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------------------------------------------------------------------------------ -- -- -- GNAT LIBRARY COMPONENTS -- -- -- -- G N A T . R E G P A T -- -- -- -- B o d y -- -- -- -- Copyright (C) 1986 by University of Toronto. -- -- Copyright (C) 1999-2011, AdaCore -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- <http://www.gnu.org/licenses/>. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- This is an altered Ada 95 version of the original V8 style regular -- expression library written in C by Henry Spencer. Apart from the -- translation to Ada, the interface has been considerably changed to -- use the Ada String type instead of C-style nul-terminated strings. -- Beware that some of this code is subtly aware of the way operator -- precedence is structured in regular expressions. Serious changes in -- regular-expression syntax might require a total rethink. with System.IO; use System.IO; with Ada.Characters.Handling; use Ada.Characters.Handling; with Ada.Unchecked_Conversion; package body System.Regpat is Debug : constant Boolean := False; -- Set to True to activate debug traces. This is normally set to constant -- False to simply delete all the trace code. It is to be edited to True -- for internal debugging of the package. ---------------------------- -- Implementation details -- ---------------------------- -- This is essentially a linear encoding of a nondeterministic -- finite-state machine, also known as syntax charts or -- "railroad normal form" in parsing technology. -- Each node is an opcode plus a "next" pointer, possibly plus an -- operand. "Next" pointers of all nodes except BRANCH implement -- concatenation; a "next" pointer with a BRANCH on both ends of it -- is connecting two alternatives. -- The operand of some types of node is a literal string; for others, -- it is a node leading into a sub-FSM. In particular, the operand of -- a BRANCH node is the first node of the branch. -- (NB this is *not* a tree structure: the tail of the branch connects -- to the thing following the set of BRANCHes). -- You can see the exact byte-compiled version by using the Dump -- subprogram. However, here are a few examples: -- (a|b): 1 : BRANCH (next at 9) -- 4 : EXACT (next at 17) operand=a -- 9 : BRANCH (next at 17) -- 12 : EXACT (next at 17) operand=b -- 17 : EOP (next at 0) -- -- (ab)*: 1 : CURLYX (next at 25) { 0, 32767} -- 8 : OPEN 1 (next at 12) -- 12 : EXACT (next at 18) operand=ab -- 18 : CLOSE 1 (next at 22) -- 22 : WHILEM (next at 0) -- 25 : NOTHING (next at 28) -- 28 : EOP (next at 0) -- The opcodes are: type Opcode is -- Name Operand? Meaning (EOP, -- no End of program MINMOD, -- no Next operator is not greedy -- Classes of characters ANY, -- no Match any one character except newline SANY, -- no Match any character, including new line ANYOF, -- class Match any character in this class EXACT, -- str Match this string exactly EXACTF, -- str Match this string (case-folding is one) NOTHING, -- no Match empty string SPACE, -- no Match any whitespace character NSPACE, -- no Match any non-whitespace character DIGIT, -- no Match any numeric character NDIGIT, -- no Match any non-numeric character ALNUM, -- no Match any alphanumeric character NALNUM, -- no Match any non-alphanumeric character -- Branches BRANCH, -- node Match this alternative, or the next -- Simple loops (when the following node is one character in length) STAR, -- node Match this simple thing 0 or more times PLUS, -- node Match this simple thing 1 or more times CURLY, -- 2num node Match this simple thing between n and m times. -- Complex loops CURLYX, -- 2num node Match this complex thing {n,m} times -- The nums are coded on two characters each WHILEM, -- no Do curly processing and see if rest matches -- Matches after or before a word BOL, -- no Match "" at beginning of line MBOL, -- no Same, assuming multiline (match after \n) SBOL, -- no Same, assuming single line (don't match at \n) EOL, -- no Match "" at end of line MEOL, -- no Same, assuming multiline (match before \n) SEOL, -- no Same, assuming single line (don't match at \n) BOUND, -- no Match "" at any word boundary NBOUND, -- no Match "" at any word non-boundary -- Parenthesis groups handling REFF, -- num Match some already matched string, folded OPEN, -- num Mark this point in input as start of #n CLOSE); -- num Analogous to OPEN for Opcode'Size use 8; -- Opcode notes: -- BRANCH -- The set of branches constituting a single choice are hooked -- together with their "next" pointers, since precedence prevents -- anything being concatenated to any individual branch. The -- "next" pointer of the last BRANCH in a choice points to the -- thing following the whole choice. This is also where the -- final "next" pointer of each individual branch points; each -- branch starts with the operand node of a BRANCH node. -- STAR,PLUS -- '?', and complex '*' and '+', are implemented with CURLYX. -- branches. Simple cases (one character per match) are implemented with -- STAR and PLUS for speed and to minimize recursive plunges. -- OPEN,CLOSE -- ...are numbered at compile time. -- EXACT, EXACTF -- There are in fact two arguments, the first one is the length (minus -- one of the string argument), coded on one character, the second -- argument is the string itself, coded on length + 1 characters. -- A node is one char of opcode followed by two chars of "next" pointer. -- "Next" pointers are stored as two 8-bit pieces, high order first. The -- value is a positive offset from the opcode of the node containing it. -- An operand, if any, simply follows the node. (Note that much of the -- code generation knows about this implicit relationship.) -- Using two bytes for the "next" pointer is vast overkill for most -- things, but allows patterns to get big without disasters. Next_Pointer_Bytes : constant := 3; -- Points after the "next pointer" data. An instruction is therefore: -- 1 byte: instruction opcode -- 2 bytes: pointer to next instruction -- * bytes: optional data for the instruction ----------------------- -- Character classes -- ----------------------- -- This is the implementation for character classes ([...]) in the -- syntax for regular expressions. Each character (0..256) has an -- entry into the table. This makes for a very fast matching -- algorithm. type Class_Byte is mod 256; type Character_Class is array (Class_Byte range 0 .. 31) of Class_Byte; type Bit_Conversion_Array is array (Class_Byte range 0 .. 7) of Class_Byte; Bit_Conversion : constant Bit_Conversion_Array := (1, 2, 4, 8, 16, 32, 64, 128); type Std_Class is (ANYOF_NONE, ANYOF_ALNUM, -- Alphanumeric class [a-zA-Z0-9] ANYOF_NALNUM, ANYOF_SPACE, -- Space class [ \t\n\r\f] ANYOF_NSPACE, ANYOF_DIGIT, -- Digit class [0-9] ANYOF_NDIGIT, ANYOF_ALNUMC, -- Alphanumeric class [a-zA-Z0-9] ANYOF_NALNUMC, ANYOF_ALPHA, -- Alpha class [a-zA-Z] ANYOF_NALPHA, ANYOF_ASCII, -- Ascii class (7 bits) 0..127 ANYOF_NASCII, ANYOF_CNTRL, -- Control class ANYOF_NCNTRL, ANYOF_GRAPH, -- Graphic class ANYOF_NGRAPH, ANYOF_LOWER, -- Lower case class [a-z] ANYOF_NLOWER, ANYOF_PRINT, -- printable class ANYOF_NPRINT, ANYOF_PUNCT, -- ANYOF_NPUNCT, ANYOF_UPPER, -- Upper case class [A-Z] ANYOF_NUPPER, ANYOF_XDIGIT, -- Hexadecimal digit ANYOF_NXDIGIT ); procedure Set_In_Class (Bitmap : in out Character_Class; C : Character); -- Set the entry to True for C in the class Bitmap function Get_From_Class (Bitmap : Character_Class; C : Character) return Boolean; -- Return True if the entry is set for C in the class Bitmap procedure Reset_Class (Bitmap : out Character_Class); -- Clear all the entries in the class Bitmap pragma Inline (Set_In_Class); pragma Inline (Get_From_Class); pragma Inline (Reset_Class); ----------------------- -- Local Subprograms -- ----------------------- function "=" (Left : Character; Right : Opcode) return Boolean; function Is_Alnum (C : Character) return Boolean; -- Return True if C is an alphanum character or an underscore ('_') function Is_White_Space (C : Character) return Boolean; -- Return True if C is a whitespace character function Is_Printable (C : Character) return Boolean; -- Return True if C is a printable character function Operand (P : Pointer) return Pointer; -- Return a pointer to the first operand of the node at P function String_Length (Program : Program_Data; P : Pointer) return Program_Size; -- Return the length of the string argument of the node at P function String_Operand (P : Pointer) return Pointer; -- Return a pointer to the string argument of the node at P procedure Bitmap_Operand (Program : Program_Data; P : Pointer; Op : out Character_Class); -- Return a pointer to the string argument of the node at P function Get_Next (Program : Program_Data; IP : Pointer) return Pointer; -- Dig the next instruction pointer out of a node procedure Optimize (Self : in out Pattern_Matcher); -- Optimize a Pattern_Matcher by noting certain special cases function Read_Natural (Program : Program_Data; IP : Pointer) return Natural; -- Return the 2-byte natural coded at position IP -- All of the subprograms above are tiny and should be inlined pragma Inline ("="); pragma Inline (Is_Alnum); pragma Inline (Is_White_Space); pragma Inline (Get_Next); pragma Inline (Operand); pragma Inline (Read_Natural); pragma Inline (String_Length); pragma Inline (String_Operand); type Expression_Flags is record Has_Width, -- Known never to match null string Simple, -- Simple enough to be STAR/PLUS operand SP_Start : Boolean; -- Starts with * or + end record; Worst_Expression : constant Expression_Flags := (others => False); -- Worst case procedure Dump_Until (Program : Program_Data; Index : in out Pointer; Till : Pointer; Indent : Natural; Do_Print : Boolean := True); -- Dump the program until the node Till (not included) is met. Every line -- is indented with Index spaces at the beginning Dumps till the end if -- Till is 0. procedure Dump_Operation (Program : Program_Data; Index : Pointer; Indent : Natural); -- Same as above, but only dumps a single operation, and compute its -- indentation from the program. --------- -- "=" -- --------- function "=" (Left : Character; Right : Opcode) return Boolean is begin return Character'Pos (Left) = Opcode'Pos (Right); end "="; -------------------- -- Bitmap_Operand -- -------------------- procedure Bitmap_Operand (Program : Program_Data; P : Pointer; Op : out Character_Class) is function Convert is new Ada.Unchecked_Conversion (Program_Data, Character_Class); begin Op (0 .. 