emissary-core 0.4.0

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//
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use crate::i2cp::message::{MessageType, I2CP_HEADER_SIZE};

use bytes::{BufMut, BytesMut};

use alloc::vec::Vec;

/// `MessagePayload` message.
///
/// https://geti2p.net/spec/i2cp#messagepayloadmessage
pub struct MessagePayload(());

impl MessagePayload {
    /// Create new `MessagePayload` message.
    pub fn new(session_id: u16, message_id: u32, message: Vec<u8>) -> BytesMut {
        let payload_len = 2usize // session id
            + 4usize // message id
            + 4usize // payload size
            + message.len();

        let mut out = BytesMut::with_capacity(I2CP_HEADER_SIZE + payload_len);

        out.put_u32(payload_len as u32);
        out.put_u8(MessageType::MessagePayload.as_u8());
        out.put_u16(session_id);
        out.put_u32(message_id);
        out.put_u32(message.len() as u32);
        out.put_slice(&message);

        out
    }
}