Files
allwpilib/hal/lib/athena/cpp/Resource.cpp
Peter Mitrano e71f454b9d Renamed folders for consistency, using sim/athena/shared schema (#27)
Rename the following folders:
hal/lib/Athena -> hal/lib/athena
hal/lib/Desktop -> hal/lib/sim
hal/lib/Shared -> hal/lib/shared
wpilibc/Athena -> wpilibc/athena
wpilibc/simulation -> wpilibc/sim

Windows users may need to run gradlew clean after updating.
2016-05-22 14:55:51 -07:00

104 lines
3.5 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. */
/*----------------------------------------------------------------------------*/
#include "HAL/cpp/Resource.hpp"
#include <cstddef>
#include "HAL/Errors.hpp"
#include "HAL/cpp/priority_mutex.h"
namespace hal {
priority_recursive_mutex Resource::m_createLock;
/**
* Allocate storage for a new instance of Resource.
* Allocate a bool array of values that will get initialized to indicate that no
* resources have been allocated yet. The indicies of the resources are [0 ..
* elements - 1].
*/
Resource::Resource(uint32_t elements) {
std::lock_guard<priority_recursive_mutex> sync(m_createLock);
m_isAllocated = std::vector<bool>(elements, false);
}
/**
* Factory method to create a Resource allocation-tracker *if* needed.
*
* @param r -- address of the caller's Resource pointer. If *r == NULL, this
* will construct a Resource and make *r point to it. If *r != NULL, i.e.
* the caller already has a Resource instance, this won't do anything.
* @param elements -- the number of elements for this Resource allocator to
* track, that is, it will allocate resource numbers in the range
* [0 .. elements - 1].
*/
/*static*/ void Resource::CreateResourceObject(Resource** r,
uint32_t elements) {
std::lock_guard<priority_recursive_mutex> sync(m_createLock);
if (*r == NULL) {
*r = new Resource(elements);
}
}
/**
* Allocate a resource.
* When a resource is requested, mark it allocated. In this case, a free
* resource value
* within the range is located and returned after it is marked allocated.
*/
uint32_t Resource::Allocate(const char* resourceDesc) {
std::lock_guard<priority_recursive_mutex> sync(m_allocateLock);
for (uint32_t i = 0; i < m_isAllocated.size(); i++) {
if (!m_isAllocated[i]) {
m_isAllocated[i] = true;
return i;
}
}
// TODO: wpi_setWPIErrorWithContext(NoAvailableResources, resourceDesc);
return ~0ul;
}
/**
* Allocate a specific resource value.
* The user requests a specific resource value, i.e. channel number and it is
* verified unallocated, then returned.
*/
uint32_t Resource::Allocate(uint32_t index, const char* resourceDesc) {
std::lock_guard<priority_recursive_mutex> sync(m_allocateLock);
if (index >= m_isAllocated.size()) {
// TODO: wpi_setWPIErrorWithContext(ChannelIndexOutOfRange, resourceDesc);
return ~0ul;
}
if (m_isAllocated[index]) {
// TODO: wpi_setWPIErrorWithContext(ResourceAlreadyAllocated, resourceDesc);
return ~0ul;
}
m_isAllocated[index] = true;
return index;
}
/**
* Free an allocated resource.
* After a resource is no longer needed, for example a destructor is called for
* a channel assignment class, Free will release the resource value so it can
* be reused somewhere else in the program.
*/
void Resource::Free(uint32_t index) {
std::lock_guard<priority_recursive_mutex> sync(m_allocateLock);
if (index == ~0ul) return;
if (index >= m_isAllocated.size()) {
// TODO: wpi_setWPIError(NotAllocated);
return;
}
if (!m_isAllocated[index]) {
// TODO: wpi_setWPIError(NotAllocated);
return;
}
m_isAllocated[index] = false;
}
} // namespace hal