Aminet 1 (Walnut Creek)/Aminet - June 1993 [Walnut Creek].iso/usenet/sources/volume91/utilitys/less_14z/part06

Internet Message Format | 1991-07-08 | 45KB

Path: news.larc.nasa.gov!amiga-request
From: [e-mail] (Amiga Sources/Binaries Moderator)
Subject: v91i132: Less 1.4Z - text pager, Part06/07
Reply-To: [e-mail] (R. L. Zarling)
Newsgroups: comp.sources.amiga
Message-ID: <[e-mail]>
References: <[e-mail]>
Date: 04 Jul 91 17:28:19 GMT
Approved: [e-mail] (Tad Guy)
X-Mail-Submissions-To: [e-mail]
X-Post-Discussions-To: comp.sys.amiga.misc

Submitted-by: [e-mail] (R. L. Zarling)
Posting-number: Volume 91, Issue 132
Archive-name: utilities/less-1.4z/part06

#!/bin/sh
# This is a shell archive.  Remove anything before this line, then unpack
# it by saving it into a file and typing "sh file".  To overwrite existing
# files, type "sh file -c".  You can also feed this as standard input via
# unshar, or by typing "sh <file", e.g..  If this archive is complete, you
# will see the following message at the end:
#        "End of archive 6 (of 7)."
# Contents:  Less1.4Z/src/regexp.c
# Wrapped by tadguy@ab20 on Thu Jul  4 13:28:16 1991
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
if test -f 'Less1.4Z/src/regexp.c' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'Less1.4Z/src/regexp.c'\"
else
echo shar: Extracting \"'Less1.4Z/src/regexp.c'\" \(41694 characters\)
sed "s/^X//" >'Less1.4Z/src/regexp.c' <<'END_OF_FILE'
X/*
X * regcomp and regexec -- regsub and regerror are elsewhere
X *
X *      Copyright (c) 1986 by University of Toronto.
X *      Written by Henry Spencer.  Not derived from licensed software.
X *
X *      Permission is granted to anyone to use this software for any
X *      purpose on any computer system, and to redistribute it freely,
X *      subject to the following restrictions:
X *
X *      1. The author is not responsible for the consequences of use of
X *              this software, no matter how awful, even if they arise
X *              from defects in it.
X *
X *      2. The origin of this software must not be misrepresented, either
X *              by explicit claim or by omission.
X *
X *      3. Altered versions must be plainly marked as such, and must not
X *              be misrepresented as being the original software.
X *
X * Beware that some of this code is subtly aware of the way operator
X * precedence is structured in regular expressions.  Serious changes in
X * regular-expression syntax might require a total rethink.
X
X * 10/09/88 - This code was altered by Mark R. Rinfret for compatibility
X * with the Amiga. ([e-mail])
X * 6/15/91 - Added ANSI prototypes - Ray Zarling ([e-mail])
X */
X#include <stdio.h>
X#include <string.h>
X#include <stdlib.h>
X#include "regexp.h"
X#include "regmagic.h"
X#ifdef AMIGA
X#define exit(x) quit()
X#define regerror(x) error(x)
Xextern void error ( char *s );
Xextern void quit( void );
X#endif
X
X/* Prototypes for functions defined in regexp.c */
X
Xstatic char *reg __PROTO((int paren,
X                          int *flagp));
Xstatic char *regbranch __PROTO((int *flagp));
Xstatic char *regpiece __PROTO((int *flagp));
Xstatic char *regatom __PROTO((int *flagp));
Xstatic char *regnode __PROTO((char op));
Xstatic void regc __PROTO((char b));
Xstatic void reginsert __PROTO((char op,
X                               char *opnd));
Xstatic void regtail __PROTO((char *p,
X                             char *val));
Xstatic void regoptail __PROTO((char *p,
X                               char *val));
Xstatic int regtry __PROTO((regexp *prog,
X                           char *string));
Xstatic int regmatch __PROTO((char *prog));
Xstatic int regrepeat __PROTO((char *p));
Xstatic char *regnext __PROTO((register char *p));
X
X
X
X/*
X * The "internal use only" fields in regexp.h are present to pass info from
X * compile to execute that permits the execute phase to run lots faster on
X * simple cases.  They are:
X *
X * regstart     char that must begin a match; '\0' if none obvious
X * reganch      is the match anchored (at beginning-of-line only)?
X * regmust      string (pointer into program) that match must include, or NULL
X * regmlen      length of regmust string
X *
X * Regstart and reganch permit very fast decisions on suitable starting points
X * for a match, cutting down the work a lot.  Regmust permits fast rejection
X * of lines that cannot possibly match.  The regmust tests are costly enough
X * that regcomp() supplies a regmust only if the r.e. contains something
X * potentially expensive (at present, the only such thing detected is * or +
X * at the start of the r.e., which can involve a lot of backup).  Regmlen is
X * supplied because the test in regexec() needs it and regcomp() is computing
X * it anyway.
