Adding a number of utilities

LocHeap, LocThread, LocTimer, and moved MsgTask to
utils. Also added are LocRankable and LocRunnable
abstract classes.

Change-Id: I76975455d24f2c84a95dcc1b04f79fea562ea5ba
CRs-Fixed: 855222

1 files changed, 664 insertions, 0 deletions

diff --git a/utils/LocTimer.cpp b/utils/LocTimer.cpp
new file mode 100644
index 0000000..2209809
--- /dev/null
+++ b/utils/LocTimer.cpp
@@ -0,0 +1,664 @@
+/* Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ *       copyright notice, this list of conditions and the following
+ *       disclaimer in the documentation and/or other materials provided
+ *       with the distribution.
+ *     * Neither the name of The Linux Foundation, nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <errno.h>
+#include <loc_timer.h>
+#include <sys/timerfd.h>
+#include <sys/epoll.h>
+#include <LocTimer.h>
+#include <LocHeap.h>
+#include <LocThread.h>
+#include <pthread.h>
+#include <MsgTask.h>
+
+#ifdef __HOST_UNIT_TEST__
+#define EPOLLWAKEUP 0
+#define CLOCK_BOOTTIME CLOCK_MONOTONIC
+#define CLOCK_BOOTTIME_ALARM CLOCK_MONOTONIC
+#endif
+
+using namespace loc_core;
+
+/*
+There are implementations of 5 classes in this file:
+LocTimer, LocTimerDelegate, LocTimerContainer, LocTimerPollTask, LocTimerWrapper
+
+LocTimer - client front end, interface for client to start / stop timers, also
+           to provide a callback.
+LocTimerDelegate - an internal timer entity, which also is a LocRankable obj.
+                   Its life cycle is different than that of LocTimer. It gets
+                   created when LocTimer::start() is called, and gets deleted
+                   when it expires or clients calls the hosting LocTimer obj's
+                   stop() method. When a LocTimerDelegate obj is ticking, it
+                   stays in the corresponding LocTimerContainer. When expired
+                   or stopped, the obj is removed from the container. Since it
+                   is also a LocRankable obj, and LocTimerContainer also is a
+                   heap, its ranks() implementation decides where it is placed
+                   in the heap.
+LocTimerContainer - core of the timer service. It is a container (derived from
+                    LocHeap) for LocTimerDelegate (implements LocRankable) objs.
+                    There are 2 of such containers, one for sw timers (or Linux
+                    timers) one for hw timers (or Linux alarms). It adds one of
+                    each (those that expire the soonest) to kernel via services
+                    provided by LocTimerPollTask. All the heap management on the
+                    LocTimerDelegate objs are done in the MsgTask context, such
+                    that synchronization is ensured.
+LocTimerPollTask - is a class that wraps timerfd and epoll POXIS APIs. It also
+                   both implements LocRunnalbe with epoll_wait() in the run()
+                   method. It is also a LocThread client, so as to loop the run
+                   method.
+LocTimerWrapper - a LocTimer client itself, to implement the existing C API with
+                  APIs, loc_timer_start() and loc_timer_stop().
+
+*/
+
+class LocTimerPollTask;
+
+// This is a multi-functaional class that:
+// * extends the LocHeap class for the detection of head update upon add / remove
+//   events. When that happens, soonest time out changes, so timerfd needs update.
+// * contains the timers, and add / remove them into the heap
+// * provides and maps 2 of such containers, one for timers (or  mSwTimers), one
+//   for alarms (or mHwTimers);
+// * provides a polling thread;
+// * provides a MsgTask thread for synchronized add / remove / timer client callback.
+class LocTimerContainer : public LocHeap {
+    // mutex to synchronize getters of static members
+    static pthread_mutex_t mMutex;
+    // Container of timers
+    static LocTimerContainer* mSwTimers;
+    // Container of alarms
+    static LocTimerContainer* mHwTimers;
+    // Msg task to provider msg Q, sender and reader.
+    static MsgTask* mMsgTask;
+    // Poll task to provide epoll call and threading to poll.
