utils/wxMMedia/sndpcm.cpp

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