summaryrefslogtreecommitdiff
path: root/Source/Core/Scanner.cs
blob: cfef86c75924ffd2bfb3edae87b3d46ecd1e8c6e (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
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771

using System;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics.Contracts;
using Microsoft.Boogie;


namespace Microsoft.Boogie {

//-----------------------------------------------------------------------------------
// Buffer
//-----------------------------------------------------------------------------------
public class Buffer {
	// This Buffer supports the following cases:
	// 1) seekable stream (file)
	//    a) whole stream in buffer
	//    b) part of stream in buffer
	// 2) non seekable stream (network, console)

	public const int EOF = 65535 + 1; // char.MaxValue + 1;
	const int MIN_BUFFER_LENGTH = 1024; // 1KB
	const int MAX_BUFFER_LENGTH = MIN_BUFFER_LENGTH * 64; // 64KB
	byte[]/*!*/ buf;         // input buffer
	int bufStart;       // position of first byte in buffer relative to input stream
	int bufLen;         // length of buffer
	int fileLen;        // length of input stream (may change if the stream is no file)
	int bufPos;         // current position in buffer
	Stream/*!*/ stream;      // input stream (seekable)
	bool isUserStream;  // was the stream opened by the user?

	[ContractInvariantMethod]
	void ObjectInvariant(){
		Contract.Invariant(buf != null);
		Contract.Invariant(stream != null);
	}

//  [NotDelayed]
	public Buffer (Stream/*!*/ s, bool isUserStream) : base() {
	  Contract.Requires(s != null);
		stream = s; this.isUserStream = isUserStream;

		int fl, bl;
		if (s.CanSeek) {
			fl = (int) s.Length;
			bl = fl < MAX_BUFFER_LENGTH ? fl : MAX_BUFFER_LENGTH; // Math.Min(fileLen, MAX_BUFFER_LENGTH);
			bufStart = Int32.MaxValue; // nothing in the buffer so far
		} else {
			fl = bl = bufStart = 0;
		}

		buf = new byte[(bl>0) ? bl : MIN_BUFFER_LENGTH];
		fileLen = fl;  bufLen = bl;

		if (fileLen > 0) Pos = 0; // setup buffer to position 0 (start)
		else bufPos = 0; // index 0 is already after the file, thus Pos = 0 is invalid
		if (bufLen == fileLen && s.CanSeek) Close();
	}

	protected Buffer(Buffer/*!*/ b) { // called in UTF8Buffer constructor
	  Contract.Requires(b != null);
		buf = b.buf;
		bufStart = b.bufStart;
		bufLen = b.bufLen;
		fileLen = b.fileLen;
		bufPos = b.bufPos;
		stream = b.stream;
		// keep destructor from closing the stream
		//b.stream = null;
		isUserStream = b.isUserStream;
		// keep destructor from closing the stream
		b.isUserStream = true;
	}

	~Buffer() { Close(); }

	protected void Close() {
		if (!isUserStream && stream != null) {
			stream.Close();
			//stream = null;
		}
	}

	public virtual int Read () {
		if (bufPos < bufLen) {
			return buf[bufPos++];
		} else if (Pos < fileLen) {
			Pos = Pos; // shift buffer start to Pos
			return buf[bufPos++];
		} else if (stream != null && !stream.CanSeek && ReadNextStreamChunk() > 0) {
			return buf[bufPos++];
		} else {
			return EOF;
		}
	}

	public int Peek () {
		int curPos = Pos;
		int ch = Read();
		Pos = curPos;
		return ch;
	}

	public string/*!*/ GetString (int beg, int end) {
	  Contract.Ensures(Contract.Result<string>() != null);
		int len = 0;
		char[] buf = new char[end - beg];
		int oldPos = Pos;
		Pos = beg;
		while (Pos < end) buf[len++] = (char) Read();
		Pos = oldPos;
		return new String(buf, 0, len);
	}

	public int Pos {
		get { return bufPos + bufStart; }
		set {
			if (value >= fileLen && stream != null && !stream.CanSeek) {
				// Wanted position is after buffer and the stream
				// is not seek-able e.g. network or console,
				// thus we have to read the stream manually till
				// the wanted position is in sight.
				while (value >= fileLen && ReadNextStreamChunk() > 0);
			}

			if (value < 0 || value > fileLen) {
				throw new FatalError("buffer out of bounds access, position: " + value);
			}

			if (value >= bufStart && value < bufStart + bufLen) { // already in buffer
				bufPos = value - bufStart;
			} else if (stream != null) { // must be swapped in
				stream.Seek(value, SeekOrigin.Begin);
				bufLen = stream.Read(buf, 0, buf.Length);
				bufStart = value; bufPos = 0;
			} else {
				// set the position to the end of the file, Pos will return fileLen.
				bufPos = fileLen - bufStart;
			}
		}
	}

