regcomp.c

早期freebsd实现

					regset(bits,def,class);
				lastclass = 1234;
				continue;
			case 'W':
				for (class = 0; class < 256; class++)
				    if (!isALNUM(class))
					regset(bits,def,class);
				lastclass = 1234;
				continue;
			case 's':
				for (class = 0; class < 256; class++)
				    if (isSPACE(class))
					regset(bits,def,class);
				lastclass = 1234;
				continue;
			case 'S':
				for (class = 0; class < 256; class++)
				    if (!isSPACE(class))
					regset(bits,def,class);
				lastclass = 1234;
				continue;
			case 'd':
				for (class = '0'; class <= '9'; class++)
					regset(bits,def,class);
				lastclass = 1234;
				continue;
			case 'D':
				for (class = 0; class < '0'; class++)
					regset(bits,def,class);
				for (class = '9' + 1; class < 256; class++)
					regset(bits,def,class);
				lastclass = 1234;
				continue;
			case 'n':
				class = '\n';
				break;
			case 'r':
				class = '\r';
				break;
			case 't':
				class = '\t';
				break;
			case 'f':
				class = '\f';
				break;
			case 'b':
				class = '\b';
				break;
			case 'e':
				class = '\033';
				break;
			case 'a':
				class = '\007';
				break;
			case 'x':
				class = scanhex(regparse, 2, &numlen);
				regparse += numlen;
				break;
			case 'c':
				class = *regparse++;
				if (isLOWER(class))
				    class = toupper(class);
				class ^= 64;
				break;
			case '0': case '1': case '2': case '3': case '4':
			case '5': case '6': case '7': case '8': case '9':
				class = scanoct(--regparse, 3, &numlen);
				regparse += numlen;
				break;
			}
		}
		if (range) {
			if (lastclass > class)
				FAIL("invalid [] range in regexp");
			range = 0;
		}
		else {
			lastclass = class;
			if (*regparse == '-' && regparse+1 < regxend &&
			    regparse[1] != ']') {
				regparse++;
				range = 1;
				continue;	/* do it next time */
			}
		}
		for ( ; lastclass <= class; lastclass++) {
			regset(bits,def,lastclass);
			if (regfold && isUPPER(lastclass))
				regset(bits,def,tolower(lastclass));
		}
		lastclass = class;
	}
	if (*regparse != ']')
		FAIL("unmatched [] in regexp");
	regparse++;
	return ret;
}

/*
 - regnode - emit a node
 */
static char *			/* Location. */
regnode(op)
char op;
{
	register char *ret;
	register char *ptr;

	ret = regcode;
	if (ret == &regdummy) {
#ifdef REGALIGN
		if (!(regsize & 1))
			regsize++;
#endif
		regsize += 3;
		return(ret);
	}

#ifdef REGALIGN
#ifndef lint
	if (!((long)ret & 1))
	    *ret++ = 127;
#endif
#endif
	ptr = ret;
	*ptr++ = op;
	*ptr++ = '\0';		/* Null "next" pointer. */
	*ptr++ = '\0';
	regcode = ptr;

	return(ret);
}

/*
 - reganode - emit a node with an argument
 */
static char *			/* Location. */
reganode(op, arg)
char op;
unsigned short arg;
{
	register char *ret;
	register char *ptr;

	ret = regcode;
	if (ret == &regdummy) {
#ifdef REGALIGN
		if (!(regsize & 1))
			regsize++;
#endif
		regsize += 5;
		return(ret);
	}

#ifdef REGALIGN
#ifndef lint
	if (!((long)ret & 1))
	    *ret++ = 127;
#endif
#endif
	ptr = ret;
	*ptr++ = op;
	*ptr++ = '\0';		/* Null "next" pointer. */
	*ptr++ = '\0';
#ifdef REGALIGN
	*(unsigned short *)(ret+3) = arg;
#else
	ret[3] = arg >> 8; ret[4] = arg & 0377;
#endif
	ptr += 2;
	regcode = ptr;

	return(ret);
}

/*
 - regc - emit (if appropriate) a byte of code
 */
static void
regc(b)
char b;
{
	if (regcode != &regdummy)
		*regcode++ = b;
	else
		regsize++;
}

/*
 - reginsert - insert an operator in front of already-emitted operand
 *
 * Means relocating the operand.
 */
static void
reginsert(op, opnd)
char op;
char *opnd;
{
	register char *src;
	register char *dst;
	register char *place;
	register offset = (op == CURLY ? 4 : 0);

	if (regcode == &regdummy) {
#ifdef REGALIGN
		regsize += 4 + offset;
#else
		regsize += 3 + offset;
#endif
		return;
	}

	src = regcode;
#ifdef REGALIGN
	regcode += 4 + offset;
#else
	regcode += 3 + offset;
#endif
	dst = regcode;
	while (src > opnd)
		*--dst = *--src;

	place = opnd;		/* Op node, where operand used to be. */
	*place++ = op;
	*place++ = '\0';
	*place++ = '\0';
	while (offset-- > 0)
	    *place++ = '\0';
#ifdef REGALIGN
	*place++ = '\177';
#endif
}

