d5d093bd10
Obtained from: https://web.archive.org/web/20090620082249/http://worldserver.oleane.com/rsn/ascd-en.html
386 lines
8.1 KiB
C
386 lines
8.1 KiB
C
/*
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* $Id: index.c,v 1.2 1999/02/14 09:50:42 dirk Exp $
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*
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* This file is part of WorkMan, the civilized CD player library
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* (c) 1991-1997 by Steven Grimm (original author)
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* (c) by Dirk Försterling (current 'author' = maintainer)
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* The maintainer can be contacted by his e-mail address:
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* milliByte@DeathsDoor.com
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the Free
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*
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* Maintain an external index file for a WorkMan CD database.
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* Uses the Berkeley libdb library, available from ftp.cs.berkeley.edu.
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*/
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static char index_id[] = "$Id: index.c,v 1.2 1999/02/14 09:50:42 dirk Exp $";
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#ifdef LIBDB
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#include <stdio.h>
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#include <stdlib.h>
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#include <db.h>
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#include <fcntl.h>
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#include <string.h>
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#include <netinet/in.h> /* for htonl() */
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#include "include/wm_config.h"
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#include "include/wm_index.h"
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extern int suppress_locking;
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/*
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* idx_find_entry()
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*
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* Find an entry in the index file.
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*
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* Input:
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* file Name of database file (text version).
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* ntracks Number of tracks on the CD we're looking for.
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* tracks Array of track start times.
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* len CD length in frames.
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* fuzz Fuzz factor (tolerance value).
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* pos Pointer to return value.
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*
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* Output:
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* 1 No matching record found.
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* 0 Record found; *pos contains offset into text file.
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* -1 Index file out of date or inaccessible, or another error.
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*/
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int
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idx_find_entry( char *file, int ntracks, int *tracks,
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int len, int fuzz, unsigned long *pos )
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{
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unsigned long dbpos;
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char *indexname = NULL, keyval[8];
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int c;
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FILE *text;
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DB *index;
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DBT key, data;
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BTREEINFO bti;
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/*
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* First, see if the text file is accessible. Lock it if so.
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*/
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text = fopen(file, "r");
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if (text == NULL)
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return (-1);
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if ((c = getc(text)) == EOF)
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{
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fclose(text);
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return (-1);
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}
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if (! suppress_locking)
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if (lockit(fileno(text), F_RDLCK))
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{
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fclose(text);
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return (-1);
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}
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/*
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* Open the index file.
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*/
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indexname = malloc(strlen(file) + sizeof(".ind"));
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if (indexname == NULL)
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{
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fclose(text);
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return (-1);
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}
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strcpy(indexname, file);
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strcat(indexname, ".ind");
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bti.flags = 0;
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bti.cachesize = 0;
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bti.minkeypage = bti.maxkeypage = 0;
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bti.psize = bti.lorder = 0;
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bti.compare = NULL;
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bti.prefix = NULL;
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index = dbopen(indexname, O_RDONLY, 0666, DB_BTREE, &bti);
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free(indexname);
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if (index == NULL)
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{
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fclose(text);
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return (-1);
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}
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/*
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* Search for the first matching entry.
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*/
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sprintf(keyval, "%07d", tracks[ntracks - 1] - fuzz);
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key.data = keyval;
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key.size = 7;
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if (c = (index->seq)(index, &key, &data, R_CURSOR))
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{
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(index->close)(index);
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fclose(text);
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return (c);
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}
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/*
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* Now loop through all the possible matches, collecting them into
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* memory.
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*/
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do {
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char tracksline[750], *s;
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int i, val;
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/* Hit the end of the valid entries? */
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sscanf(key.data, "%d", &val);
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if (val > tracks[ntracks - 1] + fuzz)
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break;
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dbpos = ntohl(*((unsigned long *) data.data));
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if (fseek(text, dbpos, 0))
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break;
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fgets(tracksline, sizeof(tracksline), text);
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if (strncmp(tracksline, "tracks ", 7))
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break;
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(void) strtok(tracksline, " \t");
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/* Got a valid tracks line. See if it matches the CD. */
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s = strtok(NULL, " \t");
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if (s == NULL)
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break;
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if (atoi(s) != ntracks)
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continue;
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for (i = 0; i < ntracks; i++)
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{
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s = strtok(NULL, " \t");
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if (s == NULL)
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break;
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val = atoi(s);
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if (val + fuzz < tracks[i] || val - fuzz > tracks[i])
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break;
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}
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if (i != ntracks)
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continue;
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s = strtok(NULL, " \t");
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if (s == NULL)
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continue;
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val = atoi(s);
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if (val + fuzz / 75 < len / 75 || val + fuzz / 75 > len / 75)
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continue;
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/* XXX - add to sorted list! */
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*pos = dbpos;
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(index->close)(index);
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fclose(text);
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return (0);
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} while ((c = (index->seq)(index, &key, &data, R_NEXT)) == 0);
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if (c == 0)
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{
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/* An error. */
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(index->close)(index);
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fclose(text);
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return (-1);
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}
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(index->close)(index);
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fclose(text);
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return (1);
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}
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/*
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* idx_delete_entry()
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*
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* Delete an entry from the index file.
