/* vi:ts=4:sw=4
* NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE
*
* This is NOT the original regular expression code as written by
* Henry Spencer. This code has been modified specifically for use
* with the VIM editor, and should not be used apart from compiling
* VIM. If you want a good regular expression library, get the
* original code. The copyright notice that follows is from the
* original.
*
* Furthermore, this code is modified to work on Japanese letters
* for use with the JVim editor.
*
* NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE
*
*
* regcomp and regexec -- regsub and regerror are elsewhere
*
* Copyright (c) 1986 by University of Toronto.
* Written by Henry Spencer. Not derived from licensed software.
*
* Permission is granted to anyone to use this software for any
* purpose on any computer system, and to redistribute it freely,
* subject to the following restrictions:
*
* 1. The author is not responsible for the consequences of use of
* this software, no matter how awful, even if they arise
* from defects in it.
*
* 2. The origin of this software must not be misrepresented, either
* by explicit claim or by omission.
*
* 3. Altered versions must be plainly marked as such, and must not
* be misrepresented as being the original software.
*
* 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.
*
* $Log: regexp.c,v $
* Revision 1.2 88/04/28 08:09:45 tony
* First modification of the regexp library. Added an external variable
* 'reg_ic' which can be set to indicate that case should be ignored.
* Added a new parameter to regexec() to indicate that the given string
* comes from the beginning of a line and is thus eligible to match
* 'beginning-of-line'.
*
* Revisions by Olaf 'Rhialto' Seibert, rhialto@cs.kun.nl:
* Changes for vi: (the semantics of several things were rather different)
* - Added lexical analyzer, because in vi magicness of characters
* is rather difficult, and may change over time.
* - Added support for \< \> \1-\9 and ~
* - Left some magic stuff in, but only backslashed: \| \+
* - * and \+ still work after \) even though they shouldn't.
*/
#include "vim.h"
#include "globals.h"
#include "proto.h"
#include "jp.h"
#undef DEBUG
#include <stdio.h>
#include "regexp.h"
#include "regmagic.h"
/*
* The "internal use only" fields in regexp.h are present to pass info from
* compile to execute that permits the execute phase to run lots faster on
* simple cases. They are:
*
* regstart char that must begin a match; '\0' if none obvious
* reganch is the match anchored (at beginning-of-line only)?
* regmust string (pointer into program) that match must include, or NULL
* regmlen length of regmust string
*
* Regstart and reganch permit very fast decisions on suitable starting points
* for a match, cutting down the work a lot. Regmust permits fast rejection
* of lines that cannot possibly match. The regmust tests are costly enough
* that regcomp() supplies a regmust only if the r.e. contains something
* potentially expensive (at present, the only such thing detected is * or +
* at the start of the r.e., which can involve a lot of backup). Regmlen is
* supplied because the test in regexec() needs it and regcomp() is computing
* it anyway.
*/
/*
* Structure for regexp "program". This is essentially a linear encoding
* of a nondeterministic finite-state machine (aka syntax charts or
* "railroad normal form" in parsing technology). Each node is an opcode
* plus a "next" pointer, possibly plus an operand. "Next" pointers of
* all nodes except BRANCH implement concatenation; a "next" pointer with
* a BRANCH on both ends of it is connecting two alternatives. (Here we
* have one of the subtle syntax dependencies: an individual BRANCH (as
* opposed to a collection of them) is never concatenated with anything
* because of operator precedence.) The operand of some types of node is
* a literal string; for others, it is a node leading into a sub-FSM. In
* particular, the operand of a BRANCH node is the first node of the branch.
* (NB this is *not* a tree structure: the tail of the branch connects
* to the thing following the set of BRANCHes.) The opcodes are:
*/
/* definition number opnd? meaning */
#define END 0 /* no End of program. */
#define BOL 1 /* no Match "" at beginning of line. */
#define EOL 2 /* no Match "" at end of line. */
#define ANY 3 /* no Match any one character. */
#define ANYOF 4 /* str Match any character in this string. */
#define ANYBUT 5 /* str Match any character not in this
* string. */
#define BRANCH 6 /* node Match this alternative, or the
* next... */
#define BACK 7 /* no Match "", "next" ptr points backward. */
#define EXACTLY 8 /* str Match this string. */
#define NOTHING 9 /* no Match empty string. */
#define STAR 10 /* node Match this (simple) thing 0 or more
* times. */
#define PLUS 11 /* node Match this (simple) thing 1 or more
* times. */
#define BOW 12 /* no Match "" after [^a-zA-Z0-9_] */
#define EOW 13 /* no Match "" at [^a-zA-Z0-9_] */
#define MOPEN 20 /* no Mark this point in input as start of
* #n. */
/* MOPEN+1 is number 1, etc. */
#define MCLOSE 30 /* no Analogous to MOPEN. */
#define BACKREF 40 /* node Match same string again \1-\9 */
#define Magic(x) ((x)|('\\'<<8))
/*
* Opcode notes:
*
* BRANCH The set of branches constituting a single choice are hooked
* together with their "next" pointers, since precedence prevents
* anything being concatenated to any individual branch. The
* "next" pointer of the last BRANCH in a choice points to the
* thing following the whole choice. This is also where the
* final "next" pointer of each individual branch points; each
* branch starts with the operand node of a BRANCH node.
*
* BACK Normal "next" pointers all implicitly point forward; BACK
* exists to make loop structures possible.
*
* STAR,PLUS '?', and complex '*' and '+', are implemented as circular
* BRANCH structures using BACK. Simple cases (one character
* per match) are implemented with STAR and PLUS for speed
* and to minimize recursive plunges.
*
* MOPEN,MCLOSE ...are numbered at compile time.
