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uniq.c revision 1.3 
      1 /*	$NetBSD: uniq.c,v 1.3 2007/06/24 19:51:43 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2007 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 #include <sys/cdefs.h>
     39 __RCSID("$NetBSD: uniq.c,v 1.3 2007/06/24 19:51:43 christos Exp $");
     40 
     41 #include <stdio.h>
     42 #include <string.h>
     43 #include <stdlib.h>
     44 #include <db.h>
     45 #include <err.h>
     46 #include <util.h>
     47 #include <ctype.h>
     48 #include <fcntl.h>
     49 
     50 extern const HASHINFO hinfo;
     51 
     52 void uniq(const char *);
     53 static int comp(const char *, char **, size_t *);
     54 
     55 /*
     56  * Preserve only unique content lines in a file. Input lines that have
     57  * content [alphanumeric characters before a comment] are white-space
     58  * normalized and have their comments removed. Then they are placed
     59  * in a hash table, and only the first instance of them is printed.
     60  * Comment lines without any alphanumeric content are always printed
     61  * since they are there to make the file "pretty". Comment lines with
     62  * alphanumeric content are also placed into the hash table and only
     63  * printed once.
     64  */
     65 void
     66 uniq(const char *fname)
     67 {
     68 	DB *db;
     69 	DBT key;
     70 	static const DBT data = { NULL, 0 };
     71 	FILE *fp;
     72 	char *line;
     73 	size_t len;
     74 
     75 	if ((db = dbopen(NULL, O_RDWR, 0, DB_HASH, &hinfo)) == NULL)
     76 		err(1, "Cannot create in memory database");
     77 
     78 	fp = efopen(fname, "r");
     79 	while ((line = fgetln(fp, &len)) != NULL) {
     80 		size_t complen = len;
     81 		char *compline;
     82 		if (!comp(line, &compline, &complen)) {
     83 			(void)fprintf(stdout, "%*.*s", (int)len, (int)len,
     84 			    line);
     85 			continue;
     86 		}
     87 		key.data = compline;
     88 		key.size = complen;
     89 		switch ((db->put)(db, &key, &data, R_NOOVERWRITE)) {
     90 		case 0:
     91 			(void)fprintf(stdout, "%*.*s", (int)len, (int)len,
     92 			    line);
     93 			break;
     94 		case 1:
     95 			break;
     96 		case -1:
     97 			err(1, "put");
     98 		default:
     99 			abort();
    100 			break;
    101 		}
    102 	}
    103 	(void)fflush(stdout);
    104 	exit(0);
    105 }
    106 
    107 /*
    108  * normalize whitespace in the original line and place a new string
    109  * with whitespace converted to a single space in compline. If the line
    110  * contains just comments, we preserve them. If it contains data and
    111  * comments, we kill the comments. Return 1 if the line had actual
    112  * contents, or 0 if it was just a comment without alphanumeric characters.
    113  */
    114 static int
    115 comp(const char *origline, char **compline, size_t *len)
    116 {
    117 	const unsigned char *p;
    118 	unsigned char *q;
    119 	char *cline;
    120 	size_t l = *len, complen;
    121 	int hasalnum, iscomment;
    122 
    123 	/* Eat leading space */
    124 	for (p = (const unsigned char *)origline; l && *p && isspace(*p);
    125 	    p++, l--)
    126 		continue;
    127 	cline = emalloc(l + 1);
    128 	(void)memcpy(cline, p, l);
    129 	cline[l] = '\0';
    130 	if (*cline == '\0')
    131 		return 0;
    132 
    133 	complen = 0;
    134 	hasalnum = 0;
    135 	iscomment = 0;
    136 
    137 	for (q = (unsigned char *)cline; l && *p; p++, l--) {
    138 		if (isspace(*p)) {
    139 			if (complen && isspace(q[-1]))
    140 				continue;
    141 			*q++ = ' ';
    142 			complen++;
    143 		} else {
    144 			if (!iscomment && *p == '#') {
    145 				if (hasalnum)
    146 					break;
    147 				iscomment = 1;
    148 			} else
    149 				hasalnum |= isalnum(*p);
    150 			*q++ = *p;
    151 			complen++;
    152 		}
    153 	}
    154 
    155 	/* Eat trailing space */
    156 	while (complen && isspace(q[-1])) {
    157 		--q;
    158 		--complen;
    159 	}
    160 	*q = '\0';
    161 	*compline = cline;
    162 	*len = complen;
    163 	return hasalnum;
    164 }
    165