read.c revision 11411
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#ifndef lint 38static char sccsid[] = "@(#)read.c 8.1 (Berkeley) 6/6/93"; 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 */ 61void 62bytes(fp, off) 63 register FILE *fp; 64 off_t 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(1, "%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 return; 84 } 85 86 if (rflag) { 87 for (t = p - 1, len = 0; t >= sp; --t, ++len) 88 if (*t == '\n' && len) { 89 WR(t + 1, len); 90 len = 0; 91 } 92 if (wrap) { 93 tlen = len; 94 for (t = ep - 1, len = 0; t >= p; --t, ++len) 95 if (*t == '\n') { 96 if (len) { 97 WR(t + 1, len); 98 len = 0; 99 } 100 if (tlen) { 101 WR(sp, tlen); 102 tlen = 0; 103 } 104 } 105 if (len) 106 WR(t + 1, len); 107 if (tlen) 108 WR(sp, tlen); 109 } 110 } else { 111 if (wrap && (len = ep - p)) 112 WR(p, len); 113 if (len = p - sp) 114 WR(sp, len); 115 } 116} 117 118/* 119 * lines -- read lines to an offset from the end and display. 120 * 121 * This is the function that reads to a line offset from the end of the input, 122 * storing the data in an array of buffers which is then displayed. If the 123 * rflag is set, the data is displayed in lines in reverse order, and this 124 * routine has the usual nastiness of trying to find the newlines. Otherwise, 125 * it is displayed from the line closest to the beginning of the input to 126 * the end. 127 */ 128void 129lines(fp, off) 130 register FILE *fp; 131 off_t off; 132{ 133 struct { 134 u_int blen; 135 u_int len; 136 char *l; 137 } *lines; 138 register int ch; 139 register char *p; 140 int blen, cnt, recno, wrap; 141 char *sp; 142 143 if ((lines = malloc(off * sizeof(*lines))) == NULL) 144 err(1, "%s", strerror(errno)); 145 bzero(lines, off * sizeof(*lines)); 146 sp = NULL; 147 blen = cnt = recno = wrap = 0; 148 149 while ((ch = getc(fp)) != EOF) { 150 if (++cnt > blen) { 151 if ((sp = realloc(sp, blen += 1024)) == NULL) 152 err(1, "%s", strerror(errno)); 153 p = sp + cnt - 1; 154 } 155 *p++ = ch; 156 if (ch == '\n') { 157 if (lines[recno].blen < cnt) { 158 lines[recno].blen = cnt + 256; 159 if ((lines[recno].l = realloc(lines[recno].l, 160 lines[recno].blen)) == NULL) 161 err(1, "%s", strerror(errno)); 162 } 163 bcopy(sp, lines[recno].l, lines[recno].len = cnt); 164 cnt = 0; 165 p = sp; 166 if (++recno == off) { 167 wrap = 1; 168 recno = 0; 169 } 170 } 171 } 172 if (ferror(fp)) { 173 ierr(); 174 return; 175 } 176 if (cnt) { 177 lines[recno].l = sp; 178 lines[recno].len = cnt; 179 if (++recno == off) { 180 wrap = 1; 181 recno = 0; 182 } 183 } 184 185 if (rflag) { 186 for (cnt = recno - 1; cnt >= 0; --cnt) 187 WR(lines[cnt].l, lines[cnt].len); 188 if (wrap) 189 for (cnt = off - 1; cnt >= recno; --cnt) 190 WR(lines[cnt].l, lines[cnt].len); 191 } else { 192 if (wrap) 193 for (cnt = recno; cnt < off; ++cnt) 194 WR(lines[cnt].l, lines[cnt].len); 195 for (cnt = 0; cnt < recno; ++cnt) 196 WR(lines[cnt].l, lines[cnt].len); 197 } 198} 199