MDEV-4425 REGEXP enhancements

1 files changed, 0 insertions, 1348 deletions

diff --git a/regex/regexp.c b/regex/regexp.c
deleted file mode 100644
index 8ddf90f2943..00000000000
--- a/regex/regexp.c
+++ /dev/null
@@ -1,1348 +0,0 @@
-/*
- *
- * regexp.c - regular expression matching
- *
- * DESCRIPTION
- *
- *	Underneath the reformatting and comment blocks which were added to
- *	make it consistent with the rest of the code, you will find a
- *	modified version of Henry Specer's regular expression library.
- *	Henry's functions were modified to provide the minimal regular
- *	expression matching, as required by P1003.  Henry's code was
- *	copyrighted, and copy of the copyright message and restrictions
- *	are provided, verbatim, below:
- *
- *	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 version modified by Ian Phillipps to return pointer to terminating
- * NUL on substitution string. [ Temp mail address ex-igp@camcon.co.uk ]
- *
- *	Altered by amylaar to support excompatible option and the
- *      operators \< and >\ . ( 7.Sep. 1991 )
- *
- * regsub altered by amylaar to take an additional parameter specifying
- * maximum number of bytes that can be written to the memory region
- * pointed to by dest
- *
- * Also altered by Fredrik Hubinette to handle the + operator and
- * eight-bit chars. Mars 22 1996
- *
- *
- * 	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.
- *
- * AUTHORS
- *
- *     Mark H. Colburn, NAPS International (mark@jhereg.mn.org)
- *     Henry Spencer, University of Torronto (henry@utzoo.edu)
- *
- * Sponsored by The USENIX Association for public distribution.
- *
- */
-
-/* Headers */
-#include "my_global.h"
-#include <ctype.h>
-#include "regexp.h"
-#ifdef	__WIN__
-#include <string.h>
-#else
-#include "memory.h"
-#include "error.h"
-#endif
-
-/*
- * 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 "nxt" pointer, possibly plus an operand.  "Nxt" pointers of
- * all nodes except BRANCH implement concatenation; a "nxt" 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
-				 * nxt... */
-#define	BACK	7		/* no	Match "", "nxt" 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 WORDSTART 11		/* node matching a start of a word          */
-#define WORDEND 12		/* node matching an end of a 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 "nxt" pointers, since precedence prevents
- *		anything being concatenated to any individual branch.  The
- *		"nxt" pointer of the last BRANCH in a choice points to the
- *		thing following the whole choice.  This is also where the
- *		final "nxt" pointer of each individual branch points; each
- *		branch starts with the operand node of a BRANCH node.
- *
- * BACK		Normal "nxt" pointers all implicitly point forward; BACK
- *		exists to make loop structures possible.
- *
- * STAR		complex '*', are implemented as circular BRANCH structures
- *		using BACK.  Simple cases (one character per match) are
- *		implemented with STAR 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 "nxt" pointer.
- * "Nxt" 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 "nxt" 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)
-
-/*
- * The first byte of the regexp internal "program" is actually this magic
- * number; the start node begins in the second byte.
- */
-#define	MAGIC	0234
-
-/*
- * Utility definitions.
- */
-
-#ifdef	__WIN__
-#define error(X,Y) fprintf(stderr, X, Y)
-#endif
-#define regerror(X) error("Regexp: %s\n",X);
-#define SPECIAL 0x100
-#define LBRAC	('('|SPECIAL)
-#define RBRAC	(')'|SPECIAL)
-#define ASTERIX	('*'|SPECIAL)
-#define PLUS	('+'|SPECIAL)
-#define OR_OP	('|'|SPECIAL)
-#define DOLLAR	('$'|SPECIAL)
-#define DOT	('.'|SPECIAL)
-#define CARET	('^'|SPECIAL)
-#define LSQBRAC ('['|SPECIAL)
-#define RSQBRAC (']'|SPECIAL)
-#define LSHBRAC ('<'|SPECIAL)
-#define RSHBRAC ('>'|SPECIAL)
-#define	FAIL(m)	{ regerror(m); return(NULL); }
-#define	ISMULT(c)	((c) == ASTERIX || (c)==PLUS)
-#define	META	"^$.[()|*+\\"
-#ifndef CHARBITS
-#define CHARBITS	0xff
-#define	UCHARAT(p)	((int)*(unsigned char *)(p))
-#else
-#define	UCHARAT(p)	((int)*(p)&CHARBITS)
-#endif
-#define ISWORDPART(c) ( isalnum(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 operand. */
-#define	SPSTART		04	/* Starts with * */
-#define	WORST		0	/* Worst case. */
-#ifdef __WIN__
-#define	STRCHR(A,B)	strchr(A,B)
-#endif
-
-/*
- * Global work variables for regcomp().