31) := Convert (Program (P + Next_Pointer_Bytes .. P + 34)); end Bitmap_Operand; ------------- -- Compile -- ------------- procedure Compile (Matcher : out Pattern_Matcher; Expression : String; Final_Code_Size : out Program_Size; Flags : Regexp_Flags := No_Flags) is -- We can't allocate space until we know how big the compiled form -- will be, but we can't compile it (and thus know how big it is) -- until we've got a place to put the code. So we cheat: we compile -- it twice, once with code generation turned off and size counting -- turned on, and once "for real". -- This also means that we don't allocate space until we are sure -- that the thing really will compile successfully, and we never -- have to move the code and thus invalidate pointers into it. -- Beware that the optimization-preparation code in here knows -- about some of the structure of the compiled regexp. PM : Pattern_Matcher renames Matcher; Program : Program_Data renames PM.Program; Emit_Ptr : Pointer := Program_First; Parse_Pos : Natural := Expression'First; -- Input-scan pointer Parse_End : constant Natural := Expression'Last; ---------------------------- -- Subprograms for Create -- ---------------------------- procedure Emit (B : Character); -- Output the Character B to the Program. If code-generation is -- disabled, simply increments the program counter. function Emit_Node (Op : Opcode) return Pointer; -- If code-generation is enabled, Emit_Node outputs the -- opcode Op and reserves space for a pointer to the next node. -- Return value is the location of new opcode, i.e. old Emit_Ptr. procedure Emit_Natural (IP : Pointer; N : Natural); -- Split N on two characters at position IP procedure Emit_Class (Bitmap : Character_Class); -- Emits a character class procedure Case_Emit (C : Character); -- Emit C, after converting is to lower-case if the regular -- expression is case insensitive. procedure Parse (Parenthesized : Boolean; Flags : out Expression_Flags; IP : out Pointer); -- Parse regular expression, i.e. main body or parenthesized thing -- Caller must absorb opening parenthesis. procedure Parse_Branch (Flags : out Expression_Flags; First : Boolean; IP : out Pointer); -- Implements the concatenation operator and handles '|' -- First should be true if this is the first item of the alternative. procedure Parse_Piece (Expr_Flags : out Expression_Flags; IP : out Pointer); -- Parse something followed by possible [*+?] procedure Parse_Atom (Expr_Flags : out Expression_Flags; IP : out Pointer); -- Parse_Atom is the lowest level parse procedure. -- -- Optimization: Gobbles an entire sequence of ordinary characters so -- that it can turn them into a single node, which is smaller to store -- and faster to run. Backslashed characters are exceptions, each -- becoming a separate node; the code is simpler that way and it's -- not worth fixing. procedure Insert_Operator (Op : Opcode; Operand : Pointer; Greedy : Boolean := True); -- Insert_Operator inserts an operator in front of an already-emitted -- operand and relocates the operand. This applies to PLUS and STAR. -- If Minmod is True, then the operator is non-greedy. function Insert_Operator_Before (Op : Opcode; Operand : Pointer; Greedy : Boolean; Opsize : Pointer) return Pointer; -- Insert an operator before Operand (and move the latter forward in the -- program). Opsize is the size needed to represent the operator. This -- returns the position at which the operator was inserted, and moves -- Emit_Ptr after the new position of the operand. procedure Insert_Curly_Operator (Op : Opcode; Min : Natural; Max : Natural; Operand : Pointer; Greedy : Boolean := True); -- Insert an operator for CURLY ({Min}, {Min,} or {Min,Max}). -- If Minmod is True, then the operator is non-greedy. procedure Link_Tail (P, Val : Pointer); -- Link_Tail sets the next-pointer at the end of a node chain procedure Link_Operand_Tail (P, Val : Pointer); -- Link_Tail on operand of first argument; noop if operand-less procedure Fail (M : String); pragma No_Return (Fail); -- Fail with a diagnostic message, if possible function Is_Curly_Operator (IP : Natural) return Boolean; -- Return True if IP is looking at a '{' that is the beginning -- of a curly operator, i.e. it matches {\d+,?\d*} function Is_Mult (IP : Natural) return Boolean; -- Return True if C is a regexp multiplier: '+', '*' or '?' procedure Get_Curly_Arguments (IP : Natural; Min : out Natural; Max : out Natural; Greedy : out Boolean); -- Parse the argument list for a curly operator. -- It is assumed that IP is indeed pointing at a valid operator. -- So what is IP and how come IP is not referenced in the body ??? procedure Parse_Character_Class (IP : out Pointer); -- Parse a character class. -- The calling subprogram should consume the opening '[' before. procedure Parse_Literal (Expr_Flags : out Expression_Flags; IP : out Pointer); -- Parse_Literal encodes a string of characters to be matched exactly function Parse_Posix_Character_Class return Std_Class; -- Parse a posix character class, like [:alpha:] or [:^alpha:]. -- The caller is supposed to absorb the opening [. pragma Inline (Is_Mult); pragma Inline (Emit_Natural); pragma Inline (Parse_Character_Class); -- since used only once --------------- -- Case_Emit -- --------------- procedure Case_Emit (C : Character) is begin if (Flags and Case_Insensitive) /= 0 then Emit (To_Lower (C)); else -- Dump current character Emit (C); end if; end Case_Emit; ---------- -- Emit -- ---------- procedure Emit (B : Character) is begin if Emit_Ptr <= PM.Size then Program (Emit_Ptr) := B; end if; Emit_Ptr := Emit_Ptr + 1; end Emit; ---------------- -- Emit_Class -- ---------------- procedure Emit_Class (Bitmap : Character_Class) is subtype Program31 is Program_Data (0 .. 31); function Convert is new Ada.Unchecked_Conversion (Character_Class, Program31); begin -- What is the mysterious constant 31 here??? Can't it be expressed -- symbolically (size of integer - 1 or some such???). In any case -- it should be declared as a constant (and referenced presumably -- as this constant + 1 below. if Emit_Ptr + 31 <= PM.Size then Program (Emit_Ptr .. Emit_Ptr + 31) := Convert (Bitmap); end if; Emit_Ptr := Emit_Ptr + 32; end Emit_Class; ------------------ -- Emit_Natural -- ------------------ procedure Emit_Natural (IP : Pointer; N : Natural) is begin if IP + 1 <= PM.Size then Program (IP + 1) := Character'Val (N / 256); Program (IP) := Character'Val (N mod 256); end if; end Emit_Natural; --------------- -- Emit_Node -- --------------- function Emit_Node (Op : Opcode) return Pointer is Result : constant Pointer := Emit_Ptr; begin if Emit_Ptr + 2 <= PM.Size then Program (Emit_Ptr) := Character'Val (Opcode'Pos (Op)); Program (Emit_Ptr + 1) := ASCII.NUL; Program (Emit_Ptr + 2) := ASCII.NUL; end if; Emit_Ptr := Emit_Ptr + Next_Pointer_Bytes; return Result; end Emit_Node; ---------- -- Fail -- ---------- procedure Fail (M : String) is begin raise Expression_Error with M; end Fail; ------------------------- -- Get_Curly_Arguments -- ------------------------- procedure Get_Curly_Arguments (IP : Natural; Min : out Natural; Max : out Natural; Greedy : out Boolean) is pragma Unreferenced (IP); Save_Pos : Natural := Parse_Pos + 1; begin Min := 0; Max := Max_Curly_Repeat; while Expression (Parse_Pos) /= '}' and then Expression (Parse_Pos) /= ',' loop Parse_Pos := Parse_Pos + 1; end loop; Min := Natural'Value (Expression (Save_Pos .. Parse_Pos - 1)); if Expression (Parse_Pos) = ',' then Save_Pos := Parse_Pos + 1; while Expression (Parse_Pos) /= '}' loop Parse_Pos := Parse_Pos + 1; end loop; if Save_Pos /= Parse_Pos then Max := Natural'Value (Expression (Save_Pos .. Parse_Pos - 1)); end if; else Max := Min; end if; if Parse_Pos < Expression'Last and then Expression (Parse_Pos + 1) = '?' then Greedy := False; Parse_Pos := Parse_Pos + 1; else Greedy := True; end if; end Get_Curly_Arguments; --------------------------- -- Insert_Curly_Operator -- --------------------------- procedure Insert_Curly_Operator (Op : Opcode; Min : Natural; Max : Natural; Operand : Pointer; Greedy : Boolean := True) is Old : Pointer; begin Old := Insert_Operator_Before (Op, Operand, Greedy, Opsize => 7); Emit_Natural (Old + Next_Pointer_Bytes, Min); Emit_Natural (Old + Next_Pointer_Bytes + 2, Max); end Insert_Curly_Operator; ---------------------------- -- Insert_Operator_Before -- ---------------------------- function Insert_Operator_Before (Op : Opcode; Operand : Pointer; Greedy : Boolean; Opsize : Pointer) return Pointer is Dest : constant Pointer := Emit_Ptr; Old : Pointer; Size : Pointer := Opsize; begin -- If not greedy, we have to emit another opcode first if not Greedy then Size := Size + Next_Pointer_Bytes; end if; -- Move the operand in the byte-compilation, so that we can insert -- the operator before it. if Emit_Ptr + Size <= PM.Size then Program (Operand + Size .. Emit_Ptr + Size) := Program (Operand .. Emit_Ptr); end if; -- Insert the operator at the position previously occupied by the -- operand. Emit_Ptr := Operand; if not Greedy then Old := Emit_Node (MINMOD); Link_Tail (Old, Old + Next_Pointer_Bytes); end if; Old := Emit_Node (Op); Emit_Ptr := Dest + Size; return Old; end Insert_Operator_Before; --------------------- -- Insert_Operator -- --------------------- procedure Insert_Operator (Op : Opcode; Operand : Pointer; Greedy : Boolean := True) is Discard : Pointer; pragma Warnings (Off, Discard); begin Discard := Insert_Operator_Before (Op, Operand, Greedy, Opsize => Next_Pointer_Bytes); end Insert_Operator; ----------------------- -- Is_Curly_Operator -- ----------------------- function Is_Curly_Operator (IP : Natural) return Boolean is Scan : Natural := IP; begin if Expression (Scan) /= '{' or else Scan + 2 > Expression'Last or else not Is_Digit (Expression (Scan + 1)) then return False; end if; Scan := Scan + 1; -- The first digit loop Scan := Scan + 1; if Scan > Expression'Last then return False; end if; exit when not Is_Digit (Expression (Scan)); end loop; if Expression (Scan) = ',' then loop Scan := Scan + 1; if Scan > Expression'Last then return False; end if; exit when not Is_Digit (Expression (Scan)); end loop; end if; return Expression (Scan) = '}'; end Is_Curly_Operator; ------------- -- Is_Mult -- ------------- function Is_Mult (IP : Natural) return Boolean is C : constant Character := Expression (IP); begin return C = '*' or else C = '+' or else C = '?' or else (C = '{' and then Is_Curly_Operator (IP)); end Is_Mult; ----------------------- -- Link_Operand_Tail -- ----------------------- procedure Link_Operand_Tail (P, Val : Pointer) is begin if P <= PM.Size and then Program (P) = BRANCH then Link_Tail (Operand (P), Val); end if; end Link_Operand_Tail; --------------- -- Link_Tail -- --------------- procedure Link_Tail (P, Val : Pointer) is Scan : Pointer; Temp : Pointer; Offset : Pointer; begin -- Find last node (the size of the pattern matcher might be too -- small, so don't try to read past its end). Scan := P; while Scan + Next_Pointer_Bytes <= PM.Size loop Temp := Get_Next (Program, Scan); exit when Temp = Scan; Scan := Temp; end loop; Offset := Val - Scan; Emit_Natural (Scan + 1, Natural (Offset)); end Link_Tail; ----------- -- Parse -- ----------- -- Combining parenthesis handling with the base level of regular -- expression is a trifle forced, but the need to tie the tails of the -- the branches to what follows makes it hard to avoid. procedure Parse (Parenthesized : Boolean; Flags : out Expression_Flags; IP : out Pointer) is E : String renames Expression; Br, Br2 : Pointer; Ender : Pointer; Par_No : Natural; New_Flags : Expression_Flags; Have_Branch : Boolean := False; begin Flags := (Has_Width => True, others => False); -- Tentatively -- Make an OPEN node, if parenthesized if Parenthesized then if Matcher.Paren_Count > Max_Paren_Count then Fail ("too many ()"); end if; Par_No := Matcher.Paren_Count + 1; Matcher.Paren_Count := Matcher.Paren_Count + 1; IP := Emit_Node (OPEN); Emit (Character'Val (Par_No)); else IP := 0; Par_No := 0; end if; -- Pick up the branches, linking them together Parse_Branch (New_Flags, True, Br); if Br = 0 then IP := 0; return; end if; if Parse_Pos <= Parse_End and then E (Parse_Pos) = '|' then Insert_Operator (BRANCH, Br); Have_Branch := True; end if; if IP /= 0 then Link_Tail (IP, Br); -- OPEN -> first else IP := Br; end if; if not New_Flags.Has_Width then Flags.Has_Width := False; end if; Flags.SP_Start := Flags.SP_Start or else New_Flags.SP_Start; while Parse_Pos <= Parse_End and then (E (Parse_Pos) = '|') loop Parse_Pos := Parse_Pos + 1; Parse_Branch (New_Flags, False, Br); if Br = 0 then IP := 0; return; end if; Link_Tail (IP, Br); -- BRANCH -> BRANCH if not New_Flags.Has_Width then Flags.Has_Width := False; end if; Flags.SP_Start := Flags.SP_Start or else New_Flags.SP_Start; end loop; -- Make a closing node, and hook it on the end if Parenthesized then Ender := Emit_Node (CLOSE); Emit (Character'Val (Par_No)); else Ender := Emit_Node (EOP); end if; Link_Tail (IP, Ender); if Have_Branch and then Emit_Ptr <= PM.Size then -- Hook the tails of the branches to the closing node Br := IP; loop Link_Operand_Tail (Br, Ender); Br2 := Get_Next (Program, Br); exit when Br2 = Br; Br := Br2; end loop; end if; -- Check for proper termination if Parenthesized then if Parse_Pos > Parse_End or else E (Parse_Pos) /= ')' then Fail ("unmatched ()"); end if; Parse_Pos := Parse_Pos + 1; elsif Parse_Pos <= Parse_End then if E (Parse_Pos) = ')' then Fail ("unmatched ()"); else Fail ("junk on end"); -- "Can't happen" end if; end if; end Parse; ---------------- -- Parse_Atom -- ---------------- procedure Parse_Atom (Expr_Flags : out Expression_Flags; IP : out Pointer) is C : Character; begin -- Tentatively set worst expression case Expr_Flags := Worst_Expression; C := Expression (Parse_Pos); Parse_Pos := Parse_Pos + 1; case (C) is when '^' => IP := Emit_Node (if (Flags and Multiple_Lines) /= 0 then MBOL elsif (Flags and Single_Line) /= 0 then SBOL else BOL); when '$' => IP := Emit_Node (if (Flags and Multiple_Lines) /= 0 then MEOL elsif (Flags and Single_Line) /= 0 then SEOL else EOL); when '.' => IP := Emit_Node (if (Flags and Single_Line) /= 0 then SANY else ANY); Expr_Flags.Has_Width := True; Expr_Flags.Simple := True; when '[' => Parse_Character_Class (IP); Expr_Flags.Has_Width := True; Expr_Flags.Simple := True; when '(' => declare New_Flags : Expression_Flags; begin Parse (True, New_Flags, IP); if IP = 0 then return; end if; Expr_Flags.Has_Width := Expr_Flags.Has_Width or else New_Flags.Has_Width; Expr_Flags.SP_Start := Expr_Flags.SP_Start or else New_Flags.SP_Start; end; when '|' | ASCII.LF | ')' => Fail ("internal urp"); -- Supposed to be caught earlier when '?' | '+' | '*' => Fail (C & " follows nothing"); when '{' => if Is_Curly_Operator (Parse_Pos - 1) then Fail (C & " follows nothing"); else Parse_Literal (Expr_Flags, IP); end if; when '\' => if Parse_Pos > Parse_End then Fail ("trailing \"); end if; Parse_Pos := Parse_Pos + 1; case Expression (Parse_Pos - 1) is when 'b' => IP := Emit_Node (BOUND); when 'B' => IP := Emit_Node (NBOUND); when 's' => IP := Emit_Node (SPACE); Expr_Flags.Simple := True; Expr_Flags.Has_Width := True; when 'S' => IP := Emit_Node (NSPACE); Expr_Flags.Simple := True; Expr_Flags.Has_Width := True; when 'd' => IP := Emit_Node (DIGIT); Expr_Flags.Simple := True; Expr_Flags.Has_Width := True; when 'D' => IP := Emit_Node (NDIGIT); Expr_Flags.Simple := True; Expr_Flags.Has_Width := True; when 'w' => IP := Emit_Node (ALNUM); Expr_Flags.Simple := True; Expr_Flags.Has_Width := True; when 'W' => IP := Emit_Node (NALNUM); Expr_Flags.Simple := True; Expr_Flags.Has_Width := True; when 'A' => IP := Emit_Node (SBOL); when 'G' => IP := Emit_Node (SEOL); when '0' .. '9' => IP := Emit_Node (REFF); declare Save : constant Natural := Parse_Pos - 1; begin while Parse_Pos <= Expression'Last and then Is_Digit (Expression (Parse_Pos)) loop Parse_Pos := Parse_Pos + 1; end loop; Emit (Character'Val (Natural'Value (Expression (Save .. Parse_Pos - 1)))); end; when others => Parse_Pos := Parse_Pos - 1; Parse_Literal (Expr_Flags, IP); end case; when others => Parse_Literal (Expr_Flags, IP); end case; end Parse_Atom; ------------------ -- Parse_Branch -- ------------------ procedure Parse_Branch (Flags : out Expression_Flags; First : Boolean; IP : out Pointer) is E : String renames Expression; Chain : Pointer; Last : Pointer; New_Flags : Expression_Flags; Discard : Pointer; pragma Warnings (Off, Discard); begin Flags := Worst_Expression; -- Tentatively IP := (if First then Emit_Ptr else Emit_Node (BRANCH)); Chain := 0; while Parse_Pos <= Parse_End and then E (Parse_Pos) /= ')' and then E (Parse_Pos) /= ASCII.LF and then E (Parse_Pos) /= '|' loop Parse_Piece (New_Flags, Last); if Last = 0 then IP := 0; return; end if; Flags.Has_Width := Flags.Has_Width or else New_Flags.Has_Width; if Chain = 0 then -- First piece Flags.SP_Start := Flags.SP_Start or else New_Flags.SP_Start; else Link_Tail (Chain, Last); end if; Chain := Last; end loop; -- Case where loop ran zero CURLY if Chain = 0 then Discard := Emit_Node (NOTHING); end if; end Parse_Branch; --------------------------- -- Parse_Character_Class -- --------------------------- procedure Parse_Character_Class (IP : out Pointer) is Bitmap : Character_Class; Invert : Boolean := False; In_Range : Boolean := False; Named_Class : Std_Class := ANYOF_NONE; Value : Character; Last_Value : Character := ASCII.NUL; begin Reset_Class (Bitmap); -- Do we have an invert character class ? if Parse_Pos <= Parse_End and then Expression (Parse_Pos) = '^' then Invert := True; Parse_Pos := Parse_Pos + 1; end if; -- First character can be ] or - without closing the class if Parse_Pos <= Parse_End and then (Expression (Parse_Pos) = ']' or else Expression (Parse_Pos) = '-') then Set_In_Class (Bitmap, Expression (Parse_Pos)); Parse_Pos := Parse_Pos + 1; end if; -- While we don't have the end of the class while Parse_Pos <= Parse_End and then Expression (Parse_Pos) /= ']' loop Named_Class := ANYOF_NONE; Value := Expression (Parse_Pos); Parse_Pos := Parse_Pos + 1; -- Do we have a Posix character class if Value = '[' then Named_Class := Parse_Posix_Character_Class; elsif Value = '\' then if Parse_Pos = Parse_End then Fail ("Trailing \"); end if; Value := Expression (Parse_Pos); Parse_Pos := Parse_Pos + 1; case Value is when 'w' => Named_Class := ANYOF_ALNUM; when 'W' => Named_Class := ANYOF_NALNUM; when 's' => Named_Class := ANYOF_SPACE; when 'S' => Named_Class := ANYOF_NSPACE; when 'd' => Named_Class := ANYOF_DIGIT; when 'D' => Named_Class := ANYOF_NDIGIT; when 'n' => Value := ASCII.LF; when 'r' => Value := ASCII.CR; when 't' => Value := ASCII.HT; when 'f' => Value := ASCII.FF; when 'e' => Value := ASCII.ESC; when 'a' => Value := ASCII.BEL; -- when 'x' => ??? hexadecimal value -- when 'c' => ??? control character -- when '0'..'9' => ??? octal character when others => null; end case; end if; -- Do we have a character class? if Named_Class /= ANYOF_NONE then -- A range like 'a-\d' or 'a-[:digit:] is not a range if In_Range then Set_In_Class (Bitmap, Last_Value); Set_In_Class (Bitmap, '-'); In_Range := False; end if; -- Expand the range case Named_Class is when ANYOF_NONE => null; when ANYOF_ALNUM | ANYOF_ALNUMC => for Value in Class_Byte'Range loop if Is_Alnum (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_NALNUM | ANYOF_NALNUMC => for Value in Class_Byte'Range loop if not Is_Alnum (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_SPACE => for Value in Class_Byte'Range loop if Is_White_Space (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_NSPACE => for Value in Class_Byte'Range loop if not Is_White_Space (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_DIGIT => for Value in Class_Byte'Range loop if Is_Digit (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_NDIGIT => for Value in Class_Byte'Range loop if not Is_Digit (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_ALPHA => for Value in Class_Byte'Range loop if Is_Letter (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_NALPHA => for Value in Class_Byte'Range loop if not Is_Letter (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_ASCII => for Value in 0 .. 