openssl1.0/doc/crypto/BIO_f_base64.pod

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2019-08-09 10:00:55 +02:00
=pod
=head1 NAME
BIO_f_base64 - base64 BIO filter
=head1 SYNOPSIS
#include <openssl/bio.h>
#include <openssl/evp.h>
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 SEE ALSO
TBA