1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
/* $OpenBSD: os.c,v 1.4 2001/11/19 19:02:14 mpech Exp $ */
/*
* 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;
{
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;
{
char *p;
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);
}
|
