# mystrtonum --- convert string to number

#

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

# February, 2004

# Revised June, 2014

function mystrtonum(str,        ret, n, i, k, c)

{

    if (str ~ /^0[0-7]*$/) {

        # octal

        n = length(str)

        ret = 0

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

            c = substr(str, i, 1)

            # index() returns 0 if c not in string,

            # includes c == "0"

            k = index("1234567", c)

            ret = ret * 8 + k

        }

    } else if (str ~ /^0[xX][[:xdigit:]]+$/) {

        # hexadecimal

        str = substr(str, 3)    # lop off leading 0x

        n = length(str)

        ret = 0

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

            c = substr(str, i, 1)

            c = tolower(c)

            # index() returns 0 if c not in string,

            # includes c == "0"

            k = index("123456789abcdef", c)

            ret = ret * 16 + k

        }

    } else if (str ~ \

  /^[-+]?([0-9]+([.][0-9]*([Ee][0-9]+)?)?|([.][0-9]+([Ee][-+]?[0-9]+)?))$/) {

        # decimal number, possibly floating point

        ret = str + 0

    } else

        ret = "NOT-A-NUMBER"

    return ret

}

# BEGIN {     # gawk test harness

#     a[1] = "25"

#     a[2] = ".31"

#     a[3] = "0123"

#     a[4] = "0xdeadBEEF"

#     a[5] = "123.45"

#     a[6] = "1.e3"

#     a[7] = "1.32"

#     a[8] = "1.32E2"

#

#     for (i = 1; i in a; i++)

#         print a[i], strtonum(a[i]), mystrtonum(a[i])

# }