diff options
Diffstat (limited to 'sys/kern/tty_ring.c')
| -rw-r--r-- | sys/kern/tty_ring.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/sys/kern/tty_ring.c b/sys/kern/tty_ring.c new file mode 100644 index 000000000000..f4149e576214 --- /dev/null +++ b/sys/kern/tty_ring.c @@ -0,0 +1,202 @@ +/* + * 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. + * + * $Id: tty_ring.c,v 1.2 1993/10/16 15:25:01 rgrimes 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); +} |