Annotation of src/usr.bin/tail/read.c, Revision 1.3
1.3 ! millert 1: /* $OpenBSD: read.c,v 1.2 1996/06/26 05:40:16 deraadt Exp $ */
1.1 deraadt 2: /* $NetBSD: read.c,v 1.4 1994/11/23 07:42:07 jtc Exp $ */
3:
4: /*-
5: * Copyright (c) 1991, 1993
6: * The Regents of the University of California. All rights reserved.
7: *
8: * This code is derived from software contributed to Berkeley by
9: * Edward Sze-Tyan Wang.
10: *
11: * Redistribution and use in source and binary forms, with or without
12: * modification, are permitted provided that the following conditions
13: * are met:
14: * 1. Redistributions of source code must retain the above copyright
15: * notice, this list of conditions and the following disclaimer.
16: * 2. Redistributions in binary form must reproduce the above copyright
17: * notice, this list of conditions and the following disclaimer in the
18: * documentation and/or other materials provided with the distribution.
19: * 3. All advertising materials mentioning features or use of this software
20: * must display the following acknowledgement:
21: * This product includes software developed by the University of
22: * California, Berkeley and its contributors.
23: * 4. Neither the name of the University nor the names of its contributors
24: * may be used to endorse or promote products derived from this software
25: * without specific prior written permission.
26: *
27: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37: * SUCH DAMAGE.
38: */
39:
40: #ifndef lint
41: #if 0
42: static char sccsid[] = "@(#)read.c 8.1 (Berkeley) 6/6/93";
43: #endif
1.3 ! millert 44: static char rcsid[] = "$OpenBSD: read.c,v 1.2 1996/06/26 05:40:16 deraadt Exp $";
1.1 deraadt 45: #endif /* not lint */
46:
47: #include <sys/types.h>
48: #include <sys/stat.h>
1.3 ! millert 49:
! 50: #include <err.h>
! 51: #include <errno.h>
1.1 deraadt 52: #include <fcntl.h>
53: #include <stdio.h>
54: #include <stdlib.h>
55: #include <string.h>
1.3 ! millert 56: #include <unistd.h>
! 57:
1.1 deraadt 58: #include "extern.h"
59:
60: /*
61: * bytes -- read bytes to an offset from the end and display.
62: *
63: * This is the function that reads to a byte offset from the end of the input,
64: * storing the data in a wrap-around buffer which is then displayed. If the
65: * rflag is set, the data is displayed in lines in reverse order, and this
66: * routine has the usual nastiness of trying to find the newlines. Otherwise,
67: * it is displayed from the character closest to the beginning of the input to
68: * the end.
69: */
70: void
71: bytes(fp, off)
72: register FILE *fp;
73: off_t off;
74: {
75: register int ch, len, tlen;
76: register char *ep, *p, *t;
77: int wrap;
78: char *sp;
79:
80: if ((sp = p = malloc(off)) == NULL)
1.3 ! millert 81: err(1, NULL);
1.1 deraadt 82:
83: for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) {
84: *p = ch;
85: if (++p == ep) {
86: wrap = 1;
87: p = sp;
88: }
89: }
90: if (ferror(fp)) {
91: ierr();
92: return;
93: }
94:
95: if (rflag) {
96: for (t = p - 1, len = 0; t >= sp; --t, ++len)
97: if (*t == '\n' && len) {
98: WR(t + 1, len);
99: len = 0;
100: }
101: if (wrap) {
102: tlen = len;
103: for (t = ep - 1, len = 0; t >= p; --t, ++len)
104: if (*t == '\n') {
105: if (len) {
106: WR(t + 1, len);
107: len = 0;
108: }
109: if (tlen) {
110: WR(sp, tlen);
111: tlen = 0;
112: }
113: }
114: if (len)
115: WR(t + 1, len);
116: if (tlen)
117: WR(sp, tlen);
118: }
119: } else {
120: if (wrap && (len = ep - p))
121: WR(p, len);
1.3 ! millert 122: if ((len = p - sp))
1.1 deraadt 123: WR(sp, len);
124: }
125: }
126:
127: /*
128: * lines -- read lines to an offset from the end and display.
129: *
130: * This is the function that reads to a line offset from the end of the input,
131: * storing the data in an array of buffers which is then displayed. If the
132: * rflag is set, the data is displayed in lines in reverse order, and this
133: * routine has the usual nastiness of trying to find the newlines. Otherwise,
134: * it is displayed from the line closest to the beginning of the input to
135: * the end.
136: */
137: void
138: lines(fp, off)
139: register FILE *fp;
140: off_t off;
141: {
142: struct {
143: u_int blen;
144: u_int len;
145: char *l;
146: } *lines;
147: register int ch;
1.3 ! millert 148: register char *p = NULL;
1.1 deraadt 149: int blen, cnt, recno, wrap;
1.3 ! millert 150: char *sp = NULL;
1.1 deraadt 151:
1.3 ! millert 152: if ((lines = calloc(off, sizeof(*lines))) == NULL)
! 153: err(1, NULL);
1.1 deraadt 154:
155: blen = cnt = recno = wrap = 0;
156:
157: while ((ch = getc(fp)) != EOF) {
158: if (++cnt > blen) {
159: if ((sp = realloc(sp, blen += 1024)) == NULL)
1.3 ! millert 160: err(1, NULL);
1.1 deraadt 161: p = sp + cnt - 1;
162: }
163: *p++ = ch;
164: if (ch == '\n') {
165: if (lines[recno].blen < cnt) {
166: lines[recno].blen = cnt + 256;
167: if ((lines[recno].l = realloc(lines[recno].l,
168: lines[recno].blen)) == NULL)
1.3 ! millert 169: err(1, NULL);
1.1 deraadt 170: }
1.3 ! millert 171: memcpy(lines[recno].l, sp, (lines[recno].len = cnt));
1.1 deraadt 172: cnt = 0;
173: p = sp;
174: if (++recno == off) {
175: wrap = 1;
176: recno = 0;
177: }
178: }
179: }
180: if (ferror(fp)) {
181: ierr();
182: return;
183: }
184: if (cnt) {
185: lines[recno].l = sp;
186: lines[recno].len = cnt;
187: if (++recno == off) {
188: wrap = 1;
189: recno = 0;
190: }
191: }
192:
193: if (rflag) {
194: for (cnt = recno - 1; cnt >= 0; --cnt)
195: WR(lines[cnt].l, lines[cnt].len);
196: if (wrap)
197: for (cnt = off - 1; cnt >= recno; --cnt)
198: WR(lines[cnt].l, lines[cnt].len);
199: } else {
200: if (wrap)
201: for (cnt = recno; cnt < off; ++cnt)
202: WR(lines[cnt].l, lines[cnt].len);
203: for (cnt = 0; cnt < recno; ++cnt)
204: WR(lines[cnt].l, lines[cnt].len);
205: }
206: }
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