- */
-static short   *regparse;	/* Input-scan pointer. */
-static int      regnpar;	/* () count. */
-static char     regdummy;
-static char    *regcode;	/* Code-emit pointer; &regdummy = don't. */
-static long     regsize;	/* Code size. */
-
-/*
- * Forward declarations for regcomp()'s friends.
- */
-#ifndef STATIC
-#define	STATIC	static
-#endif
-STATIC char    *reg();
-STATIC char    *regbranch();
-STATIC char    *regpiece();
-STATIC char    *regatom();
-STATIC char    *regnode();
-STATIC char    *regnext();
-STATIC void     regc();
-STATIC void     reginsert();
-STATIC void     regtail();
-STATIC void     regoptail();
-
-/*
- - 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 *regcomp(exp,excompat)
-char   *exp;
-int		excompat;	/* \( \) operators like in unix ex */
-{
-    register regexp *r;
-    register char  *scan;
-    register char  *longest;
-    register int    len;
-    int             flags;
-    short	   *exp2,*dest,c;
-
-    if (exp == (char *)NULL)
-	FAIL("NULL argument");
-
-    exp2=(short*)malloc( (strlen(exp)+1) * (sizeof(short[8])/sizeof(char[8])) );
-    for ( scan=exp,dest=exp2;( c= UCHARAT(scan++)); ) {
-	switch (c) {
-	    case '(':
-	    case ')':
-		*dest++ = excompat ? c : c | SPECIAL;
-		break;
-	    case '.':
-	    case '*':
-	    case '+':
-	    case '|':
-	    case '$':
-	    case '^':
-	    case '[':
-	    case ']':
-		*dest++ =  c | SPECIAL;
-		break;
-	    case '\\':
-		switch ( c = *scan++ ) {
-		    case '(':
-		    case ')':
-			*dest++ = excompat ? c | SPECIAL : c;
-			break;
-		    case '<':
-		    case '>':
-			*dest++ = c | SPECIAL;
-			break;
-		    case '{':
-		    case '}':
-			FAIL("sorry, unimplemented operator");
-		    case 'b': *dest++ = '\b'; break;
-		    case 't': *dest++ = '\t'; break;
-		    case 'r': *dest++ = '\r'; break;
-		    default:
-			*dest++ = c;
-		}
-		break;
-	    default:
-		*dest++ = c;
-	}
-    }
-    *dest=0;
-    /* First pass: determine size, legality. */
-    regparse = exp2;
-    regnpar = 1;
-    regsize = 0L;
-    regcode = &regdummy;
-    regc(MAGIC);
-    if (reg(0, &flags) == (char *)NULL)
-	return ((regexp *)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 == (regexp *) NULL)
-	FAIL("out of space");
-    (void) bzero(r, sizeof(regexp) + (unsigned)regsize);
-
-    /* Second pass: emit code. */
-    regparse = exp2;
-    regnpar = 1;
-    regcode = r->program;
-    regc(MAGIC);
-    if (reg(0, &flags) == NULL)
-	return ((regexp *) 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;
-	}
-    }
-    free((char*)exp2);
-    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; /* make gcc happy */
-    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 = (char *)NULL;
-
-    /* Pick up the branches, linking them together. */
-    br = regbranch(&flags);
-    if (br == (char *)NULL)
-	return ((char *)NULL);
-    if (ret != (char *)NULL)
-	regtail(ret, br);	/* OPEN -> first. */
-    else
-	ret = br;
-    if (!(flags & HASWIDTH))
-	*flagp &= ~HASWIDTH;
-    *flagp |= flags & SPSTART;
-    while (*regparse == OR_OP) {
-	regparse++;
-	br = regbranch(&flags);
-	if (br == (char *)NULL)
-	    return ((char *)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 != (char *)NULL; br = regnext(br))
-	regoptail(br, ender);
-
-    /* Check for proper termination. */
-    if (paren && *regparse++ != RBRAC) {
-	FAIL("unmatched ()");
-    } else if (!paren && *regparse != '\0') {