X */
X
X/*
X * Structure for regexp "program".  This is essentially a linear encoding
X * of a nondeterministic finite-state machine (aka syntax charts or
X * "railroad normal form" in parsing technology).  Each node is an opcode
X * plus a "next" pointer, possibly plus an operand.  "Next" pointers of
X * all nodes except BRANCH implement concatenation; a "next" pointer with
X * a BRANCH on both ends of it is connecting two alternatives.  (Here we
X * have one of the subtle syntax dependencies:  an individual BRANCH (as
X * opposed to a collection of them) is never concatenated with anything
X * because of operator precedence.)  The operand of some types of node is
X * a literal string; for others, it is a node leading into a sub-FSM.   In
X * particular, the operand of a BRANCH node is the first node of the branch.
X * (NB this is *not* a tree structure:  the tail of the branch connects
X * to the thing following the set of BRANCHes.)  The opcodes are:
X */
X
X/* definition   number  opnd?   meaning */
X#define END     0       /* no   End of program. */
X#define BOL     1       /* no   Match "" at beginning of line. */
X#define EOL     2       /* no   Match "" at end of line. */
X#define ANY     3       /* no   Match any one character. */
X#define ANYOF   4       /* str  Match any character in this string. */
X#define ANYBUT  5       /* str  Match any character not in this string. */
X#define BRANCH  6       /* node Match this alternative, or the next... */
X#define BACK    7       /* no   Match "", "next" ptr points backward. */
X#define EXACTLY 8       /* str  Match this string. */
X#define NOTHING 9       /* no   Match empty string. */
X#define STAR    10      /* node Match this (simple) thing 0 or more times. */
X#define PLUS    11      /* node Match this (simple) thing 1 or more times. */
X#define OPEN    20      /* no   Mark this point in input as start of #n. */
X                        /*      OPEN+1 is number 1, etc. */
X#define CLOSE   30      /* no   Analogous to OPEN. */
X
X/*
X * Opcode notes:
X *
X * BRANCH       The set of branches constituting a single choice are hooked
X *              together with their "next" pointers, since precedence prevents
X *              anything being concatenated to any individual branch.  The
X *              "next" pointer of the last BRANCH in a choice points to the
X *              thing following the whole choice.  This is also where the
X *              final "next" pointer of each individual branch points; each
X *              branch starts with the operand node of a BRANCH node.
X *
X * BACK         Normal "next" pointers all implicitly point forward; BACK
X *              exists to make loop structures possible.
X *
X * STAR,PLUS    '?', and complex '*' and '+', are implemented as circular
X *              BRANCH structures using BACK.  Simple cases (one character
X *              per match) are implemented with STAR and PLUS for speed
X *              and to minimize recursive plunges.
X *
X * OPEN,CLOSE   ...are numbered at compile time.
X */
X
X/*
X * A node is one char of opcode followed by two chars of "next" pointer.
X * "Next" pointers are stored as two 8-bit pieces, high order first.  The
X * value is a positive offset from the opcode of the node containing it.
X * An operand, if any, simply follows the node.  (Note that much of the
X * code generation knows about this implicit relationship.)
X *
X * Using two bytes for the "next" pointer is vast overkill for most things,
X * but allows patterns to get big without disasters.
X */
X#define OP(p)   (*(p))
X#define NEXT(p) (((*((p)+1)&0377)<<8) + *((p)+2)&0377)
X#define OPERAND(p)      ((p) + 3)
X
X/*
X * See regmagic.h for one further detail of program structure.
X */
X
X
X/*
X * Utility definitions.
X */
X#ifndef CHARBITS
X#define UCHARAT(p)      ((int)*(unsigned char *)(p))
X#else
X#define UCHARAT(p)      ((int)*(p)&CHARBITS)
X#endif
X
X#define FAIL(m) { regerror(m); return(NULL); }
X#define ISMULT(c)       ((c) == '*' || (c) == '+' || (c) == '?')
X#define META    "^$.[()|?+*\\"
X
X/*
X * Flags to be passed up and down.
X */
X#define HASWIDTH        01      /* Known never to match null string. */
X#define SIMPLE          02      /* Simple enough to be STAR/PLUS operand. */
X#define SPSTART         04      /* Starts with * or +. */
X#define WORST           0       /* Worst case. */
X
X/*
X * Global work variables for regcomp().
X */
Xstatic char *regparse;  /* Input-scan pointer. */
Xstatic int regnpar;             /* () count. */
Xstatic char regdummy;
Xstatic char *regcode;           /* Code-emit pointer; ®dummy = don't. */
Xstatic long regsize;            /* Code size. */
X
X/*
X * Forward declarations for regcomp()'s friends.
X */
X#ifndef STATIC
X#define STATIC  static
X#endif
XSTATIC char *reg();
XSTATIC char *regbranch();
XSTATIC char *regpiece();
XSTATIC char *regatom();
XSTATIC char *regnode();
XSTATIC char *regnext();
XSTATIC void regc();
XSTATIC void reginsert();
XSTATIC void regtail();
XSTATIC void regoptail();
X#ifdef STRCSPN
XSTATIC int strcspn();
X#endif
X
X/*
X - regcomp - compile a regular expression into internal code
X *
X * We can't allocate space until we know how big the compiled form will be,
X * but we can't compile it (and thus know how big it is) until we've got a
X * place to put the code.  So we cheat:  we compile it twice, once with code
X * generation turned off and size counting turned on, and once "for real".
