tcpflow  1.6.1
About: tcpflow is a TCP/IP packet demultiplexer that captures data transmitted as part of TCP connections (flows), and stores the data in a way that is convenient for protocol analysis and debugging.
  Fossies Dox: tcpflow-1.6.1.tar.gz  ("unofficial" and yet experimental doxygen-generated source code documentation)  

core.h
Go to the documentation of this file.
1 // Copyright 2006 Nemanja Trifunovic
2 
3 /*
4 Permission is hereby granted, free of charge, to any person or organization
5 obtaining a copy of the software and accompanying documentation covered by
6 this license (the "Software") to use, reproduce, display, distribute,
7 execute, and transmit the Software, and to prepare derivative works of the
8 Software, and to permit third-parties to whom the Software is furnished to
9 do so, all subject to the following:
10 
11 The copyright notices in the Software and this entire statement, including
12 the above license grant, this restriction and the following disclaimer,
13 must be included in all copies of the Software, in whole or in part, and
14 all derivative works of the Software, unless such copies or derivative
15 works are solely in the form of machine-executable object code generated by
16 a source language processor.
17 
18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
21 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
22 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
23 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
24 DEALINGS IN THE SOFTWARE.
25 */
26 
27 
28 #ifndef UTF8_FOR_CPP_CORE_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
29 #define UTF8_FOR_CPP_CORE_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
30 
31 #include <iterator>
32 
33 namespace utf8
34 {
35  // The typedefs for 8-bit, 16-bit and 32-bit unsigned integers
36  // You may need to change them to match your system.
37  // These typedefs have the same names as ones from cstdint, or boost/cstdint
38  typedef unsigned char uint8_t;
39  typedef unsigned short uint16_t;
40  typedef unsigned int uint32_t;
41 
42 // Helper code - not intended to be directly called by the library users. May be changed at any time
43 namespace internal
44 {
45  // Unicode constants
46  // Leading (high) surrogates: 0xd800 - 0xdbff
47  // Trailing (low) surrogates: 0xdc00 - 0xdfff
48  const uint16_t LEAD_SURROGATE_MIN = 0xd800u;
49  const uint16_t LEAD_SURROGATE_MAX = 0xdbffu;
50  const uint16_t TRAIL_SURROGATE_MIN = 0xdc00u;
51  const uint16_t TRAIL_SURROGATE_MAX = 0xdfffu;
52  const uint16_t LEAD_OFFSET = LEAD_SURROGATE_MIN - (0x10000 >> 10);
54 
55  // Maximum valid value for a Unicode code point
56  const uint32_t CODE_POINT_MAX = 0x0010ffffu;
57 
58  template<typename octet_type>
59  inline uint8_t mask8(octet_type oc)
60  {
61  return static_cast<uint8_t>(0xff & oc);
62  }
63  template<typename u16_type>
64  inline uint16_t mask16(u16_type oc)
65  {
66  return static_cast<uint16_t>(0xffff & oc);
67  }
68  template<typename octet_type>
69  inline bool is_trail(octet_type oc)
70  {
71  return ((mask8(oc) >> 6) == 0x2);
72  }
73 
74  template <typename u16>
75  inline bool is_lead_surrogate(u16 cp)
76  {
77  return (cp >= LEAD_SURROGATE_MIN && cp <= LEAD_SURROGATE_MAX);
78  }
79 
80  template <typename u16>
81  inline bool is_trail_surrogate(u16 cp)
82  {
83  return (cp >= TRAIL_SURROGATE_MIN && cp <= TRAIL_SURROGATE_MAX);
84  }
85 
86  template <typename u16>
87  inline bool is_surrogate(u16 cp)
88  {
89  return (cp >= LEAD_SURROGATE_MIN && cp <= TRAIL_SURROGATE_MAX);
90  }
91 
92  template <typename u32>
93  inline bool is_code_point_valid(u32 cp)
94  {
95  return (cp <= CODE_POINT_MAX && !is_surrogate(cp));
96  }
97 
98  template <typename octet_iterator>
99  inline typename std::iterator_traits<octet_iterator>::difference_type
100  sequence_length(octet_iterator lead_it)
101  {
102  uint8_t lead = mask8(*lead_it);
103  if (lead < 0x80)
104  return 1;
105  else if ((lead >> 5) == 0x6)
106  return 2;
107  else if ((lead >> 4) == 0xe)
108  return 3;
109  else if ((lead >> 3) == 0x1e)
110  return 4;
111  else
112  return 0;
113  }
114 
115  template <typename octet_difference_type>
