2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
8 * Edward Sze-Tyan Wang.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
40 static const char sccsid[] = "@(#)read.c 8.1 (Berkeley) 6/6/93";
43 #include <sys/types.h>
57 * bytes -- read bytes to an offset from the end and display.
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
67 bytes(FILE *fp, const char *fn, off_t off)
74 if ((sp = p = malloc(off)) == NULL)
77 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) {
91 for (t = p - 1, len = 0; t >= sp; --t, ++len)
92 if (*t == '\n' && len) {
98 for (t = ep - 1, len = 0; t >= p; --t, ++len)
115 if (wrap && (len = ep - p))
127 * lines -- read lines to an offset from the end and display.
129 * This is the function that reads to a line offset from the end of the input,
130 * storing the data in an array of buffers which is then displayed. If the
131 * rflag is set, the data is displayed in lines in reverse order, and this
132 * routine has the usual nastiness of trying to find the newlines. Otherwise,
133 * it is displayed from the line closest to the beginning of the input to
137 lines(FILE *fp, const char *fn, off_t off)
146 int blen, cnt, recno, wrap;
148 if ((llines = calloc(off, sizeof(*llines))) == NULL)
151 blen = cnt = recno = wrap = 0;
154 while ((ch = getc(fp)) != EOF) {
156 if ((sp = realloc(sp, blen += 1024)) == NULL)
162 if ((int)llines[recno].blen < cnt) {
163 llines[recno].blen = cnt + 256;
164 if ((llines[recno].l = realloc(llines[recno].l,
165 llines[recno].blen)) == NULL)
168 bcopy(sp, llines[recno].l, llines[recno].len = cnt);
171 if (++recno == off) {
183 llines[recno].l = sp;
185 llines[recno].len = cnt;
186 if (++recno == off) {
193 for (cnt = recno - 1; cnt >= 0; --cnt)
194 WR(llines[cnt].l, llines[cnt].len);
196 for (cnt = off - 1; cnt >= recno; --cnt)
197 WR(llines[cnt].l, llines[cnt].len);
200 for (cnt = recno; cnt < off; ++cnt)
201 WR(llines[cnt].l, llines[cnt].len);
202 for (cnt = 0; cnt < recno; ++cnt)
203 WR(llines[cnt].l, llines[cnt].len);
206 for (cnt = 0; cnt < off; cnt++)