/**
 * OpenAL cross platform audio library
 * Copyright (C) 1999-2007 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 "version.h"

#include <stdlib.h>
#include <stdio.h>
#include <memory.h>
#include <ctype.h>
#include <signal.h>

#include <cmath>
#include <atomic>
#include <mutex>
#include <thread>
#include <vector>
#include <string>
#include <algorithm>

#include "alMain.h"
#include "alcontext.h"
#include "alSource.h"
#include "alListener.h"
#include "alSource.h"
#include "alBuffer.h"
#include "alFilter.h"
#include "alEffect.h"
#include "alAuxEffectSlot.h"
#include "alError.h"
#include "mastering.h"
#include "bformatdec.h"
#include "alu.h"
#include "alconfig.h"
#include "ringbuffer.h"

#include "fpu_modes.h"
#include "cpu_caps.h"
#include "compat.h"
#include "threads.h"
#include "almalloc.h"

#include "backends/base.h"
#include "backends/null.h"
#include "backends/loopback.h"
#ifdef HAVE_JACK
#include "backends/jack.h"
#endif
#ifdef HAVE_PULSEAUDIO
#include "backends/pulseaudio.h"
#endif
#ifdef HAVE_ALSA
#include "backends/alsa.h"
#endif
#ifdef HAVE_WASAPI
#include "backends/wasapi.h"
#endif
#ifdef HAVE_COREAUDIO
#include "backends/coreaudio.h"
#endif
#ifdef HAVE_OPENSL
#include "backends/opensl.h"
#endif
#ifdef HAVE_SOLARIS
#include "backends/solaris.h"
#endif
#ifdef HAVE_SNDIO
#include "backends/sndio.h"
#endif
#ifdef HAVE_OSS
#include "backends/oss.h"
#endif
#ifdef HAVE_QSA
#include "backends/qsa.h"
#endif
#ifdef HAVE_DSOUND
#include "backends/dsound.h"
#endif
#ifdef HAVE_WINMM
#include "backends/winmm.h"
#endif
#ifdef HAVE_PORTAUDIO
#include "backends/portaudio.h"
#endif
#ifdef HAVE_SDL2
#include "backends/sdl2.h"
#endif
#ifdef HAVE_WAVE
#include "backends/wave.h"
#endif


namespace {

/************************************************
 * Backends
 ************************************************/
struct BackendInfo {
    const char *name;
    BackendFactory& (*getFactory)(void);
};

struct BackendInfo BackendList[] = {
#ifdef HAVE_JACK
    { "jack", JackBackendFactory::getFactory },
#endif
#ifdef HAVE_PULSEAUDIO
    { "pulse", PulseBackendFactory::getFactory },
#endif
#ifdef HAVE_ALSA
    { "alsa", AlsaBackendFactory::getFactory },
#endif
#ifdef HAVE_WASAPI
    { "wasapi", WasapiBackendFactory::getFactory },
#endif
#ifdef HAVE_COREAUDIO
    { "core", CoreAudioBackendFactory::getFactory },
#endif
#ifdef HAVE_OPENSL
    { "opensl", OSLBackendFactory::getFactory },
#endif
#ifdef HAVE_SOLARIS
    { "solaris", SolarisBackendFactory::getFactory },
#endif
#ifdef HAVE_SNDIO
    { "sndio", SndIOBackendFactory::getFactory },
#endif
#ifdef HAVE_OSS
    { "oss", OSSBackendFactory::getFactory },
#endif
#ifdef HAVE_QSA
    { "qsa", QSABackendFactory::getFactory },
#endif
#ifdef HAVE_DSOUND
    { "dsound", DSoundBackendFactory::getFactory },
#endif
#ifdef HAVE_WINMM
    { "winmm", WinMMBackendFactory::getFactory },
#endif
#ifdef HAVE_PORTAUDIO
    { "port", PortBackendFactory::getFactory },
#endif
#ifdef HAVE_SDL2
    { "sdl2", SDL2BackendFactory::getFactory },
#endif

    { "null", NullBackendFactory::getFactory },
#ifdef HAVE_WAVE
    { "wave", WaveBackendFactory::getFactory },
#endif
};
ALsizei BackendListSize = COUNTOF(BackendList);

struct BackendInfo PlaybackBackend;
struct BackendInfo CaptureBackend;


/************************************************
 * Functions, enums, and errors
 ************************************************/
#define DECL(x) { #x, (ALCvoid*)(x) }
constexpr struct {
    const ALCchar *funcName;
    ALCvoid *address;
} alcFunctions[] = {
    DECL(alcCreateContext),
    DECL(alcMakeContextCurrent),
    DECL(alcProcessContext),
    DECL(alcSuspendContext),
    DECL(alcDestroyContext),
    DECL(alcGetCurrentContext),
    DECL(alcGetContextsDevice),
    DECL(alcOpenDevice),
    DECL(alcCloseDevice),
    DECL(alcGetError),
    DECL(alcIsExtensionPresent),
    DECL(alcGetProcAddress),
    DECL(alcGetEnumValue),
    DECL(alcGetString),
    DECL(alcGetIntegerv),
    DECL(alcCaptureOpenDevice),
    DECL(alcCaptureCloseDevice),
    DECL(alcCaptureStart),
    DECL(alcCaptureStop),
    DECL(alcCaptureSamples),

    DECL(alcSetThreadContext),
    DECL(alcGetThreadContext),

    DECL(alcLoopbackOpenDeviceSOFT),
    DECL(alcIsRenderFormatSupportedSOFT),
    DECL(alcRenderSamplesSOFT),

    DECL(alcDevicePauseSOFT),
    DECL(alcDeviceResumeSOFT),

    DECL(alcGetStringiSOFT),
    DECL(alcResetDeviceSOFT),

    DECL(alcGetInteger64vSOFT),

    DECL(alEnable),
    DECL(alDisable),
    DECL(alIsEnabled),
    DECL(alGetString),
    DECL(alGetBooleanv),
    DECL(alGetIntegerv),
    DECL(alGetFloatv),
    DECL(alGetDoublev),
    DECL(alGetBoolean),
    DECL(alGetInteger),
    DECL(alGetFloat),
    DECL(alGetDouble),
    DECL(alGetError),
    DECL(alIsExtensionPresent),
    DECL(alGetProcAddress),
    DECL(alGetEnumValue),
    DECL(alListenerf),
    DECL(alListener3f),
    DECL(alListenerfv),
    DECL(alListeneri),
    DECL(alListener3i),
    DECL(alListeneriv),
    DECL(alGetListenerf),
    DECL(alGetListener3f),
    DECL(alGetListenerfv),
    DECL(alGetListeneri),
    DECL(alGetListener3i),
    DECL(alGetListeneriv),
    DECL(alGenSources),
    DECL(alDeleteSources),
    DECL(alIsSource),
    DECL(alSourcef),
    DECL(alSource3f),
    DECL(alSourcefv),
    DECL(alSourcei),
    DECL(alSource3i),
    DECL(alSourceiv),
    DECL(alGetSourcef),
    DECL(alGetSource3f),
    DECL(alGetSourcefv),
    DECL(alGetSourcei),
    DECL(alGetSource3i),
    DECL(alGetSourceiv),
    DECL(alSourcePlayv),
    DECL(alSourceStopv),
    DECL(alSourceRewindv),
    DECL(alSourcePausev),
    DECL(alSourcePlay),
    DECL(alSourceStop),
    DECL(alSourceRewind),
    DECL(alSourcePause),
    DECL(alSourceQueueBuffers),
    DECL(alSourceUnqueueBuffers),
    DECL(alGenBuffers),
    DECL(alDeleteBuffers),
    DECL(alIsBuffer),
    DECL(alBufferData),
    DECL(alBufferf),
    DECL(alBuffer3f),
    DECL(alBufferfv),
    DECL(alBufferi),
    DECL(alBuffer3i),
    DECL(alBufferiv),
    DECL(alGetBufferf),
    DECL(alGetBuffer3f),
    DECL(alGetBufferfv),
    DECL(alGetBufferi),
    DECL(alGetBuffer3i),
    DECL(alGetBufferiv),
    DECL(alDopplerFactor),
    DECL(alDopplerVelocity),
    DECL(alSpeedOfSound),
    DECL(alDistanceModel),

    DECL(alGenFilters),
    DECL(alDeleteFilters),
    DECL(alIsFilter),
    DECL(alFilteri),
    DECL(alFilteriv),
    DECL(alFilterf),
    DECL(alFilterfv),
    DECL(alGetFilteri),
    DECL(alGetFilteriv),
    DECL(alGetFilterf),
    DECL(alGetFilterfv),
    DECL(alGenEffects),
    DECL(alDeleteEffects),
    DECL(alIsEffect),
    DECL(alEffecti),
    DECL(alEffectiv),
    DECL(alEffectf),
    DECL(alEffectfv),
    DECL(alGetEffecti),
    DECL(alGetEffectiv),
    DECL(alGetEffectf),
    DECL(alGetEffectfv),
    DECL(alGenAuxiliaryEffectSlots),
    DECL(alDeleteAuxiliaryEffectSlots),
    DECL(alIsAuxiliaryEffectSlot),
    DECL(alAuxiliaryEffectSloti),
    DECL(alAuxiliaryEffectSlotiv),
    DECL(alAuxiliaryEffectSlotf),
    DECL(alAuxiliaryEffectSlotfv),
    DECL(alGetAuxiliaryEffectSloti),
    DECL(alGetAuxiliaryEffectSlotiv),
    DECL(alGetAuxiliaryEffectSlotf),
    DECL(alGetAuxiliaryEffectSlotfv),

    DECL(alDeferUpdatesSOFT),
    DECL(alProcessUpdatesSOFT),

    DECL(alSourcedSOFT),
    DECL(alSource3dSOFT),
    DECL(alSourcedvSOFT),
    DECL(alGetSourcedSOFT),
    DECL(alGetSource3dSOFT),
    DECL(alGetSourcedvSOFT),
    DECL(alSourcei64SOFT),
    DECL(alSource3i64SOFT),
    DECL(alSourcei64vSOFT),
    DECL(alGetSourcei64SOFT),
    DECL(alGetSource3i64SOFT),
    DECL(alGetSourcei64vSOFT),

    DECL(alGetStringiSOFT),

    DECL(alBufferStorageSOFT),
    DECL(alMapBufferSOFT),
    DECL(alUnmapBufferSOFT),
    DECL(alFlushMappedBufferSOFT),

    DECL(alEventControlSOFT),
    DECL(alEventCallbackSOFT),
    DECL(alGetPointerSOFT),
    DECL(alGetPointervSOFT),
};
#undef DECL

#define DECL(x) { #x, (x) }
constexpr struct {
    const ALCchar *enumName;
    ALCenum value;
} alcEnumerations[] = {
    DECL(ALC_INVALID),
    DECL(ALC_FALSE),
    DECL(ALC_TRUE),

    DECL(ALC_MAJOR_VERSION),
    DECL(ALC_MINOR_VERSION),
    DECL(ALC_ATTRIBUTES_SIZE),
    DECL(ALC_ALL_ATTRIBUTES),
    DECL(ALC_DEFAULT_DEVICE_SPECIFIER),
    DECL(ALC_DEVICE_SPECIFIER),
    DECL(ALC_ALL_DEVICES_SPECIFIER),
    DECL(ALC_DEFAULT_ALL_DEVICES_SPECIFIER),
    DECL(ALC_EXTENSIONS),
    DECL(ALC_FREQUENCY),
    DECL(ALC_REFRESH),
    DECL(ALC_SYNC),
    DECL(ALC_MONO_SOURCES),
    DECL(ALC_STEREO_SOURCES),
    DECL(ALC_CAPTURE_DEVICE_SPECIFIER),
    DECL(ALC_CAPTURE_DEFAULT_DEVICE_SPECIFIER),
    DECL(ALC_CAPTURE_SAMPLES),
    DECL(ALC_CONNECTED),

    DECL(ALC_EFX_MAJOR_VERSION),
    DECL(ALC_EFX_MINOR_VERSION),
    DECL(ALC_MAX_AUXILIARY_SENDS),

    DECL(ALC_FORMAT_CHANNELS_SOFT),
    DECL(ALC_FORMAT_TYPE_SOFT),

    DECL(ALC_MONO_SOFT),
    DECL(ALC_STEREO_SOFT),
    DECL(ALC_QUAD_SOFT),
    DECL(ALC_5POINT1_SOFT),
    DECL(ALC_6POINT1_SOFT),
    DECL(ALC_7POINT1_SOFT),
    DECL(ALC_BFORMAT3D_SOFT),

    DECL(ALC_BYTE_SOFT),
    DECL(ALC_UNSIGNED_BYTE_SOFT),
    DECL(ALC_SHORT_SOFT),
    DECL(ALC_UNSIGNED_SHORT_SOFT),
    DECL(ALC_INT_SOFT),
    DECL(ALC_UNSIGNED_INT_SOFT),
    DECL(ALC_FLOAT_SOFT),

    DECL(ALC_HRTF_SOFT),
    DECL(ALC_DONT_CARE_SOFT),
    DECL(ALC_HRTF_STATUS_SOFT),
    DECL(ALC_HRTF_DISABLED_SOFT),
    DECL(ALC_HRTF_ENABLED_SOFT),
    DECL(ALC_HRTF_DENIED_SOFT),
    DECL(ALC_HRTF_REQUIRED_SOFT),
    DECL(ALC_HRTF_HEADPHONES_DETECTED_SOFT),
    DECL(ALC_HRTF_UNSUPPORTED_FORMAT_SOFT),
    DECL(ALC_NUM_HRTF_SPECIFIERS_SOFT),
    DECL(ALC_HRTF_SPECIFIER_SOFT),
    DECL(ALC_HRTF_ID_SOFT),

