1 /* $OpenBSD: read.c,v 1.7 2003/06/03 02:56:17 millert Exp $ */
2 /* $NetBSD: read.c,v 1.4 1994/11/23 07:42:07 jtc Exp $ */
3
4 /*-
5 * Copyright (c) 1991, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Edward Sze-Tyan Wang.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #ifndef lint
37 #if 0
38 static char sccsid[] = "@(#)read.c 8.1 (Berkeley) 6/6/93";
39 #endif
40 static char rcsid[] = "$OpenBSD: read.c,v 1.7 2003/06/03 02:56:17 millert Exp $";
41 #endif /* not lint */
42
43 #include <sys/types.h>
44 #include <sys/stat.h>
45
46 #include <err.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <unistd.h>
53
54 #include "extern.h"
55
56 /*
57 * bytes -- read bytes to an offset from the end and display.
58 *
59 * This is the function that reads to a byte offset from the end of the input,
60 * storing the data in a wrap-around buffer which is then displayed. If the
61 * rflag is set, the data is displayed in lines in reverse order, and this
62 * routine has the usual nastiness of trying to find the newlines. Otherwise,
63 * it is displayed from the character closest to the beginning of the input to
64 * the end.
65 *
66 * A non-zero return means an (non-fatal) error occurred.
67 *
68 */
69 int
bytes(fp,off)70 bytes(fp, off)
71 FILE *fp;
72 off_t off;
73 {
74 int ch, len, tlen;
75 char *ep, *p, *t;
76 int wrap;
77 char *sp;
78
79 if ((sp = p = malloc(off)) == NULL)
80 err(1, NULL);
81
82 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) {
83 *p = ch;
84 if (++p == ep) {
85 wrap = 1;
86 p = sp;
87 }
88 }
89 if (ferror(fp)) {
90 ierr();
91 return(1);
92 }
93
94 if (rflag) {
95 for (t = p - 1, len = 0; t >= sp; --t, ++len)
96 if (*t == '\n' && len) {
97 WR(t + 1, len);
98 len = 0;
99 }
100 if (wrap) {
101 tlen = len;
102 for (t = ep - 1, len = 0; t >= p; --t, ++len)
103 if (*t == '\n') {
104 if (len) {
105 WR(t + 1, len);
106 len = 0;
107 }
108 if (tlen) {
109 WR(sp, tlen);
110 tlen = 0;
111 }
112 }
113 if (len)
114 WR(t + 1, len);
115 if (tlen)
116 WR(sp, tlen);
117 }
118 } else {
119 if (wrap && (len = ep - p))
120 WR(p, len);
121 if ((len = p - sp))
122 WR(sp, len);
123 }
124 return(0);
125 }
126
127 /*
128 * lines -- read lines to an offset from the end and display.
129 *
130 * This is the function that reads to a line offset from the end of the input,
131 * storing the data in an array of buffers which is then displayed. If the
132 * rflag is set, the data is displayed in lines in reverse order, and this
133 * routine has the usual nastiness of trying to find the newlines. Otherwise,
134 * it is displayed from the line closest to the beginning of the input to
135 * the end.
136 *
137 * A non-zero return means an (non-fatal) error occurred.
138 *
139 */
140 int
lines(fp,off)141 lines(fp, off)
142 FILE *fp;
143 off_t off;
144 {
145 struct {
146 u_int blen;
147 u_int len;
148 char *l;
149 } *lines;
150 int ch;
151 char *p = NULL;
152 int blen, cnt, recno, wrap;
153 char *sp = NULL;
154
155 if ((lines = calloc(off, sizeof(*lines))) == NULL)
156 err(1, NULL);
157
158 blen = cnt = recno = wrap = 0;
159
160 while ((ch = getc(fp)) != EOF) {
161 if (++cnt > blen) {
162 if ((sp = realloc(sp, blen += 1024)) == NULL)
163 err(1, NULL);
164 p = sp + cnt - 1;
165 }
166 *p++ = ch;
167 if (ch == '\n') {
168 if (lines[recno].blen < cnt) {
169 lines[recno].blen = cnt + 256;
170 if ((lines[recno].l = realloc(lines[recno].l,
171 lines[recno].blen)) == NULL)
172 err(1, NULL);
173 }
174 memcpy(lines[recno].l, sp, (lines[recno].len = cnt));
175 cnt = 0;
176 p = sp;
177 if (++recno == off) {
178 wrap = 1;
179 recno = 0;
180 }
181 }
182 }
183 if (ferror(fp)) {
184 ierr();
185 return(1);
186 }
187 if (cnt) {
188 lines[recno].l = sp;
189 lines[recno].len = cnt;
190 if (++recno == off) {
191 wrap = 1;
192 recno = 0;
193 }
194 }
195
196 if (rflag) {
197 for (cnt = recno - 1; cnt >= 0; --cnt)
198 WR(lines[cnt].l, lines[cnt].len);
199 if (wrap)
200 for (cnt = off - 1; cnt >= recno; --cnt)
201 WR(lines[cnt].l, lines[cnt].len);
202 } else {
203 if (wrap)
204 for (cnt = recno; cnt < off; ++cnt)
205 WR(lines[cnt].l, lines[cnt].len);
206 for (cnt = 0; cnt < recno; ++cnt)
207 WR(lines[cnt].l, lines[cnt].len);
208 }
209 return(0);
210 }
211