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1290 lines
42 KiB
1290 lines
42 KiB
/* $Header: /nw/tony/src/stevie/src/RCS/regexp.c,v 1.5 89/07/07 16:27:11 tony Exp $
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*
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* NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE
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*
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* This is NOT the original regular expression code as written by
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* Henry Spencer. This code has been modified specifically for use
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* with the STEVIE editor, and should not be used apart from compiling
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* STEVIE. If you want a good regular expression library, get the
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* original code. The copyright notice that follows is from the
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* original.
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*
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* NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE
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*
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*
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* regcomp and regexec -- regsub and regerror are elsewhere
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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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*/
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#include "env.h"
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#include <stdio.h>
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#include <string.h>
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#include <malloc.h>
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#include "regexp.h"
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#include "regmagic.h"
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int cstrncmp(char *,char *,int);
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char *cstrchr(char *,char);
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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 "next" pointer, possibly plus an operand. "Next" pointers of
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* all nodes except BRANCH implement concatenation; a "next" 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 string. */
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#define BRANCH 6 /* node Match this alternative, or the next... */
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#define BACK 7 /* no Match "", "next" 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 times. */
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#define PLUS 11 /* node Match this (simple) thing 1 or more times. */
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#define OPEN 20 /* no Mark this point in input as start of #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 "next" pointers, since precedence prevents
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* anything being concatenated to any individual branch. The
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* "next" 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 "next" 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 "next" 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,PLUS '?', and complex '*' and '+', are implemented as circular
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* BRANCH structures using BACK. Simple cases (one character
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* per match) are implemented with STAR and PLUS for speed
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* and to minimize recursive 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 "next" pointer.
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* "Next" 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 "next" 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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* See regmagic.h for one further detail of program structure.
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*/
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/*
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* Utility definitions.
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*/
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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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#define FAIL(m) { regerror(m); return(NULL); }
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#define ISMULT(c) ((c) == '*' || (c) == '+' || (c) == '?')
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#define META "^$.[()|?+*\\"
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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/PLUS operand. */
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#define SPSTART 04 /* Starts with * or +. */
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#define WORST 0 /* Worst case. */
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#ifndef ORIGINAL
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/*
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* The following supports the ability to ignore case in searches.
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*/
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#include <ctype.h>
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int reg_ic = 0; /* set by callers to ignore case */
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/*
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* mkup - convert to upper case IF we're doing caseless compares
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*/
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#define mkup(c) ((reg_ic && islower(c)) ? toupper(c) : (c))
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#endif
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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();
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STATIC char *regbranch();
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STATIC char *regpiece();
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STATIC char *regatom();
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STATIC char *regnode();
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STATIC char *regnext();
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STATIC void regc();
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STATIC void reginsert();
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STATIC void regtail();
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STATIC void regoptail();
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#ifdef STRCSPN
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STATIC int strcspn();
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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 *
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regcomp(exp)
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char *exp;
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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 int len;
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int flags;
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if (exp == 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) == NULL)
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return(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 == 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(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
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* longest literal string that must appear and make it the
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* regmust. Resolve ties in favor of later strings, since
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* the regstart check works with the beginning of the r.e.
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* and avoiding duplication strengthens checking. Not a
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* strong reason, but sufficient in the 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)) >= (size_t)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 *
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reg(paren, flagp)
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int paren; /* Parenthesized? */
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int *flagp;
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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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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(OPEN+parno);
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} else
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ret = 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 == NULL)
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return(NULL);
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if (ret != 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 == NULL)
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return(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((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 != 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 *
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regbranch(flagp)
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int *flagp;
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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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ret = regnode(BRANCH);
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chain = NULL;
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while (*regparse != '\0' && *regparse != '|' && *regparse != ')') {
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latest = regpiece(&flags);
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if (latest == NULL)
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return(NULL);
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*flagp |= flags&HASWIDTH;
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if (chain == 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 == NULL) /* Loop ran zero times. */
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(void) 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 sequences used for ? and the general cases
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* of * and + are somewhat optimized: they use the same NOTHING node as
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* both the endmarker for their branch list and the body of the last branch.
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* It might seem that this node could be dispensed with entirely, but the
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* endmarker role is not redundant.
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*/
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static char *
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regpiece(flagp)
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int *flagp;
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{
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register char *ret;
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register char op;
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register char *next;
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int flags;
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ret = regatom(&flags);
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if (ret == NULL)
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return(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) && op != '?')
