Struct sequoia_openpgp::serialize::stream::padding::Padder [−][src]
pub struct Padder<'a> { /* fields omitted */ }
Expand description
Pads a packet stream.
Writes a compressed data packet containing all packets written to this writer, and pads it according to the given policy.
The policy is a Fn(u64) -> u64
, that given the number of bytes
written to this writer N
, computes the size the compression
container should be padded up to. It is an error to return a
number that is smaller than N
.
Compatibility
This implementation uses the DEFLATE compression format. The packet structure contains a flag signaling the end of the stream (see Section 3.2.3 of RFC 1951), and any data appended after that is not part of the stream.
Section 9.3 of RFC 4880 recommends that this algorithm should be implemented, therefore support across various implementations should be good.
Examples
This example illustrates the use of Padder
with the Padmé
policy. Note that for brevity, the encryption and signature
filters are omitted.
use std::io::Write;
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::{Message, LiteralWriter};
use openpgp::serialize::stream::padding::Padder;
use openpgp::types::CompressionAlgorithm;
let mut unpadded = vec![];
{
let message = Message::new(&mut unpadded);
// XXX: Insert Encryptor here.
// XXX: Insert Signer here.
let mut message = LiteralWriter::new(message).build()?;
message.write_all(b"Hello world.")?;
message.finalize()?;
}
let mut padded = vec![];
{
let message = Message::new(&mut padded);
// XXX: Insert Encryptor here.
let message = Padder::new(message).build()?;
// XXX: Insert Signer here.
let mut message = LiteralWriter::new(message).build()?;
message.write_all(b"Hello world.")?;
message.finalize()?;
}
assert!(unpadded.len() < padded.len());
Implementations
Creates a new padder with the given policy.
Examples
This example illustrates the use of Padder
with the Padmé
policy.
The most useful filter to push to the writer stack next is the
Signer
or the LiteralWriter
. Finally, literal data
must be wrapped using the LiteralWriter
.
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::padding::Padder;
let message = Padder::new(message).build()?;
// Optionally add a `Signer` here.
// Add a `LiteralWriter` here.
Sets padding policy, returning the padder.
Examples
This example illustrates the use of Padder
with an explicit policy.
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::padding::{Padder, padme};
let message = Padder::new(message).with_policy(padme).build()?;
// Optionally add a `Signer` here.
// Add a `LiteralWriter` here.
Builds the padder, returning the writer stack.
Examples
This example illustrates the use of Padder
with the Padmé
policy.
The most useful filter to push to the writer stack next is the
Signer
or the LiteralWriter
. Finally, literal data
must be wrapped using the LiteralWriter
.
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::padding::Padder;
let message = Padder::new(message).build()?;
// Optionally add a `Signer` here.
// Add a `LiteralWriter` here.
Trait Implementations
Write a buffer into this writer, returning how many bytes were written. Read more
Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
can_vector
)Determines if this Write
r has an efficient write_vectored
implementation. Read more
Attempts to write an entire buffer into this writer. Read more
write_all_vectored
)Attempts to write multiple buffers into this writer. Read more
Writes a formatted string into this writer, returning any error encountered. Read more