refactor and start working on a pulseaudio backend

.gitignore

@@ -1,3 +1,5 @@
 .idea
 cmake-build*
 .DS_Store
+*.user
+build

CMakeLists.txt

@@ -7,14 +7,29 @@ cmake_minimum_required(VERSION 3.12)
 project(libstdaudio)
 
 set(CMAKE_CXX_STANDARD 17)
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror -O0 -fsanitize=undefined")
 if (APPLE)
     set(CMAKE_EXE_LINKER_FLAGS "-framework CoreAudio")
 endif ()
 
+# add the headers to at least one target so that they get
+# parsed as part of the project in some IDEs
+set(headers
+    include/__audio_base.h
+    include/__audio_buffer.h
+    include/__audio_device.h
+    include/__audio_exception.h
+    include/__dynamic_library.h
+    include/audio
+    include/cpp/span.hpp
+    include/audio_backend/__coreaudio_backend.h
+    include/audio_backend/__null_backend.h
+    include/audio_backend/__portaudio_backend.h
+    include/audio_backend/__pulseaudio_backend.h
+    )
 include_directories(include)
 
-add_executable(white_noise examples/white_noise.cpp)
+add_executable(white_noise examples/white_noise.cpp ${headers})
 target_link_libraries(white_noise PRIVATE ${CMAKE_DL_LIBS})
 add_executable(print_devices examples/print_devices.cpp)
 target_link_libraries(print_devices PRIVATE ${CMAKE_DL_LIBS})

examples/sine_wave.cpp

@@ -20,18 +20,20 @@ int main() {
   float delta = 2.0f * frequency_hz * float(M_PI / device->get_sample_rate());
   float phase = 0;
 
+  static int64_t i = 0;
   device->connect([=](audio_device& device, audio_device_buffers& buffers) mutable {
     auto buffer = *buffers.output_buffer();
     for (int frame = 0; frame < buffer.size_frames(); ++frame) {
-      float next_sample = std::sin(phase);
+      float next_sample_1 = std::sin(phase);
+      float next_sample_2 = 0.f;std::sin(2.0f * frequency_hz * float(M_PI * double(i++) / device.get_sample_rate()));
       phase += delta;
       for (int channel = 0; channel < buffer.size_channels(); ++channel) {
-        buffer(frame, channel) = next_sample;
+        buffer(frame, channel) = next_sample_1 - next_sample_2;
       }
     }
   });
 
   device->start();
-  std::this_thread::sleep_for(std::chrono::seconds(2));
+  std::this_thread::sleep_for(std::chrono::seconds(20));
   device->stop();
-}
+}

include/__audio_base.h

@@ -0,0 +1,41 @@
+#pragma once
+
+#include <optional>
+#include <cassert>
+#include <string_view>
+#include <atomic>
+
+// TODO: this is a temporary measure until std::span becomes available
+#include "cpp/span.hpp"
+using namespace TCB_SPAN_NAMESPACE_NAME;
+
+#define _LIBSTDAUDIO_NAMESPACE std::experimental
+
+#define _LIBSTDAUDIO_NAMESPACE_BEGIN namespace _LIBSTDAUDIO_NAMESPACE {
+#define _LIBSTDAUDIO_NAMESPACE_END }
+
+_LIBSTDAUDIO_NAMESPACE_BEGIN
+
+struct audio_null_driver_t {};
+
+#ifdef __APPLE__
+  struct __coreaudio_driver_t {};
+  using audio_default_driver_t = __coreaudio_driver_t;
+#else
+
+#if __has_include(<pulse/pulseaudio.h>)
+  struct __pulseaudio_driver_t {};
+#endif
+#if __has_include(<portaudio.h>)
+  struct __portaudio_driver_t {};
+#endif
+
+#if __has_include(<pulse/pulseaudio.h>)
+  using audio_default_driver_t = __pulseaudio_driver_t;
+#elif __has_include(<portaudio.h>)
+  using audio_default_driver_t = __portaudio_driver_t;
+#endif
+#endif // __APPLE__
+
+_LIBSTDAUDIO_NAMESPACE_END
+

include/__audio_buffer.h

@@ -4,6 +4,8 @@
 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
 
 #pragma once
+#include <__audio_base.h>
+
 _LIBSTDAUDIO_NAMESPACE_BEGIN
 
 struct audio_buffer_order_interleaved {};

include/__audio_device.h

@@ -4,6 +4,7 @@
 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
 
 #pragma once
+#include <__audio_base.h>
 
 _LIBSTDAUDIO_NAMESPACE_BEGIN
 

include/__audio_exception.h

@@ -0,0 +1,13 @@
+#pragma once
+#include <__audio_base.h>
+#include <stdexcept>
+
+_LIBSTDAUDIO_NAMESPACE_BEGIN
+
+struct audio_device_exception : public runtime_error {
+  explicit audio_device_exception(const char* what)
+    : runtime_error(what) {
+  }
+};
+
+_LIBSTDAUDIO_NAMESPACE_END

