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// Copyright 2018 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Generates random values for testing. Specialized only for the few types we
// care about.
#ifndef ABSL_CONTAINER_INTERNAL_HASH_GENERATOR_TESTING_H_
#define ABSL_CONTAINER_INTERNAL_HASH_GENERATOR_TESTING_H_
#include <stdint.h>
#include <algorithm>
#include <cassert>
#include <iosfwd>
#include <random>
#include <tuple>
#include <type_traits>
#include <utility>
#include <vector>
#include "absl/container/internal/hash_policy_testing.h"
#include "absl/memory/memory.h"
#include "absl/meta/type_traits.h"
#include "absl/strings/string_view.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace container_internal {
namespace hash_internal {
namespace generator_internal {
template <class Container, class = void>
struct IsMap : std::false_type {};
template <class Map>
struct IsMap<Map, absl::void_t<typename Map::mapped_type>> : std::true_type {};
} // namespace generator_internal
std::mt19937_64* GetSharedRng();
enum Enum {
kEnumEmpty,
kEnumDeleted,
};
enum class EnumClass : uint64_t {
kEmpty,
kDeleted,
};
inline std::ostream& operator<<(std::ostream& o, const EnumClass& ec) {
return o << static_cast<uint64_t>(ec);
}
template <class T, class E = void>
struct Generator;
template <class T>
struct Generator<T, typename std::enable_if<std::is_integral<T>::value>::type> {
T operator()() const {
std::uniform_int_distribution<T> dist;
return dist(*GetSharedRng());
}
};
template <>
struct Generator<Enum> {
Enum operator()() const {
std::uniform_int_distribution<typename std::underlying_type<Enum>::type>
dist;
while (true) {
auto variate = dist(*GetSharedRng());
if (variate != kEnumEmpty && variate != kEnumDeleted)
return static_cast<Enum>(variate);
}
}
};
template <>
struct Generator<EnumClass> {
EnumClass operator()() const {
std::uniform_int_distribution<
typename std::underlying_type<EnumClass>::type>
dist;
while (true) {
EnumClass variate = static_cast<EnumClass>(dist(*GetSharedRng()));
if (variate != EnumClass::kEmpty && variate != EnumClass::kDeleted)
return static_cast<EnumClass>(variate);
}
}
};
template <>
struct Generator<std::string> {
std::string operator()() const;
};
template <>
struct Generator<absl::string_view> {
absl::string_view operator()() const;
};
template <>
struct Generator<NonStandardLayout> {
NonStandardLayout operator()() const {
return NonStandardLayout(Generator<std::string>()());
}
};
template <class K, class V>
struct Generator<std::pair<K, V>> {
std::pair<K, V> operator()() const {
return std::pair<K, V>(Generator<typename std::decay<K>::type>()(),
Generator<typename std::decay<V>::type>()());
}
};
template <class... Ts>
struct Generator<std::tuple<Ts...>> {
std::tuple<Ts...> operator()() const {
return std::tuple<Ts...>(Generator<typename std::decay<Ts>::type>()()...);
}
};
template <class T>
struct Generator<std::unique_ptr<T>> {
std::unique_ptr<T> operator()() const {
return absl::make_unique<T>(Generator<T>()());
}
};
template <class U>
struct Generator<U, absl::void_t<decltype(std::declval<U&>().key()),
decltype(std::declval<U&>().value())>>
: Generator<std::pair<
typename std::decay<decltype(std::declval<U&>().key())>::type,
typename std::decay<decltype(std::declval<U&>().value())>::type>> {};
template <class Container>
using GeneratedType = decltype(
std::declval<const Generator<
typename std::conditional<generator_internal::IsMap<Container>::value,
typename Container::value_type,
typename Container::key_type>::type>&>()());
// Naive wrapper that performs a linear search of previous values.
// Beware this is O(SQR), which is reasonable for smaller kMaxValues.
template <class T, size_t kMaxValues = 64, class E = void>
struct UniqueGenerator {
Generator<T, E> gen;
std::vector<T> values;
T operator()() {
assert(values.size() < kMaxValues);
for (;;) {
T value = gen();
if (std::find(values.begin(), values.end(), value) == values.end()) {
values.push_back(value);
return value;
}
}
}
};
} // namespace hash_internal
} // namespace container_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_CONTAINER_INTERNAL_HASH_GENERATOR_TESTING_H_