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[repacker] extract overflows processing into its own method.

This commit is contained in:
Garret Rieger 2021-09-07 16:52:37 -07:00
parent b14b3f13ba
commit 8d8b7458a4
1 changed files with 51 additions and 51 deletions
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98
src/hb-repacker.hh
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@ -758,6 +758,53 @@ struct graph_t
bool successful;
};
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.
sorted_graph.duplicate (r.parent, r.child);
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.
// - Isolate the sub graphs of extension sub tables.
// - Table splitting.
}
return resolution_attempted;
}
/*
* Attempts to modify the topological sorting of the provided object graph to
@ -793,60 +840,14 @@ hb_resolve_overflows (const hb_vector_t<hb_serialize_context_t::object_t *>& pac
DEBUG_MSG (SUBSET_REPACK, nullptr, "=== Over flow 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 (!_process_overflows (overflows, priority_bumped_parents, sorted_graph))
{
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.
sorted_graph.duplicate (r.parent, r.child);
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.
// - Isolate the sub graphs of extension sub tables.
// - 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;
}
if (sorted_graph.in_error ())
@ -864,5 +865,4 @@ hb_resolve_overflows (const hb_vector_t<hb_serialize_context_t::object_t *>& pac
sorted_graph.serialize (c);
}
#endif /* HB_REPACKER_HH */