list.c

早期freebsd实现

			break;
		if (argn >= argc - 1) {
			printf(
			"Too many elements in the list; excess discarded.\n");
			break;
		}
		cp2 = linebuf;
		quotec = '\0';
		while ((c = *cp) != '\0') {
			cp++;
			if (quotec != '\0') {
				if (c == quotec)
					quotec = '\0';
				else if (c == '\\')
					switch (c = *cp++) {
					case '\0':
						*cp2++ = '\\';
						cp--;
						break;
					case '0': case '1': case '2': case '3':
					case '4': case '5': case '6': case '7':
						c -= '0';
						if (*cp >= '0' && *cp <= '7')
							c = c * 8 + *cp++ - '0';
						if (*cp >= '0' && *cp <= '7')
							c = c * 8 + *cp++ - '0';
						*cp2++ = c;
						break;
					case 'b':
						*cp2++ = '\b';
						break;
					case 'f':
						*cp2++ = '\f';
						break;
					case 'n':
						*cp2++ = '\n';
						break;
					case 'r':
						*cp2++ = '\r';
						break;
					case 't':
						*cp2++ = '\t';
						break;
					case 'v':
						*cp2++ = '\v';
						break;
					default:
						*cp2++ = c;
					}
				else if (c == '^') {
					c = *cp++;
					if (c == '?')
						*cp2++ = '\177';
					/* null doesn't show up anyway */
					else if (c >= 'A' && c <= '_' ||
						 c >= 'a' && c <= 'z')
						*cp2++ = c & 037;
					else {
						*cp2++ = '^';
						cp--;
					}
				} else
					*cp2++ = c;
			} else if (c == '"' || c == '\'')
				quotec = c;
			else if (c == ' ' || c == '\t')
				break;
			else
				*cp2++ = c;
		}
		*cp2 = '\0';
		argv[argn++] = savestr(linebuf);
	}
	argv[argn] = NOSTR;
	return argn;
}

/*
 * scan out a single lexical item and return its token number,
 * updating the string pointer passed **p.  Also, store the value
 * of the number or string scanned in lexnumber or lexstring as
 * appropriate.  In any event, store the scanned `thing' in lexstring.
 */

struct lex {
	char	l_char;
	char	l_token;
} singles[] = {
	'$',	TDOLLAR,
	'.',	TDOT,
	'^',	TUP,
	'*',	TSTAR,
	'-',	TDASH,
	'+',	TPLUS,
	'(',	TOPEN,
	')',	TCLOSE,
	0,	0
};

int
scan(sp)
	char **sp;
{
	register char *cp, *cp2;
	register int c;
	register struct lex *lp;
	int quotec;

	if (regretp >= 0) {
		strcpy(lexstring, string_stack[regretp]);
		lexnumber = numberstack[regretp];
		return(regretstack[regretp--]);
	}
	cp = *sp;
	cp2 = lexstring;
	c = *cp++;

	/*
	 * strip away leading white space.
	 */

	while (c == ' ' || c == '\t')
		c = *cp++;

	/*
	 * If no characters remain, we are at end of line,
	 * so report that.
	 */

	if (c == '\0') {
		*sp = --cp;
		return(TEOL);
	}

	/*
	 * If the leading character is a digit, scan
	 * the number and convert it on the fly.
	 * Return TNUMBER when done.
	 */

	if (isdigit(c)) {
		lexnumber = 0;
		while (isdigit(c)) {
			lexnumber = lexnumber*10 + c - '0';
			*cp2++ = c;
			c = *cp++;
		}
		*cp2 = '\0';
		*sp = --cp;
		return(TNUMBER);
	}

	/*
	 * Check for single character tokens; return such
	 * if found.
	 */

	for (lp = &singles[0]; lp->l_char != 0; lp++)
		if (c == lp->l_char) {
			lexstring[0] = c;
			lexstring[1] = '\0';
			*sp = cp;
			return(lp->l_token);
		}

	/*
	 * We've got a string!  Copy all the characters
	 * of the string into lexstring, until we see
	 * a null, space, or tab.
	 * If the lead character is a " or ', save it
	 * and scan until you get another.
	 */

	quotec = 0;
	if (c == '\'' || c == '"') {
		quotec = c;
		c = *cp++;
	}
	while (c != '\0') {
		if (c == quotec) {
			cp++;
			break;
		}
		if (quotec == 0 && (c == ' ' || c == '\t'))
			break;
		if (cp2 - lexstring < STRINGLEN-1)
			*cp2++ = c;
		c = *cp++;
	}
	if (quotec && c == 0) {
		fprintf(stderr, "Missing %c\n", quotec);
		return TERROR;
	}
	*sp = --cp;
	*cp2 = '\0';
	return(TSTRING);
}

