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2016-10-26 François Dumont <fdumont@gcc.gnu.org>
[official-gcc.git] / gcc / ada / s-regpat.adb
blobf27639b978acc25b2f0749f7239b6fdc95ab5a9f
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) 1999-2016, 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 Capturing : Boolean;
414 Flags : out Expression_Flags;
415 IP : out Pointer);
416 -- Parse regular expression, i.e. main body or parenthesized thing.
417 -- Caller must absorb opening parenthesis. Capturing should be set to
418 -- True when we have an open parenthesis from which we want the user
419 -- to extra text.
420
421 procedure Parse_Branch
422 (Flags : out Expression_Flags;
423 First : Boolean;
424 IP : out Pointer);
425 -- Implements the concatenation operator and handles '|'.
426 -- First should be true if this is the first item of the alternative.
427
428 procedure Parse_Piece
429 (Expr_Flags : out Expression_Flags;
430 IP : out Pointer);
431 -- Parse something followed by possible [*+?]
432
433 procedure Parse_Atom
434 (Expr_Flags : out Expression_Flags;
435 IP : out Pointer);
436 -- Parse_Atom is the lowest level parse procedure.
437 --
438 -- Optimization: Gobbles an entire sequence of ordinary characters so
439 -- that it can turn them into a single node, which is smaller to store
440 -- and faster to run. Backslashed characters are exceptions, each
441 -- becoming a separate node; the code is simpler that way and it's
442 -- not worth fixing.
443
444 procedure Insert_Operator
445 (Op : Opcode;
446 Operand : Pointer;
447 Greedy : Boolean := True);
448 -- Insert_Operator inserts an operator in front of an already-emitted
449 -- operand and relocates the operand. This applies to PLUS and STAR.
450 -- If Minmod is True, then the operator is non-greedy.
451
452 function Insert_Operator_Before
453 (Op : Opcode;
454 Operand : Pointer;
455 Greedy : Boolean;
456 Opsize : Pointer) return Pointer;
457 -- Insert an operator before Operand (and move the latter forward in the
458 -- program). Opsize is the size needed to represent the operator. This
459 -- returns the position at which the operator was inserted, and moves
460 -- Emit_Ptr after the new position of the operand.
461
462 procedure Insert_Curly_Operator
463 (Op : Opcode;
464 Min : Natural;
465 Max : Natural;
466 Operand : Pointer;
467 Greedy : Boolean := True);
468 -- Insert an operator for CURLY ({Min}, {Min,} or {Min,Max}).
469 -- If Minmod is True, then the operator is non-greedy.
470
471 procedure Link_Tail (P, Val : Pointer);
472 -- Link_Tail sets the next-pointer at the end of a node chain
473
474 procedure Link_Operand_Tail (P, Val : Pointer);
475 -- Link_Tail on operand of first argument; noop if operand-less
476
477 procedure Fail (M : String);
478 pragma No_Return (Fail);
479 -- Fail with a diagnostic message, if possible
480
481 function Is_Curly_Operator (IP : Natural) return Boolean;
482 -- Return True if IP is looking at a '{' that is the beginning
483 -- of a curly operator, i.e. it matches {\d+,?\d*}
484
485 function Is_Mult (IP : Natural) return Boolean;
486 -- Return True if C is a regexp multiplier: '+', '*' or '?'
487
488 procedure Get_Curly_Arguments
489 (IP : Natural;
490 Min : out Natural;
491 Max : out Natural;
492 Greedy : out Boolean);
493 -- Parse the argument list for a curly operator.
494 -- It is assumed that IP is indeed pointing at a valid operator.
495 -- So what is IP and how come IP is not referenced in the body ???
496
497 procedure Parse_Character_Class (IP : out Pointer);
498 -- Parse a character class.
499 -- The calling subprogram should consume the opening '[' before.
500
501 procedure Parse_Literal
502 (Expr_Flags : out Expression_Flags;
503 IP : out Pointer);
504 -- Parse_Literal encodes a string of characters to be matched exactly
505
506 function Parse_Posix_Character_Class return Std_Class;
507 -- Parse a posix character class, like [:alpha:] or [:^alpha:].
508 -- The caller is supposed to absorb the opening [.
509
510 pragma Inline (Is_Mult);
511 pragma Inline (Emit_Natural);
512 pragma Inline (Parse_Character_Class); -- since used only once
513
514 ---------------
515 -- Case_Emit --
516 ---------------
517
518 procedure Case_Emit (C : Character) is
519 begin
520 if (Flags and Case_Insensitive) /= 0 then
521 Emit (To_Lower (C));
522
523 else
524 -- Dump current character
525
526 Emit (C);
527 end if;
528 end Case_Emit;
529
530 ----------
531 -- Emit --
532 ----------
533
534 procedure Emit (B : Character) is
535 begin
536 if Emit_Ptr <= PM.Size then
537 Program (Emit_Ptr) := B;
538 end if;
539
540 Emit_Ptr := Emit_Ptr + 1;
541 end Emit;
542
543 ----------------
544 -- Emit_Class --
545 ----------------
546
547 procedure Emit_Class (Bitmap : Character_Class) is
548 subtype Program31 is Program_Data (0 .. 31);
549
550 function Convert is new Ada.Unchecked_Conversion
551 (Character_Class, Program31);
552
553 begin
554 -- What is the mysterious constant 31 here??? Can't it be expressed
555 -- symbolically (size of integer - 1 or some such???). In any case
556 -- it should be declared as a constant (and referenced presumably
557 -- as this constant + 1 below.
558
559 if Emit_Ptr + 31 <= PM.Size then
560 Program (Emit_Ptr .. Emit_Ptr + 31) := Convert (Bitmap);
561 end if;
562
563 Emit_Ptr := Emit_Ptr + 32;
564 end Emit_Class;
565
566 ------------------
567 -- Emit_Natural --
568 ------------------
569
570 procedure Emit_Natural (IP : Pointer; N : Natural) is
571 begin
572 if IP + 1 <= PM.Size then
573 Program (IP + 1) := Character'Val (N / 256);
574 Program (IP) := Character'Val (N mod 256);
575 end if;
576 end Emit_Natural;
577
578 ---------------
579 -- Emit_Node --
580 ---------------
581
582 function Emit_Node (Op : Opcode) return Pointer is
583 Result : constant Pointer := Emit_Ptr;
584
585 begin
586 if Emit_Ptr + 2 <= PM.Size then
587 Program (Emit_Ptr) := Character'Val (Opcode'Pos (Op));
588 Program (Emit_Ptr + 1) := ASCII.NUL;
589 Program (Emit_Ptr + 2) := ASCII.NUL;
590 end if;
591
592 Emit_Ptr := Emit_Ptr + Next_Pointer_Bytes;
593 return Result;
594 end Emit_Node;
595
596 ----------
597 -- Fail --
598 ----------
599
600 procedure Fail (M : String) is
601 begin
602 raise Expression_Error with M;
603 end Fail;
604
605 -------------------------
606 -- Get_Curly_Arguments --
607 -------------------------
608
609 procedure Get_Curly_Arguments
610 (IP : Natural;
611 Min : out Natural;
612 Max : out Natural;
613 Greedy : out Boolean)
614 is
615 pragma Unreferenced (IP);
616
617 Save_Pos : Natural := Parse_Pos + 1;
618
619 begin
620 Min := 0;
621 Max := Max_Curly_Repeat;
622
623 while Expression (Parse_Pos) /= '}'
624 and then Expression (Parse_Pos) /= ','
625 loop
626 Parse_Pos := Parse_Pos + 1;
627 end loop;
628
629 Min := Natural'Value (Expression (Save_Pos .. Parse_Pos - 1));
630
631 if Expression (Parse_Pos) = ',' then
632 Save_Pos := Parse_Pos + 1;
633 while Expression (Parse_Pos) /= '}' loop
634 Parse_Pos := Parse_Pos + 1;
635 end loop;
636
637 if Save_Pos /= Parse_Pos then
638 Max := Natural'Value (Expression (Save_Pos .. Parse_Pos - 1));
639 end if;
640
641 else
642 Max := Min;
643 end if;
644
645 if Parse_Pos < Expression'Last
646 and then Expression (Parse_Pos + 1) = '?'
647 then
648 Greedy := False;
649 Parse_Pos := Parse_Pos + 1;
650
651 else
652 Greedy := True;
653 end if;
654 end Get_Curly_Arguments;
655
656 ---------------------------
657 -- Insert_Curly_Operator --
658 ---------------------------
659
660 procedure Insert_Curly_Operator
661 (Op : Opcode;
662 Min : Natural;
663 Max : Natural;
664 Operand : Pointer;
665 Greedy : Boolean := True)
666 is
667 Old : Pointer;
668 begin
669 Old := Insert_Operator_Before (Op, Operand, Greedy, Opsize => 7);
670 Emit_Natural (Old + Next_Pointer_Bytes, Min);
671 Emit_Natural (Old + Next_Pointer_Bytes + 2, Max);
672 end Insert_Curly_Operator;
673
674 ----------------------------
675 -- Insert_Operator_Before --
676 ----------------------------
677
678 function Insert_Operator_Before
679 (Op : Opcode;
680 Operand : Pointer;
681 Greedy : Boolean;
682 Opsize : Pointer) return Pointer
683 is
684 Dest : constant Pointer := Emit_Ptr;
685 Old : Pointer;
686 Size : Pointer := Opsize;
687
688 begin
689 -- If not greedy, we have to emit another opcode first
690
691 if not Greedy then
692 Size := Size + Next_Pointer_Bytes;
693 end if;
694
695 -- Move the operand in the byte-compilation, so that we can insert
696 -- the operator before it.
697
698 if Emit_Ptr + Size <= PM.Size then
699 Program (Operand + Size .. Emit_Ptr + Size) :=
700 Program (Operand .. Emit_Ptr);
701 end if;
702
703 -- Insert the operator at the position previously occupied by the
704 -- operand.
705
706 Emit_Ptr := Operand;
707
708 if not Greedy then
709 Old := Emit_Node (MINMOD);
710 Link_Tail (Old, Old + Next_Pointer_Bytes);
711 end if;
712
713 Old := Emit_Node (Op);
714 Emit_Ptr := Dest + Size;
715 return Old;
716 end Insert_Operator_Before;
717
718 ---------------------
719 -- Insert_Operator --
720 ---------------------
721
722 procedure Insert_Operator
723 (Op : Opcode;
724 Operand : Pointer;
725 Greedy : Boolean := True)
726 is
727 Discard : Pointer;
728 pragma Warnings (Off, Discard);
729 begin
730 Discard := Insert_Operator_Before
731 (Op, Operand, Greedy, Opsize => Next_Pointer_Bytes);
732 end Insert_Operator;
733
734 -----------------------
735 -- Is_Curly_Operator --
736 -----------------------
737
738 function Is_Curly_Operator (IP : Natural) return Boolean is
739 Scan : Natural := IP;
740
741 begin
742 if Expression (Scan) /= '{'
743 or else Scan + 2 > Expression'Last
744 or else not Is_Digit (Expression (Scan + 1))
745 then
746 return False;
747 end if;
748
749 Scan := Scan + 1;
750
751 -- The first digit
752
753 loop
754 Scan := Scan + 1;
755
756 if Scan > Expression'Last then
757 return False;
758 end if;
759
760 exit when not Is_Digit (Expression (Scan));
761 end loop;
762
763 if Expression (Scan) = ',' then
764 loop
765 Scan := Scan + 1;
766
767 if Scan > Expression'Last then
768 return False;
769 end if;
770
771 exit when not Is_Digit (Expression (Scan));
772 end loop;
773 end if;
774
775 return Expression (Scan) = '}';
776 end Is_Curly_Operator;
777
778 -------------
779 -- Is_Mult --
780 -------------
781
782 function Is_Mult (IP : Natural) return Boolean is
783 C : constant Character := Expression (IP);
784
785 begin
786 return C = '*'
787 or else C = '+'
788 or else C = '?'
789 or else (C = '{' and then Is_Curly_Operator (IP));
790 end Is_Mult;
791
792 -----------------------
793 -- Link_Operand_Tail --
794 -----------------------
795
796 procedure Link_Operand_Tail (P, Val : Pointer) is
797 begin
798 if P <= PM.Size and then Program (P) = BRANCH then
799 Link_Tail (Operand (P), Val);
800 end if;
801 end Link_Operand_Tail;
802
803 ---------------
804 -- Link_Tail --
805 ---------------
806
807 procedure Link_Tail (P, Val : Pointer) is
808 Scan : Pointer;
809 Temp : Pointer;
810 Offset : Pointer;
811
812 begin
813 -- Find last node (the size of the pattern matcher might be too
814 -- small, so don't try to read past its end).
815
816 Scan := P;
817 while Scan + Next_Pointer_Bytes <= PM.Size loop
818 Temp := Get_Next (Program, Scan);
819 exit when Temp = Scan;
820 Scan := Temp;
821 end loop;
822
823 Offset := Val - Scan;
824
825 Emit_Natural (Scan + 1, Natural (Offset));
826 end Link_Tail;
827
828 -----------
829 -- Parse --
830 -----------
831
832 -- Combining parenthesis handling with the base level of regular
833 -- expression is a trifle forced, but the need to tie the tails of the
834 -- the branches to what follows makes it hard to avoid.
