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[official-gcc.git] / gcc / ada / s-regpat.adb
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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT LIBRARY COMPONENTS --
4 -- --
5 -- G N A T . R E G P A T --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1986 by University of Toronto. --
10 -- Copyright (C) 1999-2013, AdaCore --
11 -- --
12 -- GNAT is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 3, or (at your option) any later ver- --
15 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. --
18 -- --
19 -- As a special exception under Section 7 of GPL version 3, you are granted --
20 -- additional permissions described in the GCC Runtime Library Exception, --
21 -- version 3.1, as published by the Free Software Foundation. --
22 -- --
23 -- You should have received a copy of the GNU General Public License and --
24 -- a copy of the GCC Runtime Library Exception along with this program; --
25 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
26 -- <http://www.gnu.org/licenses/>. --
27 -- --
28 -- GNAT was originally developed by the GNAT team at New York University. --
29 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 -- --
31 ------------------------------------------------------------------------------
32
33 -- This is an altered Ada 95 version of the original V8 style regular
34 -- expression library written in C by Henry Spencer. Apart from the
35 -- translation to Ada, the interface has been considerably changed to
36 -- use the Ada String type instead of C-style nul-terminated strings.
37
38 -- Beware that some of this code is subtly aware of the way operator
39 -- precedence is structured in regular expressions. Serious changes in
40 -- regular-expression syntax might require a total rethink.
41
42 with System.IO; use System.IO;
43 with Ada.Characters.Handling; use Ada.Characters.Handling;
44 with Ada.Unchecked_Conversion;
45
46 package body System.Regpat is
47
48 Debug : constant Boolean := False;
49 -- Set to True to activate debug traces. This is normally set to constant
50 -- False to simply delete all the trace code. It is to be edited to True
51 -- for internal debugging of the package.
52
53 ----------------------------
54 -- Implementation details --
55 ----------------------------
56
57 -- This is essentially a linear encoding of a nondeterministic
58 -- finite-state machine, also known as syntax charts or
59 -- "railroad normal form" in parsing technology.
60
61 -- Each node is an opcode plus a "next" pointer, possibly plus an
62 -- operand. "Next" pointers of all nodes except BRANCH implement
63 -- concatenation; a "next" pointer with a BRANCH on both ends of it
64 -- is connecting two alternatives.
65
66 -- The operand of some types of node is a literal string; for others,
67 -- it is a node leading into a sub-FSM. In particular, the operand of
68 -- a BRANCH node is the first node of the branch.
69 -- (NB this is *not* a tree structure: the tail of the branch connects
70 -- to the thing following the set of BRANCHes).
71
72 -- You can see the exact byte-compiled version by using the Dump
73 -- subprogram. However, here are a few examples:
74
75 -- (a|b): 1 : BRANCH (next at 9)
76 -- 4 : EXACT (next at 17) operand=a
77 -- 9 : BRANCH (next at 17)
78 -- 12 : EXACT (next at 17) operand=b
79 -- 17 : EOP (next at 0)
80 --
81 -- (ab)*: 1 : CURLYX (next at 25) { 0, 32767}
82 -- 8 : OPEN 1 (next at 12)
83 -- 12 : EXACT (next at 18) operand=ab
84 -- 18 : CLOSE 1 (next at 22)
85 -- 22 : WHILEM (next at 0)
86 -- 25 : NOTHING (next at 28)
87 -- 28 : EOP (next at 0)
88
89 -- The opcodes are:
90
91 type Opcode is
92
93 -- Name Operand? Meaning
94
95 (EOP, -- no End of program
96 MINMOD, -- no Next operator is not greedy
97
98 -- Classes of characters
99
100 ANY, -- no Match any one character except newline
101 SANY, -- no Match any character, including new line
102 ANYOF, -- class Match any character in this class
103 EXACT, -- str Match this string exactly
104 EXACTF, -- str Match this string (case-folding is one)
105 NOTHING, -- no Match empty string
106 SPACE, -- no Match any whitespace character
107 NSPACE, -- no Match any non-whitespace character
108 DIGIT, -- no Match any numeric character
109 NDIGIT, -- no Match any non-numeric character
110 ALNUM, -- no Match any alphanumeric character
111 NALNUM, -- no Match any non-alphanumeric character
112
113 -- Branches
114
115 BRANCH, -- node Match this alternative, or the next
116
117 -- Simple loops (when the following node is one character in length)
118
119 STAR, -- node Match this simple thing 0 or more times
120 PLUS, -- node Match this simple thing 1 or more times
121 CURLY, -- 2num node Match this simple thing between n and m times.
122
123 -- Complex loops
124
125 CURLYX, -- 2num node Match this complex thing {n,m} times
126 -- The nums are coded on two characters each
127
128 WHILEM, -- no Do curly processing and see if rest matches
129
130 -- Matches after or before a word
131
132 BOL, -- no Match "" at beginning of line
133 MBOL, -- no Same, assuming multiline (match after \n)
134 SBOL, -- no Same, assuming single line (don't match at \n)
135 EOL, -- no Match "" at end of line
136 MEOL, -- no Same, assuming multiline (match before \n)
137 SEOL, -- no Same, assuming single line (don't match at \n)
138
139 BOUND, -- no Match "" at any word boundary
140 NBOUND, -- no Match "" at any word non-boundary
141
142 -- Parenthesis groups handling
143
144 REFF, -- num Match some already matched string, folded
145 OPEN, -- num Mark this point in input as start of #n
146 CLOSE); -- num Analogous to OPEN
147
148 for Opcode'Size use 8;
149
150 -- Opcode notes:
151
152 -- BRANCH
153 -- The set of branches constituting a single choice are hooked
154 -- together with their "next" pointers, since precedence prevents
155 -- anything being concatenated to any individual branch. The
156 -- "next" pointer of the last BRANCH in a choice points to the
157 -- thing following the whole choice. This is also where the
158 -- final "next" pointer of each individual branch points; each
159 -- branch starts with the operand node of a BRANCH node.
160
161 -- STAR,PLUS
162 -- '?', and complex '*' and '+', are implemented with CURLYX.
163 -- branches. Simple cases (one character per match) are implemented with
164 -- STAR and PLUS for speed and to minimize recursive plunges.
165
166 -- OPEN,CLOSE
167 -- ...are numbered at compile time.
168
169 -- EXACT, EXACTF
170 -- There are in fact two arguments, the first one is the length (minus
171 -- one of the string argument), coded on one character, the second
172 -- argument is the string itself, coded on length + 1 characters.
173
174 -- A node is one char of opcode followed by two chars of "next" pointer.
175 -- "Next" pointers are stored as two 8-bit pieces, high order first. The
176 -- value is a positive offset from the opcode of the node containing it.
177 -- An operand, if any, simply follows the node. (Note that much of the
178 -- code generation knows about this implicit relationship.)
179
180 -- Using two bytes for the "next" pointer is vast overkill for most
181 -- things, but allows patterns to get big without disasters.
182
183 Next_Pointer_Bytes : constant := 3;
184 -- Points after the "next pointer" data. An instruction is therefore:
185 -- 1 byte: instruction opcode
186 -- 2 bytes: pointer to next instruction
187 -- * bytes: optional data for the instruction
188
189 -----------------------
190 -- Character classes --
191 -----------------------
192 -- This is the implementation for character classes ([...]) in the
193 -- syntax for regular expressions. Each character (0..256) has an
194 -- entry into the table. This makes for a very fast matching
195 -- algorithm.
196
197 type Class_Byte is mod 256;
198 type Character_Class is array (Class_Byte range 0 .. 31) of Class_Byte;
199
200 type Bit_Conversion_Array is array (Class_Byte range 0 .. 7) of Class_Byte;
201 Bit_Conversion : constant Bit_Conversion_Array :=
202 (1, 2, 4, 8, 16, 32, 64, 128);
203
204 type Std_Class is (ANYOF_NONE,
205 ANYOF_ALNUM, -- Alphanumeric class [a-zA-Z0-9]
206 ANYOF_NALNUM,
207 ANYOF_SPACE, -- Space class [ \t\n\r\f]
208 ANYOF_NSPACE,
209 ANYOF_DIGIT, -- Digit class [0-9]
210 ANYOF_NDIGIT,
211 ANYOF_ALNUMC, -- Alphanumeric class [a-zA-Z0-9]
212 ANYOF_NALNUMC,
213 ANYOF_ALPHA, -- Alpha class [a-zA-Z]
214 ANYOF_NALPHA,
215 ANYOF_ASCII, -- Ascii class (7 bits) 0..127
216 ANYOF_NASCII,
217 ANYOF_CNTRL, -- Control class
218 ANYOF_NCNTRL,
219 ANYOF_GRAPH, -- Graphic class
220 ANYOF_NGRAPH,
221 ANYOF_LOWER, -- Lower case class [a-z]
222 ANYOF_NLOWER,
223 ANYOF_PRINT, -- printable class
224 ANYOF_NPRINT,
225 ANYOF_PUNCT, --
226 ANYOF_NPUNCT,
227 ANYOF_UPPER, -- Upper case class [A-Z]
228 ANYOF_NUPPER,
229 ANYOF_XDIGIT, -- Hexadecimal digit
230 ANYOF_NXDIGIT
231 );
232
233 procedure Set_In_Class
234 (Bitmap : in out Character_Class;
235 C : Character);
236 -- Set the entry to True for C in the class Bitmap
237
238 function Get_From_Class
239 (Bitmap : Character_Class;
240 C : Character) return Boolean;
241 -- Return True if the entry is set for C in the class Bitmap
242
243 procedure Reset_Class (Bitmap : out Character_Class);
244 -- Clear all the entries in the class Bitmap
245
246 pragma Inline (Set_In_Class);
247 pragma Inline (Get_From_Class);
248 pragma Inline (Reset_Class);
249
250 -----------------------
251 -- Local Subprograms --
252 -----------------------
253
254 function "=" (Left : Character; Right : Opcode) return Boolean;
255
256 function Is_Alnum (C : Character) return Boolean;
257 -- Return True if C is an alphanum character or an underscore ('_')
258
259 function Is_White_Space (C : Character) return Boolean;
260 -- Return True if C is a whitespace character
261
262 function Is_Printable (C : Character) return Boolean;
263 -- Return True if C is a printable character
264
265 function Operand (P : Pointer) return Pointer;
266 -- Return a pointer to the first operand of the node at P
267
268 function String_Length
269 (Program : Program_Data;
270 P : Pointer) return Program_Size;
271 -- Return the length of the string argument of the node at P
272
273 function String_Operand (P : Pointer) return Pointer;
274 -- Return a pointer to the string argument of the node at P
275
276 procedure Bitmap_Operand
277 (Program : Program_Data;
278 P : Pointer;
279 Op : out Character_Class);
280 -- Return a pointer to the string argument of the node at P
281
282 function Get_Next
283 (Program : Program_Data;
284 IP : Pointer) return Pointer;
285 -- Dig the next instruction pointer out of a node
286
287 procedure Optimize (Self : in out Pattern_Matcher);
288 -- Optimize a Pattern_Matcher by noting certain special cases
289
290 function Read_Natural
291 (Program : Program_Data;
292 IP : Pointer) return Natural;
293 -- Return the 2-byte natural coded at position IP
294
295 -- All of the subprograms above are tiny and should be inlined
296
297 pragma Inline ("=");
298 pragma Inline (Is_Alnum);
299 pragma Inline (Is_White_Space);
300 pragma Inline (Get_Next);
301 pragma Inline (Operand);
302 pragma Inline (Read_Natural);
303 pragma Inline (String_Length);
304 pragma Inline (String_Operand);
305
306 type Expression_Flags is record
307 Has_Width, -- Known never to match null string
308 Simple, -- Simple enough to be STAR/PLUS operand
309 SP_Start : Boolean; -- Starts with * or +
310 end record;
311
312 Worst_Expression : constant Expression_Flags := (others => False);
313 -- Worst case
314
315 procedure Dump_Until
316 (Program : Program_Data;
317 Index : in out Pointer;
318 Till : Pointer;
319 Indent : Natural;
320 Do_Print : Boolean := True);
321 -- Dump the program until the node Till (not included) is met. Every line
322 -- is indented with Index spaces at the beginning Dumps till the end if
323 -- Till is 0.
324
325 procedure Dump_Operation
326 (Program : Program_Data;
327 Index : Pointer;
328 Indent : Natural);
329 -- Same as above, but only dumps a single operation, and compute its
330 -- indentation from the program.
331
332 ---------
333 -- "=" --
334 ---------
335
336 function "=" (Left : Character; Right : Opcode) return Boolean is
337 begin
338 return Character'Pos (Left) = Opcode'Pos (Right);
339 end "=";
340
341 --------------------
342 -- Bitmap_Operand --
343 --------------------
344
345 procedure Bitmap_Operand
346 (Program : Program_Data;
347 P : Pointer;
348 Op : out Character_Class)
349 is
350 function Convert is new Ada.Unchecked_Conversion
351 (Program_Data, Character_Class);
352
353 begin
354 Op (0 .. 31) := Convert (Program (P + Next_Pointer_Bytes .. P + 34));
355 end Bitmap_Operand;
356
357 -------------
358 -- Compile --
359 -------------
360
361 procedure Compile
362 (Matcher : out Pattern_Matcher;
363 Expression : String;
364 Final_Code_Size : out Program_Size;
365 Flags : Regexp_Flags := No_Flags)
366 is
367 -- We can't allocate space until we know how big the compiled form
368 -- will be, but we can't compile it (and thus know how big it is)
369 -- until we've got a place to put the code. So we cheat: we compile
370 -- it twice, once with code generation turned off and size counting
371 -- turned on, and once "for real".
372
373 -- This also means that we don't allocate space until we are sure
374 -- that the thing really will compile successfully, and we never
375 -- have to move the code and thus invalidate pointers into it.
376
377 -- Beware that the optimization-preparation code in here knows
378 -- about some of the structure of the compiled regexp.
379
380 PM : Pattern_Matcher renames Matcher;
381 Program : Program_Data renames PM.Program;
382
383 Emit_Ptr : Pointer := Program_First;
384
385 Parse_Pos : Natural := Expression'First; -- Input-scan pointer
386 Parse_End : constant Natural := Expression'Last;
387
388 ----------------------------
389 -- Subprograms for Create --
390 ----------------------------
391
392 procedure Emit (B : Character);
393 -- Output the Character B to the Program. If code-generation is
394 -- disabled, simply increments the program counter.
395
396 function Emit_Node (Op : Opcode) return Pointer;
397 -- If code-generation is enabled, Emit_Node outputs the
398 -- opcode Op and reserves space for a pointer to the next node.
399 -- Return value is the location of new opcode, i.e. old Emit_Ptr.
400
401 procedure Emit_Natural (IP : Pointer; N : Natural);
402 -- Split N on two characters at position IP
403
404 procedure Emit_Class (Bitmap : Character_Class);
405 -- Emits a character class
406
407 procedure Case_Emit (C : Character);
408 -- Emit C, after converting is to lower-case if the regular
409 -- expression is case insensitive.
