vmpi_distribute_work.h #1

//========= Copyright  1996-2005, Valve Corporation, All rights reserved. ============//
//
// Purpose: 
//
//=============================================================================//

#ifndef VMPI_DISTRIBUTE_WORK_H
#define VMPI_DISTRIBUTE_WORK_H
#ifdef _WIN32
#pragma once
#endif


#include "messbuf.h"
#include "utlvector.h"


class IDistributeWorkMaster
{
public:
	// Called every 200ms or so as it does the work.
	// Return true to stop distributing work.
	virtual bool Update() = 0;
};

// Before calling DistributeWork, you can set this and it'll call your Update() function.
extern IDistributeWorkMaster *g_pDistributeWorkMaster;


// You must append data to pBuf with the work unit results.
typedef void (*ProcessWorkUnitFn)( int iThread, int iWorkUnit, MessageBuffer *pBuf );

// pBuf is ready to read the results written to the buffer in ProcessWorkUnitFn.
typedef void (*ReceiveWorkUnitFn)( int iWorkUnit, MessageBuffer *pBuf, int iWorker );


// Use a CDispatchReg to register this function with whatever packet ID you give to DistributeWork.
bool DistributeWorkDispatch( MessageBuffer *pBuf, int iSource, int iPacketID );



// This is the function vrad and vvis use to divide the work units and send them out.
// It maintains a sliding window of work units so it can always keep the clients busy.
//
// The workers implement processFn to do the job work in a work unit.
// This function must send back a packet formatted with:
// cPacketID (char), cSubPacketID (char), iWorkUnit (int), (app-specific data for the results)
//
// The masters implement receiveFn to receive a work unit's results.
//
// Returns time it took to finish the work.
double DistributeWork( 
	int nWorkUnits,					// how many work units to dole out
	char cPacketID,					// This packet ID must be reserved for DistributeWork and DistributeWorkDispatch
									// must be registered with it.
	ProcessWorkUnitFn processFn,	// workers implement this to process a work unit and send results back
	ReceiveWorkUnitFn receiveFn		// the master implements this to receive a work unit
	);


// VMPI calls this before shutting down because any threads that DistributeWork has running must stop,
// otherwise it can crash if a thread tries to send data in the middle of shutting down.
void DistributeWork_Cancel();


#endif // VMPI_DISTRIBUTE_WORK_H