1247 lines
36 KiB
C
1247 lines
36 KiB
C
/* $Source: /u/mark/src/pax/RCS/regexp.c,v $
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*
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* $Revision: 1.2 $
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*
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* regexp.c - regular expression matching
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*
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* DESCRIPTION
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*
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* Underneath the reformatting and comment blocks which were added to
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* make it consistent with the rest of the code, you will find a
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* modified version of Henry Specer's regular expression library.
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* Henry's functions were modified to provide the minimal regular
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* expression matching, as required by P1003. Henry's code was
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* copyrighted, and copy of the copyright message and restrictions
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* are provided, verbatim, below:
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*
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* Copyright (c) 1986 by University of Toronto.
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* Written by Henry Spencer. Not derived from licensed software.
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*
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* Permission is granted to anyone to use this software for any
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* purpose on any computer system, and to redistribute it freely,
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* subject to the following restrictions:
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*
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* 1. The author is not responsible for the consequences of use of
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* this software, no matter how awful, even if they arise
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* from defects in it.
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*
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* 2. The origin of this software must not be misrepresented, either
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* by explicit claim or by omission.
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*
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* 3. Altered versions must be plainly marked as such, and must not
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* be misrepresented as being the original software.
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*
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* Beware that some of this code is subtly aware of the way operator
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* precedence is structured in regular expressions. Serious changes in
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* regular-expression syntax might require a total rethink.
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*
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* AUTHORS
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*
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* Mark H. Colburn, NAPS International (mark@jhereg.mn.org)
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* Henry Spencer, University of Torronto (henry@utzoo.edu)
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*
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* Sponsored by The USENIX Association for public distribution.
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*
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* $Log: regexp.c,v $
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* Revision 1.2 89/02/12 10:05:39 mark
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* 1.2 release fixes
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*
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* Revision 1.1 88/12/23 18:02:32 mark
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* Initial revision
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*
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*/
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/* Headers */
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#include "pax.h"
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#ifndef lint
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static char *Ident = "$Id: regexp.c,v 1.2 89/02/12 10:05:39 mark Exp $";
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#endif
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/*
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* The "internal use only" fields in regexp.h are present to pass info from
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* compile to execute that permits the execute phase to run lots faster on
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* simple cases. They are:
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*
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* regstart char that must begin a match; '\0' if none obvious
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* reganch is the match anchored (at beginning-of-line only)?
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* regmust string (pointer into program) that match must include, or NULL
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* regmlen length of regmust string
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*
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* Regstart and reganch permit very fast decisions on suitable starting points
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* for a match, cutting down the work a lot. Regmust permits fast rejection
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* of lines that cannot possibly match. The regmust tests are costly enough
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* that regcomp() supplies a regmust only if the r.e. contains something
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* potentially expensive (at present, the only such thing detected is * or +
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* at the start of the r.e., which can involve a lot of backup). Regmlen is
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* supplied because the test in regexec() needs it and regcomp() is computing
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* it anyway.
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*/
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/*
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* Structure for regexp "program". This is essentially a linear encoding
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* of a nondeterministic finite-state machine (aka syntax charts or
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* "railroad normal form" in parsing technology). Each node is an opcode
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* plus a "nxt" pointer, possibly plus an operand. "Nxt" pointers of
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* all nodes except BRANCH implement concatenation; a "nxt" pointer with
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* a BRANCH on both ends of it is connecting two alternatives. (Here we
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* have one of the subtle syntax dependencies: an individual BRANCH (as
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* opposed to a collection of them) is never concatenated with anything
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* because of operator precedence.) The operand of some types of node is
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* a literal string; for others, it is a node leading into a sub-FSM. In
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* particular, the operand of a BRANCH node is the first node of the branch.
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* (NB this is *not* a tree structure: the tail of the branch connects
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* to the thing following the set of BRANCHes.) The opcodes are:
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*/
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/* definition number opnd? meaning */
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#define END 0 /* no End of program. */
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#define BOL 1 /* no Match "" at beginning of line. */
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#define EOL 2 /* no Match "" at end of line. */
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#define ANY 3 /* no Match any one character. */
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#define ANYOF 4 /* str Match any character in this string. */
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#define ANYBUT 5 /* str Match any character not in this
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* string. */
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#define BRANCH 6 /* node Match this alternative, or the
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* nxt... */
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#define BACK 7 /* no Match "", "nxt" ptr points backward. */
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#define EXACTLY 8 /* str Match this string. */
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#define NOTHING 9 /* no Match empty string. */
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#define STAR 10 /* node Match this (simple) thing 0 or more
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* times. */
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#define OPEN 20 /* no Mark this point in input as start of
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* #n. */
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/* OPEN+1 is number 1, etc. */
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#define CLOSE 30 /* no Analogous to OPEN. */
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/*
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* Opcode notes:
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*
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* BRANCH The set of branches constituting a single choice are hooked
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* together with their "nxt" pointers, since precedence prevents
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* anything being concatenated to any individual branch. The
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* "nxt" pointer of the last BRANCH in a choice points to the
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* thing following the whole choice. This is also where the
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* final "nxt" pointer of each individual branch points; each
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* branch starts with the operand node of a BRANCH node.