*/
/*
* A node is one char of opcode followed by two chars of "next" pointer.
* "Next" pointers are stored as two 8-bit pieces, high order first. The
* value is a positive offset from the opcode of the node containing it.
* An operand, if any, simply follows the node. (Note that much of the
* code generation knows about this implicit relationship.)
*
* Using two bytes for the "next" pointer is vast overkill for most things,
* but allows patterns to get big without disasters.
*/
#define OP(p) (*(p))
#define NEXT(p) (((*((p)+1)&0377)<<8) + (*((p)+2)&0377))
#define OPERAND(p) ((p) + 3)
/*
* See regmagic.h for one further detail of program structure.
*/
/*
* Utility definitions.
*/
#ifndef CHARBITS
#define UCHARAT(p) ((int)*(unsigned char *)(p))
#else
#define UCHARAT(p) ((int)*(p)&CHARBITS)
#endif
#define FAIL(m) { emsg(m); return NULL; }
static int ismult __ARGS((int));
#ifdef DEBUG
void regdump __ARGS((regexp *));
#endif
static int
ismult(c)
int c;
{
return (c == Magic('*') || c == Magic('+') || c == Magic('?'));
}
/*
* Flags to be passed up and down.
*/
#define HASWIDTH 01 /* Known never to match null string. */
#define SIMPLE 02 /* Simple enough to be STAR/PLUS operand. */
#define SPSTART 04 /* Starts with * or +. */
#define WORST 0 /* Worst case. */
/*
* The following supports the ability to ignore case in searches.
*/
int reg_ic = 0; /* set by callers to ignore case */
/*
* mkup - convert to upper case IF we're doing caseless compares
*/
#define mkup(c) (reg_ic ? TO_UPPER(c) : (c))
/*
* The following allows empty REs, meaning "the same as the previous RE".
* per the ed(1) manual.
*/
/* #define EMPTY_RE */ /* this is done outside of regexp */
#ifdef EMPTY_RE
char *reg_prev_re;
#endif
#define TILDE
#ifdef TILDE
char *reg_prev_sub;
#endif
/*
* This if for vi's "magic" mode. If magic is false, only ^$\ are magic.
*/
int reg_magic = 1;
/*
* Global work variables for regcomp().
*/
static unsigned char *regparse; /* Input-scan pointer. */
static int regnpar; /* () count. */
static char regdummy;
static char *regcode; /* Code-emit pointer; ®dummy = don't. */
static long regsize; /* Code size. */
static char **regendp; /* Ditto for endp. */
/*
* META contains all characters that may be magic, except '^' and '$'.
* This depends on the configuration options TILDE, BACKREF.
* (could be done simpler for compilers that know string concatenation)
*/
#ifdef TILDE
# ifdef BACKREF
static char META[] = ".[()|?+*<>~123456789";
# else
static char META[] = ".[()|?+*<>~";
# endif
#else
# ifdef BACKREF
static char META[] = ".[()|?+*<>123456789";
# else
static char META[] = ".[()|?+*<>";
# endif
#endif
/*
* Forward declarations for regcomp()'s friends.
*/
static void initchr __ARGS((unsigned char *));
static int getchr __ARGS((void));
static int peekchr __ARGS((void));
#define PeekChr() curchr /* shortcut only when last action was peekchr() */
static int curchr;
static void skipchr __ARGS((void));
static void ungetchr __ARGS((void));
static char *reg __ARGS((int, int *));
static char *regbranch __ARGS((int *));
static char *regpiece __ARGS((int *));
static char *regatom __ARGS((int *));
static char *regnode __ARGS((int));
static char *regnext __ARGS((char *));
static void regc __ARGS((int));
static void unregc __ARGS((void));
static void reginsert __ARGS((int, char *));
static void regtail __ARGS((char *, char *));
static void regoptail __ARGS((char *, char *));
#ifdef JP
static void regjp();
static char *strjpchr();
#endif
#undef STRCSPN
#ifdef STRCSPN
static int strcspn __ARGS((const char *, const char *));
#endif
static int cstrncmp __ARGS((char *, char *, int));
#ifdef GENERAL
# define alloc(x) malloc(x)
# undef free
#endif
/*
- regcomp - compile a regular expression into internal code
*
* We can't allocate space until we know how big the compiled form will be,
* but we can't compile it (and thus know how big it is) until we've got a
* place to put the code. So we cheat: we compile it twice, once with code
* generation turned off and size counting turned on, and once "for real".
* This also means that we don't allocate space until we are sure that the
* thing really will compile successfully, and we never have to move the
* code and thus invalidate pointers into it. (Note that it has to be in
* one piece because free() must be able to free it all.)
*
* Beware that the optimization-preparation code in here knows about some
* of the structure of the compiled regexp.
