2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Edward Sze-Tyan Wang.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
42 static const char sccsid[] = "@(#)read.c 8.1 (Berkeley) 6/6/93";
45 #include <sys/types.h>
59 * bytes -- read bytes to an offset from the end and display.
61 * This is the function that reads to a byte offset from the end of the input,
62 * storing the data in a wrap-around buffer which is then displayed. If the
63 * rflag is set, the data is displayed in lines in reverse order, and this
64 * routine has the usual nastiness of trying to find the newlines. Otherwise,
65 * it is displayed from the character closest to the beginning of the input to
69 bytes(FILE *fp, off_t off)
76 if ((sp = p = malloc(off)) == NULL)
79 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) {
92 for (t = p - 1, len = 0; t >= sp; --t, ++len)
93 if (*t == '\n' && len) {
99 for (t = ep - 1, len = 0; t >= p; --t, ++len)
116 if (wrap && (len = ep - p))
126 * lines -- read lines to an offset from the end and display.
128 * This is the function that reads to a line offset from the end of the input,
129 * storing the data in an array of buffers which is then displayed. If the
130 * rflag is set, the data is displayed in lines in reverse order, and this
131 * routine has the usual nastiness of trying to find the newlines. Otherwise,
132 * it is displayed from the line closest to the beginning of the input to
136 lines(FILE *fp, off_t off)
145 int blen, cnt, recno, wrap;
147 if ((llines = malloc(off * sizeof(*llines))) == NULL)
149 bzero(llines, off * sizeof(*llines));
151 blen = cnt = recno = wrap = 0;
153 while ((ch = getc(fp)) != EOF) {
155 if ((sp = realloc(sp, blen += 1024)) == NULL)
161 if ((int)llines[recno].blen < cnt) {
162 llines[recno].blen = cnt + 256;
163 if ((llines[recno].l = realloc(llines[recno].l,
164 llines[recno].blen)) == NULL)
167 bcopy(sp, llines[recno].l, llines[recno].len = cnt);
170 if (++recno == off) {
181 llines[recno].l = sp;
182 llines[recno].len = cnt;
183 if (++recno == off) {
190 for (cnt = recno - 1; cnt >= 0; --cnt)
191 WR(llines[cnt].l, llines[cnt].len);
193 for (cnt = off - 1; cnt >= recno; --cnt)
194 WR(llines[cnt].l, llines[cnt].len);
197 for (cnt = recno; cnt < off; ++cnt)
198 WR(llines[cnt].l, llines[cnt].len);
199 for (cnt = 0; cnt < recno; ++cnt)
200 WR(llines[cnt].l, llines[cnt].len);