/* $OpenBSD: regexp.c,v 1.1 1996/09/07 21:40:25 downsj Exp $ */
/* vi:set 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.
*
* NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE
*
*
* vim_regcomp and vim_regexec -- vim_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 1.1 1996/09/07 21:40:25 downsj
* Initial revision
*
* 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 vim_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@mbfys.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"
#undef DEBUG
#include <stdio.h>
#include "regexp.h"
#include "option.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 vim_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 vim_regexec() needs it and vim_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 IDENT 14 /* no Match identifier char */
#define WORD 15 /* no Match keyword char */
#define FNAME 16 /* no Match file name char */
#define PRINT 17 /* no Match printable char */
#define SIDENT 18 /* no Match identifier char but no digit */
#define SWORD 19 /* no Match word char but no digit */
#define SFNAME 20 /* no Match file name char but no digit */
#define SPRINT 21 /* no Match printable char but no digit */
#define MOPEN 30 /* no Mark this point in input as start of
* #n. */
/* MOPEN+1 is number 1, etc. */
#define MCLOSE 40 /* no Analogous to MOPEN. */
#define BACKREF 50 /* 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.
* Note: We would like to use "\?" instead of "\=", but a "\?"
* can be part of a pattern to escape the special meaning of '?'
* at the end of the pattern in "?pattern?e".
*
* 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)
/*
* Utility definitions.
*/
#ifndef CHARBITS
#define UCHARAT(p) ((int)*(unsigned char *)(p))
#else
#define UCHARAT(p) ((int)*(p)&CHARBITS)
#endif
#define EMSG_RETURN(m) { emsg(m); rc_did_emsg = TRUE; return NULL; }
static int ismult __ARGS((int));
static char_u *cstrchr __ARGS((char_u *, int));
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 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_u *reg_prev_re;
#endif
#define TILDE
#ifdef TILDE
char_u *reg_prev_sub;
#endif
/*
* Global work variables for vim_regcomp().
*/
static char_u *regparse; /* Input-scan pointer. */
static int regnpar; /* () count. */
static char_u regdummy;
static char_u *regcode; /* Code-emit pointer; ®dummy = don't. */
static long regsize; /* Code size. */
static char_u **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_u META[] = ".[()|=+*<>iIkKfFpP~123456789";
# else
static char_u META[] = ".[()|=+*<>iIkKfFpP~";
# endif
#else
# ifdef BACKREF
static char_u META[] = ".[()|=+*<>iIkKfFpP123456789";
# else
static char_u META[] = ".[()|=+*<>iIkKfFpP";
# endif
#endif
/*
* REGEXP_ABBR contains all characters which act as abbreviations after '\'.
* These are:
* \r - New line (CR).
* \t - Tab (TAB).
* \e - Escape (ESC).
* \b - Backspace (Ctrl('H')).
*/
static char_u REGEXP_ABBR[] = "rteb";
/*
* Forward declarations for vim_regcomp()'s friends.
*/
static void initchr __ARGS((char_u *));
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_u *reg __ARGS((int, int *));
static char_u *regbranch __ARGS((int *));
static char_u *regpiece __ARGS((int *));
static char_u *regatom __ARGS((int *));
static char_u *regnode __ARGS((int));
static char_u *regnext __ARGS((char_u *));
static void regc __ARGS((int));
static void unregc __ARGS((void));
static void reginsert __ARGS((int, char_u *));
static void regtail __ARGS((char_u *, char_u *));
static void regoptail __ARGS((char_u *, char_u *));
#ifndef HAVE_STRCSPN
static size_t strcspn __ARGS((const char_u *, const char_u *));
#endif
/*
* skip past regular expression
* stop at end of 'p' of where 'dirc' is found ('/', '?', etc)
* take care of characters with a backslash in front of it
* skip strings inside [ and ].
