ref: 548f7f971f5938c1b54481e0542d5b19e0fe37de
dir: /sys/src/ape/cmd/expr/regexp.h/
#define CBRA 2
#define CCHR 4
#define CDOT 8
#define CCL 12
#define CDOL 20
#define CEOF 22
#define CKET 24
#define CBACK 36
#define STAR 01
#define RNGE 03
#define NBRA 9
#define PLACE(c) ep[c >> 3] |= bittab[c & 07]
#define ISTHERE(c) (ep[c >> 3] & bittab[c & 07])
char *braslist[NBRA];
char *braelist[NBRA];
int nbra, ebra;
char *loc1, *loc2, *locs;
int sed;
int circf;
int low;
int size;
char bittab[] = {
1,
2,
4,
8,
16,
32,
64,
128
};
char *
compile(char *instring, char *ep, char *endbuf, int seof)
{
INIT /* Dependent declarations and initializations */
register c;
register eof = seof;
char *lastep = instring;
int cclcnt;
char bracket[NBRA], *bracketp;
int closed;
char neg;
int lc;
int i, cflg;
lastep = 0;
if((c = GETC()) == eof) {
if(*ep == 0 && !sed)
ERROR(41);
RETURN(ep);
}
bracketp = bracket;
circf = closed = nbra = ebra = 0;
if (c == '^')
circf++;
else
UNGETC(c);
for (;;) {
if (ep >= endbuf)
ERROR(50);
if((c = GETC()) != '*' && ((c != '\\') || (PEEKC() != '{')))
lastep = ep;
if (c == eof) {
*ep++ = CEOF;
RETURN(ep);
}
switch (c) {
case '.':
*ep++ = CDOT;
continue;
case '\n':
ERROR(36);
case '*':
if (lastep==0 || *lastep==CBRA || *lastep==CKET)
goto defchar;
*lastep |= STAR;
continue;
case '$':
if(PEEKC() != eof)
goto defchar;
*ep++ = CDOL;
continue;
case '[':
if(&ep[17] >= endbuf)
ERROR(50);
*ep++ = CCL;
lc = 0;
for(i = 0; i < 16; i++)
ep[i] = 0;
neg = 0;
if((c = GETC()) == '^') {
neg = 1;
c = GETC();
}
do {
if(c == '\0' || c == '\n')
ERROR(49);
if(c == '-' && lc != 0) {
if ((c = GETC()) == ']') {
PLACE('-');
break;
}
while(lc < c) {
PLACE(lc);
lc++;
}
}
lc = c;
PLACE(c);
} while((c = GETC()) != ']');
if(neg) {
for(cclcnt = 0; cclcnt < 16; cclcnt++)
ep[cclcnt] ^= -1;
ep[0] &= 0376;
}
ep += 16;
continue;
case '\\':
switch(c = GETC()) {
case '(':
if(nbra >= NBRA)
ERROR(43);
*bracketp++ = nbra;
*ep++ = CBRA;
*ep++ = nbra++;
continue;
case ')':
if(bracketp <= bracket || ++ebra != nbra)
ERROR(42);
*ep++ = CKET;
*ep++ = *--bracketp;
closed++;
continue;
case '{':
if(lastep == (char *) (0))
goto defchar;
*lastep |= RNGE;
cflg = 0;
nlim:
c = GETC();
i = 0;
do {
if ('0' <= c && c <= '9')
i = 10 * i + c - '0';
else
ERROR(16);
} while(((c = GETC()) != '\\') && (c != ','));
if (i > 255)
ERROR(11);
*ep++ = i;
if (c == ',') {
if(cflg++)
ERROR(44);
if((c = GETC()) == '\\')
*ep++ = 255;
else {
UNGETC(c);
goto nlim; /* get 2'nd number */
}
}
if(GETC() != '}')
ERROR(45);
if(!cflg) /* one number */
*ep++ = i;
else if((ep[-1] & 0377) < (ep[-2] & 0377))
ERROR(46);
continue;
case '\n':
ERROR(36);
case 'n':
c = '\n';
goto defchar;
default:
if(c >= '1' && c <= '9') {
if((c -= '1') >= closed)
ERROR(25);
*ep++ = CBACK;
*ep++ = c;
continue;
}
}
/* Drop through to default to use \ to turn off special chars */
defchar:
default:
lastep = ep;
*ep++ = CCHR;
*ep++ = c;
}
}
}
step(char *p1, char *p2)
{
register c;
if (circf) {
loc1 = p1;
return(advance(p1, p2));
}
/* fast check for first character */
if (*p2==CCHR) {
c = p2[1];
do {
if (*p1 != c)
continue;
if (advance(p1, p2)) {
loc1 = p1;
return(1);
}
} while (*p1++);
return(0);
}
/* regular algorithm */
do {
if (advance(p1, p2)) {
loc1 = p1;
return(1);
}
} while (*p1++);
return(0);
}
advance(char *lp, char *ep)
{
register char *curlp;
char c;
char *bbeg;
int ct;
for (;;) switch (*ep++) {
case CCHR:
if (*ep++ == *lp++)
continue;
return(0);
case CDOT:
if (*lp++)
continue;
return(0);
case CDOL:
if (*lp==0)
continue;
return(0);
case CEOF:
loc2 = lp;
return(1);
case CCL:
c = *lp++ & 0177;
if(ISTHERE(c)) {
ep += 16;
continue;
}
return(0);
case CBRA:
braslist[*ep++] = lp;
continue;
case CKET:
braelist[*ep++] = lp;
continue;
case CCHR|RNGE:
c = *ep++;
getrnge(ep);
while(low--)
if(*lp++ != c)
return(0);
curlp = lp;
while(size--)
if(*lp++ != c)
break;
if(size < 0)
lp++;
ep += 2;
goto star;
case CDOT|RNGE:
getrnge(ep);
while(low--)
if(*lp++ == '\0')
return(0);
curlp = lp;
while(size--)
if(*lp++ == '\0')
break;
if(size < 0)
lp++;
ep += 2;
goto star;
case CCL|RNGE:
getrnge(ep + 16);
while(low--) {
c = *lp++ & 0177;
if(!ISTHERE(c))
return(0);
}
curlp = lp;
while(size--) {
c = *lp++ & 0177;
if(!ISTHERE(c))
break;
}
if(size < 0)
lp++;
ep += 18; /* 16 + 2 */
goto star;
case CBACK:
bbeg = braslist[*ep];
ct = braelist[*ep++] - bbeg;
if(ecmp(bbeg, lp, ct)) {
lp += ct;
continue;
}
return(0);
case CBACK|STAR:
bbeg = braslist[*ep];
ct = braelist[*ep++] - bbeg;
curlp = lp;
while(ecmp(bbeg, lp, ct))
lp += ct;
while(lp >= curlp) {
if(advance(lp, ep)) return(1);
lp -= ct;
}
return(0);
case CDOT|STAR:
curlp = lp;
while (*lp++);
goto star;
case CCHR|STAR:
curlp = lp;
while (*lp++ == *ep);
ep++;
goto star;
case CCL|STAR:
curlp = lp;
do {
c = *lp++ & 0177;
} while(ISTHERE(c));
ep += 16;
goto star;
star:
do {
if(--lp == locs)
break;
if (advance(lp, ep))
return(1);
} while (lp > curlp);
return(0);
}
}
getrnge(char *str)
{
low = *str++ & 0377;
size = *str == 255 ? 20000 : (*str &0377) - low;
}
ecmp(char *a, char *b, int count)
{
while(count--)
if(*a++ != *b++) return(0);
return(1);
}