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FAIL("*+ operand could be empty");
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*flagp = (op != '+') ? (WORST|SPSTART) : (WORST|HASWIDTH);
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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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} else if (op == '+' && (flags&SIMPLE))
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reginsert(PLUS, ret);
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else if (op == '+') {
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/* Emit x+ as x(&|), where & means "self". */
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next = regnode(BRANCH); /* Either */
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regtail(ret, next);
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regtail(regnode(BACK), ret); /* loop back */
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regtail(next, regnode(BRANCH)); /* or */
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regtail(ret, regnode(NOTHING)); /* null. */
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} else if (op == '?') {
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/* Emit x? as (x|) */
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reginsert(BRANCH, ret); /* Either x */
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regtail(ret, regnode(BRANCH)); /* or */
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next = regnode(NOTHING); /* null. */
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regtail(ret, next);
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regoptail(ret, next);
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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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/*
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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 *
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regatom(flagp)
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int *flagp;
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{
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register char *ret;
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int flags;
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|
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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 != ']') {
|
|
if (*regparse == '-') {
|
|
regparse++;
|
|
if (*regparse == ']' || *regparse == '\0')
|
|
regc('-');
|
|
else {
|
|
class = UCHARAT(regparse-2)+1;
|
|
classend = UCHARAT(regparse);
|
|
if (class > classend+1)
|
|
FAIL("invalid [] range");
|
|
for (; class <= classend; class++)
|
|
regc(class);
|
|
regparse++;
|
|
}
|
|
} else
|
|
regc(*regparse++);
|
|
}
|
|
regc('\0');
|
|
if (*regparse != ']')
|
|
FAIL("unmatched []");
|
|
regparse++;
|
|
*flagp |= HASWIDTH|SIMPLE;
|
|
}
|
|
break;
|
|
case '(':
|
|
ret = reg(1, &flags);
|
|
if (ret == NULL)
|
|
return(NULL);
|
|
*flagp |= flags&(HASWIDTH|SPSTART);
|
|
break;
|
|
case '\0':
|
|
case '|':
|
|
case ')':
|
|
FAIL("internal urp"); /* Supposed to be caught earlier. */
|
|
break;
|
|
case '?':
|
|
case '+':
|
|
case '*':
|
|
FAIL("?+* follows nothing");
|
|
break;
|
|
case '\\':
|
|
if (*regparse == '\0')
|
|
FAIL("trailing \\");
|
|
ret = regnode(EXACTLY);
|
|
regc(*regparse++);
|
|
regc('\0');
|
|
*flagp |= HASWIDTH|SIMPLE;
|
|
break;
|
|
default: {
|
|
register int len;
|
|
register char ender;
|
|
|
|
regparse--;
|
|
len = strcspn(regparse, META);
|
|
if (len <= 0)
|
|
FAIL("internal disaster");
|
|
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 * /* Location. */
|
|
regnode(op)
|
|
char op;
|
|
{
|
|
register char *ret;
|
|
register char *ptr;
|
|
|
|
ret = regcode;
|
|
if (ret == ®dummy) {
|
|
regsize += 3;
|
|
return(ret);
|
|
}
|
|
|
|
ptr = ret;
|
|
*ptr++ = op;
|
|
*ptr++ = '\0'; /* Null "next" pointer. */
|
|
*ptr++ = '\0';
|
|
regcode = ptr;
|
|
|
|
return(ret);
|
|
}
|
|
|
|
/*
|
|
- regc - emit (if appropriate) a byte of code
|
|
*/
|
|
static void
|
|
regc(b)
|
|
char b;
|
|
{
|
|
if (regcode != ®dummy)
|
|
*regcode++ = b;
|
|
else
|
|
regsize++;
|
|
}
|
|
|
|
/*
|
|
- reginsert - insert an operator in front of already-emitted operand
|
|
*
|
|
* Means relocating the operand.
