1.\"	$OpenBSD: BIO_f_base64.3,v 1.11 2019/06/06 01:06:58 schwarze Exp $
2.\"	OpenSSL fc1d88f0 Wed Jul 2 22:42:40 2014 -0400
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52.Dd $Mdocdate: June 6 2019 $
53.Dt BIO_F_BASE64 3
54.Os
55.Sh NAME
56.Nm BIO_f_base64
57.Nd base64 BIO filter
58.Sh SYNOPSIS
59.In openssl/bio.h
60.In openssl/evp.h
61.Ft const BIO_METHOD *
62.Fo BIO_f_base64
63.Fa void
64.Fc
65.Sh DESCRIPTION
66.Fn BIO_f_base64
67returns the base64 BIO method.
68This is a filter BIO that base64 encodes any data written through it
69and decodes any data read through it.
70.Pp
71Base64 BIOs do not support
72.Xr BIO_gets 3
73or
74.Xr BIO_puts 3 .
75.Pp
76.Xr BIO_flush 3
77on a base64 BIO that is being written through
78is used to signal that no more data is to be encoded:
79this is used to flush the final block through the BIO.
80.Pp
81To encode the data all on one line and to expect the data to be all
82on one line, initialize the base64 BIO as follows:
83.Bd -literal -offset indent
84BIO *b64 = BIO_new(BIO_f_base64());
85BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
86.Ed
87.Sh RETURN VALUES
88.Fn BIO_f_base64
89returns the base64 BIO method.
90.Sh EXAMPLES
91Base64 encode the string "Hello World\en"
92and write the result to standard output:
93.Bd -literal -offset indent
94BIO *bio, *b64;
95char message[] = "Hello World \en";
96
97b64 = BIO_new(BIO_f_base64());
98bio = BIO_new_fp(stdout, BIO_NOCLOSE);
99BIO_push(b64, bio);
100BIO_write(b64, message, strlen(message));
101BIO_flush(b64);
102
103BIO_free_all(b64);
104.Ed
105.Pp
106Read Base64-encoded data from standard input
107and write the decoded data to standard output:
108.Bd -literal -offset indent
109BIO *bio, *b64, *bio_out;
110char inbuf[512];
111int inlen;
112
113b64 = BIO_new(BIO_f_base64());
114bio = BIO_new_fp(stdin, BIO_NOCLOSE);
115bio_out = BIO_new_fp(stdout, BIO_NOCLOSE);
116BIO_push(b64, bio);
117while((inlen = BIO_read(b64, inbuf, 512)) > 0)
118	BIO_write(bio_out, inbuf, inlen);
119
120BIO_flush(bio_out);
121BIO_free_all(b64);
122.Ed
123.Sh SEE ALSO
124.Xr BIO_new 3 ,
125.Xr EVP_EncodeInit 3
126.Sh HISTORY
127.Fn BIO_f_base64
128first appeared in SSLeay 0.6.5 and has been available since
129.Ox 2.4 .
130.Sh BUGS
131The ambiguity of EOF in base64-encoded data can cause additional
132data following the base64-encoded block to be misinterpreted.
133.Pp
134There should be some way of specifying a test that the BIO can perform
135to reliably determine EOF (for example a MIME boundary).
136