modules/stream_filter/adf.c

   1 /*****************************************************************************
   2  * adf.c ADF stream filter
   3  *****************************************************************************
   4  * Copyright (C) 2016 VideoLAN Authors
   5  *
   6  * Author: Tristan Matthews <tmatth@videolan.org>
   7  * Based on record.c by: Laurent Aimar <fenrir _AT_ videolan _DOT_ org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <vlc_common.h>
  32 #include <vlc_plugin.h>
  33 #include <vlc_stream.h>
  34
  35 static int Open( vlc_object_t * );
  36
  37 vlc_module_begin()
  38     set_shortname( "adf" )
  39     set_category( CAT_INPUT )
  40     set_subcategory( SUBCAT_INPUT_STREAM_FILTER )
  41     set_capability( "stream_filter", 30 )
  42     set_description( N_( "ADF stream filter" ) )
  43     set_callbacks( Open, NULL )
  44 vlc_module_end()
  45
  46 static int Control( stream_t *p_stream, int i_query, va_list args )
  47 {
  48     return vlc_stream_vaControl( p_stream->p_source, i_query, args );
  49 }
  50
  51 static ssize_t Read( stream_t *s, void *buffer, size_t i_read )
  52 {
  53     const ssize_t i_ret = vlc_stream_Read( s->p_source, buffer, i_read );
  54     if( i_ret < 1 ) return i_ret;
  55
  56     uint8_t *p_buffer = buffer;
  57     static const uint8_t ADF_XOR_MASK = 34;
  58     for( ssize_t i = 0; i < i_ret; ++i )
  59         p_buffer[i] ^= ADF_XOR_MASK;
  60     return i_ret;
  61 }
  62
  63 static int Seek( stream_t *s, uint64_t offset )
  64 {
  65     return vlc_stream_Seek( s->p_source, offset );
  66 }
  67
  68 static int Open( vlc_object_t *p_object )
  69 {
  70     stream_t *p_stream = (stream_t *)p_object;
  71
  72     /* Require .adf extension unless forced. */
  73     if( !p_stream->obj.force )
  74     {
  75         if( !p_stream->psz_url )
  76             return VLC_EGENERIC;
  77         const char *psz_ext = strrchr( p_stream->psz_url, '.' );
  78         if( !psz_ext || strncmp( psz_ext, ".adf", 4 ) )
  79             return VLC_EGENERIC;
  80     }
  81
  82     const uint8_t *peek;
  83     if( vlc_stream_Peek( p_stream->p_source, &peek, 3 ) < 3 )
  84         return VLC_EGENERIC;
  85
  86     /* Probe for XOR'd ID3 tag. */
  87     if( memcmp( peek, "\x6B\x66\x11", 3 ) )
  88         return VLC_EGENERIC;
  89
  90     p_stream->pf_read = Read;
  91     p_stream->pf_seek = Seek;
  92     p_stream->pf_control = Control;
  93
  94     return VLC_SUCCESS;
  95 }