*/
char_u *
skip_regexp(p, dirc)
char_u *p;
int dirc;
{
int in_range = FALSE;
for (; p[0] != NUL; ++p)
{
if (p[0] == dirc && !in_range) /* found end of regexp */
break;
if ((p[0] == '[' && p_magic) || (p[0] == '\\' && p[1] == '[' && !p_magic))
{
in_range = TRUE;
if (p[0] == '\\')
++p;
/* "[^]" and "[]" are not the end of a range */
if (p[1] == '^')
++p;
if (p[1] == ']')
++p;
}
else if (p[0] == '\\' && p[1] != NUL)
++p; /* skip next character */
else if (p[0] == ']')
in_range = FALSE;
}
return p;
}
/*
- vim_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 vim_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 *
vim_regcomp(exp)
char_u *exp;
{
register regexp *r;
register char_u *scan;
register char_u *longest;
register int len;
int flags;
/* extern char *malloc();*/
if (exp == NULL)
EMSG_RETURN(e_null);
#ifdef EMPTY_RE /* this is done outside of regexp */
if (*exp == '\0')
{
if (reg_prev_re)
exp = reg_prev_re;
else
EMSG_RETURN(e_noprevre);
}
#endif
/* First pass: determine size, legality. */
initchr((char_u *)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. */
EMSG_RETURN(e_toolong);
/* Allocate space. */
/* r = (regexp *) malloc((unsigned) (sizeof(regexp) + regsize));*/
r = (regexp *) alloc((unsigned) (sizeof(regexp) + regsize));
if (r == NULL)
return NULL;
#ifdef EMPTY_RE /* this is done outside of regexp */
if (exp != reg_prev_re) {
vim_free(reg_prev_re);
if (reg_prev_re = alloc(STRLEN(exp) + 1))
STRCPY(reg_prev_re, exp);
}
#endif
/* Second pass: emit code. */
initchr((char_u *)exp);
regnpar = 1;
regcode = r->program;
regendp = r->endp;
regc(MAGIC);
if (reg(0, &flags) == NULL) {
vim_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.
*/
/*
* When the r.e. starts with BOW, it is faster to look for a regmust
* first. Used a lot for "#" and "*" commands. (Added by mool).
*/
if (flags & SPSTART || OP(scan) == BOW) {
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_u *
reg(paren, flagp)
int paren; /* Parenthesized? */
int *flagp;
{
register char_u *ret;
register char_u *br;
register char_u *ender;
register int parno = 0;
int flags;
*flagp = HASWIDTH; /* Tentatively. */
/* Make an MOPEN node, if parenthesized. */
if (paren) {
if (regnpar >= NSUBEXP)
EMSG_RETURN(e_toombra);
parno = regnpar;
regnpar++;
ret = regnode(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((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(')'))
EMSG_RETURN(e_toombra)
else if (!paren && peekchr() != '\0')
{
if (PeekChr() == Magic(')'))
EMSG_RETURN(e_toomket)
else
EMSG_RETURN(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_u *
regbranch(flagp)
int *flagp;
{
register char_u *ret;
register char_u *chain;
register char_u *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_u *
regpiece(flagp)
int *flagp;
{
register char_u *ret;
register int op;
register char_u *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('='))
EMSG_RETURN((char_u *)"*+ 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()))
EMSG_RETURN((char_u *)"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_u *
regatom(flagp)
int *flagp;
{
register char_u *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('i'):
ret = regnode(IDENT);
*flagp |= HASWIDTH | SIMPLE;
break;
case Magic('k'):
ret = regnode(WORD);
*flagp |= HASWIDTH | SIMPLE;
break;
case Magic('I'):
ret = regnode(SIDENT);
*flagp |= HASWIDTH | SIMPLE;
break;
case Magic('K'):
ret = regnode(SWORD);
*flagp |= HASWIDTH | SIMPLE;
break;
case Magic('f'):
ret = regnode(FNAME);
*flagp |= HASWIDTH | SIMPLE;
break;
case Magic('F'):
ret = regnode(SFNAME);
*flagp |= HASWIDTH | SIMPLE;
break;
case Magic('p'):
ret = regnode(PRINT);
*flagp |= HASWIDTH | SIMPLE;
break;
case Magic('P'):
ret = regnode(SPRINT);
*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(')'):
EMSG_RETURN(e_internal) /* Supposed to be caught earlier. */
/* NOTREACHED */
case Magic('='):
EMSG_RETURN((char_u *)"\\= follows nothing")
/* NOTREACHED */
case Magic('+'):
EMSG_RETURN((char_u *)"\\+ follows nothing")
/* NOTREACHED */
case Magic('*'):
if (reg_magic)
EMSG_RETURN((char_u *)"* follows nothing")
else
EMSG_RETURN((char_u *)"\\* follows nothing")
/* break; Not Reached */
#ifdef TILDE
case Magic('~'): /* previous substitute pattern */
if (reg_prev_sub) {
register char_u *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
EMSG_RETURN(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
EMSG_RETURN((char_u *)"Illegal back reference");
}
break;
#endif
case Magic('['):
{
char_u *p;
/*
* If there is no matching ']', we assume the '[' is a normal
* character. This makes ":help [" work.
