Adds trunk/talk folder of revision 359 from libjingles google code to
trunk/talk


git-svn-id: http://webrtc.googlecode.com/svn/trunk@4318 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/talk/sound/soundsysteminterface.h b/talk/sound/soundsysteminterface.h
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+++ b/talk/sound/soundsysteminterface.h
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+/*
+ * libjingle
+ * Copyright 2004--2010, Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef TALK_SOUND_SOUNDSYSTEMINTERFACE_H_
+#define TALK_SOUND_SOUNDSYSTEMINTERFACE_H_
+
+#include <vector>
+
+#include "talk/base/constructormagic.h"
+
+namespace cricket {
+
+class SoundDeviceLocator;
+class SoundInputStreamInterface;
+class SoundOutputStreamInterface;
+
+// Interface for a platform's sound system.
+// Implementations must guarantee thread-safety for at least the following use
+// cases:
+// 1) Concurrent enumeration and opening of devices from different threads.
+// 2) Concurrent use of different Sound(Input|Output)StreamInterface
+// instances from different threads (but concurrent use of the _same_ one from
+// different threads need not be supported).
+class SoundSystemInterface {
+ public:
+  typedef std::vector<SoundDeviceLocator *> SoundDeviceLocatorList;
+
+  enum SampleFormat {
+    // Only one supported sample format at this time.
+    // The values here may be used in lookup tables, so they shouldn't change.
+    FORMAT_S16LE = 0,
+  };
+
+  enum Flags {
+    // Enable reporting the current stream latency in
+    // Sound(Input|Output)StreamInterface. See those classes for more details.
+    FLAG_REPORT_LATENCY = (1 << 0),
+  };
+
+  struct OpenParams {
+    // Format for the sound stream.
+    SampleFormat format;
+    // Sampling frequency in hertz.
+    unsigned int freq;
+    // Number of channels in the PCM stream.
+    unsigned int channels;
+    // Misc flags. Should be taken from the Flags enum above.
+    int flags;
+    // Desired latency, measured as number of bytes of sample data
+    int latency;
+  };
+
+  // Special values for the "latency" field of OpenParams.
+  // Use this one to say you don't care what the latency is. The sound system
+  // will optimize for other things instead.
+  static const int kNoLatencyRequirements = -1;
+  // Use this one to say that you want the sound system to pick an appropriate
+  // small latency value. The sound system may pick the minimum allowed one, or
+  // a slightly higher one in the event that the true minimum requires an
+  // undesirable trade-off.
+  static const int kLowLatency = 0;
+ 
+  // Max value for the volume parameters for Sound(Input|Output)StreamInterface.
+  static const int kMaxVolume = 255;
+  // Min value for the volume parameters for Sound(Input|Output)StreamInterface.
+  static const int kMinVolume = 0;
+
+  // Helper for clearing a locator list and deleting the entries.
+  static void ClearSoundDeviceLocatorList(SoundDeviceLocatorList *devices);
+
+  virtual ~SoundSystemInterface() {}
+
+  virtual bool Init() = 0;
+  virtual void Terminate() = 0;
+
+  // Enumerates the available devices. (Any pre-existing locators in the lists
+  // are deleted.)
+  virtual bool EnumeratePlaybackDevices(SoundDeviceLocatorList *devices) = 0;
+  virtual bool EnumerateCaptureDevices(SoundDeviceLocatorList *devices) = 0;
+
+  // Gets a special locator for the default device.
+  virtual bool GetDefaultPlaybackDevice(SoundDeviceLocator **device) = 0;
+  virtual bool GetDefaultCaptureDevice(SoundDeviceLocator **device) = 0;
+
+  // Opens the given device, or returns NULL on error.
+  virtual SoundOutputStreamInterface *OpenPlaybackDevice(
+      const SoundDeviceLocator *device,
+      const OpenParams &params) = 0;
+  virtual SoundInputStreamInterface *OpenCaptureDevice(
+      const SoundDeviceLocator *device,
+      const OpenParams &params) = 0;
+
+  // A human-readable name for this sound system.
+  virtual const char *GetName() const = 0;
+
+ protected:
+  SoundSystemInterface() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SoundSystemInterface);
+};
+
+}  // namespace cricket
+
+#endif  // TALK_SOUND_SOUNDSYSTEMINTERFACE_H_