116  inline bool is_overlong_sequence(uint32_t cp, octet_difference_type length)
117  {
118  if (cp < 0x80) {
119  if (length != 1)
120  return true;
121  }
122  else if (cp < 0x800) {
123  if (length != 2)
124  return true;
125  }
126  else if (cp < 0x10000) {
127  if (length != 3)
128  return true;
129  }
130 
131  return false;
132  }
133 
135 
136  /// get_sequence_x functions decode utf-8 sequences of the length x
137 
138  template <typename octet_iterator>
139  utf_error get_sequence_1(octet_iterator& it, octet_iterator end, uint32_t* code_point)
140  {
141  if (it != end) {
142  if (code_point)
143  *code_point = mask8(*it);
144  return UTF8_OK;
145  }
146  return NOT_ENOUGH_ROOM;
147  }
148 
149  template <typename octet_iterator>
150  utf_error get_sequence_2(octet_iterator& it, octet_iterator end, uint32_t* code_point)
151  {
152  utf_error ret_code = NOT_ENOUGH_ROOM;
153 
154  if (it != end) {
155  uint32_t cp = mask8(*it);
156  if (++it != end) {
157  if (is_trail(*it)) {
158  cp = ((cp << 6) & 0x7ff) + ((*it) & 0x3f);
159 
160  if (code_point)
161  *code_point = cp;
162  ret_code = UTF8_OK;
163  }
164  else
165  ret_code = INCOMPLETE_SEQUENCE;
166  }
167  else
168  ret_code = NOT_ENOUGH_ROOM;
169  }
170 
171  return ret_code;
172  }
173 
174  template <typename octet_iterator>
175  utf_error get_sequence_3(octet_iterator& it, octet_iterator end, uint32_t* code_point)
176  {
177  utf_error ret_code = NOT_ENOUGH_ROOM;
178 
179  if (it != end) {
180  uint32_t cp = mask8(*it);
181  if (++it != end) {
182  if (is_trail(*it)) {
183  cp = ((cp << 12) & 0xffff) + ((mask8(*it) << 6) & 0xfff);
184  if (++it != end) {
185  if (is_trail(*it)) {
186  cp += (*it) & 0x3f;
187 
188  if (code_point)
189  *code_point = cp;
190  ret_code = UTF8_OK;
191  }
192  else
193  ret_code = INCOMPLETE_SEQUENCE;
194  }
195  else
196  ret_code = NOT_ENOUGH_ROOM;
197  }
198  else
199  ret_code = INCOMPLETE_SEQUENCE;
200  }
201  else
202  ret_code = NOT_ENOUGH_ROOM;
203  }
204 
205  return ret_code;
206  }
207 
208  template <typename octet_iterator>
209  utf_error get_sequence_4(octet_iterator& it, octet_iterator end, uint32_t* code_point)
210  {
211  utf_error ret_code = NOT_ENOUGH_ROOM;
212 
213  if (it != end) {
214  uint32_t cp = mask8(*it);
215  if (++it != end) {
216  if (is_trail(*it)) {
217  cp = ((cp << 18) & 0x1fffff) + ((mask8(*it) << 12) & 0x3ffff);
218  if (++it != end) {
219  if (is_trail(*it)) {
220  cp += (mask8(*it) << 6) & 0xfff;
221  if (++it != end) {
222  if (is_trail(*it)) {
223  cp += (*it) & 0x3f;
224 
225  if (code_point)
226  *code_point = cp;
227  ret_code = UTF8_OK;
228  }
229  else
230  ret_code = INCOMPLETE_SEQUENCE;
231  }
232  else
233  ret_code = NOT_ENOUGH_ROOM;
234  }
235  else
236  ret_code = INCOMPLETE_SEQUENCE;
237  }
238  else
239  ret_code = NOT_ENOUGH_ROOM;
240  }
241  else
242  ret_code = INCOMPLETE_SEQUENCE;
243  }
244  else
245  ret_code = NOT_ENOUGH_ROOM;
246  }
247 
248  return ret_code;
249  }
250 
251  template <typename octet_iterator>
252  utf_error validate_next(octet_iterator& it, octet_iterator end, uint32_t* code_point)
253  {
254  // Save the original value of it so we can go back in case of failure
255  // Of course, it does not make much sense with i.e. stream iterators
256  octet_iterator original_it = it;
257 
258  uint32_t cp = 0;
259  // Determine the sequence length based on the lead octet
260  typedef typename std::iterator_traits<octet_iterator>::difference_type octet_difference_type;
261  octet_difference_type length = sequence_length(it);
262  if (length == 0)
263  return INVALID_LEAD;
264 
265  // Now that we have a valid sequence length, get trail octets and calculate the code point
267  switch (length) {
268  case 1:
269  err = get_sequence_1(it, end, &cp);
270  break;
271  case 2:
272  err = get_sequence_2(it, end, &cp);
273  break;
274  case 3:
275  err = get_sequence_3(it, end, &cp);
276  break;
277  case 4:
278  err = get_sequence_4(it, end, &cp);
279  break;
280  }
281 
282  if (err == UTF8_OK) {
283  // Decoding succeeded. Now, security checks...
284  if (is_code_point_valid(cp)) {
285  if (!is_overlong_sequence(cp, length)){
286  // Passed! Return here.
