Python2/PyMuPDF: mupdf-source/thirdparty/harfbuzz/src/graph/graph.hh comparison

comparison mupdf-source/thirdparty/harfbuzz/src/graph/graph.hh @ 2:b50eed0cc0ef upstream

ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.

author	Franz Glasner <fzglas.hg@dom66.de>
date	Mon, 15 Sep 2025 11:43:07 +0200
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children

comparison

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-:1d09e1dec1d9
+:b50eed0cc0ef
+/*
+* 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 ;
+int64_t space = 0 ;
+hb_vector_t<unsigned> parents;
+unsigned start = 0;
+unsigned end = 0;
+unsigned priority = 0;
+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", *a, (*a == *b) ? "==" : "!=", *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.parents, b.parents);
+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;
+for (const auto& l : obj.real_links) {
+result.set (l.position, l.objidx);
+}
+return result;
+}
+bool is_shared () const
+{
+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_unordered (i);
+break;
+}
+}
+void remove_real_link (unsigned child_index, const void* offset)
+{
+for (unsigned i = 0; i < obj.real_links.length; 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;
+}
+}
+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
+{
+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);
+for (unsigned i = 0; i < objects.length; 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[i])
+{
+removed_nil = true;
+continue;
+}
+vertex_t* v = vertices_.push ();
+if (check_success (!vertices_.in_error ()))
+v->obj = *objects[i];
+check_success (v->link_positions_valid (objects.length, 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 ()
+{
+vertices_.fini ();
+for (char* b : buffers)
+hb_free (b);
+}
+bool operator== (const graph_t& other) const
+{
+return root ().equals (other.root (), *this, other, 0);
+}
+// 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;
+}
+void add_buffer (char* buffer)
+{
+buffers.push (buffer);
+}
+/*
+* 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].parents.push (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;
+hb_swap (sorted_graph[new_id], 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 ());
+remap_all_obj_indices (id_map, &sorted_graph);
+hb_swap (vertices_, 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 length = node.real_links.length;
+for (unsigned i = 0; i < length; 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)
+{
+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);
+}
+unsigned original_root_idx = root_idx ();
+hb_map_t 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([&] (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.
+uint32_t next = HB_SET_VALUE_INVALID;
+while (roots.next (&next))
+{
+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 ())
+{
+const uint32_t *v;
+if (subgraph.has (link.objidx, &v))
+{
+subgraph.set (link.objidx, *v + 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.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.parents.push (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;
+index_map.set (node_idx, duplicate (node_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->parents.reset ();
+unsigned clone_idx = vertices_.length - 2;
+for (const auto& l : child.obj.real_links)
+{
+clone->obj.real_links.push (l);
+vertices_[l.objidx].parents.push (clone_idx);
+}
+for (const auto& l : child.obj.virtual_links)
+{
+clone->obj.virtual_links.push (l);
+vertices_[l.objidx].parents.push (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 %d => %d",
+parent_idx, child_idx);
+return -1;
+}
+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];
+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 %d",
+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().parents)
+// Root cannot have parents.
+return false;
+for (unsigned i = 0; i < root_idx (); i++)
+{
+if (!vertices_[i].parents)
+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().parents) {
+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.parents)
+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
+{
+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; }
+size_t total_size_in_bytes () const {
+size_t total_size = 0;
+for (unsigned i = 0; i < vertices_.length; i++) {
+size_t size = vertices_[i].obj.tail - vertices_[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;
+hb_set_t visited;
+for (unsigned p : vertices_[node_idx].parents)
+{
+if (visited.has (p)) continue;
+visited.add (p);
+// 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;
+for (unsigned i = 0; i < vertices_.length; i++)
+vertices_[i].parents.reset ();
+for (unsigned p = 0; p < vertices_.length; p++)
+{
+for (auto& l : vertices_[p].obj.all_links ())
+{
+vertices_[l.objidx].parents.push (p);
+}
+}
+for (unsigned i = 0; i < vertices_.length; i++)
+// parents arrays must be accurate or downstream operations like cycle detection
+// and sorting won't work correctly.
+check_success (!vertices_[i].parents.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.
+for (unsigned i = 0; i < vertices_.length; i++)
+{
+if (i == vertices_.length - 1)
+vertices_[i].distance = 0;
+else
+vertices_[i].distance = hb_int_max (int64_t);
+}
+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_[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_[link.objidx].space + 1);
+int64_t child_distance = next_distance + child_weight;
+if (child_distance < vertices_[link.objidx].distance)
+{
+vertices_[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].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_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.
+*/
+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 (auto& link : (*sorted_graph)[i].obj.all_links_writer ())
+{
+link.objidx = id_map[link.objidx];
+}
+}
+}
+/*
+* 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)
+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

Mercurial > hgrepos > Python2 > PyMuPDF

comparison mupdf-source/thirdparty/harfbuzz/src/graph/graph.hh @ 2:b50eed0cc0ef upstream