/*
 - 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 == &regdummy)
		return;

	/* Find last node. */
	scan = p;
	for (;;) {
		temp = regnext(scan);
		if (temp == NULL)
			break;
		scan = temp;
	}

#ifdef REGALIGN
	offset = val - scan;
#ifndef lint
	*(short*)(scan+1) = offset;
#else
	offset = offset;
#endif
#else
	if (OP(scan) == BACK)
		offset = scan - val;
	else
		offset = val - scan;
	*(scan+1) = (offset>>8)&0377;
	*(scan+2) = offset&0377;
#endif
}

/*
 - 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 == &regdummy || OP(p) != BRANCH)
		return;
	regtail(NEXTOPER(p), val);
}

/*
 - regcurly - a little FSA that accepts {\d+,?\d*}
 */
STATIC int
regcurly(s)
register char *s;
{
    if (*s++ != '{')
	return FALSE;
    if (!isDIGIT(*s))
	return FALSE;
    while (isDIGIT(*s))
	s++;
    if (*s == ',')
	s++;
    while (isDIGIT(*s))
	s++;
    if (*s != '}')
	return FALSE;
    return TRUE;
}

#ifdef DEBUGGING

/*
 - regdump - dump a regexp onto stderr in vaguely comprehensible form
 */
void
regdump(r)
regexp *r;
{
	register char *s;
	register char op = EXACTLY;	/* Arbitrary non-END op. */
	register char *next;


	s = r->program + 1;
	while (op != END) {	/* While that wasn't END last time... */
#ifdef REGALIGN
		if (!((long)s & 1))
			s++;
#endif
		op = OP(s);
		fprintf(stderr,"%2d%s", s-r->program, regprop(s));	/* Where, what. */
		next = regnext(s);
		s += regarglen[op];
		if (next == NULL)		/* Next ptr. */
			fprintf(stderr,"(0)");
		else 
			fprintf(stderr,"(%d)", (s-r->program)+(next-s));
		s += 3;
		if (op == ANYOF) {
			s += 32;
		}
		if (op == EXACTLY) {
			/* Literal string, where present. */
			s++;
			while (*s != '\0') {
				(void)putchar(*s);
				s++;
			}
			s++;
		}
		(void)putchar('\n');
	}

	/* Header fields of interest. */
	if (r->regstart)
		fprintf(stderr,"start `%s' ", r->regstart->str_ptr);
	if (r->regstclass)
		fprintf(stderr,"stclass `%s' ", regprop(r->regstclass));
	if (r->reganch & ROPT_ANCH)
		fprintf(stderr,"anchored ");
	if (r->reganch & ROPT_SKIP)
		fprintf(stderr,"plus ");
	if (r->reganch & ROPT_IMPLICIT)
		fprintf(stderr,"implicit ");
	if (r->regmust != NULL)
		fprintf(stderr,"must have \"%s\" back %d ", r->regmust->str_ptr,
		  r->regback);
	fprintf(stderr, "minlen %d ", r->minlen);
	fprintf(stderr,"\n");
}

/*
 - regprop - printable representation of opcode
 */
char *
regprop(op)
char *op;
{
	register char *p;

	(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 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 ALNUM:
		p = "ALNUM";
		break;
	case NALNUM:
		p = "NALNUM";
		break;
	case BOUND:
		p = "BOUND";
		break;
	case NBOUND:
		p = "NBOUND";
		break;
	case SPACE:
		p = "SPACE";
		break;
	case NSPACE:
		p = "NSPACE";
		break;
	case DIGIT:
		p = "DIGIT";
		break;
	case NDIGIT:
		p = "NDIGIT";
		break;
	case CURLY:
		(void)sprintf(buf+strlen(buf), "CURLY {%d,%d}",
		    ARG1(op),ARG2(op));
		p = NULL;
		break;
	case REF:
		(void)sprintf(buf+strlen(buf), "REF%d", ARG1(op));
		p = NULL;
		break;
	case OPEN:
		(void)sprintf(buf+strlen(buf), "OPEN%d", ARG1(op));
		p = NULL;
		break;
	case CLOSE:
		(void)sprintf(buf+strlen(buf), "CLOSE%d", ARG1(op));
		p = NULL;
		break;
	case STAR:
		p = "STAR";
		break;
	case PLUS:
		p = "PLUS";
		break;
	default:
		FAIL("corrupted regexp opcode");
	}
	if (p != NULL)
		(void) strcat(buf, p);
	return(buf);
}
#endif /* DEBUGGING */

void
regfree(r)
struct regexp *r;
{
	if (r->precomp) {
		Safefree(r->precomp);
		r->precomp = Nullch;
	}
	if (r->subbase) {
		Safefree(r->subbase);
		r->subbase = Nullch;
	}
	if (r->regmust) {
		str_free(r->regmust);
		r->regmust = Nullstr;
	}
	if (r->regstart) {
		str_free(r->regstart);
		r->regstart = Nullstr;
	}
	Safefree(r->startp);
	Safefree(r->endp);
	Safefree(r);
}