	// Read the next chunk of bytes from the stream, increases the buffer
	// if needed and updates the fields fileLen and bufLen.
	// Returns the number of bytes read.
	private int ReadNextStreamChunk() {
		int free = buf.Length - bufLen;
		if (free == 0) {
			// in the case of a growing input stream
			// we can neither seek in the stream, nor can we
			// foresee the maximum length, thus we must adapt
			// the buffer size on demand.
			byte[] newBuf = new byte[bufLen * 2];
			Array.Copy(buf, newBuf, bufLen);
			buf = newBuf;
			free = bufLen;
		}
		int read = stream.Read(buf, bufLen, free);
		if (read > 0) {
			fileLen = bufLen = (bufLen + read);
			return read;
		}
		// end of stream reached
		return 0;
	}
}

//-----------------------------------------------------------------------------------
// UTF8Buffer
//-----------------------------------------------------------------------------------
public class UTF8Buffer: Buffer {
	public UTF8Buffer(Buffer/*!*/ b): base(b) {Contract.Requires(b != null);}

	public override int Read() {
		int ch;
		do {
			ch = base.Read();
			// until we find a utf8 start (0xxxxxxx or 11xxxxxx)
		} while ((ch >= 128) && ((ch & 0xC0) != 0xC0) && (ch != EOF));
		if (ch < 128 || ch == EOF) {
			// nothing to do, first 127 chars are the same in ascii and utf8
			// 0xxxxxxx or end of file character
		} else if ((ch & 0xF0) == 0xF0) {
			// 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
			int c1 = ch & 0x07; ch = base.Read();
			int c2 = ch & 0x3F; ch = base.Read();
			int c3 = ch & 0x3F; ch = base.Read();
			int c4 = ch & 0x3F;
			ch = (((((c1 << 6) | c2) << 6) | c3) << 6) | c4;
		} else if ((ch & 0xE0) == 0xE0) {
			// 1110xxxx 10xxxxxx 10xxxxxx
			int c1 = ch & 0x0F; ch = base.Read();
			int c2 = ch & 0x3F; ch = base.Read();
			int c3 = ch & 0x3F;
			ch = (((c1 << 6) | c2) << 6) | c3;
		} else if ((ch & 0xC0) == 0xC0) {
			// 110xxxxx 10xxxxxx
			int c1 = ch & 0x1F; ch = base.Read();
			int c2 = ch & 0x3F;
			ch = (c1 << 6) | c2;
		}
		return ch;
	}
}

//-----------------------------------------------------------------------------------
// Scanner
//-----------------------------------------------------------------------------------
public class Scanner {
	const char EOL = '\n';
	const int eofSym = 0; /* pdt */
	const int maxT = 88;
	const int noSym = 88;


	[ContractInvariantMethod]
	void objectInvariant(){
		Contract.Invariant(buffer!=null);
		Contract.Invariant(t != null);
		Contract.Invariant(start != null);
		Contract.Invariant(tokens != null);
		Contract.Invariant(pt != null);
		Contract.Invariant(tval != null);
		Contract.Invariant(Filename != null);
		Contract.Invariant(errorHandler != null);
	}

	public Buffer/*!*/ buffer; // scanner buffer

	Token/*!*/ t;          // current token
	int ch;           // current input character
	int pos;          // byte position of current character
	int charPos;
	int col;          // column number of current character
	int line;         // line number of current character
	int oldEols;      // EOLs that appeared in a comment;
	static readonly Hashtable/*!*/ start; // maps first token character to start state

