regexp.c

linux系统下的音频通信

		break;
	    case EOL:
		if (*restate->reginput != '\0') {
		    return 0;
		}
		break;
	    case ANY:
		if (*restate->reginput == '\0') {
		    return 0;
		}
		restate->reginput++;
		break;
	    case EXACTLY: {
		register int len;
		register char *opnd;

		opnd = OPERAND(scan);
		/* Inline the first character, for speed. */
		if (*opnd != *restate->reginput) {
		    return 0 ;
		}
		len = strlen(opnd);
		if (len > 1 && strncmp(opnd, restate->reginput, (size_t) len)
			!= 0) {
		    return 0;
		}
		restate->reginput += len;
		break;
	    }
	    case ANYOF:
		if (*restate->reginput == '\0'
			|| strchr(OPERAND(scan), *restate->reginput) == NULL) {
		    return 0;
		}
		restate->reginput++;
		break;
	    case ANYBUT:
		if (*restate->reginput == '\0'
			|| strchr(OPERAND(scan), *restate->reginput) != NULL) {
		    return 0;
		}
		restate->reginput++;
		break;
	    case NOTHING:
		break;
	    case BACK:
		break;
	    case OPEN+1:
	    case OPEN+2:
	    case OPEN+3:
	    case OPEN+4:
	    case OPEN+5:
	    case OPEN+6:
	    case OPEN+7:
	    case OPEN+8:
	    case OPEN+9: {
		register int no;
		register char *save;

	doOpen:
		no = OP(scan) - OPEN;
		save = restate->reginput;

		if (regmatch(next,restate)) {
		    /*
		     * Don't set startp if some later invocation of the
		     * same parentheses already has.
		     */
		    if (restate->regstartp[no] == NULL) {
			restate->regstartp[no] = save;
		    }
		    return 1;
		} else {
		    return 0;
		}
	    }
	    case CLOSE+1:
	    case CLOSE+2:
	    case CLOSE+3:
	    case CLOSE+4:
	    case CLOSE+5:
	    case CLOSE+6:
	    case CLOSE+7:
	    case CLOSE+8:
	    case CLOSE+9: {
		register int no;
		register char *save;

	doClose:
		no = OP(scan) - CLOSE;
		save = restate->reginput;

		if (regmatch(next,restate)) {
				/*
				 * Don't set endp if some later
				 * invocation of the same parentheses
				 * already has.
				 */
		    if (restate->regendp[no] == NULL)
			restate->regendp[no] = save;
		    return 1;
		} else {
		    return 0;
		}
	    }
	    case BRANCH: {
		register char *save;

		if (OP(next) != BRANCH) { /* No choice. */
		    next = OPERAND(scan); /* Avoid recursion. */
		} else {
		    do {
			save = restate->reginput;
			if (regmatch(OPERAND(scan),restate))
			    return(1);
			restate->reginput = save;
			scan = regnext(scan);
		    } while (scan != NULL && OP(scan) == BRANCH);
		    return 0;
		}
		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 = *OPERAND(next);
		min = (OP(scan) == STAR) ? 0 : 1;
		save = restate->reginput;
		no = regrepeat(OPERAND(scan),restate);
		while (no >= min) {
		    /* If it could work, try it. */
		    if (nextch == '\0' || *restate->reginput == nextch)
			if (regmatch(next,restate))
			    return(1);
		    /* Couldn't or didn't -- back up. */
		    no--;
		    restate->reginput = save + no;
		}
		return(0);
	    }
	    case END:
		return(1);	/* Success! */
	    default:
		if (OP(scan) > OPEN && OP(scan) < OPEN+NSUBEXP) {
		    goto doOpen;
		} else if (OP(scan) > CLOSE && OP(scan) < CLOSE+NSUBEXP) {
		    goto doClose;
		}
		TclRegError("memory corruption");
		return 0;
	}

	scan = next;
    }

    /*
     * We get here only if there's trouble -- normally "case END" is
     * the terminating point.
     */
    TclRegError("corrupted pointers");
    return(0);
}

/*
 - regrepeat - repeatedly match something simple, report how many
 */
static int
regrepeat(p, restate)
char *p;
struct regexec_state *restate;
{
	register int count = 0;
	register char *scan;
	register char *opnd;

	scan = restate->reginput;
	opnd = OPERAND(p);
	switch (OP(p)) {
	case ANY:
		count = strlen(scan);
		scan += count;
		break;
	case EXACTLY:
		while (*opnd == *scan) {
			count++;
			scan++;
		}
		break;
	case ANYOF:
		while (*scan != '\0' && strchr(opnd, *scan) != NULL) {
			count++;
			scan++;
		}
		break;
	case ANYBUT:
		while (*scan != '\0' && strchr(opnd, *scan) == NULL) {
			count++;
			scan++;
		}
		break;
	default:		/* Oh dear.  Called inappropriately. */
		TclRegError("internal foulup");
		count = 0;	/* Best compromise. */
		break;
	}
	restate->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 == &regdummy)
		return(NULL);

	offset = NEXT(p);
	if (offset == 0)
		return(NULL);

	if (OP(p) == BACK)
		return(p-offset);
	else
		return(p+offset);
}

#ifdef DEBUG

static char *regprop();

/*
 - 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;


	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 OPEN+1:
	case OPEN+2:
	case OPEN+3:
	case OPEN+4:
	case OPEN+5:
	case OPEN+6:
	case OPEN+7:
	case OPEN+8:
	case OPEN+9:
		sprintf(buf+strlen(buf), "OPEN%d", OP(op)-OPEN);
		p = NULL;
		break;
	case CLOSE+1:
	case CLOSE+2:
	case CLOSE+3:
	case CLOSE+4:
	case CLOSE+5:
	case CLOSE+6:
	case CLOSE+7:
	case CLOSE+8:
	case CLOSE+9:
		sprintf(buf+strlen(buf), "CLOSE%d", OP(op)-CLOSE);
		p = NULL;
		break;
	case STAR:
		p = "STAR";
		break;
	case PLUS:
		p = "PLUS";
		break;
	default:
		if (OP(op) > OPEN && OP(op) < OPEN+NSUBEXP) {
		    sprintf(buf+strlen(buf), "OPEN%d", OP(op)-OPEN);
		    p = NULL;
		    break;
		} else if (OP(op) > CLOSE && OP(op) < CLOSE+NSUBEXP) {
		    sprintf(buf+strlen(buf), "CLOSE%d", OP(op)-CLOSE);
		    p = NULL;
		} else {
		    TclRegError("corrupted opcode");
		}
		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)
char *s1;
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

/*
 *----------------------------------------------------------------------
 *
 * TclRegError --
 *
 *	This procedure is invoked by the regexp code when an error
 *	occurs.  It saves the error message so it can be seen by the
 *	code that called Spencer's code.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The value of "string" is saved in "errMsg".
 *
 *----------------------------------------------------------------------
 */

void
TclRegError(string)
    char *string;			/* Error message. */
{
    errMsg = string;
}

char *
TclGetRegError()
{
    return errMsg;
}