    DECL(ALC_AMBISONIC_LAYOUT_SOFT),
    DECL(ALC_AMBISONIC_SCALING_SOFT),
    DECL(ALC_AMBISONIC_ORDER_SOFT),
    DECL(ALC_ACN_SOFT),
    DECL(ALC_FUMA_SOFT),
    DECL(ALC_N3D_SOFT),
    DECL(ALC_SN3D_SOFT),

    DECL(ALC_OUTPUT_LIMITER_SOFT),

    DECL(ALC_NO_ERROR),
    DECL(ALC_INVALID_DEVICE),
    DECL(ALC_INVALID_CONTEXT),
    DECL(ALC_INVALID_ENUM),
    DECL(ALC_INVALID_VALUE),
    DECL(ALC_OUT_OF_MEMORY),


    DECL(AL_INVALID),
    DECL(AL_NONE),
    DECL(AL_FALSE),
    DECL(AL_TRUE),

    DECL(AL_SOURCE_RELATIVE),
    DECL(AL_CONE_INNER_ANGLE),
    DECL(AL_CONE_OUTER_ANGLE),
    DECL(AL_PITCH),
    DECL(AL_POSITION),
    DECL(AL_DIRECTION),
    DECL(AL_VELOCITY),
    DECL(AL_LOOPING),
    DECL(AL_BUFFER),
    DECL(AL_GAIN),
    DECL(AL_MIN_GAIN),
    DECL(AL_MAX_GAIN),
    DECL(AL_ORIENTATION),
    DECL(AL_REFERENCE_DISTANCE),
    DECL(AL_ROLLOFF_FACTOR),
    DECL(AL_CONE_OUTER_GAIN),
    DECL(AL_MAX_DISTANCE),
    DECL(AL_SEC_OFFSET),
    DECL(AL_SAMPLE_OFFSET),
    DECL(AL_BYTE_OFFSET),
    DECL(AL_SOURCE_TYPE),
    DECL(AL_STATIC),
    DECL(AL_STREAMING),
    DECL(AL_UNDETERMINED),
    DECL(AL_METERS_PER_UNIT),
    DECL(AL_LOOP_POINTS_SOFT),
    DECL(AL_DIRECT_CHANNELS_SOFT),

    DECL(AL_DIRECT_FILTER),
    DECL(AL_AUXILIARY_SEND_FILTER),
    DECL(AL_AIR_ABSORPTION_FACTOR),
    DECL(AL_ROOM_ROLLOFF_FACTOR),
    DECL(AL_CONE_OUTER_GAINHF),
    DECL(AL_DIRECT_FILTER_GAINHF_AUTO),
    DECL(AL_AUXILIARY_SEND_FILTER_GAIN_AUTO),
    DECL(AL_AUXILIARY_SEND_FILTER_GAINHF_AUTO),

    DECL(AL_SOURCE_STATE),
    DECL(AL_INITIAL),
    DECL(AL_PLAYING),
    DECL(AL_PAUSED),
    DECL(AL_STOPPED),

    DECL(AL_BUFFERS_QUEUED),
    DECL(AL_BUFFERS_PROCESSED),

    DECL(AL_FORMAT_MONO8),
    DECL(AL_FORMAT_MONO16),
    DECL(AL_FORMAT_MONO_FLOAT32),
    DECL(AL_FORMAT_MONO_DOUBLE_EXT),
    DECL(AL_FORMAT_STEREO8),
    DECL(AL_FORMAT_STEREO16),
    DECL(AL_FORMAT_STEREO_FLOAT32),
    DECL(AL_FORMAT_STEREO_DOUBLE_EXT),
    DECL(AL_FORMAT_MONO_IMA4),
    DECL(AL_FORMAT_STEREO_IMA4),
    DECL(AL_FORMAT_MONO_MSADPCM_SOFT),
    DECL(AL_FORMAT_STEREO_MSADPCM_SOFT),
    DECL(AL_FORMAT_QUAD8_LOKI),
    DECL(AL_FORMAT_QUAD16_LOKI),
    DECL(AL_FORMAT_QUAD8),
    DECL(AL_FORMAT_QUAD16),
    DECL(AL_FORMAT_QUAD32),
    DECL(AL_FORMAT_51CHN8),
    DECL(AL_FORMAT_51CHN16),
    DECL(AL_FORMAT_51CHN32),
    DECL(AL_FORMAT_61CHN8),
    DECL(AL_FORMAT_61CHN16),
    DECL(AL_FORMAT_61CHN32),
    DECL(AL_FORMAT_71CHN8),
    DECL(AL_FORMAT_71CHN16),
    DECL(AL_FORMAT_71CHN32),
    DECL(AL_FORMAT_REAR8),
    DECL(AL_FORMAT_REAR16),
    DECL(AL_FORMAT_REAR32),
    DECL(AL_FORMAT_MONO_MULAW),
    DECL(AL_FORMAT_MONO_MULAW_EXT),
    DECL(AL_FORMAT_STEREO_MULAW),
    DECL(AL_FORMAT_STEREO_MULAW_EXT),
    DECL(AL_FORMAT_QUAD_MULAW),
    DECL(AL_FORMAT_51CHN_MULAW),
    DECL(AL_FORMAT_61CHN_MULAW),
    DECL(AL_FORMAT_71CHN_MULAW),
    DECL(AL_FORMAT_REAR_MULAW),
    DECL(AL_FORMAT_MONO_ALAW_EXT),
    DECL(AL_FORMAT_STEREO_ALAW_EXT),

    DECL(AL_FORMAT_BFORMAT2D_8),
    DECL(AL_FORMAT_BFORMAT2D_16),
    DECL(AL_FORMAT_BFORMAT2D_FLOAT32),
    DECL(AL_FORMAT_BFORMAT2D_MULAW),
    DECL(AL_FORMAT_BFORMAT3D_8),
    DECL(AL_FORMAT_BFORMAT3D_16),
    DECL(AL_FORMAT_BFORMAT3D_FLOAT32),
    DECL(AL_FORMAT_BFORMAT3D_MULAW),

    DECL(AL_FREQUENCY),
    DECL(AL_BITS),
    DECL(AL_CHANNELS),
    DECL(AL_SIZE),
    DECL(AL_UNPACK_BLOCK_ALIGNMENT_SOFT),
    DECL(AL_PACK_BLOCK_ALIGNMENT_SOFT),

    DECL(AL_SOURCE_RADIUS),

    DECL(AL_STEREO_ANGLES),

    DECL(AL_UNUSED),
    DECL(AL_PENDING),
    DECL(AL_PROCESSED),

    DECL(AL_NO_ERROR),
    DECL(AL_INVALID_NAME),
    DECL(AL_INVALID_ENUM),
    DECL(AL_INVALID_VALUE),
    DECL(AL_INVALID_OPERATION),
    DECL(AL_OUT_OF_MEMORY),

    DECL(AL_VENDOR),
    DECL(AL_VERSION),
    DECL(AL_RENDERER),
    DECL(AL_EXTENSIONS),

    DECL(AL_DOPPLER_FACTOR),
    DECL(AL_DOPPLER_VELOCITY),
    DECL(AL_DISTANCE_MODEL),
    DECL(AL_SPEED_OF_SOUND),
    DECL(AL_SOURCE_DISTANCE_MODEL),
    DECL(AL_DEFERRED_UPDATES_SOFT),
    DECL(AL_GAIN_LIMIT_SOFT),

    DECL(AL_INVERSE_DISTANCE),
    DECL(AL_INVERSE_DISTANCE_CLAMPED),
    DECL(AL_LINEAR_DISTANCE),
    DECL(AL_LINEAR_DISTANCE_CLAMPED),
    DECL(AL_EXPONENT_DISTANCE),
    DECL(AL_EXPONENT_DISTANCE_CLAMPED),

    DECL(AL_FILTER_TYPE),
    DECL(AL_FILTER_NULL),
    DECL(AL_FILTER_LOWPASS),
    DECL(AL_FILTER_HIGHPASS),
    DECL(AL_FILTER_BANDPASS),

    DECL(AL_LOWPASS_GAIN),
    DECL(AL_LOWPASS_GAINHF),

    DECL(AL_HIGHPASS_GAIN),
    DECL(AL_HIGHPASS_GAINLF),

    DECL(AL_BANDPASS_GAIN),
    DECL(AL_BANDPASS_GAINHF),
    DECL(AL_BANDPASS_GAINLF),

    DECL(AL_EFFECT_TYPE),
    DECL(AL_EFFECT_NULL),
    DECL(AL_EFFECT_REVERB),
    DECL(AL_EFFECT_EAXREVERB),
    DECL(AL_EFFECT_CHORUS),
    DECL(AL_EFFECT_DISTORTION),
    DECL(AL_EFFECT_ECHO),
    DECL(AL_EFFECT_FLANGER),
    DECL(AL_EFFECT_PITCH_SHIFTER),
    DECL(AL_EFFECT_FREQUENCY_SHIFTER),
#if 0
    DECL(AL_EFFECT_VOCAL_MORPHER),
#endif
    DECL(AL_EFFECT_RING_MODULATOR),
    DECL(AL_EFFECT_AUTOWAH),
    DECL(AL_EFFECT_COMPRESSOR),
    DECL(AL_EFFECT_EQUALIZER),
    DECL(AL_EFFECT_DEDICATED_LOW_FREQUENCY_EFFECT),
    DECL(AL_EFFECT_DEDICATED_DIALOGUE),

    DECL(AL_EFFECTSLOT_EFFECT),
    DECL(AL_EFFECTSLOT_GAIN),
    DECL(AL_EFFECTSLOT_AUXILIARY_SEND_AUTO),
    DECL(AL_EFFECTSLOT_NULL),

    DECL(AL_EAXREVERB_DENSITY),
    DECL(AL_EAXREVERB_DIFFUSION),
    DECL(AL_EAXREVERB_GAIN),
    DECL(AL_EAXREVERB_GAINHF),
    DECL(AL_EAXREVERB_GAINLF),
    DECL(AL_EAXREVERB_DECAY_TIME),
    DECL(AL_EAXREVERB_DECAY_HFRATIO),
    DECL(AL_EAXREVERB_DECAY_LFRATIO),
    DECL(AL_EAXREVERB_REFLECTIONS_GAIN),
    DECL(AL_EAXREVERB_REFLECTIONS_DELAY),
    DECL(AL_EAXREVERB_REFLECTIONS_PAN),
    DECL(AL_EAXREVERB_LATE_REVERB_GAIN),
    DECL(AL_EAXREVERB_LATE_REVERB_DELAY),
    DECL(AL_EAXREVERB_LATE_REVERB_PAN),
    DECL(AL_EAXREVERB_ECHO_TIME),
    DECL(AL_EAXREVERB_ECHO_DEPTH),
    DECL(AL_EAXREVERB_MODULATION_TIME),
    DECL(AL_EAXREVERB_MODULATION_DEPTH),
    DECL(AL_EAXREVERB_AIR_ABSORPTION_GAINHF),
    DECL(AL_EAXREVERB_HFREFERENCE),
    DECL(AL_EAXREVERB_LFREFERENCE),
    DECL(AL_EAXREVERB_ROOM_ROLLOFF_FACTOR),
    DECL(AL_EAXREVERB_DECAY_HFLIMIT),

    DECL(AL_REVERB_DENSITY),
    DECL(AL_REVERB_DIFFUSION),
    DECL(AL_REVERB_GAIN),
    DECL(AL_REVERB_GAINHF),
    DECL(AL_REVERB_DECAY_TIME),
    DECL(AL_REVERB_DECAY_HFRATIO),
    DECL(AL_REVERB_REFLECTIONS_GAIN),
    DECL(AL_REVERB_REFLECTIONS_DELAY),
    DECL(AL_REVERB_LATE_REVERB_GAIN),
    DECL(AL_REVERB_LATE_REVERB_DELAY),
    DECL(AL_REVERB_AIR_ABSORPTION_GAINHF),
    DECL(AL_REVERB_ROOM_ROLLOFF_FACTOR),
    DECL(AL_REVERB_DECAY_HFLIMIT),

    DECL(AL_CHORUS_WAVEFORM),
    DECL(AL_CHORUS_PHASE),
    DECL(AL_CHORUS_RATE),
    DECL(AL_CHORUS_DEPTH),
    DECL(AL_CHORUS_FEEDBACK),
    DECL(AL_CHORUS_DELAY),

    DECL(AL_DISTORTION_EDGE),
    DECL(AL_DISTORTION_GAIN),
    DECL(AL_DISTORTION_LOWPASS_CUTOFF),
    DECL(AL_DISTORTION_EQCENTER),
    DECL(AL_DISTORTION_EQBANDWIDTH),

    DECL(AL_ECHO_DELAY),
    DECL(AL_ECHO_LRDELAY),
    DECL(AL_ECHO_DAMPING),
    DECL(AL_ECHO_FEEDBACK),
    DECL(AL_ECHO_SPREAD),

    DECL(AL_FLANGER_WAVEFORM),
    DECL(AL_FLANGER_PHASE),
    DECL(AL_FLANGER_RATE),
    DECL(AL_FLANGER_DEPTH),
    DECL(AL_FLANGER_FEEDBACK),
    DECL(AL_FLANGER_DELAY),

    DECL(AL_FREQUENCY_SHIFTER_FREQUENCY),
    DECL(AL_FREQUENCY_SHIFTER_LEFT_DIRECTION),
    DECL(AL_FREQUENCY_SHIFTER_RIGHT_DIRECTION),

