#!/bin/ksh
################################################################################
#
# File:         date64
# Description:  Routines to handle the odd date arithmetic for the passwd(4)
#               file.
# Author:       Andrew@DeFaria.com
# Created:      Thu Oct 14 14:40:31 PDT 1999
# Language:     Korn Shell
#
# (c) Copyright 2001, Andrew@DeFaria.com, all rights reserved
#
################################################################################
# Set me to command name
me=$(basename $0)

# Set adm_base
adm_base=${adm_base:-$HOME/adm}

# Set adm_fpath
adm_fpath=${adm_fpath:-$adm_base/functions}

# Source functions
. $adm_fpath/common

# Globals
# Set up a the character map/base64 arrays for conversion
base=64
let index=00; character[$index]="."; let base64[$index]=$base*$index
let index=01; character[$index]="/"; let base64[$index]=$base*$index
let index=02; character[$index]="0"; let base64[$index]=$base*$index
let index=03; character[$index]="1"; let base64[$index]=$base*$index
let index=04; character[$index]="2"; let base64[$index]=$base*$index
let index=05; character[$index]="3"; let base64[$index]=$base*$index
let index=06; character[$index]="4"; let base64[$index]=$base*$index
let index=07; character[$index]="5"; let base64[$index]=$base*$index
let index=08; character[$index]="6"; let base64[$index]=$base*$index
let index=09; character[$index]="7"; let base64[$index]=$base*$index
let index=10; character[$index]="8"; let base64[$index]=$base*$index
let index=11; character[$index]="9"; let base64[$index]=$base*$index
let index=12; character[$index]="A"; let base64[$index]=$base*$index
let index=13; character[$index]="B"; let base64[$index]=$base*$index
let index=14; character[$index]="C"; let base64[$index]=$base*$index
let index=15; character[$index]="D"; let base64[$index]=$base*$index
let index=16; character[$index]="E"; let base64[$index]=$base*$index
let index=17; character[$index]="F"; let base64[$index]=$base*$index
let index=18; character[$index]="G"; let base64[$index]=$base*$index
let index=19; character[$index]="H"; let base64[$index]=$base*$index
let index=20; character[$index]="I"; let base64[$index]=$base*$index
let index=21; character[$index]="J"; let base64[$index]=$base*$index
let index=22; character[$index]="K"; let base64[$index]=$base*$index
let index=23; character[$index]="L"; let base64[$index]=$base*$index
let index=24; character[$index]="M"; let base64[$index]=$base*$index
let index=25; character[$index]="N"; let base64[$index]=$base*$index
let index=26; character[$index]="O"; let base64[$index]=$base*$index
let index=27; character[$index]="P"; let base64[$index]=$base*$index
let index=28; character[$index]="Q"; let base64[$index]=$base*$index
let index=29; character[$index]="R"; let base64[$index]=$base*$index
let index=30; character[$index]="S"; let base64[$index]=$base*$index
let index=31; character[$index]="T"; let base64[$index]=$base*$index
let index=32; character[$index]="U"; let base64[$index]=$base*$index
let index=33; character[$index]="V"; let base64[$index]=$base*$index
let index=34; character[$index]="W"; let base64[$index]=$base*$index
let index=35; character[$index]="X"; let base64[$index]=$base*$index
let index=36; character[$index]="Y"; let base64[$index]=$base*$index
let index=37; character[$index]="Z"; let base64[$index]=$base*$index
let index=38; character[$index]="a"; let base64[$index]=$base*$index
let index=39; character[$index]="b"; let base64[$index]=$base*$index
let index=40; character[$index]="c"; let base64[$index]=$base*$index
let index=41; character[$index]="d"; let base64[$index]=$base*$index
let index=42; character[$index]="e"; let base64[$index]=$base*$index
let index=43; character[$index]="f"; let base64[$index]=$base*$index
let index=44; character[$index]="g"; let base64[$index]=$base*$index
let index=45; character[$index]="h"; let base64[$index]=$base*$index
let index=46; character[$index]="i"; let base64[$index]=$base*$index
let index=47; character[$index]="j"; let base64[$index]=$base*$index
let index=48; character[$index]="k"; let base64[$index]=$base*$index
let index=49; character[$index]="l"; let base64[$index]=$base*$index
let index=50; character[$index]="m"; let base64[$index]=$base*$index
let index=51; character[$index]="n"; let base64[$index]=$base*$index
let index=52; character[$index]="o"; let base64[$index]=$base*$index
let index=53; character[$index]="p"; let base64[$index]=$base*$index
let index=54; character[$index]="q"; let base64[$index]=$base*$index
let index=55; character[$index]="r"; let base64[$index]=$base*$index
let index=56; character[$index]="s"; let base64[$index]=$base*$index
let index=57; character[$index]="t"; let base64[$index]=$base*$index
let index=58; character[$index]="u"; let base64[$index]=$base*$index
let index=59; character[$index]="v"; let base64[$index]=$base*$index
let index=60; character[$index]="w"; let base64[$index]=$base*$index
let index=61; character[$index]="x"; let base64[$index]=$base*$index
let index=62; character[$index]="y"; let base64[$index]=$base*$index
let index=63; character[$index]="z"; let base64[$index]=$base*$index

integer decimal_date=-1
base64_date=""

function date64_char_to_decimal {
  debug "ENTER date64_char_to_decimal"
  char="$1"
  integer i=0

  while [ $i -lt 64 ]; do
    if [ "${character[i]}" = "$char" ]; then
      break
    fi
    let i=i+1
  done

  if [ $i -eq 64 ]; then
    print -u2 "$char not found!"
    debug "RETURN -1 from date64_char_to_decimal"
    return -1
  else
    debug "RETURN $i from date64_char_to_decimal"
    return $i
  fi
} # date64_char_to_decimal

function date64_to_decimal {
  # This function accepts a 2 character "number of weeks" string as defined
in
  # passwd(4) under password aging. Specifically this string represents the
  # number of weeks since 1/1/1970 that the password was last changed. This
  # function will convert this value to a decimal number stored in the
global
  # decimal_date.
  debug "ENTER date64_to_decimal ($1)"

  # Assume failure
  decimal_date=-1

  datecode="$1"

  first_char=$(print $datecode | sed 's/.$//')
  second_char=$(print $datecode | sed 's/^.//')

  date64_char_to_decimal $first_char
  integer units_digit=$?
  if [ $units_digit -eq 255 ]; then
    error "Unable to translate the first_char \"$first_char\"" 0
    debug "RETURN -1 from date64_to_decimal - invalid units digit"
    return
  fi

  date64_char_to_decimal $second_char
  integer tens_digit=$?
  if [ $tens_digit -eq 255 ]; then
    error "Unable to translate the second_char \"$second_char\"" 0
    debug "RETURN -1 from date64_to_decimal - invalid tens digit"
    return
  fi

  let decimal_date=tens_digit*64+units_digit
  debug "RETURN $decimal_date from date64_to_decimal"
} # date64_to_decimal

function decimal_to_date64 {
  # This function will convert a decimal number representing the number of
  # weeks past 1/1/1970 and convert it to the odd base64 format described in
  # passwd(4).
  integer nbr=$1
  debug "ENTER decimal_to_date64 ($nbr)"
  i=63

  while [ $nbr -lt ${base64[i]} ]; do
    let i=i-1
  done

  let nbr=nbr-base64[i]

  tens_digit=${character[i]}
  units_digit=${character[nbr]}
  base64_date="$units_digit$tens_digit"
  debug "RETURN $base64_date from decimal_to_date64 ($nbr)"
} # decimal_to_date64