NAME

       BIO_f_readbuffer - read only buffering BIO that supports BIO_tell() and BIO_seek()

SYNOPSIS

        #include <openssl/bio.h>

        const BIO_METHOD *BIO_f_readbuffer(void);

DESCRIPTION

       BIO_f_readbuffer() returns the read buffering BIO method.

       This BIO filter can be inserted on top of BIO's that do not support BIO_tell() or
       BIO_seek() (e.g. A file BIO that uses stdin).

       Data read from a read buffering BIO comes from an internal buffer which is filled from the
       next BIO in the chain.

       BIO_gets() is supported for read buffering BIOs.  Writing data to a read buffering BIO is
       not supported.

       Calling BIO_reset() on a read buffering BIO does not clear any buffered data.

NOTES

       Read buffering BIOs implement BIO_read_ex() by using BIO_read_ex() operations on the next
       BIO (e.g. a file BIO) in the chain and storing the result in an internal buffer, from
       which bytes are given back to the caller as appropriate for the call. BIO_read_ex() is
       guaranteed to give the caller the number of bytes it asks for, unless there's an error or
       end of communication is reached in the next BIO. The internal buffer can grow to cache the
       entire contents of the next BIO in the chain. BIO_seek() uses the internal buffer, so that
       it can only seek into data that is already read.

RETURN VALUES

       BIO_f_readbuffer() returns the read buffering BIO method.

SEE ALSO

       bio(7), BIO_read(3), BIO_gets(3), BIO_reset(3), BIO_ctrl(3).

COPYRIGHT

       Copyright 2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (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 <https://www.openssl.org/source/license.html>.