*/
regexp *
regcomp(exp)
char *exp;
{
register regexp *r;
register char *scan;
register char *longest;
register int len;
int flags;
/* extern char *malloc(); */
if (exp == NULL) {
FAIL(e_null);
}
#ifdef EMPTY_RE /* this is done outside of regexp */
if (*exp == '\0') {
if (reg_prev_re) {
exp = reg_prev_re;
} else {
FAIL(e_noprevre);
}
}
#endif
/* First pass: determine size, legality. */
initchr((unsigned char *)exp);
regnpar = 1;
regsize = 0L;
regcode = ®dummy;
regendp = NULL;
regc(MAGIC);
if (reg(0, &flags) == NULL)
return NULL;
/* Small enough for pointer-storage convention? */
if (regsize >= 32767L) /* Probably could be 65535L. */
FAIL(e_toolong);
/* Allocate space. */
r = (regexp *) alloc((unsigned) (sizeof(regexp) + regsize));
if (r == NULL)
FAIL(e_outofmem);
#ifdef EMPTY_RE /* this is done outside of regexp */
if (exp != reg_prev_re) {
free(reg_prev_re);
if ((reg_prev_re = alloc(strlen(exp) + 1)))
strcpy(reg_prev_re, exp);
}
#endif
/* Second pass: emit code. */
initchr((unsigned char *)exp);
regnpar = 1;
regcode = r->program;
regendp = r->endp;
regc(MAGIC);
if (reg(0, &flags) == NULL) {
free(r);
return NULL;
}
/* Dig out information for optimizations. */
r->regstart = '\0'; /* Worst-case defaults. */
r->reganch = 0;
r->regmust = NULL;
r->regmlen = 0;
scan = r->program + 1; /* First BRANCH. */
if (OP(regnext(scan)) == END) { /* Only one top-level choice. */
scan = OPERAND(scan);
/* Starting-point info. */
if (OP(scan) == EXACTLY)
r->regstart = *OPERAND(scan);
else if (OP(scan) == BOL)
r->reganch++;
/*
* If there's something expensive in the r.e., find the longest
* literal string that must appear and make it the regmust. Resolve
* ties in favor of later strings, since the regstart check works
* with the beginning of the r.e. and avoiding duplication
* strengthens checking. Not a strong reason, but sufficient in the
* absence of others.
*/
if (flags & SPSTART) {
longest = NULL;
len = 0;
for (; scan != NULL; scan = regnext(scan))
if (OP(scan) == EXACTLY && strlen(OPERAND(scan)) >= (size_t)len) {
longest = OPERAND(scan);
len = strlen(OPERAND(scan));
}
r->regmust = longest;
r->regmlen = len;
}
}
#ifdef DEBUG
regdump(r);
#endif
return r;
}
/*
- reg - regular expression, i.e. main body or parenthesized thing
*
* Caller must absorb opening parenthesis.
*
* Combining parenthesis handling with the base level of regular expression
* is a trifle forced, but the need to tie the tails of the branches to what
* follows makes it hard to avoid.
*/
static char *
reg(paren, flagp)
int paren; /* Parenthesized? */
int *flagp;
{
register char *ret;
register char *br;
register char *ender;
register int parno = 0;
int flags;
*flagp = HASWIDTH; /* Tentatively. */
/* Make an MOPEN node, if parenthesized. */
if (paren) {
if (regnpar >= NSUBEXP)
FAIL(e_toombra);
parno = regnpar;
regnpar++;
ret = regnode((char)(MOPEN + parno));
if (regendp)
regendp[parno] = NULL; /* haven't seen the close paren yet */
} else
ret = NULL;
/* Pick up the branches, linking them together. */
br = regbranch(&flags);
if (br == NULL)
return NULL;
if (ret != NULL)
regtail(ret, br); /* MOPEN -> first. */
else
ret = br;
if (!(flags & HASWIDTH))
*flagp &= ~HASWIDTH;
*flagp |= flags & SPSTART;
while (peekchr() == Magic('|')) {
skipchr();
br = regbranch(&flags);
if (br == NULL)
return NULL;
regtail(ret, br); /* BRANCH -> BRANCH. */
if (!(flags & HASWIDTH))
*flagp &= ~HASWIDTH;
*flagp |= flags & SPSTART;
}
/* Make a closing node, and hook it on the end. */
ender = regnode((char)((paren) ? MCLOSE + parno : END));
regtail(ret, ender);
/* Hook the tails of the branches to the closing node. */
for (br = ret; br != NULL; br = regnext(br))
regoptail(br, ender);
/* Check for proper termination. */
if (paren && getchr() != Magic(')')) {
FAIL(e_toombra);
} else if (!paren && peekchr() != '\0') {
if (PeekChr() == Magic(')')) {
FAIL(e_toomket);
} else
FAIL(e_trailing);/* "Can't happen". */
/* NOTREACHED */
}
/*
* Here we set the flag allowing back references to this set of
* parentheses.
*/
if (paren && regendp)
regendp[parno] = ender; /* have seen the close paren */
return ret;
}
/*
- regbranch - one alternative of an | operator
*
* Implements the concatenation operator.
*/
static char *
regbranch(flagp)
int *flagp;
{
register char *ret;
register char *chain;
register char *latest;
int flags;
*flagp = WORST; /* Tentatively. */
ret = regnode(BRANCH);
chain = NULL;
while (peekchr() != '\0' && PeekChr() != Magic('|') && PeekChr() != Magic(')')) {
latest = regpiece(&flags);
if (latest == NULL)
return NULL;
*flagp |= flags & HASWIDTH;
if (chain == NULL) /* First piece. */
*flagp |= flags & SPSTART;
else
regtail(chain, latest);
chain = latest;
}
if (chain == NULL) /* Loop ran zero times. */
(void) regnode(NOTHING);
return ret;
}
/*
- regpiece - something followed by possible [*+?]
*
* Note that the branching code sequences used for ? and the general cases
* of * and + are somewhat optimized: they use the same NOTHING node as
* both the endmarker for their branch list and the body of the last branch.
* It might seem that this node could be dispensed with entirely, but the
* endmarker role is not redundant.
*/
static char *
regpiece(flagp)
int *flagp;
{
register char *ret;
register int op;
register char *next;
int flags;
ret = regatom(&flags);
if (ret == NULL)
return NULL;
op = peekchr();
if (!ismult(op)) {
*flagp = flags;
return ret;
}
if (!(flags & HASWIDTH) && op != Magic('?'))