    DECL(AL_RING_MODULATOR_FREQUENCY),
    DECL(AL_RING_MODULATOR_HIGHPASS_CUTOFF),
    DECL(AL_RING_MODULATOR_WAVEFORM),

    DECL(AL_PITCH_SHIFTER_COARSE_TUNE),
    DECL(AL_PITCH_SHIFTER_FINE_TUNE),

    DECL(AL_COMPRESSOR_ONOFF),

    DECL(AL_EQUALIZER_LOW_GAIN),
    DECL(AL_EQUALIZER_LOW_CUTOFF),
    DECL(AL_EQUALIZER_MID1_GAIN),
    DECL(AL_EQUALIZER_MID1_CENTER),
    DECL(AL_EQUALIZER_MID1_WIDTH),
    DECL(AL_EQUALIZER_MID2_GAIN),
    DECL(AL_EQUALIZER_MID2_CENTER),
    DECL(AL_EQUALIZER_MID2_WIDTH),
    DECL(AL_EQUALIZER_HIGH_GAIN),
    DECL(AL_EQUALIZER_HIGH_CUTOFF),

    DECL(AL_DEDICATED_GAIN),

    DECL(AL_AUTOWAH_ATTACK_TIME),
    DECL(AL_AUTOWAH_RELEASE_TIME),
    DECL(AL_AUTOWAH_RESONANCE),
    DECL(AL_AUTOWAH_PEAK_GAIN),

    DECL(AL_NUM_RESAMPLERS_SOFT),
    DECL(AL_DEFAULT_RESAMPLER_SOFT),
    DECL(AL_SOURCE_RESAMPLER_SOFT),
    DECL(AL_RESAMPLER_NAME_SOFT),

    DECL(AL_SOURCE_SPATIALIZE_SOFT),
    DECL(AL_AUTO_SOFT),

    DECL(AL_MAP_READ_BIT_SOFT),
    DECL(AL_MAP_WRITE_BIT_SOFT),
    DECL(AL_MAP_PERSISTENT_BIT_SOFT),
    DECL(AL_PRESERVE_DATA_BIT_SOFT),

    DECL(AL_EVENT_CALLBACK_FUNCTION_SOFT),
    DECL(AL_EVENT_CALLBACK_USER_PARAM_SOFT),
    DECL(AL_EVENT_TYPE_BUFFER_COMPLETED_SOFT),
    DECL(AL_EVENT_TYPE_SOURCE_STATE_CHANGED_SOFT),
    DECL(AL_EVENT_TYPE_ERROR_SOFT),
    DECL(AL_EVENT_TYPE_PERFORMANCE_SOFT),
    DECL(AL_EVENT_TYPE_DEPRECATED_SOFT),
};
#undef DECL

constexpr ALCchar alcNoError[] = "No Error";
constexpr ALCchar alcErrInvalidDevice[] = "Invalid Device";
constexpr ALCchar alcErrInvalidContext[] = "Invalid Context";
constexpr ALCchar alcErrInvalidEnum[] = "Invalid Enum";
constexpr ALCchar alcErrInvalidValue[] = "Invalid Value";
constexpr ALCchar alcErrOutOfMemory[] = "Out of Memory";


/************************************************
 * Global variables
 ************************************************/

/* Enumerated device names */
constexpr ALCchar alcDefaultName[] = "OpenAL Soft\0";

std::string alcAllDevicesList;
std::string alcCaptureDeviceList;

/* Default is always the first in the list */
std::string alcDefaultAllDevicesSpecifier;
std::string alcCaptureDefaultDeviceSpecifier;

/* Default context extensions */
constexpr ALchar alExtList[] =
    "AL_EXT_ALAW "
    "AL_EXT_BFORMAT "
    "AL_EXT_DOUBLE "
    "AL_EXT_EXPONENT_DISTANCE "
    "AL_EXT_FLOAT32 "
    "AL_EXT_IMA4 "
    "AL_EXT_LINEAR_DISTANCE "
    "AL_EXT_MCFORMATS "
    "AL_EXT_MULAW "
    "AL_EXT_MULAW_BFORMAT "
    "AL_EXT_MULAW_MCFORMATS "
    "AL_EXT_OFFSET "
    "AL_EXT_source_distance_model "
    "AL_EXT_SOURCE_RADIUS "
    "AL_EXT_STEREO_ANGLES "
    "AL_LOKI_quadriphonic "
    "AL_SOFT_block_alignment "
    "AL_SOFT_deferred_updates "
    "AL_SOFT_direct_channels "
    "AL_SOFTX_events "
    "AL_SOFTX_filter_gain_ex "
    "AL_SOFT_gain_clamp_ex "
    "AL_SOFT_loop_points "
    "AL_SOFTX_map_buffer "
    "AL_SOFT_MSADPCM "
    "AL_SOFT_source_latency "
    "AL_SOFT_source_length "
    "AL_SOFT_source_resampler "
    "AL_SOFT_source_spatialize";

std::atomic<ALCenum> LastNullDeviceError{ALC_NO_ERROR};

/* Thread-local current context */
std::atomic<void(*)(ALCcontext*)> ThreadCtxProc{nullptr};
class ThreadCtx {
    ALCcontext *ctx{nullptr};

public:
    ~ThreadCtx()
    {
        auto destruct = ThreadCtxProc.load();
        if(destruct && ctx)
            destruct(ctx);
        ctx = nullptr;
    }

    ALCcontext *get() const noexcept { return ctx; }
    void set(ALCcontext *ctx_) noexcept { ctx = ctx_; }
};
thread_local ThreadCtx LocalContext;
/* Process-wide current context */
std::atomic<ALCcontext*> GlobalContext{nullptr};

/* Flag to trap ALC device errors */
bool TrapALCError{false};

/* One-time configuration init control */
std::once_flag alc_config_once{};

/* Default effect that applies to sources that don't have an effect on send 0 */
ALeffect DefaultEffect;

/* Flag to specify if alcSuspendContext/alcProcessContext should defer/process
 * updates.
 */
bool SuspendDefers{true};


/************************************************
 * ALC information
 ************************************************/
constexpr ALCchar alcNoDeviceExtList[] =
    "ALC_ENUMERATE_ALL_EXT ALC_ENUMERATION_EXT ALC_EXT_CAPTURE "
    "ALC_EXT_thread_local_context ALC_SOFT_loopback";
constexpr ALCchar alcExtensionList[] =
    "ALC_ENUMERATE_ALL_EXT ALC_ENUMERATION_EXT ALC_EXT_CAPTURE "
    "ALC_EXT_DEDICATED ALC_EXT_disconnect ALC_EXT_EFX "
    "ALC_EXT_thread_local_context ALC_SOFT_device_clock ALC_SOFT_HRTF "
    "ALC_SOFT_loopback ALC_SOFT_output_limiter ALC_SOFT_pause_device";
constexpr ALCint alcMajorVersion = 1;
constexpr ALCint alcMinorVersion = 1;

constexpr ALCint alcEFXMajorVersion = 1;
constexpr ALCint alcEFXMinorVersion = 0;


/************************************************
 * Device lists
 ************************************************/
std::atomic<ALCdevice*> DeviceList{nullptr};

std::recursive_mutex ListLock;

} // namespace

/* Mixing thread piority level */
ALint RTPrioLevel;

FILE *LogFile;
#ifdef _DEBUG
enum LogLevel LogLevel = LogWarning;
#else
enum LogLevel LogLevel = LogError;
#endif

/************************************************
 * Library initialization
 ************************************************/
#if defined(_WIN32)
static void alc_init(void);
static void alc_deinit(void);
static void alc_deinit_safe(void);

#ifndef AL_LIBTYPE_STATIC
BOOL APIENTRY DllMain(HINSTANCE hModule, DWORD reason, LPVOID lpReserved)
{
    switch(reason)
    {
        case DLL_PROCESS_ATTACH:
            /* Pin the DLL so we won't get unloaded until the process terminates */
            GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_PIN | GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
                               (WCHAR*)hModule, &hModule);
            alc_init();
            break;

        case DLL_PROCESS_DETACH:
            if(!lpReserved)
                alc_deinit();
            else
                alc_deinit_safe();
            break;
    }
    return TRUE;
}
#elif defined(_MSC_VER)
#pragma section(".CRT$XCU",read)
static void alc_constructor(void);
static void alc_destructor(void);
__declspec(allocate(".CRT$XCU")) void (__cdecl* alc_constructor_)(void) = alc_constructor;

static void alc_constructor(void)
{
    atexit(alc_destructor);
    alc_init();
}

static void alc_destructor(void)
{
    alc_deinit();
}
#elif defined(HAVE_GCC_DESTRUCTOR)
static void alc_init(void) __attribute__((constructor));
static void alc_deinit(void) __attribute__((destructor));
#else
#error "No static initialization available on this platform!"
#endif

#elif defined(HAVE_GCC_DESTRUCTOR)

static void alc_init(void) __attribute__((constructor));
static void alc_deinit(void) __attribute__((destructor));

#else
#error "No global initialization available on this platform!"
#endif

static void ReleaseThreadCtx(ALCcontext *ctx);
static void alc_init(void)
{
    LogFile = stderr;

    const char *str{getenv("__ALSOFT_HALF_ANGLE_CONES")};
    if(str && (strcasecmp(str, "true") == 0 || strtol(str, nullptr, 0) == 1))
        ConeScale *= 0.5f;

    str = getenv("__ALSOFT_REVERSE_Z");
    if(str && (strcasecmp(str, "true") == 0 || strtol(str, nullptr, 0) == 1))
        ZScale *= -1.0f;

    str = getenv("__ALSOFT_REVERB_IGNORES_SOUND_SPEED");
    if(str && (strcasecmp(str, "true") == 0 || strtol(str, nullptr, 0) == 1))
        OverrideReverbSpeedOfSound = AL_TRUE;

    ThreadCtxProc = ReleaseThreadCtx;
}

static void alc_initconfig(void)
{
    const char *devs, *str;
    int capfilter;
    float valf;
    int i, n;

    str = getenv("ALSOFT_LOGLEVEL");
    if(str)
    {
        long lvl = strtol(str, nullptr, 0);
        if(lvl >= NoLog && lvl <= LogRef)
            LogLevel = static_cast<enum LogLevel>(lvl);
    }

    str = getenv("ALSOFT_LOGFILE");
    if(str && str[0])
    {
#ifdef _WIN32
        std::wstring wname{utf8_to_wstr(str)};
        FILE *logfile = _wfopen(wname.c_str(), L"wt");
#else
        FILE *logfile = fopen(str, "wt");
#endif
        if(logfile) LogFile = logfile;
        else ERR("Failed to open log file '%s'\n", str);
    }

    TRACE("Initializing library v%s-%s %s\n", ALSOFT_VERSION,
          ALSOFT_GIT_COMMIT_HASH, ALSOFT_GIT_BRANCH);
    {
        std::string names;
        if(BackendListSize > 0)
            names += BackendList[0].name;
        for(i = 1;i < BackendListSize;i++)
        {
            names += ", ";
            names += BackendList[i].name;
        }
        TRACE("Supported backends: %s\n", names.c_str());
    }
    ReadALConfig();

    str = getenv("__ALSOFT_SUSPEND_CONTEXT");
    if(str && *str)
    {
        if(strcasecmp(str, "ignore") == 0)
        {
            SuspendDefers = false;
            TRACE("Selected context suspend behavior, \"ignore\"\n");
        }
        else
            ERR("Unhandled context suspend behavior setting: \"%s\"\n", str);
    }

    capfilter = 0;
#if defined(HAVE_SSE4_1)
    capfilter |= CPU_CAP_SSE | CPU_CAP_SSE2 | CPU_CAP_SSE3 | CPU_CAP_SSE4_1;
#elif defined(HAVE_SSE3)
    capfilter |= CPU_CAP_SSE | CPU_CAP_SSE2 | CPU_CAP_SSE3;
#elif defined(HAVE_SSE2)
    capfilter |= CPU_CAP_SSE | CPU_CAP_SSE2;
#elif defined(HAVE_SSE)
    capfilter |= CPU_CAP_SSE;
#endif
#ifdef HAVE_NEON
    capfilter |= CPU_CAP_NEON;
#endif
    if(ConfigValueStr(nullptr, nullptr, "disable-cpu-exts", &str))
    {
        if(strcasecmp(str, "all") == 0)
            capfilter = 0;
        else
        {
            size_t len;
            const char *next = str;

            do {
                str = next;
                while(isspace(str[0]))
                    str++;
                next = strchr(str, ',');

                if(!str[0] || str[0] == ',')
                    continue;

                len = (next ? ((size_t)(next-str)) : strlen(str));
                while(len > 0 && isspace(str[len-1]))
                    len--;
                if(len == 3 && strncasecmp(str, "sse", len) == 0)
                    capfilter &= ~CPU_CAP_SSE;
                else if(len == 4 && strncasecmp(str, "sse2", len) == 0)
                    capfilter &= ~CPU_CAP_SSE2;
                else if(len == 4 && strncasecmp(str, "sse3", len) == 0)
                    capfilter &= ~CPU_CAP_SSE3;
                else if(len == 6 && strncasecmp(str, "sse4.1", len) == 0)
                    capfilter &= ~CPU_CAP_SSE4_1;
                else if(len == 4 && strncasecmp(str, "neon", len) == 0)
                    capfilter &= ~CPU_CAP_NEON;
                else
                    WARN("Invalid CPU extension \"%s\"\n", str);
            } while(next++);
        }
    }
    FillCPUCaps(capfilter);

