xref: /freebsd/crypto/openssl/doc/man3/BIO_f_base64.pod (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1=pod
2
3=head1 NAME
4
5BIO_f_base64 - base64 BIO filter
6
7=head1 SYNOPSIS
8
9=for comment multiple includes
10
11 #include <openssl/bio.h>
12 #include <openssl/evp.h>
13
14 const BIO_METHOD *BIO_f_base64(void);
15
16=head1 DESCRIPTION
17
18BIO_f_base64() returns the base64 BIO method. This is a filter
19BIO that base64 encodes any data written through it and decodes
20any data read through it.
21
22Base64 BIOs do not support BIO_gets() or BIO_puts().
23
24BIO_flush() on a base64 BIO that is being written through is
25used to signal that no more data is to be encoded: this is used
26to flush the final block through the BIO.
27
28The flag BIO_FLAGS_BASE64_NO_NL can be set with BIO_set_flags()
29to encode the data all on one line or expect the data to be all
30on one line.
31
32=head1 NOTES
33
34Because of the format of base64 encoding the end of the encoded
35block cannot always be reliably determined.
36
37=head1 RETURN VALUES
38
39BIO_f_base64() returns the base64 BIO method.
40
41=head1 EXAMPLES
42
43Base64 encode the string "Hello World\n" and write the result
44to standard output:
45
46 BIO *bio, *b64;
47 char message[] = "Hello World \n";
48
49 b64 = BIO_new(BIO_f_base64());
50 bio = BIO_new_fp(stdout, BIO_NOCLOSE);
51 BIO_push(b64, bio);
52 BIO_write(b64, message, strlen(message));
53 BIO_flush(b64);
54
55 BIO_free_all(b64);
56
57Read Base64 encoded data from standard input and write the decoded
58data to standard output:
59
60 BIO *bio, *b64, *bio_out;
61 char inbuf[512];
62 int inlen;
63
64 b64 = BIO_new(BIO_f_base64());
65 bio = BIO_new_fp(stdin, BIO_NOCLOSE);
66 bio_out = BIO_new_fp(stdout, BIO_NOCLOSE);
67 BIO_push(b64, bio);
68 while ((inlen = BIO_read(b64, inbuf, 512)) > 0)
69     BIO_write(bio_out, inbuf, inlen);
70
71 BIO_flush(bio_out);
72 BIO_free_all(b64);
73
74=head1 BUGS
75
76The ambiguity of EOF in base64 encoded data can cause additional
77data following the base64 encoded block to be misinterpreted.
78
79There should be some way of specifying a test that the BIO can perform
80to reliably determine EOF (for example a MIME boundary).
81
82=head1 COPYRIGHT
83
84Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
85
86Licensed under the OpenSSL license (the "License").  You may not use
87this file except in compliance with the License.  You can obtain a copy
88in the file LICENSE in the source distribution or at
89L<https://www.openssl.org/source/license.html>.
90
91=cut
92