FAIL("*+ operand could be empty");
*flagp = (op != Magic('+')) ? (WORST | SPSTART) : (WORST | HASWIDTH);
if (op == Magic('*') && (flags & SIMPLE))
reginsert(STAR, ret);
else if (op == Magic('*')) {
/* 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 == Magic('+') && (flags & SIMPLE))
reginsert(PLUS, ret);
else if (op == Magic('+')) {
/* Emit x+ as x(&|), where & means "self". */
next = regnode(BRANCH); /* Either */
regtail(ret, next);
regtail(regnode(BACK), ret); /* loop back */
regtail(next, regnode(BRANCH)); /* or */
regtail(ret, regnode(NOTHING)); /* null. */
} else if (op == Magic('?')) {
/* Emit x? as (x|) */
reginsert(BRANCH, ret); /* Either x */
regtail(ret, regnode(BRANCH)); /* or */
next = regnode(NOTHING);/* null. */
regtail(ret, next);
regoptail(ret, next);
}
skipchr();
if (ismult(peekchr()))
FAIL("Nested *?+");
return ret;
}
/*
- regatom - the lowest level
*
* Optimization: gobbles an entire sequence of ordinary characters so that
* it can turn them into a single node, which is smaller to store and
* faster to run.
*/
static char *
regatom(flagp)
int *flagp;
{
register char *ret;
int flags;
*flagp = WORST; /* Tentatively. */
switch (getchr()) {
case Magic('^'):
ret = regnode(BOL);
break;
case Magic('$'):
ret = regnode(EOL);
break;
case Magic('<'):
ret = regnode(BOW);
break;
case Magic('>'):
ret = regnode(EOW);
break;
case Magic('.'):
ret = regnode(ANY);
*flagp |= HASWIDTH | SIMPLE;
break;
case Magic('['):{
/*
* In a character class, different parsing rules apply.
* Not even \ is special anymore, nothing is.
*/
if (*regparse == '^') { /* Complement of range. */
ret = regnode(ANYBUT);
regparse++;
} else
ret = regnode(ANYOF);
if (*regparse == ']' || *regparse == '-')
regc(*regparse++);
while (*regparse != '\0' && *regparse != ']') {
if (*regparse == '-') {
regparse++;
if (*regparse == ']' || *regparse == '\0')
regc('-');
else {
register int class;
register int classend;
#ifdef JP
if (IsKanji(*(regparse - 2)))
class = ((*(regparse - 3) & 0x7f) << 8 ) |
(*(regparse - 2) & 0x7f);
else
#endif
class = UCHARAT(regparse - 2) + 1;
#ifdef JP
if (IsKanji(*regparse))
{
classend = ((*regparse & 0x7f) << 8 ) |
(*(regparse + 1) & 0x7f);
regparse ++;
}
else
#endif
classend = UCHARAT(regparse);
#ifdef JP
if (classend - class > 256)
FAIL(e_invrange);
#endif
if (class > classend + 1)
FAIL(e_invrange);
#ifdef JP
if (class & 0xff00)
for (; class <= classend; class++)
regjp(((char)(class >> 8)) | 0x80,
(class & 0xff) | 0x80);
else
#endif
for (; class <= classend; class++)
regc((char)class);
regparse++;
}
} else {
if (*regparse == '\\' && regparse[1])
regparse++;
#ifdef JP
if (IsKanji(*regparse))
{ u_char c;
c = *regparse++;
regjp(c, *regparse++);
}
else
#endif
regc(*regparse++);
}
}
regc('\0');
if (*regparse != ']')
FAIL(e_toomsbra);
skipchr(); /* let's be friends with the lexer again */
*flagp |= HASWIDTH | SIMPLE;
}
break;
case Magic('('):
ret = reg(1, &flags);
if (ret == NULL)
return NULL;
*flagp |= flags & (HASWIDTH | SPSTART);
break;
case '\0':
case Magic('|'):
case Magic(')'):
FAIL(e_internal); /* Supposed to be caught earlier. */
/* break; Not Reached */
case Magic('?'):
case Magic('+'):
case Magic('*'):
FAIL("?+* follows nothing");
/* break; Not Reached */
#ifdef TILDE
case Magic('~'): /* previous substitute pattern */
if (reg_prev_sub) {
register char *p;
ret = regnode(EXACTLY);
p = reg_prev_sub;
while (*p) {
regc(*p++);
}
regc('\0');
if (p - reg_prev_sub) {
*flagp |= HASWIDTH;
if ((p - reg_prev_sub) == 1)
*flagp |= SIMPLE;
}
} else
FAIL(e_nopresub);
break;
#endif
#ifdef BACKREF
case Magic('1'):
case Magic('2'):
case Magic('3'):
case Magic('4'):
case Magic('5'):
case Magic('6'):
case Magic('7'):
case Magic('8'):
case Magic('9'): {
int refnum;
ungetchr();
refnum = getchr() - Magic('0');
/*
* Check if the back reference is legal. We use the parentheses
* pointers to mark encountered close parentheses, but this
* is only available in the second pass. Checking opens is
* always possible.
* Should also check that we don't refer to something that
* is repeated (+*?): what instance of the repetition should
* we match? TODO.
