2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * David Hitz of Auspex Systems, Inc.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
34 static const char copyright[] =
35 "@(#) Copyright (c) 1991, 1993\n\
36 The Regents of the University of California. All rights reserved.\n";
41 static char sccsid[] = "@(#)look.c 8.2 (Berkeley) 5/4/95";
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
48 * look -- find lines in a sorted list.
50 * The man page said that TABs and SPACEs participate in -d comparisons.
51 * In fact, they were ignored. This implements historic practice, not
55 #include <sys/types.h>
73 #include "pathnames.h"
75 static char _path_words[] = _PATH_WORDS;
81 static int dflag, fflag;
83 static char *binary_search(wchar_t *, unsigned char *, unsigned char *);
84 static int compare(wchar_t *, unsigned char *, unsigned char *);
85 static char *linear_search(wchar_t *, unsigned char *, unsigned char *);
86 static int look(wchar_t *, unsigned char *, unsigned char *);
87 static wchar_t *prepkey(const char *, wchar_t);
88 static void print_from(wchar_t *, unsigned char *, unsigned char *);
90 static void usage(void);
92 static struct option longopts[] = {
93 { "alternative",no_argument, NULL, 'a' },
94 { "alphanum", no_argument, NULL, 'd' },
95 { "ignore-case",no_argument, NULL, 'i' },
96 { "terminate", required_argument, NULL, 't'},
101 main(int argc, char *argv[])
106 unsigned char *back, *front;
107 unsigned const char *file;
110 (void) setlocale(LC_CTYPE, "");
114 while ((ch = getopt_long(argc, argv, "+adft:", longopts, NULL)) != -1)
126 if (mbrtowc(&termchar, optarg, MB_LEN_MAX, NULL) !=
128 errx(2, "invalid termination character");
139 if (argc == 1) /* But set -df by default. */
141 key = prepkey(*argv++, termchar);
148 if ((fd = open(file, O_RDONLY, 0)) < 0 || fstat(fd, &sb))
150 if ((uintmax_t)sb.st_size > (uintmax_t)SIZE_T_MAX)
151 errx(2, "%s: %s", file, strerror(EFBIG));
152 if (sb.st_size == 0) {
156 if ((front = mmap(NULL, (size_t)sb.st_size, PROT_READ, MAP_SHARED, fd, (off_t)0)) == MAP_FAILED)
158 back = front + sb.st_size;
159 match *= (look(key, front, back));
161 } while (argc-- > 2 && (file = *argv++));
167 prepkey(const char *string, wchar_t termchar)
170 wchar_t *key, *writep;
175 * Reformat search string and convert to wide character representation
176 * to avoid doing it multiple times later.
178 if ((key = malloc(sizeof(wchar_t) * (strlen(string) + 1))) == NULL)
182 while ((clen = mbrtowc(&ch, readp, MB_LEN_MAX, NULL)) != 0) {
183 if (clen == (size_t)-1 || clen == (size_t)-2)
184 errc(2, EILSEQ, NULL);
187 if (!dflag || iswalnum(ch))
192 if (termchar != L'\0' && (writep = wcschr(key, termchar)) != NULL)
198 look(wchar_t *string, unsigned char *front, unsigned char *back)
201 front = binary_search(string, front, back);
202 front = linear_search(string, front, back);
205 print_from(string, front, back);
206 return (front ? 0 : 1);
211 * Binary search for "string" in memory between "front" and "back".
213 * This routine is expected to return a pointer to the start of a line at
214 * *or before* the first word matching "string". Relaxing the constraint
215 * this way simplifies the algorithm.
218 * front points to the beginning of a line at or before the first
221 * back points to the beginning of a line at or after the first
224 * Base of the Invariants.
228 * Advancing the Invariants:
230 * p = first newline after halfway point from front to back.
232 * If the string at "p" is not greater than the string to match,
233 * p is the new front. Otherwise it is the new back.
237 * The definition of the routine allows it return at any point,
238 * since front is always at or before the line to print.
240 * In fact, it returns when the chosen "p" equals "back". This
241 * implies that there exists a string is least half as long as
242 * (back - front), which in turn implies that a linear search will
243 * be no more expensive than the cost of simply printing a string or two.
245 * Trying to continue with binary search at this point would be
246 * more trouble than it's worth.
248 #define SKIP_PAST_NEWLINE(p, back) \
249 while (p < back && *p++ != '\n');
252 binary_search(wchar_t *string, unsigned char *front, unsigned char *back)
256 p = front + (back - front) / 2;
257 SKIP_PAST_NEWLINE(p, back);
260 * If the file changes underneath us, make sure we don't
263 while (p < back && back > front) {
264 if (compare(string, p, back) == GREATER)
268 p = front + (back - front) / 2;
269 SKIP_PAST_NEWLINE(p, back);
275 * Find the first line that starts with string, linearly searching from front
278 * Return NULL for no such line.
280 * This routine assumes:
282 * o front points at the first character in a line.
283 * o front is before or at the first line to be printed.
286 linear_search(wchar_t *string, unsigned char *front, unsigned char *back)
288 while (front < back) {
289 switch (compare(string, front, back)) {
290 case EQUAL: /* Found it. */
292 case LESS: /* No such string. */
294 case GREATER: /* Keep going. */
297 SKIP_PAST_NEWLINE(front, back);
303 * Print as many lines as match string, starting at front.
306 print_from(wchar_t *string, unsigned char *front, unsigned char *back)
308 for (; front < back && compare(string, front, back) == EQUAL; ++front) {
309 for (; front < back && *front != '\n'; ++front)
310 if (putchar(*front) == EOF)
312 if (putchar('\n') == EOF)
318 * Return LESS, GREATER, or EQUAL depending on how the string1 compares with
319 * string2 (s1 ??? s2).
321 * o Matches up to len(s1) are EQUAL.
322 * o Matches up to len(s2) are GREATER.
324 * Compare understands about the -f and -d flags, and treats comparisons
327 * The string "s1" is null terminated. The string s2 is '\n' terminated (or
328 * "back" terminated).
331 compare(wchar_t *s1, unsigned char *s2, unsigned char *back)
336 for (; *s1 && s2 < back && *s2 != '\n'; ++s1, s2 += len2) {
338 len2 = mbrtowc(&ch2, s2, back - s2, NULL);
339 if (len2 == (size_t)-1 || len2 == (size_t)-2) {
345 if (dflag && !iswalnum(ch2)) {
346 /* Ignore character in comparison. */
351 return (ch1 < ch2 ? LESS : GREATER);
353 return (*s1 ? GREATER : EQUAL);
359 (void)fprintf(stderr, "usage: look [-df] [-t char] string [file ...]\n");