utils/wxMMedia/sndpcm.cpp

   1 ////////////////////////////////////////////////////////////////////////////////
   2 // Name:       sndpcm.cpp
   3 // Purpose:    wxMMedia
   4 // Author:     Guilhem Lavaux
   5 // Created:    1998
   6 // Updated:    1999
   7 // Copyright:  (C) 1997, 1998, 1999, Guilhem Lavaux
   8 // License:    wxWindows license
   9 ////////////////////////////////////////////////////////////////////////////////
  10 #ifdef __GNUG__
  11 #pragma implementation "sndpcm.h"
  12 #endif
  13 #include "sndsnd.h"
  14 #include "sndpcm.h"
  15
  16 #define WX_BIG_ENDIAN 0
  17
  18 wxSoundPcmCodec::wxSoundPcmCodec()
  19   : wxSoundCodec()
  20 {
  21   m_orig_format.SetCodecCreate(FALSE);
  22   m_orig_format.SetCodecNo(WXSOUND_PCM);
  23 }
  24
  25 wxSoundPcmCodec::~wxSoundPcmCodec()
  26 {
  27 }
  28
  29 size_t wxSoundPcmCodec::GetByteRate() const
  30 {
  31   return (m_orig_format.GetBps()/8)*
  32           m_orig_format.GetSampleRate()*
  33           m_orig_format.GetChannels();
  34 }
  35
  36 wxSoundDataFormat wxSoundPcmCodec::GetPreferredFormat(int codec) const
  37 {
  38   wxSoundDataFormat prefFormat;
  39
  40   prefFormat = m_orig_format;
  41   return prefFormat;
  42 }
  43
  44 // ---------------------------------------------------------------------------
  45 // Main part of the decoder
  46 // ---------------------------------------------------------------------------
  47
  48 void wxSoundPcmCodec::Decode()
  49 {
  50   if (m_io_format == m_orig_format) {
  51     CopyToOutput();
  52     return;
  53   }
  54
  55   // Swap bytes
  56   switch (m_io_format.GetBps()) {
  57   case 8:
  58     InputSign8();
  59     break;
  60   case 16:
  61     InputSwapAndSign16();
  62     break;
  63   case 32:
  64   case 64:
  65   default:
  66     break;
  67   }
  68 }
  69
  70 // ---------------------------------------------------------------------------
  71 // Change the sign of a 8-bit sample.
  72
  73 #define GET() (m_in_sound->GetChar())
  74 #define PUT(c) (m_out_sound->PutChar(c))
  75
  76 void wxSoundPcmCodec::InputSign8()
  77 {
  78   unsigned char signer = 0;
  79
  80   if (m_io_format.GetSign() != m_orig_format.GetSign())
  81     signer = 128;
  82
  83   while (StreamOk())
  84     PUT(GET() + signer);
  85 }
  86
  87 // ---------------------------------------------------------------------------
  88 // Swap bytes and change the sign of a 16-bit sample.
  89
  90 void wxSoundPcmCodec::InputSwapAndSign16()
  91 {
  92   unsigned short signer1 = 0, signer2 = 0;
  93   bool swap = (m_io_format.GetByteOrder() != m_orig_format.GetByteOrder());
  94   register char temp, temp2;
  95
  96   if (m_io_format.GetSign() != m_orig_format.GetSign()) {
  97     if (m_io_format.GetByteOrder() == wxSND_SAMPLE_LE)
  98       signer2 = 0x80;
  99     else
 100       signer1 = 0x80;
 101   }
 102
 103   if (swap) {
 104     while (StreamOk()) {
 105       temp = GET();
 106       temp2 = GET();
 107       PUT(temp2 ^ signer2);
 108       if (!StreamOk()) {
 109         m_in_sound->WriteBack(temp);
 110         m_in_sound->WriteBack(temp2);
 111         break;
 112       }
 113       PUT(temp ^ signer1);
 114     }
 115   } else {
 116     while (StreamOk()) {
 117       temp = GET();
 118       temp2 = GET();
 119       PUT(temp ^ signer1);
 120       if (!StreamOk()) {
 121         m_in_sound->WriteBack(temp);
 122         m_in_sound->WriteBack(temp2);
 123         break;
 124       }
 125       PUT(GET() ^ signer2);
 126     }
 127   }
 128 }
 129
 130 // ---------------------------------------------------------------------------
 131 // Encoder part.
 132 // ---------------------------------------------------------------------------
 133
 134 void wxSoundPcmCodec::OutputSign8()
 135 {
 136   unsigned char signer = 0;
 137
 138   if (m_io_format.GetSign() != m_orig_format.GetSign())
 139     signer = 128;
 140
 141   while (StreamOk())
 142     PUT((char)(GET() + signer));
 143 }
 144
 145 // ---------------------------------------------------------------------------
 146
 147 void wxSoundPcmCodec::OutputSwapAndSign16()
 148 {
 149   bool swap = (m_io_format.GetByteOrder() != m_orig_format.GetByteOrder());
 150   unsigned short signer1 = 0, signer2 = 0;
 151   register char temp, temp2;
 152
 153   if (m_io_format.GetSign() != m_orig_format.GetSign())
 154     if (m_io_format.GetByteOrder() == wxSND_SAMPLE_LE)
 155       signer1 = 0x80;
 156     else
 157       signer2 = 0x80;
 158
 159   if (swap) {
 160     while (StreamOk()) {
 161       temp = GET();
 162       temp2 = GET();
 163       PUT(temp2 ^ signer1);
 164       if (!StreamOk()) {
 165         m_in_sound->WriteBack(temp);
 166         m_in_sound->WriteBack(temp2);
 167         break;
 168       }
 169       PUT(temp ^ signer2);
 170     }
 171   } else {
 172     while (StreamOk()) {
 173       temp = GET();
 174       temp2 = GET();
 175       PUT(temp ^ signer1);
 176       if (!StreamOk()) {
 177         m_in_sound->WriteBack(temp);
 178         m_in_sound->WriteBack(temp2);
 179         break;
 180       }
 181       PUT(temp2 ^ signer2);
 182     }
 183   }
 184
 185 }
 186
 187 // ---------------------------------------------------------------------------
 188
 189 void wxSoundPcmCodec::Encode()
 190 {
 191   if (m_io_format == m_orig_format) {
 192     CopyToOutput();
 193     return;
 194   }
 195
 196   // Swap bytes
 197   switch (m_io_format.GetBps()) {
 198   case 8:
 199     OutputSign8();
 200     break;
 201   case 16:
 202     OutputSwapAndSign16();
 203     break;
 204   case 32:
 205   case 64:
 206   default:
 207     break;
 208   }
 209 }