Resource.cpp

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2008. 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 $(WIND_BASE)/WPILib.  */
/*----------------------------------------------------------------------------*/

#include "Resource.h"
#include "WPIErrors.h"
#include "ErrorBase.h"

Resource *Resource::m_resourceList = NULL;

Resource::Resource(UINT32 elements)
{
        m_size = elements;
        m_isAllocated = new bool[m_size];
        for (UINT32 i=0; i < m_size; i++)
                m_isAllocated[i] = false;
        m_nextResource = m_resourceList;
        m_resourceList = this;
}

/*static*/ void Resource::CreateResourceObject(Resource **r, UINT32 elements)
{
        if (*r == NULL)
                *r = new Resource(elements);
}

Resource::~Resource()
{
        delete[] m_isAllocated;
}

UINT32 Resource::Allocate(const char *resourceDesc)
{
        for (UINT32 i=0; i < m_size; i++)
        {
                if (!m_isAllocated[i])
                {
                        m_isAllocated[i] = true;
                        return i;
                }
        }
        wpi_setWPIErrorWithContext(NoAvailableResources, resourceDesc);
        return ~0ul;
}

UINT32 Resource::Allocate(UINT32 index, const char *resourceDesc)
{
        if (index >= m_size)
        {
                wpi_setWPIErrorWithContext(ChannelIndexOutOfRange, resourceDesc);
                return ~0ul;
        }
        if ( m_isAllocated[index] )
        {
                wpi_setWPIErrorWithContext(ResourceAlreadyAllocated, resourceDesc);
                return ~0ul;
        }
        m_isAllocated[index] = true;
        return index;
}


void Resource::Free(UINT32 index)
{
        if (index == ~0ul) return;
        if (index >= m_size)
        {
                wpi_setWPIError(NotAllocated);
                return;
        }
        if (!m_isAllocated[index])
        {
                wpi_setWPIError(NotAllocated);
                return;
        }
        m_isAllocated[index] = false;
}