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*
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* Input:
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* file Name of database file (text version).
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* track Last track's start time (database key).
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* fuzz Fuzz factor (tolerance value).
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* pos Position of CD in database file.
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*
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* Output:
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* 1 No matching record found.
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* 0 Record deleted.
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* -1 Index file out of date or inaccessible, or another error.
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*
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* Note: it is the caller's responsibility to do locking, as it's assumed
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* that this operation will accompany a modification of the main database
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* file and will need to be atomic with that modification.
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*/
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int
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idx_delete_entry(char *file, int track, int fuzz, unsigned long pos )
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{
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unsigned long dbpos;
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char *indexname = NULL, keyval[8];
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int c, status;
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DB *index;
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DBT key, data;
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BTREEINFO bti;
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/*
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* Open the index file.
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*/
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indexname = malloc(strlen(file) + sizeof(".ind"));
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if (indexname == NULL)
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return (-1);
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strcpy(indexname, file);
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strcat(indexname, ".ind");
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bti.flags = 0;
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bti.cachesize = 0;
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bti.minkeypage = bti.maxkeypage = 0;
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bti.psize = bti.lorder = 0;
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bti.compare = NULL;
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bti.prefix = NULL;
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index = dbopen(indexname, O_RDWR, 0666, DB_BTREE, &bti);
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free(indexname);
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if (index == NULL)
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return (-1);
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/*
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* Search for the first matching entry.
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*/
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sprintf(keyval, "%07d", track - fuzz);
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key.data = keyval;
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key.size = 7;
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if (c = (index->seq)(index, &key, &data, R_CURSOR))
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{
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/*
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* Nothing matched!
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*/
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(index->close)(index);
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return (c);
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}
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/*
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* Look for the entry the user wants to delete.
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*/
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do {
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int val;
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/* Hit the end of the valid entries? */
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sscanf(key.data, "%d", &val);
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if (val > track + fuzz)
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break;
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/* Is this the entry we want? */
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if (pos == ntohl(*((unsigned long *) data.data)))
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{
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/*
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* Yep! Delete it.
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*/
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status = (index->del)(index, &key, R_CURSOR);
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(index->close)(index);
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return (status);
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}
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} while ((c = (index->seq)(index, &key, &data, R_NEXT)) == 0);
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if (c == 0)
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{
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/* An error. */
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(index->close)(index);
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return (-1);
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}
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(index->close)(index);
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return (1);
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}
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/*
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* idx_write_entry()
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*
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* Write out an index file entry.
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*
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* Input:
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* file Name of database file (text version).
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* track Start time of last track (database key).
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* pos Position of entry in text file.
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*
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* Output:
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* 0 Record written.
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* -1 Index file inaccessible, or another error.
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*
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* Note: it is the caller's responsibility to do locking, as it's assumed
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* that this operation will accompany a modification of the main database
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* file and will need to be atomic with that modification.
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*/
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int
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idx_write_entry( char *file, int track, unsigned long pos )
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{
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char *indexname, keyval[8];
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int status;
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DB *index;
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DBT key, data;
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BTREEINFO bti;
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/*
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* Open the index file.
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*/
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indexname = malloc(strlen(file) + sizeof(".ind"));
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if (indexname == NULL)
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return (-1);
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strcpy(indexname, file);
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strcat(indexname, ".ind");
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bti.flags = R_DUP;
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bti.cachesize = 0;
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bti.minkeypage = 0;
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bti.maxkeypage = 0;
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bti.psize = 0;
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bti.lorder = 4321; /* network byte order */
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bti.compare = NULL;
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bti.prefix = NULL;
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index = dbopen(indexname, O_RDWR, 0666, DB_BTREE, &bti);
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free(indexname);
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if (index == NULL)
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return (-1);
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/*
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* Create a new key and value.
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*/
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pos = htonl(pos);
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data.data = &pos;
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data.size = sizeof(pos);
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key.data = keyval;
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key.size = 7;
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sprintf(keyval, "%07d", track);
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status = (index->put)(index, &key, &data, 0);
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(index->close)(index);
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return (status);
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}
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#else /* LIBDB */
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int
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idx_find_entry()
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{
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return (1); /* no record found; text file will be searched. */
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}
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int
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idx_delete_entry()
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{
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return (0);
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}
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int
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idx_write_entry()
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{
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return (0);
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}
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#endif /* LIBDB */
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