SquirrelJME/SquirrelJME

#!/bin/sh
# ---------------------------------------------------------------------------
# Multi-Phasic Applications: SquirrelJME
#     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
#     Copyright (C) Multi-Phasic Applications <multiphasicapps.net>
# ---------------------------------------------------------------------------
# SquirrelJME is under the GNU General Public License v3, or later.
# See license.mkd for licensing and copyright information.
# ---------------------------------------------------------------------------
# DESCRIPTION: Outputs some random bytes as hexadecimal

# Force C locale
export LC_ALL=C

# Directory of this script
__exedir="$(dirname -- "$0")"

# Need count?
if [ "$#" -le "0" ]
then
    echo "Usage: $0 (count)"
    exit 1
fi

# If outputting no bytes, ignore
__count="$1"
if [ "$__count" -le "0" ]
then
    exit 0
fi

# Real random source, if it exists
if [ -c /dev/urandom ] || [ -c /dev/random ]
then
    # Unblocked
    (if [ -c /dev/urandom ]
    then
        dd if=/dev/urandom "bs=$__count" count=1
        
    # Normal
    else
        dd if=/dev/random "bs=$__count" count=1
    fi) 2> /dev/null | hexdump -x |
        sed 's/^[0-9a-fA-F]\{1,\}//g' | tr -d ' ' | tr -d '\n' | tr -d '\t'
    
    # End with newline
    echo ""

# Not really random, but something
else
    # Seed the random number generator and get a value
    __seed="$( (echo -n $$ & echo -n $!; date +%s & echo -n $!) |
        tr -d ' ' | tr -d '\n' | sed 's/[^0-9]*//g' | cut -c 1-8)"
    
    # Loop
    __i=0
    while [ "$__i" -lt "$__count" ]
    do
        # Calculate a value
        __a="$(expr $__seed '*' 1337 | cut -c 1-8)"
        
        # Set new seed
        echo -n "" &
        __pid="$!"
        __seed="$__a$__pid"
        
        # Add all of the seed values together
        __rest="$__seed"
        __xa="0"
        __xb="1"
        __j="0"
        while [ -n "$__rest" ]
        do
            __char="$(echo "$__rest" | cut -c 1)"
            
            # Add to A or B?
            if [ "$__j" -eq "0" ]
            then
                __xa="$(expr "$__xa" + "$__char")"
                __j="1"
            else
                __xb="$(expr "$__xb" + "$__char")"
                __j="0"
            fi
            
            # Cut character
            __rest="$(echo "$__rest" | cut -c 2-)"
        done
        
        # Modulo 16 for hex
        __ya="$(expr $__xa % 16)"
        __yb="$(expr $__xb % 16)"
        
        # Echo individual hex characters
        for __q in $__ya $__yb
        do
            case $__q in
                10) printf '%s' "a";;
                11) printf '%s' "b";;
                12) printf '%s' "c";;
                13) printf '%s' "d";;
                14) printf '%s' "e";;
                15) printf '%s' "f";;
                *) printf '%s' "$__q";;
            esac
        done
        
        # Increment
        __i="$(expr $__i + 1)"
    done
    
    # End with newline
    echo ""
fi