=pod

=head1 NAME

BIO_f_base64 - base64 BIO filter

=head1 SYNOPSIS

 #include <openssl/bio.h>
 #include <openssl/evp.h>

 const BIO_METHOD *     BIO_f_base64(void);

=head1 DESCRIPTION

BIO_f_base64() returns the base64 BIO method. This is a filter
BIO that base64 encodes any data written through it and decodes
any data read through it.

Base64 BIOs do not support BIO_gets() or BIO_puts().

BIO_flush() on a base64 BIO that is being written through is
used to signal that no more data is to be encoded: this is used
to flush the final block through the BIO.

The flag BIO_FLAGS_BASE64_NO_NL can be set with BIO_set_flags()
to encode the data all on one line or expect the data to be all
on one line.

=head1 NOTES

Because of the format of base64 encoding the end of the encoded
block cannot always be reliably determined.

=head1 RETURN VALUES

BIO_f_base64() returns the base64 BIO method.

=head1 EXAMPLES

Base64 encode the string "Hello World\n" and write the result
to standard output:

 BIO *bio, *b64;
 char message[] = "Hello World \n";

 b64 = BIO_new(BIO_f_base64());
 bio = BIO_new_fp(stdout, BIO_NOCLOSE);
 BIO_push(b64, bio);
 BIO_write(b64, message, strlen(message));
 BIO_flush(b64);

 BIO_free_all(b64);

Read Base64 encoded data from standard input and write the decoded
data to standard output:

 BIO *bio, *b64, *bio_out;
 char inbuf[512];
 int inlen;

 b64 = BIO_new(BIO_f_base64());
 bio = BIO_new_fp(stdin, BIO_NOCLOSE);
 bio_out = BIO_new_fp(stdout, BIO_NOCLOSE);
 BIO_push(b64, bio);
 while((inlen = BIO_read(b64, inbuf, 512)) > 0)
        BIO_write(bio_out, inbuf, inlen);

 BIO_flush(bio_out);
 BIO_free_all(b64);

=head1 BUGS

The ambiguity of EOF in base64 encoded data can cause additional
data following the base64 encoded block to be misinterpreted.

There should be some way of specifying a test that the BIO can perform
to reliably determine EOF (for example a MIME boundary).

=head1 COPYRIGHT

Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

=cut
