summaryrefslogtreecommitdiff
path: root/support/dktools/dk4bom.ctr
blob: 04442f3141fae53ab0a637b2870c194fbc305d90 (plain)
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
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
%%	options

copyright owner	=	Dirk Krause
copyright year	=	2015-xxxx
license		=	bsd



%%	header

/**	@file
	Detect BOM (byte order marker) at start
	of data stream, keep track of unprocessed characters.

	First, use dk4bom_detect_init() to initialize the state machine.

	Now use dk4bom_detect_add() to add the data streams contents
	byte by byte to the state machine as long as the dk4bom_detect_add()
	function returns DK4_EDSTM_ACCEPT.
	If the function returns DK4_EDSTM_ERROR, an error occured, you
	should stop processing.
	If the function returns DK4_EDSTM_FINISHED or
	DK4_EDSTM_FINISHED_WITH_UNUSED a BOM was found or definitely not
	found. Use dk4bom_detect_get_encoding() to obtain the decoding
	found and process the remaining data stream in that encoding.
	If the function returned DK4_EDSTM_FINISHED_WITH_UNUSED, use
	dk4bom_detect_num_unused_bytes() to find the number of unused
	bytes saved in the detector and dk4bom_detect_unused_byte()
	to retrieve and process the unused bytes before processing the
	remaining bytes from the data stream.
	
	For a very short data stream, the detection may not be finished
	at the end of the stream. Use dk4bom_detect_in_detection() to
	find out whether the detection was not yet finished.
	If the function returns 1, the detection is not finished and unused
	bytes are stored in the detector. Use dk4bom_detect_num_unused_bytes()
	and dk4bom_detect_unused_byte() to obtain the unused bytes.

	CRT on Windows: Not used.
*/


#ifndef DK4CONF_H_INCLUDED
#include "dk4conf.h"
#endif

#ifndef DK4TYPES_H_INCLUDED
#include "dk4types.h"
#endif

#ifndef DK4EDSTM_H_INCLUDED
#include "dk4edstm.h"
#endif

#if DK4_HAVE_SYS_TYPES_H
#ifndef SYS_TYPES_H_INCLUDED
#include <sys/types.h>
#define SYS_TYPES_H_INCLUDED 1
#endif
#endif


/**	State machine to detect a BOM (byte order marker)
	at the beginning of a data stream.
*/
typedef struct {
  int		defenc;	/**< Default encoding, used if no BOM detected. */
  int		found;	/**< Encoding from the BOM found. */
  int		state;	/**< Current state of BOM detection. */
  size_t	rjb;	/**< Number of unused bytes. */
  unsigned char	c1;	/**< Rejected byte 1. */
  unsigned char c2;	/**< Rejected byte 2. */
  unsigned char	c3;	/**< Rejected byte 3. */
  unsigned char	c4;	/**< Rejected byte 4. */
} dk4_bom_detector_t;



#ifdef __cplusplus
extern "C" {
#endif

/**	Initialize the BOM detector.
	@param	ptr	BOM detector to initialize.
	@param	defenc	Encoding to use if not BOM at beginning of data.
*/
void
dk4bom_detect_init(dk4_bom_detector_t *ptr, int defenc);

/**	Add one byte to the BOM detector.
	@param	ptr	Detector to use.
	@param	byte	The data byte to add.
	@return	Operation result, one from:
	DK4_EDSTM_ACCEPT if you can continue feeding bytes into the
	detector,
	DK4_EDSTM_FINISHED if a BOM was detected (do not feed further
	bytes),
	DK4_EDSTM_FINISHED_WITH_UNUSED if BOM detection was finished and there
	are unused bytes stored in the detector), or
	DK4_EDSTM_ERROR if you attempt to add further bytes after the
	detection was finished.
	On DK4_EDSTM_FINISHED and DK4_EDSTM_FINISHED_WITH_UNUSED you can use
	dk4bom_detect_get_encoding() to retrieve the encoding.
	On DK4_EDSTM_FINISHED_WITH_UNUSED use dk4bom_detect_num_unused_bytes()
	and dk4bom_detect_unused_byte() to retrieve the unused
	bytes from the detector and process them before processing
	further data from the data stream.
*/
int
dk4bom_detect_add(dk4_bom_detector_t *ptr, unsigned char byte);