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*
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* BACK Normal "nxt" pointers all implicitly point forward; BACK
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* exists to make loop structures possible.
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*
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* STAR complex '*', are implemented as circular BRANCH structures
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* using BACK. Simple cases (one character per match) are
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* implemented with STAR for speed and to minimize recursive
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* plunges.
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*
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* OPEN,CLOSE ...are numbered at compile time.
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*/
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/*
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* A node is one char of opcode followed by two chars of "nxt" pointer.
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* "Nxt" pointers are stored as two 8-bit pieces, high order first. The
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* value is a positive offset from the opcode of the node containing it.
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* An operand, if any, simply follows the node. (Note that much of the
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* code generation knows about this implicit relationship.)
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*
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* Using two bytes for the "nxt" pointer is vast overkill for most things,
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* but allows patterns to get big without disasters.
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*/
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#define OP(p) (*(p))
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#define NEXT(p) (((*((p)+1)&0377)<<8) + (*((p)+2)&0377))
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#define OPERAND(p) ((p) + 3)
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/*
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* Utility definitions.
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*/
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#define FAIL(m) { regerror(m); return(NULL); }
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#define ISMULT(c) ((c) == '*')
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#define META "^$.[()|*\\"
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#ifndef CHARBITS
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#define UCHARAT(p) ((int)*(unsigned char *)(p))
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#else
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#define UCHARAT(p) ((int)*(p)&CHARBITS)
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#endif
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/*
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* Flags to be passed up and down.
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*/
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#define HASWIDTH 01 /* Known never to match null string. */
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#define SIMPLE 02 /* Simple enough to be STAR operand. */
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#define SPSTART 04 /* Starts with * */
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#define WORST 0 /* Worst case. */
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/*
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* Global work variables for regcomp().
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*/
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static char *regparse; /* Input-scan pointer. */
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static int regnpar; /* () count. */
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static char regdummy;
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static char *regcode; /* Code-emit pointer; ®dummy = don't. */
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static long regsize; /* Code size. */
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/*
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* Forward declarations for regcomp()'s friends.
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*/
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#ifndef STATIC
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#define STATIC static
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#endif
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STATIC char *reg(int, int *); /* Xn */
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STATIC char *regbranch(int *); /* Xn */
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STATIC char *regpiece(int *); /* Xn */
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STATIC char *regatom(int *); /* Xn */
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STATIC char *regnode(char); /* Xn */
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STATIC char *regnext(register char *); /* Xn */
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STATIC void regc(char); /* Xn */
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STATIC void reginsert(char, char *); /* Xn */
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STATIC void regtail(char *, char *); /* Xn */
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STATIC void regoptail(char *, char *); /* Xn */
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#ifdef STRCSPN
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STATIC size_t strcspn(const char *, const char *); /* Xn */
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#endif
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/*
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- regcomp - compile a regular expression into internal code
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*
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* We can't allocate space until we know how big the compiled form will be,
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* but we can't compile it (and thus know how big it is) until we've got a
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* place to put the code. So we cheat: we compile it twice, once with code
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* generation turned off and size counting turned on, and once "for real".
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* This also means that we don't allocate space until we are sure that the
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* thing really will compile successfully, and we never have to move the
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* code and thus invalidate pointers into it. (Note that it has to be in
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* one piece because free() must be able to free it all.)
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*
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* Beware that the optimization-preparation code in here knows about some
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* of the structure of the compiled regexp.
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*/
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regexp *regcomp(char *exp) /* Xn */
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{
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register regexp *r;
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register char *scan;
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register char *longest;
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register size_t len;
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int flags;
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if (exp == (char *)NULL)
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FAIL("NULL argument");
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/* First pass: determine size, legality. */
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regparse = exp;
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regnpar = 1;
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regsize = 0L;
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regcode = ®dummy;
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regc(MAGIC);
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if (reg(0, &flags) == (char *)NULL)
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return ((regexp *)NULL);
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/* Small enough for pointer-storage convention? */
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if (regsize >= 32767L) /* Probably could be 65535L. */
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FAIL("regexp too big");
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/* Allocate space. */
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r = (regexp *) malloc(sizeof(regexp) + (unsigned) regsize);
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if (r == (regexp *) NULL)
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FAIL("out of space");
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/* Second pass: emit code. */
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regparse = exp;
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regnpar = 1;
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regcode = r->program;
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regc(MAGIC);
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if (reg(0, &flags) == NULL)
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return ((regexp *) NULL);
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/* Dig out information for optimizations. */
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r->regstart = '\0'; /* Worst-case defaults. */
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r->reganch = 0;
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r->regmust = NULL;
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r->regmlen = 0;
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scan = r->program + 1; /* First BRANCH. */
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if (OP(regnext(scan)) == END) { /* Only one top-level choice. */
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scan = OPERAND(scan);
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/* Starting-point info. */
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if (OP(scan) == EXACTLY)
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r->regstart = *OPERAND(scan);
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else if (OP(scan) == BOL)
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r->reganch++;
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/*
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* If there's something expensive in the r.e., find the longest
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* literal string that must appear and make it the regmust. Resolve
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* ties in favor of later strings, since the regstart check works
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* with the beginning of the r.e. and avoiding duplication
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* strengthens checking. Not a strong reason, but sufficient in the
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* absence of others.
