bin/less/os.c

   1 /*
   2  * Copyright (C) 1984-2012  Mark Nudelman
   3  * Modified for use with illumos by Garrett D'Amore.
   4  * Copyright 2014 Garrett D'Amore <garrett@damore.org>
   5  *
   6  * You may distribute under the terms of either the GNU General Public
   7  * License or the Less License, as specified in the README file.
   8  *
   9  * For more information, see the README file.
  10  */
  11
  12 /*
  13  * Operating system dependent routines.
  14  *
  15  * Most of the stuff in here is based on Unix, but an attempt
  16  * has been made to make things work on other operating systems.
  17  * This will sometimes result in a loss of functionality, unless
  18  * someone rewrites code specifically for the new operating system.
  19  *
  20  * The makefile provides defines to decide whether various
  21  * Unix features are present.
  22  */
  23
  24 #include <errno.h>
  25 #include <signal.h>
  26 #include <time.h>
  27
  28 #include "less.h"
  29
  30 extern volatile sig_atomic_t sigs;
  31
  32 /*
  33  * Like read() system call, but is deliberately interruptible.
  34  */
  35 int
  36 iread(int fd, unsigned char *buf, unsigned int len)
  37 {
  38         int n;
  39
  40 start:
  41         flush(0);
  42         n = read(fd, buf, len);
  43         if (n < 0) {
  44                 /*
  45                  * Certain values of errno indicate we should just retry the
  46                  * read.
  47                  */
  48                 if (errno == EINTR)
  49                         return (READ_INTR);
  50                 if (errno == EAGAIN)
  51                         goto start;
  52                 return (-1);
  53         }
  54         return (n);
  55 }
  56
  57 /*
  58  * errno_message: Return an error message based on the value of "errno".
  59  */
  60 char *
  61 errno_message(char *filename)
  62 {
  63         return (easprintf("%s: %s", filename, strerror(errno)));
  64 }
  65
  66 static off_t
  67 muldiv(off_t val, off_t num, off_t den)
  68 {
  69         double v = (((double)val) * num) / den;
  70         return ((off_t)(v + 0.5));
  71 }
  72
  73 /*
  74  * Return the ratio of two off_t, as a percentage.
  75  * {{ Assumes a off_t is a long int. }}
  76  */
  77 int
  78 percentage(off_t num, off_t den)
  79 {
  80         return ((int)muldiv(num, (off_t)100, den));
  81 }
  82
  83 /*
  84  * Return the specified percentage of a off_t.
  85  */
  86 off_t
  87 percent_pos(off_t pos, int percent, long fraction)
  88 {
  89         /*
  90          * Change percent (parts per 100) to perden
  91          * (parts per NUM_FRAC_DENOM).
  92          */
  93         off_t perden = (percent * (NUM_FRAC_DENOM / 100)) + (fraction / 100);
  94
  95         if (perden == 0)
  96                 return (0);
  97         return (muldiv(pos, perden, (off_t)NUM_FRAC_DENOM));
  98 }