+++ /dev/null
-/*
- * regcomp and regexec -- regsub and regerror are elsewhere
- *
- * Copyright (c) 1986 by University of Toronto.
- * Written by Henry Spencer. Not derived from licensed software.
- *
- * Permission is granted to anyone to use this software for any
- * purpose on any computer system, and to redistribute it freely,
- * subject to the following restrictions:
- *
- * 1. The author is not responsible for the consequences of use of
- * this software, no matter how awful, even if they arise
- * from defects in it.
- *
- * 2. The origin of this software must not be misrepresented, either
- * by explicit claim or by omission.
- *
- * 3. Altered versions must be plainly marked as such, and must not
- * be misrepresented as being the original software.
- *** THIS IS AN ALTERED VERSION. It was altered by John Gilmore,
- *** hoptoad!gnu, on 27 Dec 1986, to add \n as an alternative to |
- *** to assist in implementing egrep.
- *** THIS IS AN ALTERED VERSION. It was altered by John Gilmore,
- *** hoptoad!gnu, on 27 Dec 1986, to add \< and \> for word-matching
- *** as in BSD grep and ex.
- *** THIS IS AN ALTERED VERSION. It was altered by John Gilmore,
- *** hoptoad!gnu, on 28 Dec 1986, to optimize characters quoted with \.
- *** THIS IS AN ALTERED VERSION. It was altered by James A. Woods,
- *** ames!jaw, on 19 June 1987, to quash a regcomp() redundancy.
- *** THIS IS AN ALTERED VERSION. It was altered by Geoffrey Noer,
- *** noer@cygnus.com, on 6 Oct 1997, to change the prototype format
- *** for inclusion in the Cygwin32 library.
- *
- * Beware that some of this code is subtly aware of the way operator
- * precedence is structured in regular expressions. Serious changes in
- * regular-expression syntax might require a total rethink.
- */
-
-#include "winsup.h"
-#include "regexp.h"
-#include <stdio.h>
-#include <string.h>
-#include <ctype.h>
-#include <stdlib.h>
-#include "regmagic.h"
-
-/*
- * The "internal use only" fields in regexp.h are present to pass info from
- * compile to execute that permits the execute phase to run lots faster on
- * simple cases. They are:
- *
- * regstart char that must begin a match; '\0' if none obvious
- * reganch is the match anchored (at beginning-of-line only)?
- * regmust string (pointer into program) that match must include, or NULL
- * regmlen length of regmust string
- *
- * Regstart and reganch permit very fast decisions on suitable starting points
- * for a match, cutting down the work a lot. Regmust permits fast rejection
- * of lines that cannot possibly match. The regmust tests are costly enough
- * that regcomp() supplies a regmust only if the r.e. contains something
- * potentially expensive (at present, the only such thing detected is * or +
- * at the start of the r.e., which can involve a lot of backup). Regmlen is
- * supplied because the test in regexec() needs it and regcomp() is computing
- * it anyway.
- */
-
-/*
- * Structure for regexp "program". This is essentially a linear encoding
- * of a nondeterministic finite-state machine (aka syntax charts or
- * "railroad normal form" in parsing technology). Each node is an opcode
- * plus a "next" pointer, possibly plus an operand. "Next" pointers of
- * all nodes except BRANCH implement concatenation; a "next" pointer with
- * a BRANCH on both ends of it is connecting two alternatives. (Here we
- * have one of the subtle syntax dependencies: an individual BRANCH (as
- * opposed to a collection of them) is never concatenated with anything
- * because of operator precedence.) The operand of some types of node is
- * a literal string; for others, it is a node leading into a sub-FSM. In
- * particular, the operand of a BRANCH node is the first node of the branch.