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*/
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if (flags & SPSTART) {
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longest = NULL;
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len = 0;
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for (; scan != NULL; scan = regnext(scan))
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if (OP(scan) == EXACTLY && strlen(OPERAND(scan)) >= len) {
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longest = OPERAND(scan);
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len = strlen(OPERAND(scan));
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}
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r->regmust = longest;
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r->regmlen = len;
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}
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}
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return (r);
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}
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/*
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- reg - regular expression, i.e. main body or parenthesized thing
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*
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* Caller must absorb opening parenthesis.
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*
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* Combining parenthesis handling with the base level of regular expression
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* is a trifle forced, but the need to tie the tails of the branches to what
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* follows makes it hard to avoid.
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*/
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static char *reg(int paren, int *flagp) /* Xn */
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{
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register char *ret;
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register char *br;
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register char *ender;
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register int parno;
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int flags;
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*flagp = HASWIDTH; /* Tentatively. */
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/* Make an OPEN node, if parenthesized. */
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#ifdef DF_TRACE_DEBUG
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printf("DF_TRACE_DEBUG: static char *reg() in regexp.c\n");
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#endif
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if (paren) {
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if (regnpar >= NSUBEXP)
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FAIL("too many ()");
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parno = regnpar;
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regnpar++;
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ret = regnode((char)(OPEN + parno));
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} else
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ret = (char *)NULL;
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/* Pick up the branches, linking them together. */
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br = regbranch(&flags);
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if (br == (char *)NULL)
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return ((char *)NULL);
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if (ret != (char *)NULL)
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regtail(ret, br); /* OPEN -> first. */
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else
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ret = br;
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if (!(flags & HASWIDTH))
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*flagp &= ~HASWIDTH;
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*flagp |= flags & SPSTART;
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while (*regparse == '|') {
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regparse++;
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br = regbranch(&flags);
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if (br == (char *)NULL)
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return ((char *)NULL);
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regtail(ret, br); /* BRANCH -> BRANCH. */
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if (!(flags & HASWIDTH))
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*flagp &= ~HASWIDTH;
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*flagp |= flags & SPSTART;
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}
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/* Make a closing node, and hook it on the end. */
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ender = regnode((char)((paren) ? CLOSE + parno : END));
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regtail(ret, ender);
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/* Hook the tails of the branches to the closing node. */
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for (br = ret; br != (char *)NULL; br = regnext(br))
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regoptail(br, ender);
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/* Check for proper termination. */
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if (paren && *regparse++ != ')') {
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FAIL("unmatched ()");
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} else if (!paren && *regparse != '\0') {
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if (*regparse == ')') {
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FAIL("unmatched ()");
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} else
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FAIL("junk on end");/* "Can't happen". */
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/* NOTREACHED */
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}
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return (ret);
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}
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/*
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- regbranch - one alternative of an | operator
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*
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* Implements the concatenation operator.
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*/
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static char *regbranch(int *flagp) /* Xn */
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{
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register char *ret;
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register char *chain;
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register char *latest;
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int flags;
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*flagp = WORST; /* Tentatively. */
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#ifdef DF_TRACE_DEBUG
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printf("DF_TRACE_DEBUG: static char *regbranch() in regexp.c\n");
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#endif
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ret = regnode(BRANCH);
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chain = (char *)NULL;
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while (*regparse != '\0' && *regparse != '|' && *regparse != ')') {
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latest = regpiece(&flags);
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if (latest == (char *)NULL)
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return ((char *)NULL);
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*flagp |= flags & HASWIDTH;
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if (chain == (char *)NULL) /* First piece. */
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*flagp |= flags & SPSTART;
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else
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regtail(chain, latest);
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chain = latest;
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}
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if (chain == (char *)NULL) /* Loop ran zero times. */
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regnode(NOTHING);
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return (ret);
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}
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/*
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- regpiece - something followed by possible [*]
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*
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* Note that the branching code sequence used for * is somewhat optimized:
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* they use the same NOTHING node as both the endmarker for their branch
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* list and the body of the last branch. It might seem that this node could
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* be dispensed with entirely, but the endmarker role is not redundant.
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*/
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static char *regpiece(int *flagp) /* Xn */
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{
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register char *ret;
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register char op;
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int flags;
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ret = regatom(&flags);
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if (ret == (char *)NULL)
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return ((char *)NULL);
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op = *regparse;
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if (!ISMULT(op)) {
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*flagp = flags;
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return (ret);
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}
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if (!(flags & HASWIDTH))
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FAIL("* operand could be empty");
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*flagp = (WORST | SPSTART);
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if (op == '*' && (flags & SIMPLE))
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reginsert(STAR, ret);
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else if (op == '*') {
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/* Emit x* as (x&|), where & means "self". */
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reginsert(BRANCH, ret); /* Either x */
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regoptail(ret, regnode(BACK)); /* and loop */
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regoptail(ret, ret); /* back */
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regtail(ret, regnode(BRANCH)); /* or */
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regtail(ret, regnode(NOTHING)); /* null. */
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}
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regparse++;
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if (ISMULT(*regparse))
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FAIL("nested *");
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return (ret);
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}
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/*
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- regatom - the lowest level
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*
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* Optimization: gobbles an entire sequence of ordinary characters so that
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* it can turn them into a single node, which is smaller to store and
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* faster to run. Backslashed characters are exceptions, each becoming a
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* separate node; the code is simpler that way and it's not worth fixing.
