return vertices_[root_idx ()]; |
| } |
| |
| unsigned root_idx () const |
| { |
| // Object graphs are in reverse order, the first object is at the end |
| // of the vector. Since the graph is topologically sorted it's safe to |
| // assume the first object has no incoming edges. |
| return vertices_.length - 1; |
| } |
| |
| const hb_serialize_context_t::object_t& object (unsigned i) const |
| { |
| return vertices_[i].obj; |
| } |
| |
| bool add_buffer (char* buffer) |
| { |
| buffers.push (buffer); |
| return !buffers.in_error (); |
| } |
| |
| /* |
| * Adds a 16 bit link from parent_id to child_id |
| */ |
| template<typename T> |
| void add_link (T* offset, |
| unsigned parent_id, |
| unsigned child_id) |
| { |
| auto& v = vertices_[parent_id]; |
| auto* link = v.obj.real_links.push (); |
| link->width = 2; |
| link->objidx = child_id; |
| link->position = (char*) offset - (char*) v.obj.head; |
| vertices_[child_id].add_parent (parent_id); |
| } |
| |
| /* |
| * Generates a new topological sorting of graph ordered by the shortest |
| * distance to each node if positions are marked as invalid. |
| */ |
| void sort_shortest_distance_if_needed () |
| { |
| if (!positions_invalid) return; |
| sort_shortest_distance (); |
| } |
| |
| |
| /* |
| * Generates a new topological sorting of graph ordered by the shortest |
| * distance to each node. |
| */ |
| void sort_shortest_distance () |
| { |
| positions_invalid = true; |
| |
| if (vertices_.length <= 1) { |
| // Graph of 1 or less doesn't need sorting. |
| return; |
| } |
| |
| update_distances (); |
| |
| hb_priority_queue_t queue; |
| hb_vector_t<vertex_t> &sorted_graph = vertices_scratch_; |
| 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_parents (); |
| |
| queue.insert (root ().modified_distance (0), root_idx ()); |
| int new_id = root_idx (); |
| unsigned order = 1; |
| while (!queue.in_error () && !queue.is_empty ()) |
| { |
| unsigned next_id = queue.pop_minimum().second; |
| |
| sorted_graph[new_id] = std::move (vertices_[next_id]); |
| const vertex_t& next = sorted_graph[new_id]; |
| |
| if (unlikely (!check_success(new_id >= 0))) { |
| // We are out of ids. Which means we've visited a node more than once. |
| // This graph contains a cycle which is not allowed. |
| DEBUG_MSG (SUBSET_REPACK, nullptr, "Invalid graph. Contains cycle."); |
| return; |
| } |
| |
| id_map[next_id] = new_id--; |
| |
| for (const auto& link : next.obj.all_links ()) { |
| 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 |
| // distance they'll be added to the topological order in the order that they are |
| // referenced from the parent object. |
| queue.insert (vertices_[link.objidx].modified_distance (order++), |
| link.objidx); |
| } |
| } |
| |
| check_success (!queue.in_error ()); |
| check_success (!sorted_graph.in_error ()); |
| |
| check_success (remap_all_obj_indices (id_map, &sorted_graph)); |
| vertices_ = std::move (sorted_graph); |
| |
| if (!check_success (new_id == -1)) |
| print_orphaned_nodes (); |
| } |
| |
| /* |
| * Finds the set of nodes (placed into roots) that should be assigned unique spaces. |
| * More specifically this looks for the top most 24 bit or 32 bit links in the graph. |
| * Some special casing is done that is specific to the layout of GSUB/GPOS tables. |
| */ |
| void find_space_roots (hb_set_t& visited, hb_set_t& roots) |
| { |
| int root_index = (int) root_idx (); |
| for (int i = root_index; i >= 0; i--) |
| { |
| if (visited.has (i)) continue; |
| |
| // Only real links can form 32 bit spaces |
| for (auto& l : vertices_[i].obj.real_links) |
| { |
| if (l.is_signed || l.width < 3) |
| continue; |
| |
| if (i == root_index && l.width == 3) |
| // Ignore 24bit links from the root node, this skips past the single 24bit |
| // pointer to the lookup list. |
| continue; |
| |
| if (l.width == 3) |
| { |