- * (NB this is *not* a tree structure: the tail of the branch connects
- * to the thing following the set of BRANCHes.) The opcodes are:
- */
-
-/* definition number opnd? meaning */
-#define END 0 /* no End of program. */
-#define BOL 1 /* no Match "" at beginning of line. */
-#define EOL 2 /* no Match "" at end of line. */
-#define ANY 3 /* no Match any one character. */
-#define ANYOF 4 /* str Match any character in this string. */
-#define ANYBUT 5 /* str Match any character not in this string. */
-#define BRANCH 6 /* node Match this alternative, or the next... */
-#define BACK 7 /* no Match "", "next" ptr points backward. */
-#define EXACTLY 8 /* str Match this string. */
-#define NOTHING 9 /* no Match empty string. */
-#define STAR 10 /* node Match this (simple) thing 0 or more times. */
-#define PLUS 11 /* node Match this (simple) thing 1 or more times. */
-#define WORDA 12 /* no Match "" at wordchar, where prev is nonword */
-#define WORDZ 13 /* no Match "" at nonwordchar, where prev is word */
-#define OPEN 20 /* no Mark this point in input as start of #n. */
- /* OPEN+1 is number 1, etc. */
-#define CLOSE 30 /* no Analogous to OPEN. */
-
-/*
- * Opcode notes:
- *
- * BRANCH The set of branches constituting a single choice are hooked
- * together with their "next" pointers, since precedence prevents
- * anything being concatenated to any individual branch. The
- * "next" pointer of the last BRANCH in a choice points to the
- * thing following the whole choice. This is also where the
- * final "next" pointer of each individual branch points; each
- * branch starts with the operand node of a BRANCH node.
- *
- * BACK Normal "next" pointers all implicitly point forward; BACK
- * exists to make loop structures possible.
- *
- * STAR,PLUS '?', and complex '*' and '+', are implemented as circular
- * BRANCH structures using BACK. Simple cases (one character
- * per match) are implemented with STAR and PLUS for speed
- * and to minimize recursive plunges.
- *
- * OPEN,CLOSE ...are numbered at compile time.
- */
-
-/*
- * A node is one char of opcode followed by two chars of "next" pointer.
- * "Next" pointers are stored as two 8-bit pieces, high order first. The
- * value is a positive offset from the opcode of the node containing it.
- * An operand, if any, simply follows the node. (Note that much of the
- * code generation knows about this implicit relationship.)
- *
- * Using two bytes for the "next" pointer is vast overkill for most things,
- * but allows patterns to get big without disasters.
- */
-#define OP(p) (*(p))
-#define NEXT(p) (((*((p)+1)&0377)<<8) + (*((p)+2)&0377))
-#define OPERAND(p) ((p) + 3)
-
-/*
- * See regmagic.h for one further detail of program structure.
- */
-
-
-/*
- * Utility definitions.
- */
-#ifndef CHARBITS
-#define UCHARAT(p) ((int)*(unsigned char *)(p))
-#else
-#define UCHARAT(p) ((int)*(p)&CHARBITS)
-#endif
-
-#define FAIL(m) { regerror(m); return(NULL); }
-#define ISMULT(c) ((c) == '*' || (c) == '+' || (c) == '?')
-
-/*
- * Flags to be passed up and down.
- */
-#define HASWIDTH 01 /* Known never to match null string. */
-#define SIMPLE 02 /* Simple enough to be STAR/PLUS operand. */
-#define SPSTART 04 /* Starts with * or +. */
-#define WORST 0 /* Worst case. */
-
-/*
- * Global work variables for regcomp().
- */
-static char *regparse; /* Input-scan pointer. */
-static int regnpar; /* () count. */
-static char regdummy;
-static char *regcode; /* Code-emit pointer; ®dummy = don't. */
-static long regsize; /* Code size. */
-
-/*
- * Forward declarations for regcomp()'s friends.
