Cygwin: Implement sound mixer device.

This patch adds implementation of OSS-based sound mixer device. This
allows applications to change the sound playing volume.

NOTE: Currently, the recording volume cannot be changed.

Reviewed-by: Corinna Vinschen <corinna@vinschen.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>

1 files changed, 152 insertions, 0 deletions

diff --git a/winsup/cygwin/fhandler/mixer.cc b/winsup/cygwin/fhandler/mixer.cc
new file mode 100644
index 000000000..fabd397b7
--- /dev/null
+++ b/winsup/cygwin/fhandler/mixer.cc
@@ -0,0 +1,152 @@
+/* fhandler_dev_mixer: code to emulate OSS sound model /dev/mixer
+
+   Written by Takashi Yano <takashi.yano@nifty.ne.jp>
+
+This file is part of Cygwin.
+
+This software is a copyrighted work licensed under the terms of the
+Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
+details. */
+
+#include "winsup.h"
+#include <sys/soundcard.h>
+#include "cygerrno.h"
+#include "path.h"
+#include "fhandler.h"
+#include "dtable.h"
+#include "cygheap.h"
+
+ssize_t
+fhandler_dev_mixer::write (const void *ptr, size_t len)
+{
+  set_errno (EINVAL);
+  return -1;
+}
+
+void
+fhandler_dev_mixer::read (void *ptr, size_t& len)
+{
+  len = -1;
+  set_errno (EINVAL);
+}
+
+int
+fhandler_dev_mixer::open (int flags, mode_t)
+{
+  int ret = -1, err = 0;
+  switch (flags & O_ACCMODE)
+    {
+    case O_RDWR:
+    case O_WRONLY:
+    case O_RDONLY:
+      if (waveInGetNumDevs () == 0 && waveOutGetNumDevs () == 0)
+	err = ENXIO;
+      break;
+    default:
+      err = EINVAL;
+    }
+
+  if (err)
+    set_errno (err);
+  else
+    {
+      ret = open_null (flags);
+      rec_source = SOUND_MIXER_MIC;
+    }
+
+  return ret;
+}
+
+static DWORD
+volume_oss_to_winmm (int vol_oss)
+{
+  unsigned int vol_l, vol_r;
+  DWORD vol_winmm;
+
+  vol_l = ((unsigned int) vol_oss) & 0xff;
+  vol_r = ((unsigned int) vol_oss) >> 8;
+  vol_l = min ((vol_l * 65535 + 50) / 100, 65535);
+  vol_r = min ((vol_r * 65535 + 50) / 100, 65535);
+  vol_winmm = (vol_r << 16) | vol_l;
+
+  return vol_winmm;
+}
+
+static int
+volume_winmm_to_oss (DWORD vol_winmm)
+{
+  int vol_l, vol_r;
+
+  vol_l = vol_winmm & 0xffff;
+  vol_r = vol_winmm >> 16;
+  vol_l = min ((vol_l * 100 + 32768) / 65535, 100);
+  vol_r = min ((vol_r * 100 + 32768) / 65535, 100);
+  return (vol_r << 8) | vol_l;
+}
+
+int
+fhandler_dev_mixer::ioctl (unsigned int cmd, void *buf)
+{
+  int ret = 0;
+  DWORD vol;
+  switch (cmd)
+    {
+    case SOUND_MIXER_READ_DEVMASK:
+      *(int *) buf = SOUND_MASK_VOLUME | SOUND_MASK_MIC | SOUND_MASK_LINE;
+      break;
+    case SOUND_MIXER_READ_RECMASK:
+      *(int *) buf = SOUND_MASK_MIC | SOUND_MASK_LINE;
+      break;
+    case SOUND_MIXER_READ_STEREODEVS:
+      *(int *) buf = SOUND_MASK_VOLUME | SOUND_MASK_LINE;
+      break;
+    case SOUND_MIXER_READ_CAPS:
+      *(int *) buf = SOUND_CAP_EXCL_INPUT;
+      break;
+    case MIXER_WRITE (SOUND_MIXER_RECSRC):
+      /* Dummy implementation */
+      if (*(int *) buf == 0 || ((*(int *) buf) & SOUND_MASK_MIC))
+	rec_source = SOUND_MIXER_MIC;
+      else if ((*(int *) buf) & SOUND_MASK_LINE)
+	rec_source = SOUND_MIXER_LINE;
+      break;
+    case MIXER_READ (SOUND_MIXER_RECSRC):
+      /* Dummy implementation */
+      *(int *) buf = 1 << rec_source;
+      break;
+    case MIXER_WRITE (SOUND_MIXER_VOLUME):
+      vol = volume_oss_to_winmm (*(int *) buf);
+      if (waveOutSetVolume ((HWAVEOUT)WAVE_MAPPER, vol) != MMSYSERR_NOERROR)
+	{
+	  set_errno (EINVAL);
+	  ret = -1;
+	}
+      break;
+    case MIXER_READ (SOUND_MIXER_VOLUME):
+      DWORD vol;
+      if (waveOutGetVolume ((HWAVEOUT)WAVE_MAPPER, &vol) != MMSYSERR_NOERROR)
+	{
+	  set_errno (EINVAL);
+	  ret = -1;
+	  break;
+	}
+      *(int *) buf = volume_winmm_to_oss (vol);
+      break;
+    default:
+      for (int i = 0; i < SOUND_MIXER_NRDEVICES; i++)
+	{
+	  if (cmd == (unsigned int) MIXER_WRITE (i))
+	    goto out;
+	  if (cmd == (unsigned int) MIXER_READ (i))
+	    {
+	      *(int *) buf = 0;
+	      goto out;
+	    }
+	}
+      set_errno (EINVAL);
+      ret = -1;
+      break;
+    }
+out:
+  return ret;
+}