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regexp9.c
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regexp9.c
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/*
Copyright information from the original package:
*/
/*
The authors of this software is Rob Pike.
Copyright (c) 2002 by Lucent Technologies.
Permission to use, copy, modify, and distribute this software for any
purpose without fee is hereby granted, provided that this entire notice
is included in all copies of any software which is or includes a copy
or modification of this software and in all copies of the supporting
documentation for such software.
THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
This is a Unix port of the Plan 9 regular expression library.
Please send comments about the packaging
to Russ Cox <[email protected]>.
----
This software is also made available under the Lucent Public License
version 1.02; see http://plan9.bell-labs.com/plan9dist/license.html
*/
/*
This software was packaged for Unix by Russ Cox.
Please send comments to [email protected].
http://swtch.com/plan9port/unix
*/
#include <stdlib.h>
#include <setjmp.h>
#include <unistd.h>
#include "regexp9.h"
#define nil 0
#define exits(x) exit(x && *x ? 1 : 0)
/****************************************************
* Routines from rune.c, runestrchr.c and utfrune.c *
****************************************************/
#include <stdarg.h>
#include <string.h>
enum
{
Bit1 = 7,
Bitx = 6,
Bit2 = 5,
Bit3 = 4,
Bit4 = 3,
T1 = ((1<<(Bit1+1))-1) ^ 0xFF, /* 0000 0000 */
Tx = ((1<<(Bitx+1))-1) ^ 0xFF, /* 1000 0000 */
T2 = ((1<<(Bit2+1))-1) ^ 0xFF, /* 1100 0000 */
T3 = ((1<<(Bit3+1))-1) ^ 0xFF, /* 1110 0000 */
T4 = ((1<<(Bit4+1))-1) ^ 0xFF, /* 1111 0000 */
Rune1 = (1<<(Bit1+0*Bitx))-1, /* 0000 0000 0111 1111 */
Rune2 = (1<<(Bit2+1*Bitx))-1, /* 0000 0111 1111 1111 */
Rune3 = (1<<(Bit3+2*Bitx))-1, /* 1111 1111 1111 1111 */
Maskx = (1<<Bitx)-1, /* 0011 1111 */
Testx = Maskx ^ 0xFF, /* 1100 0000 */
Bad = Runeerror
};
int
chartorune(Rune *rune, const char *str)
{
int c, c1, c2;
long l;
/*
* one character sequence
* 00000-0007F => T1
*/
c = *(uchar*)str;
if(c < Tx) {
*rune = c;
return 1;
}
/*
* two character sequence
* 0080-07FF => T2 Tx
*/
c1 = *(uchar*)(str+1) ^ Tx;
if(c1 & Testx)
goto bad;
if(c < T3) {
if(c < T2)
goto bad;
l = ((c << Bitx) | c1) & Rune2;
if(l <= Rune1)
goto bad;
*rune = l;
return 2;
}
/*
* three character sequence
* 0800-FFFF => T3 Tx Tx
*/
c2 = *(uchar*)(str+2) ^ Tx;
if(c2 & Testx)
goto bad;
if(c < T4) {
l = ((((c << Bitx) | c1) << Bitx) | c2) & Rune3;
if(l <= Rune2)
goto bad;
*rune = l;
return 3;
}
/*
* bad decoding
*/
bad:
*rune = Bad;
return 1;
}
Rune*
runestrchr(const Rune *s, Rune c)
{
Rune c0 = c;
Rune c1;
if(c == 0) {
while(*s++)
;
return (Rune*)s-1;
}
while((c1 = *s++))
if(c1 == c0)
return (Rune*)s-1;
return 0;
}
char*
utfrune(char *s, long c)
{
long c1;
Rune r;
int n;
if(c < Runesync) /* not part of utf sequence */
return strchr(s, c);
for(;;) {
c1 = *(uchar*)s;
if(c1 < Runeself) { /* one byte rune */
if(c1 == 0)
return 0;
if(c1 == c)
return s;
s++;
continue;
}
n = chartorune(&r, s);
if(r == c)
return s;
s += n;
}
}
/************
* regaux.c *
************/
/*
* save a new match in mp
*/
static void
_renewmatch(Resub *mp, int ms, Resublist *sp)
{
int i;
if(mp==0 || ms<=0)
return;
if(mp[0].s.sp==0 || sp->m[0].s.sp<mp[0].s.sp ||
(sp->m[0].s.sp==mp[0].s.sp && sp->m[0].e.ep>mp[0].e.ep)){
for(i=0; i<ms && i<NSUBEXP; i++)
mp[i] = sp->m[i];
for(; i<ms; i++)
mp[i].s.sp = mp[i].e.ep = 0;
}
}
/*
* Note optimization in _renewthread:
* *lp must be pending when _renewthread called; if *l has been looked
* at already, the optimization is a bug.