- */
-#ifndef STATIC
-#define STATIC static
-#endif
-STATIC char *reg (int, int *);
-STATIC char *regbranch (int *);
-STATIC char *regpiece (int *);
-STATIC char *regatom (int *);
-STATIC char *regnode (char);
-STATIC char *regnext (char *);
-STATIC void regc (char);
-STATIC void reginsert (char, char *);
-STATIC void regtail (char *, char *);
-STATIC void regoptail (char *, char *);
-#ifdef STRCSPN
-STATIC int strcspn (char *, char *);
-#endif
-
-/*
- - regcomp - compile a regular expression into internal code
- *
- * We can't allocate space until we know how big the compiled form will be,
- * but we can't compile it (and thus know how big it is) until we've got a
- * place to put the code. So we cheat: we compile it twice, once with code
- * generation turned off and size counting turned on, and once "for real".
- * This also means that we don't allocate space until we are sure that the
- * thing really will compile successfully, and we never have to move the
- * code and thus invalidate pointers into it. (Note that it has to be in
- * one piece because free() must be able to free it all.)
- *
- * Beware that the optimization-preparation code in here knows about some
- * of the structure of the compiled regexp.
- */
-regexp * __declspec(dllexport)
-regcomp(exp)
-const char *exp;
-{
- register regexp *r;
- register char *scan;
- register char *longest;
- register int len;
- int flags;
-
- if (exp == NULL)
- FAIL("NULL argument");
-
- /* First pass: determine size, legality. */
-#ifdef notdef
- if (exp[0] == '.' && exp[1] == '*') exp += 2; /* aid grep */
-#endif
- regparse = (char *)exp;
- regnpar = 1;
- regsize = 0L;
- regcode = ®dummy;
- regc(MAGIC);
- if (reg(0, &flags) == NULL)
- return(NULL);
-
- /* Small enough for pointer-storage convention? */
- if (regsize >= 32767L) /* Probably could be 65535L. */
- FAIL("regexp too big");
-
- /* Allocate space. */
- r = (regexp *)malloc(sizeof(regexp) + (unsigned)regsize);
- if (r == NULL)
- FAIL("out of space");
-
- /* Second pass: emit code. */
- regparse = (char *)exp;
- regnpar = 1;
- regcode = r->program;
- regc(MAGIC);
- if (reg(0, &flags) == NULL)
- return(NULL);
-
- /* Dig out information for optimizations. */
- r->regstart = '\0'; /* Worst-case defaults. */
- r->reganch = 0;
- r->regmust = NULL;
- r->regmlen = 0;
- scan = r->program+1; /* First BRANCH. */
- if (OP(regnext(scan)) == END) { /* Only one top-level choice. */
- scan = OPERAND(scan);
-
- /* Starting-point info. */
- if (OP(scan) == EXACTLY)
- r->regstart = *OPERAND(scan);
- else if (OP(scan) == BOL)
- r->reganch++;
-
- /*
- * If there's something expensive in the r.e., find the
- * longest literal string that must appear and make it the
- * regmust. Resolve ties in favor of later strings, since
- * the regstart check works with the beginning of the r.e.
- * and avoiding duplication strengthens checking. Not a
- * strong reason, but sufficient in the absence of others.
- */
- if (flags&SPSTART) {
- longest = NULL;
- len = 0;
- for (; scan != NULL; scan = regnext(scan))
- if (OP(scan) == EXACTLY && (int) strlen(OPERAND(scan)) >= len) {
- longest = OPERAND(scan);
- len = strlen(OPERAND(scan));
- }
- r->regmust = longest;
- r->regmlen = len;
- }
- }
-
- return(r);
-}
-
-/*
- - reg - regular expression, i.e. main body or parenthesized thing
- *
- * Caller must absorb opening parenthesis.
- *
- * Combining parenthesis handling with the base level of regular expression
- * is a trifle forced, but the need to tie the tails of the branches to what
- * follows makes it hard to avoid.