| // A 24bit offset forms a root, unless there is 32bit offsets somewhere |
| // in it's subgraph, then those become the roots instead. This is to make sure |
| // that extension subtables beneath a 24bit lookup become the spaces instead |
| // of the offset to the lookup. |
| hb_set_t sub_roots; |
| find_32bit_roots (l.objidx, sub_roots); |
| if (sub_roots) { |
| for (unsigned sub_root_idx : sub_roots) { |
| roots.add (sub_root_idx); |
| find_subgraph (sub_root_idx, visited); |
| } |
| continue; |
| } |
| } |
| |
| roots.add (l.objidx); |
| find_subgraph (l.objidx, visited); |
| } |
| } |
| } |
| |
| template <typename T, typename ...Ts> |
| vertex_and_table_t<T> as_table (unsigned parent, const void* offset, Ts... ds) |
| { |
| return as_table_from_index<T> (index_for_offset (parent, offset), std::forward<Ts>(ds)...); |
| } |
| |
| template <typename T, typename ...Ts> |
| vertex_and_table_t<T> as_mutable_table (unsigned parent, const void* offset, Ts... ds) |
| { |
| return as_table_from_index<T> (mutable_index_for_offset (parent, offset), std::forward<Ts>(ds)...); |
| } |
| |
| template <typename T, typename ...Ts> |
| vertex_and_table_t<T> as_table_from_index (unsigned index, Ts... ds) |
| { |
| if (index >= vertices_.length) |
| return vertex_and_table_t<T> (); |
| |
| vertex_and_table_t<T> r; |
| r.vertex = &vertices_[index]; |
| r.table = (T*) r.vertex->obj.head; |
| r.index = index; |
| if (!r.table) |
| return vertex_and_table_t<T> (); |
| |
| if (!r.table->sanitize (*(r.vertex), std::forward<Ts>(ds)...)) |
| return vertex_and_table_t<T> (); |
| |
| return r; |
| } |
| |
| // Finds the object id of the object pointed to by the offset at 'offset' |
| // within object[node_idx]. |
| unsigned index_for_offset (unsigned node_idx, const void* offset) const |
| { |
| const auto& node = object (node_idx); |
| if (offset < node.head || offset >= node.tail) return -1; |
| |
| unsigned count = node.real_links.length; |
| for (unsigned i = 0; i < count; i++) |
| { |
| // Use direct access for increased performance, this is a hot method. |
| const auto& link = node.real_links.arrayZ[i]; |
| if (offset != node.head + link.position) |
| continue; |
| return link.objidx; |
| } |
| |
| return -1; |
| } |
| |
| // Finds the object id of the object pointed to by the offset at 'offset' |
| // within object[node_idx]. Ensures that the returned object is safe to mutate. |
| // That is, if the original child object is shared by parents other than node_idx |
| // it will be duplicated and the duplicate will be returned instead. |
| unsigned mutable_index_for_offset (unsigned node_idx, const void* offset) |
| { |
| unsigned child_idx = index_for_offset (node_idx, offset); |
| auto& child = vertices_[child_idx]; |
| for (unsigned p : child.parents_iter ()) |
| { |
| if (p != node_idx) { |
| return duplicate (node_idx, child_idx); |
| } |
| } |
| |
| return child_idx; |
| } |
| |
| |
| /* |
| * Assign unique space numbers to each connected subgraph of 24 bit and/or 32 bit offset(s). |
| * Currently, this is implemented specifically tailored to the structure of a GPOS/GSUB |
| * (including with 24bit offsets) table. |
| */ |
| bool assign_spaces () |
| { |
| update_parents (); |
| |
| hb_set_t visited; |
| hb_set_t roots; |
| find_space_roots (visited, roots); |
| |
| // Mark everything not in the subgraphs of the roots as visited. This prevents |
| // subgraphs from being connected via nodes not in those subgraphs. |
| visited.invert (); |
| |
| if (!roots) return false; |
| |
| while (roots) |
| { |
| uint32_t next = HB_SET_VALUE_INVALID; |
| if (unlikely (!check_success (!roots.in_error ()))) break; |
| if (!roots.next (&next)) break; |
| |
| hb_set_t connected_roots; |
| find_connected_nodes (next, roots, visited, connected_roots); |
| if (unlikely (!check_success (!connected_roots.in_error ()))) break; |
| |
| isolate_subgraph (connected_roots); |