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*/
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static char *regatom(int *flagp) /* Xn */
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{
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register char *ret;
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int flags;
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*flagp = WORST; /* Tentatively. */
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switch (*regparse++) {
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case '^':
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ret = regnode(BOL);
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break;
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case '$':
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ret = regnode(EOL);
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break;
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case '.':
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ret = regnode(ANY);
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*flagp |= HASWIDTH | SIMPLE;
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break;
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case '[':{
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register int class;
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register int classend;
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if (*regparse == '^') { /* Complement of range. */
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ret = regnode(ANYBUT);
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regparse++;
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} else
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ret = regnode(ANYOF);
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if (*regparse == ']' || *regparse == '-')
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regc(*regparse++);
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while (*regparse != '\0' && *regparse != ']') {
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if (*regparse == '-') {
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regparse++;
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if (*regparse == ']' || *regparse == '\0')
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regc('-');
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else {
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class = UCHARAT(regparse - 2) + 1;
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classend = UCHARAT(regparse);
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if (class > classend + 1)
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FAIL("invalid [] range");
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for (; class <= classend; class++)
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regc((char)class);
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regparse++;
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}
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} else
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regc(*regparse++);
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}
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regc('\0');
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if (*regparse != ']')
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FAIL("unmatched []");
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regparse++;
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*flagp |= HASWIDTH | SIMPLE;
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}
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break;
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case '(':
|
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ret = reg(1, &flags);
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if (ret == (char *)NULL)
|
|
return ((char *)NULL);
|
|
*flagp |= flags & (HASWIDTH | SPSTART);
|
|
break;
|
|
case '\0':
|
|
case '|':
|
|
case ')':
|
|
FAIL("internal urp"); /* Supposed to be caught earlier. */
|
|
case '*':
|
|
FAIL("* follows nothing");
|
|
case '\\':
|
|
if (*regparse == '\0')
|
|
FAIL("trailing \\");
|
|
ret = regnode(EXACTLY);
|
|
regc(*regparse++);
|
|
regc('\0');
|
|
*flagp |= HASWIDTH | SIMPLE;
|
|
break;
|
|
default:{
|
|
register uint len; /* Xn */
|
|
register char ender;
|
|
|
|
regparse--;
|
|
len = strcspn(regparse, META);
|
|
ender = *(regparse + len);
|
|
if (len > 1 && ISMULT(ender))
|
|
len--; /* Back off clear of * operand. */
|
|
*flagp |= HASWIDTH;
|
|
if (len == 1)
|
|
*flagp |= SIMPLE;
|
|
ret = regnode(EXACTLY);
|
|
while (len > 0) {
|
|
regc(*regparse++);
|
|
len--;
|
|
}
|
|
regc('\0');
|
|
}
|
|
break;
|
|
}
|
|
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
- regnode - emit a node
|
|
*/
|
|
static char *regnode(char op) /* Xn */
|
|
{
|
|
register char *ret;
|
|
register char *ptr;
|
|
|
|
ret = regcode;
|
|
#ifdef DF_TRACE_DEBUG
|
|
printf("DF_TRACE_DEBUG: static char *regnode() in regexp.c\n");
|
|
#endif
|
|
if (ret == ®dummy) {
|
|
regsize += 3;
|
|
return (ret);
|
|
}
|
|
ptr = ret;
|
|
*ptr++ = op;
|
|
*ptr++ = '\0'; /* Null "nxt" pointer. */
|
|
*ptr++ = '\0';
|
|
regcode = ptr;
|
|
|
|
return (ret);
|
|
}
|
|
|
|
/*
|
|
- regc - emit (if appropriate) a byte of code
|
|
*/
|
|
static void regc(char b) /* Xn */
|
|
{
|
|
#ifdef DF_TRACE_DEBUG
|
|
printf("DF_TRACE_DEBUG: static void regc() in regexp.c\n");
|
|
#endif
|
|
if (regcode != ®dummy)
|
|
*regcode++ = b;
|
|
else
|
|
regsize++;
|
|
}
|
|
|
|
/*
|
|
- reginsert - insert an operator in front of already-emitted operand
|
|
*
|
|
* Means relocating the operand.
