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@@ -0,0 +1,539 @@ +/* dfa.h - declarations for GNU deterministic regexp compiler + Copyright (C) 1988 Free Software Foundation, Inc. + Written June, 1988 by Mike Haertel + + NO WARRANTY + + BECAUSE THIS PROGRAM IS LICENSED FREE OF CHARGE, WE PROVIDE ABSOLUTELY +NO WARRANTY, TO THE EXTENT PERMITTED BY APPLICABLE STATE LAW. EXCEPT +WHEN OTHERWISE STATED IN WRITING, FREE SOFTWARE FOUNDATION, INC, +RICHARD M. STALLMAN AND/OR OTHER PARTIES PROVIDE THIS PROGRAM "AS IS" +WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, +BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND +FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY +AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE +DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR +CORRECTION. + + IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW WILL RICHARD M. +STALLMAN, THE FREE SOFTWARE FOUNDATION, INC., AND/OR ANY OTHER PARTY +WHO MAY MODIFY AND REDISTRIBUTE THIS PROGRAM AS PERMITTED BELOW, BE +LIABLE TO YOU FOR DAMAGES, INCLUDING ANY LOST PROFITS, LOST MONIES, OR +OTHER SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE +USE OR INABILITY TO USE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR +DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY THIRD PARTIES OR +A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS) THIS +PROGRAM, EVEN IF YOU HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH +DAMAGES, OR FOR ANY CLAIM BY ANY OTHER PARTY. + + GENERAL PUBLIC LICENSE TO COPY + + 1. You may copy and distribute verbatim copies of this source file +as you receive it, in any medium, provided that you conspicuously and +appropriately publish on each copy a valid copyright notice "Copyright + (C) 1988 Free Software Foundation, Inc."; and include following the +copyright notice a verbatim copy of the above disclaimer of warranty +and of this License. You may charge a distribution fee for the +physical act of transferring a copy. + + 2. You may modify your copy or copies of this source file or +any portion of it, and copy and distribute such modifications under +the terms of Paragraph 1 above, provided that you also do the following: + + a) cause the modified files to carry prominent notices stating + that you changed the files and the date of any change; and + + b) cause the whole of any work that you distribute or publish, + that in whole or in part contains or is a derivative of this + program or any part thereof, to be licensed at no charge to all + third parties on terms identical to those contained in this + License Agreement (except that you may choose to grant more extensive + warranty protection to some or all third parties, at your option). + + c) You may charge a distribution fee for the physical act of + transferring a copy, and you may at your option offer warranty + protection in exchange for a fee. + +Mere aggregation of another unrelated program with this program (or its +derivative) on a volume of a storage or distribution medium does not bring +the other program under the scope of these terms. + + 3. You may copy and distribute this program or any portion of it in +compiled, executable or object code form under the terms of Paragraphs +1 and 2 above provided that you do the following: + + a) accompany it with the complete corresponding machine-readable + source code, which must be distributed under the terms of + Paragraphs 1 and 2 above; or, + + b) accompany it with a written offer, valid for at least three + years, to give any third party free (except for a nominal + shipping charge) a complete machine-readable copy of the + corresponding source code, to be distributed under the terms of + Paragraphs 1 and 2 above; or, + + c) accompany it with the information you received as to where the + corresponding source code may be obtained. (This alternative is + allowed only for noncommercial distribution and only if you + received the program in object code or executable form alone.) + +For an executable file, complete source code means all the source code for +all modules it contains; but, as a special exception, it need not include +source code for modules which are standard libraries that accompany the +operating system on which the executable file runs. + + 4. You may not copy, sublicense, distribute or transfer this program +except as expressly provided under this