X * This also means that we don't allocate space until we are sure that the
X * thing really will compile successfully, and we never have to move the
X * code and thus invalidate pointers into it.   (Note that it has to be in
X * one piece because free() must be able to free it all.)
X *
X * Beware that the optimization-preparation code in here knows about some
X * of the structure of the compiled regexp.
X */
X#ifdef __STDC__
Xregexp *regcomp (char *exp)
X#else
Xregexp *
Xregcomp(exp)
Xchar *exp;
X#endif
X{
X        register regexp *r;
X        register char *scan;
X        register char *longest;
X        register int len;
X        int flags;
X#ifndef AMIGA
X        extern char *calloc();
X#endif
X
X        if (exp == NULL)
X                FAIL("NULL argument");
X
X        /* First pass: determine size, legality. */
X        regparse = exp;
X        regnpar = 1;
X        regsize = 0L;
X        regcode = ®dummy;
X        regc(MAGIC);
X        if (reg(0, &flags) == NULL)
X                return(NULL);
X
X        /* Small enough for pointer-storage convention? */
X        if (regsize >= 32767L)          /* Probably could be 65535L. */
X                FAIL("regexp too big");
X
X        /* Allocate space. */
X        r = (regexp *)calloc(1,sizeof(regexp) + (unsigned)regsize);
X        if (r == NULL)
X                FAIL("out of space");
X
X        /* Second pass: emit code. */
X        regparse = exp;
X        regnpar = 1;
X        regcode = r->program;
X        regc(MAGIC);
X        if (reg(0, &flags) == NULL)
X                return(NULL);
X
X        /* Dig out information for optimizations. */
X        r->regstart = '\0';     /* Worst-case defaults. */
X        r->reganch = 0;
X        r->regmust = NULL;
X        r->regmlen = 0;
X        scan = r->program+1;                    /* First BRANCH. */
X        if (OP(regnext(scan)) == END) {         /* Only one top-level choice. */
X                scan = OPERAND(scan);
X
X                /* Starting-point info. */
X                if (OP(scan) == EXACTLY)
X                        r->regstart = *OPERAND(scan);
X                else if (OP(scan) == BOL)
X                        r->reganch++;
X
X                /*
X                 * If there's something expensive in the r.e., find the
X                 * longest literal string that must appear and make it the
X                 * regmust.  Resolve ties in favor of later strings, since
X                 * the regstart check works with the beginning of the r.e.
X                 * and avoiding duplication strengthens checking.  Not a
X                 * strong reason, but sufficient in the absence of others.
X                 */
X                if (flags&SPSTART) {
X                        longest = NULL;
X                        len = 0;
X                        for (; scan != NULL; scan = regnext(scan))
X                                if (OP(scan) == EXACTLY && strlen(OPERAND(scan)) >= len) {
X                                        longest = OPERAND(scan);
X                                        len = strlen(OPERAND(scan));
X                                }
X                        r->regmust = longest;
X                        r->regmlen = len;
X                }
X        }
X
X        return(r);
X}
X
X/*
X - reg - regular expression, i.e. main body or parenthesized thing
X *
X * Caller must absorb opening parenthesis.
X *
X * Combining parenthesis handling with the base level of regular expression
X * is a trifle forced, but the need to tie the tails of the branches to what
X * follows makes it hard to avoid.
X */
X#ifdef __STDC__
Xstatic char *reg (int paren, int *flagp)
X#else
Xstatic char *
Xreg(paren, flagp)
Xint paren;                      /* Parenthesized? */
Xint *flagp;
X#endif
X{
X        register char *ret;
X        register char *br;
X        register char *ender;
X        register int parno;
X        int flags;
X
X        *flagp = HASWIDTH;      /* Tentatively. */
X
X        /* Make an OPEN node, if parenthesized. */
X        if (paren) {
X                if (regnpar >= NSUBEXP)
X                        FAIL("too many ()");
X                parno = regnpar;
X                regnpar++;
X                ret = regnode(OPEN+parno);
X        } else
X                ret = NULL;
X
X        /* Pick up the branches, linking them together. */
X        br = regbranch(&flags);
X        if (br == NULL)
X                return(NULL);
X        if (ret != NULL)
X                regtail(ret, br);       /* OPEN -> first. */
X        else
X                ret = br;
X        if (!(flags&HASWIDTH))
X                *flagp &= ~HASWIDTH;
X        *flagp |= flags&SPSTART;
X        while (*regparse == '|') {
X                regparse++;
X                br = regbranch(&flags);
X                if (br == NULL)
X                        return(NULL);
X                regtail(ret, br);       /* BRANCH -> BRANCH. */
X                if (!(flags&HASWIDTH))
X                        *flagp &= ~HASWIDTH;
X                *flagp |= flags&SPSTART;
X        }
X
X        /* Make a closing node, and hook it on the end. */
X        ender = regnode((paren) ? CLOSE+parno : END);
X        regtail(ret, ender);
X
X        /* Hook the tails of the branches to the closing node. */
X        for (br = ret; br != NULL; br = regnext(br))
X                regoptail(br, ender);
X
X        /* Check for proper termination. */
X        if (paren && *regparse++ != ')') {
X                FAIL("unmatched ()");
X        } else if (!paren && *regparse != '\0') {
X                if (*regparse == ')') {
X                        FAIL("unmatched ()");
X                } else
X                        FAIL("junk on end");    /* "Can't happen". */
X                /* NOTREACHED */
X        }
X
X        return(ret);
X}
X
X/*
X - regbranch - one alternative of an | operator
X *
X * Implements the concatenation operator.
