/* SPDX-License-Identifier: MPL-2.0 */

#include "precompiled.hpp"

#include <stdlib.h>

#include <string.h>

#include <limits>

#include <limits.h>

#include "decoder.hpp"

#include "v1_decoder.hpp"

#include "likely.hpp"

#include "wire.hpp"

#include "err.hpp"

zmq::v1_decoder_t::v1_decoder_t (size_t bufsize_, int64_t maxmsgsize_) :

    decoder_base_t<v1_decoder_t> (bufsize_), _max_msg_size (maxmsgsize_)

{

    int rc = _in_progress.init ();

    errno_assert (rc == 0);

    //  At the beginning, read one byte and go to one_byte_size_ready state.

    next_step (_tmpbuf, 1, &v1_decoder_t::one_byte_size_ready);

}

zmq::v1_decoder_t::~v1_decoder_t ()

{

    const int rc = _in_progress.close ();

    errno_assert (rc == 0);

}

int zmq::v1_decoder_t::one_byte_size_ready (unsigned char const *)

{

    //  First byte of size is read. If it is UCHAR_MAX (0xff) read 8-byte size.

    //  Otherwise allocate the buffer for message data and read the

    //  message data into it.

    if (*_tmpbuf == UCHAR_MAX)

        next_step (_tmpbuf, 8, &v1_decoder_t::eight_byte_size_ready);

    else {

        //  There has to be at least one byte (the flags) in the message).

        if (!*_tmpbuf) {

            errno = EPROTO;

            return -1;

        }

        if (_max_msg_size >= 0

            && static_cast<int64_t> (*_tmpbuf - 1) > _max_msg_size) {

            errno = EMSGSIZE;

            return -1;

        }

        int rc = _in_progress.close ();

        assert (rc == 0);

        rc = _in_progress.init_size (*_tmpbuf - 1);

        if (rc != 0) {

            errno_assert (errno == ENOMEM);

            rc = _in_progress.init ();

            errno_assert (rc == 0);

            errno = ENOMEM;

            return -1;

        }

        next_step (_tmpbuf, 1, &v1_decoder_t::flags_ready);

    }

    return 0;

}

int zmq::v1_decoder_t::eight_byte_size_ready (unsigned char const *)

{

    //  8-byte payload length is read. Allocate the buffer

    //  for message body and read the message data into it.

    const uint64_t payload_length = get_uint64 (_tmpbuf);

    //  There has to be at least one byte (the flags) in the message).

    if (payload_length == 0) {

        errno = EPROTO;

        return -1;

    }

    //  Message size must not exceed the maximum allowed size.

    if (_max_msg_size >= 0

        && payload_length - 1 > static_cast<uint64_t> (_max_msg_size)) {

        errno = EMSGSIZE;

        return -1;

    }

#ifndef __aarch64__

    //  Message size must fit within range of size_t data type.

    if (payload_length - 1 > std::numeric_limits<size_t>::max ()) {

        errno = EMSGSIZE;

        return -1;

    }

#endif

    const size_t msg_size = static_cast<size_t> (payload_length - 1);

    int rc = _in_progress.close ();

    assert (rc == 0);

    rc = _in_progress.init_size (msg_size);

    if (rc != 0) {

        errno_assert (errno == ENOMEM);

        rc = _in_progress.init ();

        errno_assert (rc == 0);

        errno = ENOMEM;

        return -1;

    }

    next_step (_tmpbuf, 1, &v1_decoder_t::flags_ready);

    return 0;

}

int zmq::v1_decoder_t::flags_ready (unsigned char const *)

{

    //  Store the flags from the wire into the message structure.

    _in_progress.set_flags (_tmpbuf[0] & msg_t::more);

    next_step (_in_progress.data (), _in_progress.size (),

               &v1_decoder_t::message_ready);

    return 0;

}

int zmq::v1_decoder_t::message_ready (unsigned char const *)

{

    //  Message is completely read. Push it further and start reading

    //  new message. (in_progress is a 0-byte message after this point.)

    next_step (_tmpbuf, 1, &v1_decoder_t::one_byte_size_ready);

    return 1;

}