libzmq/src/v2_encoder.cpp
Luca Boccassi da31917f4f Relicense from LGPL3 + exceptions to Mozilla Public License version 2.0
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Fixes https://github.com/zeromq/libzmq/issues/2376
2023-06-05 20:31:47 +01:00

70 lines
2.4 KiB
C++

/* SPDX-License-Identifier: MPL-2.0 */
#include "precompiled.hpp"
#include "v2_protocol.hpp"
#include "v2_encoder.hpp"
#include "msg.hpp"
#include "likely.hpp"
#include "wire.hpp"
#include <limits.h>
zmq::v2_encoder_t::v2_encoder_t (size_t bufsize_) :
encoder_base_t<v2_encoder_t> (bufsize_)
{
// Write 0 bytes to the batch and go to message_ready state.
next_step (NULL, 0, &v2_encoder_t::message_ready, true);
}
zmq::v2_encoder_t::~v2_encoder_t ()
{
}
void zmq::v2_encoder_t::message_ready ()
{
// Encode flags.
size_t size = in_progress ()->size ();
size_t header_size = 2; // flags byte + size byte
unsigned char &protocol_flags = _tmp_buf[0];
protocol_flags = 0;
if (in_progress ()->flags () & msg_t::more)
protocol_flags |= v2_protocol_t::more_flag;
if (in_progress ()->size () > UCHAR_MAX)
protocol_flags |= v2_protocol_t::large_flag;
if (in_progress ()->flags () & msg_t::command)
protocol_flags |= v2_protocol_t::command_flag;
if (in_progress ()->is_subscribe () || in_progress ()->is_cancel ())
++size;
// Encode the message length. For messages less then 256 bytes,
// the length is encoded as 8-bit unsigned integer. For larger
// messages, 64-bit unsigned integer in network byte order is used.
if (unlikely (size > UCHAR_MAX)) {
put_uint64 (_tmp_buf + 1, size);
header_size = 9; // flags byte + size 8 bytes
} else {
_tmp_buf[1] = static_cast<uint8_t> (size);
}
// Encode the subscribe/cancel byte. This is done in the encoder as
// opposed to when the subscribe message is created to allow different
// protocol behaviour on the wire in the v3.1 and legacy encoders.
// It results in the work being done multiple times in case the sub
// is sending the subscription/cancel to multiple pubs, but it cannot
// be avoided. This processing can be moved to xsub once support for
// ZMTP < 3.1 is dropped.
if (in_progress ()->is_subscribe ())
_tmp_buf[header_size++] = 1;
else if (in_progress ()->is_cancel ())
_tmp_buf[header_size++] = 0;
next_step (_tmp_buf, header_size, &v2_encoder_t::size_ready, false);
}
void zmq::v2_encoder_t::size_ready ()
{
// Write message body into the buffer.
next_step (in_progress ()->data (), in_progress ()->size (),
&v2_encoder_t::message_ready, true);
}