## SYNOPSIS

use Business::BR::CPF;

print "ok " if test_cpf('390.533.447-05'); # prints 'ok '

print "bad " unless test_cpf('231.002.999-00'); # prints 'bad '

## DESCRIPTION

The CPF number is an identification number of Brazilian citizens emitted by the Brazilian Ministry of Revenue, which is called ``Ministerio da Fazenda''.CPF stands for ``Cadastro de Pessoa Fisica'' (literally, physical person registration) as opposed to the CNPJ number for companies.

The CPF is comprised of a base of 9 digits and 2 check digits. It is usually written like '231.002.999-00' so as to be more human-readable.

This module provides `"test_cpf"` for checking that a CPF number
is *correct*. Here a *correct **CPF** number* means

- it is 11 digits long
- it satisfies the two check equations mentioned below

Before checking, any non-digit letter is stripped, making it easy to test formatted entries like '231.002.999-00' and entries with extra blanks like ' 999.221.222-00 '.

**test_cpf**-
test_cpf('999.444.333-55') # incorrect CPF, returns 0 test_cpf(' 263.946.533-30 ') # is ok, returns 1 test_cpf('888') # nope, returns undef

Tests whether a CPF number is correct. Before testing, any non-digit character is stripped. Then it is expected to be 11 digits long and to satisfy two check equations which validate the last two check digits. See ``THE CHECK EQUATIONS''.

The policy to get rid of '.' and '-' is very liberal. It indeeds discards anything that is not a digit (0, 1, ..., 9) or letter. That is handy for discarding spaces as well

test_cpf(' 263.946.533-30 ') # is ok, returns 1

But extraneous inputs like '#333%444*2.3+2-00' are also accepted. If you are worried about this kind of input, just check against a regex:

warn "bad CPF: only digits (11) expected" unless ($cpf =~ /^\d{11}$/); warn "bad CPF: does not match mask '___.___.___-__'" unless ($cpf =~ /^\d{3}\.\d{3}\.\d{3}-\d{2}$/);

NOTE. Integer numbers like 9999811299 (or 99_998_112_99) with fewer than 11 digits will be normalized (eg. to ``09999811299'') before testing.

**canon_cpf**-
canon_cpf(99); # returns '00000000099' canon_cpf('999.999.999-99'); # returns '99999999999'

Brings a candidate for a CPF number to a canonical form. In case, the argument is an integer, it is formatted to at least eleven digits. Otherwise, it is stripped of any non-alphanumeric characters and returned as it is.

**format_cpf**-
format_cpf('00000000000'); # returns '000.000.000-00'

Formats its input into '000.000.000-00' mask. First, the argument is canon'ed and then dots and hyphen are added to the first 11 digits of the result.

**parse_cpf**-
($base, $dv) = parse_cpf($cpf); $hashref = parse_cpf('999.222.111-00'); # { base => '999222111', dv => '00' }

Splits a candidate for CPF number into base and check digits (dv - digitos de verificaca~o). It canon's the argument before splitting it into 9- and 2-digits parts. In a list context, returns a two-element list with the base and the check digits. In a scalar context, returns a hash ref with keys 'base' and 'dv' and associated values.

**random_cpf**-
$rand_cpf = random_cpf($valid); $correct_cpf = random_cpf(); $cpf = random_cpf(1); # also a correct CPF $bad_cpf = random_cpf(0); # an incorrect CPF

Generates a random CPF. If

`$valid`is omitted or 1, it is guaranteed to be*correct*. If`$valid`is 0, it is guaranteed to be*incorrect*. This function is intented for mass test. (Use it wisely.)The implementation is simple: just generate a 9-digits random number, hopefully with a uniform distribution and then compute the check digits. If

`$valid`==0, the check digits are computed**not to**satisfy the check equations.

## EXPORT

`"test_cpf"`is exported by default.

`"canon_cpf"`,

`"format_cpf"`,

`"parse_cpf"`and

`"random_cpf"`can be exported on demand.

## THE CHECK EQUATIONS

A correct CPF number has two check digits which are computed from the base 9 first digits. Consider the CPF number written as 11 digits

c[1] c[2] c[3] c[4] c[5] c[6] c[7] c[8] c[9] dv[1] dv[2]

To check whether a CPF is correct or not, it has to satisfy the check equations:

c[1]*10+c[2]*9+c[3]*8+c[4]*7+c[5]*6+ c[6]*5+c[7]*4+c[8]*3+c[9]*2+dv[1] = 0 (mod 11) or = 1 (mod 11) (if dv[1]=0)

and

c[2]*10+c[3]*9+c[4]*8+c[5]*7+c[6]*6+ c[7]*5+c[8]*4+c[9]*3+dv[1]*2+dv[2] = 0 (mod 11) or = 1 (mod 11) (if dv[2]=0)

## BUGS

I heard that there are exceptions of CPF numbers which don't obey the check equations and are still authentic. I have never found one of them.## AUTHOR

A. R. Ferreira, <[email protected]>## COPYRIGHT AND LICENSE

Copyright (C) 2005 by A. R. FerreiraThis library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.6 or, at your option, any later version of Perl 5 you may have available.