835
836 procedure Parse
837 (Parenthesized : Boolean;
838 Capturing : Boolean;
839 Flags : out Expression_Flags;
840 IP : out Pointer)
841 is
842 E : String renames Expression;
843 Br, Br2 : Pointer;
844 Ender : Pointer;
845 Par_No : Natural;
846 New_Flags : Expression_Flags;
847 Have_Branch : Boolean := False;
848
849 begin
850 Flags := (Has_Width => True, others => False); -- Tentatively
851
852 -- Make an OPEN node, if parenthesized
853
854 if Parenthesized and then Capturing then
855 if Matcher.Paren_Count > Max_Paren_Count then
856 Fail ("too many ()");
857 end if;
858
859 Par_No := Matcher.Paren_Count + 1;
860 Matcher.Paren_Count := Matcher.Paren_Count + 1;
861 IP := Emit_Node (OPEN);
862 Emit (Character'Val (Par_No));
863 else
864 IP := 0;
865 Par_No := 0;
866 end if;
867
868 -- Pick up the branches, linking them together
869
870 Parse_Branch (New_Flags, True, Br);
871
872 if Br = 0 then
873 IP := 0;
874 return;
875 end if;
876
877 if Parse_Pos <= Parse_End
878 and then E (Parse_Pos) = '|'
879 then
880 Insert_Operator (BRANCH, Br);
881 Have_Branch := True;
882 end if;
883
884 if IP /= 0 then
885 Link_Tail (IP, Br); -- OPEN -> first
886 else
887 IP := Br;
888 end if;
889
890 if not New_Flags.Has_Width then
891 Flags.Has_Width := False;
892 end if;
893
894 Flags.SP_Start := Flags.SP_Start or else New_Flags.SP_Start;
895
896 while Parse_Pos <= Parse_End
897 and then (E (Parse_Pos) = '|')
898 loop
899 Parse_Pos := Parse_Pos + 1;
900 Parse_Branch (New_Flags, False, Br);
901
902 if Br = 0 then
903 IP := 0;
904 return;
905 end if;
906
907 Link_Tail (IP, Br); -- BRANCH -> BRANCH
908
909 if not New_Flags.Has_Width then
910 Flags.Has_Width := False;
911 end if;
912
913 Flags.SP_Start := Flags.SP_Start or else New_Flags.SP_Start;
914 end loop;
915
916 -- Make a closing node, and hook it on the end
917
918 if Parenthesized then
919 if Capturing then
920 Ender := Emit_Node (CLOSE);
921 Emit (Character'Val (Par_No));
922 Link_Tail (IP, Ender);
923
924 else
925 -- Need to keep looking after the closing parenthesis
926 Ender := Emit_Ptr;
927 end if;
928
929 else
930 Ender := Emit_Node (EOP);
931 Link_Tail (IP, Ender);
932 end if;
933
934 if Have_Branch and then Emit_Ptr <= PM.Size + 1 then
935
936 -- Hook the tails of the branches to the closing node
937
938 Br := IP;
939 loop
940 Link_Operand_Tail (Br, Ender);
941 Br2 := Get_Next (Program, Br);
942 exit when Br2 = Br;
943 Br := Br2;
944 end loop;
945 end if;
946
947 -- Check for proper termination
948
949 if Parenthesized then
950 if Parse_Pos > Parse_End or else E (Parse_Pos) /= ')' then
951 Fail ("unmatched ()");
952 end if;
953
954 Parse_Pos := Parse_Pos + 1;
955
956 elsif Parse_Pos <= Parse_End then
957 if E (Parse_Pos) = ')' then
958 Fail ("unmatched ')'");
959 else
960 Fail ("junk on end"); -- "Can't happen"
961 end if;
962 end if;
963 end Parse;
964
965 ----------------
966 -- Parse_Atom --
967 ----------------
968
969 procedure Parse_Atom
970 (Expr_Flags : out Expression_Flags;
971 IP : out Pointer)
972 is
973 C : Character;
974
975 begin
976 -- Tentatively set worst expression case
977
978 Expr_Flags := Worst_Expression;
979
980 C := Expression (Parse_Pos);
981 Parse_Pos := Parse_Pos + 1;
982
983 case (C) is
984 when '^' =>
985 IP :=
986 Emit_Node
987 (if (Flags and Multiple_Lines) /= 0 then MBOL
988 elsif (Flags and Single_Line) /= 0 then SBOL
989 else BOL);
990
991 when '$' =>
992 IP :=
993 Emit_Node
994 (if (Flags and Multiple_Lines) /= 0 then MEOL
995 elsif (Flags and Single_Line) /= 0 then SEOL
996 else EOL);
997
998 when '.' =>
999 IP :=
1000 Emit_Node
1001 (if (Flags and Single_Line) /= 0 then SANY else ANY);
1002
1003 Expr_Flags.Has_Width := True;
1004 Expr_Flags.Simple := True;
1005
1006 when '[' =>
1007 Parse_Character_Class (IP);
1008 Expr_Flags.Has_Width := True;
1009 Expr_Flags.Simple := True;
1010
1011 when '(' =>
1012 declare
1013 New_Flags : Expression_Flags;
1014
1015 begin
1016 if Parse_Pos <= Parse_End - 1
1017 and then Expression (Parse_Pos) = '?'
1018 and then Expression (Parse_Pos + 1) = ':'
1019 then
1020 Parse_Pos := Parse_Pos + 2;
1021
1022 -- Non-capturing parenthesis
1023
1024 Parse (True, False, New_Flags, IP);
1025
1026 else
1027 -- Capturing parenthesis
1028
1029 Parse (True, True, New_Flags, IP);
1030 Expr_Flags.Has_Width :=
1031 Expr_Flags.Has_Width or else New_Flags.Has_Width;
1032 Expr_Flags.SP_Start :=
1033 Expr_Flags.SP_Start or else New_Flags.SP_Start;
1034 if IP = 0 then
1035 return;
1036 end if;
1037 end if;
1038 end;
1039
1040 when '|' | ASCII.LF | ')' =>
1041 Fail ("internal urp"); -- Supposed to be caught earlier
1042
1043 when '?' | '+' | '*' =>
1044 Fail (C & " follows nothing");
1045
1046 when '{' =>
1047 if Is_Curly_Operator (Parse_Pos - 1) then
1048 Fail (C & " follows nothing");
1049 else
1050 Parse_Literal (Expr_Flags, IP);
1051 end if;
1052
1053 when '\' =>
1054 if Parse_Pos > Parse_End then
1055 Fail ("trailing \");
1056 end if;
1057
1058 Parse_Pos := Parse_Pos + 1;
1059
1060 case Expression (Parse_Pos - 1) is
1061 when 'b' =>
1062 IP := Emit_Node (BOUND);
1063
1064 when 'B' =>
1065 IP := Emit_Node (NBOUND);
1066
1067 when 's' =>
1068 IP := Emit_Node (SPACE);
1069 Expr_Flags.Simple := True;
1070 Expr_Flags.Has_Width := True;
1071
1072 when 'S' =>
1073 IP := Emit_Node (NSPACE);
1074 Expr_Flags.Simple := True;
1075 Expr_Flags.Has_Width := True;
1076
1077 when 'd' =>
1078 IP := Emit_Node (DIGIT);
1079 Expr_Flags.Simple := True;
1080 Expr_Flags.Has_Width := True;
1081
1082 when 'D' =>
1083 IP := Emit_Node (NDIGIT);
1084 Expr_Flags.Simple := True;
1085 Expr_Flags.Has_Width := True;
1086
1087 when 'w' =>
1088 IP := Emit_Node (ALNUM);
1089 Expr_Flags.Simple := True;
1090 Expr_Flags.Has_Width := True;
1091
1092 when 'W' =>
1093 IP := Emit_Node (NALNUM);
1094 Expr_Flags.Simple := True;
1095 Expr_Flags.Has_Width := True;
1096
1097 when 'A' =>
1098 IP := Emit_Node (SBOL);
1099
1100 when 'G' =>
1101 IP := Emit_Node (SEOL);
1102
1103 when '0' .. '9' =>
1104 IP := Emit_Node (REFF);
1105
1106 declare
1107 Save : constant Natural := Parse_Pos - 1;
1108
1109 begin
1110 while Parse_Pos <= Expression'Last
1111 and then Is_Digit (Expression (Parse_Pos))
1112 loop
1113 Parse_Pos := Parse_Pos + 1;
1114 end loop;
1115
1116 Emit (Character'Val (Natural'Value
1117 (Expression (Save .. Parse_Pos - 1))));
1118 end;
1119
1120 when others =>
1121 Parse_Pos := Parse_Pos - 1;
1122 Parse_Literal (Expr_Flags, IP);
1123 end case;
1124
1125 when others =>
1126 Parse_Literal (Expr_Flags, IP);
1127 end case;
1128 end Parse_Atom;
1129
1130 ------------------
1131 -- Parse_Branch --
1132 ------------------
1133
1134 procedure Parse_Branch
1135 (Flags : out Expression_Flags;
1136 First : Boolean;
1137 IP : out Pointer)
1138 is
1139 E : String renames Expression;
1140 Chain : Pointer;
1141 Last : Pointer;
1142 New_Flags : Expression_Flags;
1143
1144 Discard : Pointer;
1145 pragma Warnings (Off, Discard);
1146
1147 begin
1148 Flags := Worst_Expression; -- Tentatively
1149 IP := (if First then Emit_Ptr else Emit_Node (BRANCH));
1150
1151 Chain := 0;
1152 while Parse_Pos <= Parse_End
1153 and then E (Parse_Pos) /= ')'
1154 and then E (Parse_Pos) /= ASCII.LF
1155 and then E (Parse_Pos) /= '|'
1156 loop
1157 Parse_Piece (New_Flags, Last);
1158
1159 if Last = 0 then
1160 IP := 0;
1161 return;
1162 end if;
1163
1164 Flags.Has_Width := Flags.Has_Width or else New_Flags.Has_Width;
1165
1166 if Chain = 0 then -- First piece
1167 Flags.SP_Start := Flags.SP_Start or else New_Flags.SP_Start;
1168 else
1169 Link_Tail (Chain, Last);
1170 end if;
1171
1172 Chain := Last;
1173 end loop;
1174
1175 -- Case where loop ran zero CURLY
1176
1177 if Chain = 0 then
1178 Discard := Emit_Node (NOTHING);
1179 end if;
1180 end Parse_Branch;
1181
1182 ---------------------------
1183 -- Parse_Character_Class --
1184 ---------------------------
1185
1186 procedure Parse_Character_Class (IP : out Pointer) is
1187 Bitmap : Character_Class;
1188 Invert : Boolean := False;
1189 In_Range : Boolean := False;
1190 Named_Class : Std_Class := ANYOF_NONE;
1191 Value : Character;
1192 Last_Value : Character := ASCII.NUL;
1193
1194 begin
1195 Reset_Class (Bitmap);
1196
1197 -- Do we have an invert character class ?
1198
1199 if Parse_Pos <= Parse_End
1200 and then Expression (Parse_Pos) = '^'
1201 then
1202 Invert := True;
1203 Parse_Pos := Parse_Pos + 1;
1204 end if;
1205
1206 -- First character can be ] or - without closing the class
1207
1208 if Parse_Pos <= Parse_End
1209 and then (Expression (Parse_Pos) = ']'
1210 or else Expression (Parse_Pos) = '-')
1211 then
1212 Set_In_Class (Bitmap, Expression (Parse_Pos));
1213 Parse_Pos := Parse_Pos + 1;
1214 end if;
1215
1216 -- While we don't have the end of the class
1217
1218 while Parse_Pos <= Parse_End
1219 and then Expression (Parse_Pos) /= ']'
1220 loop
1221 Named_Class := ANYOF_NONE;
1222 Value := Expression (Parse_Pos);
1223 Parse_Pos := Parse_Pos + 1;
1224
1225 -- Do we have a Posix character class
1226 if Value = '[' then
1227 Named_Class := Parse_Posix_Character_Class;
1228
1229 elsif Value = '\' then
1230 if Parse_Pos = Parse_End then
1231 Fail ("Trailing \");
1232 end if;
1233 Value := Expression (Parse_Pos);
1234 Parse_Pos := Parse_Pos + 1;
1235
1236 case Value is
1237 when 'w' => Named_Class := ANYOF_ALNUM;
1238 when 'W' => Named_Class := ANYOF_NALNUM;
1239 when 's' => Named_Class := ANYOF_SPACE;
1240 when 'S' => Named_Class := ANYOF_NSPACE;
1241 when 'd' => Named_Class := ANYOF_DIGIT;
1242 when 'D' => Named_Class := ANYOF_NDIGIT;
1243 when 'n' => Value := ASCII.LF;
1244 when 'r' => Value := ASCII.CR;
1245 when 't' => Value := ASCII.HT;
1246 when 'f' => Value := ASCII.FF;
1247 when 'e' => Value := ASCII.ESC;
1248 when 'a' => Value := ASCII.BEL;
1249
1250 -- when 'x' => ??? hexadecimal value
1251 -- when 'c' => ??? control character
1252 -- when '0'..'9' => ??? octal character
1253
1254 when others => null;
1255 end case;
1256 end if;
1257
1258 -- Do we have a character class?