|
|
*/
|
|
static void
|
|
reginsert(op, opnd)
|
|
char op;
|
|
char *opnd;
|
|
{
|
|
register char *src;
|
|
register char *dst;
|
|
register char *place;
|
|
|
|
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(p, val)
|
|
char *p;
|
|
char *val;
|
|
{
|
|
register char *scan;
|
|
register char *temp;
|
|
register int offset;
|
|
|
|
if (p == ®dummy)
|
|
return;
|
|
|
|
/* Find last node. */
|
|
scan = p;
|
|
for (;;) {
|
|
temp = regnext(scan);
|
|
if (temp == NULL)
|
|
break;
|
|
scan = temp;
|
|
}
|
|
|
|
if (OP(scan) == BACK)
|
|
offset = (int)(scan - val);
|
|
else
|
|
offset = (int)(val - scan);
|
|
*(scan+1) = (char)((offset>>8)&0377);
|
|
*(scan+2) = (char)(offset&0377);
|
|
}
|
|
|
|
/*
|
|
- regoptail - regtail on operand of first argument; nop if operandless
|
|
*/
|
|
static void
|
|
regoptail(p, val)
|
|
char *p;
|
|
char *val;
|
|
{
|
|
/* "Operandless" and "op != BRANCH" are synonymous in practice. */
|
|
if (p == 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();
|
|
STATIC int regmatch();
|
|
STATIC int regrepeat();
|
|
|
|
#ifdef DEBUG
|
|
int regnarrate = 0;
|
|
void regdump();
|
|
STATIC char *regprop();
|
|
#endif
|
|
|
|
/*
|
|
- regexec - match a regexp against a string
|
|
*/
|
|
int
|
|
regexec(regexp *prog, char *string, int at_bol)
|
|
{
|
|
register char *s;
|
|
|
|
/* Be paranoid... */
|
|
if (prog == NULL || string == 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 != NULL) {
|
|
s = string;
|
|
while ((s = cstrchr(s, prog->regmust[0])) != NULL) {
|
|
if (cstrncmp(s, prog->regmust, prog->regmlen) == 0)
|
|
break; /* Found it. */
|
|
s++;
|
|
}
|
|
if (s == NULL) /* Not present. */
|
|
return(0);
|
|
}
|
|
|
|
/* Mark beginning of line for ^ . */
|
|
if (at_bol)
|
|
regbol = string; /* is possible to match bol */
|
|
else
|
|
regbol = NULL; /* we aren't there, so don't match it */
|
|
|
|
/* 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 = cstrchr(s, prog->regstart)) != 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 /* 0 failure, 1 success */
|
|
regtry(prog, string)
|
|
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++ = NULL;
|
|
*ep++ = 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 /* 0 failure, 1 success */
|
|
regmatch(prog)
|
|
char *prog;
|
|
{
|
|
register char *scan; /* Current node. */
|
|
char *next; /* Next node. */
|
|
|
|
scan = prog;
|
|
#ifdef DEBUG
|
|
if (scan != NULL && regnarrate)
|
|
fprintf(stderr, "%s(\n", regprop(scan));
|
|
#endif
|
|
while (scan != NULL) {
|
|
#ifdef DEBUG
|
|
if (regnarrate)
|
|
fprintf(stderr, "%s...\n", regprop(scan));
|
|
#endif
|
|
next = 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 (mkup(*opnd) != mkup(*reginput))
|
|
return(0);
|
|
len = strlen(opnd);
|
|
if (len > 1 && cstrncmp(opnd,reginput,len) != 0)
|
|
return(0);
|
|
reginput += len;
|
|
}
|
|
break;
|
|
case ANYOF:
|
|
if (*reginput == '\0' || strchr(OPERAND(scan), *reginput) == NULL)
|
|
return(0);
|
|
reginput++;
|
|
break;
|
|
case ANYBUT:
|
|
if (*reginput == '\0' || strchr(OPERAND(scan), *reginput) != 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(next)) {
|
|
/*
|
|
* Don't set startp if some later
|
|
* invocation of the same parentheses
|
|
* already has.
|
|
*/
|
|
if (regstartp[no] == NULL)
|
|
regstartp[no] = save;
|
|
return(1);
|
|
} else
|
|
return(0);
|
|
}
|
|
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: {
|
|
register int no;
|
|
register char *save;
|
|
|
|
no = OP(scan) - CLOSE;
|
|
save = reginput;
|
|
|
|
if (regmatch(next)) {
|
|
/*
|
|
* Don't set endp if some later
|
|
* invocation of the same parentheses
|
|
* already has.
|
|
*/
|
|
if (regendp[no] == NULL)
|
|
regendp[no] = save;
|
|
return(1);
|
|
} else
|
|
return(0);
|
|
}
|
|
break;
|
|
case BRANCH: {
|
|
register char *save;
|
|
|
|
if (OP(next) != BRANCH) /* No choice. */
|
|
next = OPERAND(scan); /* Avoid recursion. */
|
|
else {
|
|
do {
|
|
save = reginput;
|
|
if (regmatch(OPERAND(scan)))
|
|
return(1);
|
|
reginput = save;
|
|
scan = regnext(scan);
|
|
} while (scan != NULL && OP(scan) == BRANCH);
|
|
return(0);
|
|
/* NOTREACHED */
|
|
}
|
|
}
|
|
break;
|
|
case STAR:
|
|
case PLUS: {
|
|
register char nextch;
|
|
register int no;
|
|
register char *save;
|
|
register int min;
|
|
|
|
/*
|
|
* Lookahead to avoid useless match attempts
|
|
* when we know what character comes next.