+    static LocTimerPollTask* mPollTask;
+    // timer / alarm fd
+    const int mDevFd;
+    // ctor
+    LocTimerContainer(bool wakeOnExpire);
+    // dtor
+    ~LocTimerContainer();
+    static MsgTask* getMsgTaskLocked();
+    static LocTimerPollTask* getPollTaskLocked();
+    // extend LocHeap and pop if the top outRanks input
+    LocTimerDelegate* popIfOutRanks(LocTimerDelegate& timer);
+
+public:
+    // factory method to control the creation of mSwTimers / mHwTimers
+    static LocTimerContainer* get(bool wakeOnExpire);
+
+    LocTimerDelegate* getSoonestTimer();
+    int getTimerFd();
+    // add a timer / alarm obj into the container
+    void add(LocTimerDelegate& timer);
+    // remove a timer / alarm obj from the container
+    void remove(LocTimerDelegate& timer);
+    // handling of timer / alarm expiration
+    void expire();
+};
+
+// This class implements the polling thread that epolls imer / alarm fds.
+// The LocRunnable::run() contains the actual polling.  The other methods
+// will be run in the caller's thread context to add / remove timer / alarm
+// fds the kernel, while the polling is blocked on epoll_wait() call.
+// Since the design is that we have maximally 2 polls, one for all the
+// timers; one for all the alarms, we will poll at most on 2 fds.  But it
+// is possile that all we have are only timers or alarms at one time, so we
+// allow dynamically add / remove fds we poll on. The design decision of
+// having 1 fd per container of timer / alarm is such that, we may not need
+// to make a system call each time a timer / alarm is added / removed, unless
+// that changes the "soonest" time out of that of all the timers / alarms.
+class LocTimerPollTask : public LocRunnable {
+    // the epoll fd
+    const int mFd;
+    // the thread that calls run() method
+    LocThread* mThread;
+    friend class LocThreadDelegate;
+    // dtor
+    ~LocTimerPollTask();
+public:
+    // ctor
+    LocTimerPollTask();
+    // this obj will be deleted once thread is deleted
+    void destroy();
+    // add a container of timers. Each contain has a unique device fd, i.e.
+    // either timer or alarm fd, and a heap of timers / alarms. It is expected
+    // that container would have written to the device fd with the soonest
+    // time out value in the heap at the time of calling this method. So all
+    // this method does is to add the fd of the input container to the poll
+    // and also add the pointer of the container to the event data ptr, such
+    // when poll_wait wakes up on events, we know who is the owner of the fd.
+    void addPoll(LocTimerContainer& timerContainer);
+    // remove a fd that is assciated with a container. The expectation is that
+    // the atual timer would have been removed from the container.
+    void removePoll(LocTimerContainer& timerContainer);
+    // The polling thread context will call this method. This is where
+    // epoll_wait() is blocking and waiting for events..
+    virtual bool run();
+};
+
+// Internal class of timer obj. It gets born when client calls LocTimer::start();
+// and gets deleted when client calls LocTimer::stop() or when the it expire()'s.
+// This class implements LocRankable::ranks() so that when an obj is added into
+// the container (of LocHeap), it gets placed in sorted order.
+class LocTimerDelegate : public LocRankable {
+    friend class LocTimerContainer;
+    friend class LocTimer;
+    LocTimer* mClient;
+    struct timespec mFutureTime;
+    LocTimerContainer* mContainer;
+    // not a complete obj, just ctor for LocRankable comparisons
+    inline LocTimerDelegate(struct timespec& delay)
+        : mClient(NULL), mFutureTime(delay), mContainer(NULL) {}
+    inline ~LocTimerDelegate() {}
+public:
+    LocTimerDelegate(LocTimer& client, struct timespec& futureTime, bool wakeOnExpire);
+    void destroy();
+    // LocRankable virtual method
+    virtual int ranks(LocRankable& rankable);
+    void expire();
+    inline struct timespec getFutureTime() { return mFutureTime; }
+};
+
+/***************************LocTimerContainer methods***************************/
+
+// Most of these static recources are created on demand. They however are never
+// destoyed. The theory is that there are processes that link to this util lib
+// but never use timer, then these resources would never need to be created.
+// For those processes that do use timer, it will likely also need to every
+// once in a while. It might be cheaper keeping them around.
+pthread_mutex_t LocTimerContainer::mMutex = PTHREAD_MUTEX_INITIALIZER;
+LocTimerContainer* LocTimerContainer::mSwTimers = NULL;
+LocTimerContainer* LocTimerContainer::mHwTimers = NULL;
+MsgTask* LocTimerContainer::mMsgTask = NULL;
+LocTimerPollTask* LocTimerContainer::mPollTask = NULL;
+
+// ctor - initialize timer heaps
+// A container for swTimer (timer) is created, when wakeOnExpire is true; or
+// HwTimer (alarm), when wakeOnExpire is false.
