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