X */
X#ifdef __STDC__
Xstatic char *regbranch (int *flagp)
X#else
Xstatic char *
Xregbranch(flagp)
Xint *flagp;
X#endif
X{
X        register char *ret;
X        register char *chain;
X        register char *latest;
X        int flags;
X
X        *flagp = WORST;         /* Tentatively. */
X
X        ret = regnode(BRANCH);
X        chain = NULL;
X        while (*regparse != '\0' && *regparse != '|' && *regparse != ')') {
X                latest = regpiece(&flags);
X                if (latest == NULL)
X                        return(NULL);
X                *flagp |= flags&HASWIDTH;
X                if (chain == NULL)      /* First piece. */
X                        *flagp |= flags&SPSTART;
X                else
X                        regtail(chain, latest);
X                chain = latest;
X        }
X        if (chain == NULL)      /* Loop ran zero times. */
X                (void) regnode(NOTHING);
X
X        return(ret);
X}
X
X/*
X - regpiece - something followed by possible [*+?]
X *
X * Note that the branching code sequences used for ? and the general cases
X * of * and + are somewhat optimized:   they use the same NOTHING node as
X * both the endmarker for their branch list and the body of the last branch.
X * It might seem that this node could be dispensed with entirely, but the
X * endmarker role is not redundant.
X */
X#ifdef __STDC__
Xstatic char *regpiece (int *flagp)
X#else
Xstatic char *
Xregpiece(flagp)
Xint *flagp;
X#endif
X{
X        register char *ret;
X        register char op;
X        register char *next;
X        int flags;
X
X        ret = regatom(&flags);
X        if (ret == NULL)
X                return(NULL);
X
X        op = *regparse;
X        if (!ISMULT(op)) {
X                *flagp = flags;
X                return(ret);
X        }
X
X        if (!(flags&HASWIDTH) && op != '?')
X                FAIL("*+ operand could be empty");
X        *flagp = (op != '+') ? (WORST|SPSTART) : (WORST|HASWIDTH);
X
X        if (op == '*' && (flags&SIMPLE))
X                reginsert(STAR, ret);
X        else if (op == '*') {
X                /* Emit x* as (x&|), where & means "self". */
X                reginsert(BRANCH, ret);                 /* Either x */
X                regoptail(ret, regnode(BACK));          /* and loop */
X                regoptail(ret, ret);                    /* back */
X                regtail(ret, regnode(BRANCH));          /* or */
X                regtail(ret, regnode(NOTHING));         /* null. */
X        } else if (op == '+' && (flags&SIMPLE))
X                reginsert(PLUS, ret);
X        else if (op == '+') {
X                /* Emit x+ as x(&|), where & means "self". */
X                next = regnode(BRANCH);                 /* Either */
X                regtail(ret, next);
X                regtail(regnode(BACK), ret);            /* loop back */
X                regtail(next, regnode(BRANCH));         /* or */
X                regtail(ret, regnode(NOTHING));         /* null. */
X        } else if (op == '?') {
X                /* Emit x? as (x|) */
X                reginsert(BRANCH, ret);                 /* Either x */
X                regtail(ret, regnode(BRANCH));          /* or */
X                next = regnode(NOTHING);                /* null. */
X                regtail(ret, next);
X                regoptail(ret, next);
X        }
X        regparse++;
X        if (ISMULT(*regparse))
X                FAIL("nested *?+");
X
X        return(ret);
X}
X
X/*
X - regatom - the lowest level
X *
X * Optimization:  gobbles an entire sequence of ordinary characters so that
X * it can turn them into a single node, which is smaller to store and
X * faster to run.  Backslashed characters are exceptions, each becoming a
X * separate node; the code is simpler that way and it's not worth fixing.
