NetBSD/sys/kern/tty_ring.c

203 lines
5.5 KiB
C

/*
* Copyright (c) 1989, 1990, 1991, 1992 William F. Jolitz, TeleMuse
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This software is a component of "386BSD" developed by
* William F. Jolitz, TeleMuse.
* 4. Neither the name of the developer nor the name "386BSD"
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS A COMPONENT OF 386BSD DEVELOPED BY WILLIAM F. JOLITZ
* AND IS INTENDED FOR RESEARCH AND EDUCATIONAL PURPOSES ONLY. THIS
* SOFTWARE SHOULD NOT BE CONSIDERED TO BE A COMMERCIAL PRODUCT.
* THE DEVELOPER URGES THAT USERS WHO REQUIRE A COMMERCIAL PRODUCT
* NOT MAKE USE OF THIS WORK.
*
* FOR USERS WHO WISH TO UNDERSTAND THE 386BSD SYSTEM DEVELOPED
* BY WILLIAM F. JOLITZ, WE RECOMMEND THE USER STUDY WRITTEN
* REFERENCES SUCH AS THE "PORTING UNIX TO THE 386" SERIES
* (BEGINNING JANUARY 1991 "DR. DOBBS JOURNAL", USA AND BEGINNING
* JUNE 1991 "UNIX MAGAZIN", GERMANY) BY WILLIAM F. JOLITZ AND
* LYNNE GREER JOLITZ, AS WELL AS OTHER BOOKS ON UNIX AND THE
* ON-LINE 386BSD USER MANUAL BEFORE USE. A BOOK DISCUSSING THE INTERNALS
* OF 386BSD ENTITLED "386BSD FROM THE INSIDE OUT" WILL BE AVAILABLE LATE 1992.
*
* THIS SOFTWARE IS PROVIDED BY THE DEVELOPER ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE DEVELOPER BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
static char rcsid[] = "$Header: /cvsroot/src/sys/kern/Attic/tty_ring.c,v 1.2 1993/03/24 23:55:29 cgd Exp $";
#include "param.h"
#include "systm.h"
#include "buf.h"
#include "ioctl.h"
#include "tty.h"
/*
* XXX - put this in tty.h someday.
*/
size_t rb_write __P((struct ringb *to, char *buf, size_t nfrom));
putc(c, rbp) struct ringb *rbp;
{
char *nxtp;
/* ring buffer full? */
if ( (nxtp = RB_SUCC(rbp, rbp->rb_tl)) == rbp->rb_hd) return (-1);
/* stuff character */
*rbp->rb_tl = c;
rbp->rb_tl = nxtp;
return(0);
}
getc(rbp) struct ringb *rbp;
{
u_char c;
/* ring buffer empty? */
if (rbp->rb_hd == rbp->rb_tl) return(-1);
/* fetch character, locate next character */
c = *(u_char *) rbp->rb_hd;
rbp->rb_hd = RB_SUCC(rbp, rbp->rb_hd);
return (c);
}
nextc(cpp, rbp) struct ringb *rbp; char **cpp; {
if (*cpp == rbp->rb_tl) return (0);
else { char *cp;
cp = *cpp;
*cpp = RB_SUCC(rbp, cp);
return(*cp);
}
}
ungetc(c, rbp) struct ringb *rbp;
{
char *backp;
/* ring buffer full? */
if ( (backp = RB_PRED(rbp, rbp->rb_hd)) == rbp->rb_tl) return (-1);
rbp->rb_hd = backp;
/* stuff character */
*rbp->rb_hd = c;
return(0);
}
unputc(rbp) struct ringb *rbp;
{
char *backp;
int c;
/* ring buffer empty? */
if (rbp->rb_hd == rbp->rb_tl) return(-1);
/* backup buffer and dig out previous character */
backp = RB_PRED(rbp, rbp->rb_tl);
c = *(u_char *)backp;
rbp->rb_tl = backp;
return(c);
}
#define peekc(rbp) (*(rbp)->rb_hd)
initrb(rbp) struct ringb *rbp; {
rbp->rb_hd = rbp->rb_tl = rbp->rb_buf;
}
/*
* Example code for contiguous operations:
...
nc = RB_CONTIGPUT(&rb);
if (nc) {
if (nc > 9) nc = 9;
bcopy("ABCDEFGHI", rb.rb_tl, nc);
rb.rb_tl += nc;
rb.rb_tl = RB_ROLLOVER(&rb, rb.rb_tl);
}
...
...
nc = RB_CONTIGGET(&rb);
if (nc) {
if (nc > 79) nc = 79;
bcopy(rb.rb_hd, stringbuf, nc);
rb.rb_hd += nc;
rb.rb_hd = RB_ROLLOVER(&rb, rb.rb_hd);
stringbuf[nc] = 0;
printf("%s|", stringbuf);
}
...
*/
/*
* Concatenate ring buffers.
*/
catb(from, to)
struct ringb *from, *to;
{
size_t nfromleft;
size_t nfromright;
nfromright = RB_CONTIGGET(from);
rb_write(to, from->rb_hd, nfromright);
from->rb_hd += nfromright;
from->rb_hd = RB_ROLLOVER(from, from->rb_hd);
nfromleft = RB_CONTIGGET(from);
rb_write(to, from->rb_hd, nfromleft);
from->rb_hd += nfromleft;
}
/*
* Copy ordinary buffer to ring buffer, return count of what fitted.
*/
size_t rb_write(to, buf, nfrom)
struct ringb *to;
char *buf;
size_t nfrom;
{
char *toleft;
size_t ntoleft;
size_t ntoright;
ntoright = RB_CONTIGPUT(to);
if (nfrom < ntoright) {
bcopy(buf, to->rb_tl, nfrom);
to->rb_tl += nfrom;
return (nfrom);
}
bcopy(buf, to->rb_tl, ntoright);
nfrom -= ntoright;
toleft = to->rb_buf; /* fast RB_ROLLOVER */
ntoleft = to->rb_hd - toleft; /* fast RB_CONTIGPUT */
if (nfrom > ntoleft)
nfrom = ntoleft;
bcopy(buf + ntoright, toleft, nfrom);
to->rb_tl = toleft + nfrom;
return (ntoright + nfrom);
}