include/__dynamic_library.h

@@ -0,0 +1,70 @@
+#pragma once
+#include <__audio_base.h>
+
+#if defined(_WIN32)
+#define __STDAUDIO_HAS_DYLIB 1
+#include <windows.h>
+#elif __has_include(<dlfcn.h>)
+#define __STDAUDIO_HAS_DYLIB 1
+#include <dlfcn.h>
+#endif
+
+_LIBSTDAUDIO_NAMESPACE_BEGIN
+#if __STDAUDIO_HAS_DYLIB
+class __dynamic_library
+{
+public:
+  explicit __dynamic_library(const char* const so) /* not noexcept - some DLL constructors can throw */
+  {
+#ifdef _WIN32
+    impl = (void*)LoadLibraryA(so);
+#else
+    impl = dlopen(so, RTLD_LAZY | RTLD_LOCAL | RTLD_NODELETE);
+#endif
+  }
+
+  __dynamic_library(const __dynamic_library&) noexcept = delete;
+  __dynamic_library& operator=(const __dynamic_library&) noexcept = delete;
+  __dynamic_library(__dynamic_library&& other)
+  {
+    impl = other.impl;
+    other.impl = nullptr;
+  }
+
+  __dynamic_library& operator=(__dynamic_library&& other) noexcept
+  {
+    impl = other.impl;
+    other.impl = nullptr;
+    return *this;
+  }
+
+  ~__dynamic_library()
+  {
+    if (impl)
+    {
+#ifdef _WIN32
+      FreeLibrary((HMODULE)impl);
+#else
+      dlclose(impl);
+#endif
+    }
+  }
+
+  template <typename T>
+  T symbol(const char* const sym) const noexcept
+  {
+#ifdef _WIN32
+    return (T)GetProcAddress((HMODULE)impl, sym);
+#else
+    return (T)dlsym(impl, sym);
+#endif
+  }
+
+  operator bool() const { return bool(impl); }
+
+private:
+  void* impl{};
+};
+#endif
+
+_LIBSTDAUDIO_NAMESPACE_END

include/audio

@@ -4,39 +4,7 @@
 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
 
 #pragma once
-
-#include <optional>
-#include <cassert>
-#include <string_view>
-#include <atomic>
-
-// TODO: this is a temporary measure until std::span becomes available
-#include "cpp/span.hpp"
-using namespace TCB_SPAN_NAMESPACE_NAME;
-
-#define _LIBSTDAUDIO_NAMESPACE std::experimental
-
-#define _LIBSTDAUDIO_NAMESPACE_BEGIN namespace _LIBSTDAUDIO_NAMESPACE {
-#define _LIBSTDAUDIO_NAMESPACE_END }
-
-_LIBSTDAUDIO_NAMESPACE_BEGIN
-
-struct audio_null_driver_t {};
-
-#ifdef __APPLE__
-  struct __coreaudio_driver_t {};
-  using audio_default_driver_t = __coreaudio_driver_t;
-#else
-
-#if __has_include(<portaudio.h>)
-  struct __portaudio_driver_t {};
-  using audio_default_driver_t = __portaudio_driver_t;
-#endif
-
-#endif // __APPLE__
-
-_LIBSTDAUDIO_NAMESPACE_END
-
+#include <__audio_base.h>
 #include <__audio_buffer.h>
 #include <__audio_device.h>
 #include <audio_backend/__null_backend.h>
@@ -46,4 +14,7 @@ _LIBSTDAUDIO_NAMESPACE_END
 #endif // __APPLE__
 #if __has_include(<portaudio.h>)
   #include <audio_backend/__portaudio_backend.h>
-#endif // __APPLE__
+#endif
+#if __has_include(<pulse/pulseaudio.h>)
+  #include <audio_backend/__pulseaudio_backend.h>
+#endif

include/audio_backend/__coreaudio_backend.h

@@ -5,6 +5,10 @@
 
 #pragma once
 
+#include <__audio_base.h>
+#include <__audio_device.h>
+#include <__audio_buffer.h>
+#include <__audio_exception.h>
 #include <cctype>
 #include <string>
 #include <iostream>
@@ -72,12 +76,6 @@ class __coreaudio_util {
   }
 };
 
-struct audio_device_exception : public runtime_error {
-  explicit audio_device_exception(const char* what)
-    : runtime_error(what) {
-  }
-};
-
 using __coreaudio_device = audio_basic_device<__coreaudio_driver_t>;
 
 template<>