1259
1260 if Named_Class /= ANYOF_NONE then
1261
1262 -- A range like 'a-\d' or 'a-[:digit:] is not a range
1263
1264 if In_Range then
1265 Set_In_Class (Bitmap, Last_Value);
1266 Set_In_Class (Bitmap, '-');
1267 In_Range := False;
1268 end if;
1269
1270 -- Expand the range
1271
1272 case Named_Class is
1273 when ANYOF_NONE => null;
1274
1275 when ANYOF_ALNUM | ANYOF_ALNUMC =>
1276 for Value in Class_Byte'Range loop
1277 if Is_Alnum (Character'Val (Value)) then
1278 Set_In_Class (Bitmap, Character'Val (Value));
1279 end if;
1280 end loop;
1281
1282 when ANYOF_NALNUM | ANYOF_NALNUMC =>
1283 for Value in Class_Byte'Range loop
1284 if not Is_Alnum (Character'Val (Value)) then
1285 Set_In_Class (Bitmap, Character'Val (Value));
1286 end if;
1287 end loop;
1288
1289 when ANYOF_SPACE =>
1290 for Value in Class_Byte'Range loop
1291 if Is_White_Space (Character'Val (Value)) then
1292 Set_In_Class (Bitmap, Character'Val (Value));
1293 end if;
1294 end loop;
1295
1296 when ANYOF_NSPACE =>
1297 for Value in Class_Byte'Range loop
1298 if not Is_White_Space (Character'Val (Value)) then
1299 Set_In_Class (Bitmap, Character'Val (Value));
1300 end if;
1301 end loop;
1302
1303 when ANYOF_DIGIT =>
1304 for Value in Class_Byte'Range loop
1305 if Is_Digit (Character'Val (Value)) then
1306 Set_In_Class (Bitmap, Character'Val (Value));
1307 end if;
1308 end loop;
1309
1310 when ANYOF_NDIGIT =>
1311 for Value in Class_Byte'Range loop
1312 if not Is_Digit (Character'Val (Value)) then
1313 Set_In_Class (Bitmap, Character'Val (Value));
1314 end if;
1315 end loop;
1316
1317 when ANYOF_ALPHA =>
1318 for Value in Class_Byte'Range loop
1319 if Is_Letter (Character'Val (Value)) then
1320 Set_In_Class (Bitmap, Character'Val (Value));
1321 end if;
1322 end loop;
1323
1324 when ANYOF_NALPHA =>
1325 for Value in Class_Byte'Range loop
1326 if not Is_Letter (Character'Val (Value)) then
1327 Set_In_Class (Bitmap, Character'Val (Value));
1328 end if;
1329 end loop;
1330
1331 when ANYOF_ASCII =>
1332 for Value in 0 .. 127 loop
1333 Set_In_Class (Bitmap, Character'Val (Value));
1334 end loop;
1335
1336 when ANYOF_NASCII =>
1337 for Value in 128 .. 255 loop
1338 Set_In_Class (Bitmap, Character'Val (Value));
1339 end loop;
1340
1341 when ANYOF_CNTRL =>
1342 for Value in Class_Byte'Range loop
1343 if Is_Control (Character'Val (Value)) then
1344 Set_In_Class (Bitmap, Character'Val (Value));
1345 end if;
1346 end loop;
1347
1348 when ANYOF_NCNTRL =>
1349 for Value in Class_Byte'Range loop
1350 if not Is_Control (Character'Val (Value)) then
1351 Set_In_Class (Bitmap, Character'Val (Value));
1352 end if;
1353 end loop;
1354
1355 when ANYOF_GRAPH =>
1356 for Value in Class_Byte'Range loop
1357 if Is_Graphic (Character'Val (Value)) then
1358 Set_In_Class (Bitmap, Character'Val (Value));
1359 end if;
1360 end loop;
1361
1362 when ANYOF_NGRAPH =>
1363 for Value in Class_Byte'Range loop
1364 if not Is_Graphic (Character'Val (Value)) then
1365 Set_In_Class (Bitmap, Character'Val (Value));
1366 end if;
1367 end loop;
1368
1369 when ANYOF_LOWER =>
1370 for Value in Class_Byte'Range loop
1371 if Is_Lower (Character'Val (Value)) then
1372 Set_In_Class (Bitmap, Character'Val (Value));
1373 end if;
1374 end loop;
1375
1376 when ANYOF_NLOWER =>
1377 for Value in Class_Byte'Range loop
1378 if not Is_Lower (Character'Val (Value)) then
1379 Set_In_Class (Bitmap, Character'Val (Value));
1380 end if;
1381 end loop;
1382
1383 when ANYOF_PRINT =>
1384 for Value in Class_Byte'Range loop
1385 if Is_Printable (Character'Val (Value)) then
1386 Set_In_Class (Bitmap, Character'Val (Value));
1387 end if;
1388 end loop;
1389
1390 when ANYOF_NPRINT =>
1391 for Value in Class_Byte'Range loop
1392 if not Is_Printable (Character'Val (Value)) then
1393 Set_In_Class (Bitmap, Character'Val (Value));
1394 end if;
1395 end loop;
1396
1397 when ANYOF_PUNCT =>
1398 for Value in Class_Byte'Range loop
1399 if Is_Printable (Character'Val (Value))
1400 and then not Is_White_Space (Character'Val (Value))
1401 and then not Is_Alnum (Character'Val (Value))
1402 then
1403 Set_In_Class (Bitmap, Character'Val (Value));
1404 end if;
1405 end loop;
1406
1407 when ANYOF_NPUNCT =>
1408 for Value in Class_Byte'Range loop
1409 if not Is_Printable (Character'Val (Value))
1410 or else Is_White_Space (Character'Val (Value))
1411 or else Is_Alnum (Character'Val (Value))
1412 then
1413 Set_In_Class (Bitmap, Character'Val (Value));
1414 end if;
1415 end loop;
1416
1417 when ANYOF_UPPER =>
1418 for Value in Class_Byte'Range loop
1419 if Is_Upper (Character'Val (Value)) then
1420 Set_In_Class (Bitmap, Character'Val (Value));
1421 end if;
1422 end loop;
1423
1424 when ANYOF_NUPPER =>
1425 for Value in Class_Byte'Range loop
1426 if not Is_Upper (Character'Val (Value)) then
1427 Set_In_Class (Bitmap, Character'Val (Value));
1428 end if;
1429 end loop;
1430
1431 when ANYOF_XDIGIT =>
1432 for Value in Class_Byte'Range loop
1433 if Is_Hexadecimal_Digit (Character'Val (Value)) then
1434 Set_In_Class (Bitmap, Character'Val (Value));
1435 end if;
1436 end loop;
1437
1438 when ANYOF_NXDIGIT =>
1439 for Value in Class_Byte'Range loop
1440 if not Is_Hexadecimal_Digit
1441 (Character'Val (Value))
1442 then
1443 Set_In_Class (Bitmap, Character'Val (Value));
1444 end if;
1445 end loop;
1446
1447 end case;
1448
1449 -- Not a character range
1450
1451 elsif not In_Range then
1452 Last_Value := Value;
1453
1454 if Parse_Pos > Expression'Last then
1455 Fail ("Empty character class []");
1456 end if;
1457
1458 if Expression (Parse_Pos) = '-'
1459 and then Parse_Pos < Parse_End
1460 and then Expression (Parse_Pos + 1) /= ']'
1461 then
1462 Parse_Pos := Parse_Pos + 1;
1463
1464 -- Do we have a range like '\d-a' and '[:space:]-a'
1465 -- which is not a real range
1466
1467 if Named_Class /= ANYOF_NONE then
1468 Set_In_Class (Bitmap, '-');
1469 else
1470 In_Range := True;
1471 end if;
1472
1473 else
1474 Set_In_Class (Bitmap, Value);
1475
1476 end if;
1477
1478 -- Else in a character range
1479
1480 else
1481 if Last_Value > Value then
1482 Fail ("Invalid Range [" & Last_Value'Img
1483 & "-" & Value'Img & "]");
1484 end if;
1485
1486 while Last_Value <= Value loop
1487 Set_In_Class (Bitmap, Last_Value);
1488 Last_Value := Character'Succ (Last_Value);
1489 end loop;
1490
1491 In_Range := False;
1492
1493 end if;
1494
1495 end loop;
1496
1497 -- Optimize case-insensitive ranges (put the upper case or lower
1498 -- case character into the bitmap)
1499
1500 if (Flags and Case_Insensitive) /= 0 then
1501 for C in Character'Range loop
1502 if Get_From_Class (Bitmap, C) then
1503 Set_In_Class (Bitmap, To_Lower (C));
1504 Set_In_Class (Bitmap, To_Upper (C));
1505 end if;
1506 end loop;
1507 end if;
1508
1509 -- Optimize inverted classes
1510
1511 if Invert then
1512 for J in Bitmap'Range loop
1513 Bitmap (J) := not Bitmap (J);
1514 end loop;
1515 end if;
1516
1517 Parse_Pos := Parse_Pos + 1;
1518
1519 -- Emit the class
1520
1521 IP := Emit_Node (ANYOF);
1522 Emit_Class (Bitmap);
1523 end Parse_Character_Class;
1524
1525 -------------------
1526 -- Parse_Literal --
1527 -------------------
1528
1529 -- This is a bit tricky due to quoted chars and due to
1530 -- the multiplier characters '*', '+', and '?' that
1531 -- take the SINGLE char previous as their operand.
1532
1533 -- On entry, the character at Parse_Pos - 1 is going to go
1534 -- into the string, no matter what it is. It could be
1535 -- following a \ if Parse_Atom was entered from the '\' case.
1536
1537 -- Basic idea is to pick up a good char in C and examine
1538 -- the next char. If Is_Mult (C) then twiddle, if it's a \
1539 -- then frozzle and if it's another magic char then push C and
1540 -- terminate the string. If none of the above, push C on the
1541 -- string and go around again.
1542
1543 -- Start_Pos is used to remember where "the current character"
1544 -- starts in the string, if due to an Is_Mult we need to back
1545 -- up and put the current char in a separate 1-character string.
1546 -- When Start_Pos is 0, C is the only char in the string;
1547 -- this is used in Is_Mult handling, and in setting the SIMPLE
1548 -- flag at the end.
1549
1550 procedure Parse_Literal
1551 (Expr_Flags : out Expression_Flags;
1552 IP : out Pointer)
1553 is
1554 Start_Pos : Natural := 0;
1555 C : Character;
1556 Length_Ptr : Pointer;
1557
1558 Has_Special_Operator : Boolean := False;
1559
1560 begin
1561 Parse_Pos := Parse_Pos - 1; -- Look at current character
1562
1563 IP :=
1564 Emit_Node
1565 (if (Flags and Case_Insensitive) /= 0 then EXACTF else EXACT);
1566
1567 Length_Ptr := Emit_Ptr;
1568 Emit_Ptr := String_Operand (IP);
1569
1570 Parse_Loop :
1571 loop
1572 C := Expression (Parse_Pos); -- Get current character
1573
1574 case C is
1575 when '.' | '[' | '(' | ')' | '|' | ASCII.LF | '$' | '^' =>
1576
1577 if Start_Pos = 0 then
1578 Start_Pos := Parse_Pos;
1579 Emit (C); -- First character is always emitted
1580 else
1581 exit Parse_Loop; -- Else we are done
1582 end if;
1583
1584 when '?' | '+' | '*' | '{' =>
1585
1586 if Start_Pos = 0 then
1587 Start_Pos := Parse_Pos;
1588 Emit (C); -- First character is always emitted
1589
1590 -- Are we looking at an operator, or is this
1591 -- simply a normal character ?
1592
1593 elsif not Is_Mult (Parse_Pos) then
1594 Start_Pos := Parse_Pos;
1595 Case_Emit (C);
1596
1597 else
1598 -- We've got something like "abc?d". Mark this as a
1599 -- special case. What we want to emit is a first
1600 -- constant string for "ab", then one for "c" that will
1601 -- ultimately be transformed with a CURLY operator, A
1602 -- special case has to be handled for "a?", since there
1603 -- is no initial string to emit.
1604
1605 Has_Special_Operator := True;
1606 exit Parse_Loop;
1607 end if;
1608
1609 when '\' =>
1610 Start_Pos := Parse_Pos;
1611
1612 if Parse_Pos = Parse_End then
1613 Fail ("Trailing \");
1614
1615 else
1616 case Expression (Parse_Pos + 1) is
1617 when 'b' | 'B' | 's' | 'S' | 'd' | 'D'
1618 | 'w' | 'W' | '0' .. '9' | 'G' | 'A'
1619 => exit Parse_Loop;
1620 when 'n' => Emit (ASCII.LF);
1621 when 't' => Emit (ASCII.HT);
1622 when 'r' => Emit (ASCII.CR);
1623 when 'f' => Emit (ASCII.FF);
1624 when 'e' => Emit (ASCII.ESC);
1625 when 'a' => Emit (ASCII.BEL);
1626 when others => Emit (Expression (Parse_Pos + 1));
1627 end case;
1628
1629 Parse_Pos := Parse_Pos + 1;
1630 end if;
1631
1632 when others =>
1633 Start_Pos := Parse_Pos;
1634 Case_Emit (C);
1635 end case;
1636
1637 exit Parse_Loop when Emit_Ptr - Length_Ptr = 254;
1638
1639 Parse_Pos := Parse_Pos + 1;
1640
1641 exit Parse_Loop when Parse_Pos > Parse_End;
1642 end loop Parse_Loop;
1643
1644 -- Is the string followed by a '*+?{' operator ? If yes, and if there
1645 -- is an initial string to emit, do it now.