/*
 * Unscan the named token by pushing it onto the regret stack.
 */
void
regret(token)
	int token;
{
	if (++regretp >= REGDEP)
		panic("Too many regrets");
	regretstack[regretp] = token;
	lexstring[STRINGLEN-1] = '\0';
	string_stack[regretp] = savestr(lexstring);
	numberstack[regretp] = lexnumber;
}

/*
 * Reset all the scanner global variables.
 */
void
scaninit()
{
	regretp = -1;
}

/*
 * Find the first message whose flags & m == f  and return
 * its message number.
 */
int
first(f, m)
	int f, m;
{
	register struct message *mp;

	if (msgCount == 0)
		return 0;
	f &= MDELETED;
	m &= MDELETED;
	for (mp = dot; mp < &message[msgCount]; mp++)
		if ((mp->m_flag & m) == f)
			return mp - message + 1;
	for (mp = dot-1; mp >= &message[0]; mp--)
		if ((mp->m_flag & m) == f)
			return mp - message + 1;
	return 0;
}

/*
 * See if the passed name sent the passed message number.  Return true
 * if so.
 */
int
matchsender(str, mesg)
	char *str;
	int mesg;
{
	register char *cp, *cp2, *backup;

	if (!*str)	/* null string matches nothing instead of everything */
		return 0;
	backup = cp2 = nameof(&message[mesg - 1], 0);
	cp = str;
	while (*cp2) {
		if (*cp == 0)
			return(1);
		if (raise(*cp++) != raise(*cp2++)) {
			cp2 = ++backup;
			cp = str;
		}
	}
	return(*cp == 0);
}

/*
 * See if the given string matches inside the subject field of the
 * given message.  For the purpose of the scan, we ignore case differences.
 * If it does, return true.  The string search argument is assumed to
 * have the form "/search-string."  If it is of the form "/," we use the
 * previous search string.
 */

char lastscan[128];
int
matchsubj(str, mesg)
	char *str;
	int mesg;
{
	register struct message *mp;
	register char *cp, *cp2, *backup;

	str++;
	if (strlen(str) == 0)
		str = lastscan;
	else
		strcpy(lastscan, str);
	mp = &message[mesg-1];
	
	/*
	 * Now look, ignoring case, for the word in the string.
	 */

	if (value("searchheaders") && (cp = index(str, ':'))) {
		*cp++ = '\0';
		cp2 = hfield(str, mp);
		cp[-1] = ':';
		str = cp;
	} else {
		cp = str;
		cp2 = hfield("subject", mp);
	}
	if (cp2 == NOSTR)
		return(0);
	backup = cp2;
	while (*cp2) {
		if (*cp == 0)
			return(1);
		if (raise(*cp++) != raise(*cp2++)) {
			cp2 = ++backup;
			cp = str;
		}
	}
	return(*cp == 0);
}

/*
 * Mark the named message by setting its mark bit.
 */
void
mark(mesg)
	int mesg;
{
	register int i;

	i = mesg;
	if (i < 1 || i > msgCount)
		panic("Bad message number to mark");
	message[i-1].m_flag |= MMARK;
}

/*
 * Unmark the named message.
 */
void
unmark(mesg)
	int mesg;
{
	register int i;

	i = mesg;
	if (i < 1 || i > msgCount)
		panic("Bad message number to unmark");
	message[i-1].m_flag &= ~MMARK;
}

/*
 * Return the message number corresponding to the passed meta character.
 */
int
metamess(meta, f)
	int meta, f;
{
	register int c, m;
	register struct message *mp;

	c = meta;
	switch (c) {
	case '^':
		/*
		 * First 'good' message left.
		 */
		for (mp = &message[0]; mp < &message[msgCount]; mp++)
			if ((mp->m_flag & MDELETED) == f)
				return(mp - &message[0] + 1);
		printf("No applicable messages\n");
		return(-1);

	case '$':
		/*
		 * Last 'good message left.
		 */
		for (mp = &message[msgCount-1]; mp >= &message[0]; mp--)
			if ((mp->m_flag & MDELETED) == f)
				return(mp - &message[0] + 1);
		printf("No applicable messages\n");
		return(-1);

	case '.':
		/* 
		 * Current message.
		 */
		m = dot - &message[0] + 1;
		if ((dot->m_flag & MDELETED) != f) {
			printf("%d: Inappropriate message\n", m);
			return(-1);
		}
		return(m);

	default:
		printf("Unknown metachar (%c)\n", c);
		return(-1);
	}
}