|
|
*/
|
|
static void reginsert(char op, char *opnd) /* Xn */
|
|
{
|
|
register char *src;
|
|
register char *dst;
|
|
register char *place;
|
|
|
|
#ifdef DF_TRACE_DEBUG
|
|
printf("DF_TRACE_DEBUG: static void reginsert() in regexp.c\n");
|
|
#endif
|
|
if (regcode == ®dummy) {
|
|
regsize += 3;
|
|
return;
|
|
}
|
|
src = regcode;
|
|
regcode += 3;
|
|
dst = regcode;
|
|
while (src > opnd)
|
|
*--dst = *--src;
|
|
|
|
place = opnd; /* Op node, where operand used to be. */
|
|
*place++ = op;
|
|
*place++ = '\0';
|
|
*place++ = '\0';
|
|
}
|
|
|
|
/*
|
|
- regtail - set the next-pointer at the end of a node chain
|
|
*/
|
|
static void regtail(char *p, char *val) /* Xn */
|
|
{
|
|
register char *scan;
|
|
register char *temp;
|
|
register int offset;
|
|
|
|
if (p == ®dummy)
|
|
return;
|
|
|
|
/* Find last node. */
|
|
scan = p;
|
|
for (;;) {
|
|
temp = regnext(scan);
|
|
if (temp == (char *)NULL)
|
|
break;
|
|
scan = temp;
|
|
}
|
|
|
|
if (OP(scan) == BACK)
|
|
offset = (int)(scan - val);
|
|
else
|
|
offset = (int)(val - scan);
|
|
*(scan + 1) = (offset >> 8) & 0377;
|
|
*(scan + 2) = offset & 0377;
|
|
}
|
|
|
|
/*
|
|
- regoptail - regtail on operand of first argument; nop if operandless
|
|
*/
|
|
static void regoptail(char *p, char *val) /* Xn */
|
|
{
|
|
/* "Operandless" and "op != BRANCH" are synonymous in practice. */
|
|
if (p == (char *)NULL || p == ®dummy || OP(p) != BRANCH)
|
|
return;
|
|
regtail(OPERAND(p), val);
|
|
}
|
|
|
|
/*
|
|
* regexec and friends
|
|
*/
|
|
|
|
/*
|
|
* Global work variables for regexec().
|
|
*/
|
|
static char *reginput; /* String-input pointer. */
|
|
static char *regbol; /* Beginning of input, for ^ check. */
|
|
static char **regstartp; /* Pointer to startp array. */
|
|
static char **regendp; /* Ditto for endp. */
|
|
|
|
/*
|
|
* Forwards.
|
|
*/
|
|
STATIC int regtry(regexp *, char *); /* Xn */
|
|
STATIC int regmatch(char *); /* Xn */
|
|
STATIC int regrepeat(char *); /* Xn */
|
|
/* Xn */
|
|
#ifdef DEBUG /* Xn */
|
|
int regnarrate = 0; /* Xn */
|
|
void regdump(regexp *); /* Xn */
|
|
STATIC char *regprop(char *); /* Xn */
|
|
#endif /* Xn */
|
|
|
|
/*
|
|
- regexec - match a regexp against a string
|
|
*/
|
|
int regexec(register regexp *prog, register char *string) /* Xn */
|
|
{
|
|
register char *s;
|
|
|
|
/* Be paranoid... */
|
|
#ifdef DF_TRACE_DEBUG
|
|
printf("DF_TRACE_DEBUG: int regexec() in regexp.c\n");
|
|
#endif
|
|
if (prog == (regexp *)NULL || string == (char *)NULL) {
|
|
regerror("NULL parameter");
|
|
return (0);
|
|
}
|
|
/* Check validity of program. */
|
|
if (UCHARAT(prog->program) != MAGIC) {
|
|
regerror("corrupted program");
|
|
return (0);
|
|
}
|
|
/* If there is a "must appear" string, look for it. */
|
|
if (prog->regmust != (char *)NULL) {
|
|
s = string;
|
|
while ((s = strchr(s, prog->regmust[0])) != (char *)NULL) {
|
|
if (strncmp(s, prog->regmust, prog->regmlen) == 0)
|
|
break; /* Found it. */
|
|
s++;
|
|
}
|
|
if (s == (char *)NULL) /* Not present. */
|
|
return (0);
|
|
}
|
|
/* Mark beginning of line for ^ . */
|
|
regbol = string;
|
|
|
|
/* Simplest case: anchored match need be tried only once. */
|
|
if (prog->reganch)
|
|
return (regtry(prog, string));
|
|
|
|
/* Messy cases: unanchored match. */
|
|
s = string;
|
|
if (prog->regstart != '\0')
|
|
/* We know what char it must start with. */
|
|
while ((s = strchr(s, prog->regstart)) != (char *)NULL) {
|
|
if (regtry(prog, s))
|
|
return (1);
|
|
s++;
|
|
} else
|
|
/* We don't -- general case. */
|
|
do {
|
|
if (regtry(prog, s))
|
|
return (1);
|
|
} while (*s++ != '\0');
|
|
|
|
/* Failure. */
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
- regtry - try match at specific point
|
|
*/
|
|
static int regtry(regexp *prog, char *string)
|
|
{
|
|
register int i;
|
|
register char **sp;
|
|
register char **ep;
|
|
|
|
reginput = string;
|
|
regstartp = prog->startp;
|
|
regendp = prog->endp;
|
|
|
|
sp = prog->startp;
|
|
ep = prog->endp;
|
|
for (i = NSUBEXP; i > 0; i--) {
|
|
*sp++ = (char *)NULL;
|
|
*ep++ = (char *)NULL;
|
|
}
|
|
if (regmatch(prog->program + 1)) {
|
|
prog->startp[0] = string;
|
|
prog->endp[0] = reginput;
|
|
return (1);
|
|
} else
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
- regmatch - 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 we make 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 a loop instead of
|
|
* by recursion.
