ran

#!/bin/sh
mseed() {
  [ -c /dev/urandom -a ! "$PID" ] && {
    read -r seed < /dev/urandom # read a single line of urandom
    seed=${#seed}
  } || { # otherwise generate a seed using pids
  # $PID may be set to force usage of pids
    echo '!!USING PIDS!!' >&2
    : & wait; o="$!"; for i in 1 2 3 4 5; do
      : & wait # generate new $!
      o=$((o%o+$!*o))
    done
    for i in 1 2 3; do
      : & wait
    done
    seed="$((o%o+$!*${#o}))" # greatly shorten seed
    # large seeds produce large numbers = more randomness
  }
  # L105
  [ -c /dev/urandom ] && {
    read -r o < /dev/urandom
    o="${#o}"
  } || {
    # warn about lack of hardware randomness
    : & wait
    o="$!" # pid is "RANDOM"
    for i in 1 2 3; do
      : & wait
    done # 3 pid calls
    o="$((o%o*o+$!))" # this allows the last digit to actually be random
  } 
  : $((seed+=o))
  # use $o to add possibility of odd number
  printf '%s\n' "$seed"
}
# make seed ^
sadd() {
  str="$1"
  while [ "$str" ]; do
    next="${str#?}"; current="${str%$next}"
    out=$(($(printf "%d" "\"$current")+${out:-0}))
    str="$next"
  done
  printf '%s\n' "$out"
  unset out str next
}
unset s0 s1 seed


[ "$1" ] || set -- "$(mseed)" "$(mseed)" "uran"
[ "$1" -a ! "$2" ] && set -- $1 0
# first check if $2 is unset
## if $2 is unset, $3 will also be unset
if [ ! "$PID" ] && [ "$3" != "uran" ]; then
  PID="$3"
fi
# PID vs uran actually has no effect if a seed is given
[ "$1" = "-" -a "$2" = "-" -a "$3" ] && {
  [ "$3" != "uran" ] && PID="$3"
  set -- "$(mseed)" "$(mseed)" "$3"
}

[ "$1" -eq "$1" ] 2>/dev/null || {
  set -- $(sadd "$1") "$2" "$3"
}
[ "$2" -eq "$2" ] 2>/dev/null || {
  set -- "$1" "$(sadd $2)" "$3"
}
# sadd should add together all the ascii values of $1

set -- ${1:-$(mseed)} ${2:-$(mseed)}
# then mseed takes over

s0="$1"; s1="$2"

# if no second seed is given, default to 0
# otherwise the output will differ for each seed
##
# the better idea is to take $1 and split it
# however this requires the $1 be at least 2char in size


# an attempt at xoroshiro64** follows
# this is based off the reference code @ https://prng.di.unimi.it/xoroshiro64starstar.c
# keep in mind I have no idea how most of this works
rotl() {
  echo $(( ($1 << $2) | ( $1 >> (32 - $2) ) ))
} # return (x << k) | (x >> (32 - k))
next() {
  # s0/s1 are generated above @ L42-49
  : $((s1 ^= s0))
  s0=$(($(rotl s0 26) ^ s1 ^ (s1 << 9)))
  s1=$(rotl $s1 13)
  echo $(($(rotl $((s0*0x9E3779BB)) 5)*5)) # result
}
o=$(next); echo 0.${o#-}