Add docs for CMS_final() and BIO_new_CMS().

=pod

=head1 NAME

BIO_new_CMS - CMS streaming filter BIO

=head1 SYNOPSIS

 #include <openssl/cms.h>

 BIO *BIO_new_CMS(BIO *out, CMS_ContentInfo *cms);

=head1 DESCRIPTION

BIO_new_CMS() returns a streaming filter BIO chain based on B<cms>. The output

of the filter is written to B<out>. Any data written to the returned BIO

is automatically translated to a BER format CMS structure.

=head1 NOTES

The BIO returned by this functions behaves like a standard filter BIO. It

supports non blocking I/O. Content is processes and streamed on the fly and not

all held in memory at once: so it is possible to encode very large structures.

After all content has been written through the BIO BIO_flush() must be called

to finalise the structure.

The B<CMS_STREAM> flag must be included in the corresponding B<flags>

parameter of the B<cms> creation function.

After use BIOs should be removed from the filter using BIO_pop() until

the output BIO B<out> is reached.

Any content written through the filter is uses "as-is" and no canonical

translation is performed.

It is possible to chain multiple BIOs to for example create a triple wrapped

signed, enveloped signed structure. In this case it is the applications

responsibility to set the inner content type of any outer CMS_ContentInfo

structures.

Large numbers of small writes through the chain should be avoided as this will

produce an output consisting of lots of OCTET STRING structures. Prepending

a BIO_f_buffer() buffering BIO will prevent this.

=head1 BUGS

There is currently no corresponding inverse BIO: i.e. one which can decode

a CMS structure on the fly.

=head1 RETURN VALUES

BIO_new_CMS() returns a BIO chain when successful or NULL if an error

occurred. The error can be obtained from ERR_get_error(3).

=head1 SEE ALSO

L<ERR_get_error(3)|ERR_get_error(3)>, L<CMS_sign(3)|CMS_sign(3)>,

L<CMS_encrypt(3)|CMS_encrypt(3)>

=head1 HISTORY

BIO_new_CMS() was added to OpenSSL 0.9.9

=cut

=pod

=head1 NAME

CMS_final - finalise a CMS_ContentInfo structure

=head1 SYNOPSIS

 #include <openssl/cms.h>

 int CMS_final(CMS_ContentInfo *cms, BIO *data, BIO *dcont, unsigned int flags);

=head1 DESCRIPTION

CMS_final() finalises the structure B<cms>. It's purpose is to perform any

operations necessary on B<cms> (digest computation for example) and set the

appropriate fields. The parameter B<data> contains the content to be 

processed. The B<dcont> parameter contains a BIO to write content to after

processing: this is only used with detached data and will usually be set to

NULL.

=head1 NOTES

This function will normally be called when the B<CMS_PARTIAL> flag is used. It

should only be used when streaming is not performed because the streaming

I/O functions perform finalisation operations internally.

=head1 RETURN VALUES

CMS_final() returns 1 for success or 0 for failure.

=head1 SEE ALSO

L<ERR_get_error(3)|ERR_get_error(3)>, L<CMS_sign(3)|CMS_sign(3)>,

L<CMS_encrypt(3)|CMS_encrypt(3)>

=head1 HISTORY

CMS_final() was added to OpenSSL 0.9.8

=cut