dlls/quartz/amundoc.c

   1 /*
   2  * Copyright (C) Hidenori TAKESHIMA
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19 #include "config.h"
  20
  21 #include <math.h>
  22 #include "windef.h"
  23 #include "wine/obj_base.h"
  24
  25 #include "wine/debug.h"
  26 WINE_DEFAULT_DEBUG_CHANNEL(quartz);
  27
  28 #include "quartz_private.h"
  29
  30 /***********************************************************************
  31  *              AmpFactorToDB (QUARTZ.@)
  32  *
  33  *      undocumented.
  34  *  converting from Amp to dB?
  35  *
  36  */
  37 LONG WINAPI QUARTZ_AmpFactorToDB( LONG amp )
  38 {
  39         LONG    dB;
  40
  41         TRACE( "(%ld)\n", amp );
  42
  43         if ( amp <= 0 || amp > 65536 )
  44                 return 0;
  45
  46         dB = (LONG)(2000.0 * log10((double)amp / 65536.0) + 0.5);
  47         if ( dB >= 0 ) dB = 0;
  48         if ( dB < -10000 ) dB = -10000;
  49
  50         return dB;
  51 }
  52
  53 /***********************************************************************
  54  *              DBToAmpFactor (QUARTZ.@)
  55  *
  56  *      undocumented.
  57  *  converting from dB to Amp?
  58  */
  59 LONG WINAPI QUARTZ_DBToAmpFactor( LONG dB )
  60 {
  61         LONG    amp;
  62
  63         TRACE( "(%ld)\n", dB );
  64
  65         if ( dB >= 0 )
  66                 return 65535;
  67         if ( dB < -10000 )
  68                 return 0;
  69
  70         amp = (LONG)(pow(10.0,dB / 2000.0) * 65536.0 + 0.5);
  71         if ( amp <= 0 ) amp = 1;
  72         if ( amp >= 65536 ) amp = 65535;
  73
  74         return amp;
  75 }
  76