*/
static Relist*
_renewthread(Relist *lp, /* _relist to add to */
Reinst *ip, /* instruction to add */
int ms,
Resublist *sep) /* pointers to subexpressions */
{
Relist *p;
for(p=lp; p->inst; p++){
if(p->inst == ip){
if(sep->m[0].s.sp < p->se.m[0].s.sp){
if(ms > 1)
p->se = *sep;
else
p->se.m[0] = sep->m[0];
}
return 0;
}
}
p->inst = ip;
if(ms > 1)
p->se = *sep;
else
p->se.m[0] = sep->m[0];
(++p)->inst = 0;
return p;
}
/*
* same as renewthread, but called with
* initial empty start pointer.
*/
static Relist*
_renewemptythread(Relist *lp, /* _relist to add to */
Reinst *ip, /* instruction to add */
int ms,
char *sp) /* pointers to subexpressions */
{
Relist *p;
for(p=lp; p->inst; p++){
if(p->inst == ip){
if(sp < p->se.m[0].s.sp) {
if(ms > 1)
memset(&p->se, 0, sizeof(p->se));
p->se.m[0].s.sp = sp;
}
return 0;
}
}
p->inst = ip;
if(ms > 1)
memset(&p->se, 0, sizeof(p->se));
p->se.m[0].s.sp = sp;
(++p)->inst = 0;
return p;
}
static Relist*
_rrenewemptythread(Relist *lp, /* _relist to add to */
Reinst *ip, /* instruction to add */
int ms,
Rune *rsp) /* pointers to subexpressions */
{
Relist *p;
for(p=lp; p->inst; p++){
if(p->inst == ip){
if(rsp < p->se.m[0].s.rsp) {
if(ms > 1)
memset(&p->se, 0, sizeof(p->se));
p->se.m[0].s.rsp = rsp;
}
return 0;
}
}
p->inst = ip;
if(ms > 1)
memset(&p->se, 0, sizeof(p->se));
p->se.m[0].s.rsp = rsp;
(++p)->inst = 0;
return p;
}
/*************
* regcomp.c *
*************/
#define TRUE 1
#define FALSE 0
/*
* Parser Information
*/
typedef
struct Node
{
Reinst* first;
Reinst* last;
}Node;
#define NSTACK 20
static Node andstack[NSTACK];
static Node *andp;
static int atorstack[NSTACK];
static int* atorp;
static int cursubid; /* id of current subexpression */
static int subidstack[NSTACK]; /* parallel to atorstack */
static int* subidp;
static int lastwasand; /* Last token was operand */
static int nbra;
static char* exprp; /* pointer to next character in source expression */
static int lexdone;
static int nclass;
static Reclass*classp;
static Reinst* freep;
static int errors;
static Rune yyrune; /* last lex'd rune */
static Reclass*yyclassp; /* last lex'd class */
/* predeclared crap */
static void operator(int);
static void pushand(Reinst*, Reinst*);
static void pushator(int);
static void evaluntil(int);
static int bldcclass(void);
static jmp_buf regkaboom;
static void
rcerror(char *s)
{
errors++;
regerror9(s);
longjmp(regkaboom, 1);
}
static Reinst*
newinst(int t)
{
freep->type = t;
freep->u2.left = 0;
freep->u1.right = 0;
return freep++;
}
static void
operand(int t)
{
Reinst *i;
if(lastwasand)
operator(CAT); /* catenate is implicit */
i = newinst(t);
if(t == CCLASS || t == NCCLASS)
i->u1.cp = yyclassp;
if(t == RUNE)
i->u1.r = yyrune;
pushand(i, i);
lastwasand = TRUE;
}
static void
operator(int t)
{
if(t==RBRA && --nbra<0)
rcerror("unmatched right paren");
if(t==LBRA){
if(++cursubid >= NSUBEXP)
rcerror ("too many subexpressions");
nbra++;
if(lastwasand)
operator(CAT);
} else
evaluntil(t);
if(t != RBRA)
pushator(t);
lastwasand = FALSE;
if(t==STAR || t==QUEST || t==PLUS || t==RBRA)
lastwasand = TRUE; /* these look like operands */
}
static void
regerr2(char *s, int c)
{
char buf[100];
char *cp = buf;
while(*s)
*cp++ = *s++;
*cp++ = c;
*cp = '\0';
rcerror(buf);
}
static void
cant(char *s)
{
char buf[100];
strcpy(buf, "can't happen: ");
strcat(buf, s);