410
411 procedure Parse
412 (Parenthesized : Boolean;
413 Flags : out Expression_Flags;
414 IP : out Pointer);
415 -- Parse regular expression, i.e. main body or parenthesized thing
416 -- Caller must absorb opening parenthesis.
417
418 procedure Parse_Branch
419 (Flags : out Expression_Flags;
420 First : Boolean;
421 IP : out Pointer);
422 -- Implements the concatenation operator and handles '|'
423 -- First should be true if this is the first item of the alternative.
424
425 procedure Parse_Piece
426 (Expr_Flags : out Expression_Flags;
427 IP : out Pointer);
428 -- Parse something followed by possible [*+?]
429
430 procedure Parse_Atom
431 (Expr_Flags : out Expression_Flags;
432 IP : out Pointer);
433 -- Parse_Atom is the lowest level parse procedure.
434 --
435 -- Optimization: Gobbles an entire sequence of ordinary characters so
436 -- that it can turn them into a single node, which is smaller to store
437 -- and faster to run. Backslashed characters are exceptions, each
438 -- becoming a separate node; the code is simpler that way and it's
439 -- not worth fixing.
440
441 procedure Insert_Operator
442 (Op : Opcode;
443 Operand : Pointer;
444 Greedy : Boolean := True);
445 -- Insert_Operator inserts an operator in front of an already-emitted
446 -- operand and relocates the operand. This applies to PLUS and STAR.
447 -- If Minmod is True, then the operator is non-greedy.
448
449 function Insert_Operator_Before
450 (Op : Opcode;
451 Operand : Pointer;
452 Greedy : Boolean;
453 Opsize : Pointer) return Pointer;
454 -- Insert an operator before Operand (and move the latter forward in the
455 -- program). Opsize is the size needed to represent the operator. This
456 -- returns the position at which the operator was inserted, and moves
457 -- Emit_Ptr after the new position of the operand.
458
459 procedure Insert_Curly_Operator
460 (Op : Opcode;
461 Min : Natural;
462 Max : Natural;
463 Operand : Pointer;
464 Greedy : Boolean := True);
465 -- Insert an operator for CURLY ({Min}, {Min,} or {Min,Max}).
466 -- If Minmod is True, then the operator is non-greedy.
467
468 procedure Link_Tail (P, Val : Pointer);
469 -- Link_Tail sets the next-pointer at the end of a node chain
470
471 procedure Link_Operand_Tail (P, Val : Pointer);
472 -- Link_Tail on operand of first argument; noop if operand-less
473
474 procedure Fail (M : String);
475 pragma No_Return (Fail);
476 -- Fail with a diagnostic message, if possible
477
478 function Is_Curly_Operator (IP : Natural) return Boolean;
479 -- Return True if IP is looking at a '{' that is the beginning
480 -- of a curly operator, i.e. it matches {\d+,?\d*}
481
482 function Is_Mult (IP : Natural) return Boolean;
483 -- Return True if C is a regexp multiplier: '+', '*' or '?'
484
485 procedure Get_Curly_Arguments
486 (IP : Natural;
487 Min : out Natural;
488 Max : out Natural;
489 Greedy : out Boolean);
490 -- Parse the argument list for a curly operator.
491 -- It is assumed that IP is indeed pointing at a valid operator.
492 -- So what is IP and how come IP is not referenced in the body ???
493
494 procedure Parse_Character_Class (IP : out Pointer);
495 -- Parse a character class.
496 -- The calling subprogram should consume the opening '[' before.
497
498 procedure Parse_Literal
499 (Expr_Flags : out Expression_Flags;
500 IP : out Pointer);
501 -- Parse_Literal encodes a string of characters to be matched exactly
502
503 function Parse_Posix_Character_Class return Std_Class;
504 -- Parse a posix character class, like [:alpha:] or [:^alpha:].
505 -- The caller is supposed to absorb the opening [.
506
507 pragma Inline (Is_Mult);
508 pragma Inline (Emit_Natural);
509 pragma Inline (Parse_Character_Class); -- since used only once
510
511 ---------------
512 -- Case_Emit --
513 ---------------
514
515 procedure Case_Emit (C : Character) is
516 begin
517 if (Flags and Case_Insensitive) /= 0 then
518 Emit (To_Lower (C));
519
520 else
521 -- Dump current character
522
523 Emit (C);
524 end if;
525 end Case_Emit;
526
527 ----------
528 -- Emit --
529 ----------
530
531 procedure Emit (B : Character) is
532 begin
533 if Emit_Ptr <= PM.Size then
534 Program (Emit_Ptr) := B;
535 end if;
536
537 Emit_Ptr := Emit_Ptr + 1;
538 end Emit;
539
540 ----------------
541 -- Emit_Class --
542 ----------------
543
544 procedure Emit_Class (Bitmap : Character_Class) is
545 subtype Program31 is Program_Data (0 .. 31);
546
547 function Convert is new Ada.Unchecked_Conversion
548 (Character_Class, Program31);
549
550 begin
551 -- What is the mysterious constant 31 here??? Can't it be expressed
552 -- symbolically (size of integer - 1 or some such???). In any case
553 -- it should be declared as a constant (and referenced presumably
554 -- as this constant + 1 below.
555
556 if Emit_Ptr + 31 <= PM.Size then
557 Program (Emit_Ptr .. Emit_Ptr + 31) := Convert (Bitmap);
558 end if;
559
560 Emit_Ptr := Emit_Ptr + 32;
561 end Emit_Class;
562
563 ------------------
564 -- Emit_Natural --
565 ------------------
566
567 procedure Emit_Natural (IP : Pointer; N : Natural) is
568 begin
569 if IP + 1 <= PM.Size then
570 Program (IP + 1) := Character'Val (N / 256);
571 Program (IP) := Character'Val (N mod 256);
572 end if;
573 end Emit_Natural;
574
575 ---------------
576 -- Emit_Node --
577 ---------------
578
579 function Emit_Node (Op : Opcode) return Pointer is
580 Result : constant Pointer := Emit_Ptr;
581
582 begin
583 if Emit_Ptr + 2 <= PM.Size then
584 Program (Emit_Ptr) := Character'Val (Opcode'Pos (Op));
585 Program (Emit_Ptr + 1) := ASCII.NUL;
586 Program (Emit_Ptr + 2) := ASCII.NUL;
587 end if;
588
589 Emit_Ptr := Emit_Ptr + Next_Pointer_Bytes;
590 return Result;
591 end Emit_Node;
592
593 ----------
594 -- Fail --
595 ----------
596
597 procedure Fail (M : String) is
598 begin
599 raise Expression_Error with M;
600 end Fail;
601
602 -------------------------
603 -- Get_Curly_Arguments --
604 -------------------------
605
606 procedure Get_Curly_Arguments
607 (IP : Natural;
608 Min : out Natural;
609 Max : out Natural;
610 Greedy : out Boolean)
611 is
612 pragma Unreferenced (IP);
613
614 Save_Pos : Natural := Parse_Pos + 1;
615
616 begin
617 Min := 0;
618 Max := Max_Curly_Repeat;
619
620 while Expression (Parse_Pos) /= '}'
621 and then Expression (Parse_Pos) /= ','
622 loop
623 Parse_Pos := Parse_Pos + 1;
624 end loop;
625
626 Min := Natural'Value (Expression (Save_Pos .. Parse_Pos - 1));
627
628 if Expression (Parse_Pos) = ',' then
629 Save_Pos := Parse_Pos + 1;
630 while Expression (Parse_Pos) /= '}' loop
631 Parse_Pos := Parse_Pos + 1;
632 end loop;
633
634 if Save_Pos /= Parse_Pos then
635 Max := Natural'Value (Expression (Save_Pos .. Parse_Pos - 1));
636 end if;
637
638 else
639 Max := Min;
640 end if;
641
642 if Parse_Pos < Expression'Last
643 and then Expression (Parse_Pos + 1) = '?'
644 then
645 Greedy := False;
646 Parse_Pos := Parse_Pos + 1;
647
648 else
649 Greedy := True;
650 end if;
651 end Get_Curly_Arguments;
652
653 ---------------------------
654 -- Insert_Curly_Operator --
655 ---------------------------
656
657 procedure Insert_Curly_Operator
658 (Op : Opcode;
659 Min : Natural;
660 Max : Natural;
661 Operand : Pointer;
662 Greedy : Boolean := True)
663 is
664 Old : Pointer;
665 begin
666 Old := Insert_Operator_Before (Op, Operand, Greedy, Opsize => 7);
667 Emit_Natural (Old + Next_Pointer_Bytes, Min);
668 Emit_Natural (Old + Next_Pointer_Bytes + 2, Max);
669 end Insert_Curly_Operator;
670
671 ----------------------------
672 -- Insert_Operator_Before --
673 ----------------------------
674
675 function Insert_Operator_Before
676 (Op : Opcode;
677 Operand : Pointer;
678 Greedy : Boolean;
679 Opsize : Pointer) return Pointer
680 is
681 Dest : constant Pointer := Emit_Ptr;
682 Old : Pointer;
683 Size : Pointer := Opsize;
684
685 begin
686 -- If not greedy, we have to emit another opcode first
687
688 if not Greedy then
689 Size := Size + Next_Pointer_Bytes;
690 end if;
691
692 -- Move the operand in the byte-compilation, so that we can insert
693 -- the operator before it.
694
695 if Emit_Ptr + Size <= PM.Size then
696 Program (Operand + Size .. Emit_Ptr + Size) :=
697 Program (Operand .. Emit_Ptr);
698 end if;
699
700 -- Insert the operator at the position previously occupied by the
701 -- operand.
702
703 Emit_Ptr := Operand;
704
705 if not Greedy then
706 Old := Emit_Node (MINMOD);
707 Link_Tail (Old, Old + Next_Pointer_Bytes);
708 end if;
709
710 Old := Emit_Node (Op);
711 Emit_Ptr := Dest + Size;
712 return Old;
713 end Insert_Operator_Before;
714
715 ---------------------
716 -- Insert_Operator --
717 ---------------------
718
719 procedure Insert_Operator
720 (Op : Opcode;
721 Operand : Pointer;
722 Greedy : Boolean := True)
723 is
724 Discard : Pointer;
725 pragma Warnings (Off, Discard);
726 begin
727 Discard := Insert_Operator_Before
728 (Op, Operand, Greedy, Opsize => Next_Pointer_Bytes);
729 end Insert_Operator;
730
731 -----------------------
732 -- Is_Curly_Operator --
733 -----------------------
734
735 function Is_Curly_Operator (IP : Natural) return Boolean is
736 Scan : Natural := IP;
737
738 begin
739 if Expression (Scan) /= '{'
740 or else Scan + 2 > Expression'Last
741 or else not Is_Digit (Expression (Scan + 1))
742 then
743 return False;
744 end if;
745
746 Scan := Scan + 1;
747
748 -- The first digit
749
750 loop
751 Scan := Scan + 1;
752
753 if Scan > Expression'Last then
754 return False;
755 end if;
756
757 exit when not Is_Digit (Expression (Scan));
758 end loop;
759
760 if Expression (Scan) = ',' then
761 loop
762 Scan := Scan + 1;
763
764 if Scan > Expression'Last then
765 return False;
766 end if;
767
768 exit when not Is_Digit (Expression (Scan));
769 end loop;
770 end if;
771
772 return Expression (Scan) = '}';
773 end Is_Curly_Operator;
774
775 -------------
776 -- Is_Mult --
777 -------------
778
779 function Is_Mult (IP : Natural) return Boolean is
780 C : constant Character := Expression (IP);
781
782 begin
783 return C = '*'
784 or else C = '+'
785 or else C = '?'
786 or else (C = '{' and then Is_Curly_Operator (IP));
787 end Is_Mult;
788
789 -----------------------
790 -- Link_Operand_Tail --
791 -----------------------
792
793 procedure Link_Operand_Tail (P, Val : Pointer) is
794 begin
795 if P <= PM.Size and then Program (P) = BRANCH then
796 Link_Tail (Operand (P), Val);
797 end if;
798 end Link_Operand_Tail;
799
800 ---------------
801 -- Link_Tail --
802 ---------------
803
804 procedure Link_Tail (P, Val : Pointer) is
805 Scan : Pointer;
806 Temp : Pointer;
807 Offset : Pointer;
808
809 begin
810 -- Find last node (the size of the pattern matcher might be too
811 -- small, so don't try to read past its end).
812
813 Scan := P;
814 while Scan + Next_Pointer_Bytes <= PM.Size loop
815 Temp := Get_Next (Program, Scan);
816 exit when Temp = Scan;
817 Scan := Temp;
818 end loop;
819
820 Offset := Val - Scan;
821
822 Emit_Natural (Scan + 1, Natural (Offset));
823 end Link_Tail;
824
825 -----------
826 -- Parse --
827 -----------
828
829 -- Combining parenthesis handling with the base level of regular
830 -- expression is a trifle forced, but the need to tie the tails of the
831 -- the branches to what follows makes it hard to avoid.
