/*
 * MultiThreading.cpp
 *****************************************************************************
 * Copyright (C) 2012, bitmovin Softwareentwicklung OG, All Rights Reserved
 *
 * Email: libdash-dev@vicky.bitmovin.net
 *
 * This source code and its use and distribution, is subject to the terms
 * and conditions of the applicable license agreement.
 *****************************************************************************/

#include "MultiThreading.h"

THREAD_HANDLE createThreadPortable(void *(*start_routine) (void *), void *arg)
{
#if defined _WIN32 || defined _WIN64
    return CreateThread (0, 0, (LPTHREAD_START_ROUTINE)start_routine, (LPVOID)arg, 0, 0);
#else
    THREAD_HANDLE th = (THREAD_HANDLE)malloc(sizeof(pthread_t));
    if (!th)
    {
        std::cerr << "Error allocating thread." << std::endl;
        return NULL;
    }

    if(int err = pthread_create(th, NULL, start_routine, arg))
    {
        std::cerr << strerror(err) << std::endl;
        return NULL;
    }
    return th;
#endif
}
void destroyThreadPortable(THREAD_HANDLE th)
{
#if !defined _WIN32 && !defined _WIN64
    if(th)
        free(th);
#else
    CloseHandle(th);
#endif
}

/****************************************************************************
* Condition variables for Windows XP and older windows sytems
*****************************************************************************/
#if defined WINXPOROLDER
void InitCondition       (condition_variable_t *cv)
{
    InitializeCriticalSection(&cv->waitersCountLock);

    cv->waitersCount        = 0;
    cv->waitGenerationCount = 0;
    cv->releaseCount        = 0;

    cv->waitingEvent = CreateEvent (NULL,  // no security
                                    TRUE,  // manual-reset
                                    FALSE, // non-signaled initially
                                    NULL); // unnamed
}
void WaitCondition       (condition_variable_t *cv, CRITICAL_SECTION *externalMutex)
{
    EnterCriticalSection(&cv->waitersCountLock);

    cv->waitersCount++;

    int currentGenerationCount = cv->waitGenerationCount;

    LeaveCriticalSection(&cv->waitersCountLock);
    LeaveCriticalSection(externalMutex);

    bool isWaitDone = false;
    while(!isWaitDone)
    {
        WaitForSingleObject (cv->waitingEvent, INFINITE);
        EnterCriticalSection (&cv->waitersCountLock);

        isWaitDone = (cv->releaseCount > 0 && cv->waitGenerationCount != currentGenerationCount);
        LeaveCriticalSection (&cv->waitersCountLock);
    }

    EnterCriticalSection(externalMutex);
    EnterCriticalSection(&cv->waitersCountLock);

    cv->waitersCount--;
    cv->releaseCount--;
    bool isLastWaiter = (cv->releaseCount == 0);

    LeaveCriticalSection(&cv->waitersCountLock);

    if(isLastWaiter)
        ResetEvent(cv->waitingEvent);
}
void SignalCondition     (condition_variable_t *cv)
{
    EnterCriticalSection(&cv->waitersCountLock);

    if(cv->waitersCount > cv->releaseCount)
    {
        SetEvent(cv->waitingEvent);
        cv->releaseCount++;
        cv->waitGenerationCount++;
    }

    LeaveCriticalSection(&cv->waitersCountLock);
}
void BroadcastCondition  (condition_variable_t *cv)
{
    EnterCriticalSection(&cv->waitersCountLock);

    if(cv->waitersCount > 0)
    {
        SetEvent(cv->waitingEvent);
        cv->releaseCount = cv->waitersCount;
        cv->waitGenerationCount++;
    }

    LeaveCriticalSection(&cv->waitersCountLock);
}
#endif