Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.bin/look/look.c	Lines:	0	75	0.0 %
Date:	2017-11-13	Branches:	0	86	0.0 %


/*	$OpenBSD: look.c,v 1.21 2017/01/21 10:03:27 krw Exp $	*/
/*	$NetBSD: look.c,v 1.7 1995/08/31 22:41:02 jtc Exp $	*/

/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * David Hitz of Auspex Systems, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * look -- find lines in a sorted list.
 *
 * The man page said that TABs and SPACEs participate in -d comparisons.
 * In fact, they were ignored.  This implements historic practice, not
 * the manual page.
 */

#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <err.h>

#include "pathnames.h"

#define	EQUAL		0
#define	GREATER		1
#define	LESS		(-1)

int dflag, fflag;

char	*binary_search(char *, char *, char *);
int	 compare(char *, char *, char *);
char	*linear_search(char *, char *, char *);
int	 look(char *, char *, char *);
void	 print_from(char *, char *, char *);
void	 usage(void);

int
main(int argc, char *argv[])
{
	struct stat sb;
	int ch, fd, termchar;
	char *back, *file, *front, *string, *p;

	if (pledge("stdio rpath flock cpath wpath", NULL) == -1)
		err(1, "pledge");

	file = _PATH_WORDS;
	termchar = '\0';
	while ((ch = getopt(argc, argv, "dft:")) != -1)
		switch(ch) {
		case 'd':
			dflag = 1;
			break;
		case 'f':
			fflag = 1;
			break;
		case 't':
			termchar = *optarg;
			break;
		case '?':
		default:
			usage();
		}
	argc -= optind;
	argv += optind;

	switch (argc) {
	case 2:				/* Don't set -df for user. */
		string = *argv++;
		file = *argv;
		break;
	case 1:				/* But set -df by default. */
		dflag = fflag = 1;
		string = *argv;
		break;
	default:
		usage();
	}

	if (termchar != '\0' && (p = strchr(string, termchar)) != NULL)
		*++p = '\0';

	if ((fd = open(file, O_RDONLY, 0)) < 0 || fstat(fd, &sb))
		err(2, "%s", file);
	if (sb.st_size > SIZE_MAX)
		errc(2, EFBIG, "%s", file);
	if ((front = mmap(NULL,
	    (size_t)sb.st_size, PROT_READ, MAP_PRIVATE, fd, (off_t)0)) == MAP_FAILED)
		err(2, "%s", file);
	back = front + sb.st_size;
	exit(look(string, front, back));
}

int
look(char *string, char *front, char *back)
{
	int ch;
	char *readp, *writep;

	/* Reformat string to avoid doing it multiple times later. */
	for (readp = writep = string; (ch = *readp++);) {
		if (fflag)
			ch = tolower((unsigned char)ch);
		if (!dflag || isalnum((unsigned char)ch))
			*(writep++) = ch;
	}
	*writep = '\0';

	front = binary_search(string, front, back);
	front = linear_search(string, front, back);

	if (front)
		print_from(string, front, back);
	return (front ? 0 : 1);
}


/*
 * Binary search for "string" in memory between "front" and "back".
 *
 * This routine is expected to return a pointer to the start of a line at
 * *or before* the first word matching "string".  Relaxing the constraint
 * this way simplifies the algorithm.
 *
 * Invariants:
 *	front points to the beginning of a line at or before the first
 *	matching string.
 *
 *	back points to the beginning of a line at or after the first
 *	matching line.
 *
 * Base of the Invariants.
 *	front = NULL;
 *	back = EOF;
 *
 * Advancing the Invariants:
 *
 *	p = first newline after halfway point from front to back.
 *
 *	If the string at "p" is not greater than the string to match,
 *	p is the new front.  Otherwise it is the new back.
 *
 * Termination:
 *
 *	The definition of the routine allows it return at any point,
 *	since front is always at or before the line to print.
 *
 *	In fact, it returns when the chosen "p" equals "back".  This
 *	implies that there exists a string is least half as long as
 *	(back - front), which in turn implies that a linear search will
 *	be no more expensive than the cost of simply printing a string or two.
 *
 *	Trying to continue with binary search at this point would be
 *	more trouble than it's worth.
 */
#define	SKIP_PAST_NEWLINE(p, back) \
	while (p < back && *p++ != '\n');

char *
binary_search(char *string, char *front, char *back)
{
	char *p;

	p = front + (back - front) / 2;
	SKIP_PAST_NEWLINE(p, back);

