Convert the SDL2 backend to C++

1 files changed, 291 insertions, 0 deletions

diff --git a/Alc/backends/sdl2.cpp b/Alc/backends/sdl2.cpp
new file mode 100644
index 00000000..cf81e1f0
--- /dev/null
+++ b/Alc/backends/sdl2.cpp
@@ -0,0 +1,291 @@
+/**
+ * OpenAL cross platform audio library
+ * Copyright (C) 2018 by authors.
+ * This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Library General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ *  License along with this library; if not, write to the
+ *  Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ * Or go to http://www.gnu.org/copyleft/lgpl.html
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <SDL2/SDL.h>
+
+#include <string>
+
+#include "alMain.h"
+#include "alu.h"
+#include "threads.h"
+#include "compat.h"
+
+#include "backends/base.h"
+
+
+#ifdef _WIN32
+#define DEVNAME_PREFIX "OpenAL Soft on "
+#else
+#define DEVNAME_PREFIX ""
+#endif
+
+struct ALCsdl2Backend final : public ALCbackend {
+    SDL_AudioDeviceID deviceID;
+    ALsizei frameSize;
+
+    ALuint Frequency;
+    enum DevFmtChannels FmtChans;
+    enum DevFmtType     FmtType;
+    ALuint UpdateSize;
+};
+
+static void ALCsdl2Backend_Construct(ALCsdl2Backend *self, ALCdevice *device);
+static void ALCsdl2Backend_Destruct(ALCsdl2Backend *self);
+static ALCenum ALCsdl2Backend_open(ALCsdl2Backend *self, const ALCchar *name);
+static ALCboolean ALCsdl2Backend_reset(ALCsdl2Backend *self);
+static ALCboolean ALCsdl2Backend_start(ALCsdl2Backend *self);
+static void ALCsdl2Backend_stop(ALCsdl2Backend *self);
+static DECLARE_FORWARD2(ALCsdl2Backend, ALCbackend, ALCenum, captureSamples, void*, ALCuint)
+static DECLARE_FORWARD(ALCsdl2Backend, ALCbackend, ALCuint, availableSamples)
+static DECLARE_FORWARD(ALCsdl2Backend, ALCbackend, ClockLatency, getClockLatency)
+static void ALCsdl2Backend_lock(ALCsdl2Backend *self);
+static void ALCsdl2Backend_unlock(ALCsdl2Backend *self);
+DECLARE_DEFAULT_ALLOCATORS(ALCsdl2Backend)
+
+DEFINE_ALCBACKEND_VTABLE(ALCsdl2Backend);
+
+static const ALCchar defaultDeviceName[] = DEVNAME_PREFIX "Default Device";
+
+static void ALCsdl2Backend_Construct(ALCsdl2Backend *self, ALCdevice *device)
+{
+    new (self) ALCsdl2Backend{};
+    ALCbackend_Construct(STATIC_CAST(ALCbackend, self), device);
+    SET_VTABLE2(ALCsdl2Backend, ALCbackend, self);
+
+    self->deviceID = 0;
+    self->frameSize = FrameSizeFromDevFmt(device->FmtChans, device->FmtType, device->AmbiOrder);
+    self->Frequency = device->Frequency;
+    self->FmtChans = device->FmtChans;
+    self->FmtType = device->FmtType;
+    self->UpdateSize = device->UpdateSize;
+}
+
+static void ALCsdl2Backend_Destruct(ALCsdl2Backend *self)
+{
+    if(self->deviceID)
+        SDL_CloseAudioDevice(self->deviceID);
+    self->deviceID = 0;
+
+    ALCbackend_Destruct(STATIC_CAST(ALCbackend, self));
+    self->~ALCsdl2Backend();
+}
+
+
+static void ALCsdl2Backend_audioCallback(void *ptr, Uint8 *stream, int len)
+{
+    ALCsdl2Backend *self = static_cast<ALCsdl2Backend*>(ptr);
+    ALCdevice *device = STATIC_CAST(ALCbackend, self)->mDevice;
+
+    assert((len % self->frameSize) == 0);
+    aluMixData(device, stream, len / self->frameSize);
+}
+
+static ALCenum ALCsdl2Backend_open(ALCsdl2Backend *self, const ALCchar *name)
+{
+    ALCdevice *device = STATIC_CAST(ALCbackend, self)->mDevice;
+    SDL_AudioSpec want, have;
+
+    SDL_zero(want);
+    SDL_zero(have);
+
+    want.freq = device->Frequency;
+    switch(device->FmtType)
+    {
+        case DevFmtUByte: want.format = AUDIO_U8; break;
+        case DevFmtByte: want.format = AUDIO_S8; break;
+        case DevFmtUShort: want.format = AUDIO_U16SYS; break;
+        case DevFmtShort: want.format = AUDIO_S16SYS; break;
+        case DevFmtUInt: /* fall-through */
+        case DevFmtInt: want.format = AUDIO_S32SYS; break;
+        case DevFmtFloat: want.format = AUDIO_F32; break;
+    }
+    want.channels = (device->FmtChans == DevFmtMono) ? 1 : 2;
+    want.samples = device->UpdateSize;
+    want.callback = ALCsdl2Backend_audioCallback;
+    want.userdata = self;
+
+    /* Passing nullptr to SDL_OpenAudioDevice opens a default, which isn't
+     * necessarily the first in the list.
