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// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <stddef.h>
#include <stdint.h>
#include <vector>
#include "base/macros.h"
#include "components/zucchini/image_utils.h"
namespace zucchini {
class EquivalenceMap;
// Computes and stores affinity between old and new targets for a single target
// pool. This is only used during patch generation.
class TargetsAffinity {
// Infers affinity between |old_targets| and |new_targets| using similarities
// described by |equivalence_map|, and updates internal state for retrieval of
// affinity scores. Both |old_targets| and |new_targets| are targets in the
// same pool and are sorted in ascending order.
void InferFromSimilarities(const EquivalenceMap& equivalence_map,
const std::vector<offset_t>& old_targets,
const std::vector<offset_t>& new_targets);
// Assigns labels to targets based on associations previously inferred, using
// |min_affinity| to reject associations with weak |affinity|. Label 0 is
// assigned to unassociated targets. Labels for old targets are written to
// |old_labels| and labels for new targets are written to |new_labels|.
// Returns the upper bound on assigned labels (>= 1 since 0 is used).
uint32_t AssignLabels(double min_affinity,
std::vector<uint32_t>* old_labels,
std::vector<uint32_t>* new_labels);
// Returns the affinity score between targets identified by |old_key| and
// |new_keys|. Affinity > 0 means an association is likely, < 0 means
// incompatible association, and 0 means neither targets have been associated.
double AffinityBetween(key_t old_key, key_t new_key) const;
struct Association {
key_t other = 0;
double affinity = 0.0;
// Forward and backward associations between old and new targets. For each
// Association element, if |affinity == 0.0| then no association is defined
// (and |other| is meaningless|. Otherwise |affinity > 0.0|, and the
// association between |old_labels[old_key]| and |new_labels[new_key]| is
// represented by:
// forward_association_[old_key].other == new_key;
// backward_association_[new_key].other == old_key;
// forward_association_[old_key].affinity ==
// backward_association_[new_key].affinity;
// The two lists contain the same information, but having both enables quick
// lookup, given |old_key| or |new_key|.
std::vector<Association> forward_association_;
std::vector<Association> backward_association_;
} // namespace zucchini