libextractor

sid_extractor.c (5576B)

---

 /*
  * This file is part of libextractor.
  * Copyright (C) 2006, 2007, 2012 Vidyut Samanta and Christian Grothoff
  *
  * libextractor is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published
  * by the Free Software Foundation; either version 3, or (at your
  * option) any later version.
  *
  * libextractor is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with libextractor; see the file COPYING.  If not, write to the
  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 /**
  * @file plugins/sid_extractor.c
  * @brief plugin to support Scream Tracker (S3M) files
  * @author Toni Ruottu
  * @author Christian Grothoff
  */
 #include "platform.h"
 #include "extractor.h"
 
 
 /* SID flags */
 #define MUSPLAYER_FLAG   0x01
 #define PLAYSID_FLAG     0x02
 #define PAL_FLAG         0x04
 #define NTSC_FLAG        0x08
 #define MOS6581_FLAG     0x10
 #define MOS8580_FLAG     0x20
 
 /**
  * A "SID word".
  */
 typedef char sidwrd[2];
 
 /**
  * A "SID long".
  */
 typedef char sidlongwrd[4];
 
 /**
  * Header of a SID file.
  */
 struct header
 {
   /**
    * Magic string.
    */
   char magicid[4];
 
   /**
    * Version number.
    */
   sidwrd sidversion;
 
   /**
    * Unknown.
    */
   sidwrd dataoffset;
 
   /**
    * Unknown.
    */
   sidwrd loadaddr;
 
   /**
    * Unknown.
    */
   sidwrd initaddr;
 
   /**
    * Unknown.
    */
   sidwrd playaddr;
 
   /**
    * Number of songs in file.
    */
   sidwrd songs;
 
   /**
    * Starting song.
    */
   sidwrd firstsong;
 
   /**
    * Unknown.
    */
   sidlongwrd speed;
 
   /**
    * Title of the album.
    */
   char title[32];
 
   /**
    * Name of the artist.
    */
   char artist[32];
 
   /**
    * Copyright information.
    */
   char copyright[32];
 
   /* version 2 specific fields start */
 
   /**
    * Flags
    */
   sidwrd flags;
 
   /**
    * Unknown.
    */
   char startpage;
 
   /**
    * Unknown.
    */
   char pagelength;
 
   /**
    * Unknown.
    */
   sidwrd reserved;
 };
 
 
 /**
  * Convert a 'sidword' to an integer.
  *
  * @param data the sidword
  * @return corresponding integer value
  */
 static int
 sidword (const sidwrd data)
 {
   return (unsigned char) data[0] * 0x100 + (unsigned char) data[1];
 }
 
 
 /**
  * Give metadata to LE; return if 'proc' returns non-zero.
  *
  * @param s metadata value as UTF8
  * @param t metadata type to use
  */
 #define ADD(s,t) do { if (0 != ec->proc (ec->cls, "sid", t, \
                                          EXTRACTOR_METAFORMAT_UTF8, \
                                          "text/plain", s, strlen (s) \
                                          + 1)) return; \
 } while (0)
 
 
 /**
  * Extract metadata from SID files.
  *
  * @param ec extraction context
  */
 void
 EXTRACTOR_sid_extract_method (struct EXTRACTOR_ExtractContext *ec)
 {
   unsigned int flags;
   int version;
   char album[33];
   char artist[33];
   char copyright[33];
   char songs[32];
   char startingsong[32];
   char sidversion[32];
   const struct header *head;
   void *data;
 
   if ((ssize_t) sizeof (struct header) >
       ec->read (ec->cls,
                 &data,
                 sizeof (struct header)))
     return;
   head = data;
 
   /* Check "magic" id bytes */
   if ( (0 != memcmp (head->magicid, "PSID", 4)) &&
        (0 != memcmp (head->magicid, "RSID", 4)) )
     return;
 
   /* Mime-type */
   ADD ("audio/prs.sid", EXTRACTOR_METATYPE_MIMETYPE);
 
   /* Version of SID format */
   version = sidword (head->sidversion);
   snprintf (sidversion,
             sizeof (sidversion),
             "%d",
             version);
   ADD (sidversion, EXTRACTOR_METATYPE_FORMAT_VERSION);
 
   /* Get song count */
   snprintf (songs,
             sizeof (songs),
             "%d", sidword (head->songs));
   ADD (songs, EXTRACTOR_METATYPE_SONG_COUNT);
 
   /* Get number of the first song to be played */
   snprintf (startingsong,
             sizeof (startingsong),
             "%d",
             sidword (head->firstsong));
   ADD (startingsong, EXTRACTOR_METATYPE_STARTING_SONG);
 
   /* name, artist, copyright fields */
   memcpy (&album, head->title, 32);
   album[32] = '\0';
   ADD (album, EXTRACTOR_METATYPE_ALBUM);
 
   memcpy (&artist, head->artist, 32);
   artist[32] = '\0';
   ADD (artist, EXTRACTOR_METATYPE_ARTIST);
 
   memcpy (&copyright, head->copyright, 32);
   copyright[32] = '\0';
   ADD (copyright, EXTRACTOR_METATYPE_COPYRIGHT);
 
   if (version < 2)
     return;
 
   /* Version 2 specific options follow
    *
    * Note: Had some troubles understanding specification
    * on the flags in version 2. I hope this is correct.
    */flags = sidword (head->flags);
   /* MUS data */
   if (0 != (flags & MUSPLAYER_FLAG))
     ADD ("Compute!'s Sidplayer", EXTRACTOR_METATYPE_CREATED_BY_SOFTWARE);
 
   /* PlaySID data */
   if (0 != (flags & PLAYSID_FLAG))
     ADD ("PlaySID", EXTRACTOR_METATYPE_CREATED_BY_SOFTWARE);
 
 
   /* PAL or NTSC */
   if (0 != (flags & NTSC_FLAG))
     ADD ("PAL/NTSC", EXTRACTOR_METATYPE_BROADCAST_TELEVISION_SYSTEM);
   else if (0 != (flags & PAL_FLAG))
     ADD ("PAL", EXTRACTOR_METATYPE_BROADCAST_TELEVISION_SYSTEM);
 
   /* Detect SID Chips suitable for play the files */
   if (0 != (flags & MOS8580_FLAG))
     ADD ("MOS6581/MOS8580", EXTRACTOR_METATYPE_TARGET_ARCHITECTURE);
   else if (0 != (flags & MOS6581_FLAG))
     ADD ("MOS6581", EXTRACTOR_METATYPE_TARGET_ARCHITECTURE);
 }
 
 
 /* end of sid_extractor.c */