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/**
* Copyright (C) 2023 The Android Open Source Project
*
* 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
*
* 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.
*/
#pragma once
#include <cstdlib>
#include <memory>
#include <type_traits>
namespace android {
namespace uirenderer {
/** Manages an array of T elements, freeing the array in the destructor.
* Does NOT call any constructors/destructors on T (T must be POD).
*/
template <typename T,
typename = std::enable_if_t<std::is_trivially_default_constructible<T>::value &&
std::is_trivially_destructible<T>::value>>
class AutoTMalloc {
public:
/** Takes ownership of the ptr. The ptr must be a value which can be passed to std::free. */
explicit AutoTMalloc(T* ptr = nullptr) : fPtr(ptr) {}
/** Allocates space for 'count' Ts. */
explicit AutoTMalloc(size_t count) : fPtr(mallocIfCountThrowOnFail(count)) {}
AutoTMalloc(AutoTMalloc&&) = default;
AutoTMalloc& operator=(AutoTMalloc&&) = default;
/** Resize the memory area pointed to by the current ptr preserving contents. */
void realloc(size_t count) { fPtr.reset(reallocIfCountThrowOnFail(count)); }
/** Resize the memory area pointed to by the current ptr without preserving contents. */
T* reset(size_t count = 0) {
fPtr.reset(mallocIfCountThrowOnFail(count));
return this->get();
}
T* get() const { return fPtr.get(); }
operator T*() { return fPtr.get(); }
operator const T*() const { return fPtr.get(); }
T& operator[](int index) { return fPtr.get()[index]; }
const T& operator[](int index) const { return fPtr.get()[index]; }
/**
* Transfer ownership of the ptr to the caller, setting the internal
* pointer to NULL. Note that this differs from get(), which also returns
* the pointer, but it does not transfer ownership.
*/
T* release() { return fPtr.release(); }
private:
struct FreeDeleter {
void operator()(uint8_t* p) { std::free(p); }
};
std::unique_ptr<T, FreeDeleter> fPtr;
T* mallocIfCountThrowOnFail(size_t count) {
T* newPtr = nullptr;
if (count) {
newPtr = (T*)std::malloc(count * sizeof(T));
LOG_ALWAYS_FATAL_IF(!newPtr, "failed to malloc %zu bytes", count * sizeof(T));
}
return newPtr;
}
T* reallocIfCountThrowOnFail(size_t count) {
T* newPtr = nullptr;
if (count) {
newPtr = (T*)std::realloc(fPtr.release(), count * sizeof(T));
LOG_ALWAYS_FATAL_IF(!newPtr, "failed to realloc %zu bytes", count * sizeof(T));
}
return newPtr;
}
};
} // namespace uirenderer
} // namespace android
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