*/
if (refnum < regnpar &&
(regendp == NULL || regendp[refnum] != NULL))
ret = regnode(BACKREF + refnum);
else
FAIL("Illegal back reference");
}
break;
#endif
default:{
register int len;
int chr;
ungetchr();
len = 0;
ret = regnode(EXACTLY);
while ((chr = peekchr()) != '\0' && (chr < Magic(0)))
{
#ifdef JP
if (IsKanji(chr))
regjp(chr, regparse[1]);
else
#endif
regc(chr);
skipchr();
len++;
}
#ifdef DEBUG
if (len == 0)
FAIL("Unexpected magic character; check META.");
#endif
/*
* If there is a following *, \+ or \? we need the character
* in front of it as a single character operand
*/
if (len > 1 && ismult(chr))
{
unregc(); /* Back off of *+? operand */
ungetchr(); /* and put it back for next time */
--len;
}
regc('\0');
*flagp |= HASWIDTH;
if (len == 1)
*flagp |= SIMPLE;
}
break;
}
return ret;
}
/*
- regnode - emit a node
*/
static char * /* Location. */
regnode(op)
int op;
{
register char *ret;
register char *ptr;
ret = regcode;
if (ret == ®dummy) {
regsize += 3;
return ret;
}
ptr = ret;
*ptr++ = op;
*ptr++ = '\0'; /* Null "next" pointer. */
*ptr++ = '\0';
regcode = ptr;
return ret;
}
/*
- regc - emit (if appropriate) a byte of code
*/
static void
regc(b)
int b;
{
if (regcode != ®dummy)
*(u_char *)regcode++ = b;
else
regsize++;
}
#ifdef JP
static void
regjp(b, k)
int b;
u_char k;
{
if (regcode != ®dummy)
{
*(u_char *)regcode++ = b;
*(u_char *)regcode++ = k;
}
else
regsize++;
}
#endif
/*
- unregc - take back (if appropriate) a byte of code
*/
static void
unregc()
{
if (regcode != ®dummy)
#ifdef JP
{
if (IsKanji(* --regcode))
regcode--;
}
#else
regcode--;
#endif
else
regsize--;
}
/*
- reginsert - insert an operator in front of already-emitted operand
*
* Means relocating the operand.
*/
static void
reginsert(op, opnd)
int op;
char *opnd;
{
register char *src;
register char *dst;
register char *place;
if (regcode == ®dummy) {
regsize += 3;
return;
}
src = regcode;
regcode += 3;
dst = regcode;
while (src > opnd)
*--dst = *--src;
place = opnd; /* Op node, where operand used to be. */
*place++ = op;
*place++ = '\0';
*place = '\0';
}
/*
- regtail - set the next-pointer at the end of a node chain
*/
static void
regtail(p, val)
char *p;
char *val;
{
register char *scan;
register char *temp;
register int offset;
if (p == ®dummy)
return;
/* Find last node. */
scan = p;
for (;;) {
temp = regnext(scan);
if (temp == NULL)
break;
scan = temp;
}
if (OP(scan) == BACK)
offset = (int)(scan - val);
else
offset = (int)(val - scan);
*(scan + 1) = (char) ((offset >> 8) & 0377);
*(scan + 2) = (char) (offset & 0377);
}
/*
- regoptail - regtail on operand of first argument; nop if operandless
*/
static void
regoptail(p, val)
char *p;
char *val;
{
/* "Operandless" and "op != BRANCH" are synonymous in practice. */
if (p == NULL || p == ®dummy || OP(p) != BRANCH)
return;
regtail(OPERAND(p), val);
}
/*
- getchr() - get the next character from the pattern. We know about
* magic and such, so therefore we need a lexical analyzer.
*/
/* static int curchr; */
static int prevchr;
static int nextchr; /* used for ungetchr() */
static void
initchr(str)
unsigned char *str;
{
regparse = str;
curchr = prevchr = nextchr = -1;
}
static int
peekchr()
{
if (curchr < 0) {
switch (curchr = regparse[0]) {
case '.':
case '*':
/* case '+':*/
/* case '?':*/
case '[':
case '~':
if (reg_magic)
curchr = Magic(curchr);
break;
case '^':
/* ^ is only magic as the very first character */
if (prevchr < 0)
curchr = Magic('^');
break;
case '$':
/* $ is only magic as the very last character */
if (!regparse[1])
curchr = Magic('$');
break;
case '\\':
regparse++;
if (regparse[0] == NUL)
curchr = '\\'; /* trailing '\' */
else if (strchr(META, regparse[0]))
{
/*
* META contains everything that may be magic sometimes, except
* ^ and $ ("\^" and "\$" are never magic).
* We now fetch the next character and toggle its magicness.
* Therefore, \ is so meta-magic that it is not in META.
*/
curchr = -1;
peekchr();
curchr ^= Magic(0);
}
else
{
/*
* Next character can never be (made) magic?
* Then backslashing it won't do anything.
*/
curchr = regparse[0];
}
break;
}
}
return curchr;
}
static void
skipchr()
{
#ifdef JP
if (IsKanji(*regparse))
regparse += 2;
else
#endif
regparse++;
prevchr = curchr;
curchr = nextchr; /* use previously unget char, or -1 */
nextchr = -1;
}
static int
getchr()
{
int chr;
chr = peekchr();
skipchr();
return chr;
}
/*
* put character back. Works only once!
*/
static void
ungetchr()
{
nextchr = curchr;
curchr = prevchr;
/*
* Backup regparse as well; not because we will use what it points at,
* but because skipchr() will bump it again.