-	if (*regparse == RBRAC) {
-	    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 = (char *)NULL;
-    while (*regparse != '\0' && *regparse != OR_OP && *regparse != RBRAC) {
-	latest = regpiece(&flags);
-	if (latest == (char *)NULL)
-	    return ((char *)NULL);
-	*flagp |= flags & HASWIDTH;
-	if (chain == (char *)NULL)	/* First piece. */
-	    *flagp |= flags & SPSTART;
-	else
-	    regtail(chain, latest);
-	chain = latest;
-    }
-    if (chain == (char *)NULL)		/* Loop ran zero times. */
-	regnode(NOTHING);
-
-    return (ret);
-}
-
-/*
- - regpiece - something followed by possible [*]
- *
- * Note that the branching code sequence used for * is 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 short  op;
-  /* register char  *nxt; */
-  int             flags;
-
-  ret = regatom(&flags);
-  if (ret == (char *)NULL)
-    return ((char *)NULL);
-
-  op = *regparse;
-  if (!ISMULT(op)) {
-    *flagp = flags;
-    return (ret);
-  }
-  if (!(flags & HASWIDTH))
-    FAIL("* or + operand could be empty");
-  *flagp = (WORST | SPSTART);
-
-  if(op == ASTERIX)
-  {
-    if (flags & SIMPLE)
-    {
-      reginsert(STAR, ret);
-    }
-    else
-    {
-      /* 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 == PLUS)
-  {
-    /*  Emit a+ as (a&) where & means "self" /Fredrik Hubinette */
-    char *tmp;
-    tmp=regnode(BACK);
-    reginsert(BRANCH, tmp);
-    regtail(ret, tmp);
-    regoptail(tmp, ret);
-    regtail(ret, regnode(BRANCH));
-    regtail(ret, regnode(NOTHING));
-  }
-
-  regparse++;
-  if (ISMULT(*regparse))
-    FAIL("nested * or +");
-
-  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.
- */
-static char *regatom(flagp)
-int            *flagp;
-{
-    register char  *ret;
-    int             flags;
-
-    *flagp = WORST;		/* Tentatively. */
-
-    switch (*regparse++) {
-    case CARET:
-	ret = regnode(BOL);
-	break;
-    case DOLLAR:
-	ret = regnode(EOL);
-	break;
-    case DOT:
-	ret = regnode(ANY);
-	*flagp |= HASWIDTH | SIMPLE;
-	break;
-    case LSHBRAC:
-	ret = regnode(WORDSTART);
-	break;
-    case RSHBRAC:
-	ret = regnode(WORDEND);
-	break;
-    case LSQBRAC:{
-	    register int    class;
-	    register int    classend;
-
-	    if (*regparse == CARET) {	/* Complement of range. */
-		ret = regnode(ANYBUT);
-		regparse++;
-	    } else
-		ret = regnode(ANYOF);
-	    if (*regparse == RSQBRAC || *regparse == '-')
-		regc(*regparse++);
-	    while (*regparse != '\0' && *regparse != RSQBRAC) {
-		if (*regparse == '-') {
-		    regparse++;
-		    if (*regparse == RSQBRAC || *regparse == '\0')
-			regc('-');
-		    else {
-			class = (CHARBITS & *(regparse - 2)) + 1;
-			classend = (CHARBITS & *(regparse));
-			if (class > classend + 1)
-			    FAIL("invalid [] range");
-			for (; class <= classend; class++)
-			    regc(class);
-			regparse++;
-		    }
-		} else
-		    regc(*regparse++);
-	    }
-	    regc('\0');
-	    if (*regparse != RSQBRAC)
-		FAIL("unmatched []");
-	    regparse++;
-	    *flagp |= HASWIDTH | SIMPLE;
-	}
-	break;
-    case LBRAC:
-	ret = reg(1, &flags);
-	if (ret == (char *)NULL)
-	    return ((char *)NULL);
-	*flagp |= flags & (HASWIDTH | SPSTART);
-	break;
-    case '\0':
-    case OR_OP:
-    case RBRAC:
-	FAIL("internal urp");	/* Supposed to be caught earlier. */
-
-    case ASTERIX:
-	FAIL("* follows nothing\n");
-
-    default:{
-	    register int    len;
