ROSBuzz_MISTLab/buzz_scripts/include/barrier.bzz

########################################
#
# BARRIER-RELATED FUNCTIONS
#
########################################

#
# Constants
#
BARRIER_TIMEOUT = 200 # in steps
BARRIER_VSTIG = 80
timeW = 0
barrier = nil

#
# Sets a barrier
#
function barrier_create() {
  # reset
  timeW = 0
  # create barrier vstig
  #log("---> Prev. br. ", barrier, " ", BARRIER_VSTIG)
  if(barrier!=nil) {
    barrier=nil
    BARRIER_VSTIG = BARRIER_VSTIG +1
  }
  #log("---> New. br. ", barrier, " ", BARRIER_VSTIG)
  barrier = stigmergy.create(BARRIER_VSTIG)
}

function barrier_set(threshold, transf, resumef, bdt) {
  statef = function() {
    barrier_wait(threshold, transf, resumef, bdt);
  }
  UAVSTATE = "BARRIERWAIT"
  barrier_create()
}

#
# Make yourself ready
#
function barrier_ready() {
  log("BARRIER READY -------")
  barrier.put(id, 1)
  barrier.put("d", 0)
}

#
# Executes the barrier
#
function barrier_wait(threshold, transf, resumef, bdt) {
  barrier.put(id, 1)

  barrier.get(id)
  #log("----->BS: ", barrier.size())
  if(barrier.size() - 1 >= threshold or barrier.get("d") == 1) {
    barrier.put("d", 1)
    timeW = 0
    transf()
  } else if(timeW >= BARRIER_TIMEOUT) {
    log("------> Barrier Timeout !!!!")
    timeW = 0
    resumef()
  }

  if(bdt!=-1)
    neighbors.broadcast("cmd", bdt)

  timeW = timeW+1
}

# get the lowest id of the fleet, but requires too much bandwidth...
function getlowest(){
  Lid = 15;
  u=15
  while(u>=0){
				tab = barrier.get(u)
				if(tab!=nil){
          if(tab<Lid)
            Lid=tab
        }
        u=u-1
  }
  log("--> LOWEST ID:",Lid)
}