1646
1647 if Has_Special_Operator
1648 and then Emit_Ptr >= Length_Ptr + Next_Pointer_Bytes
1649 then
1650 Emit_Ptr := Emit_Ptr - 1;
1651 Parse_Pos := Start_Pos;
1652 end if;
1653
1654 if Length_Ptr <= PM.Size then
1655 Program (Length_Ptr) := Character'Val (Emit_Ptr - Length_Ptr - 2);
1656 end if;
1657
1658 Expr_Flags.Has_Width := True;
1659
1660 -- Slight optimization when there is a single character
1661
1662 if Emit_Ptr = Length_Ptr + 2 then
1663 Expr_Flags.Simple := True;
1664 end if;
1665 end Parse_Literal;
1666
1667 -----------------
1668 -- Parse_Piece --
1669 -----------------
1670
1671 -- Note that the branching code sequences used for '?' and the
1672 -- general cases of '*' and + are somewhat optimized: they use
1673 -- the same NOTHING node as both the endmarker for their branch
1674 -- list and the body of the last branch. It might seem that
1675 -- this node could be dispensed with entirely, but the endmarker
1676 -- role is not redundant.
1677
1678 procedure Parse_Piece
1679 (Expr_Flags : out Expression_Flags;
1680 IP : out Pointer)
1681 is
1682 Op : Character;
1683 New_Flags : Expression_Flags;
1684 Greedy : Boolean := True;
1685
1686 begin
1687 Parse_Atom (New_Flags, IP);
1688
1689 if IP = 0 then
1690 return;
1691 end if;
1692
1693 if Parse_Pos > Parse_End
1694 or else not Is_Mult (Parse_Pos)
1695 then
1696 Expr_Flags := New_Flags;
1697 return;
1698 end if;
1699
1700 Op := Expression (Parse_Pos);
1701
1702 Expr_Flags :=
1703 (if Op /= '+'
1704 then (SP_Start => True, others => False)
1705 else (Has_Width => True, others => False));
1706
1707 -- Detect non greedy operators in the easy cases
1708
1709 if Op /= '{'
1710 and then Parse_Pos + 1 <= Parse_End
1711 and then Expression (Parse_Pos + 1) = '?'
1712 then
1713 Greedy := False;
1714 Parse_Pos := Parse_Pos + 1;
1715 end if;
1716
1717 -- Generate the byte code
1718
1719 case Op is
1720 when '*' =>
1721
1722 if New_Flags.Simple then
1723 Insert_Operator (STAR, IP, Greedy);
1724 else
1725 Link_Tail (IP, Emit_Node (WHILEM));
1726 Insert_Curly_Operator
1727 (CURLYX, 0, Max_Curly_Repeat, IP, Greedy);
1728 Link_Tail (IP, Emit_Node (NOTHING));
1729 end if;
1730
1731 when '+' =>
1732
1733 if New_Flags.Simple then
1734 Insert_Operator (PLUS, IP, Greedy);
1735 else
1736 Link_Tail (IP, Emit_Node (WHILEM));
1737 Insert_Curly_Operator
1738 (CURLYX, 1, Max_Curly_Repeat, IP, Greedy);
1739 Link_Tail (IP, Emit_Node (NOTHING));
1740 end if;
1741
1742 when '?' =>
1743 if New_Flags.Simple then
1744 Insert_Curly_Operator (CURLY, 0, 1, IP, Greedy);
1745 else
1746 Link_Tail (IP, Emit_Node (WHILEM));
1747 Insert_Curly_Operator (CURLYX, 0, 1, IP, Greedy);
1748 Link_Tail (IP, Emit_Node (NOTHING));
1749 end if;
1750
1751 when '{' =>
1752 declare
1753 Min, Max : Natural;
1754
1755 begin
1756 Get_Curly_Arguments (Parse_Pos, Min, Max, Greedy);
1757
1758 if New_Flags.Simple then
1759 Insert_Curly_Operator (CURLY, Min, Max, IP, Greedy);
1760 else
1761 Link_Tail (IP, Emit_Node (WHILEM));
1762 Insert_Curly_Operator (CURLYX, Min, Max, IP, Greedy);
1763 Link_Tail (IP, Emit_Node (NOTHING));
1764 end if;
1765 end;
1766
1767 when others =>
1768 null;
1769 end case;
1770
1771 Parse_Pos := Parse_Pos + 1;
1772
1773 if Parse_Pos <= Parse_End
1774 and then Is_Mult (Parse_Pos)
1775 then
1776 Fail ("nested *+{");
1777 end if;
1778 end Parse_Piece;
1779
1780 ---------------------------------
1781 -- Parse_Posix_Character_Class --
1782 ---------------------------------
1783
1784 function Parse_Posix_Character_Class return Std_Class is
1785 Invert : Boolean := False;
1786 Class : Std_Class := ANYOF_NONE;
1787 E : String renames Expression;
1788
1789 -- Class names. Note that code assumes that the length of all
1790 -- classes starting with the same letter have the same length.
1791
1792 Alnum : constant String := "alnum:]";
1793 Alpha : constant String := "alpha:]";
1794 Ascii_C : constant String := "ascii:]";
1795 Cntrl : constant String := "cntrl:]";
1796 Digit : constant String := "digit:]";
1797 Graph : constant String := "graph:]";
1798 Lower : constant String := "lower:]";
1799 Print : constant String := "print:]";
1800 Punct : constant String := "punct:]";
1801 Space : constant String := "space:]";
1802 Upper : constant String := "upper:]";
1803 Word : constant String := "word:]";
1804 Xdigit : constant String := "xdigit:]";
1805
1806 begin
1807 -- Case of character class specified
1808
1809 if Parse_Pos <= Parse_End
1810 and then Expression (Parse_Pos) = ':'
1811 then
1812 Parse_Pos := Parse_Pos + 1;
1813
1814 -- Do we have something like: [[:^alpha:]]
1815
1816 if Parse_Pos <= Parse_End
1817 and then Expression (Parse_Pos) = '^'
1818 then
1819 Invert := True;
1820 Parse_Pos := Parse_Pos + 1;
1821 end if;
1822
1823 -- Check for class names based on first letter
1824
1825 case Expression (Parse_Pos) is
1826 when 'a' =>
1827
1828 -- All 'a' classes have the same length (Alnum'Length)
1829
1830 if Parse_Pos + Alnum'Length - 1 <= Parse_End then
1831 if
1832 E (Parse_Pos .. Parse_Pos + Alnum'Length - 1) = Alnum
1833 then
1834 Class :=
1835 (if Invert then ANYOF_NALNUMC else ANYOF_ALNUMC);
1836 Parse_Pos := Parse_Pos + Alnum'Length;
1837
1838 elsif
1839 E (Parse_Pos .. Parse_Pos + Alpha'Length - 1) = Alpha
1840 then
1841 Class :=
1842 (if Invert then ANYOF_NALPHA else ANYOF_ALPHA);
1843 Parse_Pos := Parse_Pos + Alpha'Length;
1844
1845 elsif E (Parse_Pos .. Parse_Pos + Ascii_C'Length - 1) =
1846 Ascii_C
1847 then
1848 Class :=
1849 (if Invert then ANYOF_NASCII else ANYOF_ASCII);
1850 Parse_Pos := Parse_Pos + Ascii_C'Length;
1851 else
1852 Fail ("Invalid character class: " & E);
1853 end if;
1854
1855 else
1856 Fail ("Invalid character class: " & E);
1857 end if;
1858
1859 when 'c' =>
1860 if Parse_Pos + Cntrl'Length - 1 <= Parse_End
1861 and then
1862 E (Parse_Pos .. Parse_Pos + Cntrl'Length - 1) = Cntrl
1863 then
1864 Class := (if Invert then ANYOF_NCNTRL else ANYOF_CNTRL);
1865 Parse_Pos := Parse_Pos + Cntrl'Length;
1866 else
1867 Fail ("Invalid character class: " & E);
1868 end if;
1869
1870 when 'd' =>
1871 if Parse_Pos + Digit'Length - 1 <= Parse_End
1872 and then
1873 E (Parse_Pos .. Parse_Pos + Digit'Length - 1) = Digit
1874 then
1875 Class := (if Invert then ANYOF_NDIGIT else ANYOF_DIGIT);
1876 Parse_Pos := Parse_Pos + Digit'Length;
1877 end if;
1878
1879 when 'g' =>
1880 if Parse_Pos + Graph'Length - 1 <= Parse_End
1881 and then
1882 E (Parse_Pos .. Parse_Pos + Graph'Length - 1) = Graph
1883 then
1884 Class := (if Invert then ANYOF_NGRAPH else ANYOF_GRAPH);
1885 Parse_Pos := Parse_Pos + Graph'Length;
1886 else
1887 Fail ("Invalid character class: " & E);
1888 end if;
1889
1890 when 'l' =>
1891 if Parse_Pos + Lower'Length - 1 <= Parse_End
1892 and then
1893 E (Parse_Pos .. Parse_Pos + Lower'Length - 1) = Lower
1894 then
1895 Class := (if Invert then ANYOF_NLOWER else ANYOF_LOWER);
1896 Parse_Pos := Parse_Pos + Lower'Length;
1897 else
1898 Fail ("Invalid character class: " & E);
1899 end if;
1900
1901 when 'p' =>
1902
1903 -- All 'p' classes have the same length
1904
1905 if Parse_Pos + Print'Length - 1 <= Parse_End then
1906 if
1907 E (Parse_Pos .. Parse_Pos + Print'Length - 1) = Print
1908 then
1909 Class :=
1910 (if Invert then ANYOF_NPRINT else ANYOF_PRINT);
1911 Parse_Pos := Parse_Pos + Print'Length;
1912
1913 elsif
1914 E (Parse_Pos .. Parse_Pos + Punct'Length - 1) = Punct
1915 then
1916 Class :=
1917 (if Invert then ANYOF_NPUNCT else ANYOF_PUNCT);
1918 Parse_Pos := Parse_Pos + Punct'Length;
1919
1920 else
1921 Fail ("Invalid character class: " & E);
1922 end if;
1923
1924 else
1925 Fail ("Invalid character class: " & E);
1926 end if;
1927
1928 when 's' =>
1929 if Parse_Pos + Space'Length - 1 <= Parse_End
1930 and then
1931 E (Parse_Pos .. Parse_Pos + Space'Length - 1) = Space
1932 then
1933 Class := (if Invert then ANYOF_NSPACE else ANYOF_SPACE);
1934 Parse_Pos := Parse_Pos + Space'Length;
1935 else
1936 Fail ("Invalid character class: " & E);
1937 end if;
1938
1939 when 'u' =>
1940 if Parse_Pos + Upper'Length - 1 <= Parse_End
1941 and then
1942 E (Parse_Pos .. Parse_Pos + Upper'Length - 1) = Upper
1943 then
1944 Class := (if Invert then ANYOF_NUPPER else ANYOF_UPPER);
1945 Parse_Pos := Parse_Pos + Upper'Length;
1946 else
1947 Fail ("Invalid character class: " & E);
1948 end if;
1949
1950 when 'w' =>
1951 if Parse_Pos + Word'Length - 1 <= Parse_End
1952 and then
1953 E (Parse_Pos .. Parse_Pos + Word'Length - 1) = Word
1954 then
1955 Class := (if Invert then ANYOF_NALNUM else ANYOF_ALNUM);
1956 Parse_Pos := Parse_Pos + Word'Length;
1957 else
1958 Fail ("Invalid character class: " & E);
1959 end if;
1960
1961 when 'x' =>
1962 if Parse_Pos + Xdigit'Length - 1 <= Parse_End
1963 and then
1964 E (Parse_Pos .. Parse_Pos + Xdigit'Length - 1) = Xdigit
1965 then
1966 Class := (if Invert then ANYOF_NXDIGIT else ANYOF_XDIGIT);
1967 Parse_Pos := Parse_Pos + Xdigit'Length;
1968
1969 else
1970 Fail ("Invalid character class: " & E);
1971 end if;
1972
1973 when others =>
1974 Fail ("Invalid character class: " & E);
1975 end case;
1976
1977 -- Character class not specified
1978
1979 else
1980 return ANYOF_NONE;
1981 end if;
1982
1983 return Class;
1984 end Parse_Posix_Character_Class;
1985
1986 -- Local Declarations
1987
1988 Result : Pointer;
1989
1990 Expr_Flags : Expression_Flags;
1991 pragma Unreferenced (Expr_Flags);
1992
1993 -- Start of processing for Compile
1994
1995 begin
1996 Parse (False, False, Expr_Flags, Result);
1997
1998 if Result = 0 then
1999 Fail ("Couldn't compile expression");
2000 end if;
2001
2002 Final_Code_Size := Emit_Ptr - 1;
2003
2004 -- Do we want to actually compile the expression, or simply get the
2005 -- code size ???
