1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/base/id_map.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,105 @@
1.4 +// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +#ifndef BASE_ID_MAP_H__
1.9 +#define BASE_ID_MAP_H__
1.10 +
1.11 +#include "base/basictypes.h"
1.12 +#include "base/hash_tables.h"
1.13 +#include "base/logging.h"
1.14 +
1.15 +// This object maintains a list of IDs that can be quickly converted to
1.16 +// pointers to objects. It is implemented as a hash table, optimized for
1.17 +// relatively small data sets (in the common case, there will be exactly one
1.18 +// item in the list).
1.19 +//
1.20 +// Items can be inserted into the container with arbitrary ID, but the caller
1.21 +// must ensure they are unique. Inserting IDs and relying on automatically
1.22 +// generated ones is not allowed because they can collide.
1.23 +template<class T>
1.24 +class IDMap {
1.25 + private:
1.26 + typedef base::hash_map<int32_t, T*> HashTable;
1.27 + typedef typename HashTable::iterator iterator;
1.28 +
1.29 + public:
1.30 + // support const iterators over the items
1.31 + // Note, use iterator->first to get the ID, iterator->second to get the T*
1.32 + typedef typename HashTable::const_iterator const_iterator;
1.33 +
1.34 + IDMap() : next_id_(1) {
1.35 + }
1.36 + IDMap(const IDMap& other) : next_id_(other.next_id_),
1.37 + data_(other.data_) {
1.38 + }
1.39 +
1.40 + const_iterator begin() const {
1.41 + return data_.begin();
1.42 + }
1.43 + const_iterator end() const {
1.44 + return data_.end();
1.45 + }
1.46 +
1.47 + // Adds a view with an automatically generated unique ID. See AddWithID.
1.48 + int32_t Add(T* data) {
1.49 + int32_t this_id = next_id_;
1.50 + DCHECK(data_.find(this_id) == data_.end()) << "Inserting duplicate item";
1.51 + data_[this_id] = data;
1.52 + next_id_++;
1.53 + return this_id;
1.54 + }
1.55 +
1.56 + // Adds a new data member with the specified ID. The ID must not be in
1.57 + // the list. The caller either must generate all unique IDs itself and use
1.58 + // this function, or allow this object to generate IDs and call Add. These
1.59 + // two methods may not be mixed, or duplicate IDs may be generated
1.60 + void AddWithID(T* data, int32_t id) {
1.61 + DCHECK(data_.find(id) == data_.end()) << "Inserting duplicate item";
1.62 + data_[id] = data;
1.63 + }
1.64 +
1.65 + void Remove(int32_t id) {
1.66 + iterator i = data_.find(id);
1.67 + if (i == data_.end()) {
1.68 + NOTREACHED() << "Attempting to remove an item not in the list";
1.69 + return;
1.70 + }
1.71 + data_.erase(i);
1.72 + }
1.73 +
1.74 + bool IsEmpty() const {
1.75 + return data_.empty();
1.76 + }
1.77 +
1.78 + void Clear() {
1.79 + data_.clear();
1.80 + }
1.81 +
1.82 + bool HasData(const T* data) const {
1.83 + // XXX would like to use <algorithm> here ...
1.84 + for (const_iterator it = begin(); it != end(); ++it)
1.85 + if (data == it->second)
1.86 + return true;
1.87 + return false;
1.88 + }
1.89 +
1.90 + T* Lookup(int32_t id) const {
1.91 + const_iterator i = data_.find(id);
1.92 + if (i == data_.end())
1.93 + return NULL;
1.94 + return i->second;
1.95 + }
1.96 +
1.97 + size_t size() const {
1.98 + return data_.size();
1.99 + }
1.100 +
1.101 + protected:
1.102 + // The next ID that we will return from Add()
1.103 + int32_t next_id_;
1.104 +
1.105 + HashTable data_;
1.106 +};
1.107 +
1.108 +#endif // BASE_ID_MAP_H__