+LocTimerContainer::LocTimerContainer(bool wakeOnExpire) :
+    mDevFd(timerfd_create(wakeOnExpire ? CLOCK_BOOTTIME_ALARM : CLOCK_BOOTTIME, 0)) {
+    if (-1 != mDevFd) {
+        // ensure we have the necessary resources created
+        LocTimerContainer::getPollTaskLocked();
+        LocTimerContainer::getMsgTaskLocked();
+    } else {
+        LOC_LOGE("%s: timerfd_create failure - %s", __FUNCTION__, strerror(errno));
+    }
+}
+
+// dtor
+// we do not ever destroy the static resources.
+inline
+LocTimerContainer::~LocTimerContainer() {
+    close(mDevFd);
+}
+
+LocTimerContainer* LocTimerContainer::get(bool wakeOnExpire) {
+    // get the reference of either mHwTimer or mSwTimers per wakeOnExpire
+    LocTimerContainer*& container = wakeOnExpire ? mHwTimers : mSwTimers;
+    // it is cheap to check pointer first than locking mutext unconditionally
+    if (!container) {
+        pthread_mutex_lock(&mMutex);
+        // let's check one more time to be safe
+        if (!container) {
+            container = new LocTimerContainer(wakeOnExpire);
+            // timerfd_create failure
+            if (-1 == container->getTimerFd()) {
+                delete container;
+                container = NULL;
+            }
+        }
+        pthread_mutex_unlock(&mMutex);
+    }
+    return container;
+}
+
+MsgTask* LocTimerContainer::getMsgTaskLocked() {
+    // it is cheap to check pointer first than locking mutext unconditionally
+    if (!mMsgTask) {
+        mMsgTask = new MsgTask("LocTimerMsgTask", false);
+    }
+    return mMsgTask;
+}
+
+LocTimerPollTask* LocTimerContainer::getPollTaskLocked() {
+    // it is cheap to check pointer first than locking mutext unconditionally
+    if (!mPollTask) {
+        mPollTask = new LocTimerPollTask();
+    }
+    return mPollTask;
+}
+
+inline
+LocTimerDelegate* LocTimerContainer::getSoonestTimer() {
+    return (LocTimerDelegate*)(peek());
+}
+
+inline
+int LocTimerContainer::getTimerFd() {
+    return mDevFd;
+}
+
+// all the heap management is done in the MsgTask context.
+inline
+void LocTimerContainer::add(LocTimerDelegate& timer) {
+    struct MsgTimerPush : public LocMsg {
+        LocTimerContainer* mTimerContainer;
+        LocHeapNode* mTree;
+        LocTimerPollTask* mPollTask;
+        LocTimerDelegate* mTimer;
+        inline MsgTimerPush(LocTimerContainer& container, LocTimerPollTask& pollTask, LocTimerDelegate& timer) :
+            LocMsg(), mTimerContainer(&container), mPollTask(&pollTask), mTimer(&timer) {}
+        inline virtual void proc() const {
+            LocTimerDelegate* priorTop = mTimerContainer->getSoonestTimer();
+            mTimerContainer->push((LocRankable&)(*mTimer));
+
+            // if the tree top changed (new top is the new node), we need to update
+            // timerfd with the new timerout value.
+            if (priorTop != mTimerContainer->getSoonestTimer()) {
+                // if tree was empty before, we need to let poll task poll on this
+                // do this first to avoid race condition, in case settime is called
+                // with too small an interval
+                if (!priorTop) {
+                    mPollTask->addPoll(*mTimerContainer);
+                }
+                struct itimerspec delay = {0};
+                delay.it_value = mTimer->getFutureTime();
+                timerfd_settime(mTimerContainer->getTimerFd(), TFD_TIMER_ABSTIME, &delay, NULL);
+            }
+        }
+    };
+
+    mMsgTask->sendMsg(new MsgTimerPush(*this, *mPollTask, timer));
+}
+
+// all the heap management is done in the MsgTask context.
+void LocTimerContainer::remove(LocTimerDelegate& timer) {
+    struct MsgTimerRemove : public LocMsg {
+        LocTimerContainer* mTimerContainer;
+        LocTimerPollTask* mPollTask;
+        LocTimerDelegate* mTimer;
+        inline MsgTimerRemove(LocTimerContainer& container, LocTimerPollTask& pollTask, LocTimerDelegate& timer) :
+            LocMsg(), mTimerContainer(&container), mPollTask(&pollTask), mTimer(&timer) {}
+        inline virtual void proc() const {
+            LocTimerDelegate* priorTop = mTimerContainer->getSoonestTimer();
+            ((LocHeap*)mTimerContainer)->remove((LocRankable&)*mTimer);
+            delete mTimer;
+            LocTimerDelegate* curTop = mTimerContainer->getSoonestTimer();
+
+            // if the tree top changed (the removed the node was the tree top), we need
+            // to update the timerfd with the new timeout value from the new top.