832
833 procedure Parse
834 (Parenthesized : Boolean;
835 Flags : out Expression_Flags;
836 IP : out Pointer)
837 is
838 E : String renames Expression;
839 Br, Br2 : Pointer;
840 Ender : Pointer;
841 Par_No : Natural;
842 New_Flags : Expression_Flags;
843 Have_Branch : Boolean := False;
844
845 begin
846 Flags := (Has_Width => True, others => False); -- Tentatively
847
848 -- Make an OPEN node, if parenthesized
849
850 if Parenthesized then
851 if Matcher.Paren_Count > Max_Paren_Count then
852 Fail ("too many ()");
853 end if;
854
855 Par_No := Matcher.Paren_Count + 1;
856 Matcher.Paren_Count := Matcher.Paren_Count + 1;
857 IP := Emit_Node (OPEN);
858 Emit (Character'Val (Par_No));
859
860 else
861 IP := 0;
862 Par_No := 0;
863 end if;
864
865 -- Pick up the branches, linking them together
866
867 Parse_Branch (New_Flags, True, Br);
868
869 if Br = 0 then
870 IP := 0;
871 return;
872 end if;
873
874 if Parse_Pos <= Parse_End
875 and then E (Parse_Pos) = '|'
876 then
877 Insert_Operator (BRANCH, Br);
878 Have_Branch := True;
879 end if;
880
881 if IP /= 0 then
882 Link_Tail (IP, Br); -- OPEN -> first
883 else
884 IP := Br;
885 end if;
886
887 if not New_Flags.Has_Width then
888 Flags.Has_Width := False;
889 end if;
890
891 Flags.SP_Start := Flags.SP_Start or else New_Flags.SP_Start;
892
893 while Parse_Pos <= Parse_End
894 and then (E (Parse_Pos) = '|')
895 loop
896 Parse_Pos := Parse_Pos + 1;
897 Parse_Branch (New_Flags, False, Br);
898
899 if Br = 0 then
900 IP := 0;
901 return;
902 end if;
903
904 Link_Tail (IP, Br); -- BRANCH -> BRANCH
905
906 if not New_Flags.Has_Width then
907 Flags.Has_Width := False;
908 end if;
909
910 Flags.SP_Start := Flags.SP_Start or else New_Flags.SP_Start;
911 end loop;
912
913 -- Make a closing node, and hook it on the end
914
915 if Parenthesized then
916 Ender := Emit_Node (CLOSE);
917 Emit (Character'Val (Par_No));
918 else
919 Ender := Emit_Node (EOP);
920 end if;
921
922 Link_Tail (IP, Ender);
923
924 if Have_Branch and then Emit_Ptr <= PM.Size + 1 then
925
926 -- Hook the tails of the branches to the closing node
927
928 Br := IP;
929 loop
930 Link_Operand_Tail (Br, Ender);
931 Br2 := Get_Next (Program, Br);
932 exit when Br2 = Br;
933 Br := Br2;
934 end loop;
935 end if;
936
937 -- Check for proper termination
938
939 if Parenthesized then
940 if Parse_Pos > Parse_End or else E (Parse_Pos) /= ')' then
941 Fail ("unmatched ()");
942 end if;
943
944 Parse_Pos := Parse_Pos + 1;
945
946 elsif Parse_Pos <= Parse_End then
947 if E (Parse_Pos) = ')' then
948 Fail ("unmatched ()");
949 else
950 Fail ("junk on end"); -- "Can't happen"
951 end if;
952 end if;
953 end Parse;
954
955 ----------------
956 -- Parse_Atom --
957 ----------------
958
959 procedure Parse_Atom
960 (Expr_Flags : out Expression_Flags;
961 IP : out Pointer)
962 is
963 C : Character;
964
965 begin
966 -- Tentatively set worst expression case
967
968 Expr_Flags := Worst_Expression;
969
970 C := Expression (Parse_Pos);
971 Parse_Pos := Parse_Pos + 1;
972
973 case (C) is
974 when '^' =>
975 IP :=
976 Emit_Node
977 (if (Flags and Multiple_Lines) /= 0 then MBOL
978 elsif (Flags and Single_Line) /= 0 then SBOL
979 else BOL);
980
981 when '$' =>
982 IP :=
983 Emit_Node
984 (if (Flags and Multiple_Lines) /= 0 then MEOL
985 elsif (Flags and Single_Line) /= 0 then SEOL
986 else EOL);
987
988 when '.' =>
989 IP :=
990 Emit_Node
991 (if (Flags and Single_Line) /= 0 then SANY else ANY);
992
993 Expr_Flags.Has_Width := True;
994 Expr_Flags.Simple := True;
995
996 when '[' =>
997 Parse_Character_Class (IP);
998 Expr_Flags.Has_Width := True;
999 Expr_Flags.Simple := True;
1000
1001 when '(' =>
1002 declare
1003 New_Flags : Expression_Flags;
1004
1005 begin
1006 Parse (True, New_Flags, IP);
1007
1008 if IP = 0 then
1009 return;
1010 end if;
1011
1012 Expr_Flags.Has_Width :=
1013 Expr_Flags.Has_Width or else New_Flags.Has_Width;
1014 Expr_Flags.SP_Start :=
1015 Expr_Flags.SP_Start or else New_Flags.SP_Start;
1016 end;
1017
1018 when '|' | ASCII.LF | ')' =>
1019 Fail ("internal urp"); -- Supposed to be caught earlier
1020
1021 when '?' | '+' | '*' =>
1022 Fail (C & " follows nothing");
1023
1024 when '{' =>
1025 if Is_Curly_Operator (Parse_Pos - 1) then
1026 Fail (C & " follows nothing");
1027 else
1028 Parse_Literal (Expr_Flags, IP);
1029 end if;
1030
1031 when '\' =>
1032 if Parse_Pos > Parse_End then
1033 Fail ("trailing \");
1034 end if;
1035
1036 Parse_Pos := Parse_Pos + 1;
1037
1038 case Expression (Parse_Pos - 1) is
1039 when 'b' =>
1040 IP := Emit_Node (BOUND);
1041
1042 when 'B' =>
1043 IP := Emit_Node (NBOUND);
1044
1045 when 's' =>
1046 IP := Emit_Node (SPACE);
1047 Expr_Flags.Simple := True;
1048 Expr_Flags.Has_Width := True;
1049
1050 when 'S' =>
1051 IP := Emit_Node (NSPACE);
1052 Expr_Flags.Simple := True;
1053 Expr_Flags.Has_Width := True;
1054
1055 when 'd' =>
1056 IP := Emit_Node (DIGIT);
1057 Expr_Flags.Simple := True;
1058 Expr_Flags.Has_Width := True;
1059
1060 when 'D' =>
1061 IP := Emit_Node (NDIGIT);
1062 Expr_Flags.Simple := True;
1063 Expr_Flags.Has_Width := True;
1064
1065 when 'w' =>
1066 IP := Emit_Node (ALNUM);
1067 Expr_Flags.Simple := True;
1068 Expr_Flags.Has_Width := True;
1069
1070 when 'W' =>
1071 IP := Emit_Node (NALNUM);
1072 Expr_Flags.Simple := True;
1073 Expr_Flags.Has_Width := True;
1074
1075 when 'A' =>
1076 IP := Emit_Node (SBOL);
1077
1078 when 'G' =>
1079 IP := Emit_Node (SEOL);
1080
1081 when '0' .. '9' =>
1082 IP := Emit_Node (REFF);
1083
1084 declare
1085 Save : constant Natural := Parse_Pos - 1;
1086
1087 begin
1088 while Parse_Pos <= Expression'Last
1089 and then Is_Digit (Expression (Parse_Pos))
1090 loop
1091 Parse_Pos := Parse_Pos + 1;
1092 end loop;
1093
1094 Emit (Character'Val (Natural'Value
1095 (Expression (Save .. Parse_Pos - 1))));
1096 end;
1097
1098 when others =>
1099 Parse_Pos := Parse_Pos - 1;
1100 Parse_Literal (Expr_Flags, IP);
1101 end case;
1102
1103 when others =>
1104 Parse_Literal (Expr_Flags, IP);
1105 end case;
1106 end Parse_Atom;
1107
1108 ------------------
1109 -- Parse_Branch --
1110 ------------------
1111
1112 procedure Parse_Branch
1113 (Flags : out Expression_Flags;
1114 First : Boolean;
1115 IP : out Pointer)
1116 is
1117 E : String renames Expression;
1118 Chain : Pointer;
1119 Last : Pointer;
1120 New_Flags : Expression_Flags;
1121
1122 Discard : Pointer;
1123 pragma Warnings (Off, Discard);
1124
1125 begin
1126 Flags := Worst_Expression; -- Tentatively
1127 IP := (if First then Emit_Ptr else Emit_Node (BRANCH));
1128
1129 Chain := 0;
1130 while Parse_Pos <= Parse_End
1131 and then E (Parse_Pos) /= ')'
1132 and then E (Parse_Pos) /= ASCII.LF
1133 and then E (Parse_Pos) /= '|'
1134 loop
1135 Parse_Piece (New_Flags, Last);
1136
1137 if Last = 0 then
1138 IP := 0;
1139 return;
1140 end if;
1141
1142 Flags.Has_Width := Flags.Has_Width or else New_Flags.Has_Width;
1143
1144 if Chain = 0 then -- First piece
1145 Flags.SP_Start := Flags.SP_Start or else New_Flags.SP_Start;
1146 else
1147 Link_Tail (Chain, Last);
1148 end if;
1149
1150 Chain := Last;
1151 end loop;
1152
1153 -- Case where loop ran zero CURLY
1154
1155 if Chain = 0 then
1156 Discard := Emit_Node (NOTHING);
1157 end if;
1158 end Parse_Branch;
1159
1160 ---------------------------
1161 -- Parse_Character_Class --
1162 ---------------------------
1163
1164 procedure Parse_Character_Class (IP : out Pointer) is
1165 Bitmap : Character_Class;
1166 Invert : Boolean := False;
1167 In_Range : Boolean := False;
1168 Named_Class : Std_Class := ANYOF_NONE;
1169 Value : Character;
1170 Last_Value : Character := ASCII.NUL;
1171
1172 begin
1173 Reset_Class (Bitmap);
1174
1175 -- Do we have an invert character class ?
1176
1177 if Parse_Pos <= Parse_End
1178 and then Expression (Parse_Pos) = '^'
1179 then
1180 Invert := True;
1181 Parse_Pos := Parse_Pos + 1;
1182 end if;
1183
1184 -- First character can be ] or - without closing the class
1185
1186 if Parse_Pos <= Parse_End
1187 and then (Expression (Parse_Pos) = ']'
1188 or else Expression (Parse_Pos) = '-')
1189 then
1190 Set_In_Class (Bitmap, Expression (Parse_Pos));
1191 Parse_Pos := Parse_Pos + 1;
1192 end if;
1193
1194 -- While we don't have the end of the class
1195
1196 while Parse_Pos <= Parse_End
1197 and then Expression (Parse_Pos) /= ']'
1198 loop
1199 Named_Class := ANYOF_NONE;
1200 Value := Expression (Parse_Pos);
1201 Parse_Pos := Parse_Pos + 1;
1202
1203 -- Do we have a Posix character class
1204 if Value = '[' then
1205 Named_Class := Parse_Posix_Character_Class;
1206
1207 elsif Value = '\' then
1208 if Parse_Pos = Parse_End then
1209 Fail ("Trailing \");
1210 end if;
1211 Value := Expression (Parse_Pos);
1212 Parse_Pos := Parse_Pos + 1;
1213
1214 case Value is
1215 when 'w' => Named_Class := ANYOF_ALNUM;
1216 when 'W' => Named_Class := ANYOF_NALNUM;
1217 when 's' => Named_Class := ANYOF_SPACE;
1218 when 'S' => Named_Class := ANYOF_NSPACE;
1219 when 'd' => Named_Class := ANYOF_DIGIT;
1220 when 'D' => Named_Class := ANYOF_NDIGIT;
1221 when 'n' => Value := ASCII.LF;
1222 when 'r' => Value := ASCII.CR;
1223 when 't' => Value := ASCII.HT;
1224 when 'f' => Value := ASCII.FF;
1225 when 'e' => Value := ASCII.ESC;
1226 when 'a' => Value := ASCII.BEL;
1227
1228 -- when 'x' => ??? hexadecimal value
1229 -- when 'c' => ??? control character
1230 -- when '0'..'9' => ??? octal character
1231
1232 when others => null;
1233 end case;
1234 end if;
1235
1236 -- Do we have a character class?