rcerror(buf);
}
static void
pushand(Reinst *f, Reinst *l)
{
if(andp >= &andstack[NSTACK])
cant("operand stack overflow");
andp->first = f;
andp->last = l;
andp++;
}
static void
pushator(int t)
{
if(atorp >= &atorstack[NSTACK])
cant("operator stack overflow");
*atorp++ = t;
*subidp++ = cursubid;
}
static Node*
popand(int op)
{
Reinst *inst;
if(andp <= &andstack[0]){
regerr2("missing operand for ", op);
inst = newinst(NOP);
pushand(inst,inst);
}
return --andp;
}
static int
popator(void)
{
if(atorp <= &atorstack[0])
cant("operator stack underflow");
--subidp;
return *--atorp;
}
static void
evaluntil(int pri)
{
Node *op1, *op2;
Reinst *inst1, *inst2;
while(pri==RBRA || atorp[-1]>=pri){
switch(popator()){
default:
rcerror("unknown operator in evaluntil");
break;
case LBRA: /* must have been RBRA */
op1 = popand('(');
inst2 = newinst(RBRA);
inst2->u1.subid = *subidp;
op1->last->u2.next = inst2;
inst1 = newinst(LBRA);
inst1->u1.subid = *subidp;
inst1->u2.next = op1->first;
pushand(inst1, inst2);
return;
case OR:
op2 = popand('|');
op1 = popand('|');
inst2 = newinst(NOP);
op2->last->u2.next = inst2;
op1->last->u2.next = inst2;
inst1 = newinst(OR);
inst1->u1.right = op1->first;
inst1->u2.left = op2->first;
pushand(inst1, inst2);
break;
case CAT:
op2 = popand(0);
op1 = popand(0);
op1->last->u2.next = op2->first;
pushand(op1->first, op2->last);
break;
case STAR:
op2 = popand('*');
inst1 = newinst(OR);
op2->last->u2.next = inst1;
inst1->u1.right = op2->first;
pushand(inst1, inst1);
break;
case PLUS:
op2 = popand('+');
inst1 = newinst(OR);
op2->last->u2.next = inst1;
inst1->u1.right = op2->first;
pushand(op2->first, inst1);
break;
case QUEST:
op2 = popand('?');
inst1 = newinst(OR);
inst2 = newinst(NOP);
inst1->u2.left = inst2;
inst1->u1.right = op2->first;
op2->last->u2.next = inst2;
pushand(inst1, inst2);
break;
}
}
}
static Reprog*
optimize(Reprog *pp)
{
Reinst *inst, *target;
int size;
Reprog *npp;
Reclass *cl;
int diff;
/*
* get rid of NOOP chains
*/
for(inst=pp->firstinst; inst->type!=END; inst++){
target = inst->u2.next;
while(target->type == NOP)
target = target->u2.next;
inst->u2.next = target;
}
/*
* The original allocation is for an area larger than
* necessary. Reallocate to the actual space used
* and then relocate the code.
*/
size = sizeof(Reprog) + (freep - pp->firstinst)*sizeof(Reinst);
npp = realloc(pp, size);
if(npp==0 || npp==pp)
return pp;
diff = (char *)npp - (char *)pp;
freep = (Reinst *)((char *)freep + diff);
for(inst=npp->firstinst; inst<freep; inst++){
switch(inst->type){
case OR:
case STAR:
case PLUS:
case QUEST:
inst->u1.right = (void*)((char*)inst->u1.right + diff);
break;
case CCLASS:
case NCCLASS:
inst->u1.right = (void*)((char*)inst->u1.right + diff);
cl = inst->u1.cp;
cl->end = (void*)((char*)cl->end + diff);
break;
}
inst->u2.left = (void*)((char*)inst->u2.left + diff);
}
npp->startinst = (void*)((char*)npp->startinst + diff);
return npp;
}
#ifdef DEBUG
static void
dumpstack(void){
Node *stk;
int *ip;
print("operators\n");
for(ip=atorstack; ip<atorp; ip++)
print("0%o\n", *ip);
print("operands\n");
for(stk=andstack; stk<andp; stk++)
print("0%o\t0%o\n", stk->first->type, stk->last->type);
}
static void
dump(Reprog *pp)
{
Reinst *l;
Rune *p;
l = pp->firstinst;
do{
print("%d:\t0%o\t%d\t%d", l-pp->firstinst, l->type,
l->u2.left-pp->firstinst, l->u1.right-pp->firstinst);
