chromium/components/language/content/browser/ulp_language_code_locator/s2langquadtree.h

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_LANGUAGE_CONTENT_BROWSER_ULP_LANGUAGE_CODE_LOCATOR_S2LANGQUADTREE_H_
#define COMPONENTS_LANGUAGE_CONTENT_BROWSER_ULP_LANGUAGE_CODE_LOCATOR_S2LANGQUADTREE_H_

#include <algorithm>
#include <bitset>
#include <map>
#include <string>
#include <vector>

#include "base/bits.h"

class S2CellId;

// A serialized language tree. The bits given by GetBitAt represent a
// depth-first traversal of the tree with (1) internal nodes represented by a
// single bit 0, and (2) leaf nodes represented by a bit 1 followed by the
// binary form of the index of the language at that leaf into the tree's
// languages, accessible through GetLanguageAt. We assume those indexes have the
// smallest number of bits necessary. Indices are 1-based; index 0 represents
// absent language.
class SerializedLanguageTree { … };

// An implementation of SerializedLanguageTree that backs the tree's structure
// by a bitset.
template <size_t numbits>
class BitsetSerializedLanguageTree : public SerializedLanguageTree { … };

// The node of a S2Cell-based quadtree holding string languages in its leaves.
class S2LangQuadTreeNode { … };

#endif  // COMPONENTS_LANGUAGE_CONTENT_BROWSER_ULP_LANGUAGE_CODE_LOCATOR_S2LANGQUADTREE_H_