- */
-static char *
-reg(paren, flagp)
-int paren; /* Parenthesized? */
-int *flagp;
-{
- register char *ret;
- register char *br;
- register char *ender;
- register int parno = 0;
- int flags;
-
- *flagp = HASWIDTH; /* Tentatively. */
-
- /* Make an OPEN node, if parenthesized. */
- if (paren) {
- if (regnpar >= NSUBEXP)
- FAIL("too many ()");
- parno = regnpar;
- regnpar++;
- ret = regnode(OPEN+parno);
- } else
- ret = NULL;
-
- /* Pick up the branches, linking them together. */
- br = regbranch(&flags);
- if (br == NULL)
- return(NULL);
- if (ret != NULL)
- regtail(ret, br); /* OPEN -> first. */
- else
- ret = br;
- if (!(flags&HASWIDTH))
- *flagp &= ~HASWIDTH;
- *flagp |= flags&SPSTART;
- while (*regparse == '|' || *regparse == '\n') {
- regparse++;
- br = regbranch(&flags);
- if (br == NULL)
- return(NULL);
- regtail(ret, br); /* BRANCH -> BRANCH. */
- if (!(flags&HASWIDTH))
- *flagp &= ~HASWIDTH;
- *flagp |= flags&SPSTART;
- }
-
- /* Make a closing node, and hook it on the end. */
- ender = regnode((paren) ? CLOSE+parno : END);
- regtail(ret, ender);
-
- /* Hook the tails of the branches to the closing node. */
- for (br = ret; br != NULL; br = regnext(br))
- regoptail(br, ender);
-
- /* Check for proper termination. */
- if (paren && *regparse++ != ')') {
- FAIL("unmatched ()");
- } else if (!paren && *regparse != '\0') {
- if (*regparse == ')') {
- FAIL("unmatched ()");
- } else
- FAIL("junk on end"); /* "Can't happen". */
- /* NOTREACHED */
- }
-
- return(ret);
-}
-
-/*
- - regbranch - one alternative of an | operator
- *
- * Implements the concatenation operator.
- */
-static char *
-regbranch(flagp)
-int *flagp;
-{
- register char *ret;
- register char *chain;
- register char *latest;
- int flags;
-
- *flagp = WORST; /* Tentatively. */
-
- ret = regnode(BRANCH);
- chain = NULL;
- while (*regparse != '\0' && *regparse != ')' &&
- *regparse != '\n' && *regparse != '|') {
- latest = regpiece(&flags);
- if (latest == NULL)
- return(NULL);
- *flagp |= flags&HASWIDTH;
- if (chain == NULL) /* First piece. */
- *flagp |= flags&SPSTART;
- else
- regtail(chain, latest);
- chain = latest;
- }
- if (chain == NULL) /* Loop ran zero times. */
- (void) regnode(NOTHING);
-
- return(ret);
-}
-
-/*
- - regpiece - something followed by possible [*+?]
- *
- * Note that the branching code sequences used for ? and the general cases
- * of * and + are somewhat optimized: they use the same NOTHING node as
- * both the endmarker for their branch list and the body of the last branch.
- * It might seem that this node could be dispensed with entirely, but the
- * endmarker role is not redundant.
- */
-static char *
-regpiece(flagp)
-int *flagp;
-{
- register char *ret;
- register char op;
- register char *next;
- int flags;
-
- ret = regatom(&flags);
- if (ret == NULL)
- return(NULL);
-
- op = *regparse;
- if (!ISMULT(op)) {
- *flagp = flags;
- return(ret);
- }
-
- if (!(flags&HASWIDTH) && op != '?')
