# translate.awk --- do tr-like stuff

#

# Arnold Robbins, arnold@skeeve.com, Public Domain

# August 1989

# February 2009 - bug fix

# Bugs: does not handle things like tr A-Z a-z; it has

# to be spelled out. However, if `to' is shorter than `from',

# the last character in `to' is used for the rest of `from'.

function stranslate(from, to, target,     lf, lt, ltarget, t_ar, i, c,

                                                               result)

{

    lf = length(from)

    lt = length(to)

    ltarget = length(target)

    for (i = 1; i <= lt; i++)

        t_ar[substr(from, i, 1)] = substr(to, i, 1)

    if (lt < lf)

        for (; i <= lf; i++)

            t_ar[substr(from, i, 1)] = substr(to, lt, 1)

    for (i = 1; i <= ltarget; i++) {

        c = substr(target, i, 1)

        if (c in t_ar)

            c = t_ar[c]

        result = result c

    }

    return result

}

function translate(from, to)

{

    return $0 = stranslate(from, to, $0)

}

# main program

BEGIN {

    if (ARGC < 3) {

        print "usage: translate from to" > "/dev/stderr"

        exit

    }

    FROM = ARGV[1]

    TO = ARGV[2]

    ARGC = 2

    ARGV[1] = "-"

}

{

    translate(FROM, TO)

    print

}