Files
allwpilib/hal/include/HAL/handles/UnlimitedHandleResource.h

88 lines
3.2 KiB
C++

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2008-2016. All Rights Reserved. */
/* Open Source Software - may be modified and shared by FRC teams. The code */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project. */
/*----------------------------------------------------------------------------*/
#pragma once
#include <stdint.h>
#include <memory>
#include <vector>
#include "HAL/Types.h"
#include "HAL/cpp/priority_mutex.h"
#include "HAL/handles/HandlesInternal.h"
namespace hal {
/**
* The UnlimitedHandleResource class is a way to track handles. This version
* allows an unlimted number of handles that are allocated sequentially. When
* possible, indices are reused to save memory usage and keep the array length
* down.
* However, automatic array management has not been implemented, but might be in
* the future.
* Because we have to loop through the allocator, we must use a global mutex.
* @tparam THandle The Handle Type (Must be typedefed from HAL_Handle)
* @tparam TStruct The struct type held by this resource
* @tparam enumValue The type value stored in the handle
*
*/
template <typename THandle, typename TStruct, HAL_HandleEnum enumValue>
class UnlimitedHandleResource {
friend class UnlimitedHandleResourceTest;
public:
UnlimitedHandleResource(const UnlimitedHandleResource&) = delete;
UnlimitedHandleResource operator=(const UnlimitedHandleResource&) = delete;
UnlimitedHandleResource() = default;
THandle Allocate(std::shared_ptr<TStruct> structure);
std::shared_ptr<TStruct> Get(THandle handle);
void Free(THandle handle);
private:
std::vector<std::shared_ptr<TStruct>> m_structures;
priority_mutex m_handleMutex;
};
template <typename THandle, typename TStruct, HAL_HandleEnum enumValue>
THandle UnlimitedHandleResource<THandle, TStruct, enumValue>::Allocate(
std::shared_ptr<TStruct> structure) {
std::lock_guard<priority_mutex> sync(m_handleMutex);
size_t i;
for (i = 0; i < m_structures.size(); i++) {
if (m_structures[i] == nullptr) {
m_structures[i] = structure;
return static_cast<THandle>(createHandle(i, enumValue));
}
}
if (i >= INT16_MAX) return HAL_kInvalidHandle;
m_structures.push_back(structure);
return static_cast<THandle>(createHandle(static_cast<int16_t>(i), enumValue));
}
template <typename THandle, typename TStruct, HAL_HandleEnum enumValue>
std::shared_ptr<TStruct>
UnlimitedHandleResource<THandle, TStruct, enumValue>::Get(THandle handle) {
int16_t index = getHandleTypedIndex(handle, enumValue);
std::lock_guard<priority_mutex> sync(m_handleMutex);
if (index < 0 || index >= static_cast<int16_t>(m_structures.size()))
return nullptr;
return m_structures[index];
}
template <typename THandle, typename TStruct, HAL_HandleEnum enumValue>
void UnlimitedHandleResource<THandle, TStruct, enumValue>::Free(
THandle handle) {
int16_t index = getHandleTypedIndex(handle, enumValue);
std::lock_guard<priority_mutex> sync(m_handleMutex);
if (index < 0 || index >= static_cast<int16_t>(m_structures.size())) return;
m_structures[index].reset();
}
} // namespace hal