#ifdef _WIN32
    RTPrioLevel = 1;
#else
    RTPrioLevel = 0;
#endif
    ConfigValueInt(nullptr, nullptr, "rt-prio", &RTPrioLevel);

    aluInit();
    aluInitMixer();

    str = getenv("ALSOFT_TRAP_ERROR");
    if(str && (strcasecmp(str, "true") == 0 || strtol(str, nullptr, 0) == 1))
    {
        TrapALError  = AL_TRUE;
        TrapALCError = true;
    }
    else
    {
        str = getenv("ALSOFT_TRAP_AL_ERROR");
        if(str && (strcasecmp(str, "true") == 0 || strtol(str, nullptr, 0) == 1))
            TrapALError = AL_TRUE;
        TrapALError = GetConfigValueBool(nullptr, nullptr, "trap-al-error", TrapALError);

        str = getenv("ALSOFT_TRAP_ALC_ERROR");
        if(str && (strcasecmp(str, "true") == 0 || strtol(str, nullptr, 0) == 1))
            TrapALCError = true;
        TrapALCError = !!GetConfigValueBool(nullptr, nullptr, "trap-alc-error", TrapALCError);
    }

    if(ConfigValueFloat(nullptr, "reverb", "boost", &valf))
        ReverbBoost *= std::pow(10.0f, valf / 20.0f);

    if(((devs=getenv("ALSOFT_DRIVERS")) && devs[0]) ||
       ConfigValueStr(nullptr, nullptr, "drivers", &devs))
    {
        int n;
        size_t len;
        const char *next = devs;
        int endlist, delitem;

        i = 0;
        do {
            devs = next;
            while(isspace(devs[0]))
                devs++;
            next = strchr(devs, ',');

            delitem = (devs[0] == '-');
            if(devs[0] == '-') devs++;

            if(!devs[0] || devs[0] == ',')
            {
                endlist = 0;
                continue;
            }
            endlist = 1;

            len = (next ? ((size_t)(next-devs)) : strlen(devs));
            while(len > 0 && isspace(devs[len-1]))
                len--;
#ifdef HAVE_WASAPI
            /* HACK: For backwards compatibility, convert backend references of
             * mmdevapi to wasapi. This should eventually be removed.
             */
            if(len == 8 && strncmp(devs, "mmdevapi", len) == 0)
            {
                devs = "wasapi";
                len = 6;
            }
#endif
            for(n = i;n < BackendListSize;n++)
            {
                if(len == strlen(BackendList[n].name) &&
                   strncmp(BackendList[n].name, devs, len) == 0)
                {
                    if(delitem)
                    {
                        for(;n+1 < BackendListSize;n++)
                            BackendList[n] = BackendList[n+1];
                        BackendListSize--;
                    }
                    else
                    {
                        struct BackendInfo Bkp = BackendList[n];
                        for(;n > i;n--)
                            BackendList[n] = BackendList[n-1];
                        BackendList[n] = Bkp;

                        i++;
                    }
                    break;
                }
            }
        } while(next++);

        if(endlist)
            BackendListSize = i;
    }

    for(n = i = 0;i < BackendListSize && (!PlaybackBackend.name || !CaptureBackend.name);i++)
    {
        BackendList[n] = BackendList[i];

        BackendFactory &factory = BackendList[n].getFactory();
        if(!factory.init())
        {
            WARN("Failed to initialize backend \"%s\"\n", BackendList[n].name);
            continue;
        }

        TRACE("Initialized backend \"%s\"\n", BackendList[n].name);
        if(!PlaybackBackend.name && factory.querySupport(ALCbackend_Playback))
        {
            PlaybackBackend = BackendList[n];
            TRACE("Added \"%s\" for playback\n", PlaybackBackend.name);
        }
        if(!CaptureBackend.name && factory.querySupport(ALCbackend_Capture))
        {
            CaptureBackend = BackendList[n];
            TRACE("Added \"%s\" for capture\n", CaptureBackend.name);
        }
        n++;
    }
    BackendListSize = n;

    LoopbackBackendFactory::getFactory().init();

    if(!PlaybackBackend.name)
        WARN("No playback backend available!\n");
    if(!CaptureBackend.name)
        WARN("No capture backend available!\n");

    if(ConfigValueStr(nullptr, nullptr, "excludefx", &str))
    {
        size_t len;
        const char *next = str;

        do {
            str = next;
            next = strchr(str, ',');

            if(!str[0] || next == str)
                continue;

            len = (next ? ((size_t)(next-str)) : strlen(str));
            for(n = 0;n < EFFECTLIST_SIZE;n++)
            {
                if(len == strlen(EffectList[n].name) &&
                   strncmp(EffectList[n].name, str, len) == 0)
                    DisabledEffects[EffectList[n].type] = AL_TRUE;
            }
        } while(next++);
    }

    InitEffect(&DefaultEffect);
    str = getenv("ALSOFT_DEFAULT_REVERB");
    if((str && str[0]) || ConfigValueStr(nullptr, nullptr, "default-reverb", &str))
        LoadReverbPreset(str, &DefaultEffect);
}
#define DO_INITCONFIG() std::call_once(alc_config_once, [](){alc_initconfig();})


/************************************************
 * Library deinitialization
 ************************************************/
static void alc_cleanup(void)
{
    alcAllDevicesList.clear();
    alcCaptureDeviceList.clear();

    alcDefaultAllDevicesSpecifier.clear();
    alcCaptureDefaultDeviceSpecifier.clear();

    if(ALCdevice *dev{DeviceList.exchange(nullptr)})
    {
        ALCuint num = 0;
        do {
            num++;
            dev = ATOMIC_LOAD(&dev->next, almemory_order_relaxed);
        } while(dev != nullptr);
        ERR("%u device%s not closed\n", num, (num>1)?"s":"");
    }
}

static void alc_deinit_safe(void)
{
    alc_cleanup();

    FreeHrtfs();
    FreeALConfig();

    ThreadCtxProc = nullptr;

    if(LogFile != stderr)
        fclose(LogFile);
    LogFile = nullptr;
}

static void alc_deinit(void)
{
    int i;

    alc_cleanup();

    memset(&PlaybackBackend, 0, sizeof(PlaybackBackend));
    memset(&CaptureBackend, 0, sizeof(CaptureBackend));

    for(i = 0;i < BackendListSize;i++)
        BackendList[i].getFactory().deinit();

    LoopbackBackendFactory::getFactory().deinit();

    alc_deinit_safe();
}


/************************************************
 * Device enumeration
 ************************************************/
static void ProbeDevices(std::string *list, struct BackendInfo *backendinfo, enum DevProbe type)
{
    DO_INITCONFIG();

    std::lock_guard<std::recursive_mutex> _{ListLock};
    list->clear();
    if(backendinfo->getFactory)
        backendinfo->getFactory().probe(type, list);
}
static void ProbeAllDevicesList(void)
{ ProbeDevices(&alcAllDevicesList, &PlaybackBackend, ALL_DEVICE_PROBE); }
static void ProbeCaptureDeviceList(void)
{ ProbeDevices(&alcCaptureDeviceList, &CaptureBackend, CAPTURE_DEVICE_PROBE); }


/************************************************
 * Device format information
 ************************************************/
const ALCchar *DevFmtTypeString(enum DevFmtType type)
{
    switch(type)
    {
    case DevFmtByte: return "Signed Byte";
    case DevFmtUByte: return "Unsigned Byte";
    case DevFmtShort: return "Signed Short";
    case DevFmtUShort: return "Unsigned Short";
    case DevFmtInt: return "Signed Int";
    case DevFmtUInt: return "Unsigned Int";
    case DevFmtFloat: return "Float";
    }
    return "(unknown type)";
}
const ALCchar *DevFmtChannelsString(enum DevFmtChannels chans)
{
    switch(chans)
    {
    case DevFmtMono: return "Mono";
    case DevFmtStereo: return "Stereo";
    case DevFmtQuad: return "Quadraphonic";
    case DevFmtX51: return "5.1 Surround";
    case DevFmtX51Rear: return "5.1 Surround (Rear)";
    case DevFmtX61: return "6.1 Surround";
    case DevFmtX71: return "7.1 Surround";
    case DevFmtAmbi3D: return "Ambisonic 3D";
    }
    return "(unknown channels)";
}

ALsizei BytesFromDevFmt(enum DevFmtType type)
{
    switch(type)
    {
    case DevFmtByte: return sizeof(ALbyte);
    case DevFmtUByte: return sizeof(ALubyte);
    case DevFmtShort: return sizeof(ALshort);
    case DevFmtUShort: return sizeof(ALushort);
    case DevFmtInt: return sizeof(ALint);
    case DevFmtUInt: return sizeof(ALuint);
    case DevFmtFloat: return sizeof(ALfloat);
    }
    return 0;
}
ALsizei ChannelsFromDevFmt(enum DevFmtChannels chans, ALsizei ambiorder)
{
    switch(chans)
    {
    case DevFmtMono: return 1;
    case DevFmtStereo: return 2;
    case DevFmtQuad: return 4;
    case DevFmtX51: return 6;
    case DevFmtX51Rear: return 6;
    case DevFmtX61: return 7;
    case DevFmtX71: return 8;
    case DevFmtAmbi3D: return (ambiorder >= 3) ? 16 :
                              (ambiorder == 2) ? 9 :
                              (ambiorder == 1) ? 4 : 1;
    }
    return 0;
}

static ALboolean DecomposeDevFormat(ALenum format, enum DevFmtChannels *chans,
                                    enum DevFmtType *type)
{
    static const struct {
        ALenum format;
        enum DevFmtChannels channels;
        enum DevFmtType type;
    } list[] = {
        { AL_FORMAT_MONO8,        DevFmtMono, DevFmtUByte },
        { AL_FORMAT_MONO16,       DevFmtMono, DevFmtShort },
        { AL_FORMAT_MONO_FLOAT32, DevFmtMono, DevFmtFloat },

        { AL_FORMAT_STEREO8,        DevFmtStereo, DevFmtUByte },
        { AL_FORMAT_STEREO16,       DevFmtStereo, DevFmtShort },
        { AL_FORMAT_STEREO_FLOAT32, DevFmtStereo, DevFmtFloat },

        { AL_FORMAT_QUAD8,  DevFmtQuad, DevFmtUByte },
        { AL_FORMAT_QUAD16, DevFmtQuad, DevFmtShort },
        { AL_FORMAT_QUAD32, DevFmtQuad, DevFmtFloat },

        { AL_FORMAT_51CHN8,  DevFmtX51, DevFmtUByte },
        { AL_FORMAT_51CHN16, DevFmtX51, DevFmtShort },
        { AL_FORMAT_51CHN32, DevFmtX51, DevFmtFloat },

        { AL_FORMAT_61CHN8,  DevFmtX61, DevFmtUByte },
        { AL_FORMAT_61CHN16, DevFmtX61, DevFmtShort },
        { AL_FORMAT_61CHN32, DevFmtX61, DevFmtFloat },

        { AL_FORMAT_71CHN8,  DevFmtX71, DevFmtUByte },
        { AL_FORMAT_71CHN16, DevFmtX71, DevFmtShort },
        { AL_FORMAT_71CHN32, DevFmtX71, DevFmtFloat },
    };
    ALuint i;

    for(i = 0;i < COUNTOF(list);i++)
    {
        if(list[i].format == format)
        {
            *chans = list[i].channels;
            *type  = list[i].type;
            return AL_TRUE;
        }
    }

    return AL_FALSE;
}

static ALCboolean IsValidALCType(ALCenum type)
{
    switch(type)
    {
        case ALC_BYTE_SOFT:
        case ALC_UNSIGNED_BYTE_SOFT:
        case ALC_SHORT_SOFT:
        case ALC_UNSIGNED_SHORT_SOFT:
        case ALC_INT_SOFT:
        case ALC_UNSIGNED_INT_SOFT:
        case ALC_FLOAT_SOFT:
            return ALC_TRUE;
    }
    return ALC_FALSE;
}

static ALCboolean IsValidALCChannels(ALCenum channels)
{
    switch(channels)
    {
        case ALC_MONO_SOFT:
        case ALC_STEREO_SOFT:
        case ALC_QUAD_SOFT:
        case ALC_5POINT1_SOFT:
        case ALC_6POINT1_SOFT:
        case ALC_7POINT1_SOFT:
        case ALC_BFORMAT3D_SOFT:
            return ALC_TRUE;
    }
    return ALC_FALSE;
}

static ALCboolean IsValidAmbiLayout(ALCenum layout)
{
    switch(layout)
    {
        case ALC_ACN_SOFT:
        case ALC_FUMA_SOFT:
            return ALC_TRUE;
    }
    return ALC_FALSE;
}

static ALCboolean IsValidAmbiScaling(ALCenum scaling)
{
    switch(scaling)
    {
        case ALC_N3D_SOFT:
        case ALC_SN3D_SOFT:
        case ALC_FUMA_SOFT:
            return ALC_TRUE;
    }
    return ALC_FALSE;
}

/************************************************
 * Miscellaneous ALC helpers
 ************************************************/

