read.c revision 1.4
1 /* $NetBSD: read.c,v 1.4 1994/11/23 07:42:07 jtc 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 #ifndef lint 40 #if 0 41 static char sccsid[] = "@(#)read.c 8.1 (Berkeley) 6/6/93"; 42 #endif 43 static char rcsid[] = "$NetBSD: read.c,v 1.4 1994/11/23 07:42:07 jtc Exp $"; 44 #endif /* not lint */ 45 46 #include <sys/types.h> 47 #include <sys/stat.h> 48 #include <fcntl.h> 49 #include <errno.h> 50 #include <unistd.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include "extern.h" 55 56 /* 57 * bytes -- read bytes to an offset from the end and display. 58 * 59 * This is the function that reads to a byte offset from the end of the input, 60 * storing the data in a wrap-around buffer which is then displayed. If the 61 * rflag is set, the data is displayed in lines in reverse order, and this 62 * routine has the usual nastiness of trying to find the newlines. Otherwise, 63 * it is displayed from the character closest to the beginning of the input to 64 * the end. 65 */ 66 void 67 bytes(fp, off) 68 register FILE *fp; 69 off_t off; 70 { 71 register int ch, len, tlen; 72 register char *ep, *p, *t; 73 int wrap; 74 char *sp; 75 76 if ((sp = p = malloc(off)) == NULL) 77 err(1, "%s", strerror(errno)); 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 return; 89 } 90 91 if (rflag) { 92 for (t = p - 1, len = 0; t >= sp; --t, ++len) 93 if (*t == '\n' && len) { 94 WR(t + 1, len); 95 len = 0; 96 } 97 if (wrap) { 98 tlen = len; 99 for (t = ep - 1, len = 0; t >= p; --t, ++len) 100 if (*t == '\n') { 101 if (len) { 102 WR(t + 1, len); 103 len = 0; 104 } 105 if (tlen) { 106 WR(sp, tlen); 107 tlen = 0; 108 } 109 } 110 if (len) 111 WR(t + 1, len); 112 if (tlen) 113 WR(sp, tlen); 114 } 115 } else { 116 if (wrap && (len = ep - p)) 117 WR(p, len); 118 if (len = p - sp) 119 WR(sp, len); 120 } 121 } 122 123 /* 124 * lines -- read lines to an offset from the end and display. 125 * 126 * This is the function that reads to a line offset from the end of the input, 127 * storing the data in an array of buffers which is then displayed. If the 128 * rflag is set, the data is displayed in lines in reverse order, and this 129 * routine has the usual nastiness of trying to find the newlines. Otherwise, 130 * it is displayed from the line closest to the beginning of the input to 131 * the end. 132 */ 133 void 134 lines(fp, off) 135 register FILE *fp; 136 off_t off; 137 { 138 struct { 139 u_int blen; 140 u_int len; 141 char *l; 142 } *lines; 143 register int ch; 144 register char *p; 145 int blen, cnt, recno, wrap; 146 char *sp; 147 148 if ((lines = malloc(off * sizeof(*lines))) == NULL) 149 err(1, "%s", strerror(errno)); 150 151 sp = NULL; 152 blen = cnt = recno = wrap = 0; 153 154 while ((ch = getc(fp)) != EOF) { 155 if (++cnt > blen) { 156 if ((sp = realloc(sp, blen += 1024)) == NULL) 157 err(1, "%s", strerror(errno)); 158 p = sp + cnt - 1; 159 } 160 *p++ = ch; 161 if (ch == '\n') { 162 if (lines[recno].blen < cnt) { 163 lines[recno].blen = cnt + 256; 164 if ((lines[recno].l = realloc(lines[recno].l, 165 lines[recno].blen)) == NULL) 166 err(1, "%s", strerror(errno)); 167 } 168 bcopy(sp, lines[recno].l, lines[recno].len = cnt); 169 cnt = 0; 170 p = sp; 171 if (++recno == off) { 172 wrap = 1; 173 recno = 0; 174 } 175 } 176 } 177 if (ferror(fp)) { 178 ierr(); 179 return; 180 } 181 if (cnt) { 182 lines[recno].l = sp; 183 lines[recno].len = cnt; 184 if (++recno == off) { 185 wrap = 1; 186 recno = 0; 187 } 188 } 189 190 if (rflag) { 191 for (cnt = recno - 1; cnt >= 0; --cnt) 192 WR(lines[cnt].l, lines[cnt].len); 193 if (wrap) 194 for (cnt = off - 1; cnt >= recno; --cnt) 195 WR(lines[cnt].l, lines[cnt].len); 196 } else { 197 if (wrap) 198 for (cnt = recno; cnt < off; ++cnt) 199 WR(lines[cnt].l, lines[cnt].len); 200 for (cnt = 0; cnt < recno; ++cnt) 201 WR(lines[cnt].l, lines[cnt].len); 202 } 203 } 204
Indexes created Tue Sep 23 14:10:03 GMT 2025