tty_subr.c

基于组件方式开发操作系统的OSKIT源代码

}

/*
 * Add a character to the end of a clist. Return -1 is no
 * more clists, or 0 for success.
 */
int
putc(chr, clistp)
	int chr;
	struct clist *clistp;
{
	struct cblock *cblockp;
	int s;

	s = spltty();

	if (clistp->c_cl == NULL) {
		if (clistp->c_cbreserved < 1) {
			splx(s);
			printf("putc to a clist with no reserved cblocks\n");
			return (-1);		/* nothing done */
		}
		cblockp = cblock_alloc();
		clistp->c_cbcount = 1;
		clistp->c_cf = clistp->c_cl = cblockp->c_info;
		clistp->c_cc = 0;
	} else {
		cblockp = (struct cblock *)((long)clistp->c_cl & ~CROUND);
		if (((long)clistp->c_cl & CROUND) == 0) {
			struct cblock *prev = (cblockp - 1);

			if (clistp->c_cbcount >= clistp->c_cbreserved) {
				if (clistp->c_cbcount >= clistp->c_cbmax
				    || cslushcount <= 0) {
					splx(s);
					return (-1);
				}
				--cslushcount;
			}
			cblockp = cblock_alloc();
			clistp->c_cbcount++;
			prev->c_next = cblockp;
			clistp->c_cl = cblockp->c_info;
		}
	}

	/*
	 * If this character is quoted, set the quote bit, if not, clear it.
	 */
	if (chr & TTY_QUOTE) {
		setbit(cblockp->c_quote, clistp->c_cl - (char *)cblockp->c_info);
		/*
		 * Use one of the spare quote bits to record that something
		 * may be quoted.
		 */
		setbit(cblockp->c_quote, CBQSIZE * NBBY - 1);
	} else
		clrbit(cblockp->c_quote, clistp->c_cl - (char *)cblockp->c_info);

	*clistp->c_cl++ = chr;
	clistp->c_cc++;

	splx(s);
	return (0);
}

/*
 * Copy data from linear buffer to clist chain. Return the
 * number of characters not copied.
 */
int
b_to_q(src, amount, clistp)
	char *src;
	int amount;
	struct clist *clistp;
{
	struct cblock *cblockp;
	char *firstbyte, *lastbyte;
	u_char startmask, endmask;
	int startbit, endbit, num_between, numc;
	int s;

	/*
	 * Avoid allocating an initial cblock and then not using it.
	 * c_cc == 0 must imply c_cbount == 0.
	 */
	if (amount <= 0)
		return (amount);

	s = spltty();

	/*
	 * If there are no cblocks assigned to this clist yet,
	 * then get one.
	 */
	if (clistp->c_cl == NULL) {
		if (clistp->c_cbreserved < 1) {
			splx(s);
			printf("b_to_q to a clist with no reserved cblocks.\n");
			return (amount);	/* nothing done */
		}
		cblockp = cblock_alloc();
		clistp->c_cbcount = 1;
		clistp->c_cf = clistp->c_cl = cblockp->c_info;
		clistp->c_cc = 0;
	} else {
		cblockp = (struct cblock *)((long)clistp->c_cl & ~CROUND);
	}

	while (amount) {
		/*
		 * Get another cblock if needed.
		 */
		if (((long)clistp->c_cl & CROUND) == 0) {
			struct cblock *prev = cblockp - 1;

			if (clistp->c_cbcount >= clistp->c_cbreserved) {
				if (clistp->c_cbcount >= clistp->c_cbmax
				    || cslushcount <= 0) {
					splx(s);
					return (amount);
				}
				--cslushcount;
			}
			cblockp = cblock_alloc();
			clistp->c_cbcount++;
			prev->c_next = cblockp;
			clistp->c_cl = cblockp->c_info;
		}

		/*
		 * Copy a chunk of the linear buffer up to the end
		 * of this cblock.
		 */
		numc = min(amount, (char *)(cblockp + 1) - clistp->c_cl);
		bcopy(src, clistp->c_cl, numc);

		/*
		 * Clear quote bits if they aren't known to be clear.
		 * The following could probably be made into a seperate
		 * "bitzero()" routine, but why bother?
		 */
		if (isset(cblockp->c_quote, CBQSIZE * NBBY - 1)) {
			startbit = clistp->c_cl - (char *)cblockp->c_info;
			endbit = startbit + numc - 1;

			firstbyte = (u_char *)cblockp->c_quote + (startbit / NBBY);
			lastbyte = (u_char *)cblockp->c_quote + (endbit / NBBY);

			/*
			 * Calculate mask of bits to preserve in first and
			 * last bytes.
			 */
			startmask = NBBY - (startbit % NBBY);
			startmask = 0xff >> startmask;
			endmask = (endbit % NBBY);
			endmask = 0xff << (endmask + 1);

			if (firstbyte != lastbyte) {
				*firstbyte &= startmask;
				*lastbyte &= endmask;

				num_between = lastbyte - firstbyte - 1;
				if (num_between)
					bzero(firstbyte + 1, num_between);
			} else {
				*firstbyte &= (startmask | endmask);
			}
		}