|
|
*/
|
|
static int regmatch(char *prog)
|
|
{
|
|
register char *scan; /* Current node. */
|
|
char *nxt; /* nxt node. */
|
|
|
|
scan = prog;
|
|
#ifdef DEBUG
|
|
#ifdef DF_TRACE_DEBUG
|
|
printf("DF_TRACE_DEBUG: static int regmatch() in regexp.c\n");
|
|
#endif
|
|
if (scan != (char *)NULL && regnarrate)
|
|
fprintf(stderr, "%s(\n", regprop(scan));
|
|
#endif
|
|
while (scan != (char *)NULL) {
|
|
#ifdef DEBUG
|
|
if (regnarrate)
|
|
fprintf(stderr, "%s...\n", regprop(scan));
|
|
#endif
|
|
nxt = regnext(scan);
|
|
|
|
switch (OP(scan)) {
|
|
case BOL:
|
|
if (reginput != regbol)
|
|
return (0);
|
|
break;
|
|
case EOL:
|
|
if (*reginput != '\0')
|
|
return (0);
|
|
break;
|
|
case ANY:
|
|
if (*reginput == '\0')
|
|
return (0);
|
|
reginput++;
|
|
break;
|
|
case EXACTLY:{
|
|
register int len;
|
|
register char *opnd;
|
|
|
|
opnd = OPERAND(scan);
|
|
/* Inline the first character, for speed. */
|
|
if (*opnd != *reginput)
|
|
return (0);
|
|
len = strlen(opnd);
|
|
if (len > 1 && strncmp(opnd, reginput, len) != 0)
|
|
return (0);
|
|
reginput += len;
|
|
}
|
|
break;
|
|
case ANYOF:
|
|
if (*reginput == '\0' ||
|
|
strchr(OPERAND(scan), *reginput) == (char *)NULL)
|
|
return (0);
|
|
reginput++;
|
|
break;
|
|
case ANYBUT:
|
|
if (*reginput == '\0' ||
|
|
strchr(OPERAND(scan), *reginput) != (char *)NULL)
|
|
return (0);
|
|
reginput++;
|
|
break;
|
|
case NOTHING:
|
|
break;
|
|
case BACK:
|
|
break;
|
|
case OPEN + 1:
|
|
case OPEN + 2:
|
|
case OPEN + 3:
|
|
case OPEN + 4:
|
|
case OPEN + 5:
|
|
case OPEN + 6:
|
|
case OPEN + 7:
|
|
case OPEN + 8:
|
|
case OPEN + 9:{
|
|
register int no;
|
|
register char *save;
|
|
|
|
no = OP(scan) - OPEN;
|
|
save = reginput;
|
|
|
|
if (regmatch(nxt)) {
|
|
/*
|
|
* Don't set startp if some later invocation of the same
|
|
* parentheses already has.
|
|
*/
|
|
if (regstartp[no] == (char *)NULL)
|
|
regstartp[no] = save;
|
|
return (1);
|
|
} else
|
|
return (0);
|
|
}
|
|
case CLOSE + 1:
|
|
case CLOSE + 2:
|
|
case CLOSE + 3:
|
|
case CLOSE + 4:
|
|
case CLOSE + 5:
|
|
case CLOSE + 6:
|
|
case CLOSE + 7:
|
|
case CLOSE + 8:
|
|
case CLOSE + 9:{
|
|
register int no;
|
|
register char *save;
|
|
|
|
no = OP(scan) - CLOSE;
|
|
save = reginput;
|
|
|
|
if (regmatch(nxt)) {
|
|
/*
|
|
* Don't set endp if some later invocation of the same
|
|
* parentheses already has.
|
|
*/
|
|
if (regendp[no] == (char *)NULL)
|
|
regendp[no] = save;
|
|
return (1);
|
|
} else
|
|
return (0);
|
|
}
|
|
case BRANCH:{
|
|
register char *save;
|
|
|
|
if (OP(nxt) != BRANCH) /* No choice. */
|
|
nxt = OPERAND(scan); /* Avoid recursion. */
|
|
else {
|
|
do {
|
|
save = reginput;
|
|
if (regmatch(OPERAND(scan)))
|
|
return (1);
|
|
reginput = save;
|
|
scan = regnext(scan);
|
|
} while (scan != (char *)NULL && OP(scan) == BRANCH);
|
|
return (0);
|
|
/* NOTREACHED */
|
|
}
|
|
break; /* Xn */
|
|
} /* Xn */
|
|
case STAR:{
|
|
register char nextch;
|
|
register int no;
|
|
register char *save;
|
|
register int minimum;
|
|
|
|
/*
|
|
* Lookahead to avoid useless match attempts when we know
|
|
* what character comes next.