*/
p = regparse;
if (*p == '^') /* Complement of range. */
++p;
if (*p == ']' || *p == '-')
++p;
while (*p != '\0' && *p != ']')
{
if (*p == '-')
{
++p;
if (*p != ']' && *p != '\0')
++p;
}
else if (*p == '\\' && p[1] != '\0')
p += 2;
else
++p;
}
if (*p == ']') /* there is a matching ']' */
{
/*
* 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 cclass;
register int cclassend;
cclass = UCHARAT(regparse - 2) + 1;
cclassend = UCHARAT(regparse);
if (cclass > cclassend + 1)
EMSG_RETURN(e_invrange);
for (; cclass <= cclassend; cclass++)
regc(cclass);
regparse++;
}
} else if (*regparse == '\\' && regparse[1]) {
regparse++;
regc(*regparse++);
} else
regc(*regparse++);
}
regc('\0');
if (*regparse != ']')
EMSG_RETURN(e_toomsbra);
skipchr(); /* let's be friends with the lexer again */
*flagp |= HASWIDTH | SIMPLE;
break;
}
}
/* FALLTHROUGH */
default:
{
register int len;
int chr;
ungetchr();
len = 0;
ret = regnode(EXACTLY);
/*
* Always take at least one character, for '[' without matching
* ']'.
*/
while ((chr = peekchr()) != '\0' && (chr < Magic(0) || len == 0))
{
regc(chr);
skipchr();
len++;
}
#ifdef DEBUG
if (len == 0)
EMSG_RETURN((char_u *)"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_u * /* Location. */
regnode(op)
int op;
{
register char_u *ret;
register char_u *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)
*regcode++ = b;
else
regsize++;
}
/*
- unregc - take back (if appropriate) a byte of code
*/
static void
unregc()
{
if (regcode != ®dummy)
regcode--;
else
regsize--;
}
/*
- reginsert - insert an operator in front of already-emitted operand
*
* Means relocating the operand.
*/
static void
reginsert(op, opnd)
int op;
char_u *opnd;
{
register char_u *src;
register char_u *dst;
register char_u *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_u *p;
char_u *val;
{
register char_u *scan;
register char_u *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_u) ((offset >> 8) & 0377);
*(scan + 2) = (char_u) (offset & 0377);
}
/*
- regoptail - regtail on operand of first argument; nop if operandless
*/
static void
regoptail(p, val)
char_u *p;
char_u *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() */
/*
* Note: prevchr is sometimes -1 when we are not at the start,
* eg in /[ ^I]^ the pattern was never found even if it existed, because ^ was
* taken to be magic -- webb
*/
static int at_start; /* True when we are on the first character */
static void
initchr(str)
char_u *str;
{
regparse = str;
curchr = prevchr = nextchr = -1;
at_start = TRUE;
}
static int
peekchr()
{
if (curchr < 0) {
switch (curchr = regparse[0]) {
case '.':
/* case '+':*/
/* case '=':*/
case '[':
case '~':
if (reg_magic)
curchr = Magic(curchr);
break;
case '*':
/* * is not magic as the very first character, eg "?*ptr" */
if (reg_magic && !at_start)
curchr = Magic('*');
break;
case '^':
/* ^ is only magic as the very first character */
if (at_start)
curchr = Magic('^');
break;
case '$':
/* $ is only magic as the very last character and in front of '\|' */
if (regparse[1] == NUL || (regparse[1] == '\\' && regparse[2] == '|'))
curchr = Magic('$');
break;
case '\\':
regparse++;
if (regparse[0] == NUL)
curchr = '\\'; /* trailing '\' */
else if (vim_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;
at_start = FALSE; /* We still want to be able to say "/\*ptr" */
peekchr();
curchr ^= Magic(0);
}
else if (vim_strchr(REGEXP_ABBR, regparse[0]))
{
/*
* Handle abbreviations, like "\t" for TAB -- webb
*/
switch (regparse[0])
{
case 'r': curchr = CR; break;
case 't': curchr = TAB; break;
case 'e': curchr = ESC; break;
case 'b': curchr = Ctrl('H'); break;
}
}
else
{
/*
* Next character can never be (made) magic?