+            if (priorTop != curTop) {
+                struct itimerspec delay = {0};
+                // if tree is empty now, we need to remove poll from poll task
+                if (!curTop) {
+                    mPollTask->removePoll(*mTimerContainer);
+                    // setting the values to disarm timer
+                    delay.it_value.tv_sec = 0;
+                    delay.it_value.tv_nsec = 0;
+                } else {
+                    delay.it_value = curTop->getFutureTime();
+                }
+                // this will either update the timer with the new soonest timeout
+                // or disarm the timer, if the current tree top empty
+                timerfd_settime(mTimerContainer->getTimerFd(), TFD_TIMER_ABSTIME, &delay, NULL);
+            }
+        }
+    };
+
+    mMsgTask->sendMsg(new MsgTimerRemove(*this, *mPollTask, timer));
+}
+
+// all the heap management is done in the MsgTask context.
+// Upon expire, we check and continuously pop the heap until
+// the top node's timeout is in the future.
+void LocTimerContainer::expire() {
+    struct MsgTimerExpire : public LocMsg {
+        LocTimerContainer* mTimerContainer;
+        inline MsgTimerExpire(LocTimerContainer& container) :
+            LocMsg(), mTimerContainer(&container) {}
+        inline virtual void proc() const {
+            struct timespec now;
+            // get time spec of now
+            clock_gettime(CLOCK_BOOTTIME, &now);
+            LocTimerDelegate timerOfNow(now);
+            // pop everything in the heap that outRanks now, i.e. has time older than now
+            // and then call expire() on that timer.
+            for (LocTimerDelegate* timer = mTimerContainer->popIfOutRanks(timerOfNow);
+                 NULL != timer;
+                 timer = mTimerContainer->popIfOutRanks(timerOfNow)) {
+                // the timer delegate obj will be deleted before the return of this call
+                timer->expire();
+            }
+        }
+    };
+
+    mMsgTask->sendMsg(new MsgTimerExpire(*this));
+}
+
+LocTimerDelegate* LocTimerContainer::popIfOutRanks(LocTimerDelegate& timer) {
+    LocTimerDelegate* poppedNode = NULL;
+
+    if (mTree && peek()->outRanks((LocRankable&)(timer))) {
+        poppedNode = (LocTimerDelegate*)(pop());
+    }
+
+    return poppedNode;
+}
+
+
+/***************************LocTimerPollTask methods***************************/
+
+inline
+LocTimerPollTask::LocTimerPollTask()
+    : mFd(epoll_create(2)), mThread(new LocThread()) {
+    // before a next call returens, a thread will be created. The run() method
+    // could already be running in parallel. Also, since each of the objs
+    // creates a thread, the container will make sure that there will be only
+    // one of such obj for our timer implementation.
+    if (!mThread->start("LocTimerPollTask", this)) {
+        delete mThread;
+        mThread = NULL;
+    }
+}
+
+inline
+LocTimerPollTask::~LocTimerPollTask() {
+    // when fs is closed, epoll_wait() should fail run() should return false
+    // and the spawned thread should exit.
+    close(mFd);
+}
+
+void LocTimerPollTask::destroy() {
+    if (mThread) {
+        LocThread* thread = mThread;
+        mThread = NULL;
+        delete thread;
+    } else {
+        delete this;
+    }
+}
+
+void LocTimerPollTask::addPoll(LocTimerContainer& timerContainer) {
+    struct epoll_event ev;
+    memset(&ev, 0, sizeof(ev));
+
+    ev.events = EPOLLIN | EPOLLWAKEUP;
+    // it is important that we set this context pointer with the input
+    // timer container this is how we know which container should handle
+    // which expiration.
+    ev.data.ptr = &timerContainer;
+    epoll_ctl(mFd, EPOLL_CTL_ADD, timerContainer.getTimerFd(), &ev);
+}
+
+inline
+void LocTimerPollTask::removePoll(LocTimerContainer& timerContainer) {
+    epoll_ctl(mFd, EPOLL_CTL_DEL, timerContainer.getTimerFd(), NULL);
+}
+
+// The polling thread context will call this method. If run() method needs to
+// be repetitvely called, it must return true from the previous call.
