1 /*- 2 * Copyright (c) 1991 The Regents of the University of California. 3 * 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 38 static char sccsid[] = "@(#)read.c 5.1 (Berkeley) 7/21/91"; 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 */ 61 void 62 bytes(fp, off) 63 register FILE *fp; 64 long 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("%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 84 if (rflag) { 85 for (t = p - 1, len = 0; t >= sp; --t, ++len) 86 if (*t == '\n' && len) { 87 WR(t + 1, len); 88 len = 0; 89 } 90 if (wrap) { 91 tlen = len; 92 for (t = ep - 1, len = 0; t >= p; --t, ++len) 93 if (*t == '\n') { 94 if (len) { 95 WR(t + 1, len); 96 len = 0; 97 } 98 if (tlen) { 99 WR(sp, tlen); 100 tlen = 0; 101 } 102 } 103 if (len) 104 WR(t + 1, len); 105 if (tlen) 106 WR(sp, tlen); 107 } 108 } else { 109 if (wrap && (len = ep - p)) 110 WR(p, len); 111 if (len = p - sp) 112 WR(sp, len); 113 } 114 } 115 116 /* 117 * lines -- read lines to an offset from the end and display. 118 * 119 * This is the function that reads to a line offset from the end of the input, 120 * storing the data in an array of buffers which is then displayed. If the 121 * rflag is set, the data is displayed in lines in reverse order, and this 122 * routine has the usual nastiness of trying to find the newlines. Otherwise, 123 * it is displayed from the line closest to the beginning of the input to 124 * the end. 125 */ 126 void 127 lines(fp, off) 128 register FILE *fp; 129 long off; 130 { 131 struct { 132 u_int blen; 133 u_int len; 134 char *l; 135 } *lines; 136 register int ch; 137 register char *p; 138 u_int blen, cnt, recno; 139 int wrap; 140 char *sp; 141 142 if ((lines = malloc(off * sizeof(*lines))) == NULL) 143 err("%s", strerror(errno)); 144 145 sp = NULL; 146 blen = cnt = recno = wrap = 0; 147 148 while ((ch = getc(fp)) != EOF) { 149 if (++cnt > blen) { 150 if ((sp = realloc(sp, blen += 1024)) == NULL) 151 err("%s", strerror(errno)); 152 p = sp + cnt - 1; 153 } 154 *p++ = ch; 155 if (ch == '\n') { 156 if (lines[recno].blen < cnt) { 157 lines[recno].blen = cnt + 256; 158 if ((lines[recno].l = realloc(lines[recno].l, 159 lines[recno].blen)) == NULL) 160 err("%s", strerror(errno)); 161 } 162 bcopy(sp, lines[recno].l, lines[recno].len = cnt); 163 cnt = 0; 164 p = sp; 165 if (++recno == off) { 166 wrap = 1; 167 recno = 0; 168 } 169 } 170 } 171 if (ferror(fp)) 172 ierr(); 173 if (cnt) { 174 lines[recno].l = sp; 175 lines[recno].len = cnt; 176 if (++recno == off) { 177 wrap = 1; 178 recno = 0; 179 } 180 } 181 182 if (rflag) { 183 for (cnt = recno - 1; cnt >= 0; --cnt) 184 WR(lines[cnt].l, lines[cnt].len); 185 if (wrap) 186 for (cnt = off - 1; cnt >= recno; --cnt) 187 WR(lines[cnt].l, lines[cnt].len); 188 } else { 189 if (wrap) 190 for (cnt = recno; cnt < off; ++cnt) 191 WR(lines[cnt].l, lines[cnt].len); 192 for (cnt = 0; cnt < recno; ++cnt) 193 WR(lines[cnt].l, lines[cnt].len); 194 } 195 } 196