	/*
	 * If the file changes underneath us, make sure we don't
	 * infinitely loop.
	 */
	while (p < back && back > front) {
		if (compare(string, p, back) == GREATER)
			front = p;
		else
			back = p;
		p = front + (back - front) / 2;
		SKIP_PAST_NEWLINE(p, back);
	}
	return (front);
}

/*
 * Find the first line that starts with string, linearly searching from front
 * to back.
 *
 * Return NULL for no such line.
 *
 * This routine assumes:
 *
 *	o front points at the first character in a line.
 *	o front is before or at the first line to be printed.
 */
char *
linear_search(char *string, char *front, char *back)
{
	while (front < back) {
		switch (compare(string, front, back)) {
		case EQUAL:		/* Found it. */
			return (front);
			break;
		case LESS:		/* No such string. */
			return (NULL);
			break;
		case GREATER:		/* Keep going. */
			break;
		}
		SKIP_PAST_NEWLINE(front, back);
	}
	return (NULL);
}

/*
 * Print as many lines as match string, starting at front.
 */
void
print_from(char *string, char *front, char *back)
{
	for (; front < back && compare(string, front, back) == EQUAL; ++front) {
		for (; front < back && *front != '\n'; ++front)
			if (putchar(*front) == EOF)
				err(2, "stdout");
		if (putchar('\n') == EOF)
			err(2, "stdout");
	}
}

/*
 * Return LESS, GREATER, or EQUAL depending on how the string1 compares with
 * string2 (s1 ??? s2).
 *
 *	o Matches up to len(s1) are EQUAL.
 *	o Matches up to len(s2) are GREATER.
 *
 * Compare understands about the -f and -d flags, and treats comparisons
 * appropriately.
 *
 * The string "s1" is null terminated.  The string s2 is '\n' terminated (or
 * "back" terminated).
 */
int
compare(char *s1, char *s2, char *back)
{
	int ch;

	for (; *s1 && s2 < back && *s2 != '\n'; ++s1, ++s2) {
		ch = *s2;
		if (fflag)
			ch = tolower((unsigned char)ch);
		if (dflag && !isalnum((unsigned char)ch)) {
			++s2;		/* Ignore character in comparison. */
			continue;
		}
		if (*s1 != ch)
			return (*s1 < ch ? LESS : GREATER);
	}
	return (*s1 ? GREATER : EQUAL);
}