/**	Retrieve the encoding from the detector.
	@param	ptr	Detector to use.
	@return	A file encoding, one from: DK4_FILE_ENCODING_ASCII,
	DK4_FILE_ENCODING_ANSI, DK4_FILE_ENCODING_UTF8,
	DK4_FILE_ENCODING_UTF16_LE, DK4_FILE_ENCODING_UTF16_BE,
	DK4_FILE_ENCODING_32_LE, or DK4_FILE_ENCODING_32_BE.
*/
int
dk4bom_detect_get_encoding(dk4_bom_detector_t *ptr);

/**	Retrieve the number of cted bytes stored in the detector.
	@param	ptr	Detector to use.
	@return	Number of unused bytes stored in the detector.
*/
size_t
dk4bom_detect_num_unused_bytes(dk4_bom_detector_t *ptr);

/**	Retrieve one unused byte stored in the detector.
	@param	ptr	Detector to use.
	@param	num	Byte number.
	@return	The byte value.
*/
unsigned char
dk4bom_detect_unused_byte(dk4_bom_detector_t *ptr, size_t num);

/**	Check if BOM detection is still in progress.
	@param	ptr	Detector to check.
	@return	1 if detection is in progress and bytes are
	stored in the detector, 0 otherwise.
*/
int
dk4bom_detect_in_detection(dk4_bom_detector_t *ptr);

#ifdef __cplusplus
}
#endif



%%	module



#include "dk4conf.h"
#include "dk4types.h"
#include "dk4enc.h"
#include "dk4bom.h"



$!trace-include



void
dk4bom_detect_init(dk4_bom_detector_t *ptr, int defenc)
{
  if (NULL != ptr) {
    ptr->defenc = defenc;
    ptr->found  = defenc;
    ptr->state  = 0;
    ptr->rjb    = 0;
    ptr->c1     = 0x00;
    ptr->c2     = 0x00;
    ptr->c3	= 0x00;
  }
}



/*
	BOMS and states
	---------------
	UTF-32 LSB:	0xFF (1) 0xFE (2) 0x00 (3) 0x00
	UTF-32 MSB:	0x00 (4) 0x00 (5) 0xFE (6) 0xFF
	UTF-16 LSB:	0xFF (1) 0xFE (2)
	UTF-16 MSB:	0xFE (7) 0xFF
	UTF-8:		0xEF (8) 0xBB (9) 0xBF
*/



