/* -*- 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 */