+bool LocTimerPollTask::run() {
+    struct epoll_event ev[2];
+    // we have max 2 descriptors to poll from
+    int fds = epoll_wait(mFd, ev, 2, -1);
+    // we pretty much want to continually poll until the fd is closed
+    bool rerun = (fds > 0) || (errno == EINTR);
+    if (fds > 0) {
+        // we may have 2 events
+        for (int i = 0; i < fds; i++) {
+            // each fd will has a context pointer associated with the right timer container
+            LocTimerContainer* container = (LocTimerContainer*)(ev[i].data.ptr);
+            if (container) {
+                container->expire();
+            }
+        }
+    }
+
+    // if rerun is true, we are requesting to be scheduled again
+    return rerun;
+}
+
+/***************************LocTimerDelegate methods***************************/
+
+inline
+LocTimerDelegate::LocTimerDelegate(LocTimer& client, struct timespec& futureTime, bool wakeOnExpire)
+    : mClient(&client), mFutureTime(futureTime), mContainer(LocTimerContainer::get(wakeOnExpire)) {
+    // adding the timer into the container
+    mContainer->add(*this);
+}
+
+inline
+void LocTimerDelegate::destroy() {
+    if (mContainer) {
+        mContainer->remove(*this);
+        mContainer = NULL;
+    }
+}
+
+int LocTimerDelegate::ranks(LocRankable& rankable) {
+    int rank = -1;
+    LocTimerDelegate* timer = (LocTimerDelegate*)(&rankable);
+    if (timer) {
+        // larger time ranks lower!!!
+        // IOW, if input obj has bigger tv_sec, this obj outRanks higher
+        rank = timer->mFutureTime.tv_sec - mFutureTime.tv_sec;
+    }
+    return rank;
+}
+
+inline
+void LocTimerDelegate::expire() {
+    // keeping a copy of client pointer to be safe
+    // when timeOutCallback() is called at the end of this
+    // method, this obj is already deleted.
+    LocTimer* client = mClient;
+    // this obj is already removed from mContainer.
+    // NULL it here so that dtor won't try to call remove again
+    mContainer = NULL;
+    // force a stop, which will force a delete of this obj
+    mClient->stop();
+    // calling client callback with a pointer save on the stack
+    client->timeOutCallback();
+}
+
+
+/***************************LocTimer methods***************************/
+
+bool LocTimer::start(unsigned int timeOutInMs, bool wakeOnExpire) {
+    bool success = false;
+    if (!mTimer) {
+        struct timespec futureTime;
+        clock_gettime(CLOCK_BOOTTIME, &futureTime);
+        futureTime.tv_sec += timeOutInMs / 1000;
+        futureTime.tv_nsec += (timeOutInMs % 1000) * 1000000;
+        if (futureTime.tv_nsec >= 1000000000) {
+            futureTime.tv_sec += futureTime.tv_nsec / 1000000000;
+            futureTime.tv_nsec %= 1000000000;
+        }
+        mTimer = new LocTimerDelegate(*this, futureTime, wakeOnExpire);
+        // if mTimer is non 0, success should be 0; or vice versa
+        success = (NULL != mTimer);
+    }
+    return success;
+}
+
+bool LocTimer::stop() {
+    bool success = false;
+    if (mTimer) {
+        mTimer->destroy();
+        mTimer = NULL;
+        success = true;
+    }
+    return success;
+}
+
+/***************************LocTimerWrapper methods***************************/
+//////////////////////////////////////////////////////////////////////////
+// This section below wraps for the C style APIs
+//////////////////////////////////////////////////////////////////////////
+class LocTimerWrapper : public LocTimer {
+    loc_timer_callback mCb;
+    void* mCallerData;
+public:
+    inline LocTimerWrapper(loc_timer_callback cb, void* callerData) :
+        mCb(cb), mCallerData(callerData) {}
+    inline virtual void timeOutCallback() { mCb(mCallerData, 0); }
+};
+
+void* loc_timer_start(uint64_t msec, loc_timer_callback cb_func,
+                      void *caller_data, bool wake_on_expire)
+{
+    LocTimerWrapper* locTimerWrapper = new LocTimerWrapper(cb_func, caller_data);
+
+    if (locTimerWrapper) {