1237
1238 if Named_Class /= ANYOF_NONE then
1239
1240 -- A range like 'a-\d' or 'a-[:digit:] is not a range
1241
1242 if In_Range then
1243 Set_In_Class (Bitmap, Last_Value);
1244 Set_In_Class (Bitmap, '-');
1245 In_Range := False;
1246 end if;
1247
1248 -- Expand the range
1249
1250 case Named_Class is
1251 when ANYOF_NONE => null;
1252
1253 when ANYOF_ALNUM | ANYOF_ALNUMC =>
1254 for Value in Class_Byte'Range loop
1255 if Is_Alnum (Character'Val (Value)) then
1256 Set_In_Class (Bitmap, Character'Val (Value));
1257 end if;
1258 end loop;
1259
1260 when ANYOF_NALNUM | ANYOF_NALNUMC =>
1261 for Value in Class_Byte'Range loop
1262 if not Is_Alnum (Character'Val (Value)) then
1263 Set_In_Class (Bitmap, Character'Val (Value));
1264 end if;
1265 end loop;
1266
1267 when ANYOF_SPACE =>
1268 for Value in Class_Byte'Range loop
1269 if Is_White_Space (Character'Val (Value)) then
1270 Set_In_Class (Bitmap, Character'Val (Value));
1271 end if;
1272 end loop;
1273
1274 when ANYOF_NSPACE =>
1275 for Value in Class_Byte'Range loop
1276 if not Is_White_Space (Character'Val (Value)) then
1277 Set_In_Class (Bitmap, Character'Val (Value));
1278 end if;
1279 end loop;
1280
1281 when ANYOF_DIGIT =>
1282 for Value in Class_Byte'Range loop
1283 if Is_Digit (Character'Val (Value)) then
1284 Set_In_Class (Bitmap, Character'Val (Value));
1285 end if;
1286 end loop;
1287
1288 when ANYOF_NDIGIT =>
1289 for Value in Class_Byte'Range loop
1290 if not Is_Digit (Character'Val (Value)) then
1291 Set_In_Class (Bitmap, Character'Val (Value));
1292 end if;
1293 end loop;
1294
1295 when ANYOF_ALPHA =>
1296 for Value in Class_Byte'Range loop
1297 if Is_Letter (Character'Val (Value)) then
1298 Set_In_Class (Bitmap, Character'Val (Value));
1299 end if;
1300 end loop;
1301
1302 when ANYOF_NALPHA =>
1303 for Value in Class_Byte'Range loop
1304 if not Is_Letter (Character'Val (Value)) then
1305 Set_In_Class (Bitmap, Character'Val (Value));
1306 end if;
1307 end loop;
1308
1309 when ANYOF_ASCII =>
1310 for Value in 0 .. 127 loop
1311 Set_In_Class (Bitmap, Character'Val (Value));
1312 end loop;
1313
1314 when ANYOF_NASCII =>
1315 for Value in 128 .. 255 loop
1316 Set_In_Class (Bitmap, Character'Val (Value));
1317 end loop;
1318
1319 when ANYOF_CNTRL =>
1320 for Value in Class_Byte'Range loop
1321 if Is_Control (Character'Val (Value)) then
1322 Set_In_Class (Bitmap, Character'Val (Value));
1323 end if;
1324 end loop;
1325
1326 when ANYOF_NCNTRL =>
1327 for Value in Class_Byte'Range loop
1328 if not Is_Control (Character'Val (Value)) then
1329 Set_In_Class (Bitmap, Character'Val (Value));
1330 end if;
1331 end loop;
1332
1333 when ANYOF_GRAPH =>
1334 for Value in Class_Byte'Range loop
1335 if Is_Graphic (Character'Val (Value)) then
1336 Set_In_Class (Bitmap, Character'Val (Value));
1337 end if;
1338 end loop;
1339
1340 when ANYOF_NGRAPH =>
1341 for Value in Class_Byte'Range loop
1342 if not Is_Graphic (Character'Val (Value)) then
1343 Set_In_Class (Bitmap, Character'Val (Value));
1344 end if;
1345 end loop;
1346
1347 when ANYOF_LOWER =>
1348 for Value in Class_Byte'Range loop
1349 if Is_Lower (Character'Val (Value)) then
1350 Set_In_Class (Bitmap, Character'Val (Value));
1351 end if;
1352 end loop;
1353
1354 when ANYOF_NLOWER =>
1355 for Value in Class_Byte'Range loop
1356 if not Is_Lower (Character'Val (Value)) then
1357 Set_In_Class (Bitmap, Character'Val (Value));
1358 end if;
1359 end loop;
1360
1361 when ANYOF_PRINT =>
1362 for Value in Class_Byte'Range loop
1363 if Is_Printable (Character'Val (Value)) then
1364 Set_In_Class (Bitmap, Character'Val (Value));
1365 end if;
1366 end loop;
1367
1368 when ANYOF_NPRINT =>
1369 for Value in Class_Byte'Range loop
1370 if not Is_Printable (Character'Val (Value)) then
1371 Set_In_Class (Bitmap, Character'Val (Value));
1372 end if;
1373 end loop;
1374
1375 when ANYOF_PUNCT =>
1376 for Value in Class_Byte'Range loop
1377 if Is_Printable (Character'Val (Value))
1378 and then not Is_White_Space (Character'Val (Value))
1379 and then not Is_Alnum (Character'Val (Value))
1380 then
1381 Set_In_Class (Bitmap, Character'Val (Value));
1382 end if;
1383 end loop;
1384
1385 when ANYOF_NPUNCT =>
1386 for Value in Class_Byte'Range loop
1387 if not Is_Printable (Character'Val (Value))
1388 or else Is_White_Space (Character'Val (Value))
1389 or else Is_Alnum (Character'Val (Value))
1390 then
1391 Set_In_Class (Bitmap, Character'Val (Value));
1392 end if;
1393 end loop;
1394
1395 when ANYOF_UPPER =>
1396 for Value in Class_Byte'Range loop
1397 if Is_Upper (Character'Val (Value)) then
1398 Set_In_Class (Bitmap, Character'Val (Value));
1399 end if;
1400 end loop;
1401
1402 when ANYOF_NUPPER =>
1403 for Value in Class_Byte'Range loop
1404 if not Is_Upper (Character'Val (Value)) then
1405 Set_In_Class (Bitmap, Character'Val (Value));
1406 end if;
1407 end loop;
1408
1409 when ANYOF_XDIGIT =>
1410 for Value in Class_Byte'Range loop
1411 if Is_Hexadecimal_Digit (Character'Val (Value)) then
1412 Set_In_Class (Bitmap, Character'Val (Value));
1413 end if;
1414 end loop;
1415
1416 when ANYOF_NXDIGIT =>
1417 for Value in Class_Byte'Range loop
1418 if not Is_Hexadecimal_Digit
1419 (Character'Val (Value))
1420 then
1421 Set_In_Class (Bitmap, Character'Val (Value));
1422 end if;
1423 end loop;
1424
1425 end case;
1426
1427 -- Not a character range
1428
1429 elsif not In_Range then
1430 Last_Value := Value;
1431
1432 if Parse_Pos > Expression'Last then
1433 Fail ("Empty character class []");
1434 end if;
1435
1436 if Expression (Parse_Pos) = '-'
1437 and then Parse_Pos < Parse_End
1438 and then Expression (Parse_Pos + 1) /= ']'
1439 then
1440 Parse_Pos := Parse_Pos + 1;
1441
1442 -- Do we have a range like '\d-a' and '[:space:]-a'
1443 -- which is not a real range
1444
1445 if Named_Class /= ANYOF_NONE then
1446 Set_In_Class (Bitmap, '-');
1447 else
1448 In_Range := True;
1449 end if;
1450
1451 else
1452 Set_In_Class (Bitmap, Value);
1453
1454 end if;
1455
1456 -- Else in a character range
1457
1458 else
1459 if Last_Value > Value then
1460 Fail ("Invalid Range [" & Last_Value'Img
1461 & "-" & Value'Img & "]");
1462 end if;
1463
1464 while Last_Value <= Value loop
1465 Set_In_Class (Bitmap, Last_Value);
1466 Last_Value := Character'Succ (Last_Value);
1467 end loop;
1468
1469 In_Range := False;
1470
1471 end if;
1472
1473 end loop;
1474
1475 -- Optimize case-insensitive ranges (put the upper case or lower
1476 -- case character into the bitmap)
1477
1478 if (Flags and Case_Insensitive) /= 0 then
1479 for C in Character'Range loop
1480 if Get_From_Class (Bitmap, C) then
1481 Set_In_Class (Bitmap, To_Lower (C));
1482 Set_In_Class (Bitmap, To_Upper (C));
1483 end if;
1484 end loop;
1485 end if;
1486
1487 -- Optimize inverted classes
1488
1489 if Invert then
1490 for J in Bitmap'Range loop
1491 Bitmap (J) := not Bitmap (J);
1492 end loop;
1493 end if;
1494
1495 Parse_Pos := Parse_Pos + 1;
1496
1497 -- Emit the class
1498
1499 IP := Emit_Node (ANYOF);
1500 Emit_Class (Bitmap);
1501 end Parse_Character_Class;
1502
1503 -------------------
1504 -- Parse_Literal --
1505 -------------------
1506
1507 -- This is a bit tricky due to quoted chars and due to
1508 -- the multiplier characters '*', '+', and '?' that
1509 -- take the SINGLE char previous as their operand.
1510
1511 -- On entry, the character at Parse_Pos - 1 is going to go
1512 -- into the string, no matter what it is. It could be
1513 -- following a \ if Parse_Atom was entered from the '\' case.
1514
1515 -- Basic idea is to pick up a good char in C and examine
1516 -- the next char. If Is_Mult (C) then twiddle, if it's a \
1517 -- then frozzle and if it's another magic char then push C and
1518 -- terminate the string. If none of the above, push C on the
1519 -- string and go around again.
1520
1521 -- Start_Pos is used to remember where "the current character"
1522 -- starts in the string, if due to an Is_Mult we need to back
1523 -- up and put the current char in a separate 1-character string.
1524 -- When Start_Pos is 0, C is the only char in the string;
1525 -- this is used in Is_Mult handling, and in setting the SIMPLE
1526 -- flag at the end.
1527
1528 procedure Parse_Literal
1529 (Expr_Flags : out Expression_Flags;
1530 IP : out Pointer)
1531 is
1532 Start_Pos : Natural := 0;
1533 C : Character;
1534 Length_Ptr : Pointer;
1535
1536 Has_Special_Operator : Boolean := False;
1537
1538 begin
1539 Parse_Pos := Parse_Pos - 1; -- Look at current character
1540
1541 IP :=
1542 Emit_Node
1543 (if (Flags and Case_Insensitive) /= 0 then EXACTF else EXACT);
1544
1545 Length_Ptr := Emit_Ptr;
1546 Emit_Ptr := String_Operand (IP);
1547
1548 Parse_Loop :
1549 loop
1550 C := Expression (Parse_Pos); -- Get current character
1551
1552 case C is
1553 when '.' | '[' | '(' | ')' | '|' | ASCII.LF | '$' | '^' =>
1554
1555 if Start_Pos = 0 then
1556 Start_Pos := Parse_Pos;
1557 Emit (C); -- First character is always emitted
1558 else
1559 exit Parse_Loop; -- Else we are done
1560 end if;
1561
1562 when '?' | '+' | '*' | '{' =>
1563
1564 if Start_Pos = 0 then
1565 Start_Pos := Parse_Pos;
1566 Emit (C); -- First character is always emitted
1567
1568 -- Are we looking at an operator, or is this
1569 -- simply a normal character ?
1570
1571 elsif not Is_Mult (Parse_Pos) then
1572 Start_Pos := Parse_Pos;
1573 Case_Emit (C);
1574
1575 else
1576 -- We've got something like "abc?d". Mark this as a
1577 -- special case. What we want to emit is a first
1578 -- constant string for "ab", then one for "c" that will
1579 -- ultimately be transformed with a CURLY operator, A
1580 -- special case has to be handled for "a?", since there
1581 -- is no initial string to emit.
1582
1583 Has_Special_Operator := True;
1584 exit Parse_Loop;
1585 end if;
1586
1587 when '\' =>
1588 Start_Pos := Parse_Pos;
1589
1590 if Parse_Pos = Parse_End then
1591 Fail ("Trailing \");
1592
1593 else
1594 case Expression (Parse_Pos + 1) is
1595 when 'b' | 'B' | 's' | 'S' | 'd' | 'D'
1596 | 'w' | 'W' | '0' .. '9' | 'G' | 'A'
1597 => exit Parse_Loop;
1598 when 'n' => Emit (ASCII.LF);
1599 when 't' => Emit (ASCII.HT);
1600 when 'r' => Emit (ASCII.CR);
1601 when 'f' => Emit (ASCII.FF);
1602 when 'e' => Emit (ASCII.ESC);
1603 when 'a' => Emit (ASCII.BEL);
1604 when others => Emit (Expression (Parse_Pos + 1));
1605 end case;
1606
1607 Parse_Pos := Parse_Pos + 1;
1608 end if;
1609
1610 when others =>
1611 Start_Pos := Parse_Pos;
1612 Case_Emit (C);
1613 end case;
1614
1615 exit Parse_Loop when Emit_Ptr - Length_Ptr = 254;
1616
1617 Parse_Pos := Parse_Pos + 1;
1618
1619 exit Parse_Loop when Parse_Pos > Parse_End;
1620 end loop Parse_Loop;
1621
1622 -- Is the string followed by a '*+?{' operator ? If yes, and if there
1623 -- is an initial string to emit, do it now.
1624
1625 if Has_Special_Operator
1626 and then Emit_Ptr >= Length_Ptr + Next_Pointer_Bytes
1627 then
1628 Emit_Ptr := Emit_Ptr - 1;
1629 Parse_Pos := Start_Pos;
1630 end if;
1631
1632 if Length_Ptr <= PM.Size then
1633 Program (Length_Ptr) := Character'Val (Emit_Ptr - Length_Ptr - 2);
1634 end if;
1635
1636 Expr_Flags.Has_Width := True;
1637
1638 -- Slight optimization when there is a single character
1639
1640 if Emit_Ptr = Length_Ptr + 2 then
1641 Expr_Flags.Simple := True;
1642 end if;
1643 end Parse_Literal;
1644
1645 -----------------
1646 -- Parse_Piece --
1647 -----------------
1648
1649 -- Note that the branching code sequences used for '?' and the
1650 -- general cases of '*' and + are somewhat optimized: they use
1651 -- the same NOTHING node as both the endmarker for their branch
1652 -- list and the body of the last branch. It might seem that
1653 -- this node could be dispensed with entirely, but the endmarker
1654 -- role is not redundant.
1655
1656 procedure Parse_Piece
1657 (Expr_Flags : out Expression_Flags;
1658 IP : out Pointer)
1659 is
1660 Op : Character;
1661 New_Flags : Expression_Flags;
1662 Greedy : Boolean := True;
1663
1664 begin
1665 Parse_Atom (New_Flags, IP);
1666
1667 if IP = 0 then
1668 return;
1669 end if;
1670
1671 if Parse_Pos > Parse_End
1672 or else not Is_Mult (Parse_Pos)
1673 then
1674 Expr_Flags := New_Flags;
1675 return;
1676 end if;
1677
1678 Op := Expression (Parse_Pos);
1679
1680 Expr_Flags :=
1681 (if Op /= '+'
1682 then (SP_Start => True, others => False)
1683 else (Has_Width => True, others => False));
1684
1685 -- Detect non greedy operators in the easy cases
1686
1687 if Op /= '{'
1688 and then Parse_Pos + 1 <= Parse_End
1689 and then Expression (Parse_Pos + 1) = '?'
1690 then
1691 Greedy := False;
1692 Parse_Pos := Parse_Pos + 1;
1693 end if;
1694
1695 -- Generate the byte code
1696
1697 case Op is
1698 when '*' =>
1699
1700 if New_Flags.Simple then
1701 Insert_Operator (STAR, IP, Greedy);
1702 else
1703 Link_Tail (IP, Emit_Node (WHILEM));
1704 Insert_Curly_Operator
1705 (CURLYX, 0, Max_Curly_Repeat, IP, Greedy);
1706 Link_Tail (IP, Emit_Node (NOTHING));
1707 end if;
1708
1709 when '+' =>
1710
1711 if New_Flags.Simple then
1712 Insert_Operator (PLUS, IP, Greedy);
1713 else
1714 Link_Tail (IP, Emit_Node (WHILEM));
1715 Insert_Curly_Operator
1716 (CURLYX, 1, Max_Curly_Repeat, IP, Greedy);
1717 Link_Tail (IP, Emit_Node (NOTHING));
1718 end if;
1719
1720 when '?' =>
1721 if New_Flags.Simple then
1722 Insert_Curly_Operator (CURLY, 0, 1, IP, Greedy);
1723 else
1724 Link_Tail (IP, Emit_Node (WHILEM));
1725 Insert_Curly_Operator (CURLYX, 0, 1, IP, Greedy);
1726 Link_Tail (IP, Emit_Node (NOTHING));
1727 end if;
1728
1729 when '{' =>
1730 declare
1731 Min, Max : Natural;
1732
1733 begin
1734 Get_Curly_Arguments (Parse_Pos, Min, Max, Greedy);
1735
1736 if New_Flags.Simple then
1737 Insert_Curly_Operator (CURLY, Min, Max, IP, Greedy);
1738 else
1739 Link_Tail (IP, Emit_Node (WHILEM));
1740 Insert_Curly_Operator (CURLYX, Min, Max, IP, Greedy);
1741 Link_Tail (IP, Emit_Node (NOTHING));
1742 end if;
1743 end;
1744
1745 when others =>
1746 null;
1747 end case;
1748
1749 Parse_Pos := Parse_Pos + 1;
1750
1751 if Parse_Pos <= Parse_End
1752 and then Is_Mult (Parse_Pos)
1753 then
1754 Fail ("nested *+{");
1755 end if;
1756 end Parse_Piece;
1757
1758 ---------------------------------
1759 -- Parse_Posix_Character_Class --
1760 ---------------------------------
1761
1762 function Parse_Posix_Character_Class return Std_Class is
1763 Invert : Boolean := False;
1764 Class : Std_Class := ANYOF_NONE;
1765 E : String renames Expression;
1766
1767 -- Class names. Note that code assumes that the length of all
1768 -- classes starting with the same letter have the same length.