	Token/*!*/ tokens;     // list of tokens already peeked (first token is a dummy)
	Token/*!*/ pt;         // current peek token

	char[]/*!*/ tval = new char[128]; // text of current token
	int tlen;         // length of current token

	private string/*!*/ Filename;
	private Errors/*!*/ errorHandler;

	static Scanner() {
		start = new Hashtable(128);
		for (int i = 35; i <= 36; ++i) start[i] = 2;
		for (int i = 39; i <= 39; ++i) start[i] = 2;
		for (int i = 46; i <= 46; ++i) start[i] = 2;
		for (int i = 63; i <= 63; ++i) start[i] = 2;
		for (int i = 65; i <= 90; ++i) start[i] = 2;
		for (int i = 94; i <= 122; ++i) start[i] = 2;
		for (int i = 126; i <= 126; ++i) start[i] = 2;
		for (int i = 48; i <= 57; ++i) start[i] = 9;
		for (int i = 34; i <= 34; ++i) start[i] = 6;
		start[92] = 1; 
		start[59] = 12; 
		start[40] = 13; 
		start[41] = 14; 
		start[58] = 49; 
		start[44] = 15; 
		start[91] = 16; 
		start[93] = 17; 
		start[60] = 50; 
		start[62] = 51; 
		start[123] = 18; 
		start[125] = 52; 
		start[61] = 53; 
		start[42] = 19; 
		start[8660] = 22; 
		start[8658] = 24; 
		start[8656] = 25; 
		start[38] = 26; 
		start[8743] = 28; 
		start[124] = 54; 
		start[8744] = 30; 
		start[33] = 55; 
		start[8800] = 34; 
		start[8804] = 35; 
		start[8805] = 36; 
		start[43] = 56; 
		start[45] = 38; 
		start[47] = 39; 
		start[37] = 40; 
		start[172] = 41; 
		start[8704] = 44; 
		start[8707] = 45; 
		start[955] = 46; 
		start[8226] = 48; 
		start[Buffer.EOF] = -1;

	}

//	[NotDelayed]
	public Scanner (string/*!*/ fileName, Errors/*!*/ errorHandler) : base() {
	  Contract.Requires(fileName != null);
	  Contract.Requires(errorHandler != null);
		this.errorHandler = errorHandler;
		pt = tokens = new Token();  // first token is a dummy
		t = new Token(); // dummy because t is a non-null field
		try {
			Stream stream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);
			buffer = new Buffer(stream, false);
			Filename = fileName;
			Init();
		} catch (IOException) {
			throw new FatalError("Cannot open file " + fileName);
		}
	}

//	[NotDelayed]
	public Scanner (Stream/*!*/ s, Errors/*!*/ errorHandler, string/*!*/ fileName) : base() {
	  Contract.Requires(s != null);
	  Contract.Requires(errorHandler != null);
	  Contract.Requires(fileName != null);
		pt = tokens = new Token();  // first token is a dummy
		t = new Token(); // dummy because t is a non-null field
		buffer = new Buffer(s, true);
		this.errorHandler = errorHandler;
		this.Filename = fileName;
		Init();
	}

	void Init() {
		pos = -1; line = 1; col = 0;
		oldEols = 0;
		NextCh();
		if (ch == 0xEF) { // check optional byte order mark for UTF-8
			NextCh(); int ch1 = ch;
			NextCh(); int ch2 = ch;
			if (ch1 != 0xBB || ch2 != 0xBF) {
				throw new FatalError(String.Format("illegal byte order mark: EF {0,2:X} {1,2:X}", ch1, ch2));
			}
			buffer = new UTF8Buffer(buffer); col = 0;
			NextCh();
		}
		pt = tokens = new Token();  // first token is a dummy
	}

	string/*!*/ ReadToEOL(){
	Contract.Ensures(Contract.Result<string>() != null);
	  int p = buffer.Pos;
	  int ch = buffer.Read();
	  // replace isolated '\r' by '\n' in order to make
	  // eol handling uniform across Windows, Unix and Mac
	  if (ch == '\r' && buffer.Peek() != '\n') ch = EOL;
	  while (ch != EOL && ch != Buffer.EOF){
		ch = buffer.Read();
		// replace isolated '\r' by '\n' in order to make
		// eol handling uniform across Windows, Unix and Mac
		if (ch == '\r' && buffer.Peek() != '\n') ch = EOL;
	  }
	  string/*!*/ s = buffer.GetString(p, buffer.Pos);
	  Contract.Assert(s!=null);
	  return s;
	}

	void NextCh() {
		if (oldEols > 0) { ch = EOL; oldEols--; }
		else {
//			pos = buffer.Pos;
//			ch = buffer.Read(); col++;
//			// replace isolated '\r' by '\n' in order to make
//			// eol handling uniform across Windows, Unix and Mac
//			if (ch == '\r' && buffer.Peek() != '\n') ch = EOL;
//			if (ch == EOL) { line++; col = 0; }