- FAIL("*+ operand could be empty");
- *flagp = (op != '+') ? (WORST|SPSTART) : (WORST|HASWIDTH);
-
- if (op == '*' && (flags&SIMPLE))
- reginsert(STAR, ret);
- else if (op == '*') {
- /* Emit x* as (x&|), where & means "self". */
- reginsert(BRANCH, ret); /* Either x */
- regoptail(ret, regnode(BACK)); /* and loop */
- regoptail(ret, ret); /* back */
- regtail(ret, regnode(BRANCH)); /* or */
- regtail(ret, regnode(NOTHING)); /* null. */
- } else if (op == '+' && (flags&SIMPLE))
- reginsert(PLUS, ret);
- else if (op == '+') {
- /* Emit x+ as x(&|), where & means "self". */
- next = regnode(BRANCH); /* Either */
- regtail(ret, next);
- regtail(regnode(BACK), ret); /* loop back */
- regtail(next, regnode(BRANCH)); /* or */
- regtail(ret, regnode(NOTHING)); /* null. */
- } else if (op == '?') {
- /* Emit x? as (x|) */
- reginsert(BRANCH, ret); /* Either x */
- regtail(ret, regnode(BRANCH)); /* or */
- next = regnode(NOTHING); /* null. */
- regtail(ret, next);
- regoptail(ret, next);
- }
- regparse++;
- if (ISMULT(*regparse))
- FAIL("nested *?+");
-
- return(ret);
-}
-
-/*
- - regatom - the lowest level
- *
- * Optimization: gobbles an entire sequence of ordinary characters so that
- * it can turn them into a single node, which is smaller to store and
- * faster to run. Backslashed characters are exceptions, each becoming a
- * separate node; the code is simpler that way and it's not worth fixing.
- */
-static char *
-regatom(flagp)
-int *flagp;
-{
- register char *ret;
- int flags;
-
- *flagp = WORST; /* Tentatively. */
-
- switch (*regparse++) {
- /* FIXME: these chars only have meaning at beg/end of pat? */
- case '^':
- ret = regnode(BOL);
- break;
- case '$':
- ret = regnode(EOL);
- break;
- case '.':
- ret = regnode(ANY);
- *flagp |= HASWIDTH|SIMPLE;
- break;
- case '[': {
- register int class;
- register int classend;
-
- if (*regparse == '^') { /* Complement of range. */
- ret = regnode(ANYBUT);
- regparse++;
- } else
- ret = regnode(ANYOF);
- if (*regparse == ']' || *regparse == '-')
- regc(*regparse++);
- 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 '\n':
- case ')':
- FAIL("internal urp"); /* Supposed to be caught earlier. */
- break;
- case '?':
- case '+':
- case '*':
- FAIL("?+* follows nothing");
- break;
- case '\\':
- switch (*regparse++) {
- case '\0':
- FAIL("trailing \\");
- break;
- case '<':
- ret = regnode(WORDA);
- break;
- case '>':
- ret = regnode(WORDZ);
- break;
- /* FIXME: Someday handle \1, \2, ... */
- default:
- /* Handle general quoted chars in exact-match routine */
- goto de_fault;
- }
- break;
- de_fault:
- default:
- /*
- * Encode a string of characters to be matched exactly.
- *
- * This is a bit tricky due to quoted chars and due to
- * '*', '+', and '?' taking the SINGLE char previous
- * as their operand.
- *
- * On entry, the char at regparse[-1] is going to go
- * into the string, no matter what it is. (It could be
- * following a \ if we are entered from the '\' case.)
- *
- * Basic idea is to pick up a good char in ch and
- * examine the next char. If it's *+? then we twiddle.
- * If it's \ then we frozzle. If it's other magic char
- * we push ch and terminate the string. If none of the
- * above, we push ch on the string and go around again.
- *
- * regprev is used to remember where "the current char"
- * starts in the string, if due to a *+? we need to back
- * up and put the current char in a separate, 1-char, string.
- * When regprev is NULL, ch is the only char in the
- * string; this is used in *+? handling, and in setting
- * flags |= SIMPLE at the end.