* Then backslashing it won't do anything.
*/
curchr = regparse[0];
}
break;
}
}
return curchr;
}
static void
skipchr()
{
regparse++;
at_start = FALSE;
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.
*/
regparse--;
}
/*
* vim_regexec and friends
*/
/*
* Global work variables for vim_regexec().
*/
static char_u *reginput; /* String-input pointer. */
static char_u *regbol; /* Beginning of input, for ^ check. */
static char_u **regstartp; /* Pointer to startp array. */
/* static char_u **regendp; */ /* Ditto for endp. */
/*
* Forwards.
*/
static int regtry __ARGS((regexp *, char_u *));
static int regmatch __ARGS((char_u *));
static int regrepeat __ARGS((char_u *));
#ifdef DEBUG
int regnarrate = 1;
void regdump __ARGS((regexp *));
static char_u *regprop __ARGS((char_u *));
#endif
/*
* vim_regexec - match a regexp against a string
* Return non-zero if there is a match.
*/
int
vim_regexec(prog, string, at_bol)
register regexp *prog;
register char_u *string;
int at_bol;
{
register char_u *s;
/* Be paranoid... */
if (prog == NULL || string == NULL) {
emsg(e_null);
rc_did_emsg = TRUE;
return 0;
}
/* Check validity of program. */
if (UCHARAT(prog->program) != MAGIC) {
emsg(e_re_corr);
rc_did_emsg = TRUE;
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. */
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;
s++;
}
else
/* We don't -- general case. */
do {
if (regtry(prog, s))
return 1;
} while (*s++ != '\0');
/* Failure. */
return 0;
}
/*
- regtry - try match at specific point
*/
static int /* 0 failure, 1 success */
regtry(prog, string)
regexp *prog;
char_u *string;
{
register int i;
register char_u **sp;
register char_u **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_u *prog;
{
register char_u *scan; /* Current node. */
char_u *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 */
if (reginput != regbol && iswordchar(reginput[-1]))
return 0;
if (!reginput[0] || !iswordchar(reginput[0]))
return 0;
break;
case EOW: /* word\>; reginput points after d */
if (reginput == regbol || !iswordchar(reginput[-1]))
return 0;
if (reginput[0] && iswordchar(reginput[0]))
return 0;
break;
case ANY:
if (*reginput == '\0')
return 0;
reginput++;
break;
case IDENT:
if (!isidchar(*reginput))
return 0;
reginput++;
break;
case WORD:
if (!iswordchar(*reginput))
return 0;
reginput++;
break;
case FNAME:
if (!isfilechar(*reginput))
return 0;
reginput++;
break;
case PRINT:
if (charsize(*reginput) != 1)
return 0;
reginput++;
break;
case SIDENT:
if (isdigit(*reginput) || !isidchar(*reginput))
return 0;
reginput++;
break;
case SWORD:
if (isdigit(*reginput) || !iswordchar(*reginput))
return 0;
reginput++;
break;
case SFNAME:
if (isdigit(*reginput) || !isfilechar(*reginput))
return 0;
reginput++;
break;
case SPRINT:
if (isdigit(*reginput) || charsize(*reginput) != 1)
return 0;
reginput++;
break;
case EXACTLY:{
register int len;
register char_u *opnd;
opnd = OPERAND(scan);
/* Inline the first character, for speed. */
if (*opnd != *reginput && (!reg_ic || TO_UPPER(*opnd) != TO_UPPER(*reginput)))
return 0;
len = STRLEN(opnd);
if (len > 1 && cstrncmp(opnd, reginput, len) != 0)
return 0;
reginput += len;
}
break;
case ANYOF:
if (*reginput == '\0' || cstrchr(OPERAND(scan), *reginput) == NULL)
return 0;
reginput++;
break;
case ANYBUT:
if (*reginput == '\0' || cstrchr(OPERAND(scan), *reginput) != NULL)
return 0;
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_u *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_u *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_u *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 int nextch;
register int no;
register char_u *save;
register int min;
/*
* Lookahead to avoid useless match attempts when we know
* what character comes next.