287  if (code_point)
288  *code_point = cp;
289  ++it;
290  return UTF8_OK;
291  }
292  else
294  }
295  else
297  }
298 
299  // Failure branch - restore the original value of the iterator
300  it = original_it;
301  return err;
302  }
303 
304  template <typename octet_iterator>
305  inline utf_error validate_next(octet_iterator& it, octet_iterator end) {
306  return validate_next(it, end, 0);
307  }
308 
309 } // namespace internal
310 
311  /// The library API - functions intended to be called by the users
312 
313  // Byte order mark
314  const uint8_t bom[] = {0xef, 0xbb, 0xbf};
315 
316  template <typename octet_iterator>
317  octet_iterator find_invalid(octet_iterator start, octet_iterator end)
318  {
319  octet_iterator result = start;
320  while (result != end) {
321  internal::utf_error err_code = internal::validate_next(result, end);
322  if (err_code != internal::UTF8_OK)
323  return result;
324  }
325  return result;
326  }
327 
328  template <typename octet_iterator>
329  inline bool is_valid(octet_iterator start, octet_iterator end)
330  {
331  return (find_invalid(start, end) == end);
332  }
333 
334  template <typename octet_iterator>
335  inline bool starts_with_bom (octet_iterator it, octet_iterator end)
336  {
337  return (
338  ((it != end) && (internal::mask8(*it++)) == bom[0]) &&
339  ((it != end) && (internal::mask8(*it++)) == bom[1]) &&
340  ((it != end) && (internal::mask8(*it)) == bom[2])
341  );
342  }
343 
344  //Deprecated in release 2.3
345  template <typename octet_iterator>
346  inline bool is_bom (octet_iterator it)
347  {
348  return (
349  (internal::mask8(*it++)) == bom[0] &&
350  (internal::mask8(*it++)) == bom[1] &&
351  (internal::mask8(*it)) == bom[2]
352  );
353  }
354 } // namespace utf8
355 
356 #endif // header guard
357 
358 
const uint32_t CODE_POINT_MAX
Definition: core.h:56
bool is_lead_surrogate(u16 cp)
Definition: core.h:75
utf_error get_sequence_4(octet_iterator &it, octet_iterator end, uint32_t *code_point)
Definition: core.h:209
bool is_trail_surrogate(u16 cp)
Definition: core.h:81
bool is_overlong_sequence(uint32_t cp, octet_difference_type length)
Definition: core.h:116
bool is_surrogate(u16 cp)
Definition: core.h:87
const uint32_t SURROGATE_OFFSET
Definition: core.h:53
const uint16_t TRAIL_SURROGATE_MAX
Definition: core.h:51
const uint16_t LEAD_OFFSET
Definition: core.h:52
utf_error get_sequence_2(octet_iterator &it, octet_iterator end, uint32_t *code_point)
Definition: core.h:150
const uint16_t TRAIL_SURROGATE_MIN
Definition: core.h:50
utf_error get_sequence_3(octet_iterator &it, octet_iterator end, uint32_t *code_point)
Definition: core.h:175
bool is_code_point_valid(u32 cp)
Definition: core.h:93
@ INCOMPLETE_SEQUENCE
Definition: core.h:134
@ INVALID_LEAD
Definition: core.h:134
@ OVERLONG_SEQUENCE
Definition: core.h:134
@ INVALID_CODE_POINT
Definition: core.h:134
@ NOT_ENOUGH_ROOM
Definition: core.h:134
std::iterator_traits< octet_iterator >::difference_type sequence_length(octet_iterator lead_it)
Definition: core.h:100
uint16_t mask16(u16_type oc)
Definition: core.h:64
bool is_trail(octet_type oc)
Definition: core.h:69
const uint16_t LEAD_SURROGATE_MIN
Definition: core.h:48
utf_error validate_next(octet_iterator &it, octet_iterator end, uint32_t *code_point)
Definition: core.h:252
uint8_t mask8(octet_type oc)
Definition: core.h:59
utf_error get_sequence_1(octet_iterator &it, octet_iterator end, uint32_t *code_point)
get_sequence_x functions decode utf-8 sequences of the length x
Definition: core.h:139
const uint16_t LEAD_SURROGATE_MAX
Definition: core.h:49
Definition: checked.h:35
bool starts_with_bom(octet_iterator it, octet_iterator end)
Definition: core.h:335
unsigned int uint32_t
Definition: core.h:40
unsigned char uint8_t
Definition: core.h:38
unsigned short uint16_t
Definition: core.h:39
const uint8_t bom[]
The library API - functions intended to be called by the users.
Definition: core.h:314
bool is_valid(octet_iterator start, octet_iterator end)
Definition: core.h:329
octet_iterator find_invalid(octet_iterator start, octet_iterator end)
Definition: core.h:317
bool is_bom(octet_iterator it)
Definition: core.h:346
void err(int eval, const char *fmt,...)
Definition: utils.cpp:33