License Agreement. Any attempt +otherwise to copy, sublicense, distribute or transfer this program is void and +your rights to use the program under this License agreement shall be +automatically terminated. However, parties who have received computer +software programs from you with this License Agreement will not have +their licenses terminated so long as such parties remain in full compliance. + + 5. If you wish to incorporate parts of this program into other free +programs whose distribution conditions are different, write to the Free +Software Foundation at 675 Mass Ave, Cambridge, MA 02139. We have not yet +worked out a simple rule that can be stated here, but we will often permit +this. We will be guided by the two goals of preserving the free status of +all derivatives our free software and of promoting the sharing and reuse of +software. + + +In other words, you are welcome to use, share and improve this program. +You are forbidden to forbid anyone else to use, share and improve +what you give them. Help stamp out software-hoarding! */ + +#ifdef __STDC__ + +#ifdef SOMEDAY +#define ISALNUM(c) isalnum(c) +#define ISALPHA(c) isalpha(c) +#define ISUPPER(c) isupper(c) +#else +#define ISALNUM(c) (isascii(c) && isalnum(c)) +#define ISALPHA(c) (isascii(c) && isalpha(c)) +#define ISUPPER(c) (isascii(c) && isupper(c)) +#endif + +#else /* ! __STDC__ */ + +#define const + +#define ISALNUM(c) (isascii(c) && isalnum(c)) +#define ISALPHA(c) (isascii(c) && isalpha(c)) +#define ISUPPER(c) (isascii(c) && isupper(c)) + +#endif /* ! __STDC__ */ + +/* 1 means plain parentheses serve as grouping, and backslash + parentheses are needed for literal searching. + 0 means backslash-parentheses are grouping, and plain parentheses + are for literal searching. */ +#define RE_NO_BK_PARENS 1 + +/* 1 means plain | serves as the "or"-operator, and \| is a literal. + 0 means \| serves as the "or"-operator, and | is a literal. */ +#define RE_NO_BK_VBAR (1 << 1) + +/* 0 means plain + or ? serves as an operator, and \+, \? are literals. + 1 means \+, \? are operators and plain +, ? are literals. */ +#define RE_BK_PLUS_QM (1 << 2) + +/* 1 means | binds tighter than ^ or $. + 0 means the contrary. */ +#define RE_TIGHT_VBAR (1 << 3) + +/* 1 means treat \n as an _OR operator + 0 means treat it as a normal character */ +#define RE_NEWLINE_OR (1 << 4) + +/* 0 means that a special characters (such as *, ^, and $) always have + their special meaning regardless of the surrounding context. + 1 means that special characters may act as normal characters in some + contexts. Specifically, this applies to: + ^ - only special at the beginning, or after ( or | + $ - only special at the end, or before ) or | + *, +, ? - only special when not after the beginning, (, or | */ +#define RE_CONTEXT_INDEP_OPS (1 << 5) + +/* 1 means that \ in a character class escapes the next character (typically + a hyphen. It also is overloaded to mean that hyphen at the end of the range + is allowable and means that the hyphen is to be taken literally. */ +#define RE_AWK_CLASS_HACK (1 << 6) + +/* Now define combinations of bits for the standard possibilities. */ +#ifdef notdef +#define RE_SYNTAX_AWK (RE_NO_BK_PARENS | RE_NO_BK_VBAR | RE_CONTEXT_INDEP_OPS) +#define RE_SYNTAX_EGREP (RE_SYNTAX_AWK | RE_NEWLINE_OR) +#define RE_SYNTAX_GREP (RE_BK_PLUS_QM | RE_NEWLINE_OR) +#define RE_SYNTAX_EMACS 0 +#endif + +/* The NULL pointer. */ +#ifndef NULL +#define NULL 0 +#endif + +/* Number of bits in an unsigned char. */ +#define CHARBITS 8 + +/* First integer value that is greater than any character code. */ +#define _NOTCHAR (1 << CHARBITS) + +/* INTBITS need not be exact, just a lower bound. */ +#define INTBITS (CHARBITS * sizeof (int)) + +/* Number of ints required to hold a bit for every character. */ +#define _CHARSET_INTS ((_NOTCHAR + INTBITS - 1) / INTBITS) + +/* Sets of unsigned characters are stored as bit vectors in arrays of ints. */ +typedef int _charset[_CHARSET_INTS]; + +/* The regexp is parsed into an array of tokens in postfix form. Some tokens + are operators and others are terminal symbols. Most (but not all) of these + codes are returned by the lexical analyzer. */ +#ifdef __STDC__ + +typedef enum +{ + _END = -1, /* _END is a terminal symbol that matches the + end of input; any value of _END or less in + the parse tree is such a symbol. Accepting + states of the DFA are those that