int
dk4bom_detect_add(dk4_bom_detector_t *ptr, unsigned char byte)
{
  int		back	=	DK4_EDSTM_ERROR;
  if (NULL != ptr) {
    switch (ptr->state) {
      case 0: {
	ptr->c1 = byte;
	ptr->rjb = 1;
	switch ( (int)byte ) {
	  case 0x00: {
	    ptr->state = 4; back = DK4_EDSTM_ACCEPT;
	  } break;
	  case 0xFF: {
	    ptr->state = 1; back = DK4_EDSTM_ACCEPT;
	  } break;
	  case 0xFE: {
	    ptr->state = 7; back = DK4_EDSTM_ACCEPT;
	  } break;
	  case 0xEF: {
	    ptr->state = 8; back = DK4_EDSTM_ACCEPT;
	  } break;
	  default: {
	    ptr->state = -1; back = DK4_EDSTM_FINISHED_WITH_UNUSED;
	  } break;
	}
      } break;
      case 1: {
        ptr->c2 = byte;
	ptr->rjb = 2;
        if (0xFE == byte) {
	  ptr->state = 2; back = DK4_EDSTM_ACCEPT;
	  ptr->found = DK4_FILE_ENCODING_UTF16_LE;
	  ptr->rjb = 0;
	} else {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED_WITH_UNUSED;
	}
      } break;
      case 2: {
        ptr->c1 = byte;
	ptr->rjb = 1;
        if (0x00 == byte) {
	  ptr->state = 3; back = DK4_EDSTM_ACCEPT;
	} else {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED_WITH_UNUSED;
	  ptr->found = DK4_FILE_ENCODING_UTF16_LE;
	}
      } break;
      case 3: {
        ptr->c2 = byte;
	ptr->rjb = 2;
        if (0x00 == byte) {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED;
	  ptr->found = DK4_FILE_ENCODING_32_LE;
	  ptr->rjb = 0;
	} else {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED_WITH_UNUSED;
	  ptr->found = DK4_FILE_ENCODING_UTF16_LE;
	}
      } break;
      case 4: {
        ptr->c2 = byte;
	ptr->rjb = 2;
        if (0x00 == byte) {
	  ptr->state = 5; back = DK4_EDSTM_ACCEPT;
	} else {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED_WITH_UNUSED;
	}
      } break;
      case 5: {
        ptr->c3 = byte;
	ptr->rjb = 3;
        if (0xFE == byte) {
	  ptr->state = 6; back = DK4_EDSTM_ACCEPT;
	} else {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED_WITH_UNUSED;
	}
      } break;
      case 6: {
        ptr->c4 = byte;
	ptr->rjb = 4;
        if (0xFF == byte) {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED;
	  ptr->found = DK4_FILE_ENCODING_32_BE;
	  ptr->rjb = 0;
	} else {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED_WITH_UNUSED;
	}
      } break;
      case 7: {
        ptr->c2 = byte;
	ptr->rjb = 2;
        if (0xFF == byte) {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED;
	  ptr->found = DK4_FILE_ENCODING_UTF16_BE;
	  ptr->rjb = 0;
	} else {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED_WITH_UNUSED;
	}
      } break;
      case 8: {
        ptr->c2 = byte;
	ptr->rjb = 2;
        if (0xBB == byte) {
	  ptr->state = 9; back = DK4_EDSTM_ACCEPT;
	} else {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED_WITH_UNUSED;
	}
      } break;
      case 9: {
        ptr->c3 = byte;
	ptr->rjb = 3;
        if (0xBF == byte) {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED;
	  ptr->found = DK4_FILE_ENCODING_UTF8;
	  ptr->rjb = 0;
	} else {
	  ptr->state = -1; back = DK4_EDSTM_FINISHED_WITH_UNUSED;
	}
      } break;
    }
  }
  return back;
}



int
dk4bom_detect_get_encoding(dk4_bom_detector_t *ptr)
{
  int	back	=	DK4_ENCODING_ASCII;
  if (NULL != ptr) {
    back = ptr->found;
  }
  return back;
}



size_t
dk4bom_detect_num_unused_bytes(dk4_bom_detector_t *ptr)
{
  size_t	back	=	0;
  if (NULL != ptr) {
    back = ptr->rjb;
  }
  return back;
}



unsigned char
dk4bom_detect_unused_byte(dk4_bom_detector_t *ptr, size_t num)
{
  unsigned char	back	=	0x00;
  if (NULL != ptr) {
    if (0 == num) {
      back = ptr->c1;
    } else {
      if (1 == num) {
        back = ptr->c2;
      } else {
        if (2 == num) {
	  back = ptr->c3;
	} else {
	  if (3 == num) {
	    back = ptr->c4;
	  }
	}
      }
    }
  }
  return back;
}



int
dk4bom_detect_in_detection(dk4_bom_detector_t *ptr)
{
  int		 back = 0;
  if (NULL != ptr) {
    if (-1 != ptr->state) {
      back = 1;
    }
  }
  return back;
}