ROSBuzz_MISTLab/buzz_scripts/include/act/barrier.bzz

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

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


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

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

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

#
# Executes the barrier
#
function barrier_wait(threshold, transf, resumef, bc) {
  if(barrier==nil) #failsafe
    barrier_create()
  
  barrier.put(id, bc)
  barrier.get(id)
  log("--->BS: ", barrier.size(), " / ", threshold, " (", BARRIER_VSTIG, " - ", barrier.get("d"), ") t= ", timeW)
  if(barrier.size()-1 >= threshold or barrier.get("d") == 1) {
    if(barrier_allgood(barrier,bc)) {
      barrier.put("d", 1)
      timeW = 0
      BVMSTATE = transf
    } else 
      barrier.put("d", 0)
  }

  if(timeW >= BARRIER_TIMEOUT) {
    log("------> Barrier Timeout !!!!")
    barrier = nil
    timeW = 0
    BVMSTATE = resumef
  } else if(timeW % 100 == 0 and bc > 0)
    neighbors.broadcast("cmd", bc)

  timeW = timeW+1
}

# Check all members state
function barrier_allgood(barrier, bc) {
  barriergood = 1
  barrier.foreach(
    function(key, value, robot){
      #log("VS entry : ", key, " ", value, " ", robot)
      if(value != bc and key != "d"){
        barriergood = 0
      }
    }
  )
  return barriergood
}