would have + a transition on _END. */ + + /* Ordinary character values are terminal symbols that match themselves. */ + + _EMPTY = _NOTCHAR, /* _EMPTY is a terminal symbol that matches + the empty string. */ + + _BACKREF, /* _BACKREF is generated by \<digit>; it + it not completely handled. If the scanner + detects a transition on backref, it returns + a kind of "semi-success" indicating that + the match will have to be verified with + a backtracking matcher. */ + + _BEGLINE, /* _BEGLINE is a terminal symbol that matches + the empty string if it is at the beginning + of a line. */ + + _ALLBEGLINE, /* _ALLBEGLINE is a terminal symbol that + matches the empty string if it is at the + beginning of a line; _ALLBEGLINE applies + to the entire regexp and can only occur + as the first token thereof. _ALLBEGLINE + never appears in the parse tree; a _BEGLINE + is prepended with _CAT to the entire + regexp instead. */ + + _ENDLINE, /* _ENDLINE is a terminal symbol that matches + the empty string if it is at the end of + a line. */ + + _ALLENDLINE, /* _ALLENDLINE is to _ENDLINE as _ALLBEGLINE + is to _BEGLINE. */ + + _BEGWORD, /* _BEGWORD is a terminal symbol that matches + the empty string if it is at the beginning + of a word. */ + + _ENDWORD, /* _ENDWORD is a terminal symbol that matches + the empty string if it is at the end of + a word. */ + + _LIMWORD, /* _LIMWORD is a terminal symbol that matches + the empty string if it is at the beginning + or the end of a word. */ + + _NOTLIMWORD, /* _NOTLIMWORD is a terminal symbol that + matches the empty string if it is not at + the beginning or end of a word. */ + + _QMARK, /* _QMARK is an operator of one argument that + matches zero or one occurences of its + argument. */ + + _STAR, /* _STAR is an operator of one argument that + matches the Kleene closure (zero or more + occurrences) of its argument. */ + + _PLUS, /* _PLUS is an operator of one argument that + matches the positive closure (one or more + occurrences) of its argument. */ + + _CAT, /* _CAT is an operator of two arguments that + matches the concatenation of its + arguments. _CAT is never returned by the + lexical analyzer. */ + + _OR, /* _OR is an operator of two arguments that + matches either of its arguments. */ + + _LPAREN, /* _LPAREN never appears in the parse tree, + it is only a lexeme. */ + + _RPAREN, /* _RPAREN never appears in the parse tree. */ + + _SET /* _SET and (and any value greater) is a + terminal symbol that matches any of a + class of characters. */ +} _token; + +#else /* ! __STDC__ */ + +typedef short _token; + +#define _END -1 +#define _EMPTY _NOTCHAR +#define _BACKREF (_EMPTY + 1) +#define _BEGLINE (_EMPTY + 2) +#define _ALLBEGLINE (_EMPTY + 3) +#define _ENDLINE (_EMPTY + 4) +#define _ALLENDLINE (_EMPTY + 5) +#define _BEGWORD (_EMPTY + 6) +#define _ENDWORD (_EMPTY + 7) +#define _LIMWORD (_EMPTY + 8) +#define _NOTLIMWORD (_EMPTY + 9) +#define _QMARK (_EMPTY + 10) +#define _STAR (_EMPTY + 11) +#define _PLUS (_EMPTY + 12) +#define _CAT (_EMPTY + 13) +#define _OR (_EMPTY + 14) +#define _LPAREN (_EMPTY + 15) +#define _RPAREN (_EMPTY + 16) +#define _SET (_EMPTY + 17) + +#endif /* ! __STDC__ */ + +/* Sets are stored in an array in the compiled regexp; the index of the + array corresponding to a given set token is given by _SET_INDEX(t). */ +#define _SET_INDEX(t) ((t) - _SET) + +/* Sometimes characters can only be matched depending on the surrounding + context. Such context decisions depend on what the previous character + was, and the value of the current (lookahead) character. Context + dependent constraints are encoded as 8 bit integers. Each bit that + is set indicates that the constraint succeeds in the corresponding + context. + + bit 7 - previous and current are newlines + bit 6 - previous was newline, current isn't + bit 5 - previous wasn't newline, current is + bit 4 - neither previous nor current is a newline + bit 3 - previous and current are word-constituents + bit 2 - previous was word-constituent, current isn't + bit 1 - previous wasn't word-constituent, current is + bit 0 - neither previous nor current is word-constituent + + Word-constituent characters are those that satisfy isalnum(). + + The macro _SUCCEEDS_IN_CONTEXT determines whether a a given constraint + succeeds in a particular context. Prevn is true if the previous character + was a newline, currn is true if the lookahead character is a newline. + Prevl and currl similarly depend upon whether the previous and current + characters are word-constituent letters. */ +#define _MATCHES_NEWLINE_CONTEXT(constraint, prevn, currn) \ + ((constraint) & 1 << ((prevn) ? 