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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// 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.
// Contains utilities for making UBSan happy.
#pragma once
#include <cstring>
#include <memory>
#include <type_traits>
#include "arrow/util/macros.h"
namespace arrow {
namespace util {
namespace internal {
static uint8_t non_null_filler;
} // namespace internal
/// \brief Returns maybe_null if not null or a non-null pointer to an arbitrary memory
/// that shouldn't be dereferenced.
///
/// Memset/Memcpy are undefined when a nullptr is passed as an argument use this utility
/// method to wrap locations where this could happen.
///
/// Note: Flatbuffers has UBSan warnings if a zero length vector is passed.
/// https://github.com/google/flatbuffers/pull/5355 is trying to resolve
/// them.
template <typename T>
inline T* MakeNonNull(T* maybe_null) {
if (ARROW_PREDICT_TRUE(maybe_null != NULLPTR)) {
return maybe_null;
}
return reinterpret_cast<T*>(&internal::non_null_filler);
}
template <typename T>
inline typename std::enable_if<std::is_trivial<T>::value, T>::type SafeLoadAs(
const uint8_t* unaligned) {
typename std::remove_const<T>::type ret;
std::memcpy(&ret, unaligned, sizeof(T));
return ret;
}
template <typename T>
inline typename std::enable_if<std::is_trivial<T>::value, T>::type SafeLoad(
const T* unaligned) {
typename std::remove_const<T>::type ret;
std::memcpy(&ret, unaligned, sizeof(T));
return ret;
}
template <typename U, typename T>
inline typename std::enable_if<std::is_trivial<T>::value && std::is_trivial<U>::value &&
sizeof(T) == sizeof(U),
U>::type
SafeCopy(T value) {
typename std::remove_const<U>::type ret;
std::memcpy(&ret, &value, sizeof(T));
return ret;
}
template <typename T>
inline typename std::enable_if<std::is_trivial<T>::value, void>::type SafeStore(
void* unaligned, T value) {
std::memcpy(unaligned, &value, sizeof(T));
}
} // namespace util
} // namespace arrow
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