X */
X#ifdef __STDC__
Xstatic char *regatom (int *flagp)
X#else
Xstatic char *
Xregatom(flagp)
Xint *flagp;
X#endif
X{
X        register char *ret;
X        int flags;
X
X        *flagp = WORST;         /* Tentatively. */
X
X        switch (*regparse++) {
X        case '^':
X                ret = regnode(BOL);
X                break;
X        case '$':
X                ret = regnode(EOL);
X                break;
X        case '.':
X                ret = regnode(ANY);
X                *flagp |= HASWIDTH|SIMPLE;
X                break;
X        case '[': {
X                        register int class;
X                        register int classend;
X
X                        if (*regparse == '^') { /* Complement of range. */
X                                ret = regnode(ANYBUT);
X                                regparse++;
X                        } else
X                                ret = regnode(ANYOF);
X                        if (*regparse == ']' || *regparse == '-')
X                                regc(*regparse++);
X                        while (*regparse != '\0' && *regparse != ']') {
X                                if (*regparse == '-') {
X                                        regparse++;
X                                        if (*regparse == ']' || *regparse == '\0')
X                                                regc('-');
X                                        else {
X                                                class = UCHARAT(regparse-2)+1;
X                                                classend = UCHARAT(regparse);
X                                                if (class > classend+1)
X                                                        FAIL("invalid [] range");
X                                                for (; class <= classend; class++)
X                                                        regc(class);
X                                                regparse++;
X                                        }
X                                } else
X                                        regc(*regparse++);
X                        }
X                        regc('\0');
X                        if (*regparse != ']')
X                                FAIL("unmatched []");
X                        regparse++;
X                        *flagp |= HASWIDTH|SIMPLE;
X                }
X                break;
X        case '(':
X                ret = reg(1, &flags);
X                if (ret == NULL)
X                        return(NULL);
X                *flagp |= flags&(HASWIDTH|SPSTART);
X                break;
X        case '\0':
X        case '|':
X        case ')':
X                FAIL("internal urp");   /* Supposed to be caught earlier. */
X                break;
X        case '?':
X        case '+':
X        case '*':
X                FAIL("?+* follows nothing");
X                break;
X        case '\\':
X                if (*regparse == '\0')
X                        FAIL("trailing \\");
X                ret = regnode(EXACTLY);
X                regc(*regparse++);
X                regc('\0');
X                *flagp |= HASWIDTH|SIMPLE;
X                break;
X        default: {
X                        register int len;
X                        register char ender;
X
X                        regparse--;
X                        len = strcspn(regparse, META);
X                        if (len <= 0)
X                                FAIL("internal disaster");
X                        ender = *(regparse+len);
X                        if (len > 1 && ISMULT(ender))
X                                len--;          /* Back off clear of ?+* operand. */
X                        *flagp |= HASWIDTH;
X                        if (len == 1)
X                                *flagp |= SIMPLE;
X                        ret = regnode(EXACTLY);
X                        while (len > 0) {
X                                regc(*regparse++);
X                                len--;
X                        }
X                        regc('\0');
X                }
X                break;
X        }
X
X        return(ret);
X}
X
X/*
X - regnode - emit a node
X */
X#ifdef __STDC__
Xstatic char *regnode (char op)
X#else
Xstatic char *                   /* Location. */
Xregnode(op)
Xchar op;
X#endif
X{
X        register char *ret;
X        register char *ptr;
X
X        ret = regcode;
X        if (ret == ®dummy) {
X                regsize += 3;
X                return(ret);
X        }
X
X        ptr = ret;
X        *ptr++ = op;
X        *ptr++ = '\0';          /* Null "next" pointer. */
X        *ptr++ = '\0';
X        regcode = ptr;
X
X        return(ret);
X}
X
X/*
X - regc - emit (if appropriate) a byte of code
X */
X#ifdef __STDC__
Xstatic void regc (char b)
X#else
Xstatic void
Xregc(b)
Xchar b;
X#endif
X{
X        if (regcode != ®dummy)
X                *regcode++ = b;
X        else
X                regsize++;
X}
X
X/*
X - reginsert - insert an operator in front of already-emitted operand
X *
X * Means relocating the operand.
X */
X#ifdef __STDC__
Xstatic void reginsert (char op, char *opnd)
X#else
Xstatic void
Xreginsert(op, opnd)
Xchar op;
Xchar *opnd;
X#endif
X{
X        register char *src;
X        register char *dst;
X        register char *place;
X
X        if (regcode == ®dummy) {
X                regsize += 3;
X                return;
X        }
X
X        src = regcode;
X        regcode += 3;
X        dst = regcode;
X        while (src > opnd)
X                *--dst = *--src;
X
X        place = opnd;           /* Op node, where operand used to be. */
X        *place++ = op;
X        *place++ = '\0';
X        *place++ = '\0';
X}
X
X/*
X - regtail - set the next-pointer at the end of a node chain
X */
X#ifdef __STDC__
Xstatic void regtail (char *p, char *val)
X#else
Xstatic void
Xregtail(p, val)
Xchar *p;
Xchar *val;
X#endif
X{
X        register char *scan;
X        register char *temp;
X        register int offset;
X
X        if (p == ®dummy)
X                return;
X
X        /* Find last node. */
X        scan = p;
X        for (;;) {
X                temp = regnext(scan);
X                if (temp == NULL)
X                        break;
X                scan = temp;
X        }
X
X        if (OP(scan) == BACK)
X                offset = scan - val;
X        else
X                offset = val - scan;
X        *(scan+1) = (offset>>8)&0377;
X        *(scan+2) = offset&0377;
X}
X
X/*
X - regoptail - regtail on operand of first argument; nop if operandless
X */
X#ifdef __STDC__
Xstatic void regoptail (char *p, char *val)
X#else
Xstatic void
Xregoptail(p, val)
Xchar *p;
Xchar *val;
X#endif
X{
X        /* "Operandless" and "op != BRANCH" are synonymous in practice. */
X        if (p == NULL || p == ®dummy || OP(p) != BRANCH)
X                return;
X        regtail(OPERAND(p), val);
X}
X
X/*
X * regexec and friends
X */
X
X/*
X * Global work variables for regexec().