*/
#ifdef JP
if (IsKanji(curchr))
{
nextchr = -1;
regparse-= 2;
}
else
#endif
regparse--;
}
/*
* 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 __ARGS((regexp *, char *));
static int regmatch __ARGS((char *));
static int regrepeat __ARGS((char *));
#ifdef DEBUG
int regnarrate = 1;
/* void regdump __ARGS((regexp *)); */
static char *regprop __ARGS((char *));
#endif
/*
- regexec - match a regexp against a string
*/
int
regexec(prog, string, at_bol)
register regexp *prog;
register char *string;
int at_bol;
{
register char *s;
/* Be paranoid... */
if (prog == NULL || string == NULL) {
emsg(e_null);
return 0;
}
/* Check validity of program. */
if (UCHARAT(prog->program) != MAGIC) {
emsg(e_re_corr);
return 0;
}
/* If there is a "must appear" string, look for it. */
if (prog->regmust != NULL) {
s = string;
while ((s = cstrchr(s, prog->regmust[0])) != NULL) {
if (cstrncmp(s, prog->regmust, prog->regmlen) == 0)
break; /* Found it. */
#ifdef JP
if (IsKanji(*s))
s += 2;
else
#endif
s++;
}
if (s == NULL) /* Not present. */
return 0;
}
/* Mark beginning of line for ^ . */
if (at_bol)
regbol = string; /* is possible to match bol */
else
regbol = NULL; /* we aren't there, so don't match it */
/* Simplest case: anchored match need be tried only once. */
if (prog->reganch)
return regtry(prog, string);
/* Messy cases: unanchored match. */
s = string;
if (prog->regstart != '\0')
/* We know what char it must start with. */
while ((s = cstrchr(s, prog->regstart)) != NULL) {
if (regtry(prog, s))
return 1;
#ifdef JP
if (IsKanji(*s))
s += 2;
else
#endif
s++;
}
else
/* We don't -- general case. */
do {
if (regtry(prog, s))
return 1;
if (*s == '\0')
break;
#ifdef JP
if (IsKanji(*s))
s += 2;
else
#endif
s ++;
} while (1);
/* Failure. */
return 0;
}
/*
- regtry - try match at specific point
*/
static int /* 0 failure, 1 success */
regtry(prog, string)
regexp *prog;
char *string;
{
register int i;
register char **sp;
register char **ep;
reginput = string;
regstartp = prog->startp;
regendp = prog->endp;
sp = prog->startp;
ep = prog->endp;
for (i = NSUBEXP; i > 0; i--) {
*sp++ = NULL;
*ep++ = NULL;
}
if (regmatch(prog->program + 1)) {
prog->startp[0] = string;
prog->endp[0] = reginput;
return 1;
} else
return 0;
}
/*
- regmatch - main matching routine
*
* Conceptually the strategy is simple: check to see whether the current
* node matches, call self recursively to see whether the rest matches,
* and then act accordingly. In practice we make some effort to avoid
* recursion, in particular by going through "ordinary" nodes (that don't
* need to know whether the rest of the match failed) by a loop instead of
* by recursion.
*/
static int /* 0 failure, 1 success */
regmatch(prog)
char *prog;
{
register char *scan; /* Current node. */
char *next; /* Next node. */
scan = prog;
#ifdef DEBUG
if (scan != NULL && regnarrate)
fprintf(stderr, "%s(\n", regprop(scan));
#endif
while (scan != NULL) {
#ifdef DEBUG
if (regnarrate) {
fprintf(stderr, "%s...\n", regprop(scan));
}
#endif
next = regnext(scan);
switch (OP(scan)) {
case BOL:
if (reginput != regbol)
return 0;
break;
case EOL:
if (*reginput != '\0')
return 0;
break;
case BOW: /* \<word; reginput points to w */
#define isidchar(x) (isalnum((u_char) x) || ((x) == '_'))
if (!reginput[0])
return 0;
#ifdef JP
if (IsKanji(reginput[0]))
{
int sclass; /* sclass == JPC_KIGOU : Symbol */
if (! (sclass = jpcls(reginput[0], reginput[1])) || sclass == JPC_KIGOU)
return 0;
if (reginput != regbol && IsKanji(reginput[-1]) &&
sclass == jpcls(reginput[-2], reginput[-1]))
return 0;
break;
}
#endif
if (reginput != regbol && isidchar(reginput[-1]))
return 0;
if (!isidchar(reginput[0]))
return 0;
break;
case EOW: /* word\>; reginput points after d */
if (reginput == regbol)
return 0;
#ifdef JP
if (IsKanji(reginput[-1]))
{
int sclass;
if (! (sclass = jpcls(reginput[-2], reginput[-1]))
|| sclass == JPC_KIGOU)
return 0;
if (IsKanji(reginput[0])
&& sclass == jpcls(reginput[0], reginput[1]))
return 0;
break;
}
#endif
if (!isidchar(reginput[-1]))
return 0;
if (reginput[0] && isidchar(reginput[0]))
