/*******************************************************************************

 Copyright (c) 2009, Charles McGarvey
 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.
 
 THIS  SOFTWARE  IS  PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 AND  ANY  EXPRESS  OR  IMPLIED  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED.  IN  NO EVENT SHALL THE COPYRIGHT HOLDER 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.

*******************************************************************************/

#ifndef _THREAD_HH_
#define _THREAD_HH_

/**
 * @file thread.hh
 * Light C++ wrapper around SDL threads.
 */

#include <boost/function.hpp>
#include <SDL/SDL.h>


namespace dc {
namespace thread {

//
// The detach function detaches a separate thread by calling 'func' with
// the 'arg' parameter.
//

typedef SDL_Thread* thread;

typedef boost::function<int(void)> function;


int detach_(void* arg)
{
	function func = *(function*)arg;
	int ret = func();

	delete (function*)arg;
	return ret;
}

thread detach(const function& func)
{
	thread t;
	function* fcopy = new function(func);

	t = SDL_CreateThread(detach_, (void*)fcopy);
    if (t == 0) delete fcopy;
	return t;
}


int wait(thread t)
{
	int i;
	SDL_WaitThread(t, &i);
	return i;
}

void kill(thread t)
{
	SDL_KillThread(t);
}


//
// The identifier function returns a unique integer for the calling thread.
//

unsigned int identifier()
{
    return SDL_ThreadID();
}

unsigned int identifier(thread t)
{
    return SDL_GetThreadID(t);
}


// =============================================================================

class mutex
{
    friend class condition;

public:
    mutex() { mutex_ = SDL_CreateMutex(); }
    ~mutex() { SDL_DestroyMutex(mutex_); }

    bool acquireLock() { return (SDL_LockMutex(mutex_)   == 0); }
    bool releaseLock() { return (SDL_UnlockMutex(mutex_) == 0); }

    class lock
    {
        friend class condition;

    public:
        lock(mutex& m) { mutex_ = &m; isLocked_ = false; }
        ~lock() { if (isLocked_) release(); }

        bool acquire() { return (isLocked_ = mutex_->acquireLock()); }
        bool release() { return mutex_->releaseLock(); isLocked_ = false; }
        bool isLocked() const { return isLocked_; }

    protected:
        mutex* mutex_;
        bool isLocked_;
    };

    class scoped_lock : public lock
    {
        public:
            scoped_lock(mutex& m) : lock(m) { acquire(); }
    };

private:
    SDL_mutex* mutex_;
};

// =============================================================================

class condition
{
public:
    condition() { condition_ = SDL_CreateCond(); }
    ~condition() { SDL_DestroyCond(condition_); }

    bool wait(mutex::lock& l)
	{
        return (SDL_CondWait(condition_, l.mutex_->mutex_) == 0);
    }
    bool wait(mutex::lock& l, unsigned ms)
	{
		// TODO: For consistency, this function should take seconds, not ms.
        return (SDL_CondWaitTimeout(condition_, l.mutex_->mutex_, ms) == 0);
	}

    bool notify()    { return (SDL_CondSignal(condition_)    == 0); }
    bool notifyAll() { return (SDL_CondBroadcast(condition_) == 0); }

private:
    SDL_cond* condition_;
};

// =============================================================================

class semaphore
{
public:
    semaphore(unsigned int value) { semaphore_ = SDL_CreateSemaphore(value); }
    ~semaphore() { SDL_DestroySemaphore(semaphore_); }

    bool acquireLock() { return (SDL_SemWait(semaphore_)    == 0); }
    bool tryLock()     { return (SDL_SemTryWait(semaphore_) == 0); }
	bool tryLock(unsigned ms)
	{
		// TODO: For consistency, this function should take seconds, not ms.
		return (SDL_SemWaitTimeout(semaphore_, ms) == 0);
	}
    bool releaseLock() { return (SDL_SemPost(semaphore_) == 0); }
    
    class lock
    {
    public:
        lock(semaphore& m) { semaphore_ = &m; isLocked_ = false; }
        ~lock() { if (isLocked_) release(); }
        
        bool acquire() { return (isLocked_ = semaphore_->acquireLock()); }
        bool release() { return semaphore_->releaseLock(); isLocked_ = false; }
        bool isLocked() const { return isLocked_; }
        
    protected:
        semaphore* semaphore_;
        bool isLocked_;
    };
    
    class scoped_lock : public lock
    {
    public:
        scoped_lock(semaphore& m) : lock(m) { acquire(); }
    };

private:
    SDL_sem* semaphore_;
};


} // namespace thread
} // namespace dc


#endif // _THREAD_HH_

/** vim: set ts=4 sw=4 tw=80: *************************************************/