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// Copyright (c) 2011 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.
#ifndef CHROME_BROWSER_CHROMEOS_CROS_ENUM_MAPPER_H_
#define CHROME_BROWSER_CHROMEOS_CROS_ENUM_MAPPER_H_
#include <map>
#include <string>
#include "base/basictypes.h"
namespace chromeos {
// This turns an array of string-to-enum-value mappings into a class
// that can cache the mapping and do quick lookups using an actual map
// class. Usage is something like:
//
// const char kKey1[] = "key1";
// const char kKey2[] = "key2";
//
// enum EnumFoo {
// UNKNOWN = 0,
// FOO = 1,
// BAR = 2,
// };
//
// const EnumMapper<EnumFoo>::Pair index_table[] = {
// { kKey1, FOO },
// { kKey2, BAR },
// };
//
// EnumMapper<EnumFoo> mapper(index_table, arraysize(index_table), UNKNOWN);
// EnumFoo value = mapper.Get(kKey1); // Returns FOO.
// EnumFoo value = mapper.Get('boo'); // Returns UNKNOWN.
template <typename EnumType>
class EnumMapper {
public:
struct Pair {
const char* key;
const EnumType value;
};
EnumMapper(const Pair* list, size_t num_entries, EnumType unknown)
: unknown_value_(unknown) {
for (size_t i = 0; i < num_entries; ++i, ++list) {
enum_map_[list->key] = list->value;
inverse_enum_map_[list->value] = list->key;
}
}
EnumType Get(const std::string& type) const {
EnumMapConstIter iter = enum_map_.find(type);
if (iter != enum_map_.end())
return iter->second;
return unknown_value_;
}
std::string GetKey(EnumType type) const {
InverseEnumMapConstIter iter = inverse_enum_map_.find(type);
if (iter != inverse_enum_map_.end())
return iter->second;
return std::string();
}
private:
typedef typename std::map<std::string, EnumType> EnumMap;
typedef typename std::map<EnumType, std::string> InverseEnumMap;
typedef typename EnumMap::const_iterator EnumMapConstIter;
typedef typename InverseEnumMap::const_iterator InverseEnumMapConstIter;
EnumMap enum_map_;
InverseEnumMap inverse_enum_map_;
EnumType unknown_value_;
DISALLOW_COPY_AND_ASSIGN(EnumMapper);
};
} // namespace chromeos
#endif // CHROME_BROWSER_CHROMEOS_CROS_ENUM_MAPPER_H_
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