X */
Xstatic char *reginput;  /* String-input pointer. */
Xstatic char *regbol;            /* Beginning of input, for ^ check. */
Xstatic char **regstartp;        /* Pointer to startp array. */
Xstatic char **regendp;  /* Ditto for endp. */
X
X/*
X * Forwards.
X */
XSTATIC int regtry();
XSTATIC int regmatch();
XSTATIC int regrepeat();
X
X#ifdef DEBUG
Xint regnarrate = 0;
Xvoid regdump();
XSTATIC char *regprop();
X#endif
X
X/*
X - regexec - match a regexp against a string
X */
X#ifdef __STDC__
Xint regexec (register regexp *prog, register char *string)
X#else
Xint
Xregexec(prog, string)
Xregister regexp *prog;
Xregister char *string;
X#endif
X{
X        register char *s;
X        extern char *strchr();
X
X        /* Be paranoid... */
X        if (prog == NULL || string == NULL) {
X                regerror("NULL parameter");
X                return(0);
X        }
X
X        /* Check validity of program. */
X        if (UCHARAT(prog->program) != MAGIC) {
X                regerror("corrupted program");
X                return(0);
X        }
X
X        /* If there is a "must appear" string, look for it. */
X        if (prog->regmust != NULL) {
X                s = string;
X                while ((s = strchr(s, prog->regmust[0])) != NULL) {
X                        if (strncmp(s, prog->regmust, prog->regmlen) == 0)
X                                break;  /* Found it. */
X                        s++;
X                }
X                if (s == NULL)  /* Not present. */
X                        return(0);
X        }
X
X        /* Mark beginning of line for ^ . */
X        regbol = string;
X
X        /* Simplest case:  anchored match need be tried only once. */
X        if (prog->reganch)
X                return(regtry(prog, string));
X
X        /* Messy cases:  unanchored match. */
X        s = string;
X        if (prog->regstart != '\0')
X                /* We know what char it must start with. */
X                while ((s = strchr(s, prog->regstart)) != NULL) {
X                        if (regtry(prog, s))
X                                return(1);
X                        s++;
X                }
X        else
X                /* We don't -- general case. */
X                do {
X                        if (regtry(prog, s))
X                                return(1);
X                } while (*s++ != '\0');
X
X        /* Failure. */
X        return(0);
X}
X
X/*
X - regtry - try match at specific point
X */
X#ifdef __STDC__
Xstatic int regtry (regexp *prog, char *string)
X#else
Xstatic int                      /* 0 failure, 1 success */
Xregtry(prog, string)
Xregexp *prog;
Xchar *string;
X#endif
X{
X        register int i;
X        register char **sp;
X        register char **ep;
X
X        reginput = string;
X        regstartp = prog->startp;
X        regendp = prog->endp;
X
X        sp = prog->startp;
X        ep = prog->endp;
X        for (i = NSUBEXP; i > 0; i--) {
X                *sp++ = NULL;
X                *ep++ = NULL;
X        }
X        if (regmatch(prog->program + 1)) {
X                prog->startp[0] = string;
X                prog->endp[0] = reginput;
X                return(1);
X        } else
X                return(0);
X}
X
X/*
X - regmatch - main matching routine
X *
X * Conceptually the strategy is simple:  check to see whether the current
X * node matches, call self recursively to see whether the rest matches,
X * and then act accordingly.  In practice we make some effort to avoid
X * recursion, in particular by going through "ordinary" nodes (that don't
X * need to know whether the rest of the match failed) by a loop instead of
X * by recursion.
X */
X#ifdef __STDC__
Xstatic int regmatch (char *prog)
X#else
Xstatic int                      /* 0 failure, 1 success */
Xregmatch(prog)
Xchar *prog;
X#endif
X{
X        register char *scan;    /* Current node. */
X        char *next;             /* Next node. */
X        extern char *strchr();
X
X        scan = prog;
X#ifdef DEBUG
X        if (scan != NULL && regnarrate)
X                fprintf(stderr, "%s(\n", regprop(scan));
X#endif
X        while (scan != NULL) {
X#ifdef DEBUG
X                if (regnarrate)
X                        fprintf(stderr, "%s...\n", regprop(scan));
X#endif
X                next = regnext(scan);
X
X                switch (OP(scan)) {
X                case BOL:
X                        if (reginput != regbol)
X                                return(0);
X                        break;
X                case EOL:
X                        if (*reginput != '\0')
X                                return(0);
X                        break;
X                case ANY:
X                        if (*reginput == '\0')
X                                return(0);
X                        reginput++;
X                        break;
X                case EXACTLY: {
X                                register int len;
X                                register char *opnd;
X
X                                opnd = OPERAND(scan);
X                                /* Inline the first character, for speed. */
X                                if (*opnd != *reginput)
X                                        return(0);
X                                len = strlen(opnd);
X                                if (len > 1 && strncmp(opnd, reginput, len) != 0)
X                                        return(0);
X                                reginput += len;
X                        }
X                        break;
X                case ANYOF:
X                        if (*reginput == '\0' || strchr(OPERAND(scan), *reginput) == NULL)
X                                return(0);
X                        reginput++;
X                        break;
X                case ANYBUT:
X                        if (*reginput == '\0' || strchr(OPERAND(scan), *reginput) != NULL)
X                                return(0);
X                        reginput++;
X                        break;
X                case NOTHING:
X                        break;
X                case BACK:
X                        break;
X                case OPEN+1:
X                case OPEN+2:
X                case OPEN+3:
X                case OPEN+4:
X                case OPEN+5:
X                case OPEN+6:
X                case OPEN+7:
X                case OPEN+8:
X                case OPEN+9: {
X                                register int no;
X                                register char *save;
X
X                                no = OP(scan) - OPEN;
X                                save = reginput;
X
X                                if (regmatch(next)) {
X                                        /*
X                                         * Don't set startp if some later
X                                         * invocation of the same parentheses
X                                         * already has.