/* SetDefaultWFXChannelOrder
 *
 * Sets the default channel order used by WaveFormatEx.
 */
void SetDefaultWFXChannelOrder(ALCdevice *device)
{
    ALsizei i;

    for(i = 0;i < MAX_OUTPUT_CHANNELS;i++)
        device->RealOut.ChannelName[i] = InvalidChannel;

    switch(device->FmtChans)
    {
    case DevFmtMono:
        device->RealOut.ChannelName[0] = FrontCenter;
        break;
    case DevFmtStereo:
        device->RealOut.ChannelName[0] = FrontLeft;
        device->RealOut.ChannelName[1] = FrontRight;
        break;
    case DevFmtQuad:
        device->RealOut.ChannelName[0] = FrontLeft;
        device->RealOut.ChannelName[1] = FrontRight;
        device->RealOut.ChannelName[2] = BackLeft;
        device->RealOut.ChannelName[3] = BackRight;
        break;
    case DevFmtX51:
        device->RealOut.ChannelName[0] = FrontLeft;
        device->RealOut.ChannelName[1] = FrontRight;
        device->RealOut.ChannelName[2] = FrontCenter;
        device->RealOut.ChannelName[3] = LFE;
        device->RealOut.ChannelName[4] = SideLeft;
        device->RealOut.ChannelName[5] = SideRight;
        break;
    case DevFmtX51Rear:
        device->RealOut.ChannelName[0] = FrontLeft;
        device->RealOut.ChannelName[1] = FrontRight;
        device->RealOut.ChannelName[2] = FrontCenter;
        device->RealOut.ChannelName[3] = LFE;
        device->RealOut.ChannelName[4] = BackLeft;
        device->RealOut.ChannelName[5] = BackRight;
        break;
    case DevFmtX61:
        device->RealOut.ChannelName[0] = FrontLeft;
        device->RealOut.ChannelName[1] = FrontRight;
        device->RealOut.ChannelName[2] = FrontCenter;
        device->RealOut.ChannelName[3] = LFE;
        device->RealOut.ChannelName[4] = BackCenter;
        device->RealOut.ChannelName[5] = SideLeft;
        device->RealOut.ChannelName[6] = SideRight;
        break;
    case DevFmtX71:
        device->RealOut.ChannelName[0] = FrontLeft;
        device->RealOut.ChannelName[1] = FrontRight;
        device->RealOut.ChannelName[2] = FrontCenter;
        device->RealOut.ChannelName[3] = LFE;
        device->RealOut.ChannelName[4] = BackLeft;
        device->RealOut.ChannelName[5] = BackRight;
        device->RealOut.ChannelName[6] = SideLeft;
        device->RealOut.ChannelName[7] = SideRight;
        break;
    case DevFmtAmbi3D:
        device->RealOut.ChannelName[0] = Aux0;
        if(device->mAmbiOrder > 0)
        {
            device->RealOut.ChannelName[1] = Aux1;
            device->RealOut.ChannelName[2] = Aux2;
            device->RealOut.ChannelName[3] = Aux3;
        }
        if(device->mAmbiOrder > 1)
        {
            device->RealOut.ChannelName[4] = Aux4;
            device->RealOut.ChannelName[5] = Aux5;
            device->RealOut.ChannelName[6] = Aux6;
            device->RealOut.ChannelName[7] = Aux7;
            device->RealOut.ChannelName[8] = Aux8;
        }
        if(device->mAmbiOrder > 2)
        {
            device->RealOut.ChannelName[9]  = Aux9;
            device->RealOut.ChannelName[10] = Aux10;
            device->RealOut.ChannelName[11] = Aux11;
            device->RealOut.ChannelName[12] = Aux12;
            device->RealOut.ChannelName[13] = Aux13;
            device->RealOut.ChannelName[14] = Aux14;
            device->RealOut.ChannelName[15] = Aux15;
        }
        break;
    }
}

/* SetDefaultChannelOrder
 *
 * Sets the default channel order used by most non-WaveFormatEx-based APIs.
 */
void SetDefaultChannelOrder(ALCdevice *device)
{
    ALsizei i;

    for(i = 0;i < MAX_OUTPUT_CHANNELS;i++)
        device->RealOut.ChannelName[i] = InvalidChannel;

    switch(device->FmtChans)
    {
    case DevFmtX51Rear:
        device->RealOut.ChannelName[0] = FrontLeft;
        device->RealOut.ChannelName[1] = FrontRight;
        device->RealOut.ChannelName[2] = BackLeft;
        device->RealOut.ChannelName[3] = BackRight;
        device->RealOut.ChannelName[4] = FrontCenter;
        device->RealOut.ChannelName[5] = LFE;
        return;
    case DevFmtX71:
        device->RealOut.ChannelName[0] = FrontLeft;
        device->RealOut.ChannelName[1] = FrontRight;
        device->RealOut.ChannelName[2] = BackLeft;
        device->RealOut.ChannelName[3] = BackRight;
        device->RealOut.ChannelName[4] = FrontCenter;
        device->RealOut.ChannelName[5] = LFE;
        device->RealOut.ChannelName[6] = SideLeft;
        device->RealOut.ChannelName[7] = SideRight;
        return;

    /* Same as WFX order */
    case DevFmtMono:
    case DevFmtStereo:
    case DevFmtQuad:
    case DevFmtX51:
    case DevFmtX61:
    case DevFmtAmbi3D:
        SetDefaultWFXChannelOrder(device);
        break;
    }
}


/* ALCcontext_DeferUpdates
 *
 * Defers/suspends updates for the given context's listener and sources. This
 * does *NOT* stop mixing, but rather prevents certain property changes from
 * taking effect.
 */
void ALCcontext_DeferUpdates(ALCcontext *context)
{
    ATOMIC_STORE_SEQ(&context->DeferUpdates, AL_TRUE);
}

/* ALCcontext_ProcessUpdates
 *
 * Resumes update processing after being deferred.
 */
void ALCcontext_ProcessUpdates(ALCcontext *context)
{
    almtx_lock(&context->PropLock);
    if(context->DeferUpdates.exchange(AL_FALSE))
    {
        /* Tell the mixer to stop applying updates, then wait for any active
         * updating to finish, before providing updates.
         */
        ATOMIC_STORE_SEQ(&context->HoldUpdates, AL_TRUE);
        while((ATOMIC_LOAD(&context->UpdateCount, almemory_order_acquire)&1) != 0)
            althrd_yield();

        if(!context->PropsClean.exchange(AL_TRUE, std::memory_order_acq_rel))
            UpdateContextProps(context);
        if(!context->Listener.PropsClean.exchange(AL_TRUE, std::memory_order_acq_rel))
            UpdateListenerProps(context);
        UpdateAllEffectSlotProps(context);
        UpdateAllSourceProps(context);

        /* Now with all updates declared, let the mixer continue applying them
         * so they all happen at once.
         */
        ATOMIC_STORE_SEQ(&context->HoldUpdates, AL_FALSE);
    }
    almtx_unlock(&context->PropLock);
}


/* alcSetError
 *
 * Stores the latest ALC device error
 */
static void alcSetError(ALCdevice *device, ALCenum errorCode)
{
    WARN("Error generated on device %p, code 0x%04x\n", device, errorCode);
    if(TrapALCError)
    {
#ifdef _WIN32
        /* DebugBreak() will cause an exception if there is no debugger */
        if(IsDebuggerPresent())
            DebugBreak();
#elif defined(SIGTRAP)
        raise(SIGTRAP);
#endif
    }

    if(device)
        ATOMIC_STORE_SEQ(&device->LastError, errorCode);
    else
        LastNullDeviceError.store(errorCode);
}


static struct Compressor *CreateDeviceLimiter(const ALCdevice *device, const ALfloat threshold)
{
    return CompressorInit(device->RealOut.NumChannels, device->Frequency,
        AL_TRUE, AL_TRUE, AL_TRUE, AL_TRUE, AL_TRUE, 0.001f, 0.002f,
        0.0f, 0.0f, threshold, INFINITY, 0.0f, 0.020f, 0.200f);
}

/* UpdateClockBase
 *
 * Updates the device's base clock time with however many samples have been
 * done. This is used so frequency changes on the device don't cause the time
 * to jump forward or back. Must not be called while the device is running/
 * mixing.
 */
static inline void UpdateClockBase(ALCdevice *device)
{
    IncrementRef(&device->MixCount);
    device->ClockBase += device->SamplesDone * DEVICE_CLOCK_RES / device->Frequency;
    device->SamplesDone = 0;
    IncrementRef(&device->MixCount);
}

/* UpdateDeviceParams
 *
 * Updates device parameters according to the attribute list (caller is
 * responsible for holding the list lock).
 */
static ALCenum UpdateDeviceParams(ALCdevice *device, const ALCint *attrList)
{
    enum HrtfRequestMode hrtf_userreq = Hrtf_Default;
    enum HrtfRequestMode hrtf_appreq = Hrtf_Default;
    ALCenum gainLimiter = device->LimiterState;
    const ALsizei old_sends = device->NumAuxSends;
    ALsizei new_sends = device->NumAuxSends;
    enum DevFmtChannels oldChans;
    enum DevFmtType oldType;
    ALboolean update_failed;
    ALCsizei hrtf_id = -1;
    ALCcontext *context;
    ALCuint oldFreq;
    size_t size;
    ALCsizei i;
    int val;

    // Check for attributes
    if(device->Type == Loopback)
    {
        ALCsizei numMono, numStereo, numSends;
        ALCenum alayout = AL_NONE;
        ALCenum ascale = AL_NONE;
        ALCenum schans = AL_NONE;
        ALCenum stype = AL_NONE;
        ALCsizei attrIdx = 0;
        ALCsizei aorder = 0;
        ALCuint freq = 0;

        if(!attrList)
        {
            WARN("Missing attributes for loopback device\n");
            return ALC_INVALID_VALUE;
        }

        numMono = device->NumMonoSources;
        numStereo = device->NumStereoSources;
        numSends = old_sends;

#define TRACE_ATTR(a, v) TRACE("Loopback %s = %d\n", #a, v)
        while(attrList[attrIdx])
        {
            switch(attrList[attrIdx])
            {
                case ALC_FORMAT_CHANNELS_SOFT:
                    schans = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_FORMAT_CHANNELS_SOFT, schans);
                    if(!IsValidALCChannels(schans))
                        return ALC_INVALID_VALUE;
                    break;

                case ALC_FORMAT_TYPE_SOFT:
                    stype = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_FORMAT_TYPE_SOFT, stype);
                    if(!IsValidALCType(stype))
                        return ALC_INVALID_VALUE;
                    break;

                case ALC_FREQUENCY:
                    freq = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_FREQUENCY, freq);
                    if(freq < MIN_OUTPUT_RATE)
                        return ALC_INVALID_VALUE;
                    break;

                case ALC_AMBISONIC_LAYOUT_SOFT:
                    alayout = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_AMBISONIC_LAYOUT_SOFT, alayout);
                    if(!IsValidAmbiLayout(alayout))
                        return ALC_INVALID_VALUE;
                    break;

                case ALC_AMBISONIC_SCALING_SOFT:
                    ascale = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_AMBISONIC_SCALING_SOFT, ascale);
                    if(!IsValidAmbiScaling(ascale))
                        return ALC_INVALID_VALUE;
                    break;

                case ALC_AMBISONIC_ORDER_SOFT:
                    aorder = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_AMBISONIC_ORDER_SOFT, aorder);
                    if(aorder < 1 || aorder > MAX_AMBI_ORDER)
                        return ALC_INVALID_VALUE;
                    break;

                case ALC_MONO_SOURCES:
                    numMono = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_MONO_SOURCES, numMono);
                    numMono = maxi(numMono, 0);
                    break;

                case ALC_STEREO_SOURCES:
                    numStereo = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_STEREO_SOURCES, numStereo);
                    numStereo = maxi(numStereo, 0);
                    break;

                case ALC_MAX_AUXILIARY_SENDS:
                    numSends = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_MAX_AUXILIARY_SENDS, numSends);
                    numSends = clampi(numSends, 0, MAX_SENDS);
                    break;

                case ALC_HRTF_SOFT:
                    TRACE_ATTR(ALC_HRTF_SOFT, attrList[attrIdx + 1]);
                    if(attrList[attrIdx + 1] == ALC_FALSE)
                        hrtf_appreq = Hrtf_Disable;
                    else if(attrList[attrIdx + 1] == ALC_TRUE)
                        hrtf_appreq = Hrtf_Enable;
                    else
                        hrtf_appreq = Hrtf_Default;
                    break;

                case ALC_HRTF_ID_SOFT:
                    hrtf_id = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_HRTF_ID_SOFT, hrtf_id);
                    break;

                case ALC_OUTPUT_LIMITER_SOFT:
                    gainLimiter = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_OUTPUT_LIMITER_SOFT, gainLimiter);
                    break;

                default:
                    TRACE("Loopback 0x%04X = %d (0x%x)\n", attrList[attrIdx],
                          attrList[attrIdx + 1], attrList[attrIdx + 1]);
                    break;
            }

            attrIdx += 2;
        }
#undef TRACE_ATTR

        if(!schans || !stype || !freq)
        {
            WARN("Missing format for loopback device\n");
            return ALC_INVALID_VALUE;
        }
        if(schans == ALC_BFORMAT3D_SOFT && (!alayout || !ascale || !aorder))
        {
            WARN("Missing ambisonic info for loopback device\n");
            return ALC_INVALID_VALUE;
        }

        if((device->Flags&DEVICE_RUNNING))
            V0(device->Backend,stop)();
        device->Flags &= ~DEVICE_RUNNING;

        UpdateClockBase(device);

        device->Frequency = freq;
        device->FmtChans = static_cast<enum DevFmtChannels>(schans);
        device->FmtType = static_cast<enum DevFmtType>(stype);
        if(schans == ALC_BFORMAT3D_SOFT)
        {
            device->mAmbiOrder = aorder;
            device->mAmbiLayout = static_cast<enum AmbiLayout>(alayout);
            device->mAmbiScale = static_cast<enum AmbiNorm>(ascale);
        }

        if(numMono > INT_MAX-numStereo)
            numMono = INT_MAX-numStereo;
        numMono += numStereo;
        if(ConfigValueInt(nullptr, nullptr, "sources", &numMono))
        {
            if(numMono <= 0)
                numMono = 256;
        }
        else
            numMono = maxi(numMono, 256);
        numStereo = mini(numStereo, numMono);
        numMono -= numStereo;
        device->SourcesMax = numMono + numStereo;

        device->NumMonoSources = numMono;
        device->NumStereoSources = numStereo;

        if(ConfigValueInt(nullptr, nullptr, "sends", &new_sends))
            new_sends = mini(numSends, clampi(new_sends, 0, MAX_SENDS));
        else
            new_sends = numSends;
    }
    else if(attrList && attrList[0])
    {
        ALCsizei numMono, numStereo, numSends;
        ALCsizei attrIdx = 0;
        ALCuint freq;

