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1 | /*- |
2 | * Copyright (c) 1991 The Regents of the University of California. | |
3 | * 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 | * 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. | |
23 | * | |
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 | |
34 | * SUCH DAMAGE. | |
35 | */ | |
36 | ||
37 | #ifndef lint | |
38 | static char sccsid[] = "@(#)read.c 5.1 (Berkeley) 7/21/91"; | |
39 | #endif /* not lint */ | |
40 | ||
41 | #include <sys/types.h> | |
42 | #include <sys/stat.h> | |
43 | #include <fcntl.h> | |
44 | #include <errno.h> | |
45 | #include <unistd.h> | |
46 | #include <stdio.h> | |
47 | #include <stdlib.h> | |
48 | #include <string.h> | |
49 | #include "extern.h" | |
50 | ||
51 | /* | |
52 | * bytes -- read bytes to an offset from the end and display. | |
53 | * | |
54 | * This is the function that reads to a byte offset from the end of the input, | |
55 | * storing the data in a wrap-around buffer which is then displayed. If the | |
56 | * rflag is set, the data is displayed in lines in reverse order, and this | |
57 | * routine has the usual nastiness of trying to find the newlines. Otherwise, | |
58 | * it is displayed from the character closest to the beginning of the input to | |
59 | * the end. | |
60 | */ | |
61 | void | |
62 | bytes(fp, off) | |
63 | register FILE *fp; | |
64 | long off; | |
65 | { | |
66 | register int ch, len, tlen; | |
67 | register char *ep, *p, *t; | |
68 | int wrap; | |
69 | char *sp; | |
70 | ||
71 | if ((sp = p = malloc(off)) == NULL) | |
72 | err("%s", strerror(errno)); | |
73 | ||
74 | for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) { | |
75 | *p = ch; | |
76 | if (++p == ep) { | |
77 | wrap = 1; | |
78 | p = sp; | |
79 | } | |
80 | } | |
81 | if (ferror(fp)) | |
82 | ierr(); | |
83 | ||
84 | if (rflag) { | |
85 | for (t = p - 1, len = 0; t >= sp; --t, ++len) | |
86 | if (*t == '\n' && len) { | |
87 | WR(t + 1, len); | |
88 | len = 0; | |
89 | } | |
90 | if (wrap) { | |
91 | tlen = len; | |
92 | for (t = ep - 1, len = 0; t >= p; --t, ++len) | |
93 | if (*t == '\n') { | |
94 | if (len) { | |
95 | WR(t + 1, len); | |
96 | len = 0; | |
97 | } | |
98 | if (tlen) { | |
99 | WR(sp, tlen); | |
100 | tlen = 0; | |
101 | } | |
102 | } | |
103 | if (len) | |
104 | WR(t + 1, len); | |
105 | if (tlen) | |
106 | WR(sp, tlen); | |
107 | } | |
108 | } else { | |
109 | if (wrap && (len = ep - p)) | |
110 | WR(p, len); | |
111 | if (len = p - sp) | |
112 | WR(sp, len); | |
113 | } | |
114 | } | |
115 | ||
116 | /* | |
117 | * lines -- read lines to an offset from the end and display. | |
118 | * | |
119 | * This is the function that reads to a line offset from the end of the input, | |
120 | * storing the data in an array of buffers which is then displayed. If the | |
121 | * rflag is set, the data is displayed in lines in reverse order, and this | |
122 | * routine has the usual nastiness of trying to find the newlines. Otherwise, | |
123 | * it is displayed from the line closest to the beginning of the input to | |
124 | * the end. | |
125 | */ | |
126 | void | |
127 | lines(fp, off) | |
128 | register FILE *fp; | |
129 | long off; | |
130 | { | |
131 | struct { | |
132 | u_int blen; | |
133 | u_int len; | |
134 | char *l; | |
135 | } *lines; | |
136 | register int ch; | |
137 | register char *p; | |
138 | u_int blen, cnt, recno; | |
139 | int wrap; | |
140 | char *sp; | |
141 | ||
142 | if ((lines = malloc(off * sizeof(*lines))) == NULL) | |
143 | err("%s", strerror(errno)); | |
144 | ||
145 | sp = NULL; | |
146 | blen = cnt = recno = wrap = 0; | |
147 | ||
148 | while ((ch = getc(fp)) != EOF) { | |
149 | if (++cnt > blen) { | |
150 | if ((sp = realloc(sp, blen += 1024)) == NULL) | |
151 | err("%s", strerror(errno)); | |
152 | p = sp + cnt - 1; | |
153 | } | |
154 | *p++ = ch; | |
155 | if (ch == '\n') { | |
156 | if (lines[recno].blen < cnt) { | |
157 | lines[recno].blen = cnt + 256; | |
158 | if ((lines[recno].l = realloc(lines[recno].l, | |
159 | lines[recno].blen)) == NULL) | |
160 | err("%s", strerror(errno)); | |
161 | } | |
162 | bcopy(sp, lines[recno].l, lines[recno].len = cnt); | |
163 | cnt = 0; | |
164 | p = sp; | |
165 | if (++recno == off) { | |
166 | wrap = 1; | |
167 | recno = 0; | |
168 | } | |
169 | } | |
170 | } | |
171 | if (ferror(fp)) | |
172 | ierr(); | |
173 | if (cnt) { | |
174 | lines[recno].l = sp; | |
175 | lines[recno].len = cnt; | |
176 | if (++recno == off) { | |
177 | wrap = 1; | |
178 | recno = 0; | |
179 | } | |
180 | } | |
181 | ||
182 | if (rflag) { | |
183 | for (cnt = recno - 1; cnt >= 0; --cnt) | |
184 | WR(lines[cnt].l, lines[cnt].len); | |
185 | if (wrap) | |
186 | for (cnt = off - 1; cnt >= recno; --cnt) | |
187 | WR(lines[cnt].l, lines[cnt].len); | |
188 | } else { | |
189 | if (wrap) | |
190 | for (cnt = recno; cnt < off; ++cnt) | |
191 | WR(lines[cnt].l, lines[cnt].len); | |
192 | for (cnt = 0; cnt < recno; ++cnt) | |
193 | WR(lines[cnt].l, lines[cnt].len); | |
194 | } | |
195 | } |