X                                         */
X                                        if (regstartp[no] == NULL)
X                                                regstartp[no] = save;
X                                        return(1);
X                                } else
X                                        return(0);
X                        }
X                        break;
X                case CLOSE+1:
X                case CLOSE+2:
X                case CLOSE+3:
X                case CLOSE+4:
X                case CLOSE+5:
X                case CLOSE+6:
X                case CLOSE+7:
X                case CLOSE+8:
X                case CLOSE+9: {
X                                register int no;
X                                register char *save;
X
X                                no = OP(scan) - CLOSE;
X                                save = reginput;
X
X                                if (regmatch(next)) {
X                                        /*
X                                         * Don't set endp if some later
X                                         * invocation of the same parentheses
X                                         * already has.
X                                         */
X                                        if (regendp[no] == NULL)
X                                                regendp[no] = save;
X                                        return(1);
X                                } else
X                                        return(0);
X                        }
X                        break;
X                case BRANCH: {
X                                register char *save;
X
X                                if (OP(next) != BRANCH)         /* No choice. */
X                                        next = OPERAND(scan);   /* Avoid recursion. */
X                                else {
X                                        do {
X                                                save = reginput;
X                                                if (regmatch(OPERAND(scan)))
X                                                        return(1);
X                                                reginput = save;
X                                                scan = regnext(scan);
X                                        } while (scan != NULL && OP(scan) == BRANCH);
X                                        return(0);
X                                        /* NOTREACHED */
X                                }
X                        }
X                        break;
X                case STAR:
X                case PLUS: {
X                                register char nextch;
X                                register int no;
X                                register char *save;
X                                register int min;
X
X                                /*
X                                 * Lookahead to avoid useless match attempts
X                                 * when we know what character comes next.
X                                 */
X                                nextch = '\0';
X                                if (OP(next) == EXACTLY)
X                                        nextch = *OPERAND(next);
X                                min = (OP(scan) == STAR) ? 0 : 1;
X                                save = reginput;
X                                no = regrepeat(OPERAND(scan));
X                                while (no >= min) {
X                                        /* If it could work, try it. */
X                                        if (nextch == '\0' || *reginput == nextch)
X                                                if (regmatch(next))
X                                                        return(1);
X                                        /* Couldn't or didn't -- back up. */
X                                        no--;
X                                        reginput = save + no;
X                                }
X                                return(0);
X                        }
X                        break;
X                case END:
X                        return(1);      /* Success! */
X                        break;
X                default:
X                        regerror("memory corruption");
X                        return(0);
X                        break;
X                }
X
X                scan = next;
X        }
X
X        /*
X         * We get here only if there's trouble -- normally "case END" is
X         * the terminating point.
X         */
X        regerror("corrupted pointers");
X        return(0);
X}
X
X/*
X - regrepeat - repeatedly match something simple, report how many
X */
X#ifdef __STDC__
Xstatic int regrepeat (char *p)
X#else
Xstatic int
Xregrepeat(p)
Xchar *p;
X#endif
X{
X        register int count = 0;
X        register char *scan;
X        register char *opnd;
X
X        scan = reginput;
X        opnd = OPERAND(p);
X        switch (OP(p)) {
X        case ANY:
X                count = strlen(scan);
X                scan += count;
X                break;
X        case EXACTLY:
X                while (*opnd == *scan) {
X                        count++;
X                        scan++;
X                }
X                break;
X        case ANYOF:
X                while (*scan != '\0' && strchr(opnd, *scan) != NULL) {
X                        count++;
X                        scan++;
X                }
X                break;
X        case ANYBUT:
X                while (*scan != '\0' && strchr(opnd, *scan) == NULL) {
X                        count++;
X                        scan++;
X                }
X                break;