        /* If a context is already running on the device, stop playback so the
         * device attributes can be updated. */
        if((device->Flags&DEVICE_RUNNING))
            V0(device->Backend,stop)();
        device->Flags &= ~DEVICE_RUNNING;

        UpdateClockBase(device);

        freq = device->Frequency;
        numMono = device->NumMonoSources;
        numStereo = device->NumStereoSources;
        numSends = old_sends;

#define TRACE_ATTR(a, v) TRACE("%s = %d\n", #a, v)
        while(attrList[attrIdx])
        {
            switch(attrList[attrIdx])
            {
                case ALC_FREQUENCY:
                    freq = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_FREQUENCY, freq);
                    device->Flags |= DEVICE_FREQUENCY_REQUEST;
                    break;

                case ALC_MONO_SOURCES:
                    numMono = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_MONO_SOURCES, numMono);
                    numMono = maxi(numMono, 0);
                    break;

                case ALC_STEREO_SOURCES:
                    numStereo = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_STEREO_SOURCES, numStereo);
                    numStereo = maxi(numStereo, 0);
                    break;

                case ALC_MAX_AUXILIARY_SENDS:
                    numSends = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_MAX_AUXILIARY_SENDS, numSends);
                    numSends = clampi(numSends, 0, MAX_SENDS);
                    break;

                case ALC_HRTF_SOFT:
                    TRACE_ATTR(ALC_HRTF_SOFT, attrList[attrIdx + 1]);
                    if(attrList[attrIdx + 1] == ALC_FALSE)
                        hrtf_appreq = Hrtf_Disable;
                    else if(attrList[attrIdx + 1] == ALC_TRUE)
                        hrtf_appreq = Hrtf_Enable;
                    else
                        hrtf_appreq = Hrtf_Default;
                    break;

                case ALC_HRTF_ID_SOFT:
                    hrtf_id = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_HRTF_ID_SOFT, hrtf_id);
                    break;

                case ALC_OUTPUT_LIMITER_SOFT:
                    gainLimiter = attrList[attrIdx + 1];
                    TRACE_ATTR(ALC_OUTPUT_LIMITER_SOFT, gainLimiter);
                    break;

                default:
                    TRACE("0x%04X = %d (0x%x)\n", attrList[attrIdx],
                          attrList[attrIdx + 1], attrList[attrIdx + 1]);
                    break;
            }

            attrIdx += 2;
        }
#undef TRACE_ATTR

        ConfigValueUInt(device->DeviceName.c_str(), nullptr, "frequency", &freq);
        freq = maxu(freq, MIN_OUTPUT_RATE);

        device->UpdateSize = (ALuint64)device->UpdateSize * freq /
                             device->Frequency;
        /* SSE and Neon do best with the update size being a multiple of 4 */
        if((CPUCapFlags&(CPU_CAP_SSE|CPU_CAP_NEON)) != 0)
            device->UpdateSize = (device->UpdateSize+3)&~3;

        device->Frequency = freq;

        if(numMono > INT_MAX-numStereo)
            numMono = INT_MAX-numStereo;
        numMono += numStereo;
        if(ConfigValueInt(device->DeviceName.c_str(), nullptr, "sources", &numMono))
        {
            if(numMono <= 0)
                numMono = 256;
        }
        else
            numMono = maxi(numMono, 256);
        numStereo = mini(numStereo, numMono);
        numMono -= numStereo;
        device->SourcesMax = numMono + numStereo;

        device->NumMonoSources = numMono;
        device->NumStereoSources = numStereo;

        if(ConfigValueInt(device->DeviceName.c_str(), nullptr, "sends", &new_sends))
            new_sends = mini(numSends, clampi(new_sends, 0, MAX_SENDS));
        else
            new_sends = numSends;
    }

    if((device->Flags&DEVICE_RUNNING))
        return ALC_NO_ERROR;

    al_free(device->Uhj_Encoder);
    device->Uhj_Encoder = nullptr;

    al_free(device->Bs2b);
    device->Bs2b = nullptr;

    al_free(device->ChannelDelay[0].Buffer);
    for(i = 0;i < MAX_OUTPUT_CHANNELS;i++)
    {
        device->ChannelDelay[i].Length = 0;
        device->ChannelDelay[i].Buffer = nullptr;
    }

    al_free(device->Dry.Buffer);
    device->Dry.Buffer = nullptr;
    device->Dry.NumChannels = 0;
    device->FOAOut.Buffer = nullptr;
    device->FOAOut.NumChannels = 0;
    device->RealOut.Buffer = nullptr;
    device->RealOut.NumChannels = 0;

    UpdateClockBase(device);
    device->FixedLatency = 0;

    device->DitherSeed = DITHER_RNG_SEED;

    /*************************************************************************
     * Update device format request if HRTF is requested
     */
    device->HrtfStatus = ALC_HRTF_DISABLED_SOFT;
    if(device->Type != Loopback)
    {
        const char *hrtf;
        if(ConfigValueStr(device->DeviceName.c_str(), nullptr, "hrtf", &hrtf))
        {
            if(strcasecmp(hrtf, "true") == 0)
                hrtf_userreq = Hrtf_Enable;
            else if(strcasecmp(hrtf, "false") == 0)
                hrtf_userreq = Hrtf_Disable;
            else if(strcasecmp(hrtf, "auto") != 0)
                ERR("Unexpected hrtf value: %s\n", hrtf);
        }

        if(hrtf_userreq == Hrtf_Enable || (hrtf_userreq != Hrtf_Disable && hrtf_appreq == Hrtf_Enable))
        {
            struct Hrtf *hrtf = nullptr;
            if(device->HrtfList.empty())
                device->HrtfList = EnumerateHrtf(device->DeviceName.c_str());
            if(!device->HrtfList.empty())
            {
                if(hrtf_id >= 0 && (size_t)hrtf_id < device->HrtfList.size())
                    hrtf = GetLoadedHrtf(device->HrtfList[hrtf_id].hrtf);
                else
                    hrtf = GetLoadedHrtf(device->HrtfList.front().hrtf);
            }

            if(hrtf)
            {
                device->FmtChans = DevFmtStereo;
                device->Frequency = hrtf->sampleRate;
                device->Flags |= DEVICE_CHANNELS_REQUEST | DEVICE_FREQUENCY_REQUEST;
                if(device->HrtfHandle)
                    Hrtf_DecRef(device->HrtfHandle);
                device->HrtfHandle = hrtf;
            }
            else
            {
                hrtf_userreq = Hrtf_Default;
                hrtf_appreq = Hrtf_Disable;
                device->HrtfStatus = ALC_HRTF_UNSUPPORTED_FORMAT_SOFT;
            }
        }
    }

    oldFreq  = device->Frequency;
    oldChans = device->FmtChans;
    oldType  = device->FmtType;

    TRACE("Pre-reset: %s%s, %s%s, %s%uhz, %u update size x%d\n",
        (device->Flags&DEVICE_CHANNELS_REQUEST)?"*":"", DevFmtChannelsString(device->FmtChans),
        (device->Flags&DEVICE_SAMPLE_TYPE_REQUEST)?"*":"", DevFmtTypeString(device->FmtType),
        (device->Flags&DEVICE_FREQUENCY_REQUEST)?"*":"", device->Frequency,
        device->UpdateSize, device->NumUpdates
    );

    if(V0(device->Backend,reset)() == ALC_FALSE)
        return ALC_INVALID_DEVICE;

    if(device->FmtChans != oldChans && (device->Flags&DEVICE_CHANNELS_REQUEST))
    {
        ERR("Failed to set %s, got %s instead\n", DevFmtChannelsString(oldChans),
            DevFmtChannelsString(device->FmtChans));
        device->Flags &= ~DEVICE_CHANNELS_REQUEST;
    }
    if(device->FmtType != oldType && (device->Flags&DEVICE_SAMPLE_TYPE_REQUEST))
    {
        ERR("Failed to set %s, got %s instead\n", DevFmtTypeString(oldType),
            DevFmtTypeString(device->FmtType));
        device->Flags &= ~DEVICE_SAMPLE_TYPE_REQUEST;
    }
    if(device->Frequency != oldFreq && (device->Flags&DEVICE_FREQUENCY_REQUEST))
    {
        ERR("Failed to set %uhz, got %uhz instead\n", oldFreq, device->Frequency);
        device->Flags &= ~DEVICE_FREQUENCY_REQUEST;
    }

    if((device->UpdateSize&3) != 0)
    {
        if((CPUCapFlags&CPU_CAP_SSE))
            WARN("SSE performs best with multiple of 4 update sizes (%u)\n", device->UpdateSize);
        if((CPUCapFlags&CPU_CAP_NEON))
            WARN("NEON performs best with multiple of 4 update sizes (%u)\n", device->UpdateSize);
    }

    TRACE("Post-reset: %s, %s, %uhz, %u update size x%d\n",
        DevFmtChannelsString(device->FmtChans), DevFmtTypeString(device->FmtType),
        device->Frequency, device->UpdateSize, device->NumUpdates
    );

    aluInitRenderer(device, hrtf_id, hrtf_appreq, hrtf_userreq);
    TRACE("Channel config, Dry: %d, FOA: %d, Real: %d\n", device->Dry.NumChannels,
          device->FOAOut.NumChannels, device->RealOut.NumChannels);

    /* Allocate extra channels for any post-filter output. */
    size = (device->Dry.NumChannels + device->FOAOut.NumChannels +
            device->RealOut.NumChannels)*sizeof(device->Dry.Buffer[0]);

    TRACE("Allocating " SZFMT " channels, " SZFMT " bytes\n", size/sizeof(device->Dry.Buffer[0]), size);
    device->Dry.Buffer = static_cast<float(*)[BUFFERSIZE]>(al_calloc(16, size));
    if(!device->Dry.Buffer)
    {
        ERR("Failed to allocate " SZFMT " bytes for mix buffer\n", size);
        return ALC_INVALID_DEVICE;
    }

    if(device->RealOut.NumChannels != 0)
        device->RealOut.Buffer = device->Dry.Buffer + device->Dry.NumChannels +
                                 device->FOAOut.NumChannels;
    else
    {
        device->RealOut.Buffer = device->Dry.Buffer;
        device->RealOut.NumChannels = device->Dry.NumChannels;
    }

    if(device->FOAOut.NumChannels != 0)
        device->FOAOut.Buffer = device->Dry.Buffer + device->Dry.NumChannels;
    else
    {
        device->FOAOut.Buffer = device->Dry.Buffer;
        device->FOAOut.NumChannels = device->Dry.NumChannels;
    }

    device->NumAuxSends = new_sends;
    TRACE("Max sources: %d (%d + %d), effect slots: %d, sends: %d\n",
          device->SourcesMax, device->NumMonoSources, device->NumStereoSources,
          device->AuxiliaryEffectSlotMax, device->NumAuxSends);

    device->DitherDepth = 0.0f;
    if(GetConfigValueBool(device->DeviceName.c_str(), nullptr, "dither", 1))
    {
        ALint depth = 0;
        ConfigValueInt(device->DeviceName.c_str(), nullptr, "dither-depth", &depth);
        if(depth <= 0)
        {
            switch(device->FmtType)
            {
                case DevFmtByte:
                case DevFmtUByte:
                    depth = 8;
                    break;
                case DevFmtShort:
                case DevFmtUShort:
                    depth = 16;
                    break;
                case DevFmtInt:
                case DevFmtUInt:
                case DevFmtFloat:
                    break;
            }
        }

        if(depth > 0)
        {
            depth = clampi(depth, 2, 24);
            device->DitherDepth = std::pow(2.0f, (ALfloat)(depth-1));
        }
    }
    if(!(device->DitherDepth > 0.0f))
        TRACE("Dithering disabled\n");
    else
        TRACE("Dithering enabled (%d-bit, %g)\n", float2int(std::log2(device->DitherDepth)+0.5f)+1,
              device->DitherDepth);

    device->LimiterState = gainLimiter;
    if(ConfigValueBool(device->DeviceName.c_str(), nullptr, "output-limiter", &val))
        gainLimiter = val ? ALC_TRUE : ALC_FALSE;

    /* Valid values for gainLimiter are ALC_DONT_CARE_SOFT, ALC_TRUE, and
     * ALC_FALSE. For ALC_DONT_CARE_SOFT, use the limiter for integer-based
     * output (where samples must be clamped), and don't for floating-point
     * (which can take unclamped samples).
     */
    if(gainLimiter == ALC_DONT_CARE_SOFT)
    {
        switch(device->FmtType)
        {
            case DevFmtByte:
            case DevFmtUByte:
            case DevFmtShort:
            case DevFmtUShort:
            case DevFmtInt:
            case DevFmtUInt:
                gainLimiter = ALC_TRUE;
                break;
            case DevFmtFloat:
                gainLimiter = ALC_FALSE;
                break;
        }
    }
    if(gainLimiter != ALC_FALSE)
    {
        ALfloat thrshld = 1.0f;
        switch(device->FmtType)
        {
            case DevFmtByte:
            case DevFmtUByte:
                thrshld = 127.0f / 128.0f;
                break;
            case DevFmtShort:
            case DevFmtUShort:
                thrshld = 32767.0f / 32768.0f;
                break;
            case DevFmtInt:
            case DevFmtUInt:
            case DevFmtFloat:
                break;
        }
        if(device->DitherDepth > 0.0f)
            thrshld -= 1.0f / device->DitherDepth;

        al_free(device->Limiter);
        device->Limiter = CreateDeviceLimiter(device, std::log10(thrshld) * 20.0f);
        device->FixedLatency += (ALuint)(GetCompressorLookAhead(device->Limiter) *
                                         DEVICE_CLOCK_RES / device->Frequency);
    }
    else
    {
        al_free(device->Limiter);
        device->Limiter = nullptr;
    }
    TRACE("Output limiter %s\n", device->Limiter ? "enabled" : "disabled");

    aluSelectPostProcess(device);

