1 /* $NetBSD: read.c,v 1.7 1999/07/21 06:38:50 cgd 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 1.7 1999/07/21 06:38:50 cgd 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(fp, off) 71 FILE *fp; 72 off_t off; 73 { 74 int ch, len, tlen; 75 char *ep, *p, *t; 76 int wrap; 77 char *sp; 78 79 if ((sp = p = malloc(off)) == NULL) 80 err(1, "%s", strerror(errno)); 81 82 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) { 83 *p = ch; 84 if (++p == ep) { 85 wrap = 1; 86 p = sp; 87 } 88 } 89 if (ferror(fp)) { 90 ierr(); 91 return (1); 92 } 93 94 if (rflag) { 95 for (t = p - 1, len = 0; t >= sp; --t, ++len) 96 if (*t == '\n' && len) { 97 WR(t + 1, len); 98 len = 0; 99 } 100 if (wrap) { 101 tlen = len; 102 for (t = ep - 1, len = 0; t >= p; --t, ++len) 103 if (*t == '\n') { 104 if (len) { 105 WR(t + 1, len); 106 len = 0; 107 } 108 if (tlen) { 109 WR(sp, tlen); 110 tlen = 0; 111 } 112 } 113 if (len) 114 WR(t + 1, len); 115 if (tlen) 116 WR(sp, tlen); 117 } 118 } else { 119 if (wrap && (len = ep - p)) 120 WR(p, len); 121 if ((len = p - sp) == 0) 122 WR(sp, len); 123 } 124 return (0); 125 } 126 127 /* 128 * lines -- read lines to an offset from the end and display. 129 * 130 * This is the function that reads to a line offset from the end of the input, 131 * storing the data in an array of buffers which is then displayed. If the 132 * rflag is set, the data is displayed in lines in reverse order, and this 133 * routine has the usual nastiness of trying to find the newlines. Otherwise, 134 * it is displayed from the line closest to the beginning of the input to 135 * the end. 136 * 137 * Non-zero return means than a (non-fatal) error occurred. 138 */ 139 int 140 lines(fp, off) 141 FILE *fp; 142 off_t off; 143 { 144 struct { 145 u_int blen; 146 u_int len; 147 char *l; 148 } *lines; 149 int ch; 150 char *p; 151 int blen, cnt, recno, wrap; 152 char *sp; 153 154 p = NULL; 155 if ((lines = malloc(off * sizeof(*lines))) == NULL) 156 err(1, "%s", strerror(errno)); 157 158 memset(lines, 0, sizeof(*lines) * off); 159 160 sp = NULL; 161 blen = cnt = recno = wrap = 0; 162 163 while ((ch = getc(fp)) != EOF) { 164 if (++cnt > blen) { 165 if ((sp = realloc(sp, blen += 1024)) == NULL) 166 err(1, "%s", strerror(errno)); 167 p = sp + cnt - 1; 168 } 169 *p++ = ch; 170 if (ch == '\n') { 171 if (lines[recno].blen < cnt) { 172 lines[recno].blen = cnt + 256; 173 if ((lines[recno].l = realloc(lines[recno].l, 174 lines[recno].blen)) == NULL) 175 err(1, "%s", strerror(errno)); 176 } 177 memmove(lines[recno].l, sp, lines[recno].len = cnt); 178 cnt = 0; 179 p = sp; 180 if (++recno == off) { 181 wrap = 1; 182 recno = 0; 183 } 184 } 185 } 186 if (ferror(fp)) { 187 ierr(); 188 return (1); 189 } 190 if (cnt) { 191 lines[recno].l = sp; 192 lines[recno].len = cnt; 193 if (++recno == off) { 194 wrap = 1; 195 recno = 0; 196 } 197 } 198 199 if (rflag) { 200 for (cnt = recno - 1; cnt >= 0; --cnt) 201 WR(lines[cnt].l, lines[cnt].len); 202 if (wrap) 203 for (cnt = off - 1; cnt >= recno; --cnt) 204 WR(lines[cnt].l, lines[cnt].len); 205 } else { 206 if (wrap) 207 for (cnt = recno; cnt < off; ++cnt) 208 WR(lines[cnt].l, lines[cnt].len); 209 for (cnt = 0; cnt < recno; ++cnt) 210 WR(lines[cnt].l, lines[cnt].len); 211 } 212 return (0); 213 } 214