*/
nextch = '\0';
if (OP(next) == EXACTLY)
{
nextch = *OPERAND(next);
if (reg_ic)
nextch = TO_UPPER(nextch);
}
min = (OP(scan) == STAR) ? 0 : 1;
save = reginput;
no = regrepeat(OPERAND(scan));
while (no >= min)
{
/* If it could work, try it. */
if (nextch == '\0' || (*reginput == nextch ||
(reg_ic && TO_UPPER(*reginput) == nextch)))
if (regmatch(next))
return 1;
/* Couldn't or didn't -- back up. */
no--;
reginput = save + no;
}
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_u *p;
{
register int count = 0;
register char_u *scan;
register char_u *opnd;
scan = reginput;
opnd = OPERAND(p);
switch (OP(p)) {
case ANY:
count = STRLEN(scan);
scan += count;
break;
case IDENT:
for (count = 0; isidchar(*scan); ++count)
++scan;
break;
case WORD:
for (count = 0; iswordchar(*scan); ++count)
++scan;
break;
case FNAME:
for (count = 0; isfilechar(*scan); ++count)
++scan;
break;
case PRINT:
for (count = 0; charsize(*scan) == 1; ++count)
++scan;
break;
case SIDENT:
for (count = 0; !isdigit(*scan) && isidchar(*scan); ++count)
++scan;
break;
case SWORD:
for (count = 0; !isdigit(*scan) && iswordchar(*scan); ++count)
++scan;
break;
case SFNAME:
for (count = 0; !isdigit(*scan) && isfilechar(*scan); ++count)
++scan;
break;
case SPRINT:
for (count = 0; !isdigit(*scan) && charsize(*scan) == 1; ++count)
++scan;
break;
case EXACTLY:
while (*opnd == *scan || (reg_ic && TO_UPPER(*opnd) == TO_UPPER(*scan)))
{
count++;
scan++;
}
break;
case ANYOF:
while (*scan != '\0' && cstrchr(opnd, *scan) != NULL)
{
count++;
scan++;
}
break;
case ANYBUT:
while (*scan != '\0' && cstrchr(opnd, *scan) == NULL) {
count++;
scan++;
}
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_u *
regnext(p)
register char_u *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_u *s;
register int op = EXACTLY; /* Arbitrary non-END op. */
register char_u *next;
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_u *
regprop(op)
char_u *op;
{
register char_u *p;
static char_u buf[50];
(void) strcpy(buf, ":");
switch (OP(op)) {
case BOL:
p = "BOL";
break;
case EOL:
p = "EOL";
break;
case ANY:
p = "ANY";
break;
case IDENT:
p = "IDENT";
break;
case WORD:
p = "WORD";
break;
case FNAME:
p = "FNAME";
break;
case PRINT:
p = "PRINT";
break;
case SIDENT:
p = "SIDENT";
break;
case SWORD:
p = "SWORD";
break;
case SFNAME:
p = "SFNAME";
break;
case SPRINT:
p = "SPRINT";
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.
*/
#ifndef HAVE_STRCSPN
/*
* strcspn - find length of initial segment of s1 consisting entirely
* of characters not from s2
*/
static size_t
strcspn(s1, s2)
const char_u *s1;
const char_u *s2;
{
register char_u *scan1;
register char_u *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.
*/
int
cstrncmp(s1, s2, n)
char_u *s1, *s2;
int n;
{
if (!reg_ic)
return STRNCMP(s1, s2, (size_t)n);
return vim_strnicmp(s1, s2, (size_t)n);
}
/*
* cstrchr: This function is used a lot for simple searches, keep it fast!
*/
static char_u *
cstrchr(s, c)
char_u *s;
register int c;
{
register char_u *p;
if (!reg_ic)
return vim_strchr(s, c);
c = TO_UPPER(c);
for (p = s; *p; p++)
{
if (TO_UPPER(*p) == c)
return p;
}
return NULL;
}
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