1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
/*
Copyright (c) 2007-2011 iMatix Corporation
Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
This file is part of 0MQ.
0MQ is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
0MQ 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.
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/>.
*/
#ifndef __ZMQ_ENCODER_HPP_INCLUDED__
#define __ZMQ_ENCODER_HPP_INCLUDED__
#include <stddef.h>
#include <string.h>
#include <stdlib.h>
#include <algorithm>
#include "err.hpp"
#include "../include/zmq.h"
namespace zmq
{
// Helper base class for encoders. It implements the state machine that
// fills the outgoing buffer. Derived classes should implement individual
// state machine actions.
template <typename T> class encoder_base_t
{
public:
inline encoder_base_t (size_t bufsize_) :
bufsize (bufsize_)
{
buf = (unsigned char*) malloc (bufsize_);
alloc_assert (buf);
}
// The destructor doesn't have to be virtual. It is made virtual
// just to keep ICC and code checking tools from complaining.
inline virtual ~encoder_base_t ()
{
free (buf);
}
// The function returns a batch of binary data. The data
// are filled to a supplied buffer. If no buffer is supplied (data_
// points to NULL) decoder object will provide buffer of its own.
// If offset is not NULL, it is filled by offset of the first message
// in the batch.If there's no beginning of a message in the batch,
// offset is set to -1.
inline void get_data (unsigned char **data_, size_t *size_,
int *offset_ = NULL)
{
unsigned char *buffer = !*data_ ? buf : *data_;
size_t buffersize = !*data_ ? bufsize : *size_;
size_t pos = 0;
if (offset_)
*offset_ = -1;
while (true) {
// If there are no more data to return, run the state machine.
// If there are still no data, return what we already have
// in the buffer.
if (!to_write) {
if (!(static_cast <T*> (this)->*next) ()) {
*data_ = buffer;
*size_ = pos;
return;
}
// If beginning of the message was processed, adjust the
// first-message-offset.
if (beginning) {
if (offset_ && *offset_ == -1)
*offset_ = pos;
beginning = false;
}
}
// If there are no data in the buffer yet and we are able to
// fill whole buffer in a single go, let's use zero-copy.
// There's no disadvantage to it as we cannot stuck multiple
// messages into the buffer anyway. Note that subsequent
// write(s) are non-blocking, thus each single write writes
// at most SO_SNDBUF bytes at once not depending on how large
// is the chunk returned from here.
// As a consequence, large messages being sent won't block
// other engines running in the same I/O thread for excessive
// amounts of time.
if (!pos && !*data_ && to_write >= buffersize) {
*data_ = write_pos;
*size_ = to_write;
write_pos = NULL;
to_write = 0;
return;
}
// Copy data to the buffer. If the buffer is full, return.
size_t to_copy = std::min (to_write, buffersize - pos);
memcpy (buffer + pos, write_pos, to_copy);
pos += to_copy;
write_pos += to_copy;
to_write -= to_copy;
if (pos == buffersize) {
*data_ = buffer;
*size_ = pos;
return;
}
}
}
protected:
// Prototype of state machine action.
typedef bool (T::*step_t) ();
// This function should be called from derived class to write the data
// to the buffer and schedule next state machine action. Set beginning
// to true when you are writing first byte of a message.
inline void next_step (void *write_pos_, size_t to_write_,
step_t next_, bool beginning_)
{
write_pos = (unsigned char*) write_pos_;
to_write = to_write_;
next = next_;
beginning = beginning_;
}
private:
unsigned char *write_pos;
size_t to_write;
step_t next;
bool beginning;
size_t bufsize;
unsigned char *buf;
encoder_base_t (const encoder_base_t&);
void operator = (const encoder_base_t&);
};
// Encoder for 0MQ framing protocol. Converts messages into data batches.
class encoder_t : public encoder_base_t <encoder_t>
{
public:
encoder_t (size_t bufsize_);
~encoder_t ();
void set_inout (struct i_inout *source_);
private:
bool size_ready ();
bool message_ready ();
struct i_inout *source;
::zmq_msg_t in_progress;
unsigned char tmpbuf [10];
encoder_t (const encoder_t&);
const encoder_t &operator = (const encoder_t&);
};
}
#endif
|
