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
|
/* $OpenBSD: read.c,v 1.10 2007/09/13 19:59:18 otto Exp $ */
/* $NetBSD: read.c,v 1.4 1994/11/23 07:42:07 jtc Exp $ */
/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Edward Sze-Tyan Wang.
*
* 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. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)read.c 8.1 (Berkeley) 6/6/93";
#endif
static char rcsid[] = "$OpenBSD: read.c,v 1.10 2007/09/13 19:59:18 otto Exp $";
#endif /* not lint */
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/limits.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "extern.h"
/*
* bytes -- read bytes to an offset from the end and display.
*
* This is the function that reads to a byte offset from the end of the input,
* storing the data in a wrap-around buffer which is then displayed. If the
* rflag is set, the data is displayed in lines in reverse order, and this
* routine has the usual nastiness of trying to find the newlines. Otherwise,
* it is displayed from the character closest to the beginning of the input to
* the end.
*
* A non-zero return means an (non-fatal) error occurred.
*
*/
int
bytes(FILE *fp, off_t off)
{
int ch;
size_t len, tlen;
char *ep, *p, *t;
int wrap;
char *sp;
if (off > SIZE_T_MAX)
errx(1, "offset too large");
if ((sp = p = malloc(off)) == NULL)
err(1, NULL);
for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) {
*p = ch;
if (++p == ep) {
wrap = 1;
p = sp;
}
}
if (ferror(fp)) {
ierr();
free(sp);
return(1);
}
if (rflag) {
for (t = p - 1, len = 0; t >= sp; --t, ++len)
if (*t == '\n' && len) {
WR(t + 1, len);
len = 0;
}
if (wrap) {
tlen = len;
for (t = ep - 1, len = 0; t >= p; --t, ++len)
if (*t == '\n') {
if (len) {
WR(t + 1, len);
len = 0;
}
if (tlen) {
WR(sp, tlen);
tlen = 0;
}
}
if (len)
WR(t + 1, len);
if (tlen)
WR(sp, tlen);
}
} else {
if (wrap && (len = ep - p))
WR(p, len);
if ((len = p - sp))
WR(sp, len);
}
free(sp);
return(0);
}
/*
* lines -- read lines to an offset from the end and display.
*
* This is the function that reads to a line offset from the end of the input,
* storing the data in an array of buffers which is then displayed. If the
* rflag is set, the data is displayed in lines in reverse order, and this
* routine has the usual nastiness of trying to find the newlines. Otherwise,
* it is displayed from the line closest to the beginning of the input to
* the end.
*
* A non-zero return means an (non-fatal) error occurred.
*
*/
int
lines(FILE *fp, off_t off)
{
struct {
size_t blen;
size_t len;
char *l;
} *lines;
int ch;
char *p = NULL;
int wrap;
size_t cnt, recno, blen, newsize;
char *sp = NULL, *newp = NULL;
if (off > SIZE_T_MAX)
errx(1, "offset too large");
if ((lines = calloc(off, sizeof(*lines))) == NULL)
err(1, NULL);
blen = cnt = recno = wrap = 0;
while ((ch = getc(fp)) != EOF) {
if (++cnt > blen) {
newsize = blen + 1024;
if ((newp = realloc(sp, newsize)) == NULL)
err(1, NULL);
sp = newp;
blen = newsize;
p = sp + cnt - 1;
}
*p++ = ch;
if (ch == '\n') {
if (lines[recno].blen < cnt) {
newsize = cnt + 256;
if ((newp = realloc(lines[recno].l,
newsize)) == NULL)
err(1, NULL);
lines[recno].l = newp;
lines[recno].blen = newsize;
}
memcpy(lines[recno].l, sp, (lines[recno].len = cnt));
cnt = 0;
p = sp;
if (++recno == off) {
wrap = 1;
recno = 0;
}
}
}
if (ferror(fp)) {
ierr();
return(1);
}
if (cnt) {
lines[recno].l = sp;
lines[recno].len = cnt;
if (++recno == off) {
wrap = 1;
recno = 0;
}
}
if (rflag) {
for (cnt = recno; cnt > 0; --cnt)
WR(lines[cnt - 1].l, lines[cnt - 1].len);
if (wrap)
for (cnt = off; cnt > recno; --cnt)
WR(lines[cnt - 1].l, lines[cnt - 1].len);
} else {
if (wrap)
for (cnt = recno; cnt < off; ++cnt)
WR(lines[cnt].l, lines[cnt].len);
for (cnt = 0; cnt < recno; ++cnt)
WR(lines[cnt].l, lines[cnt].len);
}
return(0);
}
|