    TRACE("Fixed device latency: %uns\n", device->FixedLatency);

    /* Need to delay returning failure until replacement Send arrays have been
     * allocated with the appropriate size.
     */
    update_failed = AL_FALSE;
    START_MIXER_MODE();
    context = ATOMIC_LOAD_SEQ(&device->ContextList);
    while(context)
    {
        struct ALvoiceProps *vprops;
        ALsizei pos;

        if(context->DefaultSlot)
        {
            ALeffectslot *slot = context->DefaultSlot;
            ALeffectState *state = slot->Effect.State;

            state->OutBuffer = device->Dry.Buffer;
            state->OutChannels = device->Dry.NumChannels;
            if(V(state,deviceUpdate)(device) == AL_FALSE)
                update_failed = AL_TRUE;
            else
                UpdateEffectSlotProps(slot, context);
        }

        almtx_lock(&context->PropLock);
        almtx_lock(&context->EffectSlotLock);
        for(auto &slot : context->EffectSlotList)
        {
            ALeffectState *state = slot->Effect.State;

            state->OutBuffer = device->Dry.Buffer;
            state->OutChannels = device->Dry.NumChannels;
            if(V(state,deviceUpdate)(device) == AL_FALSE)
                update_failed = AL_TRUE;
            else
                UpdateEffectSlotProps(slot, context);
        }
        almtx_unlock(&context->EffectSlotLock);

        almtx_lock(&context->SourceLock);
        for(auto &sublist : context->SourceList)
        {
            uint64_t usemask = ~sublist.FreeMask;
            while(usemask)
            {
                ALsizei idx = CTZ64(usemask);
                ALsource *source = sublist.Sources + idx;

                usemask &= ~(U64(1) << idx);

                if(old_sends != device->NumAuxSends)
                {
                    ALvoid *sends = al_calloc(16, device->NumAuxSends*sizeof(source->Send[0]));
                    ALsizei s;

                    memcpy(sends, source->Send,
                        mini(device->NumAuxSends, old_sends)*sizeof(source->Send[0])
                    );
                    for(s = device->NumAuxSends;s < old_sends;s++)
                    {
                        if(source->Send[s].Slot)
                            DecrementRef(&source->Send[s].Slot->ref);
                        source->Send[s].Slot = nullptr;
                    }
                    al_free(source->Send);
                    source->Send = static_cast<decltype(source->Send)>(sends);
                    for(s = old_sends;s < device->NumAuxSends;s++)
                    {
                        source->Send[s].Slot = nullptr;
                        source->Send[s].Gain = 1.0f;
                        source->Send[s].GainHF = 1.0f;
                        source->Send[s].HFReference = LOWPASSFREQREF;
                        source->Send[s].GainLF = 1.0f;
                        source->Send[s].LFReference = HIGHPASSFREQREF;
                    }
                }

                ATOMIC_STORE(&source->PropsClean, AL_FALSE, almemory_order_release);
            }
        }

        /* Clear any pre-existing voice property structs, in case the number of
         * auxiliary sends is changing. Active sources will have updates
         * respecified in UpdateAllSourceProps.
         */
        vprops = context->FreeVoiceProps.exchange(nullptr, std::memory_order_acq_rel);
        while(vprops)
        {
            struct ALvoiceProps *next = vprops->next.load(std::memory_order_relaxed);
            al_free(vprops);
            vprops = next;
        }

        AllocateVoices(context, context->MaxVoices, old_sends);
        for(pos = 0;pos < context->VoiceCount;pos++)
        {
            ALvoice *voice = context->Voices[pos];

            al_free(voice->Update.exchange(nullptr, std::memory_order_acq_rel));

            if(voice->Source.load(std::memory_order_acquire) == nullptr)
                continue;

            if(device->AvgSpeakerDist > 0.0f)
            {
                /* Reinitialize the NFC filters for new parameters. */
                ALfloat w1 = SPEEDOFSOUNDMETRESPERSEC /
                             (device->AvgSpeakerDist * device->Frequency);
                for(i = 0;i < voice->NumChannels;i++)
                    NfcFilterCreate(&voice->Direct.Params[i].NFCtrlFilter, 0.0f, w1);
            }
        }
        almtx_unlock(&context->SourceLock);

        ATOMIC_STORE(&context->PropsClean, AL_TRUE, almemory_order_release);
        UpdateContextProps(context);
        ATOMIC_STORE(&context->Listener.PropsClean, AL_TRUE, almemory_order_release);
        UpdateListenerProps(context);
        UpdateAllSourceProps(context);
        almtx_unlock(&context->PropLock);

        context = ATOMIC_LOAD(&context->next, almemory_order_relaxed);
    }
    END_MIXER_MODE();
    if(update_failed)
        return ALC_INVALID_DEVICE;

    if(!(device->Flags&DEVICE_PAUSED))
    {
        if(V0(device->Backend,start)() == ALC_FALSE)
            return ALC_INVALID_DEVICE;
        device->Flags |= DEVICE_RUNNING;
    }

    return ALC_NO_ERROR;
}


ALCdevice_struct::ALCdevice_struct(DeviceType type)
  : Type{type}
{
    almtx_init(&BufferLock, almtx_plain);
    almtx_init(&EffectLock, almtx_plain);
    almtx_init(&FilterLock, almtx_plain);

    almtx_init(&BackendLock, almtx_plain);
}

/* ALCdevice_struct::~ALCdevice_struct
 *
 * Frees the device structure, and destroys any objects the app failed to
 * delete. Called once there's no more references on the device.
 */
ALCdevice_struct::~ALCdevice_struct()
{
    TRACE("%p\n", this);

    if(Backend)
        DELETE_OBJ(Backend);
    Backend = nullptr;

    almtx_destroy(&BackendLock);

    ReleaseALBuffers(this);
    std::for_each(BufferList.begin(), BufferList.end(),
        [](BufferSubList &entry) noexcept -> void
        { al_free(entry.Buffers); }
    );
    BufferList.clear();
    almtx_destroy(&BufferLock);

    ReleaseALEffects(this);
    std::for_each(EffectList.begin(), EffectList.end(),
        [](EffectSubList &entry) noexcept -> void
        { al_free(entry.Effects); }
    );
    EffectList.clear();
    almtx_destroy(&EffectLock);

    ReleaseALFilters(this);
    std::for_each(FilterList.begin(), FilterList.end(),
        [](FilterSubList &entry) noexcept -> void
        { al_free(entry.Filters); }
    );
    FilterList.clear();
    almtx_destroy(&FilterLock);

    HrtfList.clear();
    if(HrtfHandle)
        Hrtf_DecRef(HrtfHandle);
    HrtfHandle = nullptr;
    al_free(Hrtf);
    Hrtf = nullptr;

    al_free(Bs2b);
    Bs2b = nullptr;

    al_free(Uhj_Encoder);
    Uhj_Encoder = nullptr;

    bformatdec_free(&AmbiDecoder);
    ambiup_free(&AmbiUp);

    al_free(Stablizer);
    Stablizer = nullptr;

    al_free(Limiter);
    Limiter = nullptr;

    al_free(ChannelDelay[0].Buffer);
    for(ALsizei i{0};i < MAX_OUTPUT_CHANNELS;i++)
    {
        ChannelDelay[i].Gain   = 1.0f;
        ChannelDelay[i].Length = 0;
        ChannelDelay[i].Buffer = nullptr;
    }

    al_free(Dry.Buffer);
    Dry.Buffer = nullptr;
    Dry.NumChannels = 0;
    FOAOut.Buffer = nullptr;
    FOAOut.NumChannels = 0;
    RealOut.Buffer = nullptr;
    RealOut.NumChannels = 0;
}


void ALCdevice_IncRef(ALCdevice *device)
{
    auto ref = IncrementRef(&device->ref);
    TRACEREF("%p increasing refcount to %u\n", device, ref);
}

void ALCdevice_DecRef(ALCdevice *device)
{
    auto ref = DecrementRef(&device->ref);
    TRACEREF("%p decreasing refcount to %u\n", device, ref);
    if(ref == 0) delete device;
}

/* VerifyDevice
 *
 * Checks if the device handle is valid, and increments its ref count if so.
 */
static ALCboolean VerifyDevice(ALCdevice **device)
{
    std::lock_guard<std::recursive_mutex> _{ListLock};
    ALCdevice *tmpDevice{DeviceList.load()};
    while(tmpDevice)
    {
        if(tmpDevice == *device)
        {
            ALCdevice_IncRef(tmpDevice);
            return ALC_TRUE;
        }
        tmpDevice = ATOMIC_LOAD(&tmpDevice->next, almemory_order_relaxed);
    }

    *device = nullptr;
    return ALC_FALSE;
}


/* InitContext
 *
 * Initializes context fields
 */
static ALvoid InitContext(ALCcontext *Context)
{
    ALlistener &listener = Context->Listener;
    struct ALeffectslotArray *auxslots;

    //Validate Context
    almtx_init(&Context->PropLock, almtx_plain);
    almtx_init(&Context->SourceLock, almtx_plain);
    almtx_init(&Context->EffectSlotLock, almtx_plain);

    if(Context->DefaultSlot)
    {
        auxslots = static_cast<ALeffectslotArray*>(al_calloc(DEF_ALIGN,
            FAM_SIZE(struct ALeffectslotArray, slot, 1)));
        auxslots->count = 1;
        auxslots->slot[0] = Context->DefaultSlot;
    }
    else
    {
        auxslots = static_cast<ALeffectslotArray*>(al_calloc(DEF_ALIGN,
            sizeof(struct ALeffectslotArray)));
        auxslots->count = 0;
    }
    ATOMIC_INIT(&Context->ActiveAuxSlots, auxslots);

    //Set globals
    Context->mDistanceModel = DistanceModel::Default;
    Context->SourceDistanceModel = AL_FALSE;
    Context->DopplerFactor = 1.0f;
    Context->DopplerVelocity = 1.0f;
    Context->SpeedOfSound = SPEEDOFSOUNDMETRESPERSEC;
    Context->MetersPerUnit = AL_DEFAULT_METERS_PER_UNIT;
    ATOMIC_INIT(&Context->PropsClean, AL_TRUE);
    ATOMIC_INIT(&Context->DeferUpdates, AL_FALSE);
    alsem_init(&Context->EventSem, 0);
    almtx_init(&Context->EventCbLock, almtx_plain);

    Context->ExtensionList = alExtList;


    listener.Params.Matrix = aluMatrixf::Identity;
    aluVectorSet(&listener.Params.Velocity, 0.0f, 0.0f, 0.0f, 0.0f);
    listener.Params.Gain = listener.Gain;
    listener.Params.MetersPerUnit = Context->MetersPerUnit;
    listener.Params.DopplerFactor = Context->DopplerFactor;
    listener.Params.SpeedOfSound = Context->SpeedOfSound * Context->DopplerVelocity;
    listener.Params.ReverbSpeedOfSound = listener.Params.SpeedOfSound *
                                         listener.Params.MetersPerUnit;
    listener.Params.SourceDistanceModel = Context->SourceDistanceModel;
    listener.Params.mDistanceModel = Context->mDistanceModel;


    Context->AsyncEvents = ll_ringbuffer_create(63, sizeof(AsyncEvent), false);
    StartEventThrd(Context);
}


/* ALCcontext_struct::~ALCcontext_struct()
 *
 * Cleans up the context, and destroys any remaining objects the app failed to
 * delete. Called once there's no more references on the context.
 */
ALCcontext_struct::~ALCcontext_struct()
{
    TRACE("%p\n", this);

    struct ALcontextProps *cprops{Update.load(std::memory_order_relaxed)};
    if(cprops)
    {
        TRACE("Freed unapplied context update %p\n", cprops);
        al_free(cprops);
    }
    size_t count{0};
    cprops = FreeContextProps.load(std::memory_order_acquire);
    while(cprops)
    {
        struct ALcontextProps *next{cprops->next.load(std::memory_order_relaxed)};
        al_free(cprops);
        cprops = next;
        ++count;
    }
    TRACE("Freed " SZFMT " context property object%s\n", count, (count==1)?"":"s");

    delete DefaultSlot;
    DefaultSlot = nullptr;

    al_free(ActiveAuxSlots.exchange(nullptr, std::memory_order_relaxed));

    ReleaseALSources(this);
    std::for_each(SourceList.begin(), SourceList.end(),
        [](const SourceSubList &entry) noexcept -> void
        { al_free(entry.Sources); }
    );
    SourceList.clear();
    NumSources = 0;
    almtx_destroy(&SourceLock);

    count = 0;
    struct ALeffectslotProps *eprops{FreeEffectslotProps.load(std::memory_order_acquire)};
    while(eprops)
    {
        struct ALeffectslotProps *next{eprops->next.load(std::memory_order_relaxed)};
        if(eprops->State) ALeffectState_DecRef(eprops->State);
        al_free(eprops);
        eprops = next;
        ++count;
    }
    TRACE("Freed " SZFMT " AuxiliaryEffectSlot property object%s\n", count, (count==1)?"":"s");

