/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/***********************************************************************
**  1996 - Netscape Communications Corporation
**
** Name: cvar.c
**
** Description: Tests Condition Variable Operations 
**
** Modification History:
** 13-May-97 AGarcia- Converted the test to accomodate the debug_mode flag.
**	         The debug mode will print all of the printfs associated with this test.
**			 The regress mode will be the default mode. Since the regress tool limits
**           the output to a one line status:PASS or FAIL,all of the printf statements
**			 have been handled with an if (debug_mode) statement.
** 04-June-97 AGarcia removed the Test_Result function. Regress tool has been updated to
**			recognize the return code from tha main program.
** 12-June-97 Revert to return code 0 and 1.
***********************************************************************/

/***********************************************************************
** Includes
***********************************************************************/

#include "nspr.h"

/* Used to get the command line option */
#include "plgetopt.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

PRMonitor *mon;
#define DEFAULT_COUNT   1000
PRInt32 count = 0;
PRIntn debug_mode;

#define kQSIZE	1

typedef struct {
	PRLock		*bufLock;
	int			startIdx;
	int			numFull;
	PRCondVar	*notFull;
	PRCondVar	*notEmpty;
	void		*data[kQSIZE];
} CircBuf;

static PRBool failed = PR_FALSE;

/*
** NewCB creates and initializes a new circular buffer.
*/
static CircBuf* NewCB(void)
{
	CircBuf		*cbp;
	
	cbp = PR_NEW(CircBuf);
	if (cbp == NULL)
		return (NULL);
		
	cbp->bufLock 	= PR_NewLock();
	cbp->startIdx 	= 0;
	cbp->numFull 	= 0;
	cbp->notFull	= PR_NewCondVar(cbp->bufLock);
	cbp->notEmpty	= PR_NewCondVar(cbp->bufLock);
	
	return (cbp);
}

/*
** DeleteCB frees a circular buffer.
*/
static void DeleteCB(CircBuf *cbp)
{
	PR_DestroyLock(cbp->bufLock);
	PR_DestroyCondVar(cbp->notFull);
	PR_DestroyCondVar(cbp->notEmpty);
	PR_DELETE(cbp);
}


/*
** PutCBData puts new data on the queue.  If the queue is full, it waits 
** until there is room.
*/
static void PutCBData(CircBuf *cbp, void *data)
{
	PR_Lock(cbp->bufLock);
	/* wait while the buffer is full */
	while (cbp->numFull == kQSIZE)
		PR_WaitCondVar(cbp->notFull,PR_INTERVAL_NO_TIMEOUT);
	cbp->data[(cbp->startIdx + cbp->numFull) % kQSIZE] = data;
	cbp->numFull += 1;
	
	/* let a waiting reader know that there is data */
	PR_NotifyCondVar(cbp->notEmpty);
	PR_Unlock(cbp->bufLock);

}


/*
** GetCBData gets the oldest data on the queue.  If the queue is empty, it waits 
** until new data appears.
*/
static void* GetCBData(CircBuf *cbp)
{
	void *data;
	
	PR_Lock(cbp->bufLock);
	/* wait while the buffer is empty */
	while (cbp->numFull == 0)
		PR_WaitCondVar(cbp->notEmpty,PR_INTERVAL_NO_TIMEOUT);
	data = cbp->data[cbp->startIdx];
	cbp->startIdx =(cbp->startIdx + 1) % kQSIZE;
	cbp->numFull -= 1;
	
	/* let a waiting writer know that there is room */
	PR_NotifyCondVar(cbp->notFull);
	PR_Unlock(cbp->bufLock);
	
	return (data);
}


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

static int alive;

static void PR_CALLBACK CXReader(void *arg)
{
	CircBuf *cbp = (CircBuf *)arg;
    PRInt32 i, n;
    void *data;

    n = count / 2;
    for (i = 0; i < n; i++) {
		data = GetCBData(cbp);
		if ((int)data != i)
    		if (debug_mode) printf("data mismatch at for i = %d usec\n", i);
    }
 