			while (true) {
				pos = buffer.Pos;
				ch = buffer.Read(); col++;
				// replace isolated '\r' by '\n' in order to make
				// eol handling uniform across Windows, Unix and Mac
				if (ch == '\r' && buffer.Peek() != '\n') ch = EOL;
				if (ch == EOL) {
					line++; col = 0;
				} else if (ch == '#' && col == 1) {
				  int prLine = line;
				  int prColumn = 0;

				  string/*!*/ hashLine = ReadToEOL();
				  Contract.Assert(hashLine!=null);
				  col = 0;
				  line++;

				  hashLine = hashLine.TrimEnd(null);
				  if (hashLine.StartsWith("line ") || hashLine == "line") {
					// parse #line pragma:  #line num [filename]
					string h = hashLine.Substring(4).TrimStart(null);
					int x = h.IndexOf(' ');
					if (x == -1) {
					  x = h.Length;  // this will be convenient below when we look for a filename
					}
					try {
					  int li = int.Parse(h.Substring(0, x));

					  h = h.Substring(x).Trim();

					  // act on #line
					  line = li;
					  if (h.Length != 0) {
						// a filename was specified
						Filename = h;
					  }
					  continue;  // successfully parsed and acted on the #line pragma

					} catch (FormatException) {
					  // just fall down through to produce an error message
					}
					this.errorHandler.SemErr(Filename, prLine, prColumn, "Malformed (#line num [filename]) pragma: #" + hashLine);
					continue;
				  }

				  this.errorHandler.SemErr(Filename, prLine, prColumn, "Unrecognized pragma: #" + hashLine);
				  continue;
				}
				return;
			  }


		}

	}

	void AddCh() {
		if (tlen >= tval.Length) {
			char[] newBuf = new char[2 * tval.Length];
			Array.Copy(tval, 0, newBuf, 0, tval.Length);
			tval = newBuf;
		}
		if (ch != Buffer.EOF) {
			tval[tlen++] = (char) ch;
			NextCh();
		}
	}



	bool Comment0() {
		int level = 1, pos0 = pos, line0 = line, col0 = col, charPos0 = charPos;
		NextCh();
		if (ch == '/') {
			NextCh();
			for(;;) {
				if (ch == 10) {
					level--;
					if (level == 0) { oldEols = line - line0; NextCh(); return true; }
					NextCh();
				} else if (ch == Buffer.EOF) return false;
				else NextCh();
			}
		} else {
			buffer.Pos = pos0; NextCh(); line = line0; col = col0; charPos = charPos0;
		}
		return false;
	}

	bool Comment1() {
		int level = 1, pos0 = pos, line0 = line, col0 = col, charPos0 = charPos;
		NextCh();
		if (ch == '*') {
			NextCh();
			for(;;) {
				if (ch == '*') {
					NextCh();
					if (ch == '/') {
						level--;
						if (level == 0) { oldEols = line - line0; NextCh(); return true; }
						NextCh();
					}
				} else if (ch == '/') {
					NextCh();
					if (ch == '*') {
						level++; NextCh();
					}
				} else if (ch == Buffer.EOF) return false;
				else NextCh();
			}
		} else {
			buffer.Pos = pos0; NextCh(); line = line0; col = col0; charPos = charPos0;
		}
		return false;
	}


	void CheckLiteral() {
		switch (t.val) {
			case "var": t.kind = 6; break;
			case "where": t.kind = 12; break;
			case "int": t.kind = 13; break;
			case "bool": t.kind = 14; break;
			case "const": t.kind = 19; break;
			case "unique": t.kind = 20; break;
			case "extends": t.kind = 21; break;
			case "complete": t.kind = 22; break;
			case "function": t.kind = 23; break;
			case "returns": t.kind = 24; break;
			case "axiom": t.kind = 27; break;
			case "type": t.kind = 28; break;
			case "procedure": t.kind = 30; break;
			case "implementation": t.kind = 31; break;
			case "modifies": t.kind = 32; break;
			case "free": t.kind = 33; break;
			case "requires": t.kind = 34; break;
			case "ensures": t.kind = 35; break;
			case "goto": t.kind = 36; break;
			case "return": t.kind = 37; break;
			case "if": t.kind = 38; break;
			case "else": t.kind = 39; break;
			case "while": t.kind = 40; break;
			case "invariant": t.kind = 41; break;
			case "break": t.kind = 43; break;
			case "assert": t.kind = 44; break;
			case "assume": t.kind = 45; break;
			case "havoc": t.kind = 46; break;
			case "call": t.kind = 48; break;
			case "forall": t.kind = 49; break;
			case "false": t.kind = 75; break;
			case "true": t.kind = 76; break;
			case "old": t.kind = 77; break;
			case "then": t.kind = 80; break;
			case "exists": t.kind = 82; break;
			case "lambda": t.kind = 84; break;
			default: break;
		}
	}