if(l->type == RUNE)
print("\t%C\n", l->u1.r);
else if(l->type == CCLASS || l->type == NCCLASS){
print("\t[");
if(l->type == NCCLASS)
print("^");
for(p = l->u1.cp->spans; p < l->u1.cp->end; p += 2)
if(p[0] == p[1])
print("%C", p[0]);
else
print("%C-%C", p[0], p[1]);
print("]\n");
} else
print("\n");
}while(l++->type);
}
#endif
static Reclass*
newclass(void)
{
if(nclass >= NCLASS)
regerr2("too many character classes; limit", NCLASS+'0');
return &(classp[nclass++]);
}
static int
nextc(Rune *rp)
{
if(lexdone){
*rp = 0;
return 1;
}
exprp += chartorune(rp, exprp);
if(*rp == '\\'){
exprp += chartorune(rp, exprp);
return 1;
}
if(*rp == 0)
lexdone = 1;
return 0;
}
static int
lex(int literal, int dot_type)
{
int quoted;
quoted = nextc(&yyrune);
if(literal || quoted){
if(yyrune == 0)
return END;
return RUNE;
}
switch(yyrune){
case 0:
return END;
case '*':
return STAR;
case '?':
return QUEST;
case '+':
return PLUS;
case '|':
return OR;
case '.':
return dot_type;
case '(':
return LBRA;
case ')':
return RBRA;
case '^':
return BOL;
case '$':
return EOL;
case '[':
return bldcclass();
}
return RUNE;
}
static int
bldcclass(void)
{
int type;
Rune r[NCCRUNE];
Rune *p, *ep, *np;
Rune rune;
int quoted;
/* we have already seen the '[' */
type = CCLASS;
yyclassp = newclass();
/* look ahead for negation */
/* SPECIAL CASE!!! negated classes don't match \n */
ep = r;
quoted = nextc(&rune);
if(!quoted && rune == '^'){
type = NCCLASS;
quoted = nextc(&rune);
*ep++ = '\n';
*ep++ = '\n';
}
/* parse class into a set of spans */
for(; ep<&r[NCCRUNE];){
if(rune == 0){
rcerror("malformed '[]'");
return 0;
}
if(!quoted && rune == ']')
break;
if(!quoted && rune == '-'){
if(ep == r){
rcerror("malformed '[]'");
return 0;
}
quoted = nextc(&rune);
if((!quoted && rune == ']') || rune == 0){
rcerror("malformed '[]'");
return 0;
}
*(ep-1) = rune;
} else {
*ep++ = rune;
*ep++ = rune;
}
quoted = nextc(&rune);
}
/* sort on span start */
for(p = r; p < ep; p += 2){
for(np = p; np < ep; np += 2)
if(*np < *p){
rune = np[0];
np[0] = p[0];
p[0] = rune;
rune = np[1];
np[1] = p[1];
p[1] = rune;
}
}
/* merge spans */
np = yyclassp->spans;
p = r;
if(r == ep)
yyclassp->end = np;
else {
np[0] = *p++;
np[1] = *p++;
for(; p < ep; p += 2)
if(p[0] <= np[1]){
if(p[1] > np[1])
np[1] = p[1];
} else {
np += 2;
np[0] = p[0];
np[1] = p[1];
}
yyclassp->end = np+2;
}
return type;
}
static Reprog*
regcomp1(char *s, int literal, int dot_type)
{
int token;
Reprog *volatile pp;
/* get memory for the program */
pp = malloc(sizeof(Reprog) + 6*sizeof(Reinst)*strlen(s));
if(pp == 0){
regerror9("out of memory");
return 0;
}
freep = pp->firstinst;
classp = pp->class;
errors = 0;
if(setjmp(regkaboom))
goto out;
/* go compile the sucker */
lexdone = 0;
exprp = s;
nclass = 0;
nbra = 0;
atorp = atorstack;
andp = andstack;
subidp = subidstack;
lastwasand = FALSE;
cursubid = 0;
/* Start with a low priority operator to prime parser */
pushator(START-1);
while((token = lex(literal, dot_type)) != END){
if((token&0300) == OPERATOR)
operator(token);
else
operand(token);
}
/* Close with a low priority operator */
evaluntil(START);
/* Force END */
operand(END);
evaluntil(START);
#ifdef DEBUG
dumpstack();
#endif
if(nbra)
rcerror("unmatched left paren");
--andp; /* points to first and only operand */
pp->startinst = andp->first;
#ifdef DEBUG
dump(pp);
#endif