X        default:                /* Oh dear.  Called inappropriately. */
X                regerror("internal foulup");
X                count = 0;      /* Best compromise. */
X                break;
X        }
X        reginput = scan;
X
X        return(count);
X}
X
X/*
X - regnext - dig the "next" pointer out of a node
X */
X#ifdef __STDC__
Xstatic char *regnext (register char *p)
X#else
Xstatic char *
Xregnext(p)
Xregister char *p;
X#endif
X{
X        register int offset;
X
X        if (p == ®dummy)
X                return(NULL);
X
X        offset = NEXT(p);
X        if (offset == 0)
X                return(NULL);
X
X        if (OP(p) == BACK)
X                return(p-offset);
X        else
X                return(p+offset);
X}
X
X#ifdef DEBUG
X
XSTATIC char *regprop();
X
X/*
X - regdump - dump a regexp onto stdout in vaguely comprehensible form
X */
Xvoid
Xregdump(r)
Xregexp *r;
X{
X        register char *s;
X        register char op = EXACTLY;     /* Arbitrary non-END op. */
X        register char *next;
X        extern char *strchr();
X
X
X        s = r->program + 1;
X        while (op != END) {     /* While that wasn't END last time... */
X                op = OP(s);
X                printf("%2d%s", s-r->program, regprop(s));      /* Where, what. */
X                next = regnext(s);
X                if (next == NULL)               /* Next ptr. */
X                        printf("(0)");
X                else
X                        printf("(%d)", (s-r->program)+(next-s));
X                s += 3;
X                if (op == ANYOF || op == ANYBUT || op == EXACTLY) {
X                        /* Literal string, where present. */
X                        while (*s != '\0') {
X                                putchar(*s);
X                                s++;
X                        }
X                        s++;
X                }
X                putchar('\n');
X        }
X
X        /* Header fields of interest. */
X        if (r->regstart != '\0')
X                printf("start `%c' ", r->regstart);
X        if (r->reganch)
X                printf("anchored ");
X        if (r->regmust != NULL)
X                printf("must have \"%s\"", r->regmust);
X        printf("\n");
X}
X
X/*
X - regprop - printable representation of opcode
X */
Xstatic char *
Xregprop(op)
Xchar *op;
X{
X        register char *p;
X        static char buf[50];
X
X        (void) strcpy(buf, ":");
X
X        switch (OP(op)) {
X        case BOL:
X                p = "BOL";
X                break;
X        case EOL:
X                p = "EOL";
X                break;
X        case ANY:
X                p = "ANY";
X                break;
X        case ANYOF:
X                p = "ANYOF";
X                break;
X        case ANYBUT:
X                p = "ANYBUT";
X                break;
X        case BRANCH:
X                p = "BRANCH";
X                break;
X        case EXACTLY:
X                p = "EXACTLY";
X                break;
X        case NOTHING:
X                p = "NOTHING";
X                break;
X        case BACK:
X                p = "BACK";
X                break;
X        case END:
X                p = "END";
X                break;
X        case OPEN+1:
X        case OPEN+2:
X        case OPEN+3:
X        case OPEN+4:
X        case OPEN+5:
X        case OPEN+6:
X        case OPEN+7:
X        case OPEN+8:
X        case OPEN+9:
X                sprintf(buf+strlen(buf), "OPEN%d", OP(op)-OPEN);
X                p = NULL;
X                break;
X        case CLOSE+1:
X        case CLOSE+2:
X        case CLOSE+3:
X        case CLOSE+4:
X        case CLOSE+5:
X        case CLOSE+6:
X        case CLOSE+7:
X        case CLOSE+8:
X        case CLOSE+9:
X                sprintf(buf+strlen(buf), "CLOSE%d", OP(op)-CLOSE);
X                p = NULL;
X                break;
X        case STAR:
X                p = "STAR";
X                break;
X        case PLUS:
X                p = "PLUS";
X                break;
X        default:
X                regerror("corrupted opcode");
X                break;
X        }
X        if (p != NULL)
X                (void) strcat(buf, p);
X        return(buf);
X}
X#endif
X
X/*
X * The following is provided for those people who do not have strcspn() in
X * their C libraries.   They should get off their butts and do something
X * about it; at least one public-domain implementation of those (highly
X * useful) string routines has been published on Usenet.
X */
X#ifdef STRCSPN
X/*
X * strcspn - find length of initial segment of s1 consisting entirely
X * of characters not from s2
X */
X
Xstatic int
Xstrcspn(s1, s2)
Xchar *s1;
Xchar *s2;
X{
X        register char *scan1;
X        register char *scan2;
X        register int count;
X
X        count = 0;
X        for (scan1 = s1; *scan1 != '\0'; scan1++) {
X                for (scan2 = s2; *scan2 != '\0';)       /* ++ moved down. */
X                        if (*scan1 == *scan2++)
X                                return(count);
X                count++;
X        }
X        return(count);
X}
X#endif
END_OF_FILE
if test 41694 -ne `wc -c <'Less1.4Z/src/regexp.c'`; then
    echo shar: \"'Less1.4Z/src/regexp.c'\" unpacked with wrong size!
fi
# end of 'Less1.4Z/src/regexp.c'
fi
echo shar: End of archive 6 \(of 7\).
cp /dev/null ark6isdone
MISSING=""
for I in 1 2 3 4 5 6 7 ; do
    if test ! -f ark${I}isdone ; then
    MISSING="${MISSING} ${I}"
    fi
done
if test "${MISSING}" = "" ; then
    echo You have unpacked all 7 archives.
    rm -f ark[1-9]isdone
else
    echo You still need to unpack the following archives:
    echo "        " ${MISSING}
fi
##  End of shell archive.
exit 0
--
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