return 0;
break;
case ANY:
if (*reginput == '\0')
return 0;
#ifdef JP
if (IsKanji(*reginput))
reginput += 2;
else
#endif
reginput++;
break;
case EXACTLY:{
register int len;
register char *opnd;
opnd = OPERAND(scan);
/* Inline the first character, for speed. */
if (mkup(*opnd) != mkup(*reginput))
return 0;
len = strlen(opnd);
if (len > 1 && cstrncmp(opnd, reginput, len) != 0)
return 0;
reginput += len;
}
break;
case ANYOF:
#ifdef JP
if (*reginput == '\0' ||
strjpchr(OPERAND(scan), *reginput, *(reginput + 1)) == NULL)
#else
if (*reginput == '\0' || strchr(OPERAND(scan), *reginput) == NULL)
#endif
return 0;
#ifdef JP
if (IsKanji(*reginput))
reginput += 2;
else
#endif
reginput++;
break;
case ANYBUT:
#ifdef JP
if (*reginput == '\0' ||
strjpchr(OPERAND(scan), *reginput, *(reginput + 1)) != NULL)
#else
if (*reginput == '\0' || strchr(OPERAND(scan), *reginput) != NULL)
#endif
return 0;
#ifdef JP
if (IsKanji(*reginput))
reginput += 2;
else
#endif
reginput++;
break;
case NOTHING:
break;
case BACK:
break;
case MOPEN + 1:
case MOPEN + 2:
case MOPEN + 3:
case MOPEN + 4:
case MOPEN + 5:
case MOPEN + 6:
case MOPEN + 7:
case MOPEN + 8:
case MOPEN + 9:{
register int no;
register char *save;
no = OP(scan) - MOPEN;
save = regstartp[no];
regstartp[no] = reginput; /* Tentatively */
#ifdef DEBUG
printf("MOPEN %d pre @'%s' ('%s' )'%s'\n",
no, save,
regstartp[no]? regstartp[no] : "NULL",
regendp[no]? regendp[no] : "NULL");
#endif
if (regmatch(next)) {
#ifdef DEBUG
printf("MOPEN %d post @'%s' ('%s' )'%s'\n",
no, save,
regstartp[no]? regstartp[no] : "NULL",
regendp[no]? regendp[no] : "NULL");
#endif
return 1;
}
regstartp[no] = save; /* We were wrong... */
return 0;
}
/* break; Not Reached */
case MCLOSE + 1:
case MCLOSE + 2:
case MCLOSE + 3:
case MCLOSE + 4:
case MCLOSE + 5:
case MCLOSE + 6:
case MCLOSE + 7:
case MCLOSE + 8:
case MCLOSE + 9:{
register int no;
register char *save;
no = OP(scan) - MCLOSE;
save = regendp[no];
regendp[no] = reginput; /* Tentatively */
#ifdef DEBUG
printf("MCLOSE %d pre @'%s' ('%s' )'%s'\n",
no, save,
regstartp[no]? regstartp[no] : "NULL",
regendp[no]? regendp[no] : "NULL");
#endif
if (regmatch(next)) {
#ifdef DEBUG
printf("MCLOSE %d post @'%s' ('%s' )'%s'\n",
no, save,
regstartp[no]? regstartp[no] : "NULL",
regendp[no]? regendp[no] : "NULL");
#endif
return 1;
}
regendp[no] = save; /* We were wrong... */
return 0;
}
/* break; Not Reached */
#ifdef BACKREF
case BACKREF + 1:
case BACKREF + 2:
case BACKREF + 3:
case BACKREF + 4:
case BACKREF + 5:
case BACKREF + 6:
case BACKREF + 7:
case BACKREF + 8:
case BACKREF + 9:{
register int no;
int len;
no = OP(scan) - BACKREF;
if (regendp[no] != NULL) {
len = (int)(regendp[no] - regstartp[no]);
if (cstrncmp(regstartp[no], reginput, len) != 0)
return 0;
reginput += len;
} else {
/*emsg("backref to 0-repeat");*/
/*return 0;*/
}
}
break;
#endif
case BRANCH:{
register char *save;
if (OP(next) != BRANCH) /* No choice. */
next = OPERAND(scan); /* Avoid recursion. */
else {
do {
save = reginput;
if (regmatch(OPERAND(scan)))
return 1;
reginput = save;
scan = regnext(scan);
} while (scan != NULL && OP(scan) == BRANCH);
return 0;
/* NOTREACHED */
}
}
break;
case STAR:
case PLUS:{
register char nextch;
register int no;
register char *save;
register int min;
/*
* Lookahead to avoid useless match attempts when we know
* what character comes next.
*/
nextch = '\0';
if (OP(next) == EXACTLY)
nextch = mkup(*OPERAND(next));
min = (OP(scan) == STAR) ? 0 : 1;
save = reginput;
no = regrepeat(OPERAND(scan));
while (no >= min) {
/* If it could work, try it. */
if (nextch == '\0' || mkup(*reginput) == nextch)
if (regmatch(next))
return 1;
/* Couldn't or didn't -- back up. */
no--;
reginput = save + no;
#ifdef JP
if (IsKanji(*reginput))
{
no --;
reginput --;
}
#endif
}
return 0;
}
/* break; Not Reached */
case END:
return 1; /* Success! */
/* break; Not Reached */
default:
emsg(e_re_corr);
return 0;
/* break; Not Reached */
}
scan = next;
}
/*
* We get here only if there's trouble -- normally "case END" is the
* terminating point.
