amiga-request@ab20.larc.nasa.gov (Amiga Sources/Binaries Moderator) (02/27/91)
Submitted-by: eyal@echo.canberra.edu.au (Eyal Lebedinsky)
Posting-number: Volume 91, Issue 026
Archive-name: news/vn-res1.1/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 6)."
# Contents: regexp.c
# Wrapped by tadguy@ab20 on Tue Feb 26 19:28:49 1991
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
if test -f 'regexp.c' -a "${1}" != "-c" ; then
echo shar: Will not clobber existing file \"'regexp.c'\"
else
echo shar: Extracting \"'regexp.c'\" \(28412 characters\)
sed "s/^X//" >'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 * The third parameter to regexec was added by Martin C. Atkins.
X * Andy Tanenbaum also made some changes.
X */
X
X#include <stdio.h>
X#include "regexp.h"
X
X#ifdef amiga
X#undef putchar
X#define putchar ttputc
Xextern char pr_buf[];
Xextern ttputc ();
X#endif
X
X/*
X * The first byte of the regexp internal "program" is actually this magic
X * number; the start node begins in the second byte.
X */
X#define MAGIC 0234
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
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();
XSTATIC int strcspn();
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 */
Xregexp *
Xregcomp(exp)
Xchar *exp;
X{
X register regexp *r;
X register char *scan;
X register char *longest;
X register int len;
X int flags;
X extern char *malloc();
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 *)malloc(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 */
Xstatic char *
Xreg(paren, flagp)
Xint paren; /* Parenthesized? */
Xint *flagp;
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 */
Xstatic char *
Xregbranch(flagp)
Xint *flagp;
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 */
Xstatic char *
Xregpiece(flagp)
Xint *flagp;
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 */
Xstatic char *
Xregatom(flagp)
Xint *flagp;
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 */
Xstatic char * /* Location. */
Xregnode(op)
Xchar op;
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 */
Xstatic void
Xregc(b)
Xchar b;
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 */
Xstatic void
Xreginsert(op, opnd)
Xchar op;
Xchar *opnd;
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 */
Xstatic void
Xregtail(p, val)
Xchar *p;
Xchar *val;
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 */
Xstatic void
Xregoptail(p, val)
Xchar *p;
Xchar *val;
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 */
Xint
Xregexec(prog, string, bolflag)
Xregister regexp *prog;
Xregister char *string;
Xint bolflag;
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 if(bolflag)
X regbol = string;
X else
X regbol = NULL;
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 */
Xstatic int /* 0 failure, 1 success */
Xregtry(prog, string)
Xregexp *prog;
Xchar *string;
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 */
Xstatic int /* 0 failure, 1 success */
Xregmatch(prog)
Xchar *prog;
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 */
Xstatic int
Xregrepeat(p)
Xchar *p;
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 */
Xstatic char *
Xregnext(p)
Xregister char *p;
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#ifdef amiga
X sprintf(pr_buf,"%2d%s", s-r->program, regprop(s)); /* Where, what. */
X tputs(pr_buf,1,ttputc);
X#else
X printf("%2d%s", s-r->program, regprop(s)); /* Where, what. */
X#endif
X next = regnext(s);
X if (next == NULL) { /* Next ptr. */
X#ifdef amiga
X sprintf(pr_buf,"(0)");
X tputs(pr_buf,1,ttputc);
X#else
X printf("(0)");
X#endif
X } else {
X#ifdef amiga
X sprintf(pr_buf,"(%d)", (s-r->program)+(next-s));
X tputs(pr_buf,1,ttputc);
X#else
X printf("(%d)", (s-r->program)+(next-s));
X#endif
X }
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#ifdef amiga
X sprintf(pr_buf,"start `%c' ", r->regstart);
X tputs(pr_buf,1,ttputc);
X#else
X printf("start `%c' ", r->regstart);
X#endif
X }
X if (r->reganch) {
X#ifdef amiga
X sprintf(pr_buf,"anchored ");
X tputs(pr_buf,1,ttputc);
X#else
X printf("anchored ");
X#endif
X }
X if (r->regmust != NULL) {
X#ifdef amiga
X sprintf(pr_buf,"must have \"%s\"", r->regmust);
X tputs(pr_buf,1,ttputc);
X#else
X printf("must have \"%s\"", r->regmust);
X#endif
X }
X#ifdef amiga
X sprintf(pr_buf,"\n");
X tputs(pr_buf,1,ttputc);
X#else
X printf("\n");
X#endif
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/*
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}
END_OF_FILE
if test 28412 -ne `wc -c <'regexp.c'`; then
echo shar: \"'regexp.c'\" unpacked with wrong size!
fi
# end of 'regexp.c'
fi
echo shar: End of archive 6 \(of 6\).
cp /dev/null ark6isdone
MISSING=""
for I in 1 2 3 4 5 6 ; do
if test ! -f ark${I}isdone ; then
MISSING="${MISSING} ${I}"
fi
done
if test "${MISSING}" = "" ; then
echo You have unpacked all 6 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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