2015/advent7.sh

   1 unset wires cache
   2 declare -A wires cache
   3 shopt -s extglob
   4 count=0
   5 while IFS=, read op wire; do
   6     wires[$wire]="$op"
   7     count=$((count+1))
   8 done < <(sed 's/ -> /,/')
   9 echo "found $count wires"
  10 # Find wire $1, store its value in $val. Recursive.
  11 indent=
  12 call=0
  13 get() {
  14     call=$((call+1))
  15     if [[ call -gt $((count**2)) ]]; then
  16         echo "recursing too deep!"; exit 1
  17     fi
  18     local a b vala valb mycall
  19     mycall=$call
  20     echo "$indent$mycall: looking up wire/value $1 (${wires[$1]})"
  21     indent+=" "
  22     if [[ ${cache[$1]+set} ]]; then
  23         indent=${indent#?}
  24         echo "${indent}cached: ${cache[$1]}"
  25         val=${cache[$1]}
  26         return;
  27     fi
  28     case $1_${wires[$1]} in
  29         *[0-9]_*) val=$1 ;;
  30         *AND*) read a ignore b <<< "${wires[$1]}"
  31                get $a
  32                vala=$val
  33                get $b
  34                valb=$val
  35                val=$((vala & valb));;
  36         *OR*) read a ignore b <<< "${wires[$1]}"
  37               get $a
  38               vala=$val
  39               get $b
  40               valb=$val
  41               val=$((vala | valb));;
  42         *NOT*) read ignore a <<< "${wires[$1]}"
  43               get $a
  44               vala=$val
  45               val=$((~vala & 0xffff));;
  46         *LSHIFT*) read a ignore b <<< "${wires[$1]}"
  47                   get $a
  48                   vala=$val
  49                   val=$(((vala << b) & 0xffff));;
  50         *RSHIFT*) read a ignore b <<< "${wires[$1]}"
  51                   get $a
  52                   vala=$val
  53                   val=$((vala >> b));;
  54         *) get ${wires[$1]} ;;
  55     esac
  56     indent=${indent#?}
  57     printf "$indent$mycall: wire $1 contains 0x%x (%d)\n" "$val" "$val"
  58     cache[$1]=$val
  59 }
  60 get ${1:-a}
  61 if [[ ${1:-a} == a ]]; then
  62     echo "rewriting wire b"
  63     unset cache
  64     declare -A cache
  65     wires[b]=$val
  66     get a
  67 fi