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ttyio.c
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C/C++ Source or Header
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1988-07-25
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6KB
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266 lines
/*
* Name: MicroEMACS
* System V terminal I/O.
* Version: 0
* Last edit: Tue Aug 26 23:57:57 PDT 1986
* By: gonzo!daveb
* {sun, amdahl, mtxinu}!rtech!gonzo!daveb
*
* The functions in this file
* negotiate with the operating system for
* keyboard characters, and write characters to
* the display in a barely buffered fashion.
*
* This version goes along with tty/termcap/tty.c.
* Terminal size is determined there, rather than here, and
* this does not open the termcap file
*/
#include "def.h"
#include <sys/types.h>
#include <fcntl.h>
#include <termio.h>
#define NOBUF 512 /* Output buffer size. */
char obuf[NOBUF]; /* Output buffer. */
int nobuf; /* buffer count */
static struct termio ot; /* entry state of the terminal */
static struct termio nt; /* editor's terminal state */
static int ttyactivep = FALSE; /* terminal in editor mode? */
static int ttysavedp = FALSE; /* terminal state saved? */
int nrow; /* Terminal size, rows. */
int ncol; /* Terminal size, columns. */
/* These are used to implement typeahead on System V */
int kbdflgs; /* saved keyboard fd flags */
int kbdpoll; /* in O_NDELAY mode */
int kbdqp; /* there is a char in kbdq */
char kbdq; /* char we've already read */
/*
* This function gets called once, to set up
* the terminal channel. This version turns off flow
* control. This may be wrong for your system, but no
* good solution has really been found (daveb).
*/
ttopen()
{
register char *cp;
extern char *getenv();
if (ttyactivep)
return;
if( !ttysavedp )
{
if (ioctl(0, TCGETA, &ot) < 0)
abort();
nt = ot; /* save entry state */
nt.c_cc[VMIN] = 1; /* one character read is OK */
nt.c_cc[VTIME] = 0; /* Never time out. */
nt.c_iflag |= IGNBRK;
nt.c_iflag &= ~( ICRNL | INLCR | ISTRIP | IXON | IXOFF );
nt.c_oflag &= ~OPOST;
nt.c_cflag |= CS8; /* allow 8th bit on input */
nt.c_cflag &= ~PARENB; /* Don't check parity */
nt.c_lflag &= ~( ECHO | ICANON | ISIG );
kbdpoll = (((kbdflgs = fcntl(0, F_GETFL, 0)) & O_NDELAY) != 0);
ttysavedp = TRUE;
}
if (ioctl(0, TCSETAF, &nt) < 0)
abort();
/* This really belongs in tty/termcap... */
if ((cp=getenv("TERMCAP")) == NULL
|| (nrow=getvalue(cp, "li")) <= 0
|| (ncol=getvalue(cp, "co")) <= 0) {
nrow = 24;
ncol = 80;
}
if (nrow > NROW) /* Don't crash if the */
nrow = NROW; /* termcap entry is */
if (ncol > NCOL) /* too big. */
ncol = NCOL;
ttyactivep = TRUE;
}
/*
* This routine scans a string, which is
* actually the return value of a getenv call for the TERMCAP
* variable, looking for numeric parameter "name". Return the value
* if found. Return -1 if not there. Assume that "name" is 2
* characters long. This limited use of the TERMCAP lets us find
* out the size of a window on the X display.
*/
getvalue(cp, name)
register char *cp;
register char *name;
{
for (;;) {
while (*cp!=0 && *cp!=':')
++cp;
if (*cp++ == 0) /* Not found. */
return (-1);
if (cp[0]==name[0] && cp[1]==name[1] && cp[2]=='#')
return (atoi(cp+3)); /* Stops on ":". */
}
}
/*
* This function gets called just
* before we go back home to the shell. Put all of
* the terminal parameters back.
*/
ttclose()
{
if(!ttysavedp || !ttyactivep)
return;
ttflush();
if (ioctl(0, TCSETAF, &ot) < 0 || fcntl( 0, F_SETFL, kbdflgs ) < 0)
abort();
ttyactivep = FALSE;
}
/*
* Write character to the display.
* Characters are buffered up, to make things
* a little bit more efficient.
*/
ttputc(c)
{
if (nobuf >= NOBUF)
ttflush();
obuf[nobuf++] = c;
}
/*
* Flush output.
*/
ttflush()
{
if (nobuf != 0) {
write(1, obuf, nobuf);
nobuf = 0;
}
}
/*
* Read character from terminal.
* All 8 bits are returned, so that you can use
* a multi-national terminal.
*
* If keyboard 'queue' already has typeahead from a typeahead() call,
* just return it. Otherwise, make sure we are in blocking i/o mode
* and read a character.
*/
ttgetc()
{
if( kbdqp )
kbdqp = FALSE;
else
{
if( kbdpoll && fcntl( 0, F_SETFL, kbdflgs ) < 0 )
abort();
kbdpoll = FALSE;
while (read(0, &kbdq, 1) != 1)
;
}
return ( kbdq & 0xff );
}
/*
* Return non-FALSE if typeahead is pending.
*
* If already got unread typeahead, do nothing.
* Otherwise, set keyboard to O_NDELAY if not already, and try
* a one character read.
*/
typeahead()
{
if( !kbdqp )
{
if( !kbdpoll && fcntl( 0, F_SETFL, kbdflgs | O_NDELAY ) < 0 )
abort();
kbdpoll = TRUE;
kbdqp = (1 == read( 0, &kbdq, 1 ));
}
return ( kbdqp );
}
/*
* panic: print error and die, leaving core file.
* Don't know why this is needed (daveb).
*/
panic(s)
char *s;
{
fprintf(stderr, "%s\r\n", s);
abort();
}
/*
** This should check the size of the window, and reset if needed.
*/
setttysize()
{
#ifdef TIOCGWINSZ
auto struct winsize wsize;
if (ioctl(0, TIOCGWINSZ, (char *) &wsize) == 0) {
nrow = wsize . ws_row;
ncol = wsize . ws_col;
} else
#endif
if ((nrow=tgetnum ("li")) <= 0
|| (ncol=tgetnum ("co")) <= 0) {
nrow = 24;
ncol = 80;
}
if (nrow > NROW) /* Don't crash if the */
nrow = NROW; /* termcap entry is */
if (ncol > NCOL) /* too big. */
ncol = NCOL;
}
#ifndef NO_DPROMPT
#include <signal.h>
#include <setjmp.h>
static jmp_buf tohere;
static alrm()
{
longjmp(tohere, -1);
}
/*
* Return TRUE if we wait without doing anything, else return FALSE.
*/
ttwait()
{
int alrm();
if (kbdqp)
return FALSE; /* already pending input */
if (setjmp(tohere))
return TRUE; /* timeout on read if here */
signal(SIGALRM, alrm); alarm(2);
kbdqp = (1 == read(0, &kbdq, 1));
alarm(0);
return FALSE; /* successful read if here */
}
#endif NO_DPROMPT