	Token/*!*/ NextToken() {
	  Contract.Ensures(Contract.Result<Token>() != null);
		while (ch == ' ' ||
			ch >= 9 && ch <= 10 || ch == 13
		) NextCh();
		if (ch == '/' && Comment0() ||ch == '/' && Comment1()) return NextToken();
		int recKind = noSym;
		int recEnd = pos;
		t = new Token();
		t.pos = pos; t.col = col; t.line = line;
		t.filename = this.Filename;
		int state;
		if (start.ContainsKey(ch)) {
			Contract.Assert(start[ch] != null);
			state = (int) start[ch];
		}
		else { state = 0; }
		tlen = 0; AddCh();

		switch (state) {
			case -1: { t.kind = eofSym; break; } // NextCh already done
			case 0: {
				if (recKind != noSym) {
					tlen = recEnd - t.pos;
					SetScannerBehindT();
				}
				t.kind = recKind; break;
			} // NextCh already done
			case 1:
				if (ch >= '#' && ch <= '$' || ch == 39 || ch == '.' || ch == '?' || ch >= 'A' && ch <= 'Z' || ch >= '^' && ch <= 'z' || ch == '~') {AddCh(); goto case 2;}
				else {goto case 0;}
			case 2:
				recEnd = pos; recKind = 1;
				if (ch >= '#' && ch <= '$' || ch == 39 || ch == '.' || ch >= '0' && ch <= '9' || ch == '?' || ch >= 'A' && ch <= 'Z' || ch >= '^' && ch <= 'z' || ch == '~') {AddCh(); goto case 2;}
				else {t.kind = 1; t.val = new String(tval, 0, tlen); CheckLiteral(); return t;}
			case 3:
				if (ch == 'v') {AddCh(); goto case 4;}
				else {goto case 0;}
			case 4:
				if (ch >= '0' && ch <= '9') {AddCh(); goto case 5;}
				else {goto case 0;}
			case 5:
				recEnd = pos; recKind = 2;
				if (ch >= '0' && ch <= '9') {AddCh(); goto case 5;}
				else {t.kind = 2; break;}
			case 6:
				if (ch == '"') {AddCh(); goto case 7;}
				else if (ch <= 9 || ch >= 11 && ch <= 12 || ch >= 14 && ch <= '!' || ch >= '#' && ch <= '[' || ch >= ']' && ch <= 65535) {AddCh(); goto case 6;}
				else if (ch == 92) {AddCh(); goto case 10;}
				else {goto case 0;}
			case 7:
				{t.kind = 4; break;}
			case 8:
				recEnd = pos; recKind = 5;
				if (ch >= '0' && ch <= '9') {AddCh(); goto case 8;}
				else {t.kind = 5; break;}
			case 9:
				recEnd = pos; recKind = 3;
				if (ch >= '0' && ch <= '9') {AddCh(); goto case 9;}
				else if (ch == 'b') {AddCh(); goto case 3;}
				else if (ch == '.') {AddCh(); goto case 8;}
				else {t.kind = 3; break;}
			case 10:
				if (ch == '"') {AddCh(); goto case 11;}
				else if (ch <= 9 || ch >= 11 && ch <= 12 || ch >= 14 && ch <= '!' || ch >= '#' && ch <= '[' || ch >= ']' && ch <= 65535) {AddCh(); goto case 6;}
				else if (ch == 92) {AddCh(); goto case 10;}
				else {goto case 0;}
			case 11:
				recEnd = pos; recKind = 4;
				if (ch == '"') {AddCh(); goto case 7;}
				else if (ch <= 9 || ch >= 11 && ch <= 12 || ch >= 14 && ch <= '!' || ch >= '#' && ch <= '[' || ch >= ']' && ch <= 65535) {AddCh(); goto case 6;}
				else if (ch == 92) {AddCh(); goto case 10;}
				else {t.kind = 4; break;}
			case 12:
				{t.kind = 7; break;}
			case 13:
				{t.kind = 8; break;}
			case 14:
				{t.kind = 9; break;}
			case 15:
				{t.kind = 11; break;}
			case 16:
				{t.kind = 15; break;}
			case 17:
				{t.kind = 16; break;}
			case 18:
				{t.kind = 25; break;}
			case 19:
				{t.kind = 42; break;}
			case 20:
				{t.kind = 47; break;}
			case 21:
				{t.kind = 50; break;}
			case 22:
				{t.kind = 51; break;}
			case 23:
				{t.kind = 52; break;}
			case 24:
				{t.kind = 53; break;}
			case 25:
				{t.kind = 55; break;}
			case 26:
				if (ch == '&') {AddCh(); goto case 27;}
				else {goto case 0;}
			case 27:
				{t.kind = 56; break;}
			case 28:
				{t.kind = 57; break;}
			case 29:
				{t.kind = 58; break;}
			case 30:
				{t.kind = 59; break;}
			case 31:
				{t.kind = 62; break;}
			case 32:
				{t.kind = 63; break;}
			case 33:
				{t.kind = 64; break;}
			case 34:
				{t.kind = 65; break;}
			case 35:
				{t.kind = 66; break;}
			case 36:
				{t.kind = 67; break;}
			case 37:
				{t.kind = 68; break;}
			case 38:
				{t.kind = 70; break;}
			case 39:
				{t.kind = 71; break;}
			case 40:
				{t.kind = 72; break;}
			case 41:
				{t.kind = 74; break;}
			case 42:
				{t.kind = 78; break;}
			case 43:
				{t.kind = 79; break;}
			case 44:
				{t.kind = 81; break;}
			case 45:
				{t.kind = 83; break;}
			case 46:
				{t.kind = 85; break;}
			case 47:
				{t.kind = 86; break;}
			case 48:
				{t.kind = 87; break;}
			case 49:
				recEnd = pos; recKind = 10;
				if (ch == '=') {AddCh(); goto case 20;}
				else if (ch == ':') {AddCh(); goto case 47;}
				else {t.kind = 10; break;}
			case 50:
				recEnd = pos; recKind = 17;
				if (ch == '=') {AddCh(); goto case 57;}
				else if (ch == ':') {AddCh(); goto case 33;}
				else {t.kind = 17; break;}
			case 51:
				recEnd = pos; recKind = 18;
				if (ch == '=') {AddCh(); goto case 31;}
				else {t.kind = 18; break;}
			case 52:
				recEnd = pos; recKind = 26;
				if (ch == '|') {AddCh(); goto case 43;}
				else {t.kind = 26; break;}
			case 53:
				recEnd = pos; recKind = 29;
				if (ch == '=') {AddCh(); goto case 58;}
				else {t.kind = 29; break;}
			case 54:
				if (ch == '|') {AddCh(); goto case 29;}
				else if (ch == '{') {AddCh(); goto case 42;}
				else {goto case 0;}
			case 55:
				recEnd = pos; recKind = 73;
				if (ch == '=') {AddCh(); goto case 32;}
				else {t.kind = 73; break;}
			case 56:
				recEnd = pos; recKind = 69;
				if (ch == '+') {AddCh(); goto case 37;}
				else {t.kind = 69; break;}
			case 57:
				recEnd = pos; recKind = 61;
				if (ch == '=') {AddCh(); goto case 59;}
				else {t.kind = 61; break;}
			case 58:
				recEnd = pos; recKind = 60;
				if (ch == '>') {AddCh(); goto case 23;}
				else {t.kind = 60; break;}
			case 59:
				recEnd = pos; recKind = 54;
				if (ch == '>') {AddCh(); goto case 21;}
				else {t.kind = 54; break;}

		}
		t.val = new String(tval, 0, tlen);
		return t;
	}

	private void SetScannerBehindT() {
		buffer.Pos = t.pos;
		NextCh();
		line = t.line; col = t.col;
		for (int i = 0; i < tlen; i++) NextCh();
	}

	// get the next token (possibly a token already seen during peeking)
	public Token/*!*/ Scan () {
	 Contract.Ensures(Contract.Result<Token>() != null);
		if (tokens.next == null) {
			return NextToken();
		} else {
			pt = tokens = tokens.next;
			return tokens;
		}
	}

	// peek for the next token, ignore pragmas
	public Token/*!*/ Peek () {
	  Contract.Ensures(Contract.Result<Token>() != null);
		do {
			if (pt.next == null) {
				pt.next = NextToken();
			}
			pt = pt.next;
		} while (pt.kind > maxT); // skip pragmas

		return pt;
	}

	// make sure that peeking starts at the current scan position
	public void ResetPeek () { pt = tokens; }

} // end Scanner

public delegate void ErrorProc(int n, string filename, int line, int col);


}