    PR_EnterMonitor(mon);
    --alive;
    PR_Notify(mon);
    PR_ExitMonitor(mon);
}

static void PR_CALLBACK CXWriter(void *arg)
{
	CircBuf *cbp = (CircBuf *)arg;
    PRInt32 i, n;

    n = count / 2;
    for (i = 0; i < n; i++)
		PutCBData(cbp, (void *)i);

    PR_EnterMonitor(mon);
    --alive;
    PR_Notify(mon);
    PR_ExitMonitor(mon);
}

static void CondWaitContextSwitch(PRThreadScope scope1, PRThreadScope scope2)
{
    PRThread *t1, *t2;
	CircBuf *cbp;

    PR_EnterMonitor(mon);

    alive = 2;

	cbp =  NewCB();

	t1 = PR_CreateThread(PR_USER_THREAD,
				      CXReader, cbp, 
				      PR_PRIORITY_NORMAL,
				      scope1,
    				  PR_UNJOINABLE_THREAD,
				      0);
	PR_ASSERT(t1);
	t2 = PR_CreateThread(PR_USER_THREAD,
				      CXWriter, cbp, 
				      PR_PRIORITY_NORMAL,
				      scope2,
    				  PR_UNJOINABLE_THREAD,
				      0);
	PR_ASSERT(t2);

    /* Wait for both of the threads to exit */
    while (alive) {
	PR_Wait(mon, PR_INTERVAL_NO_TIMEOUT);
    }

	DeleteCB(cbp);

    PR_ExitMonitor(mon);
}

static void CondWaitContextSwitchUU(void)
{
    CondWaitContextSwitch(PR_LOCAL_THREAD, PR_LOCAL_THREAD);
}

static void CondWaitContextSwitchUK(void)
{
    CondWaitContextSwitch(PR_LOCAL_THREAD, PR_GLOBAL_THREAD);
}

static void CondWaitContextSwitchKK(void)
{
    CondWaitContextSwitch(PR_GLOBAL_THREAD, PR_GLOBAL_THREAD);
}

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

static void Measure(void (*func)(void), const char *msg)
{
    PRIntervalTime start, stop;
    double d;

    start = PR_IntervalNow();
    (*func)();
    stop = PR_IntervalNow();

    d = (double)PR_IntervalToMicroseconds(stop - start);

    if (debug_mode) printf("%40s: %6.2f usec\n", msg, d / count);

    if (0 ==  d) failed = PR_TRUE;
}

static PRIntn PR_CALLBACK RealMain(int argc, char **argv)
{
	/* The command line argument: -d is used to determine if the test is being run
	in debug mode. The regress tool requires only one line output:PASS or FAIL.
	All of the printfs associated with this test has been handled with a if (debug_mode)
	test.
	Usage: test_name [-d] [-c n]
	*/
	PLOptStatus os;
	PLOptState *opt = PL_CreateOptState(argc, argv, "dc:");
	while (PL_OPT_EOL != (os = PL_GetNextOpt(opt)))
    {
		if (PL_OPT_BAD == os) continue;
        switch (opt->option)
        {
        case 'd':  /* debug mode */
			debug_mode = 1;
            break;
        case 'c':  /* loop count */
            count = atoi(opt->value);
            break;
         default:
            break;
        }
    }
	PL_DestroyOptState(opt);

    if (0 == count) count = DEFAULT_COUNT;

    mon = PR_NewMonitor();

    Measure(CondWaitContextSwitchUU, "cond var wait context switch- user/user");
    Measure(CondWaitContextSwitchUK, "cond var wait context switch- user/kernel");
    Measure(CondWaitContextSwitchKK, "cond var wait context switch- kernel/kernel");

	PR_DestroyMonitor(mon);

	if (debug_mode) printf("%s\n", (failed) ? "FAILED" : "PASSED");

	if(failed)
		return 1;
	else
		return 0;
}


int main(int argc, char *argv[])
{
    PRIntn rv;
    
    PR_STDIO_INIT();
    rv = PR_Initialize(RealMain, argc, argv, 0);
    return rv;
}  /* main */