2006
2007 if Emit_Ptr <= PM.Size then
2008 Optimize (PM);
2009 end if;
2010
2011 PM.Flags := Flags;
2012 end Compile;
2013
2014 function Compile
2015 (Expression : String;
2016 Flags : Regexp_Flags := No_Flags) return Pattern_Matcher
2017 is
2018 -- Assume the compiled regexp will fit in 1000 chars. If it does not we
2019 -- will have to compile a second time once the correct size is known. If
2020 -- it fits, we save a significant amount of time by avoiding the second
2021 -- compilation.
2022
2023 Dummy : Pattern_Matcher (1000);
2024 Size : Program_Size;
2025
2026 begin
2027 Compile (Dummy, Expression, Size, Flags);
2028
2029 if Size <= Dummy.Size then
2030 return Pattern_Matcher'
2031 (Size => Size,
2032 First => Dummy.First,
2033 Anchored => Dummy.Anchored,
2034 Must_Have => Dummy.Must_Have,
2035 Must_Have_Length => Dummy.Must_Have_Length,
2036 Paren_Count => Dummy.Paren_Count,
2037 Flags => Dummy.Flags,
2038 Program =>
2039 Dummy.Program
2040 (Dummy.Program'First .. Dummy.Program'First + Size - 1));
2041 else
2042 -- We have to recompile now that we know the size
2043 -- ??? Can we use Ada 2005's return construct ?
2044
2045 declare
2046 Result : Pattern_Matcher (Size);
2047 begin
2048 Compile (Result, Expression, Size, Flags);
2049 return Result;
2050 end;
2051 end if;
2052 end Compile;
2053
2054 procedure Compile
2055 (Matcher : out Pattern_Matcher;
2056 Expression : String;
2057 Flags : Regexp_Flags := No_Flags)
2058 is
2059 Size : Program_Size;
2060
2061 begin
2062 Compile (Matcher, Expression, Size, Flags);
2063
2064 if Size > Matcher.Size then
2065 raise Expression_Error with "Pattern_Matcher is too small";
2066 end if;
2067 end Compile;
2068
2069 --------------------
2070 -- Dump_Operation --
2071 --------------------
2072
2073 procedure Dump_Operation
2074 (Program : Program_Data;
2075 Index : Pointer;
2076 Indent : Natural)
2077 is
2078 Current : Pointer := Index;
2079 begin
2080 Dump_Until (Program, Current, Current + 1, Indent);
2081 end Dump_Operation;
2082
2083 ----------------
2084 -- Dump_Until --
2085 ----------------
2086
2087 procedure Dump_Until
2088 (Program : Program_Data;
2089 Index : in out Pointer;
2090 Till : Pointer;
2091 Indent : Natural;
2092 Do_Print : Boolean := True)
2093 is
2094 function Image (S : String) return String;
2095 -- Remove leading space
2096
2097 -----------
2098 -- Image --
2099 -----------
2100
2101 function Image (S : String) return String is
2102 begin
2103 if S (S'First) = ' ' then
2104 return S (S'First + 1 .. S'Last);
2105 else
2106 return S;
2107 end if;
2108 end Image;
2109
2110 -- Local variables
2111
2112 Op : Opcode;
2113 Next : Pointer;
2114 Length : Pointer;
2115 Local_Indent : Natural := Indent;
2116
2117 -- Start of processing for Dump_Until
2118
2119 begin
2120 while Index < Till loop
2121 Op := Opcode'Val (Character'Pos ((Program (Index))));
2122 Next := Get_Next (Program, Index);
2123
2124 if Do_Print then
2125 declare
2126 Point : constant String := Pointer'Image (Index);
2127 begin
2128 Put ((1 .. 4 - Point'Length => ' ')
2129 & Point & ":"
2130 & (1 .. Local_Indent * 2 => ' ') & Opcode'Image (Op));
2131 end;
2132
2133 -- Print the parenthesis number
2134
2135 if Op = OPEN or else Op = CLOSE or else Op = REFF then
2136 Put (Image (Natural'Image
2137 (Character'Pos
2138 (Program (Index + Next_Pointer_Bytes)))));
2139 end if;
2140
2141 if Next = Index then
2142 Put (" (-)");
2143 else
2144 Put (" (" & Image (Pointer'Image (Next)) & ")");
2145 end if;
2146 end if;
2147
2148 case Op is
2149 when ANYOF =>
2150 declare
2151 Bitmap : Character_Class;
2152 Last : Character := ASCII.NUL;
2153 Current : Natural := 0;
2154 Current_Char : Character;
2155
2156 begin
2157 Bitmap_Operand (Program, Index, Bitmap);
2158
2159 if Do_Print then
2160 Put ("[");
2161
2162 while Current <= 255 loop
2163 Current_Char := Character'Val (Current);
2164
2165 -- First item in a range
2166
2167 if Get_From_Class (Bitmap, Current_Char) then
2168 Last := Current_Char;
2169
2170 -- Search for the last item in the range
2171
2172 loop
2173 Current := Current + 1;
2174 exit when Current > 255;
2175 Current_Char := Character'Val (Current);
2176 exit when
2177 not Get_From_Class (Bitmap, Current_Char);
2178 end loop;
2179
2180 if not Is_Graphic (Last) then
2181 Put (Last'Img);
2182 else
2183 Put (Last);
2184 end if;
2185
2186 if Character'Succ (Last) /= Current_Char then
2187 Put ("\-" & Character'Pred (Current_Char));
2188 end if;
2189
2190 else
2191 Current := Current + 1;
2192 end if;
2193 end loop;
2194
2195 Put_Line ("]");
2196 end if;
2197
2198 Index := Index + Next_Pointer_Bytes + Bitmap'Length;
2199 end;
2200
2201 when EXACT | EXACTF =>
2202 Length := String_Length (Program, Index);
2203 if Do_Print then
2204 Put (" (" & Image (Program_Size'Image (Length + 1))
2205 & " chars) <"
2206 & String (Program (String_Operand (Index)
2207 .. String_Operand (Index)
2208 + Length)));
2209 Put_Line (">");
2210 end if;
2211
2212 Index := String_Operand (Index) + Length + 1;
2213
2214 -- Node operand
2215
2216 when BRANCH | STAR | PLUS =>
2217 if Do_Print then
2218 New_Line;
2219 end if;
2220
2221 Index := Index + Next_Pointer_Bytes;
2222 Dump_Until (Program, Index, Pointer'Min (Next, Till),
2223 Local_Indent + 1, Do_Print);
2224
2225 when CURLY | CURLYX =>
2226 if Do_Print then
2227 Put_Line
2228 (" {"
2229 & Image (Natural'Image
2230 (Read_Natural (Program, Index + Next_Pointer_Bytes)))
2231 & ","
2232 & Image (Natural'Image (Read_Natural (Program, Index + 5)))
2233 & "}");
2234 end if;
2235
2236 Index := Index + 7;
2237 Dump_Until (Program, Index, Pointer'Min (Next, Till),
2238 Local_Indent + 1, Do_Print);
2239
2240 when OPEN =>
2241 if Do_Print then
2242 New_Line;
2243 end if;
2244
2245 Index := Index + 4;
2246 Local_Indent := Local_Indent + 1;
2247
2248 when CLOSE | REFF =>
2249 if Do_Print then
2250 New_Line;
2251 end if;
2252
2253 Index := Index + 4;
2254
2255 if Op = CLOSE then
2256 Local_Indent := Local_Indent - 1;
2257 end if;
2258
2259 when others =>
2260 Index := Index + Next_Pointer_Bytes;
2261
2262 if Do_Print then
2263 New_Line;
2264 end if;
2265
2266 exit when Op = EOP;
2267 end case;
2268 end loop;
2269 end Dump_Until;
2270
2271 ----------
2272 -- Dump --
2273 ----------
2274
2275 procedure Dump (Self : Pattern_Matcher) is
2276 Program : Program_Data renames Self.Program;
2277 Index : Pointer := Program'First;
2278
2279 -- Start of processing for Dump
2280
2281 begin
2282 Put_Line ("Must start with (Self.First) = "
2283 & Character'Image (Self.First));
2284
2285 if (Self.Flags and Case_Insensitive) /= 0 then
2286 Put_Line (" Case_Insensitive mode");
2287 end if;
2288
2289 if (Self.Flags and Single_Line) /= 0 then
2290 Put_Line (" Single_Line mode");
2291 end if;
2292
2293 if (Self.Flags and Multiple_Lines) /= 0 then
2294 Put_Line (" Multiple_Lines mode");
2295 end if;
2296
2297 Dump_Until (Program, Index, Self.Program'Last + 1, 0);
2298 end Dump;
2299
2300 --------------------
2301 -- Get_From_Class --
2302 --------------------
2303
2304 function Get_From_Class
2305 (Bitmap : Character_Class;
2306 C : Character) return Boolean
2307 is
2308 Value : constant Class_Byte := Character'Pos (C);
2309 begin
2310 return
2311 (Bitmap (Value / 8) and Bit_Conversion (Value mod 8)) /= 0;
2312 end Get_From_Class;
2313
2314 --------------
2315 -- Get_Next --
2316 --------------
2317
2318 function Get_Next (Program : Program_Data; IP : Pointer) return Pointer is
2319 begin
2320 return IP + Pointer (Read_Natural (Program, IP + 1));
2321 end Get_Next;
2322
2323 --------------
2324 -- Is_Alnum --
2325 --------------
2326
2327 function Is_Alnum (C : Character) return Boolean is
2328 begin
2329 return Is_Alphanumeric (C) or else C = '_';
2330 end Is_Alnum;
2331
2332 ------------------
2333 -- Is_Printable --
2334 ------------------
2335
2336 function Is_Printable (C : Character) return Boolean is
2337 begin
2338 -- Printable if space or graphic character or other whitespace
2339 -- Other white space includes (HT/LF/VT/FF/CR = codes 9-13)
2340
2341 return C in Character'Val (32) .. Character'Val (126)
2342 or else C in ASCII.HT .. ASCII.CR;
2343 end Is_Printable;
2344
2345 --------------------
2346 -- Is_White_Space --
2347 --------------------
2348
2349 function Is_White_Space (C : Character) return Boolean is
2350 begin
2351 -- Note: HT = 9, LF = 10, VT = 11, FF = 12, CR = 13
2352
2353 return C = ' ' or else C in ASCII.HT .. ASCII.CR;
2354 end Is_White_Space;
2355
2356 -----------
2357 -- Match --
2358 -----------
2359
2360 procedure Match
2361 (Self : Pattern_Matcher;
2362 Data : String;
2363 Matches : out Match_Array;
2364 Data_First : Integer := -1;
2365 Data_Last : Positive := Positive'Last)
2366 is
2367 Program : Program_Data renames Self.Program; -- Shorter notation
2368
2369 First_In_Data : constant Integer := Integer'Max (Data_First, Data'First);
2370 Last_In_Data : constant Integer := Integer'Min (Data_Last, Data'Last);
2371
2372 -- Global work variables
2373
2374 Input_Pos : Natural; -- String-input pointer
2375 BOL_Pos : Natural; -- Beginning of input, for ^ check
2376 Matched : Boolean := False; -- Until proven True
2377
2378 Matches_Full : Match_Array (0 .. Natural'Max (Self.Paren_Count,
2379 Matches'Last));
2380 -- Stores the value of all the parenthesis pairs.
2381 -- We do not use directly Matches, so that we can also use back
2382 -- references (REFF) even if Matches is too small.
2383
2384 type Natural_Array is array (Match_Count range <>) of Natural;
2385 Matches_Tmp : Natural_Array (Matches_Full'Range);
2386 -- Save the opening position of parenthesis
2387
2388 Last_Paren : Natural := 0;
2389 -- Last parenthesis seen
2390
2391 Greedy : Boolean := True;
2392 -- True if the next operator should be greedy
2393
2394 type Current_Curly_Record;
2395 type Current_Curly_Access is access all Current_Curly_Record;
2396 type Current_Curly_Record is record
2397 Paren_Floor : Natural; -- How far back to strip parenthesis data
2398 Cur : Integer; -- How many instances of scan we've matched
2399 Min : Natural; -- Minimal number of scans to match
2400 Max : Natural; -- Maximal number of scans to match
2401 Greedy : Boolean; -- Whether to work our way up or down
2402 Scan : Pointer; -- The thing to match
2403 Next : Pointer; -- What has to match after it
2404 Lastloc : Natural; -- Where we started matching this scan
2405 Old_Cc : Current_Curly_Access; -- Before we started this one
2406 end record;
2407 -- Data used to handle the curly operator and the plus and star
2408 -- operators for complex expressions.
2409
2410 Current_Curly : Current_Curly_Access := null;
2411 -- The curly currently being processed
2412
2413 -----------------------
2414 -- Local Subprograms --
2415 -----------------------
2416
2417 function Index (Start : Positive; C : Character) return Natural;
2418 -- Find character C in Data starting at Start and return position
2419
2420 function Repeat
2421 (IP : Pointer;
2422 Max : Natural := Natural'Last) return Natural;
2423 -- Repeatedly match something simple, report how many
2424 -- It only matches on things of length 1.