void
usage(void)
{
	(void)fprintf(stderr,
	    "usage: look [-df] [-t termchar] string [file]\n");
	exit(2);
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: look.c,v 1.21 2017/01/21 10:03:27 krw Exp $ */
2			/* $NetBSD: look.c,v 1.7 1995/08/31 22:41:02 jtc Exp $ */
3
4			/*-
5			* Copyright (c) 1991, 1993
6			* The Regents of the University of California. All rights reserved.
7			*
8			* This code is derived from software contributed to Berkeley by
9			* David Hitz of Auspex Systems, Inc.
10			*
11			* Redistribution and use in source and binary forms, with or without
12			* modification, are permitted provided that the following conditions
13			* are met:
14			* 1. Redistributions of source code must retain the above copyright
15			* notice, this list of conditions and the following disclaimer.
16			* 2. Redistributions in binary form must reproduce the above copyright
17			* notice, this list of conditions and the following disclaimer in the
18			* documentation and/or other materials provided with the distribution.
19			* 3. Neither the name of the University nor the names of its contributors
20			* may be used to endorse or promote products derived from this software
21			* without specific prior written permission.
22			*
23			* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26			* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33			* SUCH DAMAGE.
34			*/
35
36			/*
37			* look -- find lines in a sorted list.
38			*
39			* The man page said that TABs and SPACEs participate in -d comparisons.
40			* In fact, they were ignored. This implements historic practice, not
41			* the manual page.
42			*/
43
44			#include <sys/types.h>
45			#include <sys/mman.h>
46			#include <sys/stat.h>
47
48			#include <ctype.h>
49			#include <errno.h>
50			#include <fcntl.h>
51			#include <stdint.h>
52			#include <stdio.h>
53			#include <stdlib.h>
54			#include <string.h>
55			#include <unistd.h>
56			#include <err.h>
57
58			#include "pathnames.h"
59
60			#define EQUAL 0
61			#define GREATER 1
62			#define LESS (-1)
63
64			int dflag, fflag;
65
66			char binary_search(char , char , char );
67			int compare(char , char , char *);
68			char linear_search(char , char , char );
69			int look(char , char , char *);
70			void print_from(char , char , char *);
71			void usage(void);
72
73			int
74			main(int argc, char *argv[])
75			{
76			struct stat sb;
77			int ch, fd, termchar;
78			char back, file, front, string, *p;
79
80			if (pledge("stdio rpath flock cpath wpath", NULL) == -1)
81			err(1, "pledge");
82
83			file = _PATH_WORDS;
84			termchar = '\0';
85			while ((ch = getopt(argc, argv, "dft:")) != -1)
86			switch(ch) {
87			case 'd':
88			dflag = 1;
89			break;
90			case 'f':
91			fflag = 1;
92			break;
93			case 't':
94			termchar = *optarg;
95			break;
96			case '?':
97			default:
98			usage();
99			}
100			argc -= optind;
101			argv += optind;
102
103			switch (argc) {
104			case 2: /* Don't set -df for user. */
105			string = *argv++;
106			file = *argv;
107			break;
108			case 1: /* But set -df by default. */
109			dflag = fflag = 1;
110			string = *argv;
111			break;
112			default:
113			usage();
114			}
115
116			if (termchar != '\0' && (p = strchr(string, termchar)) != NULL)
117			*++p = '\0';
118
119			if ((fd = open(file, O_RDONLY, 0)) < 0 \|\| fstat(fd, &sb))
120			err(2, "%s", file);
121			if (sb.st_size > SIZE_MAX)
122			errc(2, EFBIG, "%s", file);
123			if ((front = mmap(NULL,
124			(size_t)sb.st_size, PROT_READ, MAP_PRIVATE, fd, (off_t)0)) == MAP_FAILED)
125			err(2, "%s", file);
126			back = front + sb.st_size;
127			exit(look(string, front, back));
128			}
129
130			int
131			look(char string, char front, char *back)
132			{
133			int ch;
134			char readp, writep;
135
136			/* Reformat string to avoid doing it multiple times later. */
137			for (readp = writep = string; (ch = *readp++);) {
138			if (fflag)
139			ch = tolower((unsigned char)ch);
140			if (!dflag \|\| isalnum((unsigned char)ch))
141			*(writep++) = ch;
142			}
143			*writep = '\0';
144
145			front = binary_search(string, front, back);
146			front = linear_search(string, front, back);
147
148			if (front)
149			print_from(string, front, back);
150			return (front ? 0 : 1);
151			}
152
153
154			/*
