Annotation of src/usr.bin/tail/read.c, Revision 1.5
1.5 ! mpech 1: /* $OpenBSD: read.c,v 1.4 2000/06/23 17:04:46 ericj 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
1.5 ! mpech 44: static char rcsid[] = "$OpenBSD: read.c,v 1.4 2000/06/23 17:04:46 ericj 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.
1.4 ericj 69: *
1.5 ! mpech 70: * A non-zero return means an (non-fatal) error occurred.
1.4 ericj 71: *
1.1 deraadt 72: */
1.4 ericj 73: int
1.1 deraadt 74: bytes(fp, off)
75: register FILE *fp;
76: off_t off;
77: {
78: register int ch, len, tlen;
79: register char *ep, *p, *t;
80: int wrap;
81: char *sp;
82:
83: if ((sp = p = malloc(off)) == NULL)
1.3 millert 84: err(1, NULL);
1.1 deraadt 85:
86: for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) {
87: *p = ch;
88: if (++p == ep) {
89: wrap = 1;
90: p = sp;
91: }
92: }
93: if (ferror(fp)) {
94: ierr();
1.4 ericj 95: return(1);
1.1 deraadt 96: }
97:
98: if (rflag) {
99: for (t = p - 1, len = 0; t >= sp; --t, ++len)
100: if (*t == '\n' && len) {
101: WR(t + 1, len);
102: len = 0;
103: }
104: if (wrap) {
105: tlen = len;
106: for (t = ep - 1, len = 0; t >= p; --t, ++len)
107: if (*t == '\n') {
108: if (len) {
109: WR(t + 1, len);
110: len = 0;
111: }
112: if (tlen) {
113: WR(sp, tlen);
114: tlen = 0;
115: }
116: }
117: if (len)
118: WR(t + 1, len);
119: if (tlen)
120: WR(sp, tlen);
121: }
122: } else {
123: if (wrap && (len = ep - p))
124: WR(p, len);
1.3 millert 125: if ((len = p - sp))
1.1 deraadt 126: WR(sp, len);
127: }
1.4 ericj 128: return(0);
1.1 deraadt 129: }
130:
131: /*
132: * lines -- read lines to an offset from the end and display.
133: *
134: * This is the function that reads to a line offset from the end of the input,
135: * storing the data in an array of buffers which is then displayed. If the
136: * rflag is set, the data is displayed in lines in reverse order, and this
137: * routine has the usual nastiness of trying to find the newlines. Otherwise,
138: * it is displayed from the line closest to the beginning of the input to
139: * the end.
1.4 ericj 140: *
1.5 ! mpech 141: * A non-zero return means an (non-fatal) error occurred.
1.4 ericj 142: *
1.1 deraadt 143: */
1.4 ericj 144: int
1.1 deraadt 145: lines(fp, off)
146: register FILE *fp;
147: off_t off;
148: {
149: struct {
150: u_int blen;
151: u_int len;
152: char *l;
153: } *lines;
154: register int ch;
1.3 millert 155: register char *p = NULL;
1.1 deraadt 156: int blen, cnt, recno, wrap;
1.3 millert 157: char *sp = NULL;
1.1 deraadt 158:
1.3 millert 159: if ((lines = calloc(off, sizeof(*lines))) == NULL)
160: err(1, NULL);
1.1 deraadt 161:
162: blen = cnt = recno = wrap = 0;
163:
164: while ((ch = getc(fp)) != EOF) {
165: if (++cnt > blen) {
166: if ((sp = realloc(sp, blen += 1024)) == NULL)
1.3 millert 167: err(1, NULL);
1.1 deraadt 168: p = sp + cnt - 1;
169: }
170: *p++ = ch;
171: if (ch == '\n') {
172: if (lines[recno].blen < cnt) {
173: lines[recno].blen = cnt + 256;
174: if ((lines[recno].l = realloc(lines[recno].l,
175: lines[recno].blen)) == NULL)
1.3 millert 176: err(1, NULL);
1.1 deraadt 177: }
1.3 millert 178: memcpy(lines[recno].l, sp, (lines[recno].len = cnt));
1.1 deraadt 179: cnt = 0;
180: p = sp;
181: if (++recno == off) {
182: wrap = 1;
183: recno = 0;
184: }
185: }
186: }
187: if (ferror(fp)) {
188: ierr();
1.4 ericj 189: return(1);
1.1 deraadt 190: }
191: if (cnt) {
192: lines[recno].l = sp;
193: lines[recno].len = cnt;
194: if (++recno == off) {
195: wrap = 1;
196: recno = 0;
197: }
198: }
199:
200: if (rflag) {
201: for (cnt = recno - 1; cnt >= 0; --cnt)
202: WR(lines[cnt].l, lines[cnt].len);
203: if (wrap)
204: for (cnt = off - 1; cnt >= recno; --cnt)
205: WR(lines[cnt].l, lines[cnt].len);
206: } else {
207: if (wrap)
208: for (cnt = recno; cnt < off; ++cnt)
209: WR(lines[cnt].l, lines[cnt].len);
210: for (cnt = 0; cnt < recno; ++cnt)
211: WR(lines[cnt].l, lines[cnt].len);
212: }
1.4 ericj 213: return(0);
1.1 deraadt 214: }
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