2425 -- Starting from Input_Pos, it matches at most Max CURLY.
2426
2427 function Try (Pos : Positive) return Boolean;
2428 -- Try to match at specific point
2429
2430 function Match (IP : Pointer) return Boolean;
2431 -- This is the main matching routine. Conceptually the strategy
2432 -- is simple: check to see whether the current node matches,
2433 -- call self recursively to see whether the rest matches,
2434 -- and then act accordingly.
2435 --
2436 -- In practice Match makes some effort to avoid recursion, in
2437 -- particular by going through "ordinary" nodes (that don't
2438 -- need to know whether the rest of the match failed) by
2439 -- using a loop instead of recursion.
2440 -- Why is the above comment part of the spec rather than body ???
2441
2442 function Match_Whilem return Boolean;
2443 -- Return True if a WHILEM matches the Current_Curly
2444
2445 function Recurse_Match (IP : Pointer; From : Natural) return Boolean;
2446 pragma Inline (Recurse_Match);
2447 -- Calls Match recursively. It saves and restores the parenthesis
2448 -- status and location in the input stream correctly, so that
2449 -- backtracking is possible
2450
2451 function Match_Simple_Operator
2452 (Op : Opcode;
2453 Scan : Pointer;
2454 Next : Pointer;
2455 Greedy : Boolean) return Boolean;
2456 -- Return True it the simple operator (possibly non-greedy) matches
2457
2458 Dump_Indent : Integer := -1;
2459 procedure Dump_Current (Scan : Pointer; Prefix : Boolean := True);
2460 procedure Dump_Error (Msg : String);
2461 -- Debug: print the current context
2462
2463 pragma Inline (Index);
2464 pragma Inline (Repeat);
2465
2466 -- These are two complex functions, but used only once
2467
2468 pragma Inline (Match_Whilem);
2469 pragma Inline (Match_Simple_Operator);
2470
2471 -----------
2472 -- Index --
2473 -----------
2474
2475 function Index (Start : Positive; C : Character) return Natural is
2476 begin
2477 for J in Start .. Last_In_Data loop
2478 if Data (J) = C then
2479 return J;
2480 end if;
2481 end loop;
2482
2483 return 0;
2484 end Index;
2485
2486 -------------------
2487 -- Recurse_Match --
2488 -------------------
2489
2490 function Recurse_Match (IP : Pointer; From : Natural) return Boolean is
2491 L : constant Natural := Last_Paren;
2492 Tmp_F : constant Match_Array :=
2493 Matches_Full (From + 1 .. Matches_Full'Last);
2494 Start : constant Natural_Array :=
2495 Matches_Tmp (From + 1 .. Matches_Tmp'Last);
2496 Input : constant Natural := Input_Pos;
2497
2498 Dump_Indent_Save : constant Integer := Dump_Indent;
2499
2500 begin
2501 if Match (IP) then
2502 return True;
2503 end if;
2504
2505 Last_Paren := L;
2506 Matches_Full (Tmp_F'Range) := Tmp_F;
2507 Matches_Tmp (Start'Range) := Start;
2508 Input_Pos := Input;
2509 Dump_Indent := Dump_Indent_Save;
2510 return False;
2511 end Recurse_Match;
2512
2513 ------------------
2514 -- Dump_Current --
2515 ------------------
2516
2517 procedure Dump_Current (Scan : Pointer; Prefix : Boolean := True) is
2518 Length : constant := 10;
2519 Pos : constant String := Integer'Image (Input_Pos);
2520
2521 begin
2522 if Prefix then
2523 Put ((1 .. 5 - Pos'Length => ' '));
2524 Put (Pos & " <"
2525 & Data (Input_Pos
2526 .. Integer'Min (Last_In_Data, Input_Pos + Length - 1)));
2527 Put ((1 .. Length - 1 - Last_In_Data + Input_Pos => ' '));
2528 Put ("> |");
2529
2530 else
2531 Put (" ");
2532 end if;
2533
2534 Dump_Operation (Program, Scan, Indent => Dump_Indent);
2535 end Dump_Current;
2536
2537 ----------------
2538 -- Dump_Error --
2539 ----------------
2540
2541 procedure Dump_Error (Msg : String) is
2542 begin
2543 Put (" | ");
2544 Put ((1 .. Dump_Indent * 2 => ' '));
2545 Put_Line (Msg);
2546 end Dump_Error;
2547
2548 -----------
2549 -- Match --
2550 -----------
2551
2552 function Match (IP : Pointer) return Boolean is
2553 Scan : Pointer := IP;
2554 Next : Pointer;
2555 Op : Opcode;
2556 Result : Boolean;
2557
2558 begin
2559 Dump_Indent := Dump_Indent + 1;
2560
2561 State_Machine :
2562 loop
2563 pragma Assert (Scan /= 0);
2564
2565 -- Determine current opcode and count its usage in debug mode
2566
2567 Op := Opcode'Val (Character'Pos (Program (Scan)));
2568
2569 -- Calculate offset of next instruction. Second character is most
2570 -- significant in Program_Data.
2571
2572 Next := Get_Next (Program, Scan);
2573
2574 if Debug then
2575 Dump_Current (Scan);
2576 end if;
2577
2578 case Op is
2579 when EOP =>
2580 Dump_Indent := Dump_Indent - 1;
2581 return True; -- Success
2582
2583 when BRANCH =>
2584 if Program (Next) /= BRANCH then
2585 Next := Operand (Scan); -- No choice, avoid recursion
2586
2587 else
2588 loop
2589 if Recurse_Match (Operand (Scan), 0) then
2590 Dump_Indent := Dump_Indent - 1;
2591 return True;
2592 end if;
2593
2594 Scan := Get_Next (Program, Scan);
2595 exit when Scan = 0 or else Program (Scan) /= BRANCH;
2596 end loop;
2597
2598 exit State_Machine;
2599 end if;
2600
2601 when NOTHING =>
2602 null;
2603
2604 when BOL =>
2605 exit State_Machine when Input_Pos /= BOL_Pos
2606 and then ((Self.Flags and Multiple_Lines) = 0
2607 or else Data (Input_Pos - 1) /= ASCII.LF);
2608
2609 when MBOL =>
2610 exit State_Machine when Input_Pos /= BOL_Pos
2611 and then Data (Input_Pos - 1) /= ASCII.LF;
2612
2613 when SBOL =>
2614 exit State_Machine when Input_Pos /= BOL_Pos;
2615
2616 when EOL =>
2617
2618 -- A combination of MEOL and SEOL
2619
2620 if (Self.Flags and Multiple_Lines) = 0 then
2621
2622 -- Single line mode
2623
2624 exit State_Machine when Input_Pos <= Data'Last;
2625
2626 elsif Input_Pos <= Last_In_Data then
2627 exit State_Machine when Data (Input_Pos) /= ASCII.LF;
2628 else
2629 exit State_Machine when Last_In_Data /= Data'Last;
2630 end if;
2631
2632 when MEOL =>
2633 if Input_Pos <= Last_In_Data then
2634 exit State_Machine when Data (Input_Pos) /= ASCII.LF;
2635 else
2636 exit State_Machine when Last_In_Data /= Data'Last;
2637 end if;
2638
2639 when SEOL =>
2640
2641 -- If there is a character before Data'Last (even if
2642 -- Last_In_Data stops before then), we can't have the
2643 -- end of the line.
2644
2645 exit State_Machine when Input_Pos <= Data'Last;
2646
2647 when BOUND | NBOUND =>
2648
2649 -- Was last char in word ?
2650
2651 declare
2652 N : Boolean := False;
2653 Ln : Boolean := False;
2654
2655 begin
2656 if Input_Pos /= First_In_Data then
2657 N := Is_Alnum (Data (Input_Pos - 1));
2658 end if;
2659
2660 Ln :=
2661 (if Input_Pos > Last_In_Data
2662 then False
2663 else Is_Alnum (Data (Input_Pos)));
2664
2665 if Op = BOUND then
2666 if N = Ln then
2667 exit State_Machine;
2668 end if;
2669 else
2670 if N /= Ln then
2671 exit State_Machine;
2672 end if;
2673 end if;
2674 end;
2675
2676 when SPACE =>
2677 exit State_Machine when Input_Pos > Last_In_Data
2678 or else not Is_White_Space (Data (Input_Pos));
2679 Input_Pos := Input_Pos + 1;
2680
2681 when NSPACE =>
2682 exit State_Machine when Input_Pos > Last_In_Data
2683 or else Is_White_Space (Data (Input_Pos));
2684 Input_Pos := Input_Pos + 1;
2685
2686 when DIGIT =>
2687 exit State_Machine when Input_Pos > Last_In_Data
2688 or else not Is_Digit (Data (Input_Pos));
2689 Input_Pos := Input_Pos + 1;
2690
2691 when NDIGIT =>
2692 exit State_Machine when Input_Pos > Last_In_Data
2693 or else Is_Digit (Data (Input_Pos));
2694 Input_Pos := Input_Pos + 1;
2695
2696 when ALNUM =>
2697 exit State_Machine when Input_Pos > Last_In_Data
2698 or else not Is_Alnum (Data (Input_Pos));
2699 Input_Pos := Input_Pos + 1;
2700
2701 when NALNUM =>
2702 exit State_Machine when Input_Pos > Last_In_Data
2703 or else Is_Alnum (Data (Input_Pos));
2704 Input_Pos := Input_Pos + 1;
2705
2706 when ANY =>
2707 exit State_Machine when Input_Pos > Last_In_Data
2708 or else Data (Input_Pos) = ASCII.LF;
2709 Input_Pos := Input_Pos + 1;
2710
2711 when SANY =>
2712 exit State_Machine when Input_Pos > Last_In_Data;
2713 Input_Pos := Input_Pos + 1;
2714
2715 when EXACT =>
2716 declare
2717 Opnd : Pointer := String_Operand (Scan);
2718 Current : Positive := Input_Pos;
2719 Last : constant Pointer :=
2720 Opnd + String_Length (Program, Scan);
2721
2722 begin
2723 while Opnd <= Last loop
2724 exit State_Machine when Current > Last_In_Data
2725 or else Program (Opnd) /= Data (Current);
2726 Current := Current + 1;
2727 Opnd := Opnd + 1;
2728 end loop;
2729
2730 Input_Pos := Current;
2731 end;
2732
2733 when EXACTF =>
2734 declare
2735 Opnd : Pointer := String_Operand (Scan);
2736 Current : Positive := Input_Pos;
2737
2738 Last : constant Pointer :=
2739 Opnd + String_Length (Program, Scan);
2740
2741 begin
2742 while Opnd <= Last loop
2743 exit State_Machine when Current > Last_In_Data
2744 or else Program (Opnd) /= To_Lower (Data (Current));
2745 Current := Current + 1;
2746 Opnd := Opnd + 1;
2747 end loop;
2748
2749 Input_Pos := Current;
2750 end;
2751
2752 when ANYOF =>
2753 declare
2754 Bitmap : Character_Class;
2755 begin
2756 Bitmap_Operand (Program, Scan, Bitmap);
2757 exit State_Machine when Input_Pos > Last_In_Data
2758 or else not Get_From_Class (Bitmap, Data (Input_Pos));
2759 Input_Pos := Input_Pos + 1;
2760 end;
2761
2762 when OPEN =>
2763 declare
2764 No : constant Natural :=
2765 Character'Pos (Program (Operand (Scan)));
2766 begin
2767 Matches_Tmp (No) := Input_Pos;
2768 end;
2769
2770 when CLOSE =>
2771 declare
2772 No : constant Natural :=
2773 Character'Pos (Program (Operand (Scan)));
2774
2775 begin
2776 Matches_Full (No) := (Matches_Tmp (No), Input_Pos - 1);
2777
2778 if Last_Paren < No then
2779 Last_Paren := No;
2780 end if;
2781 end;
2782
2783 when REFF =>
2784 declare
2785 No : constant Natural :=
2786 Character'Pos (Program (Operand (Scan)));
2787
2788 Data_Pos : Natural;
2789
2790 begin
2791 -- If we haven't seen that parenthesis yet
2792
2793 if Last_Paren < No then
2794 Dump_Indent := Dump_Indent - 1;
2795
2796 if Debug then
2797 Dump_Error ("REFF: No match, backtracking");
2798 end if;
2799
2800 return False;
2801 end if;
2802
2803 Data_Pos := Matches_Full (No).First;
2804
2805 while Data_Pos <= Matches_Full (No).Last loop
2806 if Input_Pos > Last_In_Data
2807 or else Data (Input_Pos) /= Data (Data_Pos)
2808 then
2809 Dump_Indent := Dump_Indent - 1;
2810
2811 if Debug then
2812 Dump_Error ("REFF: No match, backtracking");
2813 end if;
2814
2815 return False;
2816 end if;
2817
2818 Input_Pos := Input_Pos + 1;
2819 Data_Pos := Data_Pos + 1;
2820 end loop;
2821 end;
2822
2823 when MINMOD =>
2824 Greedy := False;
2825
2826 when STAR | PLUS | CURLY =>
2827 declare
2828 Greed : constant Boolean := Greedy;
2829 begin
2830 Greedy := True;
2831 Result := Match_Simple_Operator (Op, Scan, Next, Greed);
2832 Dump_Indent := Dump_Indent - 1;
2833 return Result;
2834 end;
2835
2836 when CURLYX =>
2837
2838 -- Looking at something like:
2839
2840 -- 1: CURLYX {n,m} (->4)
2841 -- 2: code for complex thing (->3)
2842 -- 3: WHILEM (->0)
2843 -- 4: NOTHING
2844
2845 declare
2846 Min : constant Natural :=
2847 Read_Natural (Program, Scan + Next_Pointer_Bytes);
2848 Max : constant Natural :=
2849 Read_Natural
2850 (Program, Scan + Next_Pointer_Bytes + 2);
2851 Cc : aliased Current_Curly_Record;
2852
2853 Has_Match : Boolean;
2854
2855 begin
2856 Cc := (Paren_Floor => Last_Paren,
2857 Cur => -1,
2858 Min => Min,
2859 Max => Max,
2860 Greedy => Greedy,
2861 Scan => Scan + 7,
2862 Next => Next,
2863 Lastloc => 0,
2864 Old_Cc => Current_Curly);
2865 Greedy := True;
2866 Current_Curly := Cc'Unchecked_Access;
2867
2868 Has_Match := Match (Next - Next_Pointer_Bytes);
2869
2870 -- Start on the WHILEM
2871
2872 Current_Curly := Cc.Old_Cc;
2873 Dump_Indent := Dump_Indent - 1;
2874
2875 if not Has_Match then
2876 if Debug then
2877 Dump_Error ("CURLYX failed...");
2878 end if;
2879 end if;
2880
2881 return Has_Match;
2882 end;
2883
2884 when WHILEM =>
2885 Result := Match_Whilem;
2886 Dump_Indent := Dump_Indent - 1;
2887
2888 if Debug and then not Result then
2889 Dump_Error ("WHILEM: no match, backtracking");
2890 end if;
2891
2892 return Result;
2893 end case;
2894
2895 Scan := Next;
2896 end loop State_Machine;
2897
2898 if Debug then
2899 Dump_Error ("failed...");
2900 Dump_Indent := Dump_Indent - 1;
2901 end if;
2902
2903 -- If we get here, there is no match. For successful matches when EOP
2904 -- is the terminating point.