+     */
+    if(!name || strcmp(name, defaultDeviceName) == 0)
+        self->deviceID = SDL_OpenAudioDevice(nullptr, SDL_FALSE, &want, &have,
+                                             SDL_AUDIO_ALLOW_ANY_CHANGE);
+    else
+    {
+        const size_t prefix_len = strlen(DEVNAME_PREFIX);
+        if(strncmp(name, DEVNAME_PREFIX, prefix_len) == 0)
+            self->deviceID = SDL_OpenAudioDevice(name+prefix_len, SDL_FALSE, &want, &have,
+                                                 SDL_AUDIO_ALLOW_ANY_CHANGE);
+        else
+            self->deviceID = SDL_OpenAudioDevice(name, SDL_FALSE, &want, &have,
+                                                 SDL_AUDIO_ALLOW_ANY_CHANGE);
+    }
+    if(self->deviceID == 0)
+        return ALC_INVALID_VALUE;
+
+    device->Frequency = have.freq;
+    if(have.channels == 1)
+        device->FmtChans = DevFmtMono;
+    else if(have.channels == 2)
+        device->FmtChans = DevFmtStereo;
+    else
+    {
+        ERR("Got unhandled SDL channel count: %d\n", (int)have.channels);
+        return ALC_INVALID_VALUE;
+    }
+    switch(have.format)
+    {
+        case AUDIO_U8:     device->FmtType = DevFmtUByte;  break;
+        case AUDIO_S8:     device->FmtType = DevFmtByte;   break;
+        case AUDIO_U16SYS: device->FmtType = DevFmtUShort; break;
+        case AUDIO_S16SYS: device->FmtType = DevFmtShort;  break;
+        case AUDIO_S32SYS: device->FmtType = DevFmtInt;    break;
+        case AUDIO_F32SYS: device->FmtType = DevFmtFloat;  break;
+        default:
+            ERR("Got unsupported SDL format: 0x%04x\n", have.format);
+            return ALC_INVALID_VALUE;
+    }
+    device->UpdateSize = have.samples;
+    device->NumUpdates = 2; /* SDL always (tries to) use two periods. */
+
+    self->frameSize = FrameSizeFromDevFmt(device->FmtChans, device->FmtType, device->AmbiOrder);
+    self->Frequency = device->Frequency;
+    self->FmtChans = device->FmtChans;
+    self->FmtType = device->FmtType;
+    self->UpdateSize = device->UpdateSize;
+
+    alstr_copy_cstr(&device->DeviceName, name ? name : defaultDeviceName);
+
+    return ALC_NO_ERROR;
+}
+
+static ALCboolean ALCsdl2Backend_reset(ALCsdl2Backend *self)
+{
+    ALCdevice *device = STATIC_CAST(ALCbackend, self)->mDevice;
+    device->Frequency = self->Frequency;
+    device->FmtChans = self->FmtChans;
+    device->FmtType = self->FmtType;
+    device->UpdateSize = self->UpdateSize;
+    device->NumUpdates = 2;
+    SetDefaultWFXChannelOrder(device);
+    return ALC_TRUE;
+}
+
+static ALCboolean ALCsdl2Backend_start(ALCsdl2Backend *self)
+{
+    SDL_PauseAudioDevice(self->deviceID, 0);
+    return ALC_TRUE;
+}
+
+static void ALCsdl2Backend_stop(ALCsdl2Backend *self)
+{
+    SDL_PauseAudioDevice(self->deviceID, 1);
+}
+