| if (unlikely (!check_success (!connected_roots.in_error ()))) break; |
| |
| 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_map_t 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); |
| } |
| if (subgraph.in_error ()) |
| return false; |
| |
| unsigned original_root_idx = root_idx (); |
| hb_map_t index_map; |
| bool made_changes = false; |
| for (auto entry : subgraph.iter ()) |
| { |
| assert (entry.first < vertices_.length); |
| 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 (in_error ()) |
| return false; |
| |
| 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([&] (uint32_t node_idx) { |
| const uint32_t *v; |
| if (index_map.has (node_idx, &v)) return *v; |
| 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. |
| for (auto next : roots) |
| { |
| const uint32_t *v; |
| if (index_map.has (next, &v)) |
| { |
| roots.del (next); |
| roots.add (*v); |
| } |
| } |
| |
| return true; |
| } |
| |
| void find_subgraph (unsigned node_idx, hb_map_t& subgraph) |
| { |
| for (const auto& link : vertices_[node_idx].obj.all_links ()) |
| { |
| hb_codepoint_t *v; |
| if (subgraph.has (link.objidx, &v)) |
| { |
| (*v)++; |
| 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.all_links ()) |
| find_subgraph (link.objidx, subgraph); |
| } |
| |
| size_t find_subgraph_size (unsigned node_idx, hb_set_t& subgraph, unsigned max_depth = -1) |
| { |
| if (subgraph.has (node_idx)) return 0; |
| subgraph.add (node_idx); |
| |
| const auto& o = vertices_[node_idx].obj; |
| size_t size = o.tail - o.head; |
| if (max_depth == 0) |
| return size; |
| |
| for (const auto& link : o.all_links ()) |
| size += find_subgraph_size (link.objidx, subgraph, max_depth - 1); |
| return size; |
| } |
| |
| /* |
| * Finds the topmost children of 32bit offsets in the subgraph starting |
| * at node_idx. Found indices are placed into 'found'. |
| */ |
| void find_32bit_roots (unsigned node_idx, hb_set_t& found) |
| { |
| for (const auto& link : vertices_[node_idx].obj.all_links ()) |
| { |
| if (!link.is_signed && link.width == 4) { |
| found.add (link.objidx); |
| continue; |
| } |
| find_32bit_roots (link.objidx, found); |
| } |
| } |
| |
| /* |
| * Moves the child of old_parent_idx pointed to by old_offset to a new |
| * vertex at the new_offset. |
| */ |
| template<typename O> |
| void move_child (unsigned old_parent_idx, |
| const O* old_offset, |
| unsigned new_parent_idx, |
| const O* new_offset) |
| { |
| distance_invalid = true; |
| positions_invalid = true; |
| |
| auto& old_v = vertices_[old_parent_idx]; |
| auto& new_v = vertices_[new_parent_idx]; |
| |
| unsigned child_id = index_for_offset (old_parent_idx, |
| old_offset); |
| |
| auto* new_link = new_v.obj.real_links.push (); |
| new_link->width = O::static_size; |
| new_link->objidx = child_id; |
| new_link->position = (const char*) new_offset - (const char*) new_v.obj.head; |
| |
| auto& child = vertices_[child_id]; |
| child.add_parent (new_parent_idx); |
| |
| old_v.remove_real_link (child_id, old_offset); |
| child.remove_parent (old_parent_idx); |
| } |
| |
| /* |
| * 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_map_t& index_map) |
| { |
| if (index_map.has (node_idx)) |
| return; |
| |
| unsigned clone_idx = duplicate (node_idx); |
| if (!check_success (clone_idx != (unsigned) -1)) |
| return; |
| |
| index_map.set (node_idx, clone_idx); |
| for (const auto& l : object (node_idx).all_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_[node_idx]; |
| if (vertices_.in_error ()) { |
| return -1; |
| } |
| |
| clone->obj.head = child.obj.head; |
| clone->obj.tail = child.obj.tail; |
| clone->distance = child.distance; |
| clone->space = child.space; |
| clone->reset_parents (); |
| |
| unsigned clone_idx = vertices_.length - 2; |
| for (const auto& l : child.obj.real_links) |
| { |
| clone->obj.real_links.push (l); |