155			* Binary search for "string" in memory between "front" and "back".
156			*
157			* This routine is expected to return a pointer to the start of a line at
158			* or before the first word matching "string". Relaxing the constraint
159			* this way simplifies the algorithm.
160			*
161			* Invariants:
162			* front points to the beginning of a line at or before the first
163			* matching string.
164			*
165			* back points to the beginning of a line at or after the first
166			* matching line.
167			*
168			* Base of the Invariants.
169			* front = NULL;
170			* back = EOF;
171			*
172			* Advancing the Invariants:
173			*
174			* p = first newline after halfway point from front to back.
175			*
176			* If the string at "p" is not greater than the string to match,
177			* p is the new front. Otherwise it is the new back.
178			*
179			* Termination:
180			*
181			* The definition of the routine allows it return at any point,
182			* since front is always at or before the line to print.
183			*
184			* In fact, it returns when the chosen "p" equals "back". This
185			* implies that there exists a string is least half as long as
186			* (back - front), which in turn implies that a linear search will
187			* be no more expensive than the cost of simply printing a string or two.
188			*
189			* Trying to continue with binary search at this point would be
190			* more trouble than it's worth.
191			*/
192			#define SKIP_PAST_NEWLINE(p, back) \
193			while (p < back && *p++ != '\n');
194
195			char *
196			binary_search(char string, char front, char *back)
197			{
198			char *p;
199
200			p = front + (back - front) / 2;
201			SKIP_PAST_NEWLINE(p, back);
202
203			/*
204			* If the file changes underneath us, make sure we don't
205			* infinitely loop.
206			*/
207			while (p < back && back > front) {
208			if (compare(string, p, back) == GREATER)
209			front = p;
210			else
211			back = p;
212			p = front + (back - front) / 2;
213			SKIP_PAST_NEWLINE(p, back);
214			}
215			return (front);
216			}
217
218			/*
219			* Find the first line that starts with string, linearly searching from front
220			* to back.
221			*
222			* Return NULL for no such line.
223			*
224			* This routine assumes:
225			*
226			* o front points at the first character in a line.
227			* o front is before or at the first line to be printed.
228			*/
229			char *
230			linear_search(char string, char front, char *back)
231			{
232			while (front < back) {
233			switch (compare(string, front, back)) {
234			case EQUAL: /* Found it. */
235			return (front);
236			break;
237			case LESS: /* No such string. */
238			return (NULL);
239			break;
240			case GREATER: /* Keep going. */
241			break;
242			}
243			SKIP_PAST_NEWLINE(front, back);
244			}
245			return (NULL);
246			}
247
248			/*
249			* Print as many lines as match string, starting at front.
250			*/
251			void
252			print_from(char string, char front, char *back)
253			{
254			for (; front < back && compare(string, front, back) == EQUAL; ++front) {
255			for (; front < back && *front != '\n'; ++front)
256			if (putchar(*front) == EOF)
257			err(2, "stdout");
258			if (putchar('\n') == EOF)
259			err(2, "stdout");
260			}
261			}
262
263			/*
264			* Return LESS, GREATER, or EQUAL depending on how the string1 compares with
265			* string2 (s1 ??? s2).
266			*
267			* o Matches up to len(s1) are EQUAL.
268			* o Matches up to len(s2) are GREATER.
269			*
270			* Compare understands about the -f and -d flags, and treats comparisons
271			* appropriately.
272			*
273			* The string "s1" is null terminated. The string s2 is '\n' terminated (or
274			* "back" terminated).
275			*/
276			int
277			compare(char s1, char s2, char *back)
278			{
279			int ch;
280
281			for (; s1 && s2 < back && s2 != '\n'; ++s1, ++s2) {
282			ch = *s2;
283			if (fflag)
284			ch = tolower((unsigned char)ch);
285			if (dflag && !isalnum((unsigned char)ch)) {
286			++s2; /* Ignore character in comparison. */
287			continue;
288			}
289			if (*s1 != ch)
290			return (*s1 < ch ? LESS : GREATER);
291			}
292			return (*s1 ? GREATER : EQUAL);
293			}
294
295			void
296			usage(void)
297			{
298			(void)fprintf(stderr,
299			"usage: look [-df] [-t termchar] string [file]\n");
300			exit(2);
301			}