libextractor

GNU libextractor
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xm_extractor.c (3069B)

      1 /*
      2  * This file is part of libextractor.
      3  * Copyright (C) 2008, 2009 Toni Ruottu
      4  *
      5  * libextractor is free software; you can redistribute it and/or modify
      6  * it under the terms of the GNU General Public License as published
      7  * by the Free Software Foundation; either version 3, or (at your
      8  * option) any later version.
      9  *
     10  * libextractor is distributed in the hope that it will be useful, but
     11  * WITHOUT ANY WARRANTY; without even the implied warranty of
     12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13  * General Public License for more details.
     14  *
     15  * You should have received a copy of the GNU General Public License
     16  * along with libextractor; see the file COPYING.  If not, write to the
     17  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     18  * Boston, MA 02110-1301, USA.
     19  *
     20  */
     21 /**
     22  * @file plugins/xm_extractor.c
     23  * @brief plugin to support XM files
     24  * @author Toni Ruottu
     25  * @author Christian Grothoff
     26  */
     27 #include "platform.h"
     28 #include "extractor.h"
     29 
     30 
     31 /**
     32  * Header of an XM file.
     33  */
     34 struct Header
     35 {
     36   char magicid[17];
     37   char title[20];
     38   char something[1];
     39   char tracker[20];
     40   char version[2];
     41 };
     42 
     43 
     44 /**
     45  * Give meta data to LE.
     46  *
     47  * @param s utf-8 string meta data value
     48  * @param t type of the meta data
     49  */
     50 #define ADD(s,t) do { if (0 != ec->proc (ec->cls, "xm", t, \
     51                                          EXTRACTOR_METAFORMAT_UTF8, \
     52                                          "text/plain", s, strlen (s) \
     53                                          + 1)) return; \
     54 } while (0)
     55 
     56 
     57 /**
     58  * "extract" metadata from an Extended Module
     59  *
     60  * The XM module format description for XM files
     61  * version $0104 that was written by Mr.H of Triton
     62  * in 1994 was used, while this piece of software
     63  * was originally written.
     64  *
     65  * @param ec extraction context
     66  */
     67 void
     68 EXTRACTOR_xm_extract_method (struct EXTRACTOR_ExtractContext *ec);
     69 
     70 void
     71 EXTRACTOR_xm_extract_method (struct EXTRACTOR_ExtractContext *ec)
     72 {
     73   void *data;
     74   const struct Header *head;
     75   char title[21];
     76   char tracker[21];
     77   char xmversion[8];
     78   size_t n;
     79 
     80   if ((ssize_t) sizeof (struct Header) >
     81       ec->read (ec->cls,
     82                 &data,
     83                 sizeof (struct Header)))
     84     return;
     85   head = data;
     86   /* Check "magic" id bytes */
     87   if (memcmp (head->magicid, "Extended Module: ", 17))
     88     return;
     89   ADD ("audio/x-xm", EXTRACTOR_METATYPE_MIMETYPE);
     90   /* Version of Tracker */
     91   snprintf (xmversion,
     92             sizeof (xmversion),
     93             "%u.%u",
     94             head->version[1],
     95             head->version[0]);
     96   ADD (xmversion, EXTRACTOR_METATYPE_FORMAT_VERSION);
     97   /* Song title */
     98   memcpy (&title, head->title, 20);
     99   n = 19;
    100   while ( (n > 0) && isspace ((unsigned char) title[n]))
    101     n--;
    102   title[n + 1] = '\0';
    103   ADD (title, EXTRACTOR_METATYPE_TITLE);
    104   /* software used for creating the data */
    105   memcpy (&tracker, head->tracker, 20);
    106   n = 19;
    107   while ( (n > 0) && isspace ((unsigned char) tracker[n]))
    108     n--;
    109   tracker[n + 1] = '\0';
    110   ADD (tracker, EXTRACTOR_METATYPE_CREATED_BY_SOFTWARE);
    111   return;
    112 }
    113 
    114 
    115 /* end of xm_extractor.c */