		/*
		 * ...and update pointer for the next chunk.
		 */
		src += numc;
		clistp->c_cl += numc;
		clistp->c_cc += numc;
		amount -= numc;
		/*
		 * If we go through the loop again, it's always
		 * for data in the next cblock, so by adding one (cblock),
		 * (which makes the pointer 1 beyond the end of this
		 * cblock) we prepare for the assignment of 'prev'
		 * above.
		 */
		cblockp += 1;

	}

	splx(s);
	return (amount);
}

/*
 * Get the next character in the clist. Store it at dst. Don't
 * advance any clist pointers, but return a pointer to the next
 * character position.
 */
char *
nextc(clistp, cp, dst)
	struct clist *clistp;
	char *cp;
	int *dst;
{
	struct cblock *cblockp;

	++cp;
	/*
	 * See if the next character is beyond the end of
	 * the clist.
	 */
	if (clistp->c_cc && (cp != clistp->c_cl)) {
		/*
		 * If the next character is beyond the end of this
		 * cblock, advance to the next cblock.
		 */
		if (((long)cp & CROUND) == 0)
			cp = ((struct cblock *)cp - 1)->c_next->c_info;
		cblockp = (struct cblock *)((long)cp & ~CROUND);

		/*
		 * Get the character. Set the quote flag if this character
		 * is quoted.
		 */
		*dst = (u_char)*cp | (isset(cblockp->c_quote, cp - (char *)cblockp->c_info) ? TTY_QUOTE : 0);

		return (cp);
	}

	return (NULL);
}

/*
 * "Unput" a character from a clist.
 */
int
unputc(clistp)
	struct clist *clistp;
{
	struct cblock *cblockp = 0, *cbp = 0;
	int s;
	int chr = -1;


	s = spltty();

	if (clistp->c_cc) {
		--clistp->c_cc;
		--clistp->c_cl;

		chr = (u_char)*clistp->c_cl;

		cblockp = (struct cblock *)((long)clistp->c_cl & ~CROUND);

		/*
		 * Set quote flag if this character was quoted.
		 */
		if (isset(cblockp->c_quote, (u_char *)clistp->c_cl - cblockp->c_info))
			chr |= TTY_QUOTE;

		/*
		 * If all of the characters have been unput in this
		 * cblock, then find the previous one and free this
		 * one.
		 */
		if (clistp->c_cc && (clistp->c_cl <= (char *)cblockp->c_info)) {
			cbp = (struct cblock *)((long)clistp->c_cf & ~CROUND);

			while (cbp->c_next != cblockp)
				cbp = cbp->c_next;

			/*
			 * When the previous cblock is at the end, the 'last'
			 * pointer always points (invalidly) one past.
			 */
			clistp->c_cl = (char *)(cbp+1);
			cblock_free(cblockp);
			if (--clistp->c_cbcount >= clistp->c_cbreserved)
				++cslushcount;
			cbp->c_next = NULL;
		}
	}

	/*
	 * If there are no more characters on the list, then
	 * free the last cblock.
	 */
	if ((clistp->c_cc == 0) && clistp->c_cl) {
		cblockp = (struct cblock *)((long)clistp->c_cl & ~CROUND);
		cblock_free(cblockp);
		if (--clistp->c_cbcount >= clistp->c_cbreserved)
			++cslushcount;
		clistp->c_cf = clistp->c_cl = NULL;
	}

	splx(s);
	return (chr);
}

/*
 * Move characters in source clist to destination clist,
 * preserving quote bits.
 */
void
catq(src_clistp, dest_clistp)
	struct clist *src_clistp, *dest_clistp;
{
	int chr, s;

	s = spltty();
	/*
	 * If the destination clist is empty (has no cblocks atttached),
	 * and there are no possible complications with the resource counters,
	 * then we simply assign the current clist to the destination.
	 */
	if (!dest_clistp->c_cf
	    && src_clistp->c_cbcount <= src_clistp->c_cbmax
	    && src_clistp->c_cbcount <= dest_clistp->c_cbmax) {
		dest_clistp->c_cf = src_clistp->c_cf;
		dest_clistp->c_cl = src_clistp->c_cl;
		src_clistp->c_cf = src_clistp->c_cl = NULL;

		dest_clistp->c_cc = src_clistp->c_cc;
		src_clistp->c_cc = 0;
		dest_clistp->c_cbcount = src_clistp->c_cbcount;
		src_clistp->c_cbcount = 0;

		splx(s);
		return;
	}

	splx(s);

	/*
	 * XXX  This should probably be optimized to more than one
	 * character at a time.
	 */
	while ((chr = getc(src_clistp)) != -1)
		putc(chr, dest_clistp);
}