| vertices_[l.objidx].add_parent (clone_idx); |
| } |
| for (const auto& l : child.obj.virtual_links) |
| { |
| clone->obj.virtual_links.push (l); |
| vertices_[l.objidx].add_parent (clone_idx); |
| } |
| |
| check_success (!clone->obj.real_links.in_error ()); |
| check_success (!clone->obj.virtual_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. |
| hb_swap (vertices_[vertices_.length - 2], *clone); |
| |
| // Since the root moved, update the parents arrays of all children on the root. |
| for (const auto& l : root ().obj.all_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. |
| */ |
| unsigned duplicate_if_shared (unsigned parent_idx, unsigned child_idx) |
| { |
| unsigned new_idx = duplicate (parent_idx, child_idx); |
| if (new_idx == (unsigned) -1) return child_idx; |
| return new_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. |
| */ |
| unsigned duplicate (unsigned parent_idx, unsigned child_idx) |
| { |
| update_parents (); |
| |
| unsigned links_to_child = 0; |
| for (const auto& l : vertices_[parent_idx].obj.all_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 %u => %u", |
| parent_idx, child_idx); |
| return -1; |
| } |
| |
| DEBUG_MSG (SUBSET_REPACK, nullptr, " Duplicating %u => %u", |
| 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]; |
| for (auto& l : parent.obj.all_links_writer ()) |
| { |
| if (l.objidx != child_idx) |
| continue; |
| |
| reassign_link (l, parent_idx, clone_idx); |
| } |
| |
| return clone_idx; |
| } |
| |
| |
| /* |
| * Adds a new node to the graph, not connected to anything. |
| */ |
| unsigned new_node (char* head, char* tail) |
| { |
| positions_invalid = true; |
| distance_invalid = true; |
| |
| auto* clone = vertices_.push (); |
| if (vertices_.in_error ()) { |
| return -1; |
| } |
| |
| clone->obj.head = head; |
| clone->obj.tail = tail; |
| clone->distance = 0; |
| clone->space = 0; |
| |
| unsigned clone_idx = vertices_.length - 2; |
| |
| // 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. |
| hb_swap (vertices_[vertices_.length - 2], *clone); |
| |
| // Since the root moved, update the parents arrays of all children on the root. |
| for (const auto& l : root ().obj.all_links ()) |
| vertices_[l.objidx].remap_parent (root_idx () - 1, root_idx ()); |
| |
| return clone_idx; |
| } |
| |
| /* |
| * Raises the sorting priority of all children. |
| */ |
| bool raise_childrens_priority (unsigned parent_idx) |
| { |
| DEBUG_MSG (SUBSET_REPACK, nullptr, " Raising priority of all children of %u", |
| parent_idx); |
| // This operation doesn't change ordering until a sort is run, so no need |
| // to invalidate positions. It does not change graph structure so no need |
| // to update distances or edge counts. |
| auto& parent = vertices_[parent_idx].obj; |
| bool made_change = false; |
| for (auto& l : parent.all_links_writer ()) |
| made_change |= vertices_[l.objidx].raise_priority (); |
| return made_change; |
| } |
| |
| bool is_fully_connected () |
| { |
| update_parents(); |
| |
| if (root().incoming_edges ()) |
| // Root cannot have parents. |
| return false; |
| |
| for (unsigned i = 0; i < root_idx (); i++) |
| { |
| if (!vertices_[i].incoming_edges ()) |
| return false; |
| } |
| return true; |
| } |
| |
| #if 0 |
| /* |
| * Saves the current graph to a packed binary format which the repacker fuzzer takes |
| * as a seed. |
| */ |
| void save_fuzzer_seed (hb_tag_t tag) const |
| { |
| FILE* f = fopen ("./repacker_fuzzer_seed", "w"); |
| fwrite ((void*) &tag, sizeof (tag), 1, f); |
| |
| uint16_t num_objects = vertices_.length; |
| fwrite ((void*) &num_objects, sizeof (num_objects), 1, f); |
| |
| for (const auto& v : vertices_) |
| { |
| uint16_t blob_size = v.table_size (); |
| fwrite ((void*) &blob_size, sizeof (blob_size), 1, f); |
| fwrite ((const void*) v.obj.head, blob_size, 1, f); |
| } |
| |
| uint16_t link_count = 0; |