2 : 0) + ((currn) ? 1 : 0) + 4) +#define _MATCHES_LETTER_CONTEXT(constraint, prevl, currl) \ + ((constraint) & 1 << ((prevl) ? 2 : 0) + ((currl) ? 1 : 0)) +#define _SUCCEEDS_IN_CONTEXT(constraint, prevn, currn, prevl, currl) \ + (_MATCHES_NEWLINE_CONTEXT(constraint, prevn, currn) \ + && _MATCHES_LETTER_CONTEXT(constraint, prevl, currl)) + +/* The following macros give information about what a constraint depends on. */ +#define _PREV_NEWLINE_DEPENDENT(constraint) \ + (((constraint) & 0xc0) >> 2 != ((constraint) & 0x30)) +#define _PREV_LETTER_DEPENDENT(constraint) \ + (((constraint) & 0x0c) >> 2 != ((constraint) & 0x03)) + +/* Tokens that match the empty string subject to some constraint actually + work by applying that constraint to determine what may follow them, + taking into account what has gone before. The following values are + the constraints corresponding to the special tokens previously defined. */ +#define _NO_CONSTRAINT 0xff +#define _BEGLINE_CONSTRAINT 0xcf +#define _ENDLINE_CONSTRAINT 0xaf +#define _BEGWORD_CONSTRAINT 0xf2 +#define _ENDWORD_CONSTRAINT 0xf4 +#define _LIMWORD_CONSTRAINT 0xf6 +#define _NOTLIMWORD_CONSTRAINT 0xf9 + +/* States of the recognizer correspond to sets of positions in the parse + tree, together with the constraints under which they may be matched. + So a position is encoded as an index into the parse tree together with + a constraint. */ +typedef struct +{ + unsigned index; /* Index into the parse array. */ + unsigned constraint; /* Constraint for matching this position. */ +} _position; + +/* Sets of positions are stored as arrays. */ +typedef struct +{ + _position *elems; /* Elements of this position set. */ + int nelem; /* Number of elements in this set. */ +} _position_set; + +/* A state of the regexp consists of a set of positions, some flags, + and the token value of the lowest-numbered position of the state that + contains an _END token. */ +typedef struct +{ + int hash; /* Hash of the positions of this state. */ + _position_set elems; /* Positions this state could match. */ + char newline; /* True if previous state matched newline. */ + char letter; /* True if previous state matched a letter. */ + char backref; /* True if this state matches a \<digit>. */ + unsigned char constraint; /* Constraint for this state to accept. */ + int first_end; /* Token value of the first _END in elems. */ +} _dfa_state; + +/* If an r.e. is at most MUST_MAX characters long, we look for a string which + must appear in it; whatever's found is dropped into the struct reg. */ + +#define MUST_MAX 50 + +/* A compiled regular expression. */ +struct regexp +{ + /* Stuff built by the scanner. */ + _charset *charsets; /* Array of character sets for _SET tokens. */ + int cindex; /* Index for adding new charsets. */ + int calloc; /* Number of charsets currently allocated. */ + + /* Stuff built by the parser. */ + _token *tokens; /* Postfix parse array. */ + int tindex; /* Index for adding new tokens. */ + int talloc; /* Number of tokens currently allocated. */ + int depth; /* Depth required of an evaluation stack + used for depth-first traversal of the + parse tree. */ + int nleaves; /* Number of leaves on the parse tree. */ + int nregexps; /* Count of parallel regexps being built + with regparse(). */ + + /* Stuff owned by the state builder. */ + _dfa_state *states; /* States of the regexp. */ + int sindex; /* Index for adding new states. */ + int salloc; /* Number of states currently allocated. */ + + /* Stuff built by the structure analyzer. */ + _position_set *follows; /* Array of follow sets, indexed by position + index. The follow of a position is the set + of positions containing characters that + could conceivably follow a character + matching the given position in a string + matching the regexp. Allocated to the + maximum possible position index. */ + int searchflag; /* True if we are supposed to build a searching + as opposed to an exact matcher. A searching + matcher finds the first and shortest string + matching a regexp anywhere in the buffer, + whereas an exact matcher finds the longest + string matching, but anchored to the + beginning of the buffer. */ + + /* Stuff owned