- */
- {
- char *regprev;
- register char ch = 0;
-
- regparse--; /* Look at cur char */
- ret = regnode(EXACTLY);
- for ( regprev = 0 ; ; ) {
- ch = *regparse++; /* Get current char */
- switch (*regparse) { /* look at next one */
-
- default:
- regc(ch); /* Add cur to string */
- break;
-
- case '.': case '[': case '(':
- case ')': case '|': case '\n':
- case '$': case '^':
- case '\0':
- /* FIXME, $ and ^ should not always be magic */
- magic:
- regc(ch); /* dump cur char */
- goto done; /* and we are done */
-
- case '?': case '+': case '*':
- if (!regprev) /* If just ch in str, */
- goto magic; /* use it */
- /* End mult-char string one early */
- regparse = regprev; /* Back up parse */
- goto done;
-
- case '\\':
- regc(ch); /* Cur char OK */
- switch (regparse[1]){ /* Look after \ */
- case '\0':
- case '<':
- case '>':
- /* FIXME: Someday handle \1, \2, ... */
- goto done; /* Not quoted */
- default:
- /* Backup point is \, scan * point is after it. */
- regprev = regparse;
- regparse++;
- continue; /* NOT break; */
- }
- }
- regprev = regparse; /* Set backup point */
- }
- done:
- regc('\0');
- *flagp |= HASWIDTH;
- if (!regprev) /* One char? */
- *flagp |= SIMPLE;
- }
- 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 = scan - val;
- else
- offset = val - scan;
- *(scan+1) = (offset>>8)&0377;
- *(scan+2) = 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 (const regexp *, const char *);
-STATIC int regmatch (char *);
-STATIC int regrepeat (char *);
-
-#ifdef DEBUG
-int regnarrate = 0;
-void regdump __P((regexp *));
-STATIC char *regprop __P((char *));
-#endif
-
-/*
- - regexec - match a regexp against a string
- */
-int __declspec(dllexport)
-regexec(prog, string)
-register const regexp *prog;
-register const char *string;
-{
- 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 = (char *)string;
- while ((s = strchr(s, prog->regmust[0])) != NULL) {
- if (strncmp(s, prog->regmust, prog->regmlen) == 0)
- break; /* Found it. */
- s++;
- }
- if (s == NULL) /* Not present. */
- return(0);
- }
-
- /* Mark beginning of line for ^ . */
- regbol = (char *)string;
-
- /* Simplest case: anchored match need be tried only once. */
- if (prog->reganch)
- return(regtry(prog, string));
-
- /* Messy cases: unanchored match. */
- s = (char *)string;
- if (prog->regstart != '\0')
- /* We know what char it must start with. */
- while ((s = strchr(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)
-const regexp *prog;
-const char *string;
-{
- register int i;
- register char **sp;
- register char **ep;
-
- reginput = (char *)string; /* XXX */
- regstartp = (char **)prog->startp; /* XXX */
- regendp = (char **)prog->endp; /* XXX */
-
- sp = (char **)prog->startp; /* XXX */
- ep = (char **)prog->endp; /* XXX */
- for (i = NSUBEXP; i > 0; i--) {
- *sp++ = NULL;
- *ep++ = NULL;
- }
- if (regmatch((char *)prog->program + 1)) { /* XXX */
- ((regexp *)prog)->startp[0] = (char *)string; /* XXX */
- ((regexp *)prog)->endp[0] = reginput; /* XXX */
- 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 WORDA:
- /* Must be looking at a letter, digit, or _ */
- if ((!isalnum(*reginput)) && *reginput != '_')
- return(0);
- /* Prev must be BOL or nonword */
- if (reginput > regbol &&
- (isalnum(reginput[-1]) || reginput[-1] == '_'))
- return(0);
- break;
- case WORDZ:
- /* Must be looking at non letter, digit, or _ */
- if (isalnum(*reginput) || *reginput == '_')
- return(0);
- /* We don't care what the previous char was */
- 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) == 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 (*opnd == *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
-
-/*
- - 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;
- extern char *strchr();
-
-
- 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;
- case WORDA:
- p = "WORDA";
- break;
- case WORDZ:
- p = "WORDZ";
- 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
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