1 /* $NetBSD: read.c,v 1.8 2002/06/14 00:47:41 wiz Exp $ */ 2 3 /*- 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Edward Sze-Tyan Wang. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #ifndef lint 41 #if 0 42 static char sccsid[] = "@(#)read.c 8.1 (Berkeley) 6/6/93"; 43 #endif 44 __RCSID("$NetBSD: read.c,v 1.8 2002/06/14 00:47:41 wiz Exp $"); 45 #endif /* not lint */ 46 47 #include <sys/types.h> 48 #include <sys/stat.h> 49 #include <fcntl.h> 50 #include <errno.h> 51 #include <unistd.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include "extern.h" 56 57 /* 58 * bytes -- read bytes to an offset from the end and display. 59 * 60 * This is the function that reads to a byte offset from the end of the input, 61 * storing the data in a wrap-around buffer which is then displayed. If the 62 * rflag is set, the data is displayed in lines in reverse order, and this 63 * routine has the usual nastiness of trying to find the newlines. Otherwise, 64 * it is displayed from the character closest to the beginning of the input to 65 * the end. 66 * 67 * Non-zero return means than a (non-fatal) error occurred. 68 */ 69 int 70 bytes(FILE *fp, __off_t off) 71 { 72 int ch, len, tlen; 73 char *ep, *p, *t; 74 int wrap; 75 char *sp; 76 77 if ((sp = p = malloc(off)) == NULL) 78 err(1, "%s", strerror(errno)); 79 80 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) { 81 *p = ch; 82 if (++p == ep) { 83 wrap = 1; 84 p = sp; 85 } 86 } 87 if (ferror(fp)) { 88 ierr(); 89 return (1); 90 } 91 92 if (rflag) { 93 for (t = p - 1, len = 0; t >= sp; --t, ++len) 94 if (*t == '\n' && len) { 95 WR(t + 1, len); 96 len = 0; 97 } 98 if (wrap) { 99 tlen = len; 100 for (t = ep - 1, len = 0; t >= p; --t, ++len) 101 if (*t == '\n') { 102 if (len) { 103 WR(t + 1, len); 104 len = 0; 105 } 106 if (tlen) { 107 WR(sp, tlen); 108 tlen = 0; 109 } 110 } 111 if (len) 112 WR(t + 1, len); 113 if (tlen) 114 WR(sp, tlen); 115 } 116 } else { 117 if (wrap && (len = ep - p)) 118 WR(p, len); 119 if ((len = p - sp) == 0) 120 WR(sp, len); 121 } 122 return (0); 123 } 124 125 /* 126 * lines -- read lines to an offset from the end and display. 127 * 128 * This is the function that reads to a line offset from the end of the input, 129 * storing the data in an array of buffers which is then displayed. If the 130 * rflag is set, the data is displayed in lines in reverse order, and this 131 * routine has the usual nastiness of trying to find the newlines. Otherwise, 132 * it is displayed from the line closest to the beginning of the input to 133 * the end. 134 * 135 * Non-zero return means than a (non-fatal) error occurred. 136 */ 137 int 138 lines(FILE *fp, __off_t off) 139 { 140 struct { 141 u_int blen; 142 u_int len; 143 char *l; 144 } *lines; 145 int ch; 146 char *p; 147 int blen, cnt, recno, wrap; 148 char *sp; 149 150 p = NULL; 151 if ((lines = malloc(off * sizeof(*lines))) == NULL) 152 err(1, "%s", strerror(errno)); 153 154 memset(lines, 0, sizeof(*lines) * off); 155 156 sp = NULL; 157 blen = cnt = recno = wrap = 0; 158 159 while ((ch = getc(fp)) != EOF) { 160 if (++cnt > blen) { 161 if ((sp = realloc(sp, blen += 1024)) == NULL) 162 err(1, "%s", strerror(errno)); 163 p = sp + cnt - 1; 164 } 165 *p++ = ch; 166 if (ch == '\n') { 167 if (lines[recno].blen < cnt) { 168 lines[recno].blen = cnt + 256; 169 if ((lines[recno].l = realloc(lines[recno].l, 170 lines[recno].blen)) == NULL) 171 err(1, "%s", strerror(errno)); 172 } 173 memmove(lines[recno].l, sp, lines[recno].len = cnt); 174 cnt = 0; 175 p = sp; 176 if (++recno == off) { 177 wrap = 1; 178 recno = 0; 179 } 180 } 181 } 182 if (ferror(fp)) { 183 ierr(); 184 return (1); 185 } 186 if (cnt) { 187 lines[recno].l = sp; 188 lines[recno].len = cnt; 189 if (++recno == off) { 190 wrap = 1; 191 recno = 0; 192 } 193 } 194 195 if (rflag) { 196 for (cnt = recno - 1; cnt >= 0; --cnt) 197 WR(lines[cnt].l, lines[cnt].len); 198 if (wrap) 199 for (cnt = off - 1; cnt >= recno; --cnt) 200 WR(lines[cnt].l, lines[cnt].len); 201 } else { 202 if (wrap) 203 for (cnt = recno; cnt < off; ++cnt) 204 WR(lines[cnt].l, lines[cnt].len); 205 for (cnt = 0; cnt < recno; ++cnt) 206 WR(lines[cnt].l, lines[cnt].len); 207 } 208 return (0); 209 } 210