by the executor. */ + int tralloc; /* Number of transition tables that have + slots so far. */ + int trcount; /* Number of transition tables that have + actually been built. */ + int **trans; /* Transition tables for states that can + never accept. If the transitions for a + state have not yet been computed, or the + state could possibly accept, its entry in + this table is NULL. */ + int **realtrans; /* Trans always points to realtrans + 1; this + is so trans[-1] can contain NULL. */ + int **fails; /* Transition tables after failing to accept + on a state that potentially could do so. */ + int *success; /* Table of acceptance conditions used in + regexecute and computed in build_state. */ + int *newlines; /* Transitions on newlines. The entry for a + newline in any transition table is always + -1 so we can count lines without wasting + too many cycles. The transition for a + newline is stored separately and handled + as a special case. Newline is also used + as a sentinel at the end of the buffer. */ + char must[MUST_MAX]; + int mustn; +}; + +/* Some macros for user access to regexp internals. */ + +/* ACCEPTING returns true if s could possibly be an accepting state of r. */ +#define ACCEPTING(s, r) ((r).states[s].constraint) + +/* ACCEPTS_IN_CONTEXT returns true if the given state accepts in the + specified context. */ +#define ACCEPTS_IN_CONTEXT(prevn, currn, prevl, currl, state, reg) \ + _SUCCEEDS_IN_CONTEXT((reg).states[state].constraint, \ + prevn, currn, prevl, currl) + +/* FIRST_MATCHING_REGEXP returns the index number of the first of parallel + regexps that a given state could accept. Parallel regexps are numbered + starting at 1. */ +#define FIRST_MATCHING_REGEXP(state, reg) (-(reg).states[state].first_end) + +/* Entry points. */ + +#ifdef __STDC__ + +/* Regsyntax() takes two arguments; the first sets the syntax bits described + earlier in this file, and the second sets the case-folding flag. */ +extern void regsyntax(int, int); + +/* Compile the given string of the given length into the given struct regexp. + Final argument is a flag specifying whether to build a searching or an + exact matcher. */ +extern void regcompile(const char *, size_t, struct regexp *, int); + +/* Execute the given struct regexp on the buffer of characters. The + first char * points to the beginning, and the second points to the + first character after the end of the buffer, which must be a writable + place so a sentinel end-of-buffer marker can be stored there. The + second-to-last argument is a flag telling whether to allow newlines to + be part of a string matching the regexp. The next-to-last argument, + if non-NULL, points to a place to increment every time we see a + newline. The final argument, if non-NULL, points to a flag that will + be set if further examination by a backtracking matcher is needed in + order to verify backreferencing; otherwise the flag will be cleared. + Returns NULL if no match is found, or a pointer to the first + character after the first & shortest matching string in the buffer. */ +extern char *regexecute(struct regexp *, char *, char *, int, int *, int *); + +/* Free the storage held by the components of a struct regexp. */ +extern void regfree(struct regexp *); + +/* Entry points for people who know what they're doing. */ + +/* Initialize the components of a struct regexp. */ +extern void reginit(struct regexp *); + +/* Incrementally parse a string of given length into a struct regexp. */ +extern void regparse(const char *, size_t, struct regexp *); + +/* Analyze a parsed regexp; second argument tells whether to build a searching + or an exact matcher. */ +extern void reganalyze(struct regexp *, int); + +/* Compute, for each possible character, the transitions out of a given + state, storing them in an array of integers. */ +extern void regstate(int, struct regexp *, int []); + +/* Error handling. */ + +/* Regerror() is called by the regexp routines whenever an error occurs. It + takes a single argument, a NUL-terminated string describing the error. + The default regerror() prints the error message to stderr and exits. + The user can provide a different regfree() if so desired. */ +extern void regerror(const char *); + +#else /* ! __STDC__ */ +extern void regsyntax(), regcompile(), regfree(), reginit(), regparse(); +extern void reganalyze(), regstate(), regerror(); +extern char *regexecute(); +#endif |