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/types.h>
34 #include <sys/stat.h>
35
36 #include <err.h>
37 #include <errno.h>
38 #include <fcntl.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <strings.h>
43 #include <unistd.h>
44
45 #include "extern.h"
46
47 /*
48 * bytes -- read bytes to an offset from the end and display.
49 *
50 * This is the function that reads to a byte offset from the end of the input,
51 * storing the data in a wrap-around buffer which is then displayed. If the
52 * rflag is set, the data is displayed in lines in reverse order, and this
53 * routine has the usual nastiness of trying to find the newlines. Otherwise,
54 * it is displayed from the character closest to the beginning of the input to
55 * the end.
56 */
57 int
bytes(FILE * fp,const char * fn,off_t off)58 bytes(FILE *fp, const char *fn, off_t off)
59 {
60 int ch, len, tlen;
61 char *ep, *p, *t;
62 int wrap;
63 char *sp;
64
65 if ((sp = p = malloc(off)) == NULL)
66 err(1, "malloc");
67
68 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF; ) {
69 *p = ch;
70 if (++p == ep) {
71 wrap = 1;
72 p = sp;
73 }
74 }
75 if (ferror(fp)) {
76 ierr(fn);
77 free(sp);
78 return (1);
79 }
80
81 if (rflag) {
82 for (t = p - 1, len = 0; t >= sp; --t, ++len)
83 if (*t == '\n' && len) {
84 WR(t + 1, len);
85 len = 0;
86 }
87 if (wrap) {
88 tlen = len;
89 for (t = ep - 1, len = 0; t >= p; --t, ++len)
90 if (*t == '\n') {
91 if (len) {
92 WR(t + 1, len);
93 len = 0;
94 }
95 if (tlen) {
96 WR(sp, tlen);
97 tlen = 0;
98 }
99 }
100 if (len)
101 WR(t + 1, len);
102 if (tlen)
103 WR(sp, tlen);
104 }
105 } else {
106 if (wrap && (len = ep - p))
107 WR(p, len);
108 len = p - sp;
109 if (len)
110 WR(sp, len);
111 }
112
113 free(sp);
114 return (0);
115 }
116
117 /*
118 * lines -- read lines to an offset from the end and display.
119 *
120 * This is the function that reads to a line offset from the end of the input,
121 * storing the data in an array of buffers which is then displayed. If the
122 * rflag is set, the data is displayed in lines in reverse order, and this
123 * routine has the usual nastiness of trying to find the newlines. Otherwise,
124 * it is displayed from the line closest to the beginning of the input to
125 * the end.
126 */
127 int
lines(FILE * fp,const char * fn,off_t off)128 lines(FILE *fp, const char *fn, off_t off)
129 {
130 struct {
131 int blen;
132 uint_t len;
133 char *l;
134 } *llines;
135 int ch, rc;
136 char *p, *sp;
137 int blen, cnt, recno, wrap;
138
139 if ((llines = malloc(off * sizeof (*llines))) == NULL)
140 err(1, "malloc");
141 bzero(llines, off * sizeof (*llines));
142 p = sp = NULL;
143 blen = cnt = recno = wrap = 0;
144 rc = 0;
145
146 while ((ch = getc(fp)) != EOF) {
147 if (++cnt > blen) {
148 if ((sp = realloc(sp, blen += 1024)) == NULL)
149 err(1, "realloc");
150 p = sp + cnt - 1;
151 }
152 *p++ = ch;
153 if (ch == '\n') {
154 if ((int)llines[recno].blen < cnt) {
155 llines[recno].blen = cnt + 256;
156 if ((llines[recno].l = realloc(llines[recno].l,
157 llines[recno].blen)) == NULL)
158 err(1, "realloc");
159 }
160 bcopy(sp, llines[recno].l, llines[recno].len = cnt);
161 cnt = 0;
162 p = sp;
163 if (++recno == off) {
164 wrap = 1;
165 recno = 0;
166 }
167 }
168 }
169 if (ferror(fp)) {
170 ierr(fn);
171 rc = 1;
172 goto done;
173 }
174 if (cnt) {
175 llines[recno].l = sp;
176 sp = NULL;
177 llines[recno].len = cnt;
178 if (++recno == off) {
179 wrap = 1;
180 recno = 0;
181 }
182 }
183
184 if (rflag) {
185 for (cnt = recno - 1; cnt >= 0; --cnt)
186 WR(llines[cnt].l, llines[cnt].len);
187 if (wrap)
188 for (cnt = off - 1; cnt >= recno; --cnt)
189 WR(llines[cnt].l, llines[cnt].len);
190 } else {
191 if (wrap)
192 for (cnt = recno; cnt < off; ++cnt)
193 WR(llines[cnt].l, llines[cnt].len);
194 for (cnt = 0; cnt < recno; ++cnt)
195 WR(llines[cnt].l, llines[cnt].len);
196 }
197 done:
198 for (cnt = 0; cnt < off; cnt++)
199 free(llines[cnt].l);
200 free(sp);
201 free(llines);
202 return (rc);
203 }
204