/*      $NetBSD: uniq.c,v 1.7 2021/03/22 03:28:55 christos Exp $        */

/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: uniq.c,v 1.7 2021/03/22 03:28:55 christos Exp $");

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <db.h>
#include <err.h>
#include <util.h>
#include <ctype.h>
#include <fcntl.h>

#include "extern.h"

static const HASHINFO hinfo = {
       .bsize = 256,
       .ffactor = 4,
       .nelem = 32768,
       .cachesize = 1024,
       .hash = NULL,
       .lorder = 0
};

static int comp(const char *, char **, size_t *);

/*
* Preserve only unique content lines in a file. Input lines that have
* content [alphanumeric characters before a comment] are white-space
* normalized and have their comments removed. Then they are placed
* in a hash table, and only the first instance of them is printed.
* Comment lines without any alphanumeric content are always printed
* since they are there to make the file "pretty". Comment lines with
* alphanumeric content are also placed into the hash table and only
* printed once.
*/
void
uniq(const char *fname)
{
       DB *db;
       DBT key;
       static const DBT data = { NULL, 0 };
       FILE *fp;
       char *line;
       size_t len;

       if ((db = dbopen(NULL, O_RDWR, 0, DB_HASH, &hinfo)) == NULL)
               err(1, "Cannot create in memory database");

       fp = efopen(fname, "r");
       while ((line = fgetln(fp, &len)) != NULL) {
               size_t complen = len;
               char *compline;
               if (!comp(line, &compline, &complen)) {
                       (void)fprintf(stdout, "%*.*s", (int)len, (int)len,
                           line);
                       continue;
               }
               key.data = compline;
               key.size = complen;
               switch ((db->put)(db, &key, &data, R_NOOVERWRITE)) {
               case 0:
                       (void)fprintf(stdout, "%*.*s", (int)len, (int)len,
                           line);
                       break;
               case 1:
                       break;
               case -1:
                       err(1, "put");
                       /*NOTREACHED*/
               default:
                       abort();
                       break;
               }
       }
       (void)fflush(stdout);
       exit(0);
}

/*
* normalize whitespace in the original line and place a new string
* with whitespace converted to a single space in compline. If the line
* contains just comments, we preserve them. If it contains data and
* comments, we kill the comments. Return 1 if the line had actual
* contents, or 0 if it was just a comment without alphanumeric characters.
*/
static int
comp(const char *origline, char **compline, size_t *len)
{
       const unsigned char *p;
       unsigned char *q;
       char *cline;
       size_t l = *len, complen;
       int hasalnum, iscomment;

       /* Eat leading space */
       for (p = (const unsigned char *)origline; l && *p && isspace(*p);
           p++, l--)
               continue;
       if (*p == '\0' || l == 0)
               return 0;

       cline = emalloc(l + 1);
       (void)memcpy(cline, p, l);
       cline[l] = '\0';

       complen = 0;
       hasalnum = 0;
       iscomment = 0;

       for (q = (unsigned char *)cline; l && *p; p++, l--) {
               if (isspace(*p)) {
                       if (complen && isspace(q[-1]))
                               continue;
                       *q++ = ' ';
                       complen++;
               } else {
                       if (!iscomment && *p == '#') {
                               if (hasalnum)
                                       break;
                               iscomment = 1;
                       } else
                               hasalnum |= isalnum(*p);
                       *q++ = *p;
                       complen++;
               }
       }

       /* Eat trailing space */
       while (complen && isspace(q[-1])) {
               --q;
               --complen;
       }
       *q = '\0';
       if (!hasalnum) {
               free(cline);
               cline = NULL;
               complen = 0;
       }
       *compline = cline;
       *len = complen;
       return hasalnum;
}