127 loop Set_In_Class (Bitmap, Character'Val (Value)); end loop; when ANYOF_NASCII => for Value in 128 .. 255 loop Set_In_Class (Bitmap, Character'Val (Value)); end loop; when ANYOF_CNTRL => for Value in Class_Byte'Range loop if Is_Control (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_NCNTRL => for Value in Class_Byte'Range loop if not Is_Control (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_GRAPH => for Value in Class_Byte'Range loop if Is_Graphic (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_NGRAPH => for Value in Class_Byte'Range loop if not Is_Graphic (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_LOWER => for Value in Class_Byte'Range loop if Is_Lower (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_NLOWER => for Value in Class_Byte'Range loop if not Is_Lower (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_PRINT => for Value in Class_Byte'Range loop if Is_Printable (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_NPRINT => for Value in Class_Byte'Range loop if not Is_Printable (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_PUNCT => for Value in Class_Byte'Range loop if Is_Printable (Character'Val (Value)) and then not Is_White_Space (Character'Val (Value)) and then not Is_Alnum (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_NPUNCT => for Value in Class_Byte'Range loop if not Is_Printable (Character'Val (Value)) or else Is_White_Space (Character'Val (Value)) or else Is_Alnum (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_UPPER => for Value in Class_Byte'Range loop if Is_Upper (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_NUPPER => for Value in Class_Byte'Range loop if not Is_Upper (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_XDIGIT => for Value in Class_Byte'Range loop if Is_Hexadecimal_Digit (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; when ANYOF_NXDIGIT => for Value in Class_Byte'Range loop if not Is_Hexadecimal_Digit (Character'Val (Value)) then Set_In_Class (Bitmap, Character'Val (Value)); end if; end loop; end case; -- Not a character range elsif not In_Range then Last_Value := Value; if Parse_Pos > Expression'Last then Fail ("Empty character class []"); end if; if Expression (Parse_Pos) = '-' and then Parse_Pos < Parse_End and then Expression (Parse_Pos + 1) /= ']' then Parse_Pos := Parse_Pos + 1; -- Do we have a range like '\d-a' and '[:space:]-a' -- which is not a real range if Named_Class /= ANYOF_NONE then Set_In_Class (Bitmap, '-'); else In_Range := True; end if; else Set_In_Class (Bitmap, Value); end if; -- Else in a character range else if Last_Value > Value then Fail ("Invalid Range [" & Last_Value'Img & "-" & Value'Img & "]"); end if; while Last_Value <= Value loop Set_In_Class (Bitmap, Last_Value); Last_Value := Character'Succ (Last_Value); end loop; In_Range := False; end if; end loop; -- Optimize case-insensitive ranges (put the upper case or lower -- case character into the bitmap) if (Flags and Case_Insensitive) /= 0 then for C in Character'Range loop if Get_From_Class (Bitmap, C) then Set_In_Class (Bitmap, To_Lower (C)); Set_In_Class (Bitmap, To_Upper (C)); end if; end loop; end if; -- Optimize inverted classes if Invert then for J in Bitmap'Range loop Bitmap (J) := not Bitmap (J); end loop; end if; Parse_Pos := Parse_Pos + 1; -- Emit the class IP := Emit_Node (ANYOF); Emit_Class (Bitmap); end Parse_Character_Class; ------------------- -- Parse_Literal -- ------------------- -- This is a bit tricky due to quoted chars and due to -- the multiplier characters '*', '+', and '?' that -- take the SINGLE char previous as their operand. -- On entry, the character at Parse_Pos - 1 is going to go -- into the string, no matter what it is. It could be -- following a \ if Parse_Atom was entered from the '\' case. -- Basic idea is to pick up a good char in C and examine -- the next char. If Is_Mult (C) then twiddle, if it's a \ -- then frozzle and if it's another magic char then push C and -- terminate the string. If none of the above, push C on the -- string and go around again. -- Start_Pos is used to remember where "the current character" -- starts in the string, if due to an Is_Mult we need to back -- up and put the current char in a separate 1-character string. -- When Start_Pos is 0, C is the only char in the string; -- this is used in Is_Mult handling, and in setting the SIMPLE -- flag at the end. procedure Parse_Literal (Expr_Flags : out Expression_Flags; IP : out Pointer) is Start_Pos : Natural := 0; C : Character; Length_Ptr : Pointer; Has_Special_Operator : Boolean := False; begin Parse_Pos := Parse_Pos - 1; -- Look at current character IP := Emit_Node (if (Flags and Case_Insensitive) /= 0 then EXACTF else EXACT); Length_Ptr := Emit_Ptr; Emit_Ptr := String_Operand (IP); Parse_Loop : loop C := Expression (Parse_Pos); -- Get current character case C is when '.' | '[' | '(' | ')' | '|' | ASCII.LF | '$' | '^' => if Start_Pos = 0 then Start_Pos := Parse_Pos; Emit (C); -- First character is always emitted else exit Parse_Loop; -- Else we are done end if; when '?' | '+' | '*' | '{' => if Start_Pos = 0 then Start_Pos := Parse_Pos; Emit (C); -- First character is always emitted -- Are we looking at an operator, or is this -- simply a normal character ? elsif not Is_Mult (Parse_Pos) then Start_Pos := Parse_Pos; Case_Emit (C); else -- We've got something like "abc?d". Mark this as a -- special case. What we want to emit is a first -- constant string for "ab", then one for "c" that will -- ultimately be transformed with a CURLY operator, A -- special case has to be handled for "a?", since there -- is no initial string to emit. Has_Special_Operator := True; exit Parse_Loop; end if; when '\' => Start_Pos := Parse_Pos; if Parse_Pos = Parse_End then Fail ("Trailing \"); else case Expression (Parse_Pos + 1) is when 'b' | 'B' | 's' | 'S' | 'd' | 'D' | 'w' | 'W' | '0' .. '9' | 'G' | 'A' => exit Parse_Loop; when 'n' => Emit (ASCII.LF); when 't' => Emit (ASCII.HT); when 'r' => Emit (ASCII.CR); when 'f' => Emit (ASCII.FF); when 'e' => Emit (ASCII.ESC); when 'a' => Emit (ASCII.BEL); when others => Emit (Expression (Parse_Pos + 1)); end case; Parse_Pos := Parse_Pos + 1; end if; when others => Start_Pos := Parse_Pos; Case_Emit (C); end case; exit Parse_Loop when Emit_Ptr - Length_Ptr = 254; Parse_Pos := Parse_Pos + 1; exit Parse_Loop when Parse_Pos > Parse_End; end loop Parse_Loop; -- Is the string followed by a '*+?{' operator ? If yes, and if there -- is an initial string to emit, do it now. if Has_Special_Operator and then Emit_Ptr >= Length_Ptr + Next_Pointer_Bytes then Emit_Ptr := Emit_Ptr - 1; Parse_Pos := Start_Pos; end if; if Length_Ptr <= PM.Size then Program (Length_Ptr) := Character'Val (Emit_Ptr - Length_Ptr - 2); end if; Expr_Flags.Has_Width := True; -- Slight optimization when there is a single character if Emit_Ptr = Length_Ptr + 2 then Expr_Flags.Simple := True; end if; end Parse_Literal; ----------------- -- Parse_Piece -- ----------------- -- Note that the branching code sequences used for '?' and the -- general cases of '*' and + are somewhat optimized: they use -- the same NOTHING node as both the endmarker for their branch -- list and the body of the last branch. It might seem that -- this node could be dispensed with entirely, but the endmarker -- role is not redundant. procedure Parse_Piece (Expr_Flags : out Expression_Flags; IP : out Pointer) is Op : Character; New_Flags : Expression_Flags; Greedy : Boolean := True; begin Parse_Atom (New_Flags, IP); if IP = 0 then return; end if; if Parse_Pos > Parse_End or else not Is_Mult (Parse_Pos) then Expr_Flags := New_Flags; return; end if; Op := Expression (Parse_Pos); Expr_Flags := (if Op /= '+' then (SP_Start => True, others => False) else (Has_Width => True, others => False)); -- Detect non greedy operators in the easy cases if Op /= '{' and then Parse_Pos + 1 <= Parse_End and then Expression (Parse_Pos + 1) = '?' then Greedy := False; Parse_Pos := Parse_Pos + 1; end if; -- Generate the byte code case Op is when '*' => if New_Flags.Simple then Insert_Operator (STAR, IP, Greedy); else Link_Tail (IP, Emit_Node (WHILEM)); Insert_Curly_Operator (CURLYX, 0, Max_Curly_Repeat, IP, Greedy); Link_Tail (IP, Emit_Node (NOTHING)); end if; when '+' => if New_Flags.Simple then Insert_Operator (PLUS, IP, Greedy); else Link_Tail (IP, Emit_Node (WHILEM)); Insert_Curly_Operator (CURLYX, 1, Max_Curly_Repeat, IP, Greedy); Link_Tail (IP, Emit_Node (NOTHING)); end if; when '?' => if New_Flags.Simple then Insert_Curly_Operator (CURLY, 0, 1, IP, Greedy); else Link_Tail (IP, Emit_Node (WHILEM)); Insert_Curly_Operator (CURLYX, 0, 1, IP, Greedy); Link_Tail (IP, Emit_Node (NOTHING)); end if; when '{' => declare Min, Max : Natural; begin Get_Curly_Arguments (Parse_Pos, Min, Max, Greedy); if New_Flags.Simple then Insert_Curly_Operator (CURLY, Min, Max, IP, Greedy); else Link_Tail (IP, Emit_Node (WHILEM)); Insert_Curly_Operator (CURLYX, Min, Max, IP, Greedy); Link_Tail (IP, Emit_Node (NOTHING)); end if; end; when others => null; end case; Parse_Pos := Parse_Pos + 1; if Parse_Pos <= Parse_End and then Is_Mult (Parse_Pos) then Fail ("nested *+{"); end if; end Parse_Piece; --------------------------------- -- Parse_Posix_Character_Class -- --------------------------------- function Parse_Posix_Character_Class return Std_Class is Invert : Boolean := False; Class : Std_Class := ANYOF_NONE; E : String renames Expression; -- Class names. Note that code assumes that the length of all -- classes starting with the same letter have the same length. Alnum : constant String := "alnum:]"; Alpha : constant String := "alpha:]"; Ascii_C : constant String := "ascii:]"; Cntrl : constant String := "cntrl:]"; Digit : constant String := "digit:]"; Graph : constant String := "graph:]"; Lower : constant String := "lower:]"; Print : constant String := "print:]"; Punct : constant String := "punct:]"; Space : constant String := "space:]"; Upper : constant String := "upper:]"; Word : constant String := "word:]"; Xdigit : constant String := "xdigit:]"; begin -- Case of character class specified if Parse_Pos <= Parse_End and then Expression (Parse_Pos) = ':' then Parse_Pos := Parse_Pos + 1; -- Do we have something like: [[:^alpha:]] if Parse_Pos <= Parse_End and then Expression (Parse_Pos) = '^' then Invert := True; Parse_Pos := Parse_Pos + 1; end if; -- Check for class names based on first letter case Expression (Parse_Pos) is when 'a' => -- All 'a' classes have the same length (Alnum'Length) if Parse_Pos + Alnum'Length - 1 <= Parse_End then if E (Parse_Pos .. Parse_Pos + Alnum'Length - 1) = Alnum then Class := (if Invert then ANYOF_NALNUMC else ANYOF_ALNUMC); Parse_Pos := Parse_Pos + Alnum'Length; elsif E (Parse_Pos .. Parse_Pos + Alpha'Length - 1) = Alpha then Class := (if Invert then ANYOF_NALPHA else ANYOF_ALPHA); Parse_Pos := Parse_Pos + Alpha'Length; elsif E (Parse_Pos .. Parse_Pos + Ascii_C'Length - 1) = Ascii_C then Class := (if Invert then ANYOF_NASCII else ANYOF_ASCII); Parse_Pos := Parse_Pos + Ascii_C'Length; else Fail ("Invalid character class: " & E); end if; else Fail ("Invalid character class: " & E); end if; when 'c' => if Parse_Pos + Cntrl'Length - 1 <= Parse_End and then E (Parse_Pos .. Parse_Pos + Cntrl'Length - 1) = Cntrl then Class := (if Invert then ANYOF_NCNTRL else ANYOF_CNTRL); Parse_Pos := Parse_Pos + Cntrl'Length; else Fail ("Invalid character class: " & E); end if; when 'd' => if Parse_Pos + Digit'Length - 1 <= Parse_End and then E (Parse_Pos .. Parse_Pos + Digit'Length - 1) = Digit then Class := (if Invert then ANYOF_NDIGIT else ANYOF_DIGIT); Parse_Pos := Parse_Pos + Digit'Length; end if; when 'g' => if Parse_Pos + Graph'Length - 1 <= Parse_End and then E (Parse_Pos .. Parse_Pos + Graph'Length - 1) = Graph then Class := (if Invert then ANYOF_NGRAPH else ANYOF_GRAPH); Parse_Pos := Parse_Pos + Graph'Length; else Fail ("Invalid character class: " & E); end if; when 'l' => if Parse_Pos + Lower'Length - 1 <= Parse_End and then E (Parse_Pos .. Parse_Pos + Lower'Length - 1) = Lower then Class := (if Invert then ANYOF_NLOWER else ANYOF_LOWER); Parse_Pos := Parse_Pos + Lower'Length; else Fail ("Invalid character class: " & E); end if; when 'p' => -- All 'p' classes have the same length if Parse_Pos + Print'Length - 1 <= Parse_End then if E (Parse_Pos .. Parse_Pos + Print'Length - 1) = Print then Class := (if Invert then ANYOF_NPRINT else ANYOF_PRINT); Parse_Pos := Parse_Pos + Print'Length; elsif E (Parse_Pos .. Parse_Pos + Punct'Length - 1) = Punct then Class := (if Invert then ANYOF_NPUNCT else ANYOF_PUNCT); Parse_Pos := Parse_Pos + Punct'Length; else Fail ("Invalid character class: " & E); end if; else Fail ("Invalid character class: " & E); end if; when 's' => if Parse_Pos + Space'Length - 1 <= Parse_End and then E (Parse_Pos .. Parse_Pos + Space'Length - 1) = Space then Class := (if Invert then ANYOF_NSPACE else ANYOF_SPACE); Parse_Pos := Parse_Pos + Space'Length; else Fail ("Invalid character class: " & E); end if; when 'u' => if Parse_Pos + Upper'Length - 1 <= Parse_End and then E (Parse_Pos .. Parse_Pos + Upper'Length - 1) = Upper then Class := (if Invert then ANYOF_NUPPER else ANYOF_UPPER); Parse_Pos := Parse_Pos + Upper'Length; else Fail ("Invalid character class: " & E); end if; when 'w' => if Parse_Pos + Word'Length - 1 <= Parse_End and then E (Parse_Pos .. Parse_Pos + Word'Length - 1) = Word then Class := (if Invert then ANYOF_NALNUM else ANYOF_ALNUM); Parse_Pos := Parse_Pos + Word'Length; else Fail ("Invalid character class: " & E); end if; when 'x' => if Parse_Pos + Xdigit'Length - 1 <= Parse_End and then E (Parse_Pos .. Parse_Pos + Xdigit'Length - 1) = Xdigit then Class := (if Invert then ANYOF_NXDIGIT else ANYOF_XDIGIT); Parse_Pos := Parse_Pos + Xdigit'Length; else Fail ("Invalid character class: " & E); end if; when others => Fail ("Invalid character class: " & E); end case; -- Character class not specified else return ANYOF_NONE; end if; return Class; end Parse_Posix_Character_Class; -- Local Declarations Result : Pointer; Expr_Flags : Expression_Flags; pragma Unreferenced (Expr_Flags); -- Start of processing for Compile begin Parse (False, Expr_Flags, Result); if Result = 0 then Fail ("Couldn't compile expression"); end if; Final_Code_Size := Emit_Ptr - 1; -- Do we want to actually compile the expression, or simply get the -- code size ??? if Emit_Ptr <= PM.Size then Optimize (PM); end if; PM.Flags := Flags; end Compile; function Compile (Expression : String; Flags : Regexp_Flags := No_Flags) return Pattern_Matcher is -- Assume the compiled regexp will fit in 1000 chars. If it does not we -- will have to compile a second time once the correct size is known. If -- it fits, we save a significant amount of time by avoiding the second -- compilation. Dummy : Pattern_Matcher (1000); Size : Program_Size; begin Compile (Dummy, Expression, Size, Flags); if Size <= Dummy.Size then return Pattern_Matcher' (Size => Size, First => Dummy.First, Anchored => Dummy.Anchored, Must_Have => Dummy.Must_Have, Must_Have_Length => Dummy.Must_Have_Length, Paren_Count => Dummy.Paren_Count, Flags => Dummy.Flags, Program => Dummy.Program (Dummy.Program'First .. Dummy.Program'First + Size - 1)); else -- We have to recompile now that we know the size -- ??? Can we use Ada 2005's return construct ? declare Result : Pattern_Matcher (Size); begin Compile (Result, Expression, Size, Flags); return Result; end; end if; end Compile; procedure Compile (Matcher : out Pattern_Matcher; Expression : String; Flags : Regexp_Flags := No_Flags) is Size : Program_Size; begin Compile (Matcher, Expression, Size, Flags); if Size > Matcher.Size then raise Expression_Error with "Pattern_Matcher is too small"; end if; end Compile; -------------------- -- Dump_Operation -- -------------------- procedure Dump_Operation (Program : Program_Data; Index : Pointer; Indent : Natural) is Current : Pointer := Index; begin Dump_Until (Program, Current, Current + 1, Indent); end Dump_Operation; ---------------- -- Dump_Until -- ---------------- procedure Dump_Until (Program : Program_Data; Index : in out Pointer; Till : Pointer; Indent : Natural; Do_Print : Boolean := True) is function Image (S : String) return String; -- Remove leading space ----------- -- Image -- ----------- function Image (S : String) return String is begin if S (S'First) = ' ' then return S (S'First + 1 .. S'Last); else return S; end if; end Image; -- Local variables Op : Opcode; Next : Pointer; Length : Pointer; Local_Indent : Natural := Indent; -- Start of processing for Dump_Until begin while Index < Till loop Op := Opcode'Val (Character'Pos ((Program (Index)))); Next := Get_Next (Program, Index); if Do_Print then declare Point : constant String := Pointer'Image (Index); begin Put ((1 .. 4 - Point'Length => ' ') & Point & ":" & (1 .. Local_Indent * 2 => ' ') & Opcode'Image (Op)); end; -- Print the parenthesis number if Op = OPEN or else Op = CLOSE or else Op = REFF then Put (Image (Natural'Image (Character'Pos (Program (Index + Next_Pointer_Bytes))))); end if; if Next = Index then Put (" (-)"); else Put (" (" & Image (Pointer'Image (Next)) & ")"); end if; end if; case Op is when ANYOF => declare Bitmap : Character_Class; Last : Character := ASCII.NUL; Current : Natural := 0; Current_Char : Character; begin Bitmap_Operand (Program, Index, Bitmap); if Do_Print then Put ("["); while Current <= 255 loop Current_Char := Character'Val (Current); -- First item in a range if Get_From_Class (Bitmap, Current_Char) then Last := Current_Char; -- Search for the last item in the range loop Current := Current + 1; exit when Current > 255; Current_Char := Character'Val (Current); exit when not Get_From_Class (Bitmap, Current_Char); end loop; if not Is_Graphic (Last) then Put (Last'Img); else Put (Last); end if; if Character'Succ (Last) /= Current_Char then Put ("\-" & Character'Pred (Current_Char)); end if; else Current := Current + 1; end if; end loop; Put_Line ("]"); end if; Index := Index + Next_Pointer_Bytes + Bitmap'Length; end; when EXACT | EXACTF => Length := String_Length (Program, Index); if Do_Print then Put (" (" & Image (Program_Size'Image (Length + 1)) & " chars) <" & String (Program (String_Operand (Index) .. String_Operand (Index) + Length))); Put_Line (">"); end if; Index := String_Operand (Index) + Length + 1; -- Node operand when BRANCH | STAR | PLUS => if Do_Print then New_Line; end if; Index := Index + Next_Pointer_Bytes; Dump_Until (Program, Index, Pointer'Min (Next, Till), Local_Indent + 1, Do_Print); when CURLY | CURLYX => if Do_Print then Put_Line (" {" & Image (Natural'Image (Read_Natural (Program, Index + Next_Pointer_Bytes))) & "," & Image (Natural'Image (Read_Natural (Program, Index + 5))) & "}"); end if; Index := Index + 7; Dump_Until (Program, Index, Pointer'Min (Next, Till), Local_Indent + 1, Do_Print); when OPEN => if Do_Print then New_Line; end if; Index := Index + 4; Local_Indent := Local_Indent + 1; when CLOSE | REFF => if Do_Print then New_Line; end if; Index := Index + 4; if Op = CLOSE then Local_Indent := Local_Indent - 1; end if; when others => Index := Index + Next_Pointer_Bytes; if Do_Print then New_Line; end if; exit when Op = EOP; end case; end loop; end Dump_Until; ---------- -- Dump -- ---------- procedure Dump (Self : Pattern_Matcher) is Program : Program_Data renames Self.Program; Index : Pointer := Program'First; -- Start of processing for Dump begin Put_Line ("Must start with (Self.First) = " & Character'Image (Self.First)); if (Self.Flags and Case_Insensitive) /= 0 then Put_Line (" Case_Insensitive mode"); end if; if (Self.Flags and Single_Line) /= 0 then Put_Line (" Single_Line mode"); end if; if (Self.Flags and Multiple_Lines) /= 0 then Put_Line (" Multiple_Lines mode"); end if; Dump_Until (Program, Index, Self.Program'Last + 1, 0); end Dump; -------------------- -- Get_From_Class -- -------------------- function Get_From_Class (Bitmap : Character_Class; C : Character) return Boolean is Value : constant Class_Byte := Character'Pos (C); begin return (Bitmap (Value / 8) and Bit_Conversion (Value mod 8)) /= 0; end Get_From_Class; -------------- -- Get_Next -- -------------- function Get_Next (Program : Program_Data; IP : Pointer) return Pointer is begin return IP + Pointer (Read_Natural (Program, IP + 1)); end Get_Next; -------------- -- Is_Alnum -- -------------- function Is_Alnum (C : Character) return Boolean is begin return Is_Alphanumeric (C) or else C = '_'; end Is_Alnum; ------------------ -- Is_Printable -- ------------------ function Is_Printable (C : Character) return Boolean is begin -- Printable if space or graphic character or other whitespace -- Other white space includes (HT/LF/VT/FF/CR = codes 9-13) return C in Character'Val (32) .. Character'Val (126) or else C in ASCII.HT .. ASCII.CR; end Is_Printable; -------------------- -- Is_White_Space -- -------------------- function Is_White_Space (C : Character) return Boolean is begin -- Note: HT = 9, LF = 10, VT = 11, FF = 12, CR = 13 return C = ' ' or else C in ASCII.HT .. ASCII.CR; end Is_White_Space; ----------- -- Match -- ----------- procedure Match (Self : Pattern_Matcher; Data : String; Matches : out Match_Array; Data_First : Integer := -1; Data_Last : Positive := Positive'Last) is Program : Program_Data renames Self.Program; -- Shorter notation First_In_Data : constant Integer := Integer'Max (Data_First, Data'First); Last_In_Data : constant Integer := Integer'Min (Data_Last, Data'Last); -- Global work variables Input_Pos : Natural; -- String-input pointer BOL_Pos : Natural; -- Beginning of input, for ^ check Matched : Boolean := False; -- Until proven True Matches_Full : Match_Array (0 .. Natural'Max (Self.Paren_Count, Matches'Last)); -- Stores the value of all the parenthesis pairs. -- We do not use directly Matches, so that we can also use back -- references (REFF) even if Matches is too small. type Natural_Array is array (Match_Count range <>) of Natural; Matches_Tmp : Natural_Array (Matches_Full'Range); -- Save the opening position of parenthesis Last_Paren : Natural := 0; -- Last parenthesis seen Greedy : Boolean := True; -- True if the next operator should be greedy type Current_Curly_Record; type Current_Curly_Access is access all Current_Curly_Record; type Current_Curly_Record is record Paren_Floor : Natural; -- How far back to strip parenthesis data Cur : Integer; -- How many instances of scan we've matched Min : Natural; -- Minimal number of scans to match Max : Natural; -- Maximal number of scans to match Greedy : Boolean; -- Whether to work our way up or down Scan : Pointer; -- The thing to match Next : Pointer; -- What has to match after it Lastloc : Natural; -- Where we started matching this scan Old_Cc : Current_Curly_Access; -- Before we started this one end record; -- Data used to handle the curly operator and the plus and star -- operators for complex expressions. Current_Curly : Current_Curly_Access := null; -- The curly currently being processed ----------------------- -- Local Subprograms -- ----------------------- function Index (Start : Positive; C : Character) return Natural; -- Find character C in Data starting at Start and return position function Repeat (IP : Pointer; Max : Natural := Natural'Last) return Natural; -- Repeatedly match something simple, report how many -- It only matches on things of length 1. -- Starting from Input_Pos, it matches at most Max CURLY. function Try (Pos : Positive) return Boolean; -- Try to match at specific point function Match (IP : Pointer) return Boolean; -- This is the main matching routine. Conceptually the strategy -- is simple: check to see whether the current node matches, -- call self recursively to see whether the rest matches, -- and then act accordingly. -- -- In practice Match makes some effort to avoid recursion, in -- particular by going through "ordinary" nodes (that don't -- need to know whether the rest of the match failed) by -- using a loop instead of recursion. -- Why is the above comment part of the spec rather than body ??? function Match_Whilem return Boolean; -- Return True if a WHILEM matches the Current_Curly function Recurse_Match (IP : Pointer; From : Natural) return Boolean; pragma Inline (Recurse_Match); -- Calls Match recursively. It saves and restores the parenthesis -- status and location in the input stream correctly, so that -- backtracking is possible function Match_Simple_Operator (Op : Opcode; Scan : Pointer; Next : Pointer; Greedy : Boolean) return Boolean; -- Return True it the simple operator (possibly non-greedy) matches Dump_Indent : Integer := -1; procedure Dump_Current (Scan : Pointer; Prefix : Boolean := True); procedure Dump_Error (Msg : String); -- Debug: print the current context pragma Inline (Index); pragma Inline (Repeat); -- These are two complex functions, but used only once pragma Inline (Match_Whilem); pragma Inline (Match_Simple_Operator); ----------- -- Index -- ----------- function Index (Start : Positive; C : Character) return Natural is begin for J in Start .. Last_In_Data loop if Data (J) = C then return J; end if; end loop; return 0; end Index; ------------------- -- Recurse_Match -- ------------------- function Recurse_Match (IP : Pointer; From : Natural) return Boolean is L : constant Natural := Last_Paren; Tmp_F : constant Match_Array := Matches_Full (From + 1 .. Matches_Full'Last); Start : constant Natural_Array := Matches_Tmp (From + 1 .. Matches_Tmp'Last); Input : constant Natural := Input_Pos; Dump_Indent_Save : constant Integer := Dump_Indent; begin if Match (IP) then return True; end if; Last_Paren := L; Matches_Full (Tmp_F'Range) := Tmp_F; Matches_Tmp (Start'Range) := Start; Input_Pos := Input; Dump_Indent := Dump_Indent_Save; return False; end Recurse_Match; ------------------ -- Dump_Current -- ------------------ procedure Dump_Current (Scan : Pointer; Prefix : Boolean := True) is Length : constant := 10; Pos : constant String := Integer'Image (Input_Pos); begin if Prefix then Put ((1 .. 5 - Pos'Length => ' ')); Put (Pos & " <" & Data (Input_Pos .. Integer'Min (Last_In_Data, Input_Pos + Length - 1))); Put ((1 .. Length - 1 - Last_In_Data + Input_Pos => ' ')); Put ("> |"); else Put (" "); end if; Dump_Operation (Program, Scan, Indent => Dump_Indent); end Dump_Current; ---------------- -- Dump_Error -- ---------------- procedure Dump_Error (Msg : String) is begin Put (" | "); Put ((1 .. Dump_Indent * 2 => ' ')); Put_Line (Msg); end Dump_Error; ----------- -- Match -- ----------- function Match (IP : Pointer) return Boolean is Scan : Pointer := IP; Next : Pointer; Op : Opcode; Result : Boolean; begin Dump_Indent := Dump_Indent + 1; State_Machine : loop pragma Assert (Scan /= 0); -- Determine current opcode and count its usage in debug mode Op := Opcode'Val (Character'Pos (Program (Scan))); -- Calculate offset of next instruction. Second character is most -- significant in Program_Data. Next := Get_Next (Program, Scan); if Debug then Dump_Current (Scan); end if; case Op is when EOP => Dump_Indent := Dump_Indent - 1; return True; -- Success ! when BRANCH => if Program (Next) /= BRANCH then Next := Operand (Scan); -- No choice, avoid recursion else loop if Recurse_Match (Operand (Scan), 0) then Dump_Indent := Dump_Indent - 1; return True; end if; Scan := Get_Next (Program, Scan); exit when Scan = 0 or else Program (Scan) /= BRANCH; end loop; exit State_Machine; end if; when NOTHING => null; when BOL => exit State_Machine when Input_Pos /= BOL_Pos and then ((Self.Flags and Multiple_Lines) = 0 or else Data (Input_Pos - 1) /= ASCII.LF); when MBOL => exit State_Machine when Input_Pos /= BOL_Pos and then Data (Input_Pos - 1) /= ASCII.LF; when SBOL => exit State_Machine when Input_Pos /= BOL_Pos; when EOL => exit State_Machine when Input_Pos <= Data'Last and then ((Self.Flags and Multiple_Lines) = 0 or else Data (Input_Pos) /= ASCII.LF); when MEOL => exit State_Machine when Input_Pos <= Data'Last and then Data (Input_Pos) /= ASCII.LF; when SEOL => exit State_Machine when Input_Pos <= Data'Last; when BOUND | NBOUND => -- Was last char in word ? declare N : Boolean := False; Ln : Boolean := False; begin if Input_Pos /= First_In_Data then N := Is_Alnum (Data (Input_Pos - 1)); end if; Ln := (if Input_Pos > Last_In_Data then False else Is_Alnum (Data (Input_Pos))); if Op = BOUND then if N = Ln then exit State_Machine; end if; else if N /= Ln then exit State_Machine; end if; end if; end; when SPACE => exit State_Machine when Input_Pos > Last_In_Data or else not Is_White_Space (Data (Input_Pos)); Input_Pos := Input_Pos + 1; when NSPACE => exit State_Machine when Input_Pos > Last_In_Data or else Is_White_Space (Data (Input_Pos)); Input_Pos := Input_Pos + 1; when DIGIT => exit State_Machine when Input_Pos > Last_In_Data or else not Is_Digit (Data (Input_Pos)); Input_Pos := Input_Pos + 1; when NDIGIT => exit State_Machine when Input_Pos > Last_In_Data or else Is_Digit (Data (Input_Pos)); Input_Pos := Input_Pos + 1; when ALNUM => exit State_Machine when Input_Pos > Last_In_Data or else not Is_Alnum (Data (Input_Pos)); Input_Pos := Input_Pos + 1; when NALNUM => exit State_Machine when Input_Pos > Last_In_Data or else Is_Alnum (Data (Input_Pos)); Input_Pos := Input_Pos + 1; when ANY => exit State_Machine when Input_Pos > Last_In_Data or else Data (Input_Pos) = ASCII.LF; Input_Pos := Input_Pos + 1; when SANY => exit State_Machine when Input_Pos > Last_In_Data; Input_Pos := Input_Pos + 1; when EXACT => declare Opnd : Pointer := String_Operand (Scan); Current : Positive := Input_Pos; Last : constant Pointer := Opnd + String_Length (Program, Scan); begin while Opnd <= Last loop exit State_Machine when Current > Last_In_Data or else Program (Opnd) /= Data (Current); Current := Current + 1; Opnd := Opnd + 1; end loop; Input_Pos := Current; end; when EXACTF => declare Opnd : Pointer := String_Operand (Scan); Current : Positive := Input_Pos; Last : constant Pointer := Opnd + String_Length (Program, Scan); begin while Opnd <= Last loop exit State_Machine when Current > Last_In_Data or else Program (Opnd) /= To_Lower (Data (Current)); Current := Current + 1; Opnd := Opnd + 1; end loop; Input_Pos := Current; end; when ANYOF => declare Bitmap : Character_Class; begin Bitmap_Operand (Program, Scan, Bitmap); exit State_Machine when Input_Pos > Last_In_Data or else not Get_From_Class (Bitmap, Data (Input_Pos)); Input_Pos := Input_Pos + 1; end; when OPEN => declare No : constant Natural := Character'Pos (Program (Operand (Scan))); begin Matches_Tmp (No) := Input_Pos; end; when CLOSE => declare No : constant Natural := Character'Pos (Program (Operand (Scan))); begin Matches_Full (No) := (Matches_Tmp (No), Input_Pos - 1); if Last_Paren < No then Last_Paren := No; end if; end; when REFF => declare No : constant Natural := Character'Pos (Program (Operand (Scan))); Data_Pos : Natural; begin -- If we haven't seen that parenthesis yet if Last_Paren < No then Dump_Indent := Dump_Indent - 1; if Debug then Dump_Error ("REFF: No match, backtracking"); end if; return False; end if; Data_Pos := Matches_Full (No).First; while Data_Pos <= Matches_Full (No).Last loop if Input_Pos > Last_In_Data or else Data (Input_Pos) /= Data (Data_Pos) then Dump_Indent := Dump_Indent - 1; if Debug then Dump_Error ("REFF: No match, backtracking"); end if; return False; end if; Input_Pos := Input_Pos + 1; Data_Pos := Data_Pos + 1; end loop; end; when MINMOD => Greedy := False; when STAR | PLUS | CURLY => declare Greed : constant Boolean := Greedy; begin Greedy := True; Result := Match_Simple_Operator (Op, Scan, Next, Greed); Dump_Indent := Dump_Indent - 1; return Result; end; when CURLYX => -- Looking at something like: -- 1: CURLYX {n,m} (->4) -- 2: code for complex thing (->3) -- 3: WHILEM (->0) -- 4: NOTHING declare Min : constant Natural := Read_Natural (Program, Scan + Next_Pointer_Bytes); Max : constant Natural := Read_Natural (Program, Scan + Next_Pointer_Bytes + 2); Cc : aliased Current_Curly_Record; Has_Match : Boolean; begin Cc := (Paren_Floor => Last_Paren, Cur => -1, Min => Min, Max => Max, Greedy => Greedy, Scan => Scan + 7, Next => Next, Lastloc => 0, Old_Cc => Current_Curly); Greedy := True; Current_Curly := Cc'Unchecked_Access; Has_Match := Match (Next - Next_Pointer_Bytes); -- Start on the WHILEM Current_Curly := Cc.Old_Cc; Dump_Indent := Dump_Indent - 1; if not Has_Match then if Debug then Dump_Error ("CURLYX failed..."); end if; end if; return Has_Match; end; when WHILEM => Result := Match_Whilem; Dump_Indent := Dump_Indent - 1; if Debug and then not Result then Dump_Error ("WHILEM: no match, backtracking"); end if; return Result; end case; Scan := Next; end loop State_Machine; if Debug then Dump_Error ("failed..."); Dump_Indent := Dump_Indent - 1; end if; -- If we get here, there is no match. For successful matches when EOP -- is the terminating point. return False; end Match; --------------------------- -- Match_Simple_Operator -- --------------------------- function Match_Simple_Operator (Op : Opcode; Scan : Pointer; Next : Pointer; Greedy : Boolean) return Boolean is Next_Char : Character := ASCII.NUL; Next_Char_Known : Boolean := False; No : Integer; -- Can be negative Min : Natural; Max : Natural := Natural'Last; Operand_Code : Pointer; Old : Natural; Last_Pos : Natural; Save : constant Natural := Input_Pos; begin -- Lookahead to avoid useless match attempts when we know what -- character comes next. if Program (Next) = EXACT then Next_Char := Program (String_Operand (Next)); Next_Char_Known := True; end if; -- Find the minimal and maximal values for the operator case Op is when STAR => Min := 0; Operand_Code := Operand (Scan); when PLUS => Min := 1; Operand_Code := Operand (Scan); when others => Min := Read_Natural (Program, Scan + Next_Pointer_Bytes); Max := Read_Natural (Program, Scan + Next_Pointer_Bytes + 2); Operand_Code := Scan + 7; end case; if Debug then Dump_Current (Operand_Code, Prefix => False); end if; -- Non greedy operators if not Greedy then -- Test we can repeat at least Min times if Min /= 0 then No := Repeat (Operand_Code, Min); if No < Min then if Debug then Dump_Error ("failed... matched" & No'Img & " times"); end if; return False; end if; end if; Old := Input_Pos; -- Find the place where 'next' could work if Next_Char_Known then -- Last position to check if Max = Natural'Last then Last_Pos := Last_In_Data; else Last_Pos := Input_Pos + Max; if Last_Pos > Last_In_Data then Last_Pos := Last_In_Data; end if; end if; -- Look for the first possible opportunity if Debug then Dump_Error ("Next_Char must be " & Next_Char); end if; loop -- Find the next possible position while Input_Pos <= Last_Pos and then Data (Input_Pos) /= Next_Char loop Input_Pos := Input_Pos + 1; end loop; if Input_Pos > Last_Pos then return False; end if; -- Check that we still match if we stop at the position we -- just found. declare Num : constant Natural := Input_Pos - Old; begin Input_Pos := Old; if Debug then Dump_Error ("Would we still match at that position?"); end if; if Repeat (Operand_Code, Num) < Num then return False; end if; end; -- Input_Pos now points to the new position if Match (Get_Next (Program, Scan)) then return True; end if; Old := Input_Pos; Input_Pos := Input_Pos + 1; end loop; -- We do not know what the next character is else while Max >= Min loop if Debug then Dump_Error ("Non-greedy repeat, N=" & Min'Img); Dump_Error ("Do we still match Next if we stop here?"); end if; -- If the next character matches if Recurse_Match (Next, 1) then return True; end if; Input_Pos := Save + Min; -- Could not or did not match -- move forward if Repeat (Operand_Code, 1) /= 0 then Min := Min + 1; else if Debug then Dump_Error ("Non-greedy repeat failed..."); end if; return False; end if; end loop; end if; return False; -- Greedy operators else No := Repeat (Operand_Code, Max); if Debug and then No < Min then Dump_Error ("failed... matched" & No'Img & " times"); end if; -- ??? Perl has some special code here in case the next -- instruction is of type EOL, since $ and \Z can match before -- *and* after newline at the end. -- ??? Perl has some special code here in case (paren) is True -- Else, if we don't have any parenthesis while No >= Min loop if not Next_Char_Known or else (Input_Pos <= Last_In_Data and then Data (Input_Pos) = Next_Char) then if Match (Next) then return True; end if; end if; -- Could not or did not work, we back up No := No - 1; Input_Pos := Save + No; end loop; return False; end if; end Match_Simple_Operator; ------------------ -- Match_Whilem -- ------------------ -- This is really hard to understand, because after we match what we -- are trying to match, we must make sure the rest of the REx is going -- to match for sure, and to do that we have to go back UP the parse -- tree by recursing ever deeper. And if it fails, we have to reset -- our parent's current state that we can try again after backing off. function Match_Whilem return Boolean is Cc : constant Current_Curly_Access := Current_Curly; N : constant Natural := Cc.Cur + 1; Ln : Natural := 0; Lastloc : constant Natural := Cc.Lastloc; -- Detection of 0-len begin -- If degenerate scan matches "", assume scan done if Input_Pos = Cc.Lastloc and then N >= Cc.Min then -- Temporarily restore the old context, and check that we -- match was comes after CURLYX. Current_Curly := Cc.Old_Cc; if Current_Curly /= null then Ln := Current_Curly.Cur; end if; if Match (Cc.Next) then return True; end if; if Current_Curly /= null then Current_Curly.Cur := Ln; end if; Current_Curly := Cc; return False; end if; -- First, just match a string of min scans if N < Cc.Min then Cc.Cur := N; Cc.Lastloc := Input_Pos; if Debug then Dump_Error ("Tests that we match at least" & Cc.Min'Img & " N=" & N'Img); end if; if Match (Cc.Scan) then return True; end if; Cc.Cur := N - 1; Cc.Lastloc := Lastloc; if Debug then Dump_Error ("failed..."); end if; return False; end if; -- Prefer next over scan for minimal matching if not Cc.Greedy then Current_Curly := Cc.Old_Cc; if Current_Curly /= null then Ln := Current_Curly.Cur; end if; if Recurse_Match (Cc.Next, Cc.Paren_Floor) then return True; end if; if Current_Curly /= null then Current_Curly.Cur := Ln; end if; Current_Curly := Cc; -- Maximum greed exceeded ? if N >= Cc.Max then if Debug then Dump_Error ("failed..."); end if; return False; end if; -- Try scanning more and see if it helps Cc.Cur := N; Cc.Lastloc := Input_Pos; if Debug then Dump_Error ("Next failed, what about Current?"); end if; if Recurse_Match (Cc.Scan, Cc.Paren_Floor) then return True; end if; Cc.Cur := N - 1; Cc.Lastloc := Lastloc; return False; end if; -- Prefer scan over next for maximal matching if N < Cc.Max then -- more greed allowed ? Cc.Cur := N; Cc.Lastloc := Input_Pos; if Debug then Dump_Error ("Recurse at current position"); end if; if Recurse_Match (Cc.Scan, Cc.Paren_Floor) then return True; end if; end if; -- Failed deeper matches of scan, so see if this one works Current_Curly := Cc.Old_Cc; if Current_Curly /= null then Ln := Current_Curly.Cur; end if; if Debug then Dump_Error ("Failed matching for later positions"); end if; if Match (Cc.Next) then return True; end if; if Current_Curly /= null then Current_Curly.Cur := Ln; end if; Current_Curly := Cc; Cc.Cur := N - 1; Cc.Lastloc := Lastloc; if Debug then Dump_Error ("failed..."); end if; return False; end Match_Whilem; ------------ -- Repeat -- ------------ function Repeat (IP : Pointer; Max : Natural := Natural'Last) return Natural is Scan : Natural := Input_Pos; Last : Natural; Op : constant Opcode := Opcode'Val (Character'Pos (Program (IP))); Count : Natural; C : Character; Is_First : Boolean := True; Bitmap : Character_Class; begin if Max = Natural'Last or else Scan + Max - 1 > Last_In_Data then Last := Last_In_Data; else Last := Scan + Max - 1; end if; case Op is when ANY => while Scan <= Last and then Data (Scan) /= ASCII.LF loop Scan := Scan + 1; end loop; when SANY => Scan := Last + 1; when EXACT => -- The string has only one character if Repeat was called C := Program (String_Operand (IP)); while Scan <= Last and then C = Data (Scan) loop Scan := Scan + 1; end loop; when EXACTF => -- The string has only one character if Repeat was called C := Program (String_Operand (IP)); while Scan <= Last and then To_Lower (C) = Data (Scan) loop Scan := Scan + 1; end loop; when ANYOF => if Is_First then Bitmap_Operand (Program, IP, Bitmap); Is_First := False; end if; while Scan <= Last and then Get_From_Class (Bitmap, Data (Scan)) loop Scan := Scan + 1; end loop; when ALNUM => while Scan <= Last and then Is_Alnum (Data (Scan)) loop Scan := Scan + 1; end loop; when NALNUM => while Scan <= Last and then not Is_Alnum (Data (Scan)) loop Scan := Scan + 1; end loop; when SPACE => while Scan <= Last and then Is_White_Space (Data (Scan)) loop Scan := Scan + 1; end loop; when NSPACE => while Scan <= Last and then not Is_White_Space (Data (Scan)) loop Scan := Scan + 1; end loop; when DIGIT => while Scan <= Last and then Is_Digit (Data (Scan)) loop Scan := Scan + 1; end loop; when NDIGIT => while Scan <= Last and then not Is_Digit (Data (Scan)) loop Scan := Scan + 1; end loop; when others => raise Program_Error; end case; Count := Scan - Input_Pos; Input_Pos := Scan; return Count; end Repeat; --------- -- Try -- --------- function Try (Pos : Positive) return Boolean is begin Input_Pos := Pos; Last_Paren := 0; Matches_Full := (others => No_Match); if Match (Program_First) then Matches_Full (0) := (Pos, Input_Pos - 1); return True; end if; return False; end Try; -- Start of processing for Match begin -- Do we have the regexp Never_Match? if Self.Size = 0 then Matches := (others => No_Match); return; end if; -- If there is a "must appear" string, look for it if Self.Must_Have_Length > 0 then declare First : constant Character := Program (Self.Must_Have); Must_First : constant Pointer := Self.Must_Have; Must_Last : constant Pointer := Must_First + Pointer (Self.Must_Have_Length - 1); Next_Try : Natural := Index (First_In_Data, First); begin while Next_Try /= 0 and then Data (Next_Try .. Next_Try + Self.Must_Have_Length - 1) = String (Program (Must_First .. Must_Last)) loop Next_Try := Index (Next_Try + 1, First); end loop; if Next_Try = 0 then Matches := (others => No_Match); return; -- Not present end if; end; end if; -- Mark beginning of line for ^ BOL_Pos := Data'First; -- Simplest case first: an anchored match need be tried only once if Self.Anchored and then (Self.Flags and Multiple_Lines) = 0 then Matched := Try (First_In_Data); elsif Self.Anchored then declare Next_Try : Natural := First_In_Data; begin -- Test the first position in the buffer Matched := Try (Next_Try); -- Else only test after newlines if not Matched then while Next_Try <= Last_In_Data loop while Next_Try <= Last_In_Data and then Data (Next_Try) /= ASCII.LF loop Next_Try := Next_Try + 1; end loop; Next_Try := Next_Try + 1; if Next_Try <= Last_In_Data then Matched := Try (Next_Try); exit when Matched; end if; end loop; end if; end; elsif Self.First /= ASCII.NUL then -- We know what char it must start with declare Next_Try : Natural := Index (First_In_Data, Self.First); begin while Next_Try /= 0 loop Matched := Try (Next_Try); exit when Matched; Next_Try := Index (Next_Try + 1, Self.First); end loop; end; else -- Messy cases: try all locations (including for the empty string) Matched := Try (First_In_Data); if not Matched then for S in First_In_Data + 1 .. Last_In_Data loop Matched := Try (S); exit when Matched; end loop; end if; end if; -- Matched has its value for J in Last_Paren + 1 .. Matches'Last loop Matches_Full (J) := No_Match; end loop; Matches := Matches_Full (Matches'Range); end Match; ----------- -- Match -- ----------- function Match (Self : Pattern_Matcher; Data : String; Data_First : Integer := -1; Data_Last : Positive := Positive'Last) return Natural is Matches : Match_Array (0 .. 0); begin Match (Self, Data, Matches, Data_First, Data_Last); if Matches (0) = No_Match then return Data'First - 1; else return Matches (0).First; end if; end Match; function Match (Self : Pattern_Matcher; Data : String; Data_First : Integer := -1; Data_Last : Positive := Positive'Last) return Boolean is Matches : Match_Array (0 .. 0); begin Match (Self, Data, Matches, Data_First, Data_Last); return Matches (0).First >= Data'First; end Match; procedure Match (Expression : String; Data : String; Matches : out Match_Array; Size : Program_Size := Auto_Size; Data_First : Integer := -1; Data_Last : Positive := Positive'Last) is PM : Pattern_Matcher (Size); Finalize_Size : Program_Size; pragma Unreferenced (Finalize_Size); begin if Size = 0 then Match (Compile (Expression), Data, Matches, Data_First, Data_Last); else Compile (PM, Expression, Finalize_Size); Match (PM, Data, Matches, Data_First, Data_Last); end if; end Match; ----------- -- Match -- ----------- function Match (Expression : String; Data : String; Size : Program_Size := Auto_Size; Data_First : Integer := -1; Data_Last : Positive := Positive'Last) return Natural is PM : Pattern_Matcher (Size); Final_Size : Program_Size; pragma Unreferenced (Final_Size); begin if Size = 0 then return Match (Compile (Expression), Data, Data_First, Data_Last); else Compile (PM, Expression, Final_Size); return Match (PM, Data, Data_First, Data_Last); end if; end Match; ----------- -- Match -- ----------- function Match (Expression : String; Data : String; Size : Program_Size := Auto_Size; Data_First : Integer := -1; Data_Last : Positive := Positive'Last) return Boolean is Matches : Match_Array (0 .. 0); PM : Pattern_Matcher (Size); Final_Size : Program_Size; pragma Unreferenced (Final_Size); begin if Size = 0 then Match (Compile (Expression), Data, Matches, Data_First, Data_Last); else Compile (PM, Expression, Final_Size); Match (PM, Data, Matches, Data_First, Data_Last); end if; return Matches (0).First >= Data'First; end Match; ------------- -- Operand -- ------------- function Operand (P : Pointer) return Pointer is begin return P + Next_Pointer_Bytes; end Operand; -------------- -- Optimize -- -------------- procedure Optimize (Self : in out Pattern_Matcher) is Scan : Pointer; Program : Program_Data renames Self.Program; begin -- Start with safe defaults (no optimization): -- * No known first character of match -- * Does not necessarily start at beginning of line -- * No string known that has to appear in data Self.First := ASCII.NUL; Self.Anchored := False; Self.Must_Have := Program'Last + 1; Self.Must_Have_Length := 0; Scan := Program_First; -- First instruction (can be anything) if Program (Scan) = EXACT then Self.First := Program (String_Operand (Scan)); elsif Program (Scan) = BOL or else Program (Scan) = SBOL or else Program (Scan) = MBOL then Self.Anchored := True; end if; end Optimize; ----------------- -- Paren_Count -- ----------------- function Paren_Count (Regexp : Pattern_Matcher) return Match_Count is begin return Regexp.Paren_Count; end Paren_Count; ----------- -- Quote -- ----------- function Quote (Str : String) return String is S : String (1 .. Str'Length * 2); Last : Natural := 0; begin for J in Str'Range loop case Str (J) is when '^' | '$' | '|' | '*' | '+' | '?' | '{' | '}' | '[' | ']' | '(' | ')' | '\' | '.' => S (Last + 1) := '\'; S (Last + 2) := Str (J); Last := Last + 2; when others => S (Last + 1) := Str (J); Last := Last + 1; end case; end loop; return S (1 .. Last); end Quote; ------------------ -- Read_Natural -- ------------------ function Read_Natural (Program : Program_Data; IP : Pointer) return Natural is begin return Character'Pos (Program (IP)) + 256 * Character'Pos (Program (IP + 1)); end Read_Natural; ----------------- -- Reset_Class -- ----------------- procedure Reset_Class (Bitmap : out Character_Class) is begin Bitmap := (others => 0); end Reset_Class; ------------------ -- Set_In_Class -- ------------------ procedure Set_In_Class (Bitmap : in out Character_Class; C : Character) is Value : constant Class_Byte := Character'Pos (C); begin Bitmap (Value / 8) := Bitmap (Value / 8) or Bit_Conversion (Value mod 8); end Set_In_Class; ------------------- -- String_Length -- ------------------- function String_Length (Program : Program_Data; P : Pointer) return Program_Size is begin pragma Assert (Program (P) = EXACT or else Program (P) = EXACTF); return Character'Pos (Program (P + Next_Pointer_Bytes)); end String_Length; -------------------- -- String_Operand -- -------------------- function String_Operand (P : Pointer) return Pointer is begin return P + 4; end String_Operand; end System.Regpat;
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