+        locTimerWrapper->start(msec, wake_on_expire);
+    }
+
+    return locTimerWrapper;
+}
+
+void loc_timer_stop(void*&  handle)
+{
+    if (handle) {
+        LocTimerWrapper* locTimerWrapper = (LocTimerWrapper*)(handle);
+        locTimerWrapper->stop();
+        delete locTimerWrapper;
+        handle = NULL;
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+// This section above wraps for the C style APIs
+//////////////////////////////////////////////////////////////////////////
+
+#ifdef __LOC_DEBUG__
+
+double getDeltaSeconds(struct timespec from, struct timespec to) {
+    return (double)to.tv_sec + (double)to.tv_nsec / 1000000000
+        - from.tv_sec - (double)from.tv_nsec / 1000000000;
+}
+
+struct timespec getNow() {
+    struct timespec now;
+    clock_gettime(CLOCK_BOOTTIME, &now);
+    return now;
+}
+
+class LocTimerTest : public LocTimer, public LocRankable {
+    int mTimeOut;
+    const struct timespec mTimeOfBirth;
+    inline struct timespec getTimerWrapper(int timeout) {
+        struct timespec now;
+        clock_gettime(CLOCK_BOOTTIME, &now);
+        now.tv_sec += timeout;
+        return now;
+    }
+public:
+    inline LocTimerTest(int timeout) : LocTimer(), LocRankable(),
+            mTimeOut(timeout), mTimeOfBirth(getTimerWrapper(0)) {}
+    inline virtual int ranks(LocRankable& rankable) {
+        LocTimerTest* timer = dynamic_cast<LocTimerTest*>(&rankable);
+        return timer->mTimeOut - mTimeOut;
+    }
+    inline virtual void timeOutCallback() {
+        printf("timeOutCallback() - ");
+        deviation();
+    }
+    double deviation() {
+        struct timespec now = getTimerWrapper(0);
+        double delta = getDeltaSeconds(mTimeOfBirth, now);
+        printf("%lf: %lf\n", delta, delta * 100 / mTimeOut);
+        return delta / mTimeOut;
+    }
+};
+
+// For Linux command line testing:
+// compilation:
+//     g++ -D__LOC_HOST_DEBUG__ -D__LOC_DEBUG__ -g -I. -I../../../../system/core/include -o LocHeap.o LocHeap.cpp
+//     g++ -D__LOC_HOST_DEBUG__ -D__LOC_DEBUG__ -g -std=c++0x -I. -I../../../../system/core/include -lpthread -o LocThread.o LocThread.cpp
+//     g++ -D__LOC_HOST_DEBUG__ -D__LOC_DEBUG__ -g -I. -I../../../../system/core/include -o LocTimer.o LocTimer.cpp
+int main(int argc, char** argv) {
+    struct timespec timeOfStart=getNow();
+    srand(time(NULL));
+    int tries = atoi(argv[1]);
+    int checks = tries >> 3;
+    LocTimerTest** timerArray = new LocTimerTest*[tries];
+    memset(timerArray, NULL, tries);
+
+    for (int i = 0; i < tries; i++) {
+        int r = rand() % tries;
+        LocTimerTest* timer = new LocTimerTest(r);
+        if (timerArray[r]) {
+            if (!timer->stop()) {
+                printf("%lf:\n", getDeltaSeconds(timeOfStart, getNow()));
+                printf("ERRER: %dth timer, id %d, not running when it should be\n", i, r);
+                exit(0);
+            } else {
+                printf("stop() - %d\n", r);
+                delete timer;
+                timerArray[r] = NULL;
+            }
+        } else {
+            if (!timer->start(r, false)) {
+                printf("%lf:\n", getDeltaSeconds(timeOfStart, getNow()));
+                printf("ERRER: %dth timer, id %d, running when it should not be\n", i, r);
+                exit(0);
+            } else {
+                printf("stop() - %d\n", r);
+                timerArray[r] = timer;
+            }
+        }
+    }
+
+    for (int i = 0; i < tries; i++) {
+        if (timerArray[i]) {
+            if (!timerArray[i]->stop()) {
+                printf("%lf:\n", getDeltaSeconds(timeOfStart, getNow()));
+                printf("ERRER: %dth timer, not running when it should be\n", i);
+                exit(0);
+            } else {
+                printf("stop() - %d\n", i);
+                delete timerArray[i];
+                timerArray[i] = NULL;
+            }
+        }
+    }
+
+    delete[] timerArray;
+
+    return 0;
+}
+
+#endif