|
|
*/
|
|
nextch = '\0';
|
|
if (OP(nxt) == EXACTLY)
|
|
nextch = *OPERAND(nxt);
|
|
minimum = (OP(scan) == STAR) ? 0 : 1;
|
|
save = reginput;
|
|
no = regrepeat(OPERAND(scan));
|
|
while (no >= minimum) {
|
|
/* If it could work, try it. */
|
|
if (nextch == '\0' || *reginput == nextch)
|
|
if (regmatch(nxt))
|
|
return (1);
|
|
/* Couldn't or didn't -- back up. */
|
|
no--;
|
|
reginput = save + no;
|
|
}
|
|
return (0);
|
|
}
|
|
case END:
|
|
return (1); /* Success! */
|
|
default:
|
|
regerror("memory corruption");
|
|
return (0);
|
|
}
|
|
|
|
scan = nxt;
|
|
}
|
|
|
|
/*
|
|
* We get here only if there's trouble -- normally "case END" is the
|
|
* terminating point.
|
|
*/
|
|
regerror("corrupted pointers");
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
- regrepeat - repeatedly match something simple, report how many
|
|
*/
|
|
static int regrepeat(char *p)
|
|
{
|
|
register int count = 0;
|
|
register char *scan;
|
|
register char *opnd;
|
|
|
|
scan = reginput;
|
|
opnd = OPERAND(p);
|
|
switch (OP(p)) {
|
|
case ANY:
|
|
count = strlen(scan);
|
|
scan += count;
|
|
break;
|
|
case EXACTLY:
|
|
while (*opnd == *scan) {
|
|
count++;
|
|
scan++;
|
|
}
|
|
break;
|
|
case ANYOF:
|
|
while (*scan != '\0' && strchr(opnd, *scan) != (char *)NULL) {
|
|
count++;
|
|
scan++;
|
|
}
|
|
break;
|
|
case ANYBUT:
|
|
while (*scan != '\0' && strchr(opnd, *scan) == (char *)NULL) {
|
|
count++;
|
|
scan++;
|
|
}
|
|
break;
|
|
default: /* Oh dear. Called inappropriately. */
|
|
regerror("internal foulup");
|
|
count = 0; /* Best compromise. */
|
|
break;
|
|
}
|
|
reginput = scan;
|
|
|
|
return (count);
|
|
}
|
|
|
|
|
|
/*
|
|
- regnext - dig the "nxt" pointer out of a node
|
|
*/
|
|
static char *regnext(register char *p)
|
|
{
|
|
register int offset;
|
|
|
|
if (p == ®dummy)
|
|
return ((char *)NULL);
|
|
|
|
offset = NEXT(p);
|
|
if (offset == 0)
|
|
return ((char *)NULL);
|
|
|
|
if (OP(p) == BACK)
|
|
return (p - offset);
|
|
else
|
|
return (p + offset);
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
|
|
#if 0 /* Xn */
|
|
STATIC char *regprop();
|
|
#endif /* Xn */
|
|
|
|
/*
|
|
- regdump - dump a regexp onto stdout in vaguely comprehensible form
|
|
*/
|
|
void regdump(regexp *r)
|
|
{
|
|
register char *s;
|
|
register char op = EXACTLY; /* Arbitrary non-END op. */
|
|
register char *nxt;
|
|
#if 0 /* Xn */
|
|
extern char *strchr();
|
|
#endif /* Xn */
|
|
|
|
|
|
s = r->program + 1;
|
|
while (op != END) { /* While that wasn't END last time... */
|
|
op = OP(s);
|
|
printf("%2d%s", s - r->program, regprop(s)); /* Where, what. */
|
|
nxt = regnext(s);
|
|
if (nxt == (char *)NULL) /* nxt ptr. */
|
|
printf("(0)");
|
|
else
|
|
printf("(%d)", (s - r->program) + (nxt - s));
|
|
s += 3;
|
|
if (op == ANYOF || op == ANYBUT || op == EXACTLY) {
|
|
/* Literal string, where present. */
|
|
while (*s != '\0') {
|
|
putchar(*s);
|
|
s++;
|
|
}
|
|
s++;
|
|
}
|
|
putchar('\n');
|
|
}
|
|
|
|
/* Header fields of interest. */
|
|
if (r->regstart != '\0')
|
|
printf("start `%c' ", r->regstart);
|
|
if (r->reganch)
|
|
printf("anchored ");
|
|
if (r->regmust != (char *)NULL)
|
|
printf("must have \"%s\"", r->regmust);
|
|
printf("\n");
|
|
}
|
|
|
|
/*
|
|
- regprop - printable representation of opcode
|
|
*/
|
|
static char *regprop(char *op)
|
|
{
|
|
register char *p;
|
|
static char buf[50];
|
|
|
|
strcpy(buf, ":");
|
|
|
|
switch (OP(op)) {
|
|
case BOL:
|
|
p = "BOL";
|
|
break;
|
|
case EOL:
|
|