|
|
*/
|
|
nextch = '\0';
|
|
if (OP(next) == EXACTLY)
|
|
nextch = *OPERAND(next);
|
|
min = (OP(scan) == STAR) ? 0 : 1;
|
|
save = reginput;
|
|
no = regrepeat(OPERAND(scan));
|
|
while (no >= min) {
|
|
/* If it could work, try it. */
|
|
if (nextch == '\0' || *reginput == nextch)
|
|
if (regmatch(next))
|
|
return(1);
|
|
/* Couldn't or didn't -- back up. */
|
|
no--;
|
|
reginput = save + no;
|
|
}
|
|
return(0);
|
|
}
|
|
break;
|
|
case END:
|
|
return(1); /* Success! */
|
|
break;
|
|
default:
|
|
regerror("memory corruption");
|
|
return(0);
|
|
break;
|
|
}
|
|
|
|
scan = next;
|
|
}
|
|
|
|
/*
|
|
* 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(p)
|
|
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 (mkup(*opnd) == mkup(*scan)) {
|
|
count++;
|
|
scan++;
|
|
}
|
|
break;
|
|
case ANYOF:
|
|
while (*scan != '\0' && strchr(opnd, *scan) != NULL) {
|
|
count++;
|
|
scan++;
|
|
}
|
|
break;
|
|
case ANYBUT:
|
|
while (*scan != '\0' && strchr(opnd, *scan) == NULL) {
|
|
count++;
|
|
scan++;
|
|
}
|
|
break;
|
|
default: /* Oh dear. Called inappropriately. */
|
|
regerror("internal foulup");
|
|
count = 0; /* Best compromise. */
|
|
break;
|
|
}
|
|
reginput = scan;
|
|
|
|
return(count);
|
|
}
|
|
|
|
/*
|
|
- regnext - dig the "next" pointer out of a node
|
|
*/
|
|
static char *
|
|
regnext(p)
|
|
register char *p;
|
|
{
|
|
register int offset;
|
|
|
|
if (p == ®dummy)
|
|
return(NULL);
|
|
|
|
offset = NEXT(p);
|
|
if (offset == 0)
|
|
return(NULL);
|
|
|
|
if (OP(p) == BACK)
|
|
return(p-offset);
|
|
else
|
|
return(p+offset);
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
|
|
STATIC char *regprop();
|
|
|
|
/*
|
|
- regdump - dump a regexp onto stdout in vaguely comprehensible form
|
|
*/
|
|
void
|
|
regdump(r)
|
|
regexp *r;
|
|
{
|
|
register char *s;
|
|
register char op = EXACTLY; /* Arbitrary non-END op. */
|
|
register char *next;
|
|
|
|
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. */
|
|
next = regnext(s);
|
|
if (next == NULL) /* Next ptr. */
|
|
printf("(0)");
|
|
else
|
|
printf("(%d)", (s-r->program)+(next-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 != NULL)
|
|
printf("must have \"%s\"", r->regmust);
|
|
printf("\n");
|
|
}
|
|
|
|
/*
|
|
- regprop - printable representation of opcode
|
|
*/
|
|
static char *
|
|
regprop(op)
|
|
char *op;
|
|
{
|
|
register char *p;
|
|
static char buf[50];
|
|
|
|
(void) 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 = 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 = NULL;
|
|
break;
|
|
case STAR:
|
|
p = "STAR";
|
|
break;
|
|
case PLUS:
|
|
p = "PLUS";
|
|
break;
|
|
default:
|
|
regerror("corrupted opcode");
|
|
break;
|
|
}
|
|
if (p != NULL)
|
|
(void) 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 int
|
|
strcspn(s1, s2)
|
|
char *s1;
|
|
char *s2;
|
|
{
|
|
register char *scan1;
|
|
register char *scan2;
|
|
register int count;
|
|
|
|
count = 0;
|
|
for (scan1 = s1; *scan1 != '\0'; scan1++) {
|
|
for (scan2 = s2; *scan2 != '\0';) /* ++ moved down. */
|
|
if (*scan1 == *scan2++)
|
|
return(count);
|
|
count++;
|
|
}
|
|
return(count);
|
|
}
|
|
#endif
|
|
|
|
int
|
|
cstrncmp(s1, s2, n)
|
|
char *s1, *s2;
|
|
int n;
|
|
{
|
|
char *p, *S1, *S2, *strsave();
|
|
int rval;
|
|
|
|
if (!reg_ic)
|
|
return (strncmp(s1, s2, n));
|
|
|
|
S1 = strsave(s1);
|
|
S2 = strsave(s2);
|
|
|
|
for (p = S1; *p ;p++)
|
|
if (islower(*p))
|
|
*p = (char)toupper(*p);
|
|
|
|
for (p = S2; *p ;p++)
|
|
if (islower(*p))
|
|
*p = (char)toupper(*p);
|
|
|
|
rval = strncmp(S1, S2, n);
|
|
|
|
free(S1);
|
|
free(S2);
|
|
|
|
return rval;
|
|
}
|
|
|
|
char *
|
|
cstrchr(
|
|
char *s,
|
|
char c)
|
|
{
|
|
char *p;
|
|
|
|
for (p = s; *p ;p++) {
|
|
if (mkup(*p) == mkup(c))
|
|
return p;
|
|
}
|
|
return NULL;
|
|
}
|