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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) 1999-2021, 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;
Capturing : Boolean;
Flags : out Expression_Flags;
IP : out Pointer);
-- Parse regular expression, i.e. main body or parenthesized thing.
-- Caller must absorb opening parenthesis. Capturing should be set to
-- True when we have an open parenthesis from which we want the user
-- to extra text.
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;
Capturing : 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 and then Capturing 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
if Capturing then
Ender := Emit_Node (CLOSE);
Emit (Character'Val (Par_No));
Link_Tail (IP, Ender);
else
-- Need to keep looking after the closing parenthesis
Ender := Emit_Ptr;
end if;
else
Ender := Emit_Node (EOP);
Link_Tail (IP, Ender);
end if;
if Have_Branch and then Emit_Ptr <= PM.Size + 1 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
if Parse_Pos <= Parse_End - 1
and then Expression (Parse_Pos) = '?'
and then Expression (Parse_Pos + 1) = ':'
then
Parse_Pos := Parse_Pos + 2;
-- Non-capturing parenthesis
Parse (True, False, New_Flags, IP);
else
-- Capturing parenthesis
Parse (True, True, New_Flags, IP);
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;
if IP = 0 then
return;
end if;
end if;
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;
In_Range := True;
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
Expr_Flags := Worst_Expression; -- Ensure Expr_Flags is initialized
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;
Parse_Pos := Parse_Pos + 1;
exit Parse_Loop when Parse_Pos > Parse_End
or else Emit_Ptr - Length_Ptr = 254;
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
or else 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, 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 =>
-- A combination of MEOL and SEOL
if (Self.Flags and Multiple_Lines) = 0 then
-- Single line mode
exit State_Machine when Input_Pos <= Data'Last;
elsif Input_Pos <= Last_In_Data then
exit State_Machine when Data (Input_Pos) /= ASCII.LF;
else
exit State_Machine when Last_In_Data /= Data'Last;
end if;
when MEOL =>
if Input_Pos <= Last_In_Data then
exit State_Machine when Data (Input_Pos) /= ASCII.LF;
else
exit State_Machine when Last_In_Data /= Data'Last;
end if;
when SEOL =>
-- If there is a character before Data'Last (even if
-- Last_In_Data stops before then), we can't have the
-- end of the line.
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;
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 =>
Bitmap_Operand (Program, IP, Bitmap);
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 (modulo casing) it must start with
if (Self.Flags and Case_Insensitive) = 0
or else Self.First not in 'a' .. 'z'
then
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
declare
Uc_First : constant Character := To_Upper (Self.First);
function Case_Insensitive_Index
(Start : Positive) return Natural;
-- Search for both Self.First and To_Upper (Self.First).
-- If both are nonzero, return the smaller one; if exactly
-- one is nonzero, return it; if both are zero, return zero.
---------------------------
-- Case_Insenstive_Index --
---------------------------
function Case_Insensitive_Index
(Start : Positive) return Natural
is
Lc_Index : constant Natural := Index (Start, Self.First);
Uc_Index : constant Natural := Index (Start, Uc_First);
begin
if Lc_Index = 0 then
return Uc_Index;
elsif Uc_Index = 0 then
return Lc_Index;
else
return Natural'Min (Lc_Index, Uc_Index);
end if;
end Case_Insensitive_Index;
Next_Try : Natural := Case_Insensitive_Index (First_In_Data);
begin
while Next_Try /= 0 loop
Matched := Try (Next_Try);
exit when Matched;
Next_Try := Case_Insensitive_Index (Next_Try + 1);
end loop;
end;
end if;
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) = EXACTF then
Self.First := To_Lower (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 --
-----------------