1769
1770 Alnum : constant String := "alnum:]";
1771 Alpha : constant String := "alpha:]";
1772 Ascii_C : constant String := "ascii:]";
1773 Cntrl : constant String := "cntrl:]";
1774 Digit : constant String := "digit:]";
1775 Graph : constant String := "graph:]";
1776 Lower : constant String := "lower:]";
1777 Print : constant String := "print:]";
1778 Punct : constant String := "punct:]";
1779 Space : constant String := "space:]";
1780 Upper : constant String := "upper:]";
1781 Word : constant String := "word:]";
1782 Xdigit : constant String := "xdigit:]";
1783
1784 begin
1785 -- Case of character class specified
1786
1787 if Parse_Pos <= Parse_End
1788 and then Expression (Parse_Pos) = ':'
1789 then
1790 Parse_Pos := Parse_Pos + 1;
1791
1792 -- Do we have something like: [[:^alpha:]]
1793
1794 if Parse_Pos <= Parse_End
1795 and then Expression (Parse_Pos) = '^'
1796 then
1797 Invert := True;
1798 Parse_Pos := Parse_Pos + 1;
1799 end if;
1800
1801 -- Check for class names based on first letter
1802
1803 case Expression (Parse_Pos) is
1804 when 'a' =>
1805
1806 -- All 'a' classes have the same length (Alnum'Length)
1807
1808 if Parse_Pos + Alnum'Length - 1 <= Parse_End then
1809 if
1810 E (Parse_Pos .. Parse_Pos + Alnum'Length - 1) = Alnum
1811 then
1812 Class :=
1813 (if Invert then ANYOF_NALNUMC else ANYOF_ALNUMC);
1814 Parse_Pos := Parse_Pos + Alnum'Length;
1815
1816 elsif
1817 E (Parse_Pos .. Parse_Pos + Alpha'Length - 1) = Alpha
1818 then
1819 Class :=
1820 (if Invert then ANYOF_NALPHA else ANYOF_ALPHA);
1821 Parse_Pos := Parse_Pos + Alpha'Length;
1822
1823 elsif E (Parse_Pos .. Parse_Pos + Ascii_C'Length - 1) =
1824 Ascii_C
1825 then
1826 Class :=
1827 (if Invert then ANYOF_NASCII else ANYOF_ASCII);
1828 Parse_Pos := Parse_Pos + Ascii_C'Length;
1829 else
1830 Fail ("Invalid character class: " & E);
1831 end if;
1832
1833 else
1834 Fail ("Invalid character class: " & E);
1835 end if;
1836
1837 when 'c' =>
1838 if Parse_Pos + Cntrl'Length - 1 <= Parse_End
1839 and then
1840 E (Parse_Pos .. Parse_Pos + Cntrl'Length - 1) = Cntrl
1841 then
1842 Class := (if Invert then ANYOF_NCNTRL else ANYOF_CNTRL);
1843 Parse_Pos := Parse_Pos + Cntrl'Length;
1844 else
1845 Fail ("Invalid character class: " & E);
1846 end if;
1847
1848 when 'd' =>
1849 if Parse_Pos + Digit'Length - 1 <= Parse_End
1850 and then
1851 E (Parse_Pos .. Parse_Pos + Digit'Length - 1) = Digit
1852 then
1853 Class := (if Invert then ANYOF_NDIGIT else ANYOF_DIGIT);
1854 Parse_Pos := Parse_Pos + Digit'Length;
1855 end if;
1856
1857 when 'g' =>
1858 if Parse_Pos + Graph'Length - 1 <= Parse_End
1859 and then
1860 E (Parse_Pos .. Parse_Pos + Graph'Length - 1) = Graph
1861 then
1862 Class := (if Invert then ANYOF_NGRAPH else ANYOF_GRAPH);
1863 Parse_Pos := Parse_Pos + Graph'Length;
1864 else
1865 Fail ("Invalid character class: " & E);
1866 end if;
1867
1868 when 'l' =>
1869 if Parse_Pos + Lower'Length - 1 <= Parse_End
1870 and then
1871 E (Parse_Pos .. Parse_Pos + Lower'Length - 1) = Lower
1872 then
1873 Class := (if Invert then ANYOF_NLOWER else ANYOF_LOWER);
1874 Parse_Pos := Parse_Pos + Lower'Length;
1875 else
1876 Fail ("Invalid character class: " & E);
1877 end if;
1878
1879 when 'p' =>
1880
1881 -- All 'p' classes have the same length
1882
1883 if Parse_Pos + Print'Length - 1 <= Parse_End then
1884 if
1885 E (Parse_Pos .. Parse_Pos + Print'Length - 1) = Print
1886 then
1887 Class :=
1888 (if Invert then ANYOF_NPRINT else ANYOF_PRINT);
1889 Parse_Pos := Parse_Pos + Print'Length;
1890
1891 elsif
1892 E (Parse_Pos .. Parse_Pos + Punct'Length - 1) = Punct
1893 then
1894 Class :=
1895 (if Invert then ANYOF_NPUNCT else ANYOF_PUNCT);
1896 Parse_Pos := Parse_Pos + Punct'Length;
1897
1898 else
1899 Fail ("Invalid character class: " & E);
1900 end if;
1901
1902 else
1903 Fail ("Invalid character class: " & E);
1904 end if;
1905
1906 when 's' =>
1907 if Parse_Pos + Space'Length - 1 <= Parse_End
1908 and then
1909 E (Parse_Pos .. Parse_Pos + Space'Length - 1) = Space
1910 then
1911 Class := (if Invert then ANYOF_NSPACE else ANYOF_SPACE);
1912 Parse_Pos := Parse_Pos + Space'Length;
1913 else
1914 Fail ("Invalid character class: " & E);
1915 end if;
1916
1917 when 'u' =>
1918 if Parse_Pos + Upper'Length - 1 <= Parse_End
1919 and then
1920 E (Parse_Pos .. Parse_Pos + Upper'Length - 1) = Upper
1921 then
1922 Class := (if Invert then ANYOF_NUPPER else ANYOF_UPPER);
1923 Parse_Pos := Parse_Pos + Upper'Length;
1924 else
1925 Fail ("Invalid character class: " & E);
1926 end if;
1927
1928 when 'w' =>
1929 if Parse_Pos + Word'Length - 1 <= Parse_End
1930 and then
1931 E (Parse_Pos .. Parse_Pos + Word'Length - 1) = Word
1932 then
1933 Class := (if Invert then ANYOF_NALNUM else ANYOF_ALNUM);
1934 Parse_Pos := Parse_Pos + Word'Length;
1935 else
1936 Fail ("Invalid character class: " & E);
1937 end if;
1938
1939 when 'x' =>
1940 if Parse_Pos + Xdigit'Length - 1 <= Parse_End
1941 and then
1942 E (Parse_Pos .. Parse_Pos + Xdigit'Length - 1) = Xdigit
1943 then
1944 Class := (if Invert then ANYOF_NXDIGIT else ANYOF_XDIGIT);
1945 Parse_Pos := Parse_Pos + Xdigit'Length;
1946
1947 else
1948 Fail ("Invalid character class: " & E);
1949 end if;
1950
1951 when others =>
1952 Fail ("Invalid character class: " & E);
1953 end case;
1954
1955 -- Character class not specified
1956
1957 else
1958 return ANYOF_NONE;
1959 end if;
1960
1961 return Class;
1962 end Parse_Posix_Character_Class;
1963
1964 -- Local Declarations
1965
1966 Result : Pointer;
1967
1968 Expr_Flags : Expression_Flags;
1969 pragma Unreferenced (Expr_Flags);
1970
1971 -- Start of processing for Compile
1972
1973 begin
1974 Parse (False, Expr_Flags, Result);
1975
1976 if Result = 0 then
1977 Fail ("Couldn't compile expression");
1978 end if;
1979
1980 Final_Code_Size := Emit_Ptr - 1;
1981
1982 -- Do we want to actually compile the expression, or simply get the
1983 -- code size ???
1984
1985 if Emit_Ptr <= PM.Size then
1986 Optimize (PM);
1987 end if;
1988
1989 PM.Flags := Flags;
1990 end Compile;
1991
1992 function Compile
1993 (Expression : String;
1994 Flags : Regexp_Flags := No_Flags) return Pattern_Matcher
1995 is
1996 -- Assume the compiled regexp will fit in 1000 chars. If it does not we
1997 -- will have to compile a second time once the correct size is known. If
1998 -- it fits, we save a significant amount of time by avoiding the second
1999 -- compilation.
2000
2001 Dummy : Pattern_Matcher (1000);
2002 Size : Program_Size;
2003
2004 begin
2005 Compile (Dummy, Expression, Size, Flags);
2006
2007 if Size <= Dummy.Size then
2008 return Pattern_Matcher'
2009 (Size => Size,
2010 First => Dummy.First,
2011 Anchored => Dummy.Anchored,
2012 Must_Have => Dummy.Must_Have,
2013 Must_Have_Length => Dummy.Must_Have_Length,
2014 Paren_Count => Dummy.Paren_Count,
2015 Flags => Dummy.Flags,
2016 Program =>
2017 Dummy.Program
2018 (Dummy.Program'First .. Dummy.Program'First + Size - 1));
2019 else
2020 -- We have to recompile now that we know the size
2021 -- ??? Can we use Ada 2005's return construct ?
2022
2023 declare
2024 Result : Pattern_Matcher (Size);
2025 begin
2026 Compile (Result, Expression, Size, Flags);
2027 return Result;
2028 end;
2029 end if;
2030 end Compile;
2031
2032 procedure Compile
2033 (Matcher : out Pattern_Matcher;
2034 Expression : String;
2035 Flags : Regexp_Flags := No_Flags)
2036 is
2037 Size : Program_Size;
2038
2039 begin
2040 Compile (Matcher, Expression, Size, Flags);
2041
2042 if Size > Matcher.Size then
2043 raise Expression_Error with "Pattern_Matcher is too small";
2044 end if;
2045 end Compile;
2046
2047 --------------------
2048 -- Dump_Operation --
2049 --------------------
2050
2051 procedure Dump_Operation
2052 (Program : Program_Data;
2053 Index : Pointer;
2054 Indent : Natural)
2055 is
2056 Current : Pointer := Index;
2057 begin
2058 Dump_Until (Program, Current, Current + 1, Indent);
2059 end Dump_Operation;
2060
2061 ----------------
2062 -- Dump_Until --
2063 ----------------
2064
2065 procedure Dump_Until
2066 (Program : Program_Data;
2067 Index : in out Pointer;
2068 Till : Pointer;
2069 Indent : Natural;
2070 Do_Print : Boolean := True)
2071 is
2072 function Image (S : String) return String;
2073 -- Remove leading space
2074
2075 -----------
2076 -- Image --
2077 -----------
2078
2079 function Image (S : String) return String is
2080 begin
2081 if S (S'First) = ' ' then
2082 return S (S'First + 1 .. S'Last);
2083 else
2084 return S;
2085 end if;
2086 end Image;
2087
2088 -- Local variables
2089
2090 Op : Opcode;
2091 Next : Pointer;
2092 Length : Pointer;
2093 Local_Indent : Natural := Indent;
2094
2095 -- Start of processing for Dump_Until
2096
2097 begin
2098 while Index < Till loop
2099 Op := Opcode'Val (Character'Pos ((Program (Index))));
2100 Next := Get_Next (Program, Index);
2101
2102 if Do_Print then
2103 declare
2104 Point : constant String := Pointer'Image (Index);
2105 begin
2106 Put ((1 .. 4 - Point'Length => ' ')
2107 & Point & ":"
2108 & (1 .. Local_Indent * 2 => ' ') & Opcode'Image (Op));
2109 end;
2110
2111 -- Print the parenthesis number
2112
2113 if Op = OPEN or else Op = CLOSE or else Op = REFF then
2114 Put (Image (Natural'Image
2115 (Character'Pos
2116 (Program (Index + Next_Pointer_Bytes)))));
2117 end if;
2118
2119 if Next = Index then
2120 Put (" (-)");
2121 else
2122 Put (" (" & Image (Pointer'Image (Next)) & ")");
2123 end if;
2124 end if;
2125
2126 case Op is
2127 when ANYOF =>
2128 declare
2129 Bitmap : Character_Class;
2130 Last : Character := ASCII.NUL;
2131 Current : Natural := 0;
2132 Current_Char : Character;
2133
2134 begin
2135 Bitmap_Operand (Program, Index, Bitmap);
2136
2137 if Do_Print then
2138 Put ("[");
2139
2140 while Current <= 255 loop
2141 Current_Char := Character'Val (Current);
2142
2143 -- First item in a range
2144
2145 if Get_From_Class (Bitmap, Current_Char) then
2146 Last := Current_Char;
2147
2148 -- Search for the last item in the range
2149
2150 loop
2151 Current := Current + 1;
2152 exit when Current > 255;
2153 Current_Char := Character'Val (Current);
2154 exit when
2155 not Get_From_Class (Bitmap, Current_Char);
2156 end loop;
2157
2158 if not Is_Graphic (Last) then
2159 Put (Last'Img);
2160 else
2161 Put (Last);
2162 end if;
2163
2164 if Character'Succ (Last) /= Current_Char then
2165 Put ("\-" & Character'Pred (Current_Char));
2166 end if;
2167
2168 else
2169 Current := Current + 1;
2170 end if;
2171 end loop;
2172
2173 Put_Line ("]");
2174 end if;
2175
2176 Index := Index + Next_Pointer_Bytes + Bitmap'Length;
2177 end;
2178
2179 when EXACT | EXACTF =>
2180 Length := String_Length (Program, Index);
2181 if Do_Print then
2182 Put (" (" & Image (Program_Size'Image (Length + 1))
2183 & " chars) <"
2184 & String (Program (String_Operand (Index)
2185 .. String_Operand (Index)
2186 + Length)));
2187 Put_Line (">");
2188 end if;
2189
2190 Index := String_Operand (Index) + Length + 1;
2191
2192 -- Node operand
2193
2194 when BRANCH | STAR | PLUS =>
2195 if Do_Print then
2196 New_Line;
2197 end if;
2198
2199 Index := Index + Next_Pointer_Bytes;
2200 Dump_Until (Program, Index, Pointer'Min (Next, Till),
2201 Local_Indent + 1, Do_Print);
2202
2203 when CURLY | CURLYX =>
2204 if Do_Print then
2205 Put_Line
2206 (" {"
2207 & Image (Natural'Image
2208 (Read_Natural (Program, Index + Next_Pointer_Bytes)))
2209 & ","
2210 & Image (Natural'Image (Read_Natural (Program, Index + 5)))
2211 & "}");
2212 end if;
2213
2214 Index := Index + 7;
2215 Dump_Until (Program, Index, Pointer'Min (Next, Till),
2216 Local_Indent + 1, Do_Print);
2217
2218 when OPEN =>
2219 if Do_Print then
2220 New_Line;
2221 end if;
2222
2223 Index := Index + 4;
2224 Local_Indent := Local_Indent + 1;
2225
2226 when CLOSE | REFF =>
2227 if Do_Print then
2228 New_Line;
2229 end if;
2230
2231 Index := Index + 4;
2232
2233 if Op = CLOSE then
2234 Local_Indent := Local_Indent - 1;
2235 end if;
2236
2237 when others =>
2238 Index := Index + Next_Pointer_Bytes;
2239
2240 if Do_Print then
2241 New_Line;
2242 end if;
2243
2244 exit when Op = EOP;
2245 end case;
2246 end loop;
2247 end Dump_Until;
2248
2249 ----------
2250 -- Dump --
2251 ----------
2252
2253 procedure Dump (Self : Pattern_Matcher) is
2254 Program : Program_Data renames Self.Program;
2255 Index : Pointer := Program'First;
2256
2257 -- Start of processing for Dump
2258
2259 begin
2260 Put_Line ("Must start with (Self.First) = "
2261 & Character'Image (Self.First));
2262
2263 if (Self.Flags and Case_Insensitive) /= 0 then
2264 Put_Line (" Case_Insensitive mode");
2265 end if;
2266
2267 if (Self.Flags and Single_Line) /= 0 then
2268 Put_Line (" Single_Line mode");
2269 end if;
2270
2271 if (Self.Flags and Multiple_Lines) /= 0 then
2272 Put_Line (" Multiple_Lines mode");
2273 end if;
2274
2275 Dump_Until (Program, Index, Self.Program'Last + 1, 0);
2276 end Dump;
2277
2278 --------------------
2279 -- Get_From_Class --
2280 --------------------
2281
2282 function Get_From_Class
2283 (Bitmap : Character_Class;
2284 C : Character) return Boolean
2285 is
2286 Value : constant Class_Byte := Character'Pos (C);
2287 begin
2288 return
2289 (Bitmap (Value / 8) and Bit_Conversion (Value mod 8)) /= 0;
2290 end Get_From_Class;
2291
2292 --------------
2293 -- Get_Next --
2294 --------------
2295
2296 function Get_Next (Program : Program_Data; IP : Pointer) return Pointer is
2297 begin
2298 return IP + Pointer (Read_Natural (Program, IP + 1));
2299 end Get_Next;
2300
2301 --------------
2302 -- Is_Alnum --
2303 --------------
2304
2305 function Is_Alnum (C : Character) return Boolean is
2306 begin
2307 return Is_Alphanumeric (C) or else C = '_';
2308 end Is_Alnum;
2309
2310 ------------------
2311 -- Is_Printable --
2312 ------------------
2313
2314 function Is_Printable (C : Character) return Boolean is
2315 begin
2316 -- Printable if space or graphic character or other whitespace
2317 -- Other white space includes (HT/LF/VT/FF/CR = codes 9-13)
2318
2319 return C in Character'Val (32) .. Character'Val (126)
2320 or else C in ASCII.HT .. ASCII.CR;
2321 end Is_Printable;
2322
2323 --------------------
2324 -- Is_White_Space --
2325 --------------------
2326
2327 function Is_White_Space (C : Character) return Boolean is
2328 begin
2329 -- Note: HT = 9, LF = 10, VT = 11, FF = 12, CR = 13
2330
2331 return C = ' ' or else C in ASCII.HT .. ASCII.CR;
2332 end Is_White_Space;
2333
2334 -----------
2335 -- Match --
2336 -----------
2337
2338 procedure Match
2339 (Self : Pattern_Matcher;
2340 Data : String;
2341 Matches : out Match_Array;
2342 Data_First : Integer := -1;
2343 Data_Last : Positive := Positive'Last)
2344 is
2345 Program : Program_Data renames Self.Program; -- Shorter notation
2346
2347 First_In_Data : constant Integer := Integer'Max (Data_First, Data'First);
2348 Last_In_Data : constant Integer := Integer'Min (Data_Last, Data'Last);
2349
2350 -- Global work variables
2351
2352 Input_Pos : Natural; -- String-input pointer
2353 BOL_Pos : Natural; -- Beginning of input, for ^ check
2354 Matched : Boolean := False; -- Until proven True
2355
2356 Matches_Full : Match_Array (0 .. Natural'Max (Self.Paren_Count,
2357 Matches'Last));
2358 -- Stores the value of all the parenthesis pairs.