| for (const auto& v : vertices_) |
| link_count += v.obj.real_links.length; |
| |
| fwrite ((void*) &link_count, sizeof (link_count), 1, f); |
| |
| typedef struct |
| { |
| uint16_t parent; |
| uint16_t child; |
| uint16_t position; |
| uint8_t width; |
| } link_t; |
| |
| for (unsigned i = 0; i < vertices_.length; i++) |
| { |
| for (const auto& l : vertices_[i].obj.real_links) |
| { |
| link_t link { |
| (uint16_t) i, (uint16_t) l.objidx, |
| (uint16_t) l.position, (uint8_t) l.width |
| }; |
| fwrite ((void*) &link, sizeof (link), 1, f); |
| } |
| } |
| |
| fclose (f); |
| } |
| #endif |
| |
| 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(); |
| |
| if (root().incoming_edges ()) { |
| DEBUG_MSG (SUBSET_REPACK, nullptr, "Root node has incoming edges."); |
| } |
| |
| for (unsigned i = 0; i < root_idx (); i++) |
| { |
| const auto& v = vertices_[i]; |
| if (!v.incoming_edges ()) |
| DEBUG_MSG (SUBSET_REPACK, nullptr, "Node %u is orphaned.", i); |
| } |
| } |
| |
| 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 (const hb_set_t& indices) |
| { |
| num_roots_for_space_.push (0); |
| unsigned new_space = num_roots_for_space_.length - 1; |
| |
| for (unsigned index : indices) { |
| auto& node = vertices_[index]; |
| num_roots_for_space_[node.space] = num_roots_for_space_[node.space] - 1; |
| num_roots_for_space_[new_space] = num_roots_for_space_[new_space] + 1; |
| node.space = new_space; |
| distance_invalid = true; |
| positions_invalid = true; |
| } |
| } |
| |
| unsigned space_for (unsigned index, unsigned* root = nullptr) const |
| { |
| loop: |
| assert (index < vertices_.length); |
| const auto& node = vertices_[index]; |
| if (node.space) |
| { |
| if (root != nullptr) |
| *root = index; |
| return node.space; |
| } |
| |
| if (!node.incoming_edges ()) |
| { |
| if (root) |
| *root = index; |
| return 0; |
| } |
| |
| index = *node.parents_iter (); |
| goto loop; |
| } |
| |
| void err_other_error () { this->successful = false; } |
| |
| size_t total_size_in_bytes () const { |
| size_t total_size = 0; |
| unsigned count = vertices_.length; |
| for (unsigned i = 0; i < count; i++) { |
| size_t size = vertices_.arrayZ[i].obj.tail - vertices_.arrayZ[i].obj.head; |
| total_size += size; |
| } |
| return total_size; |
| } |
| |
| |
| private: |
| |
| /* |
| * Returns the numbers of incoming edges that are 24 or 32 bits wide. |
| */ |
| unsigned wide_parents (unsigned node_idx, hb_set_t& parents) const |
| { |
| unsigned count = 0; |
| for (unsigned p : vertices_[node_idx].parents_iter ()) |
| { |
| // Only real links can be wide |
| for (const auto& l : vertices_[p].obj.real_links) |
| { |
| if (l.objidx == node_idx |
| && (l.width == 3 || l.width == 4) |
| && !l.is_signed) |
| { |
| count++; |
| parents.add (p); |
| } |
| } |
| } |
| return count; |
| } |
| |
| bool check_success (bool success) |
| { return this->successful && (success || ((void) err_other_error (), false)); } |
| |
| public: |
| /* |
| * Creates a map from objid to # of incoming edges. |
| */ |
| void update_parents () |
| { |
| if (!parents_invalid) return; |
| |
| unsigned count = vertices_.length; |
| |
| for (unsigned i = 0; i < count; i++) |
| vertices_.arrayZ[i].reset_parents (); |
| |
| for (unsigned p = 0; p < count; p++) |
| { |
| for (auto& l : vertices_.arrayZ[p].obj.all_links ()) |
| vertices_[l.objidx].add_parent (p); |
| } |
| |
| for (unsigned i = 0; i < count; i++) |
| // parents arrays must be accurate or downstream operations like cycle detection |
| // and sorting won't work correctly. |
| check_success (!vertices_.arrayZ[i].in_error ()); |
| |
| parents_invalid = false; |
| } |
| |
| /* |
| * compute the serialized start and end positions for each vertex. |
| */ |
| void update_positions () |
| { |
| if (!positions_invalid) return; |
| |
| unsigned current_pos = 0; |
| for (int i = root_idx (); i >= 0; i--) |
