#!/bin/sh

fname=$(basename $0)

usage () {
  echo "$fname [options]"
  echo 'Display the most memory intensive processes
memory pid process

  Options:
    -h        Display help
    -n <int>  Top n processes. Default 10
    -p <pid>  Operate on given process id
    -m        Full memory map of processes, sorted by usage'
}

nmax=10
unset process map

while getopts ":hn:p:m" opt;
do
  case $opt in
    h)
      usage
      exit 0
      ;;
    n)
      if ! echo $OPTARG | grep -Eq '^[0-9]+$'
      then
        error "n argument has to be an integer"
        exit 2
      fi
      if [ -z "$OPTARG" ]
      then
        error "n needs an argument"
        exit 2
      fi
      if [ "$OPTARG" -lt 1 ]
      then
        error "n argument has to be greater than 0"
        exit 2
      fi
      nmax=$OPTARG
      ;;
    p)
      process=$OPTARG
      ;;
    m)
      map=y
      ;;
    \?)
    	echo "Uknown option: $OPTARG"
      usage
      exit 1
    	;;
  esac
done

shift $((OPTIND-1))


if [ -n "$process" ] ; then
  LIST=$(ps -q $process -eo "rss,pid,comm" | tail -n1)
else
  LIST=$(ps -eo "rss,pid,comm" | tail -n+2 | sort -g | tail -n$nmax | tac)
fi

if [ -n "$map" ]
then

  plist=$(echo "$LIST" | awk '{print $2}')

  flist=""

  for i in $plist
  do
    if [ -z "$flist" ]
    then
      flist=$(pmap -x $i | tail -n+3 | head -n-2)
    else
      flist=$(printf "%s\n%s" "$flist" "$(pmap -x $i | tail -n+3 | head -n-2)")
    fi
  done

  echo "$flist" | sort -nk3

else

  echo "$LIST" | awk '{
  if(int($1/1048576)>0) {
    p=int($1/1048576)"G"
  }
  else if(int($1/1024)>0) {
    p=int($1/1024)"M"
  }
  else {
    p=$1"K"
  }
  printf "%5s %5s %s\n", p, $2, $3
  }'

fi