2359 -- We do not use directly Matches, so that we can also use back
2360 -- references (REFF) even if Matches is too small.
2361
2362 type Natural_Array is array (Match_Count range <>) of Natural;
2363 Matches_Tmp : Natural_Array (Matches_Full'Range);
2364 -- Save the opening position of parenthesis
2365
2366 Last_Paren : Natural := 0;
2367 -- Last parenthesis seen
2368
2369 Greedy : Boolean := True;
2370 -- True if the next operator should be greedy
2371
2372 type Current_Curly_Record;
2373 type Current_Curly_Access is access all Current_Curly_Record;
2374 type Current_Curly_Record is record
2375 Paren_Floor : Natural; -- How far back to strip parenthesis data
2376 Cur : Integer; -- How many instances of scan we've matched
2377 Min : Natural; -- Minimal number of scans to match
2378 Max : Natural; -- Maximal number of scans to match
2379 Greedy : Boolean; -- Whether to work our way up or down
2380 Scan : Pointer; -- The thing to match
2381 Next : Pointer; -- What has to match after it
2382 Lastloc : Natural; -- Where we started matching this scan
2383 Old_Cc : Current_Curly_Access; -- Before we started this one
2384 end record;
2385 -- Data used to handle the curly operator and the plus and star
2386 -- operators for complex expressions.
2387
2388 Current_Curly : Current_Curly_Access := null;
2389 -- The curly currently being processed
2390
2391 -----------------------
2392 -- Local Subprograms --
2393 -----------------------
2394
2395 function Index (Start : Positive; C : Character) return Natural;
2396 -- Find character C in Data starting at Start and return position
2397
2398 function Repeat
2399 (IP : Pointer;
2400 Max : Natural := Natural'Last) return Natural;
2401 -- Repeatedly match something simple, report how many
2402 -- It only matches on things of length 1.
2403 -- Starting from Input_Pos, it matches at most Max CURLY.
2404
2405 function Try (Pos : Positive) return Boolean;
2406 -- Try to match at specific point
2407
2408 function Match (IP : Pointer) return Boolean;
2409 -- This is the main matching routine. Conceptually the strategy
2410 -- is simple: check to see whether the current node matches,
2411 -- call self recursively to see whether the rest matches,
2412 -- and then act accordingly.
2413 --
2414 -- In practice Match makes some effort to avoid recursion, in
2415 -- particular by going through "ordinary" nodes (that don't
2416 -- need to know whether the rest of the match failed) by
2417 -- using a loop instead of recursion.
2418 -- Why is the above comment part of the spec rather than body ???
2419
2420 function Match_Whilem return Boolean;
2421 -- Return True if a WHILEM matches the Current_Curly
2422
2423 function Recurse_Match (IP : Pointer; From : Natural) return Boolean;
2424 pragma Inline (Recurse_Match);
2425 -- Calls Match recursively. It saves and restores the parenthesis
2426 -- status and location in the input stream correctly, so that
2427 -- backtracking is possible
2428
2429 function Match_Simple_Operator
2430 (Op : Opcode;
2431 Scan : Pointer;
2432 Next : Pointer;
2433 Greedy : Boolean) return Boolean;
2434 -- Return True it the simple operator (possibly non-greedy) matches
2435
2436 Dump_Indent : Integer := -1;
2437 procedure Dump_Current (Scan : Pointer; Prefix : Boolean := True);
2438 procedure Dump_Error (Msg : String);
2439 -- Debug: print the current context
2440
2441 pragma Inline (Index);
2442 pragma Inline (Repeat);
2443
2444 -- These are two complex functions, but used only once
2445
2446 pragma Inline (Match_Whilem);
2447 pragma Inline (Match_Simple_Operator);
2448
2449 -----------
2450 -- Index --
2451 -----------
2452
2453 function Index (Start : Positive; C : Character) return Natural is
2454 begin
2455 for J in Start .. Last_In_Data loop
2456 if Data (J) = C then
2457 return J;
2458 end if;
2459 end loop;
2460
2461 return 0;
2462 end Index;
2463
2464 -------------------
2465 -- Recurse_Match --
2466 -------------------
2467
2468 function Recurse_Match (IP : Pointer; From : Natural) return Boolean is
2469 L : constant Natural := Last_Paren;
2470 Tmp_F : constant Match_Array :=
2471 Matches_Full (From + 1 .. Matches_Full'Last);
2472 Start : constant Natural_Array :=
2473 Matches_Tmp (From + 1 .. Matches_Tmp'Last);
2474 Input : constant Natural := Input_Pos;
2475
2476 Dump_Indent_Save : constant Integer := Dump_Indent;
2477
2478 begin
2479 if Match (IP) then
2480 return True;
2481 end if;
2482
2483 Last_Paren := L;
2484 Matches_Full (Tmp_F'Range) := Tmp_F;
2485 Matches_Tmp (Start'Range) := Start;
2486 Input_Pos := Input;
2487 Dump_Indent := Dump_Indent_Save;
2488 return False;
2489 end Recurse_Match;
2490
2491 ------------------
2492 -- Dump_Current --
2493 ------------------
2494
2495 procedure Dump_Current (Scan : Pointer; Prefix : Boolean := True) is
2496 Length : constant := 10;
2497 Pos : constant String := Integer'Image (Input_Pos);
2498
2499 begin
2500 if Prefix then
2501 Put ((1 .. 5 - Pos'Length => ' '));
2502 Put (Pos & " <"
2503 & Data (Input_Pos
2504 .. Integer'Min (Last_In_Data, Input_Pos + Length - 1)));
2505 Put ((1 .. Length - 1 - Last_In_Data + Input_Pos => ' '));
2506 Put ("> |");
2507
2508 else
2509 Put (" ");
2510 end if;
2511
2512 Dump_Operation (Program, Scan, Indent => Dump_Indent);
2513 end Dump_Current;
2514
2515 ----------------
2516 -- Dump_Error --
2517 ----------------
2518
2519 procedure Dump_Error (Msg : String) is
2520 begin
2521 Put (" | ");
2522 Put ((1 .. Dump_Indent * 2 => ' '));
2523 Put_Line (Msg);
2524 end Dump_Error;
2525
2526 -----------
2527 -- Match --
2528 -----------
2529
2530 function Match (IP : Pointer) return Boolean is
2531 Scan : Pointer := IP;
2532 Next : Pointer;
2533 Op : Opcode;
2534 Result : Boolean;
2535
2536 begin
2537 Dump_Indent := Dump_Indent + 1;
2538
2539 State_Machine :
2540 loop
2541 pragma Assert (Scan /= 0);
2542
2543 -- Determine current opcode and count its usage in debug mode
2544
2545 Op := Opcode'Val (Character'Pos (Program (Scan)));
2546
2547 -- Calculate offset of next instruction. Second character is most
2548 -- significant in Program_Data.
2549
2550 Next := Get_Next (Program, Scan);
2551
2552 if Debug then
2553 Dump_Current (Scan);
2554 end if;
2555
2556 case Op is
2557 when EOP =>
2558 Dump_Indent := Dump_Indent - 1;
2559 return True; -- Success
2560
2561 when BRANCH =>
2562 if Program (Next) /= BRANCH then
2563 Next := Operand (Scan); -- No choice, avoid recursion
2564
2565 else
2566 loop
2567 if Recurse_Match (Operand (Scan), 0) then
2568 Dump_Indent := Dump_Indent - 1;
2569 return True;
2570 end if;
2571
2572 Scan := Get_Next (Program, Scan);
2573 exit when Scan = 0 or else Program (Scan) /= BRANCH;
2574 end loop;
2575
2576 exit State_Machine;
2577 end if;
2578
2579 when NOTHING =>
2580 null;
2581
2582 when BOL =>
2583 exit State_Machine when Input_Pos /= BOL_Pos
2584 and then ((Self.Flags and Multiple_Lines) = 0
2585 or else Data (Input_Pos - 1) /= ASCII.LF);
2586
2587 when MBOL =>
2588 exit State_Machine when Input_Pos /= BOL_Pos
2589 and then Data (Input_Pos - 1) /= ASCII.LF;
2590
2591 when SBOL =>
2592 exit State_Machine when Input_Pos /= BOL_Pos;
2593
2594 when EOL =>
2595 exit State_Machine when Input_Pos <= Data'Last
2596 and then ((Self.Flags and Multiple_Lines) = 0
2597 or else Data (Input_Pos) /= ASCII.LF);
2598
2599 when MEOL =>
2600 exit State_Machine when Input_Pos <= Data'Last
2601 and then Data (Input_Pos) /= ASCII.LF;
2602
2603 when SEOL =>
2604 exit State_Machine when Input_Pos <= Data'Last;
2605
2606 when BOUND | NBOUND =>
2607
2608 -- Was last char in word ?