p = "EOL";
|
|
break;
|
|
case ANY:
|
|
p = "ANY";
|
|
break;
|
|
case ANYOF:
|
|
p = "ANYOF";
|
|
break;
|
|
case ANYBUT:
|
|
p = "ANYBUT";
|
|
break;
|
|
case BRANCH:
|
|
p = "BRANCH";
|
|
break;
|
|
case EXACTLY:
|
|
p = "EXACTLY";
|
|
break;
|
|
case NOTHING:
|
|
p = "NOTHING";
|
|
break;
|
|
case BACK:
|
|
p = "BACK";
|
|
break;
|
|
case END:
|
|
p = "END";
|
|
break;
|
|
case OPEN + 1:
|
|
case OPEN + 2:
|
|
case OPEN + 3:
|
|
case OPEN + 4:
|
|
case OPEN + 5:
|
|
case OPEN + 6:
|
|
case OPEN + 7:
|
|
case OPEN + 8:
|
|
case OPEN + 9:
|
|
sprintf(buf + strlen(buf), "OPEN%d", OP(op) - OPEN);
|
|
p = (char *)NULL;
|
|
break;
|
|
case CLOSE + 1:
|
|
case CLOSE + 2:
|
|
case CLOSE + 3:
|
|
case CLOSE + 4:
|
|
case CLOSE + 5:
|
|
case CLOSE + 6:
|
|
case CLOSE + 7:
|
|
case CLOSE + 8:
|
|
case CLOSE + 9:
|
|
sprintf(buf + strlen(buf), "CLOSE%d", OP(op) - CLOSE);
|
|
p = (char *)NULL;
|
|
break;
|
|
case STAR:
|
|
p = "STAR";
|
|
break;
|
|
default:
|
|
regerror("corrupted opcode");
|
|
break;
|
|
}
|
|
if (p != (char *)NULL)
|
|
strcat(buf, p);
|
|
return (buf);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* The following is provided for those people who do not have strcspn() in
|
|
* their C libraries. They should get off their butts and do something
|
|
* about it; at least one public-domain implementation of those (highly
|
|
* useful) string routines has been published on Usenet.
|
|
*/
|
|
#ifdef STRCSPN
|
|
/*
|
|
* strcspn - find length of initial segment of s1 consisting entirely
|
|
* of characters not from s2
|
|
*/
|
|
|
|
static size_t strcspn(const char *s1, const char *s2) /* Xn */
|
|
{
|
|
#ifdef __STDC__ /* Xn */
|
|
register const char *scan1; /* Xn */
|
|
register const char *scan2; /* Xn */
|
|
register size_t count; /* Xn */
|
|
#else /* Xn */
|
|
register char *scan1;
|
|
register char *scan2;
|
|
register uint count; /* Xn */
|
|
#endif /* Xn */
|
|
|
|
count = 0;
|
|
for (scan1 = s1; *scan1 != '\0'; scan1++) {
|
|
for (scan2 = s2; *scan2 != '\0';) /* ++ moved down. */
|
|
if (*scan1 == *scan2++)
|
|
return (count);
|
|
count++;
|
|
}
|
|
return (count);
|
|
}
|
|
#endif
|
|
|
|
|
|
/*
|
|
- regsub - perform substitutions after a regexp match
|
|
*/
|
|
void regsub(regexp *prog, char *source, char *dest)
|
|
{
|
|
register char *src;
|
|
register char *dst;
|
|
register char c;
|
|
register int no;
|
|
register int len;
|
|
extern char *strncpy();
|
|
|
|
if (prog == (regexp *)NULL ||
|
|
source == (char *)NULL || dest == (char *)NULL) {
|
|
regerror("NULL parm to regsub");
|
|
return;
|
|
}
|
|
if (UCHARAT(prog->program) != MAGIC) {
|
|
regerror("damaged regexp fed to regsub");
|
|
return;
|
|
}
|
|
src = source;
|
|
dst = dest;
|
|
while ((c = *src++) != '\0') {
|
|
if (c == '&')
|
|
no = 0;
|
|
else if (c == '\\' && '0' <= *src && *src <= '9')
|
|
no = *src++ - '0';
|
|
else
|
|
no = -1;
|
|
|
|
if (no < 0) { /* Ordinary character. */
|
|
if (c == '\\' && (*src == '\\' || *src == '&'))
|
|
c = *src++;
|
|
*dst++ = c;
|
|
} else if (prog->startp[no] != (char *)NULL &&
|
|
prog->endp[no] != (char *)NULL) {
|
|
len = (int)(prog->endp[no] - prog->startp[no]);
|
|
strncpy(dst, prog->startp[no], len);
|
|
dst += len;
|
|
if (len != 0 && *(dst - 1) == '\0') { /* strncpy hit NUL. */
|
|
regerror("damaged match string");
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
*dst++ = '\0';
|
|
}
|
|
|
|
|
|
void regerror(char *s)
|
|
{
|
|
fprintf(stderr, "regexp(3): %s", s);
|
|
exit(1);
|
|
}
|