| { |
| auto& v = vertices_[i]; |
| v.start = current_pos; |
| current_pos += v.obj.tail - v.obj.head; |
| v.end = current_pos; |
| } |
| |
| positions_invalid = false; |
| } |
| |
| /* |
| * Finds the distance to each object in the graph |
| * from the initial node. |
| */ |
| void update_distances () |
| { |
| if (!distance_invalid) return; |
| |
| // Uses Dijkstra's algorithm to find all of the shortest distances. |
| // https://en.wikipedia.org/wiki/Dijkstra%27s_algorithm |
| // |
| // Implementation Note: |
| // Since our priority queue doesn't support fast priority decreases |
| // we instead just add new entries into the queue when a priority changes. |
| // Redundant ones are filtered out later on by the visited set. |
| // According to https://www3.cs.stonybrook.edu/~rezaul/papers/TR-07-54.pdf |
| // for practical performance this is faster then using a more advanced queue |
| // (such as a fibonacci queue) with a fast decrease priority. |
| unsigned count = vertices_.length; |
| for (unsigned i = 0; i < count; i++) |
| vertices_.arrayZ[i].distance = hb_int_max (int64_t); |
| vertices_.tail ().distance = 0; |
| |
| hb_priority_queue_t queue; |
| queue.insert (0, vertices_.length - 1); |
| |
| 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[next_idx]) continue; |
| const auto& next = vertices_[next_idx]; |
| int64_t next_distance = vertices_[next_idx].distance; |
| visited[next_idx] = true; |
| |
| for (const auto& link : next.obj.all_links ()) |
| { |
| if (visited[link.objidx]) continue; |
| |
| const auto& child = vertices_.arrayZ[link.objidx].obj; |
| 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_.arrayZ[link.objidx].space + 1); |
| int64_t child_distance = next_distance + child_weight; |
| |
| if (child_distance < vertices_.arrayZ[link.objidx].distance) |
| { |
| vertices_.arrayZ[link.objidx].distance = child_distance; |
| queue.insert (child_distance, link.objidx); |
| } |
| } |
| } |
| |
| check_success (!queue.in_error ()); |
| if (!check_success (queue.is_empty ())) |
| { |
| print_orphaned_nodes (); |
| return; |
| } |
| |
| distance_invalid = false; |
| } |
| |
| private: |
| /* |
| * 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].add_parent (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_map_t& id_map, |
| Iterator subgraph, |
| bool only_wide = false) |
| { |
| if (!id_map) return; |
| for (unsigned i : subgraph) |
| { |
| for (auto& link : vertices_[i].obj.all_links_writer ()) |
| { |
| const uint32_t *v; |
| if (!id_map.has (link.objidx, &v)) continue; |
| if (only_wide && !(link.width == 4 && !link.is_signed)) continue; |
| |
| reassign_link (link, i, *v); |
| } |
| } |
| } |
| |
| /* |
| * Updates all objidx's in all links using the provided mapping. |
| */ |
| bool remap_all_obj_indices (const hb_vector_t<unsigned>& id_map, |
| hb_vector_t<vertex_t>* sorted_graph) const |
| { |
| unsigned count = sorted_graph->length; |
| for (unsigned i = 0; i < count; i++) |
| { |
| if (!(*sorted_graph)[i].remap_parents (id_map)) |
| return false; |
| for (auto& link : sorted_graph->arrayZ[i].obj.all_links_writer ()) |
| { |
| link.objidx = id_map[link.objidx]; |
| } |
| } |
| return true; |
| } |
| |
| /* |
| * 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 (unlikely (!check_success (!visited.in_error ()))) return; |
| 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.all_links ()) |
| find_connected_nodes (l.objidx, targets, visited, connected); |
| |
| for (unsigned p : v.parents_iter ()) |
| 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_; |
| hb_vector_t<vertex_t> vertices_scratch_; |
| private: |
| bool parents_invalid; |
| bool distance_invalid; |
| bool positions_invalid; |
| bool successful; |
| hb_vector_t<unsigned> num_roots_for_space_; |
| hb_vector_t<char*> buffers; |
| }; |
| |
| } |
| |
| #endif // GRAPH_GRAPH_HH |