2905
2906 return False;
2907 end Match;
2908
2909 ---------------------------
2910 -- Match_Simple_Operator --
2911 ---------------------------
2912
2913 function Match_Simple_Operator
2914 (Op : Opcode;
2915 Scan : Pointer;
2916 Next : Pointer;
2917 Greedy : Boolean) return Boolean
2918 is
2919 Next_Char : Character := ASCII.NUL;
2920 Next_Char_Known : Boolean := False;
2921 No : Integer; -- Can be negative
2922 Min : Natural;
2923 Max : Natural := Natural'Last;
2924 Operand_Code : Pointer;
2925 Old : Natural;
2926 Last_Pos : Natural;
2927 Save : constant Natural := Input_Pos;
2928
2929 begin
2930 -- Lookahead to avoid useless match attempts when we know what
2931 -- character comes next.
2932
2933 if Program (Next) = EXACT then
2934 Next_Char := Program (String_Operand (Next));
2935 Next_Char_Known := True;
2936 end if;
2937
2938 -- Find the minimal and maximal values for the operator
2939
2940 case Op is
2941 when STAR =>
2942 Min := 0;
2943 Operand_Code := Operand (Scan);
2944
2945 when PLUS =>
2946 Min := 1;
2947 Operand_Code := Operand (Scan);
2948
2949 when others =>
2950 Min := Read_Natural (Program, Scan + Next_Pointer_Bytes);
2951 Max := Read_Natural (Program, Scan + Next_Pointer_Bytes + 2);
2952 Operand_Code := Scan + 7;
2953 end case;
2954
2955 if Debug then
2956 Dump_Current (Operand_Code, Prefix => False);
2957 end if;
2958
2959 -- Non greedy operators
2960
2961 if not Greedy then
2962
2963 -- Test we can repeat at least Min times
2964
2965 if Min /= 0 then
2966 No := Repeat (Operand_Code, Min);
2967
2968 if No < Min then
2969 if Debug then
2970 Dump_Error ("failed... matched" & No'Img & " times");
2971 end if;
2972
2973 return False;
2974 end if;
2975 end if;
2976
2977 Old := Input_Pos;
2978
2979 -- Find the place where 'next' could work
2980
2981 if Next_Char_Known then
2982
2983 -- Last position to check
2984
2985 if Max = Natural'Last then
2986 Last_Pos := Last_In_Data;
2987 else
2988 Last_Pos := Input_Pos + Max;
2989
2990 if Last_Pos > Last_In_Data then
2991 Last_Pos := Last_In_Data;
2992 end if;
2993 end if;
2994
2995 -- Look for the first possible opportunity
2996
2997 if Debug then
2998 Dump_Error ("Next_Char must be " & Next_Char);
2999 end if;
3000
3001 loop
3002 -- Find the next possible position
3003
3004 while Input_Pos <= Last_Pos
3005 and then Data (Input_Pos) /= Next_Char
3006 loop
3007 Input_Pos := Input_Pos + 1;
3008 end loop;
3009
3010 if Input_Pos > Last_Pos then
3011 return False;
3012 end if;
3013
3014 -- Check that we still match if we stop at the position we
3015 -- just found.
3016
3017 declare
3018 Num : constant Natural := Input_Pos - Old;
3019
3020 begin
3021 Input_Pos := Old;
3022
3023 if Debug then
3024 Dump_Error ("Would we still match at that position?");
3025 end if;
3026
3027 if Repeat (Operand_Code, Num) < Num then
3028 return False;
3029 end if;
3030 end;
3031
3032 -- Input_Pos now points to the new position
3033
3034 if Match (Get_Next (Program, Scan)) then
3035 return True;
3036 end if;
3037
3038 Old := Input_Pos;
3039 Input_Pos := Input_Pos + 1;
3040 end loop;
3041
3042 -- We do not know what the next character is
3043
3044 else
3045 while Max >= Min loop
3046 if Debug then
3047 Dump_Error ("Non-greedy repeat, N=" & Min'Img);
3048 Dump_Error ("Do we still match Next if we stop here?");
3049 end if;
3050
3051 -- If the next character matches
3052
3053 if Recurse_Match (Next, 1) then
3054 return True;
3055 end if;
3056
3057 Input_Pos := Save + Min;
3058
3059 -- Could not or did not match -- move forward
3060
3061 if Repeat (Operand_Code, 1) /= 0 then
3062 Min := Min + 1;
3063 else
3064 if Debug then
3065 Dump_Error ("Non-greedy repeat failed...");
3066 end if;
3067
3068 return False;
3069 end if;
3070 end loop;
3071 end if;
3072
3073 return False;
3074
3075 -- Greedy operators
3076
3077 else
3078 No := Repeat (Operand_Code, Max);
3079
3080 if Debug and then No < Min then
3081 Dump_Error ("failed... matched" & No'Img & " times");
3082 end if;
3083
3084 -- ??? Perl has some special code here in case the next
3085 -- instruction is of type EOL, since $ and \Z can match before
3086 -- *and* after newline at the end.
3087
3088 -- ??? Perl has some special code here in case (paren) is True
3089
3090 -- Else, if we don't have any parenthesis
3091
3092 while No >= Min loop
3093 if not Next_Char_Known
3094 or else (Input_Pos <= Last_In_Data
3095 and then Data (Input_Pos) = Next_Char)
3096 then
3097 if Match (Next) then
3098 return True;
3099 end if;
3100 end if;
3101
3102 -- Could not or did not work, we back up
3103
3104 No := No - 1;
3105 Input_Pos := Save + No;
3106 end loop;
3107
3108 return False;
3109 end if;
3110 end Match_Simple_Operator;
3111
3112 ------------------
3113 -- Match_Whilem --
3114 ------------------
3115
3116 -- This is really hard to understand, because after we match what we
3117 -- are trying to match, we must make sure the rest of the REx is going
3118 -- to match for sure, and to do that we have to go back UP the parse
3119 -- tree by recursing ever deeper. And if it fails, we have to reset
3120 -- our parent's current state that we can try again after backing off.
3121
3122 function Match_Whilem return Boolean is
3123 Cc : constant Current_Curly_Access := Current_Curly;
3124
3125 N : constant Natural := Cc.Cur + 1;
3126 Ln : Natural := 0;
3127
3128 Lastloc : constant Natural := Cc.Lastloc;
3129 -- Detection of 0-len
3130
3131 begin
3132 -- If degenerate scan matches "", assume scan done
3133
3134 if Input_Pos = Cc.Lastloc
3135 and then N >= Cc.Min
3136 then
3137 -- Temporarily restore the old context, and check that we
3138 -- match was comes after CURLYX.
3139
3140 Current_Curly := Cc.Old_Cc;
3141
3142 if Current_Curly /= null then
3143 Ln := Current_Curly.Cur;
3144 end if;
3145
3146 if Match (Cc.Next) then
3147 return True;
3148 end if;
3149
3150 if Current_Curly /= null then
3151 Current_Curly.Cur := Ln;
3152 end if;
3153
3154 Current_Curly := Cc;
3155 return False;
3156 end if;
3157
3158 -- First, just match a string of min scans
3159
3160 if N < Cc.Min then
3161 Cc.Cur := N;
3162 Cc.Lastloc := Input_Pos;
3163
3164 if Debug then
3165 Dump_Error
3166 ("Tests that we match at least" & Cc.Min'Img & " N=" & N'Img);
3167 end if;
3168
3169 if Match (Cc.Scan) then
3170 return True;
3171 end if;
3172
3173 Cc.Cur := N - 1;
3174 Cc.Lastloc := Lastloc;
3175
3176 if Debug then
3177 Dump_Error ("failed...");
3178 end if;
3179
3180 return False;
3181 end if;
3182
3183 -- Prefer next over scan for minimal matching
3184
3185 if not Cc.Greedy then
3186 Current_Curly := Cc.Old_Cc;
3187
3188 if Current_Curly /= null then
3189 Ln := Current_Curly.Cur;
3190 end if;
3191
3192 if Recurse_Match (Cc.Next, Cc.Paren_Floor) then
3193 return True;
3194 end if;
3195
3196 if Current_Curly /= null then
3197 Current_Curly.Cur := Ln;
3198 end if;
3199
3200 Current_Curly := Cc;
3201
3202 -- Maximum greed exceeded ?
3203
3204 if N >= Cc.Max then
3205 if Debug then
3206 Dump_Error ("failed...");
3207 end if;
3208 return False;
3209 end if;
3210
3211 -- Try scanning more and see if it helps
3212 Cc.Cur := N;
3213 Cc.Lastloc := Input_Pos;
3214
3215 if Debug then
3216 Dump_Error ("Next failed, what about Current?");
3217 end if;
3218
3219 if Recurse_Match (Cc.Scan, Cc.Paren_Floor) then
3220 return True;
3221 end if;
3222
3223 Cc.Cur := N - 1;
3224 Cc.Lastloc := Lastloc;
3225 return False;
3226 end if;
3227
3228 -- Prefer scan over next for maximal matching
3229
3230 if N < Cc.Max then -- more greed allowed ?