2609
2610 declare
2611 N : Boolean := False;
2612 Ln : Boolean := False;
2613
2614 begin
2615 if Input_Pos /= First_In_Data then
2616 N := Is_Alnum (Data (Input_Pos - 1));
2617 end if;
2618
2619 Ln :=
2620 (if Input_Pos > Last_In_Data
2621 then False
2622 else Is_Alnum (Data (Input_Pos)));
2623
2624 if Op = BOUND then
2625 if N = Ln then
2626 exit State_Machine;
2627 end if;
2628 else
2629 if N /= Ln then
2630 exit State_Machine;
2631 end if;
2632 end if;
2633 end;
2634
2635 when SPACE =>
2636 exit State_Machine when Input_Pos > Last_In_Data
2637 or else not Is_White_Space (Data (Input_Pos));
2638 Input_Pos := Input_Pos + 1;
2639
2640 when NSPACE =>
2641 exit State_Machine when Input_Pos > Last_In_Data
2642 or else Is_White_Space (Data (Input_Pos));
2643 Input_Pos := Input_Pos + 1;
2644
2645 when DIGIT =>
2646 exit State_Machine when Input_Pos > Last_In_Data
2647 or else not Is_Digit (Data (Input_Pos));
2648 Input_Pos := Input_Pos + 1;
2649
2650 when NDIGIT =>
2651 exit State_Machine when Input_Pos > Last_In_Data
2652 or else Is_Digit (Data (Input_Pos));
2653 Input_Pos := Input_Pos + 1;
2654
2655 when ALNUM =>
2656 exit State_Machine when Input_Pos > Last_In_Data
2657 or else not Is_Alnum (Data (Input_Pos));
2658 Input_Pos := Input_Pos + 1;
2659
2660 when NALNUM =>
2661 exit State_Machine when Input_Pos > Last_In_Data
2662 or else Is_Alnum (Data (Input_Pos));
2663 Input_Pos := Input_Pos + 1;
2664
2665 when ANY =>
2666 exit State_Machine when Input_Pos > Last_In_Data
2667 or else Data (Input_Pos) = ASCII.LF;
2668 Input_Pos := Input_Pos + 1;
2669
2670 when SANY =>
2671 exit State_Machine when Input_Pos > Last_In_Data;
2672 Input_Pos := Input_Pos + 1;
2673
2674 when EXACT =>
2675 declare
2676 Opnd : Pointer := String_Operand (Scan);
2677 Current : Positive := Input_Pos;
2678 Last : constant Pointer :=
2679 Opnd + String_Length (Program, Scan);
2680
2681 begin
2682 while Opnd <= Last loop
2683 exit State_Machine when Current > Last_In_Data
2684 or else Program (Opnd) /= Data (Current);
2685 Current := Current + 1;
2686 Opnd := Opnd + 1;
2687 end loop;
2688
2689 Input_Pos := Current;
2690 end;
2691
2692 when EXACTF =>
2693 declare
2694 Opnd : Pointer := String_Operand (Scan);
2695 Current : Positive := Input_Pos;
2696
2697 Last : constant Pointer :=
2698 Opnd + String_Length (Program, Scan);
2699
2700 begin
2701 while Opnd <= Last loop
2702 exit State_Machine when Current > Last_In_Data
2703 or else Program (Opnd) /= To_Lower (Data (Current));
2704 Current := Current + 1;
2705 Opnd := Opnd + 1;
2706 end loop;
2707
2708 Input_Pos := Current;
2709 end;
2710
2711 when ANYOF =>
2712 declare
2713 Bitmap : Character_Class;
2714 begin
2715 Bitmap_Operand (Program, Scan, Bitmap);
2716 exit State_Machine when Input_Pos > Last_In_Data
2717 or else not Get_From_Class (Bitmap, Data (Input_Pos));
2718 Input_Pos := Input_Pos + 1;
2719 end;
2720
2721 when OPEN =>
2722 declare
2723 No : constant Natural :=
2724 Character'Pos (Program (Operand (Scan)));
2725 begin
2726 Matches_Tmp (No) := Input_Pos;
2727 end;
2728
2729 when CLOSE =>
2730 declare
2731 No : constant Natural :=
2732 Character'Pos (Program (Operand (Scan)));
2733
2734 begin
2735 Matches_Full (No) := (Matches_Tmp (No), Input_Pos - 1);
2736
2737 if Last_Paren < No then
2738 Last_Paren := No;
2739 end if;
2740 end;
2741
2742 when REFF =>
2743 declare
2744 No : constant Natural :=
2745 Character'Pos (Program (Operand (Scan)));
2746
2747 Data_Pos : Natural;
2748
2749 begin
2750 -- If we haven't seen that parenthesis yet
2751
2752 if Last_Paren < No then
2753 Dump_Indent := Dump_Indent - 1;
2754
2755 if Debug then
2756 Dump_Error ("REFF: No match, backtracking");
2757 end if;
2758
2759 return False;
2760 end if;
2761
2762 Data_Pos := Matches_Full (No).First;
2763
2764 while Data_Pos <= Matches_Full (No).Last loop
2765 if Input_Pos > Last_In_Data
2766 or else Data (Input_Pos) /= Data (Data_Pos)
2767 then
2768 Dump_Indent := Dump_Indent - 1;
2769
2770 if Debug then
2771 Dump_Error ("REFF: No match, backtracking");
2772 end if;
2773
2774 return False;
2775 end if;
2776
2777 Input_Pos := Input_Pos + 1;
2778 Data_Pos := Data_Pos + 1;
2779 end loop;
2780 end;
2781
2782 when MINMOD =>
2783 Greedy := False;
2784
2785 when STAR | PLUS | CURLY =>
2786 declare
2787 Greed : constant Boolean := Greedy;
2788 begin
2789 Greedy := True;
2790 Result := Match_Simple_Operator (Op, Scan, Next, Greed);
2791 Dump_Indent := Dump_Indent - 1;
2792 return Result;
2793 end;
2794
2795 when CURLYX =>
2796
2797 -- Looking at something like:
2798
2799 -- 1: CURLYX {n,m} (->4)
2800 -- 2: code for complex thing (->3)
2801 -- 3: WHILEM (->0)
2802 -- 4: NOTHING
2803
2804 declare
2805 Min : constant Natural :=
2806 Read_Natural (Program, Scan + Next_Pointer_Bytes);
2807 Max : constant Natural :=
2808 Read_Natural
2809 (Program, Scan + Next_Pointer_Bytes + 2);
2810 Cc : aliased Current_Curly_Record;
2811
2812 Has_Match : Boolean;
2813
2814 begin
2815 Cc := (Paren_Floor => Last_Paren,
2816 Cur => -1,
2817 Min => Min,
2818 Max => Max,
2819 Greedy => Greedy,
2820 Scan => Scan + 7,
2821 Next => Next,
2822 Lastloc => 0,
2823 Old_Cc => Current_Curly);
2824 Greedy := True;
2825 Current_Curly := Cc'Unchecked_Access;
2826
2827 Has_Match := Match (Next - Next_Pointer_Bytes);
2828
2829 -- Start on the WHILEM
2830
2831 Current_Curly := Cc.Old_Cc;
2832 Dump_Indent := Dump_Indent - 1;
2833
2834 if not Has_Match then
2835 if Debug then
2836 Dump_Error ("CURLYX failed...");
2837 end if;
2838 end if;
2839
2840 return Has_Match;
2841 end;
2842
2843 when WHILEM =>
2844 Result := Match_Whilem;
2845 Dump_Indent := Dump_Indent - 1;
2846
2847 if Debug and then not Result then
2848 Dump_Error ("WHILEM: no match, backtracking");
2849 end if;
2850
2851 return Result;
2852 end case;
2853
2854 Scan := Next;
2855 end loop State_Machine;
2856
2857 if Debug then
2858 Dump_Error ("failed...");
2859 Dump_Indent := Dump_Indent - 1;
2860 end if;
2861
2862 -- If we get here, there is no match. For successful matches when EOP
2863 -- is the terminating point.
2864
2865 return False;
2866 end Match;
2867
2868 ---------------------------
2869 -- Match_Simple_Operator --
2870 ---------------------------
2871
2872 function Match_Simple_Operator
2873 (Op : Opcode;
2874 Scan : Pointer;
2875 Next : Pointer;
2876 Greedy : Boolean) return Boolean
2877 is
2878 Next_Char : Character := ASCII.NUL;
2879 Next_Char_Known : Boolean := False;
2880 No : Integer; -- Can be negative
2881 Min : Natural;
2882 Max : Natural := Natural'Last;
2883 Operand_Code : Pointer;
2884 Old : Natural;
2885 Last_Pos : Natural;
2886 Save : constant Natural := Input_Pos;
2887
2888 begin
2889 -- Lookahead to avoid useless match attempts when we know what
2890 -- character comes next.
2891
2892 if Program (Next) = EXACT then
2893 Next_Char := Program (String_Operand (Next));
2894 Next_Char_Known := True;
2895 end if;
2896
2897 -- Find the minimal and maximal values for the operator
2898
2899 case Op is
2900 when STAR =>
2901 Min := 0;
2902 Operand_Code := Operand (Scan);
2903
2904 when PLUS =>
2905 Min := 1;
2906 Operand_Code := Operand (Scan);
2907
2908 when others =>
2909 Min := Read_Natural (Program, Scan + Next_Pointer_Bytes);
2910 Max := Read_Natural (Program, Scan + Next_Pointer_Bytes + 2);
2911 Operand_Code := Scan + 7;
2912 end case;
2913
2914 if Debug then
2915 Dump_Current (Operand_Code, Prefix => False);
2916 end if;
2917
2918 -- Non greedy operators
2919
2920 if not Greedy then
2921
2922 -- Test we can repeat at least Min times
2923
2924 if Min /= 0 then
2925 No := Repeat (Operand_Code, Min);
2926
2927 if No < Min then
2928 if Debug then
2929 Dump_Error ("failed... matched" & No'Img & " times");
2930 end if;
2931
2932 return False;
2933 end if;
2934 end if;
2935
2936 Old := Input_Pos;
2937
2938 -- Find the place where 'next' could work
2939
2940 if Next_Char_Known then
2941
2942 -- Last position to check
2943
2944 if Max = Natural'Last then
2945 Last_Pos := Last_In_Data;
2946 else
2947 Last_Pos := Input_Pos + Max;
2948
2949 if Last_Pos > Last_In_Data then
2950 Last_Pos := Last_In_Data;
2951 end if;
2952 end if;
2953
2954 -- Look for the first possible opportunity
2955
2956 if Debug then
2957 Dump_Error ("Next_Char must be " & Next_Char);
2958 end if;
2959
2960 loop
2961 -- Find the next possible position
2962
2963 while Input_Pos <= Last_Pos
2964 and then Data (Input_Pos) /= Next_Char
2965 loop
2966 Input_Pos := Input_Pos + 1;
2967 end loop;
2968
2969 if Input_Pos > Last_Pos then
2970 return False;
2971 end if;
2972
2973 -- Check that we still match if we stop at the position we
2974 -- just found.
2975
2976 declare
2977 Num : constant Natural := Input_Pos - Old;
2978
2979 begin
2980 Input_Pos := Old;
2981
2982 if Debug then
2983 Dump_Error ("Would we still match at that position?");
2984 end if;
2985
2986 if Repeat (Operand_Code, Num) < Num then
2987 return False;
2988 end if;
2989 end;
2990
2991 -- Input_Pos now points to the new position
2992
2993 if Match (Get_Next (Program, Scan)) then
2994 return True;
2995 end if;
2996
2997 Old := Input_Pos;
2998 Input_Pos := Input_Pos + 1;
2999 end loop;
3000
3001 -- We do not know what the next character is
3002
3003 else
3004 while Max >= Min loop
3005 if Debug then
3006 Dump_Error ("Non-greedy repeat, N=" & Min'Img);
3007 Dump_Error ("Do we still match Next if we stop here?");
3008 end if;
3009
3010 -- If the next character matches
3011
3012 if Recurse_Match (Next, 1) then
3013 return True;
3014 end if;
3015
3016 Input_Pos := Save + Min;
3017
3018 -- Could not or did not match -- move forward
3019
3020 if Repeat (Operand_Code, 1) /= 0 then
3021 Min := Min + 1;
3022 else
3023 if Debug then
3024 Dump_Error ("Non-greedy repeat failed...");
3025 end if;
3026
3027 return False;
3028 end if;
3029 end loop;
3030 end if;
3031
3032 return False;
3033
3034 -- Greedy operators
3035
3036 else
3037 No := Repeat (Operand_Code, Max);
3038
3039 if Debug and then No < Min then
3040 Dump_Error ("failed... matched" & No'Img & " times");
3041 end if;
3042
3043 -- ??? Perl has some special code here in case the next
3044 -- instruction is of type EOL, since $ and \Z can match before
3045 -- *and* after newline at the end.
3046
3047 -- ??? Perl has some special code here in case (paren) is True
3048
3049 -- Else, if we don't have any parenthesis
3050
3051 while No >= Min loop
3052 if not Next_Char_Known
3053 or else (Input_Pos <= Last_In_Data
3054 and then Data (Input_Pos) = Next_Char)
3055 then
3056 if Match (Next) then
3057 return True;
3058 end if;
3059 end if;
3060
3061 -- Could not or did not work, we back up
3062
3063 No := No - 1;
3064 Input_Pos := Save + No;
3065 end loop;
3066
3067 return False;
3068 end if;
3069 end Match_Simple_Operator;
3070
3071 ------------------
3072 -- Match_Whilem --
3073 ------------------
3074
3075 -- This is really hard to understand, because after we match what we
3076 -- are trying to match, we must make sure the rest of the REx is going
3077 -- to match for sure, and to do that we have to go back UP the parse
3078 -- tree by recursing ever deeper. And if it fails, we have to reset
3079 -- our parent's current state that we can try again after backing off.
3080
3081 function Match_Whilem return Boolean is
3082 Cc : constant Current_Curly_Access := Current_Curly;
3083
3084 N : constant Natural := Cc.Cur + 1;
3085 Ln : Natural := 0;
3086
3087 Lastloc : constant Natural := Cc.Lastloc;
3088 -- Detection of 0-len
3089
3090 begin
3091 -- If degenerate scan matches "", assume scan done
3092
3093 if Input_Pos = Cc.Lastloc
3094 and then N >= Cc.Min
3095 then
3096 -- Temporarily restore the old context, and check that we
3097 -- match was comes after CURLYX.
3098
3099 Current_Curly := Cc.Old_Cc;
3100
3101 if Current_Curly /= null then
3102 Ln := Current_Curly.Cur;
3103 end if;
3104
3105 if Match (Cc.Next) then
3106 return True;
3107 end if;
3108
3109 if Current_Curly /= null then
3110 Current_Curly.Cur := Ln;
3111 end if;
3112
3113 Current_Curly := Cc;
3114 return False;
3115 end if;
3116
3117 -- First, just match a string of min scans
3118
3119 if N < Cc.Min then
3120 Cc.Cur := N;
3121 Cc.Lastloc := Input_Pos;
3122
3123 if Debug then
3124 Dump_Error
3125 ("Tests that we match at least" & Cc.Min'Img & " N=" & N'Img);
3126 end if;
3127
3128 if Match (Cc.Scan) then
3129 return True;
3130 end if;
3131
3132 Cc.Cur := N - 1;
3133 Cc.Lastloc := Lastloc;
3134
3135 if Debug then
3136 Dump_Error ("failed...");
3137 end if;
3138
3139 return False;
3140 end if;
3141
3142 -- Prefer next over scan for minimal matching
3143
3144 if not Cc.Greedy then
3145 Current_Curly := Cc.Old_Cc;
3146
3147 if Current_Curly /= null then
3148 Ln := Current_Curly.Cur;
3149 end if;
3150
3151 if Recurse_Match (Cc.Next, Cc.Paren_Floor) then
3152 return True;
3153 end if;
3154
3155 if Current_Curly /= null then
3156 Current_Curly.Cur := Ln;
3157 end if;
3158
3159 Current_Curly := Cc;
3160
3161 -- Maximum greed exceeded ?
3162
3163 if N >= Cc.Max then
3164 if Debug then
3165 Dump_Error ("failed...");
3166 end if;
3167 return False;
3168 end if;
3169
3170 -- Try scanning more and see if it helps
3171 Cc.Cur := N;
3172 Cc.Lastloc := Input_Pos;
3173
3174 if Debug then
3175 Dump_Error ("Next failed, what about Current?");
3176 end if;
3177
3178 if Recurse_Match (Cc.Scan, Cc.Paren_Floor) then
3179 return True;
3180 end if;
3181
3182 Cc.Cur := N - 1;
3183 Cc.Lastloc := Lastloc;
3184 return False;
3185 end if;
3186
3187 -- Prefer scan over next for maximal matching
3188
3189 if N < Cc.Max then -- more greed allowed ?