-	    register short  ender;
-
-	    regparse--;
-	    for (len=0; regparse[len] &&
-	        !(regparse[len]&SPECIAL) && regparse[len] != RSQBRAC; len++) ;
-	    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 *regnode(op)
-char            op;
-{
-    register char  *ret;
-    register char  *ptr;
-
-    ret = regcode;
-    if (ret == &regdummy) {
-	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(b)
-char            b;
-{
-    if (regcode != &regdummy)
-	*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 == &regdummy) {
-	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 == &regdummy)
-	return;
-
-    /* Find last node. */
-    scan = p;
-    for (;;) {
-	temp = regnext(scan);
-	if (temp == (char *)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 == (char *)NULL || p == &regdummy || 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(prog, string)
-register regexp *prog;
-register char  *string;
-{
-    register char  *s;
-
-    /* Be paranoid... */
-    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
-    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 WORDSTART:
-	    if (reginput == regbol)
-		break;
-	    if (*reginput == '\0' ||
-	       ISWORDPART( *(reginput-1) ) || !ISWORDPART( *reginput ) )
-		return (0);
-	    break;
-	case WORDEND:
-	    if (*reginput == '\0')
-		break;
-	    if ( reginput == regbol ||
-	       !ISWORDPART( *(reginput-1) ) || ISWORDPART( *reginput ) )
-		return (0);
-	    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;
-	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 == &regdummy)
-	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
-
-STATIC char    *regprop();
-
-/*
- - 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;
-
-    s = r->program + 1;
-    while (op != END) {		/* While that wasn't END last time... */
-	op = OP(s);
-	printf("%2ld%s", (long)(s - r->program), regprop(s));	/* Where, what. */
-	nxt = regnext(s);
-	if (nxt == (char *)NULL)	/* nxt ptr. */
-	    printf("(0)");
-	else
-	    printf("(%ld)", (long)( (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");
-	p=(char *)NULL;
-	break;
-    }
-    if (p != (char *)NULL)
-	strcat(buf, p);
-    return (buf);
-}
-#endif
-
-/*
- - regsub - perform substitutions after a regexp match
- */
-
-char *regsub(regexp *prog, char *source, char *dest, int n)
-{
-    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 NULL;
-    }
-    if (UCHARAT(prog->program) != MAGIC) {
-	regerror("damaged regexp fed to regsub");
-	return NULL;
-    }
-    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++;
-	    if (--n < 0) {				/* amylaar */
-		regerror("line too long");
-		return NULL;
-	    }
-	    *dst++ = c;
-	} else if (prog->startp[no] != (char *)NULL &&
-		   prog->endp[no] != (char *)NULL) {
-	    len = prog->endp[no] - prog->startp[no];
-	    if ( (n-=len) < 0 ) {		/* amylaar */
-		regerror("line too long");
-		return NULL;
-	    }
-	    strncpy(dst, prog->startp[no], len);
-	    dst += len;
-	    if (len != 0 && *(dst - 1) == '\0') {	/* strncpy hit NUL. */
-		regerror("damaged match string");
-		return NULL;
-	    }
-	}
-    }
-    if (--n < 0) {			/* amylaar */
-    	regerror("line too long");
-    	return NULL;
-    }
-    *dst = '\0';
-    return dst;
-}
-
-
-#if 0	/* Use the local regerror() in ed.c */
-
-void regerror(char *s)
-{
-    fprintf(stderr, "regexp(3): %s", s);
-    exit(1);
-}
-#endif /* 0 */