1 files changed, 365 insertions, 0 deletions
diff --git a/misc-utils/look.c b/misc-utils/look.c
new file mode 100644
index 000000000..5a47970ed
--- /dev/null
+++ b/misc-utils/look.c
@@ -0,0 +1,365 @@
+/*-
+ * 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. 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.
+ */
+
+#ifndef lint
+static char copyright[] =
+"@(#) Copyright (c) 1991, 1993\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)look.c	8.1 (Berkeley) 6/14/93";
+#endif /* not lint */
+
+/*
+ * 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 <limits.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <getopt.h>
+#include "pathnames.h"
+
+/*
+ * FOLD and DICT convert characters to a normal form for comparison,
+ * according to the user specified flags.
+ * 
+ * DICT expects integers because it uses a non-character value to
+ * indicate a character which should not participate in comparisons.
+ */
+#define	EQUAL		0
+#define	GREATER		1
+#define	LESS		(-1)
+#define NO_COMPARE	(-2)
+
+#define	FOLD(c)	(isascii(c) && isupper(c) ? tolower(c) : (c))
+#define	DICT(c)	(isascii(c) && isalnum(c) ? (c) : NO_COMPARE)
+
+int dflag, fflag;
+
+char	*binary_search __P((char *, char *, char *));
+int	 compare __P((char *, char *, char *));
+void	 err __P((const char *fmt, ...));
+char	*linear_search __P((char *, char *, char *));
+int	 look __P((char *, char *, char *));
+void	 print_from __P((char *, char *, char *));
+
+static void usage __P((void));
+
+main(argc, argv)
+	int argc;
+	char *argv[];
+{
+	struct stat sb;
+	int ch, fd, termchar;
+	char *back, *file, *front, *string, *p;
+
+	file = _PATH_WORDS;
+	termchar = '\0';
+	while ((ch = getopt(argc, argv, "adft:")) != EOF)
+		switch(ch) {
+		case 'a':
+   		        file = _PATH_WORDS_ALT;
+		        break;
+		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("%s: %s", file, strerror(errno));
+	if ((void *)(front = mmap(NULL,
+				  (size_t)sb.st_size,
+				  PROT_READ,
+				  MAP_FILE|MAP_SHARED,
+				  fd,
+				  (off_t)0)) <= (void *)0)
+		err("%s: %s", file, strerror(errno));
+	back = front + sb.st_size;
+	exit(look(string, front, back));
+}
+
+look(string, front, back)
+	char *string, *front, *back;
+{
+	register int ch;
+	register char *readp, *writep;
+
+	/* Reformat string string to avoid doing it multiple times later. */
+	for (readp = writep = string; ch = *readp++;) {
+		if (fflag)
+			ch = FOLD(ch);
+		if (dflag)
+			ch = DICT(ch);
+		if (ch != NO_COMPARE)
+			*(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(string, front, back)
+	register char *string, *front, *back;
+{
+	register 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(string, front, back)
+	char *string, *front, *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(string, front, back)
+	register char *string, *front, *back;
+{
+	for (; front < back && compare(string, front, back) == EQUAL; ++front) {
+		for (; front < back && *front != '\n'; ++front)
+			if (putchar(*front) == EOF)
+				err("stdout: %s", strerror(errno));
+		if (putchar('\n') == EOF)
+			err("stdout: %s", strerror(errno));
+	}
+}
+
+/*
+ * 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(s1, s2, back)
+	register char *s1, *s2, *back;
+{
+	register int ch;
+
+	for (; *s1 && s2 < back && *s2 != '\n';) {
+		ch = *s2;
+		if (fflag)
+			ch = FOLD(ch);
+		if (dflag)
+			ch = DICT(ch);
+
+		if (ch == NO_COMPARE) {
+			++s2;		/* Ignore character in comparison. */
+			continue;
+		}
+		if (*s1 != ch)
+			return (*s1 < ch ? LESS : GREATER);
+		++s1;
+		++s2;
+	}
+	return (*s1 ? GREATER : EQUAL);
+}
+
+static void
+usage()
+{
+	(void)fprintf(stderr, "usage: look [-dfa] [-t char] string [file]\n");
+	exit(2);
+}
+
+#if __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+
+void
+#if __STDC__
+err(const char *fmt, ...)
+#else
+err(fmt, va_alist)
+	char *fmt;
+	va_dcl
+#endif
+{
+	va_list ap;
+#if __STDC__
+	va_start(ap, fmt);
+#else
+	va_start(ap);
+#endif
+	(void)fprintf(stderr, "look: ");
+	(void)vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	(void)fprintf(stderr, "\n");
+	exit(2);
+	/* NOTREACHED */
+}