v1_decoder.cpp 4.8 KB
Newer Older
1
/*
2
    Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
3

4
    This file is part of libzmq, the ZeroMQ core engine in C++.
5

6 7 8
    libzmq is free software; you can redistribute it and/or modify it under
    the terms of the GNU Lesser General Public License (LGPL) as published
    by the Free Software Foundation; either version 3 of the License, or
9 10
    (at your option) any later version.

11 12 13 14 15 16 17 18 19 20 21 22 23 24
    As a special exception, the Contributors give you permission to link
    this library with independent modules to produce an executable,
    regardless of the license terms of these independent modules, and to
    copy and distribute the resulting executable under terms of your choice,
    provided that you also meet, for each linked independent module, the
    terms and conditions of the license of that module. An independent
    module is a module which is not derived from or based on this library.
    If you modify this library, you must extend this exception to your
    version of the library.

    libzmq is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
    License for more details.
25 26 27 28 29

    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

30
#include "precompiled.hpp"
31 32
#include <stdlib.h>
#include <string.h>
33
#include <limits>
34

35
#include "decoder.hpp"
36 37 38 39 40
#include "v1_decoder.hpp"
#include "likely.hpp"
#include "wire.hpp"
#include "err.hpp"

41
zmq::v1_decoder_t::v1_decoder_t (size_t bufsize_, int64_t maxmsgsize_) :
42 43
    c_single_allocator (bufsize_),
    decoder_base_t<v1_decoder_t> (this),
44 45 46 47 48
    maxmsgsize (maxmsgsize_)
{
    int rc = in_progress.init ();
    errno_assert (rc == 0);

49 50
    //  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);
51 52 53 54 55 56 57 58
}

zmq::v1_decoder_t::~v1_decoder_t ()
{
    int rc = in_progress.close ();
    errno_assert (rc == 0);
}

59
int zmq::v1_decoder_t::one_byte_size_ready (unsigned char const *)
60
{
61 62 63 64 65 66 67 68
    //  First byte of size is read. If it is 0xff read 8-byte size.
    //  Otherwise allocate the buffer for message data and read the
    //  message data into it.
    if (*tmpbuf == 0xff)
        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) {
69 70 71 72 73 74 75
            errno = EPROTO;
            return -1;
        }

        if (maxmsgsize >= 0 && (int64_t) (*tmpbuf - 1) > maxmsgsize) {
            errno = EMSGSIZE;
            return -1;
76 77
        }

78 79
        int rc = in_progress.close ();
        assert (rc == 0);
80
        rc = in_progress.init_size (*tmpbuf - 1);
81 82
        if (rc != 0) {
            errno_assert (errno == ENOMEM);
83 84
            rc = in_progress.init ();
            errno_assert (rc == 0);
85 86
            errno = ENOMEM;
            return -1;
87
        }
88

89 90
        next_step (tmpbuf, 1, &v1_decoder_t::flags_ready);
    }
91
    return 0;
92 93
}

94
int zmq::v1_decoder_t::eight_byte_size_ready (unsigned char const *)
95
{
96 97 98
    //  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);
99

100 101
    //  There has to be at least one byte (the flags) in the message).
    if (payload_length == 0) {
102 103
        errno = EPROTO;
        return -1;
104
    }
105 106

    //  Message size must not exceed the maximum allowed size.
107
    if (maxmsgsize >= 0 && payload_length - 1 > (uint64_t) maxmsgsize) {
108 109
        errno = EMSGSIZE;
        return -1;
110
    }
111

112
    //  Message size must fit within range of size_t data type.
113
    if (payload_length - 1 > std::numeric_limits<size_t>::max ()) {
114 115
        errno = EMSGSIZE;
        return -1;
116 117
    }

118
    const size_t msg_size = static_cast<size_t> (payload_length - 1);
119

120 121
    int rc = in_progress.close ();
    assert (rc == 0);
122
    rc = in_progress.init_size (msg_size);
123
    if (rc != 0) {
124
        errno_assert (errno == ENOMEM);
125
        rc = in_progress.init ();
126
        errno_assert (rc == 0);
127 128
        errno = ENOMEM;
        return -1;
129 130
    }

131
    next_step (tmpbuf, 1, &v1_decoder_t::flags_ready);
132
    return 0;
133 134
}

135
int zmq::v1_decoder_t::flags_ready (unsigned char const *)
136 137
{
    //  Store the flags from the wire into the message structure.
138
    in_progress.set_flags (tmpbuf[0] & msg_t::more);
139

140
    next_step (in_progress.data (), in_progress.size (),
141
               &v1_decoder_t::message_ready);
142

143
    return 0;
144 145
}

146
int zmq::v1_decoder_t::message_ready (unsigned char const *)
147 148 149
{
    //  Message is completely read. Push it further and start reading
    //  new message. (in_progress is a 0-byte message after this point.)
150
    next_step (tmpbuf, 1, &v1_decoder_t::one_byte_size_ready);
151
    return 1;
152
}