3231 Cc.Cur := N;
3232 Cc.Lastloc := Input_Pos;
3233
3234 if Debug then
3235 Dump_Error ("Recurse at current position");
3236 end if;
3237
3238 if Recurse_Match (Cc.Scan, Cc.Paren_Floor) then
3239 return True;
3240 end if;
3241 end if;
3242
3243 -- Failed deeper matches of scan, so see if this one works
3244
3245 Current_Curly := Cc.Old_Cc;
3246
3247 if Current_Curly /= null then
3248 Ln := Current_Curly.Cur;
3249 end if;
3250
3251 if Debug then
3252 Dump_Error ("Failed matching for later positions");
3253 end if;
3254
3255 if Match (Cc.Next) then
3256 return True;
3257 end if;
3258
3259 if Current_Curly /= null then
3260 Current_Curly.Cur := Ln;
3261 end if;
3262
3263 Current_Curly := Cc;
3264 Cc.Cur := N - 1;
3265 Cc.Lastloc := Lastloc;
3266
3267 if Debug then
3268 Dump_Error ("failed...");
3269 end if;
3270
3271 return False;
3272 end Match_Whilem;
3273
3274 ------------
3275 -- Repeat --
3276 ------------
3277
3278 function Repeat
3279 (IP : Pointer;
3280 Max : Natural := Natural'Last) return Natural
3281 is
3282 Scan : Natural := Input_Pos;
3283 Last : Natural;
3284 Op : constant Opcode := Opcode'Val (Character'Pos (Program (IP)));
3285 Count : Natural;
3286 C : Character;
3287 Is_First : Boolean := True;
3288 Bitmap : Character_Class;
3289
3290 begin
3291 if Max = Natural'Last or else Scan + Max - 1 > Last_In_Data then
3292 Last := Last_In_Data;
3293 else
3294 Last := Scan + Max - 1;
3295 end if;
3296
3297 case Op is
3298 when ANY =>
3299 while Scan <= Last
3300 and then Data (Scan) /= ASCII.LF
3301 loop
3302 Scan := Scan + 1;
3303 end loop;
3304
3305 when SANY =>
3306 Scan := Last + 1;
3307
3308 when EXACT =>
3309
3310 -- The string has only one character if Repeat was called
3311
3312 C := Program (String_Operand (IP));
3313 while Scan <= Last
3314 and then C = Data (Scan)
3315 loop
3316 Scan := Scan + 1;
3317 end loop;
3318
3319 when EXACTF =>
3320
3321 -- The string has only one character if Repeat was called
3322
3323 C := Program (String_Operand (IP));
3324 while Scan <= Last
3325 and then To_Lower (C) = Data (Scan)
3326 loop
3327 Scan := Scan + 1;
3328 end loop;
3329
3330 when ANYOF =>
3331 if Is_First then
3332 Bitmap_Operand (Program, IP, Bitmap);
3333 Is_First := False;
3334 end if;
3335
3336 while Scan <= Last
3337 and then Get_From_Class (Bitmap, Data (Scan))
3338 loop
3339 Scan := Scan + 1;
3340 end loop;
3341
3342 when ALNUM =>
3343 while Scan <= Last
3344 and then Is_Alnum (Data (Scan))
3345 loop
3346 Scan := Scan + 1;
3347 end loop;
3348
3349 when NALNUM =>
3350 while Scan <= Last
3351 and then not Is_Alnum (Data (Scan))
3352 loop
3353 Scan := Scan + 1;
3354 end loop;
3355
3356 when SPACE =>
3357 while Scan <= Last
3358 and then Is_White_Space (Data (Scan))
3359 loop
3360 Scan := Scan + 1;
3361 end loop;
3362
3363 when NSPACE =>
3364 while Scan <= Last
3365 and then not Is_White_Space (Data (Scan))
3366 loop
3367 Scan := Scan + 1;
3368 end loop;
3369
3370 when DIGIT =>
3371 while Scan <= Last
3372 and then Is_Digit (Data (Scan))
3373 loop
3374 Scan := Scan + 1;
3375 end loop;
3376
3377 when NDIGIT =>
3378 while Scan <= Last
3379 and then not Is_Digit (Data (Scan))
3380 loop
3381 Scan := Scan + 1;
3382 end loop;
3383
3384 when others =>
3385 raise Program_Error;
3386 end case;
3387
3388 Count := Scan - Input_Pos;
3389 Input_Pos := Scan;
3390 return Count;
3391 end Repeat;
3392
3393 ---------
3394 -- Try --
3395 ---------
3396
3397 function Try (Pos : Positive) return Boolean is
3398 begin
3399 Input_Pos := Pos;
3400 Last_Paren := 0;
3401 Matches_Full := (others => No_Match);
3402
3403 if Match (Program_First) then
3404 Matches_Full (0) := (Pos, Input_Pos - 1);
3405 return True;
3406 end if;
3407
3408 return False;
3409 end Try;
3410
3411 -- Start of processing for Match
3412
3413 begin
3414 -- Do we have the regexp Never_Match?
3415
3416 if Self.Size = 0 then
3417 Matches := (others => No_Match);
3418 return;
3419 end if;
3420
3421 -- If there is a "must appear" string, look for it
3422
3423 if Self.Must_Have_Length > 0 then
3424 declare
3425 First : constant Character := Program (Self.Must_Have);
3426 Must_First : constant Pointer := Self.Must_Have;
3427 Must_Last : constant Pointer :=
3428 Must_First + Pointer (Self.Must_Have_Length - 1);
3429 Next_Try : Natural := Index (First_In_Data, First);
3430
3431 begin
3432 while Next_Try /= 0
3433 and then Data (Next_Try .. Next_Try + Self.Must_Have_Length - 1)
3434 = String (Program (Must_First .. Must_Last))
3435 loop
3436 Next_Try := Index (Next_Try + 1, First);
3437 end loop;
3438
3439 if Next_Try = 0 then
3440 Matches := (others => No_Match);
3441 return; -- Not present
3442 end if;
3443 end;
3444 end if;
3445
3446 -- Mark beginning of line for ^
3447
3448 BOL_Pos := Data'First;
3449
3450 -- Simplest case first: an anchored match need be tried only once
3451
3452 if Self.Anchored and then (Self.Flags and Multiple_Lines) = 0 then
3453 Matched := Try (First_In_Data);
3454
3455 elsif Self.Anchored then
3456 declare
3457 Next_Try : Natural := First_In_Data;
3458 begin
3459 -- Test the first position in the buffer
3460 Matched := Try (Next_Try);
3461
3462 -- Else only test after newlines
3463
3464 if not Matched then
3465 while Next_Try <= Last_In_Data loop
3466 while Next_Try <= Last_In_Data
3467 and then Data (Next_Try) /= ASCII.LF
3468 loop
3469 Next_Try := Next_Try + 1;
3470 end loop;
3471
3472 Next_Try := Next_Try + 1;
3473
3474 if Next_Try <= Last_In_Data then
3475 Matched := Try (Next_Try);
3476 exit when Matched;
3477 end if;
3478 end loop;
3479 end if;
3480 end;
3481
3482 elsif Self.First /= ASCII.NUL then
3483 -- We know what char it must start with
3484
3485 declare
3486 Next_Try : Natural := Index (First_In_Data, Self.First);
3487
3488 begin
3489 while Next_Try /= 0 loop
3490 Matched := Try (Next_Try);
3491 exit when Matched;
3492 Next_Try := Index (Next_Try + 1, Self.First);
3493 end loop;
3494 end;
3495
3496 else
3497 -- Messy cases: try all locations (including for the empty string)
3498
3499 Matched := Try (First_In_Data);
3500
3501 if not Matched then
3502 for S in First_In_Data + 1 .. Last_In_Data loop
3503 Matched := Try (S);
3504 exit when Matched;
3505 end loop;
3506 end if;
3507 end if;
3508
3509 -- Matched has its value
3510
3511 for J in Last_Paren + 1 .. Matches'Last loop
3512 Matches_Full (J) := No_Match;
3513 end loop;
3514
3515 Matches := Matches_Full (Matches'Range);
3516 end Match;
3517
3518 -----------
3519 -- Match --
3520 -----------
3521
3522 function Match
3523 (Self : Pattern_Matcher;
3524 Data : String;
3525 Data_First : Integer := -1;
3526 Data_Last : Positive := Positive'Last) return Natural
3527 is
3528 Matches : Match_Array (0 .. 0);
3529
3530 begin
3531 Match (Self, Data, Matches, Data_First, Data_Last);
3532 if Matches (0) = No_Match then
3533 return Data'First - 1;
3534 else
3535 return Matches (0).First;
3536 end if;
3537 end Match;
3538
3539 function Match
3540 (Self : Pattern_Matcher;
3541 Data : String;
3542 Data_First : Integer := -1;
3543 Data_Last : Positive := Positive'Last) return Boolean
3544 is
3545 Matches : Match_Array (0 .. 0);
3546
3547 begin
3548 Match (Self, Data, Matches, Data_First, Data_Last);
3549 return Matches (0).First >= Data'First;
3550 end Match;
3551
3552 procedure Match
3553 (Expression : String;
3554 Data : String;
3555 Matches : out Match_Array;
3556 Size : Program_Size := Auto_Size;
3557 Data_First : Integer := -1;
3558 Data_Last : Positive := Positive'Last)
3559 is
3560 PM : Pattern_Matcher (Size);
3561 Finalize_Size : Program_Size;
3562 pragma Unreferenced (Finalize_Size);
3563 begin
3564 if Size = 0 then
3565 Match (Compile (Expression), Data, Matches, Data_First, Data_Last);
3566 else
3567 Compile (PM, Expression, Finalize_Size);
3568 Match (PM, Data, Matches, Data_First, Data_Last);
3569 end if;
3570 end Match;
3571
3572 -----------
3573 -- Match --
3574 -----------
3575
3576 function Match
3577 (Expression : String;
3578 Data : String;
3579 Size : Program_Size := Auto_Size;
3580 Data_First : Integer := -1;
3581 Data_Last : Positive := Positive'Last) return Natural
3582 is
3583 PM : Pattern_Matcher (Size);
3584 Final_Size : Program_Size;
3585 pragma Unreferenced (Final_Size);
3586 begin
3587 if Size = 0 then
3588 return Match (Compile (Expression), Data, Data_First, Data_Last);
3589 else
3590 Compile (PM, Expression, Final_Size);
3591 return Match (PM, Data, Data_First, Data_Last);
3592 end if;
3593 end Match;
3594
3595 -----------
3596 -- Match --
3597 -----------
3598
3599 function Match
3600 (Expression : String;
3601 Data : String;
3602 Size : Program_Size := Auto_Size;
3603 Data_First : Integer := -1;
3604 Data_Last : Positive := Positive'Last) return Boolean
3605 is
3606 Matches : Match_Array (0 .. 0);
3607 PM : Pattern_Matcher (Size);
3608 Final_Size : Program_Size;
3609 pragma Unreferenced (Final_Size);
3610 begin
3611 if Size = 0 then
3612 Match (Compile (Expression), Data, Matches, Data_First, Data_Last);
3613 else
3614 Compile (PM, Expression, Final_Size);
3615 Match (PM, Data, Matches, Data_First, Data_Last);
3616 end if;
3617
3618 return Matches (0).First >= Data'First;
3619 end Match;
3620
3621 -------------
3622 -- Operand --
3623 -------------
3624
3625 function Operand (P : Pointer) return Pointer is
3626 begin
3627 return P + Next_Pointer_Bytes;
3628 end Operand;
3629
3630 --------------
3631 -- Optimize --
3632 --------------
3633
3634 procedure Optimize (Self : in out Pattern_Matcher) is
3635 Scan : Pointer;
3636 Program : Program_Data renames Self.Program;
3637
3638 begin
3639 -- Start with safe defaults (no optimization):
3640 -- * No known first character of match
3641 -- * Does not necessarily start at beginning of line
3642 -- * No string known that has to appear in data
3643
3644 Self.First := ASCII.NUL;
3645 Self.Anchored := False;
3646 Self.Must_Have := Program'Last + 1;
3647 Self.Must_Have_Length := 0;
3648
3649 Scan := Program_First; -- First instruction (can be anything)
3650
3651 if Program (Scan) = EXACT then
3652 Self.First := Program (String_Operand (Scan));
3653
3654 elsif Program (Scan) = BOL
3655 or else Program (Scan) = SBOL
3656 or else Program (Scan) = MBOL
3657 then
3658 Self.Anchored := True;
3659 end if;
3660 end Optimize;
3661
3662 -----------------
3663 -- Paren_Count --
3664 -----------------
3665
3666 function Paren_Count (Regexp : Pattern_Matcher) return Match_Count is
3667 begin
3668 return Regexp.Paren_Count;
3669 end Paren_Count;
3670
3671 -----------
3672 -- Quote --
3673 -----------
3674
3675 function Quote (Str : String) return String is
3676 S : String (1 .. Str'Length * 2);
3677 Last : Natural := 0;
3678
3679 begin
3680 for J in Str'Range loop
3681 case Str (J) is
3682 when '^' | '$' | '|' | '*' | '+' | '?' | '{' |
3683 '}' | '[' | ']' | '(' | ')' | '\' | '.' =>
3684
3685 S (Last + 1) := '\';
3686 S (Last + 2) := Str (J);
3687 Last := Last + 2;
3688
3689 when others =>
3690 S (Last + 1) := Str (J);
3691 Last := Last + 1;
3692 end case;
3693 end loop;
3694
3695 return S (1 .. Last);
3696 end Quote;
3697
3698 ------------------
3699 -- Read_Natural --
3700 ------------------
3701
3702 function Read_Natural
3703 (Program : Program_Data;
3704 IP : Pointer) return Natural
3705 is
3706 begin
3707 return Character'Pos (Program (IP)) +
3708 256 * Character'Pos (Program (IP + 1));
3709 end Read_Natural;
3710
3711 -----------------
3712 -- Reset_Class --
3713 -----------------
3714
3715 procedure Reset_Class (Bitmap : out Character_Class) is
3716 begin
3717 Bitmap := (others => 0);
3718 end Reset_Class;
3719
3720 ------------------
3721 -- Set_In_Class --
3722 ------------------
3723
3724 procedure Set_In_Class
3725 (Bitmap : in out Character_Class;
3726 C : Character)
3727 is
3728 Value : constant Class_Byte := Character'Pos (C);
3729 begin
3730 Bitmap (Value / 8) := Bitmap (Value / 8)
3731 or Bit_Conversion (Value mod 8);
3732 end Set_In_Class;
3733
3734 -------------------
3735 -- String_Length --
3736 -------------------
3737
3738 function String_Length
3739 (Program : Program_Data;
3740 P : Pointer) return Program_Size
3741 is
3742 begin
3743 pragma Assert (Program (P) = EXACT or else Program (P) = EXACTF);
3744 return Character'Pos (Program (P + Next_Pointer_Bytes));
3745 end String_Length;
3746
3747 --------------------
3748 -- String_Operand --
3749 --------------------
3750
3751 function String_Operand (P : Pointer) return Pointer is
3752 begin
3753 return P + 4;
3754 end String_Operand;
3755
3756 end System.Regpat;
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