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 * 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#include <sys/cdefs.h> 38 39__FBSDID("$FreeBSD$"); 40 41#ifndef lint 42static const char sccsid[] = "@(#)read.c 8.1 (Berkeley) 6/6/93"; 43#endif 44 45#include <sys/types.h> 46#include <sys/stat.h> 47 48#include <err.h> 49#include <errno.h> 50#include <fcntl.h> 51#include <stdio.h> 52#include <stdlib.h> 53#include <string.h> 54#include <unistd.h> 55 56#include "extern.h" 57 58/* 59 * bytes -- read bytes to an offset from the end and display. 60 * 61 * This is the function that reads to a byte offset from the end of the input, 62 * storing the data in a wrap-around buffer which is then displayed. If the 63 * rflag is set, the data is displayed in lines in reverse order, and this 64 * routine has the usual nastiness of trying to find the newlines. Otherwise, 65 * it is displayed from the character closest to the beginning of the input to 66 * the end. 67 */ 68int 69bytes(FILE *fp, off_t off) 70{ 71 int ch, len, tlen; 72 char *ep, *p, *t; 73 int wrap; 74 char *sp; 75 76 if ((sp = p = malloc(off)) == NULL) 77 err(1, "malloc"); 78 79 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) { 80 *p = ch; 81 if (++p == ep) { 82 wrap = 1; 83 p = sp; 84 } 85 } 86 if (ferror(fp)) { 87 ierr(); 88 free(sp); 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 len = p - sp; 120 if (len) 121 WR(sp, len); 122 } 123 124 free(sp); 125 return 0; 126} 127 128/* 129 * lines -- read lines to an offset from the end and display. 130 * 131 * This is the function that reads to a line offset from the end of the input, 132 * storing the data in an array of buffers which is then displayed. If the 133 * rflag is set, the data is displayed in lines in reverse order, and this 134 * routine has the usual nastiness of trying to find the newlines. Otherwise, 135 * it is displayed from the line closest to the beginning of the input to 136 * the end. 137 */ 138int 139lines(FILE *fp, off_t off) 140{ 141 struct { 142 int blen; 143 u_int len; 144 char *l; 145 } *llines; 146 int ch, rc; 147 char *p, *sp; 148 int blen, cnt, recno, wrap; 149 150 if ((llines = malloc(off * sizeof(*llines))) == NULL) 151 err(1, "malloc"); 152 bzero(llines, off * sizeof(*llines)); 153 sp = NULL; 154 blen = cnt = recno = wrap = 0; 155 rc = 0; 156 157 while ((ch = getc(fp)) != EOF) { 158 if (++cnt > blen) { 159 if ((sp = realloc(sp, blen += 1024)) == NULL) 160 err(1, "realloc"); 161 p = sp + cnt - 1; 162 } 163 *p++ = ch; 164 if (ch == '\n') { 165 if ((int)llines[recno].blen < cnt) { 166 llines[recno].blen = cnt + 256; 167 if ((llines[recno].l = realloc(llines[recno].l, 168 llines[recno].blen)) == NULL) 169 err(1, "realloc"); 170 } 171 bcopy(sp, llines[recno].l, llines[recno].len = cnt); 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 rc = 1; 183 goto done; 184 } 185 if (cnt) { 186 llines[recno].l = sp; 187 sp = NULL; 188 llines[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(llines[cnt].l, llines[cnt].len); 198 if (wrap) 199 for (cnt = off - 1; cnt >= recno; --cnt) 200 WR(llines[cnt].l, llines[cnt].len); 201 } else { 202 if (wrap) 203 for (cnt = recno; cnt < off; ++cnt) 204 WR(llines[cnt].l, llines[cnt].len); 205 for (cnt = 0; cnt < recno; ++cnt) 206 WR(llines[cnt].l, llines[cnt].len); 207 } 208done: 209 for (cnt = 0; cnt < off; cnt++) 210 free(llines[cnt].l); 211 free(sp); 212 free(llines); 213 return (rc); 214} 215