3190 Cc.Cur := N;
3191 Cc.Lastloc := Input_Pos;
3192
3193 if Debug then
3194 Dump_Error ("Recurse at current position");
3195 end if;
3196
3197 if Recurse_Match (Cc.Scan, Cc.Paren_Floor) then
3198 return True;
3199 end if;
3200 end if;
3201
3202 -- Failed deeper matches of scan, so see if this one works
3203
3204 Current_Curly := Cc.Old_Cc;
3205
3206 if Current_Curly /= null then
3207 Ln := Current_Curly.Cur;
3208 end if;
3209
3210 if Debug then
3211 Dump_Error ("Failed matching for later positions");
3212 end if;
3213
3214 if Match (Cc.Next) then
3215 return True;
3216 end if;
3217
3218 if Current_Curly /= null then
3219 Current_Curly.Cur := Ln;
3220 end if;
3221
3222 Current_Curly := Cc;
3223 Cc.Cur := N - 1;
3224 Cc.Lastloc := Lastloc;
3225
3226 if Debug then
3227 Dump_Error ("failed...");
3228 end if;
3229
3230 return False;
3231 end Match_Whilem;
3232
3233 ------------
3234 -- Repeat --
3235 ------------
3236
3237 function Repeat
3238 (IP : Pointer;
3239 Max : Natural := Natural'Last) return Natural
3240 is
3241 Scan : Natural := Input_Pos;
3242 Last : Natural;
3243 Op : constant Opcode := Opcode'Val (Character'Pos (Program (IP)));
3244 Count : Natural;
3245 C : Character;
3246 Is_First : Boolean := True;
3247 Bitmap : Character_Class;
3248
3249 begin
3250 if Max = Natural'Last or else Scan + Max - 1 > Last_In_Data then
3251 Last := Last_In_Data;
3252 else
3253 Last := Scan + Max - 1;
3254 end if;
3255
3256 case Op is
3257 when ANY =>
3258 while Scan <= Last
3259 and then Data (Scan) /= ASCII.LF
3260 loop
3261 Scan := Scan + 1;
3262 end loop;
3263
3264 when SANY =>
3265 Scan := Last + 1;
3266
3267 when EXACT =>
3268
3269 -- The string has only one character if Repeat was called
3270
3271 C := Program (String_Operand (IP));
3272 while Scan <= Last
3273 and then C = Data (Scan)
3274 loop
3275 Scan := Scan + 1;
3276 end loop;
3277
3278 when EXACTF =>
3279
3280 -- The string has only one character if Repeat was called
3281
3282 C := Program (String_Operand (IP));
3283 while Scan <= Last
3284 and then To_Lower (C) = Data (Scan)
3285 loop
3286 Scan := Scan + 1;
3287 end loop;
3288
3289 when ANYOF =>
3290 if Is_First then
3291 Bitmap_Operand (Program, IP, Bitmap);
3292 Is_First := False;
3293 end if;
3294
3295 while Scan <= Last
3296 and then Get_From_Class (Bitmap, Data (Scan))
3297 loop
3298 Scan := Scan + 1;
3299 end loop;
3300
3301 when ALNUM =>
3302 while Scan <= Last
3303 and then Is_Alnum (Data (Scan))
3304 loop
3305 Scan := Scan + 1;
3306 end loop;
3307
3308 when NALNUM =>
3309 while Scan <= Last
3310 and then not Is_Alnum (Data (Scan))
3311 loop
3312 Scan := Scan + 1;
3313 end loop;
3314
3315 when SPACE =>
3316 while Scan <= Last
3317 and then Is_White_Space (Data (Scan))
3318 loop
3319 Scan := Scan + 1;
3320 end loop;
3321
3322 when NSPACE =>
3323 while Scan <= Last
3324 and then not Is_White_Space (Data (Scan))
3325 loop
3326 Scan := Scan + 1;
3327 end loop;
3328
3329 when DIGIT =>
3330 while Scan <= Last
3331 and then Is_Digit (Data (Scan))
3332 loop
3333 Scan := Scan + 1;
3334 end loop;
3335
3336 when NDIGIT =>
3337 while Scan <= Last
3338 and then not Is_Digit (Data (Scan))
3339 loop
3340 Scan := Scan + 1;
3341 end loop;
3342
3343 when others =>
3344 raise Program_Error;
3345 end case;
3346
3347 Count := Scan - Input_Pos;
3348 Input_Pos := Scan;
3349 return Count;
3350 end Repeat;
3351
3352 ---------
3353 -- Try --
3354 ---------
3355
3356 function Try (Pos : Positive) return Boolean is
3357 begin
3358 Input_Pos := Pos;
3359 Last_Paren := 0;
3360 Matches_Full := (others => No_Match);
3361
3362 if Match (Program_First) then
3363 Matches_Full (0) := (Pos, Input_Pos - 1);
3364 return True;
3365 end if;
3366
3367 return False;
3368 end Try;
3369
3370 -- Start of processing for Match
3371
3372 begin
3373 -- Do we have the regexp Never_Match?
3374
3375 if Self.Size = 0 then
3376 Matches := (others => No_Match);
3377 return;
3378 end if;
3379
3380 -- If there is a "must appear" string, look for it
3381
3382 if Self.Must_Have_Length > 0 then
3383 declare
3384 First : constant Character := Program (Self.Must_Have);
3385 Must_First : constant Pointer := Self.Must_Have;
3386 Must_Last : constant Pointer :=
3387 Must_First + Pointer (Self.Must_Have_Length - 1);
3388 Next_Try : Natural := Index (First_In_Data, First);
3389
3390 begin
3391 while Next_Try /= 0
3392 and then Data (Next_Try .. Next_Try + Self.Must_Have_Length - 1)
3393 = String (Program (Must_First .. Must_Last))
3394 loop
3395 Next_Try := Index (Next_Try + 1, First);
3396 end loop;
3397
3398 if Next_Try = 0 then
3399 Matches := (others => No_Match);
3400 return; -- Not present
3401 end if;
3402 end;
3403 end if;
3404
3405 -- Mark beginning of line for ^
3406
3407 BOL_Pos := Data'First;
3408
3409 -- Simplest case first: an anchored match need be tried only once
3410
3411 if Self.Anchored and then (Self.Flags and Multiple_Lines) = 0 then
3412 Matched := Try (First_In_Data);
3413
3414 elsif Self.Anchored then
3415 declare
3416 Next_Try : Natural := First_In_Data;
3417 begin
3418 -- Test the first position in the buffer
3419 Matched := Try (Next_Try);
3420
3421 -- Else only test after newlines
3422
3423 if not Matched then
3424 while Next_Try <= Last_In_Data loop
3425 while Next_Try <= Last_In_Data
3426 and then Data (Next_Try) /= ASCII.LF
3427 loop
3428 Next_Try := Next_Try + 1;
3429 end loop;
3430
3431 Next_Try := Next_Try + 1;
3432
3433 if Next_Try <= Last_In_Data then
3434 Matched := Try (Next_Try);
3435 exit when Matched;
3436 end if;
3437 end loop;
3438 end if;
3439 end;
3440
3441 elsif Self.First /= ASCII.NUL then
3442 -- We know what char it must start with
3443
3444 declare
3445 Next_Try : Natural := Index (First_In_Data, Self.First);
3446
3447 begin
3448 while Next_Try /= 0 loop
3449 Matched := Try (Next_Try);
3450 exit when Matched;
3451 Next_Try := Index (Next_Try + 1, Self.First);
3452 end loop;
3453 end;
3454
3455 else
3456 -- Messy cases: try all locations (including for the empty string)
3457
3458 Matched := Try (First_In_Data);
3459
3460 if not Matched then
3461 for S in First_In_Data + 1 .. Last_In_Data loop
3462 Matched := Try (S);
3463 exit when Matched;
3464 end loop;
3465 end if;
3466 end if;
3467
3468 -- Matched has its value
3469
3470 for J in Last_Paren + 1 .. Matches'Last loop
3471 Matches_Full (J) := No_Match;
3472 end loop;
3473
3474 Matches := Matches_Full (Matches'Range);
3475 end Match;
3476
3477 -----------
3478 -- Match --
3479 -----------
3480
3481 function Match
3482 (Self : Pattern_Matcher;
3483 Data : String;
3484 Data_First : Integer := -1;
3485 Data_Last : Positive := Positive'Last) return Natural
3486 is
3487 Matches : Match_Array (0 .. 0);
3488
3489 begin
3490 Match (Self, Data, Matches, Data_First, Data_Last);
3491 if Matches (0) = No_Match then
3492 return Data'First - 1;
3493 else
3494 return Matches (0).First;
3495 end if;
3496 end Match;
3497
3498 function Match
3499 (Self : Pattern_Matcher;
3500 Data : String;
3501 Data_First : Integer := -1;
3502 Data_Last : Positive := Positive'Last) return Boolean
3503 is
3504 Matches : Match_Array (0 .. 0);
3505
3506 begin
3507 Match (Self, Data, Matches, Data_First, Data_Last);
3508 return Matches (0).First >= Data'First;
3509 end Match;
3510
3511 procedure Match
3512 (Expression : String;
3513 Data : String;
3514 Matches : out Match_Array;
3515 Size : Program_Size := Auto_Size;
3516 Data_First : Integer := -1;
3517 Data_Last : Positive := Positive'Last)
3518 is
3519 PM : Pattern_Matcher (Size);
3520 Finalize_Size : Program_Size;
3521 pragma Unreferenced (Finalize_Size);
3522 begin
3523 if Size = 0 then
3524 Match (Compile (Expression), Data, Matches, Data_First, Data_Last);
3525 else
3526 Compile (PM, Expression, Finalize_Size);
3527 Match (PM, Data, Matches, Data_First, Data_Last);
3528 end if;
3529 end Match;
3530
3531 -----------
3532 -- Match --
3533 -----------
3534
3535 function Match
3536 (Expression : String;
3537 Data : String;
3538 Size : Program_Size := Auto_Size;
3539 Data_First : Integer := -1;
3540 Data_Last : Positive := Positive'Last) return Natural
3541 is
3542 PM : Pattern_Matcher (Size);
3543 Final_Size : Program_Size;
3544 pragma Unreferenced (Final_Size);
3545 begin
3546 if Size = 0 then
3547 return Match (Compile (Expression), Data, Data_First, Data_Last);
3548 else
3549 Compile (PM, Expression, Final_Size);
3550 return Match (PM, Data, Data_First, Data_Last);
3551 end if;
3552 end Match;
3553
3554 -----------
3555 -- Match --
3556 -----------
3557
3558 function Match
3559 (Expression : String;
3560 Data : String;
3561 Size : Program_Size := Auto_Size;
3562 Data_First : Integer := -1;
3563 Data_Last : Positive := Positive'Last) return Boolean
3564 is
3565 Matches : Match_Array (0 .. 0);
3566 PM : Pattern_Matcher (Size);
3567 Final_Size : Program_Size;
3568 pragma Unreferenced (Final_Size);
3569 begin
3570 if Size = 0 then
3571 Match (Compile (Expression), Data, Matches, Data_First, Data_Last);
3572 else
3573 Compile (PM, Expression, Final_Size);
3574 Match (PM, Data, Matches, Data_First, Data_Last);
3575 end if;
3576
3577 return Matches (0).First >= Data'First;
3578 end Match;
3579
3580 -------------
3581 -- Operand --
3582 -------------
3583
3584 function Operand (P : Pointer) return Pointer is
3585 begin
3586 return P + Next_Pointer_Bytes;
3587 end Operand;
3588
3589 --------------
3590 -- Optimize --
3591 --------------
3592
3593 procedure Optimize (Self : in out Pattern_Matcher) is
3594 Scan : Pointer;
3595 Program : Program_Data renames Self.Program;
3596
3597 begin
3598 -- Start with safe defaults (no optimization):
3599 -- * No known first character of match
3600 -- * Does not necessarily start at beginning of line
3601 -- * No string known that has to appear in data
3602
3603 Self.First := ASCII.NUL;
3604 Self.Anchored := False;
3605 Self.Must_Have := Program'Last + 1;
3606 Self.Must_Have_Length := 0;
3607
3608 Scan := Program_First; -- First instruction (can be anything)
3609
3610 if Program (Scan) = EXACT then
3611 Self.First := Program (String_Operand (Scan));
3612
3613 elsif Program (Scan) = BOL
3614 or else Program (Scan) = SBOL
3615 or else Program (Scan) = MBOL
3616 then
3617 Self.Anchored := True;
3618 end if;
3619 end Optimize;
3620
3621 -----------------
3622 -- Paren_Count --
3623 -----------------
3624
3625 function Paren_Count (Regexp : Pattern_Matcher) return Match_Count is
3626 begin
3627 return Regexp.Paren_Count;
3628 end Paren_Count;
3629
3630 -----------
3631 -- Quote --
3632 -----------
3633
3634 function Quote (Str : String) return String is
3635 S : String (1 .. Str'Length * 2);
3636 Last : Natural := 0;
3637
3638 begin
3639 for J in Str'Range loop
3640 case Str (J) is
3641 when '^' | '$' | '|' | '*' | '+' | '?' | '{' |
3642 '}' | '[' | ']' | '(' | ')' | '\' | '.' =>
3643
3644 S (Last + 1) := '\';
3645 S (Last + 2) := Str (J);
3646 Last := Last + 2;
3647
3648 when others =>
3649 S (Last + 1) := Str (J);
3650 Last := Last + 1;
3651 end case;
3652 end loop;
3653
3654 return S (1 .. Last);
3655 end Quote;
3656
3657 ------------------
3658 -- Read_Natural --
3659 ------------------
3660
3661 function Read_Natural
3662 (Program : Program_Data;
3663 IP : Pointer) return Natural
3664 is
3665 begin
3666 return Character'Pos (Program (IP)) +
3667 256 * Character'Pos (Program (IP + 1));
3668 end Read_Natural;
3669
3670 -----------------
3671 -- Reset_Class --
3672 -----------------
3673
3674 procedure Reset_Class (Bitmap : out Character_Class) is
3675 begin
3676 Bitmap := (others => 0);
3677 end Reset_Class;
3678
3679 ------------------
3680 -- Set_In_Class --
3681 ------------------
3682
3683 procedure Set_In_Class
3684 (Bitmap : in out Character_Class;
3685 C : Character)
3686 is
3687 Value : constant Class_Byte := Character'Pos (C);
3688 begin
3689 Bitmap (Value / 8) := Bitmap (Value / 8)
3690 or Bit_Conversion (Value mod 8);
3691 end Set_In_Class;
3692
3693 -------------------
3694 -- String_Length --
3695 -------------------
3696
3697 function String_Length
3698 (Program : Program_Data;
3699 P : Pointer) return Program_Size
3700 is
3701 begin
3702 pragma Assert (Program (P) = EXACT or else Program (P) = EXACTF);
3703 return Character'Pos (Program (P + Next_Pointer_Bytes));
3704 end String_Length;
3705
3706 --------------------
3707 -- String_Operand --
3708 --------------------
3709
3710 function String_Operand (P : Pointer) return Pointer is
3711 begin
3712 return P + 4;
3713 end String_Operand;
3714
3715 end System.Regpat;
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