NS-3 based Named Data Networking (NDN) simulator
ndnSIM: NDN, CCN, CCNx, content centric networks
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wire-ccnb.cc
1 /* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
2 /*
3  * Copyright (c) 2011 University of California, Los Angeles
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation;
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  *
18  * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
19  */
20 
21 #include "wire-ccnb.h"
22 
23 #include <sstream>
24 #include <boost/foreach.hpp>
25 #include "ccnb-parser/common.h"
26 #include "ccnb-parser/visitors/name-visitor.h"
27 #include "ccnb-parser/syntax-tree/block.h"
28 
29 NDN_NAMESPACE_BEGIN
30 
31 namespace wire {
32 
36 
37 #define CCN_TT_BITS 3
38 #define CCN_TT_MASK ((1 << CCN_TT_BITS) - 1)
39 #define CCN_MAX_TINY ((1 << (7-CCN_TT_BITS)) - 1)
40 #define CCN_TT_HBIT ((unsigned char)(1 << 7))
41 
42 size_t
43 Ccnb::AppendBlockHeader (Buffer::Iterator &start, size_t val, uint32_t tt)
44 {
45  unsigned char buf[1+8*((sizeof(val)+6)/7)];
46  unsigned char *p = &(buf[sizeof(buf)-1]);
47  size_t n = 1;
48  p[0] = (CCN_TT_HBIT & ~CcnbParser::CCN_CLOSE) |
49  ((val & CCN_MAX_TINY) << CCN_TT_BITS) |
50  (CCN_TT_MASK & tt);
51  val >>= (7-CCN_TT_BITS);
52  while (val != 0) {
53  (--p)[0] = (((unsigned char)val) & ~CCN_TT_HBIT) | CcnbParser::CCN_CLOSE;
54  n++;
55  val >>= 7;
56  }
57  start.Write (p,n);
58  return n;
59 }
60 
61 size_t
62 Ccnb::EstimateBlockHeader (size_t value)
63 {
64  value >>= (7-CCN_TT_BITS);
65  size_t n = 1;
66  while (value>0)
67  {
68  value >>= 7;
69  n++;
70  }
71  return n;
72 }
73 
74 size_t
75 Ccnb::AppendNumber (Buffer::Iterator &start, uint32_t number)
76 {
77  std::ostringstream os;
78  os << number;
79 
80  size_t written = 0;
81  written += AppendBlockHeader (start, os.str().size(), CcnbParser::CCN_UDATA);
82  written += os.str().size();
83  start.Write (reinterpret_cast<const unsigned char*>(os.str().c_str()), os.str().size());
84 
85  return written;
86 }
87 
88 size_t
89 Ccnb::EstimateNumber (uint32_t number)
90 {
91  std::ostringstream os;
92  os << number;
93  return EstimateBlockHeader (os.str ().size ()) + os.str ().size ();
94 }
95 
96 size_t
97 Ccnb::AppendCloser (Buffer::Iterator &start)
98 {
99  start.WriteU8 (CcnbParser::CCN_CLOSE);
100  return 1;
101 }
102 
103 size_t
104 Ccnb::AppendTimestampBlob (Buffer::Iterator &start, const Time &time)
105 {
106  // the original function implements Markers... thought not sure what are these markers for...
107 
108  // Determine miminal number of bytes required to store the timestamp
109  int required_bytes = 2; // 12 bits for fractions of a second, 4 bits left for seconds. Sometimes it is enough
110  intmax_t ts = time.ToInteger (Time::S) >> 4;
111  for (; required_bytes < 7 && ts != 0; ts >>= 8) // not more than 6 bytes?
112  required_bytes++;
113 
114  size_t len = AppendBlockHeader(start, required_bytes, CcnbParser::CCN_BLOB);
115 
116  // write part with seconds
117  ts = time.ToInteger (Time::S) >> 4;
118  for (int i = 0; i < required_bytes - 2; i++)
119  start.WriteU8 ( ts >> (8 * (required_bytes - 3 - i)) );
120 
121  /* arithmetic contortions are to avoid overflowing 31 bits */
122  ts = ((time.ToInteger (Time::S) & 15) << 12) +
123  (((time.ToInteger (Time::NS) % 1000000000) / 5 * 8 + 195312) / 390625);
124  for (int i = required_bytes - 2; i < required_bytes; i++)
125  start.WriteU8 ( ts >> (8 * (required_bytes - 1 - i)) );
126 
127  return len + required_bytes;
128 }
129 
130 size_t
131 Ccnb::EstimateTimestampBlob (const Time &time)
132 {
133  int required_bytes = 2; // 12 bits for fractions of a second, 4 bits left for seconds. Sometimes it is enough
134  intmax_t ts = time.ToInteger (Time::S) >> 4;
135  for (; required_bytes < 7 && ts != 0; ts >>= 8) // not more than 6 bytes?