pp = optimize(pp);
#ifdef DEBUG
print("start: %d\n", andp->first-pp->firstinst);
dump(pp);
#endif
out:
if(errors){
free(pp);
pp = 0;
}
return pp;
}
extern Reprog*
regcomp9(char *s)
{
return regcomp1(s, 0, ANY);
}
extern Reprog*
regcomplit9(char *s)
{
return regcomp1(s, 1, ANY);
}
extern Reprog*
regcompnl9(char *s)
{
return regcomp1(s, 0, ANYNL);
}
/*************
* regexec.c *
*************/
/*
* return 0 if no match
* >0 if a match
* <0 if we ran out of _relist space
*/
static int
regexec1(const Reprog *progp, /* program to run */
char *bol, /* string to run machine on */
Resub *mp, /* subexpression elements */
int ms, /* number of elements at mp */
Reljunk *j
)
{
int flag=0;
Reinst *inst;
Relist *tlp;
char *s;
int i, checkstart;
Rune r, *rp, *ep;
int n;
Relist* tl; /* This list, next list */
Relist* nl;
Relist* tle; /* ends of this and next list */
Relist* nle;
int match;
char *p;
match = 0;
checkstart = j->starttype;
if(mp)
for(i=0; i<ms; i++) {
mp[i].s.sp = 0;
mp[i].e.ep = 0;
}
j->relist[0][0].inst = 0;
j->relist[1][0].inst = 0;
/* Execute machine once for each character, including terminal NUL */
s = j->starts;
do{
/* fast check for first char */
if(checkstart) {
switch(j->starttype) {
case RUNE:
p = utfrune(s, j->startchar);
if(p == 0 || s == j->eol)
return match;
s = p;
break;
case BOL:
if(s == bol)
break;
p = utfrune(s, '\n');
if(p == 0 || s == j->eol)
return match;
s = p+1;
break;
}
}
r = *(uchar*)s;
if(r < Runeself)
n = 1;
else
n = chartorune(&r, s);
/* switch run lists */
tl = j->relist[flag];
tle = j->reliste[flag];
nl = j->relist[flag^=1];
nle = j->reliste[flag];
nl->inst = 0;
/* Add first instruction to current list */
if(match == 0)
_renewemptythread(tl, progp->startinst, ms, s);
/* Execute machine until current list is empty */
for(tlp=tl; tlp->inst; tlp++){ /* assignment = */
for(inst = tlp->inst; ; inst = inst->u2.next){
switch(inst->type){
case RUNE: /* regular character */
if(inst->u1.r == r){
if(_renewthread(nl, inst->u2.next, ms, &tlp->se)==nle)
return -1;
}
break;
case LBRA:
tlp->se.m[inst->u1.subid].s.sp = s;
continue;
case RBRA:
tlp->se.m[inst->u1.subid].e.ep = s;
continue;
case ANY:
if(r != '\n')
if(_renewthread(nl, inst->u2.next, ms, &tlp->se)==nle)
return -1;
break;
case ANYNL:
if(_renewthread(nl, inst->u2.next, ms, &tlp->se)==nle)
return -1;
break;
case BOL:
if(s == bol || *(s-1) == '\n')
continue;
break;
case EOL:
if(s == j->eol || r == 0 || r == '\n')
continue;
break;
case CCLASS:
ep = inst->u1.cp->end;
for(rp = inst->u1.cp->spans; rp < ep; rp += 2)
if(r >= rp[0] && r <= rp[1]){
if(_renewthread(nl, inst->u2.next, ms, &tlp->se)==nle)
return -1;
break;
}
break;
case NCCLASS:
ep = inst->u1.cp->end;
for(rp = inst->u1.cp->spans; rp < ep; rp += 2)
if(r >= rp[0] && r <= rp[1])
break;
if(rp == ep)
if(_renewthread(nl, inst->u2.next, ms, &tlp->se)==nle)
return -1;
break;
case OR:
/* evaluate right choice later */
if(_renewthread(tlp, inst->u1.right, ms, &tlp->se) == tle)
return -1;
/* efficiency: advance and re-evaluate */
continue;
case END: /* Match! */
match = 1;
tlp->se.m[0].e.ep = s;
if(mp != 0)
_renewmatch(mp, ms, &tlp->se);
break;
}
break;
}
}
if(s == j->eol)
break;
checkstart = j->starttype && nl->inst==0;
s += n;
}while(r);
return match;
}
static int
regexec2(const Reprog *progp, /* program to run */
char *bol, /* string to run machine on */