#!/usr/bin/perl

use warnings;
use strict;

use IPC::SysV qw(IPC_CREAT ftok SEM_UNDO);
use IPC::Semaphore;

my $semtok = ftok($0,1);
my $shmtok = ftok($0,2);

my $sem = IPC::Semaphore->new($semtok, 1, 0700 | IPC_CREAT)
  or die "Couldn't create semaphore: $!\n";
my $shmid = shmget($shmtok,4,0700 | IPC_CREAT)
  or die "Couldn't create shm: $!\n";

if ($ENV{RESET})
{
  $sem->setval(0,0);
  my $buf = pack("L",0);

  shmwrite($shmid, $buf, 0, 4)
    or die "shmwrite failed: $!\n";
  if (!$ARGV[0])
  {
    exit(0);
  }
}


foreach my $i(1..$ARGV[0]||100)
{
  my $r = add(1);
  if ($ENV{VERBOSE})
  {
    print $r,"\n";
  }
}

sub add
{
  my($add) = @_;
  # Lock: wait for 0, then semaphore up
  $sem->op(0, 0, 0,
           0, 1, 0)
    or die "semaphore lock failed: $!\n";

  # Read counter
  my $buf;
  shmread($shmid, $buf, 0, 4)
    or die "shmread failed: $!\n";
  my $val = unpack("L",$buf);
  # Increment
  $val += $add;
  # Write it back
  $buf = pack("L",$val);
  shmwrite($shmid, $buf, 0, 4)
    or die "shmwrite failed: $!\n";

  # Now unlock; semaphore down
  $sem->op(0, -1, 0)
    or die "semaphore unlock failed: $!\n";

  return $val;
}

##</code><code>##

#!/usr/bin/perl

use warnings;
use strict;

use DBI;
our $dbh = DBI->connect('DBI:mysql:database=test','db_user','db_pass')
    or die "Couldn't connect to db\n";
our $sth = $dbh->prepare("UPDATE counter SET count = count + ?")
    or die "Couldn't prepare statement\n";

foreach my $i(1..$ARGV[0]||100)
{
  my $r = add(1);
}

sub add
{
    $sth->execute($_[0])
        or die "Couldn't to SQL: $!\n";
}


##</code><code>##

#include <sys/mman.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <iostream>

#include <bits/atomicity.h>
using __gnu_cxx::__atomic_add;
using __gnu_cxx::__exchange_and_add;
using namespace std;

void die(char *msg) {
  perror(msg);
  exit(0);
}

void add(volatile _Atomic_word *to, int amt) {
  __atomic_add(to, amt);
}

int main(int argc, char *argv[]) {
  if (argc < 2) {
    die("bad usage");
  }
  int mmap_fd = open(argv[1], O_RDWR);
  if (mmap_fd < 0)
    die("couldn't open mmap");
  void *mem = mmap(NULL, sizeof(_Atomic_word), PROT_WRITE, MAP_SHARED, mmap_fd, 0);
  if (mem == NULL)
    die("couldn't mmap file");
  volatile _Atomic_word *counter = (volatile _Atomic_word *)mem;

  int count = atoi(argv[2]);
  for(int i=0;i<count;i++) {
    add(counter, 1);
  }
  cout << "counter is now " << *counter << endl;
}