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/*
* Copyright (c) 1984,1985,1989,1994,1995 Mark Nudelman
* 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 in the documentation and/or other materials provided with
* the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/*
* Operating system dependent routines.
*
* Most of the stuff in here is based on Unix, but an attempt
* has been made to make things work on other operating systems.
* This will sometimes result in a loss of functionality, unless
* someone rewrites code specifically for the new operating system.
*
* The makefile provides defines to decide whether various
* Unix features are present.
*/
#include "less.h"
#include <limits.h>
#include <signal.h>
#include <setjmp.h>
#if HAVE_TIME_H
#include <time.h>
#endif
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#if HAVE_VALUES_H
#include <values.h>
#endif
#if HAVE_TIME_T
#define time_type time_t
#else
#define time_type long
#endif
/*
* BSD setjmp() saves (and longjmp() restores) the signal mask.
* This costs a system call or two per setjmp(), so if possible we clear the
* signal mask with sigsetmask(), and use _setjmp()/_longjmp() instead.
* On other systems, setjmp() doesn't affect the signal mask and so
* _setjmp() does not exist; we just use setjmp().
*/
#if HAVE__SETJMP && HAVE_SIGSETMASK
#define SET_JUMP _setjmp
#define LONG_JUMP _longjmp
#else
#define SET_JUMP setjmp
#define LONG_JUMP longjmp
#endif
public int reading;
static jmp_buf read_label;
/*
* Like read() system call, but is deliberately interruptible.
* A call to intread() from a signal handler will interrupt
* any pending iread().
*/
public int
iread(fd, buf, len)
int fd;
char *buf;
unsigned int len;
{
register int n;
#if MSOFTC
if (kbhit())
{
int c;
c = getch();
if (c == '\003')
return (READ_INTR);
ungetch(c);
}
#endif
if (SET_JUMP(read_label))
{
/*
* We jumped here from intread.
*/
reading = 0;
#if HAVE_SIGSETMASK
sigsetmask(0);
#endif
return (READ_INTR);
}
flush();
reading = 1;
n = read(fd, buf, len);
reading = 0;
if (n < 0)
return (-1);
return (n);
}
/*
* Interrupt a pending iread().
*/
public void
intread()
{
LONG_JUMP(read_label, 1);
}
/*
* Return the current time.
*/
#if HAVE_TIME
public long
get_time()
{
time_type t;
time(&t);
return (t);
}
#endif
#if !HAVE_STRERROR
/*
* Local version of strerror, if not available from the system.
*/
static char *
strerror(err)
int err;
{
#if HAVE_SYS_ERRLIST
static char buf[16];
extern char *sys_errlist[];
extern int sys_nerr;
if (err < sys_nerr)
return sys_errlist[err];
sprintf(buf, "Error %d", err);
return buf;
#else
return ("cannot open");
#endif
}
#endif
/*
* errno_message: Return an error message based on the value of "errno".
*/
public char *
errno_message(filename)
char *filename;
{
register char *p;
register char *m;
#if HAVE_ERRNO
extern int errno;
p = strerror(errno);
#else
p = "cannot open";
#endif
m = (char *) ecalloc(strlen(filename) + strlen(p) + 3, sizeof(char));
sprintf(m, "%s: %s", filename, p);
return (m);
}
/*
* Return the largest possible number that can fit in a POSITION.
*/
#ifdef QUAD_MAX
static POSITION
get_maxpos()
{
return (QUAD_MAX);
}
#else
static POSITION
get_maxpos()
{
POSITION n, n2;
/*
* Keep doubling n until we overflow.
* {{ This actually only returns the largest power of two that
* can fit in a POSITION, but percentage() doesn't really need
* it any more accurate than that. }}
*/
n2 = 128; /* Hopefully no maxpos is less than 128! */
do {
n = n2;
n2 *= 2;
} while (n2 / 2 == n);
return (n);
}
#endif
/*
* Return the ratio of two POSITIONs, as a percentage.
*/
public int
percentage(num, den)
POSITION num, den;
{
static POSITION maxpos100 = 0;
if (maxpos100 == 0)
maxpos100 = get_maxpos() / 100;
if (num > maxpos100)
return (num / (den/100));
else
return (100*num / den);
}
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