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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/types.h> 34 #include <sys/stat.h> 35 36 #include <err.h> 37 #include <errno.h> 38 #include <fcntl.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <strings.h> 43 #include <unistd.h> 44 45 #include "extern.h" 46 47 /* 48 * bytes -- read bytes to an offset from the end and display. 49 * 50 * This is the function that reads to a byte offset from the end of the input, 51 * storing the data in a wrap-around buffer which is then displayed. If the 52 * rflag is set, the data is displayed in lines in reverse order, and this 53 * routine has the usual nastiness of trying to find the newlines. Otherwise, 54 * it is displayed from the character closest to the beginning of the input to 55 * the end. 56 */ 57 int 58 bytes(FILE *fp, const char *fn, off_t off) 59 { 60 int ch, len, tlen; 61 char *ep, *p, *t; 62 int wrap; 63 char *sp; 64 65 if ((sp = p = malloc(off)) == NULL) 66 err(1, "malloc"); 67 68 for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF; ) { 69 *p = ch; 70 if (++p == ep) { 71 wrap = 1; 72 p = sp; 73 } 74 } 75 if (ferror(fp)) { 76 ierr(fn); 77 free(sp); 78 return (1); 79 } 80 81 if (rflag) { 82 for (t = p - 1, len = 0; t >= sp; --t, ++len) 83 if (*t == '\n' && len) { 84 WR(t + 1, len); 85 len = 0; 86 } 87 if (wrap) { 88 tlen = len; 89 for (t = ep - 1, len = 0; t >= p; --t, ++len) 90 if (*t == '\n') { 91 if (len) { 92 WR(t + 1, len); 93 len = 0; 94 } 95 if (tlen) { 96 WR(sp, tlen); 97 tlen = 0; 98 } 99 } 100 if (len) 101 WR(t + 1, len); 102 if (tlen) 103 WR(sp, tlen); 104 } 105 } else { 106 if (wrap && (len = ep - p)) 107 WR(p, len); 108 len = p - sp; 109 if (len) 110 WR(sp, len); 111 } 112 113 free(sp); 114 return (0); 115 } 116 117 /* 118 * lines -- read lines to an offset from the end and display. 119 * 120 * This is the function that reads to a line offset from the end of the input, 121 * storing the data in an array of buffers which is then displayed. If the 122 * rflag is set, the data is displayed in lines in reverse order, and this 123 * routine has the usual nastiness of trying to find the newlines. Otherwise, 124 * it is displayed from the line closest to the beginning of the input to 125 * the end. 126 */ 127 int 128 lines(FILE *fp, const char *fn, off_t off) 129 { 130 struct { 131 int blen; 132 uint_t len; 133 char *l; 134 } *llines; 135 int ch, rc; 136 char *p, *sp; 137 int blen, cnt, recno, wrap; 138 139 if ((llines = malloc(off * sizeof (*llines))) == NULL) 140 err(1, "malloc"); 141 bzero(llines, off * sizeof (*llines)); 142 p = sp = NULL; 143 blen = cnt = recno = wrap = 0; 144 rc = 0; 145 146 while ((ch = getc(fp)) != EOF) { 147 if (++cnt > blen) { 148 if ((sp = realloc(sp, blen += 1024)) == NULL) 149 err(1, "realloc"); 150 p = sp + cnt - 1; 151 } 152 *p++ = ch; 153 if (ch == '\n') { 154 if ((int)llines[recno].blen < cnt) { 155 llines[recno].blen = cnt + 256; 156 if ((llines[recno].l = realloc(llines[recno].l, 157 llines[recno].blen)) == NULL) 158 err(1, "realloc"); 159 } 160 bcopy(sp, llines[recno].l, llines[recno].len = cnt); 161 cnt = 0; 162 p = sp; 163 if (++recno == off) { 164 wrap = 1; 165 recno = 0; 166 } 167 } 168 } 169 if (ferror(fp)) { 170 ierr(fn); 171 rc = 1; 172 goto done; 173 } 174 if (cnt) { 175 llines[recno].l = sp; 176 sp = NULL; 177 llines[recno].len = cnt; 178 if (++recno == off) { 179 wrap = 1; 180 recno = 0; 181 } 182 } 183 184 if (rflag) { 185 for (cnt = recno - 1; cnt >= 0; --cnt) 186 WR(llines[cnt].l, llines[cnt].len); 187 if (wrap) 188 for (cnt = off - 1; cnt >= recno; --cnt) 189 WR(llines[cnt].l, llines[cnt].len); 190 } else { 191 if (wrap) 192 for (cnt = recno; cnt < off; ++cnt) 193 WR(llines[cnt].l, llines[cnt].len); 194 for (cnt = 0; cnt < recno; ++cnt) 195 WR(llines[cnt].l, llines[cnt].len); 196 } 197 done: 198 for (cnt = 0; cnt < off; cnt++) 199 free(llines[cnt].l); 200 free(sp); 201 free(llines); 202 return (rc); 203 } 204