/*-
* 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.
*/
/* 1999-02-22 Arkadiusz Miśkiewicz <misiek@pld.ORG.PL>
* - added Native Language Support
*/
/*
* 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/mman.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <ctype.h>
#include <getopt.h>
#include "nls.h"
#include "xalloc.h"
#include "pathnames.h"
#include "closestream.h"
#define EQUAL 0
#define GREATER 1
#define LESS (-1)
static int dflag, fflag;
/* uglified the source a bit with globals, so that we only need
to allocate comparbuf once */
static int stringlen;
static char *string;
static char *comparbuf;
static char *binary_search (char *, char *);
static int compare (char *, char *);
static char *linear_search (char *, char *);
static int look (char *, char *);
static void print_from (char *, char *);
static void __attribute__((__noreturn__)) usage(void);
int
main(int argc, char *argv[])
{
struct stat sb;
int ch, fd, termchar;
char *back, *file, *front, *p;
static const struct option longopts[] = {
{"alternative", no_argument, NULL, 'a'},
{"alphanum", no_argument, NULL, 'd'},
{"ignore-case", no_argument, NULL, 'f'},
{"terminate", required_argument, NULL, 't'},
{"version", no_argument, NULL, 'V'},
{"help", no_argument, NULL, 'h'},
{NULL, 0, NULL, 0}
};
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
close_stdout_atexit();
setlocale(LC_ALL, "");
if ((file = getenv("WORDLIST")) && !access(file, R_OK))
/* use the WORDLIST */;
else
file = _PATH_WORDS;
termchar = '\0';
string = NULL; /* just for gcc */
while ((ch = getopt_long(argc, argv, "adft:Vh", longopts, NULL)) != -1)
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 'V':
print_version(EXIT_SUCCESS);
case 'h':
usage();
default:
errtryhelp(EXIT_FAILURE);
}
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:
warnx(_("bad usage"));
errtryhelp(EXIT_FAILURE);
}
if (termchar != '\0' && (p = strchr(string, termchar)) != NULL)
*++p = '\0';
if ((fd = open(file, O_RDONLY, 0)) < 0 || fstat(fd, &sb))
err(EXIT_FAILURE, "%s", file);
front = mmap(NULL, (size_t) sb.st_size, PROT_READ,
MAP_SHARED, fd, (off_t) 0);
if
#ifdef MAP_FAILED
(front == MAP_FAILED)
#else
((void *)(front) <= (void *)0)
#endif
err(EXIT_FAILURE, "%s", file);
back = front + sb.st_size;
return look(front, back);
}
static int
look(char *front, char *back)
{
int ch;
char *readp, *writep;
/* Reformat string to avoid doing it multiple times later. */
if (dflag) {
for (readp = writep = string; (ch = *readp++) != 0;) {
if (isalnum(ch) || isblank(ch))
*(writep++) = ch;
}
*writep = '\0';
stringlen = writep - string;
} else
stringlen = strlen(string);
comparbuf = xmalloc(stringlen+1);
front = binary_search(front, back);
front = linear_search(front, back);
if (front)
print_from(front, back);
free(comparbuf);
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.
*
* 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')
static char *
binary_search(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(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.
*/
static char *
linear_search(char *front, char *back)
{
while (front < back) {
switch (compare(front, back)) {
case EQUAL: /* Found it. */
return (front);
case LESS: /* No such string. */
return (NULL);
case GREATER: /* Keep going. */
break;
}
SKIP_PAST_NEWLINE(front, back);
}
return (NULL);
}
/*
* Print as many lines as match string, starting at front.
*/
static void
print_from(char *front, char *back)
{
int eol;
while (front < back && compare(front, back) == EQUAL) {
if (compare(front, back) == EQUAL) {
eol = 0;
while (front < back && !eol) {
if (putchar(*front) == EOF)
err(EXIT_FAILURE, "stdout");
if (*front++ == '\n')
eol = 1;
}
} else
SKIP_PAST_NEWLINE(front, back);
}
}
/*
* Return LESS, GREATER, or EQUAL depending on how string 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 "string" is null terminated. The string "s2" is '\n' terminated
* (or "s2end" terminated).
*
* We use strcasecmp etc, since it knows how to ignore case also
* in other locales.
*/
static int
compare(char *s2, char *s2end) {
int i;
char *p;
/* copy, ignoring things that should be ignored */
p = comparbuf;
i = stringlen;
while(s2 < s2end && *s2 != '\n' && i) {
if (!dflag || isalnum(*s2) || isblank(*s2))
{
*p++ = *s2;
i--;
}
s2++;
}
*p = 0;
/* and compare */
if (fflag)
i = strncasecmp(comparbuf, string, stringlen);
else
i = strncmp(comparbuf, string, stringlen);
return ((i > 0) ? LESS : (i < 0) ? GREATER : EQUAL);
}
static void __attribute__((__noreturn__)) usage(void)
{
FILE *out = stdout;
fputs(USAGE_HEADER, out);
fprintf(out, _(" %s [options] <string> [<file>...]\n"), program_invocation_short_name);
fputs(USAGE_SEPARATOR, out);
fputs(_("Display lines beginning with a specified string.\n"), out);
fputs(USAGE_OPTIONS, out);
fputs(_(" -a, --alternative use the alternative dictionary\n"), out);
fputs(_(" -d, --alphanum compare only blanks and alphanumeric characters\n"), out);
fputs(_(" -f, --ignore-case ignore case differences when comparing\n"), out);
fputs(_(" -t, --terminate <char> define the string-termination character\n"), out);
fputs(USAGE_SEPARATOR, out);
printf(USAGE_HELP_OPTIONS(26));
printf(USAGE_MAN_TAIL("look(1)"));
exit(EXIT_SUCCESS);
}
