read.c revision 17826
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 <err.h> 50#include "extern.h" 51 52/* 53 * bytes -- read bytes to an offset from the end and display. 54 * 55 * This is the function that reads to a byte offset from the end of the input, 56 * storing the data in a wrap-around buffer which is then displayed. If the 57 * rflag is set, the data is displayed in lines in reverse order, and this 58 * routine has the usual nastiness of trying to find the newlines. Otherwise, 59 * it is displayed from the character closest to the beginning of the input to 60 * the end. 61 */ 62int 63bytes(fp, off) 64 register FILE *fp; 65 off_t off; 66{ 67 register int ch, len, tlen; 68 register char *ep, *p, *t; 69 int wrap; 70 char *sp; 71 72 if ((sp = p = malloc(off)) == NULL) 73 err(1, "malloc"); 74 75 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) { 76 *p = ch; 77 if (++p == ep) { 78 wrap = 1; 79 p = sp; 80 } 81 } 82 if (ferror(fp)) { 83 ierr(); 84 return 1; 85 } 86 87 if (rflag) { 88 for (t = p - 1, len = 0; t >= sp; --t, ++len) 89 if (*t == '\n' && len) { 90 WR(t + 1, len); 91 len = 0; 92 } 93 if (wrap) { 94 tlen = len; 95 for (t = ep - 1, len = 0; t >= p; --t, ++len) 96 if (*t == '\n') { 97 if (len) { 98 WR(t + 1, len); 99 len = 0; 100 } 101 if (tlen) { 102 WR(sp, tlen); 103 tlen = 0; 104 } 105 } 106 if (len) 107 WR(t + 1, len); 108 if (tlen) 109 WR(sp, tlen); 110 } 111 } else { 112 if (wrap && (len = ep - p)) 113 WR(p, len); 114 if (len = p - sp) 115 WR(sp, len); 116 } 117 return 0; 118} 119 120/* 121 * lines -- read lines to an offset from the end and display. 122 * 123 * This is the function that reads to a line offset from the end of the input, 124 * storing the data in an array of buffers which is then displayed. If the 125 * rflag is set, the data is displayed in lines in reverse order, and this 126 * routine has the usual nastiness of trying to find the newlines. Otherwise, 127 * it is displayed from the line closest to the beginning of the input to 128 * the end. 129 */ 130int 131lines(fp, off) 132 register FILE *fp; 133 off_t off; 134{ 135 struct { 136 u_int blen; 137 u_int len; 138 char *l; 139 } *lines; 140 register int ch; 141 register char *p; 142 int blen, cnt, recno, wrap; 143 char *sp; 144 145 if ((lines = malloc(off * sizeof(*lines))) == NULL) 146 err(1, "malloc"); 147 bzero(lines, off * sizeof(*lines)); 148 sp = NULL; 149 blen = cnt = recno = wrap = 0; 150 151 while ((ch = getc(fp)) != EOF) { 152 if (++cnt > blen) { 153 if ((sp = realloc(sp, blen += 1024)) == NULL) 154 err(1, "realloc"); 155 p = sp + cnt - 1; 156 } 157 *p++ = ch; 158 if (ch == '\n') { 159 if (lines[recno].blen < cnt) { 160 lines[recno].blen = cnt + 256; 161 if ((lines[recno].l = realloc(lines[recno].l, 162 lines[recno].blen)) == NULL) 163 err(1, "realloc"); 164 } 165 bcopy(sp, lines[recno].l, lines[recno].len = cnt); 166 cnt = 0; 167 p = sp; 168 if (++recno == off) { 169 wrap = 1; 170 recno = 0; 171 } 172 } 173 } 174 if (ferror(fp)) { 175 ierr(); 176 return 1; 177 } 178 if (cnt) { 179 lines[recno].l = sp; 180 lines[recno].len = cnt; 181 if (++recno == off) { 182 wrap = 1; 183 recno = 0; 184 } 185 } 186 187 if (rflag) { 188 for (cnt = recno - 1; cnt >= 0; --cnt) 189 WR(lines[cnt].l, lines[cnt].len); 190 if (wrap) 191 for (cnt = off - 1; cnt >= recno; --cnt) 192 WR(lines[cnt].l, lines[cnt].len); 193 } else { 194 if (wrap) 195 for (cnt = recno; cnt < off; ++cnt) 196 WR(lines[cnt].l, lines[cnt].len); 197 for (cnt = 0; cnt < recno; ++cnt) 198 WR(lines[cnt].l, lines[cnt].len); 199 } 200 return 0; 201} 202