*/
emsg(e_re_corr);
return 0;
}
/*
- regrepeat - repeatedly match something simple, report how many
*/
static int
regrepeat(p)
char *p;
{
register int count = 0;
register char *scan;
register char *opnd;
scan = reginput;
opnd = OPERAND(p);
switch (OP(p)) {
case ANY:
count = strlen(scan);
scan += count;
break;
case EXACTLY:
#ifdef JP
if (IsKanji(*opnd))
while (*opnd == *scan && *(opnd + 1) == *(scan + 1)) {
count+=2;
scan +=2;
}
else
#endif
while (mkup(*opnd) == mkup(*scan)) {
count++;
scan++;
}
break;
case ANYOF:
#ifdef JP
while (*scan != '\0' &&
strjpchr(opnd, *scan, *(scan + 1)) != NULL)
if (IsKanji(*scan))
{
count += 2;
scan += 2;
}
else
{
count ++;
scan ++;
}
#else
while (*scan != '\0' && strchr(opnd, *scan) != NULL) {
count++;
scan++;
}
#endif
break;
case ANYBUT:
#ifdef JP
while (*scan != '\0' &&
strjpchr(opnd, *scan, *(scan + 1)) == NULL)
if (IsKanji(*scan))
{
count += 2;
scan += 2;
}
else
{
count ++;
scan ++;
}
#else
while (*scan != '\0' && strchr(opnd, *scan) == NULL) {
count++;
scan++;
}
#endif
break;
default: /* Oh dear. Called inappropriately. */
emsg(e_re_corr);
count = 0; /* Best compromise. */
break;
}
reginput = scan;
return count;
}
/*
- regnext - dig the "next" pointer out of a node
*/
static char *
regnext(p)
register char *p;
{
register int offset;
if (p == ®dummy)
return NULL;
offset = NEXT(p);
if (offset == 0)
return NULL;
if (OP(p) == BACK)
return p - offset;
else
return p + offset;
}
#ifdef DEBUG
/*
- regdump - dump a regexp onto stdout in vaguely comprehensible form
*/
void
regdump(r)
regexp *r;
{
register char *s;
register char op = EXACTLY; /* Arbitrary non-END op. */
register char *next;
/*extern char *strchr();*/
s = r->program + 1;
while (op != END) { /* While that wasn't END last time... */
op = OP(s);
printf("%2d%s", s - r->program, regprop(s)); /* Where, what. */
next = regnext(s);
if (next == NULL) /* Next ptr. */
printf("(0)");
else
printf("(%d)", (s - r->program) + (next - s));
s += 3;
if (op == ANYOF || op == ANYBUT || op == EXACTLY) {
/* Literal string, where present. */
while (*s != '\0') {
putchar(*s);
s++;
}
s++;
}
putchar('\n');
}
/* Header fields of interest. */
if (r->regstart != '\0')
printf("start `%c' ", r->regstart);
if (r->reganch)
printf("anchored ");
if (r->regmust != NULL)
printf("must have \"%s\"", r->regmust);
printf("\n");
}
/*
- regprop - printable representation of opcode
*/
static char *
regprop(op)
char *op;
{
register char *p;
static char buf[50];
(void) strcpy(buf, ":");
switch (OP(op)) {
case BOL:
p = "BOL";
break;
case EOL:
p = "EOL";
break;
case ANY:
p = "ANY";
break;
case ANYOF:
p = "ANYOF";
break;
case ANYBUT:
p = "ANYBUT";
break;
case BRANCH:
p = "BRANCH";
break;
case EXACTLY:
p = "EXACTLY";
break;
case NOTHING:
p = "NOTHING";
break;
case BACK:
p = "BACK";
break;
case END:
p = "END";
break;
case MOPEN + 1:
case MOPEN + 2:
case MOPEN + 3:
case MOPEN + 4:
case MOPEN + 5:
case MOPEN + 6:
case MOPEN + 7:
case MOPEN + 8:
case MOPEN + 9:
sprintf(buf + strlen(buf), "MOPEN%d", OP(op) - MOPEN);
p = NULL;
break;
case MCLOSE + 1:
case MCLOSE + 2:
case MCLOSE + 3:
case MCLOSE + 4:
case MCLOSE + 5:
case MCLOSE + 6:
case MCLOSE + 7:
case MCLOSE + 8:
case MCLOSE + 9:
sprintf(buf + strlen(buf), "MCLOSE%d", OP(op) - MCLOSE);
p = NULL;
break;
case BACKREF + 1:
case BACKREF + 2:
case BACKREF + 3:
case BACKREF + 4:
case BACKREF + 5:
case BACKREF + 6:
case BACKREF + 7:
case BACKREF + 8:
case BACKREF + 9:
sprintf(buf + strlen(buf), "BACKREF%d", OP(op) - BACKREF);
p = NULL;
break;
case STAR:
p = "STAR";
break;
case PLUS:
p = "PLUS";
break;
default:
sprintf(buf + strlen(buf), "corrupt %d", OP(op));
p = NULL;
break;
}
if (p != NULL)
(void) strcat(buf, p);
return buf;
}
#endif
/*
* The following is provided for those people who do not have strcspn() in
* their C libraries. They should get off their butts and do something
* about it; at least one public-domain implementation of those (highly
* useful) string routines has been published on Usenet.
*/
#ifdef STRCSPN
/*
* strcspn - find length of initial segment of s1 consisting entirely
* of characters not from s2
*/
static int
strcspn(s1, s2)
const char *s1;
const char *s2;
{
register char *scan1;
register char *scan2;
register int count;
count = 0;
for (scan1 = s1; *scan1 != '\0'; scan1++) {
for (scan2 = s2; *scan2 != '\0';) /* ++ moved down. */
if (*scan1 == *scan2++)
return count;
count++;
}
return count;
}
#endif
/*
* Compare two strings, ignore case if reg_ic set.
* Return 0 if strings match, non-zero otherwise.
*/
static int
cstrncmp(s1, s2, n)
char *s1, *s2;
int n;
{
if (!reg_ic)
return strncmp(s1, s2, (size_t)n);
#ifndef UNIX
return strnicmp(s1, s2, (size_t)n);
#else
# ifdef STRNCASECMP
return strncasecmp(s1, s2, (size_t)n);
# else
while (n && *s1 && *s2)
{
if (mkup(*s1) != mkup(*s2))
return 1;
s1++;
s2++;
n--;
}
if (n)
return 1;
return 0;
# endif /* STRNCASECMP */
#endif /* UNIX */
}
char *
cstrchr(s, c)
char *s;
int c;
{
char *p;
c = mkup(c);
for (p = s; *p; p++)
{
if (mkup(*p) == c)
return p;
#ifdef JP
if (IsKanji(*p))
p++;
#endif
}
return NULL;
}
#ifdef JP
static char *
strjpchr(s, c, k)
char *s;
char c, k;
{
while(*s)
if (IsKanji(*s))
{
if (*s == c && *(s + 1) == k)
return s;
s += 2;
}
else
{
if (*s == c)
return s;
s ++;
}
return NULL;
}
#endif
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