+static void ALCsdl2Backend_lock(ALCsdl2Backend *self)
+{
+    SDL_LockAudioDevice(self->deviceID);
+}
+
+static void ALCsdl2Backend_unlock(ALCsdl2Backend *self)
+{
+    SDL_UnlockAudioDevice(self->deviceID);
+}
+
+
+struct ALCsdl2BackendFactory final : public ALCbackendFactory {
+    ALCsdl2BackendFactory() noexcept;
+};
+
+ALCbackendFactory *ALCsdl2BackendFactory_getFactory(void);
+
+static ALCboolean ALCsdl2BackendFactory_init(ALCsdl2BackendFactory *self);
+static void ALCsdl2BackendFactory_deinit(ALCsdl2BackendFactory *self);
+static ALCboolean ALCsdl2BackendFactory_querySupport(ALCsdl2BackendFactory *self, ALCbackend_Type type);
+static void ALCsdl2BackendFactory_probe(ALCsdl2BackendFactory *self, enum DevProbe type, al_string *outnames);
+static ALCbackend* ALCsdl2BackendFactory_createBackend(ALCsdl2BackendFactory *self, ALCdevice *device, ALCbackend_Type type);
+DEFINE_ALCBACKENDFACTORY_VTABLE(ALCsdl2BackendFactory);
+
+
+ALCsdl2BackendFactory::ALCsdl2BackendFactory() noexcept
+  : ALCbackendFactory{GET_VTABLE2(ALCsdl2BackendFactory, ALCbackendFactory)}
+{ }
+
+ALCbackendFactory *ALCsdl2BackendFactory_getFactory(void)
+{
+    static ALCsdl2BackendFactory factory{};
+    return STATIC_CAST(ALCbackendFactory, &factory);
+}
+
+
+static ALCboolean ALCsdl2BackendFactory_init(ALCsdl2BackendFactory* UNUSED(self))
+{
+    if(SDL_InitSubSystem(SDL_INIT_AUDIO) == 0)
+        return AL_TRUE;
+    return ALC_FALSE;
+}
+
+static void ALCsdl2BackendFactory_deinit(ALCsdl2BackendFactory* UNUSED(self))
+{
+    SDL_QuitSubSystem(SDL_INIT_AUDIO);
+}
+
+static ALCboolean ALCsdl2BackendFactory_querySupport(ALCsdl2BackendFactory* UNUSED(self), ALCbackend_Type type)
+{
+    if(type == ALCbackend_Playback)
+        return ALC_TRUE;
+    return ALC_FALSE;
+}
+
+static void ALCsdl2BackendFactory_probe(ALCsdl2BackendFactory* UNUSED(self), enum DevProbe type, al_string *outnames)
+{
+    if(type != ALL_DEVICE_PROBE)
+        return;
+
+    int num_devices{SDL_GetNumAudioDevices(SDL_FALSE)};
+
+    alstr_append_range(outnames, defaultDeviceName, defaultDeviceName+sizeof(defaultDeviceName));
+    for(int i{0};i < num_devices;++i)
+    {
+        std::string name{DEVNAME_PREFIX};
+        name += SDL_GetAudioDeviceName(i, SDL_FALSE);
+        if(!name.empty())
+        {
+            const char *namestr{name.c_str()};
+            alstr_append_range(outnames, namestr, namestr+name.length()+1);
+        }
+    }
+}
+
+static ALCbackend* ALCsdl2BackendFactory_createBackend(ALCsdl2BackendFactory* UNUSED(self), ALCdevice *device, ALCbackend_Type type)
+{
+    if(type == ALCbackend_Playback)
+    {
+        ALCsdl2Backend *backend;
+        NEW_OBJ(backend, ALCsdl2Backend)(device);
+        if(!backend) return nullptr;
+        return STATIC_CAST(ALCbackend, backend);
+    }
+
+    return nullptr;
+}