136  required_bytes++;
137 
138  return EstimateBlockHeader (required_bytes) + required_bytes;
139 }
140 
141 size_t
142 Ccnb::AppendTaggedBlob (Buffer::Iterator &start, uint32_t dtag,
143  const uint8_t *data, size_t size)
144 {
145  size_t written = AppendBlockHeader (start, dtag, CcnbParser::CCN_DTAG);
146  /* 2 */
147  if (size>0)
148  {
149  written += AppendBlockHeader (start, size, CcnbParser::CCN_BLOB);
150  start.Write (data, size);
151  written += size;
152  /* size */
153  }
154  written += AppendCloser (start);
155  /* 1 */
156 
157  return written;
158 }
159 
160 size_t
161 Ccnb::AppendTaggedBlobWithPadding (Buffer::Iterator &start, uint32_t dtag,
162  uint32_t length,
163  const uint8_t *data, size_t size)
164 {
165  if (size > length)
166  {
167  // no padding required
168  return AppendTaggedBlob (start, dtag, data, size);
169  }
170 
171 
172  size_t written = AppendBlockHeader (start, dtag, CcnbParser::CCN_DTAG);
173 
174  /* 2 */
175  if (length>0)
176  {
177  written += AppendBlockHeader (start, length, CcnbParser::CCN_BLOB);
178  start.Write (data, size);
179  start.WriteU8 (0, length - size);
180  written += length;
181  /* size */
182  }
183  written += AppendCloser (start);
184  /* 1 */
185 
186  return written;
187 }
188 
189 size_t
190 Ccnb::EstimateTaggedBlob (uint32_t dtag, size_t size)
191 {
192  if (size>0)
193  return EstimateBlockHeader (dtag) + EstimateBlockHeader (size) + size + 1;
194  else
195  return EstimateBlockHeader (dtag) + 1;
196 }
197 
198 size_t
199 Ccnb::AppendString (Buffer::Iterator &start, uint32_t dtag,
200  const std::string &string)
201 {
202  size_t written = AppendBlockHeader (start, dtag, CcnbParser::CCN_DTAG);
203  {
204  written += AppendBlockHeader (start, string.size (), CcnbParser::CCN_UDATA);
205  start.Write (reinterpret_cast<const uint8_t*> (string.c_str ()), string.size ());
206  written += string.size ();
207  }
208  written += AppendCloser (start);
209 
210  return written;
211 }
212 
213 size_t
214 Ccnb::EstimateString (uint32_t dtag, const std::string &string)
215 {
216  return EstimateBlockHeader (dtag) + EstimateBlockHeader (string.size ()) + string.size () + 1;
217 }
218 
219 size_t
220 Ccnb::SerializeName (Buffer::Iterator &start, const Name &name)
221 {
222  size_t written = 0;
223  written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_Name, CcnbParser::CCN_DTAG);
224  BOOST_FOREACH (const name::Component &component, name)
225  {
226  written += AppendTaggedBlob (start, CcnbParser::CCN_DTAG_Component,
227  reinterpret_cast<const uint8_t*>(component.buf ()), component.size());
228  }
229  written += AppendCloser (start);
230  return written;
231 }
232 
233 size_t
234 Ccnb::SerializedSizeName (const Name &name)
235 {
236  size_t written = 0;
237  written += EstimateBlockHeader (CcnbParser::CCN_DTAG_Name);
238  BOOST_FOREACH (const name::Component &component, name)
239  {
240  written += EstimateTaggedBlob (CcnbParser::CCN_DTAG_Component, component.size ());
241  }
242  written += 1;
243  return written;
244 }
245 
246 Ptr<Name>
247 Ccnb::DeserializeName (Buffer::Iterator &i)
248 {
249  Ptr<Name> name = Create<Name> ();
250  CcnbParser::NameVisitor nameVisitor;
251 
252  Ptr<CcnbParser::Block> root = CcnbParser::Block::ParseBlock (i);
253  root->accept (nameVisitor, GetPointer (name));
254 
255  return name;
256 }
257 
258 } // wire
259 
260 NDN_NAMESPACE_END
Class for NDN Name.
Definition: name.h:29
char * buf()
Get pointer to the first byte of the binary blob.
Definition: blob.h:66
Visitor to obtain fill CcnxName object with name components.
Definition: name-visitor.h:35
Class to representing binary blob of NDN name component.