    ReleaseALAuxiliaryEffectSlots(this);
    EffectSlotList.clear();
    almtx_destroy(&EffectSlotLock);

    count = 0;
    struct ALvoiceProps *vprops{FreeVoiceProps.load(std::memory_order_acquire)};
    while(vprops)
    {
        struct ALvoiceProps *next{vprops->next.load(std::memory_order_relaxed)};
        al_free(vprops);
        vprops = next;
        ++count;
    }
    TRACE("Freed " SZFMT " voice property object%s\n", count, (count==1)?"":"s");

    for(ALsizei i{0};i < VoiceCount;i++)
        DeinitVoice(Voices[i]);
    al_free(Voices);
    Voices = nullptr;
    VoiceCount = 0;
    MaxVoices = 0;

    struct ALlistenerProps *lprops{Listener.Update.load(std::memory_order_relaxed)};
    if(lprops)
    {
        TRACE("Freed unapplied listener update %p\n", lprops);
        al_free(lprops);
    }
    count = 0;
    lprops = FreeListenerProps.load(std::memory_order_acquire);
    while(lprops)
    {
        struct ALlistenerProps *next{lprops->next.load(std::memory_order_relaxed)};
        al_free(lprops);
        lprops = next;
        ++count;
    }
    TRACE("Freed " SZFMT " listener property object%s\n", count, (count==1)?"":"s");

    almtx_destroy(&EventCbLock);
    alsem_destroy(&EventSem);

    ll_ringbuffer_free(AsyncEvents);
    AsyncEvents = nullptr;

    almtx_destroy(&PropLock);

    ALCdevice_DecRef(Device);
}

/* ReleaseContext
 *
 * Removes the context reference from the given device and removes it from
 * being current on the running thread or globally. Returns true if other
 * contexts still exist on the device.
 */
static bool ReleaseContext(ALCcontext *context, ALCdevice *device)
{
    ALCcontext *origctx, *newhead;
    bool ret = true;

    if(LocalContext.get() == context)
    {
        WARN("%p released while current on thread\n", context);
        LocalContext.set(nullptr);
        ALCcontext_DecRef(context);
    }

    origctx = context;
    if(GlobalContext.compare_exchange_strong(origctx, nullptr))
        ALCcontext_DecRef(context);

    V0(device->Backend,lock)();
    origctx = context;
    newhead = ATOMIC_LOAD(&context->next, almemory_order_relaxed);
    if(!device->ContextList.compare_exchange_strong(origctx, newhead))
    {
        ALCcontext *list;
        do {
            /* origctx is what the desired context failed to match. Try
             * swapping out the next one in the list.
             */
            list = origctx;
            origctx = context;
        } while(!list->next.compare_exchange_strong(origctx, newhead));
    }
    else
        ret = !!newhead;
    V0(device->Backend,unlock)();

    /* Make sure the context is finished and no longer processing in the mixer
     * before sending the message queue kill event. The backend's lock does
     * this, although waiting for a non-odd mix count would work too.
     */

    StopEventThrd(context);

    ALCcontext_DecRef(context);
    return ret;
}

static void ALCcontext_IncRef(ALCcontext *context)
{
    auto ref = IncrementRef(&context->ref);
    TRACEREF("%p increasing refcount to %u\n", context, ref);
}

void ALCcontext_DecRef(ALCcontext *context)
{
    auto ref = DecrementRef(&context->ref);
    TRACEREF("%p decreasing refcount to %u\n", context, ref);
    if(ref == 0) delete context;
}

static void ReleaseThreadCtx(ALCcontext *context)
{
    auto ref = DecrementRef(&context->ref);
    TRACEREF("%p decreasing refcount to %u\n", context, ref);
    ERR("Context %p current for thread being destroyed, possible leak!\n", context);
}

/* VerifyContext
 *
 * Checks that the given context is valid, and increments its reference count.
 */
static ALCboolean VerifyContext(ALCcontext **context)
{
    std::lock_guard<std::recursive_mutex> _{ListLock};
    ALCdevice *dev{DeviceList.load()};
    while(dev)
    {
        ALCcontext *ctx = ATOMIC_LOAD(&dev->ContextList, almemory_order_acquire);
        while(ctx)
        {
            if(ctx == *context)
            {
                ALCcontext_IncRef(ctx);
                return ALC_TRUE;
            }
            ctx = ATOMIC_LOAD(&ctx->next, almemory_order_relaxed);
        }
        dev = ATOMIC_LOAD(&dev->next, almemory_order_relaxed);
    }

    *context = nullptr;
    return ALC_FALSE;
}


/* GetContextRef
 *
 * Returns the currently active context for this thread, and adds a reference
 * without locking it.
 */
ALCcontext *GetContextRef(void)
{
    ALCcontext *context{LocalContext.get()};
    if(context)
        ALCcontext_IncRef(context);
    else
    {
        std::lock_guard<std::recursive_mutex> _{ListLock};
        context = GlobalContext.load(std::memory_order_acquire);
        if(context) ALCcontext_IncRef(context);
    }

    return context;
}


void AllocateVoices(ALCcontext *context, ALsizei num_voices, ALsizei old_sends)
{
    ALCdevice *device = context->Device;
    ALsizei num_sends = device->NumAuxSends;
    struct ALvoiceProps *props;
    size_t sizeof_props;
    size_t sizeof_voice;
    ALvoice **voices;
    ALvoice *voice;
    ALsizei v = 0;
    size_t size;

    if(num_voices == context->MaxVoices && num_sends == old_sends)
        return;

    /* Allocate the voice pointers, voices, and the voices' stored source
     * property set (including the dynamically-sized Send[] array) in one
     * chunk.
     */
    sizeof_voice = RoundUp(FAM_SIZE(ALvoice, Send, num_sends), 16);
    sizeof_props = RoundUp(FAM_SIZE(struct ALvoiceProps, Send, num_sends), 16);
    size = sizeof(ALvoice*) + sizeof_voice + sizeof_props;

    voices = static_cast<ALvoice**>(al_calloc(16, RoundUp(size*num_voices, 16)));
    /* The voice and property objects are stored interleaved since they're
     * paired together.
     */
    voice = (ALvoice*)((char*)voices + RoundUp(num_voices*sizeof(ALvoice*), 16));
    props = (struct ALvoiceProps*)((char*)voice + sizeof_voice);

    if(context->Voices)
    {
        const ALsizei v_count = mini(context->VoiceCount, num_voices);
        const ALsizei s_count = mini(old_sends, num_sends);

        for(;v < v_count;v++)
        {
            ALvoice *old_voice = context->Voices[v];
            ALsizei i;

            /* Copy the old voice data and source property set to the new
             * storage.
             */
            memcpy(voice, old_voice, sizeof(*voice));
            for(i = 0;i < s_count;i++)
                voice->Send[i] = old_voice->Send[i];
            
            memcpy(props, old_voice->Props, sizeof(*props));
            for(i = 0;i < s_count;i++)
                props->Send[i] = old_voice->Props->Send[i];

            /* Set this voice's property set pointer and voice reference. */
            voice->Props = props;
            voices[v] = voice;

            /* Increment pointers to the next storage space. */
            voice = (ALvoice*)((char*)props + sizeof_props);
            props = (struct ALvoiceProps*)((char*)voice + sizeof_voice);
        }
        /* Deinit any left over voices that weren't copied over to the new
         * array. NOTE: If this does anything, v equals num_voices and
         * num_voices is less than VoiceCount, so the following loop won't do
         * anything.
         */
        for(;v < context->VoiceCount;v++)
            DeinitVoice(context->Voices[v]);
    }
    /* Finish setting the voices' property set pointers and references. */
    for(;v < num_voices;v++)
    {
        ATOMIC_INIT(&voice->Update, static_cast<ALvoiceProps*>(nullptr));

        voice->Props = props;
        voices[v] = voice;

        voice = (ALvoice*)((char*)props + sizeof_props);
        props = (struct ALvoiceProps*)((char*)voice + sizeof_voice);
    }

    al_free(context->Voices);
    context->Voices = voices;
    context->MaxVoices = num_voices;
    context->VoiceCount = mini(context->VoiceCount, num_voices);
}


/************************************************
 * Standard ALC functions
 ************************************************/

/* alcGetError
 *
 * Return last ALC generated error code for the given device
*/
ALC_API ALCenum ALC_APIENTRY alcGetError(ALCdevice *device)
{
    ALCenum errorCode;

    if(VerifyDevice(&device))
    {
        errorCode = device->LastError.exchange(ALC_NO_ERROR);
        ALCdevice_DecRef(device);
    }
    else
        errorCode = LastNullDeviceError.exchange(ALC_NO_ERROR);

    return errorCode;
}


/* alcSuspendContext
 *
 * Suspends updates for the given context
 */
ALC_API ALCvoid ALC_APIENTRY alcSuspendContext(ALCcontext *context)
{
    if(!SuspendDefers)
        return;

    if(!VerifyContext(&context))
        alcSetError(nullptr, ALC_INVALID_CONTEXT);
    else
    {
        ALCcontext_DeferUpdates(context);
        ALCcontext_DecRef(context);
    }
}

/* alcProcessContext
 *
 * Resumes processing updates for the given context
 */
ALC_API ALCvoid ALC_APIENTRY alcProcessContext(ALCcontext *context)
{
    if(!SuspendDefers)
        return;

    if(!VerifyContext(&context))
        alcSetError(nullptr, ALC_INVALID_CONTEXT);
    else
    {
        ALCcontext_ProcessUpdates(context);
        ALCcontext_DecRef(context);
    }
}


/* alcGetString
 *
 * Returns information about the device, and error strings
 */
ALC_API const ALCchar* ALC_APIENTRY alcGetString(ALCdevice *Device, ALCenum param)
{
    const ALCchar *value = nullptr;

    switch(param)
    {
    case ALC_NO_ERROR:
        value = alcNoError;
        break;

    case ALC_INVALID_ENUM:
        value = alcErrInvalidEnum;
        break;

    case ALC_INVALID_VALUE:
        value = alcErrInvalidValue;
        break;

    case ALC_INVALID_DEVICE:
        value = alcErrInvalidDevice;
        break;

    case ALC_INVALID_CONTEXT:
        value = alcErrInvalidContext;
        break;

    case ALC_OUT_OF_MEMORY:
        value = alcErrOutOfMemory;
        break;

    case ALC_DEVICE_SPECIFIER:
        value = alcDefaultName;
        break;

    case ALC_ALL_DEVICES_SPECIFIER:
        if(VerifyDevice(&Device))
        {
            value = Device->DeviceName.c_str();
            ALCdevice_DecRef(Device);
        }
        else
        {
            ProbeAllDevicesList();
            value = alcAllDevicesList.c_str();
        }
        break;

    case ALC_CAPTURE_DEVICE_SPECIFIER:
        if(VerifyDevice(&Device))
        {
            value = Device->DeviceName.c_str();
            ALCdevice_DecRef(Device);
        }
        else
        {
            ProbeCaptureDeviceList();
            value = alcCaptureDeviceList.c_str();
        }
        break;

    /* Default devices are always first in the list */
    case ALC_DEFAULT_DEVICE_SPECIFIER:
        value = alcDefaultName;
        break;

    case ALC_DEFAULT_ALL_DEVICES_SPECIFIER:
        if(alcAllDevicesList.empty())
            ProbeAllDevicesList();

        /* Copy first entry as default. */
        alcDefaultAllDevicesSpecifier = alcAllDevicesList.c_str();
        value = alcDefaultAllDevicesSpecifier.c_str();
        break;

    case ALC_CAPTURE_DEFAULT_DEVICE_SPECIFIER:
        if(alcCaptureDeviceList.empty())
            ProbeCaptureDeviceList();

        /* Copy first entry as default. */
        alcCaptureDefaultDeviceSpecifier = alcCaptureDeviceList.c_str();
        value = alcCaptureDefaultDeviceSpecifier.c_str();
        break;

    case ALC_EXTENSIONS:
        if(!VerifyDevice(&Device))
            value = alcNoDeviceExtList;
        else
        {
            value = alcExtensionList;
            ALCdevice_DecRef(Device);
        }
        break;

    case ALC_HRTF_SPECIFIER_SOFT:
        if(!VerifyDevice(&Device))
            alcSetError(nullptr, ALC_INVALID_DEVICE);
        else
        {
            almtx_lock(&Device->BackendLock);
            value = (Device->HrtfHandle ? Device->HrtfName.c_str() : "");
            almtx_unlock(&Device->BackendLock);
            ALCdevice_DecRef(Device);
        }
        break;

    default:
        VerifyDevice(&Device);
        alcSetError(Device, ALC_INVALID_ENUM);
        if(Device) ALCdevice_DecRef(Device);
        break;
    }

    return value;
}


static inline ALCsizei NumAttrsForDevice(ALCdevice *device)
{
    if(device->Type == Capture) return 9;
    if(device->Type != Loopback) return 29;
    if(device->FmtChans == DevFmtAmbi3D)
        return 35;
    return 29;
}

static ALCsizei GetIntegerv(ALCdevice *device, ALCenum param, ALCsizei size, ALCint *values)
{
    ALCsizei i;

    if(size <= 0 || values == nullptr)
    {
        alcSetError(device, ALC_INVALID_VALUE);
        return 0;
    }

    if(!device)
    {
        switch(param)
        {
            case ALC_MAJOR_VERSION:
                values[0] = alcMajorVersion;
                return 1;
            case ALC_MINOR_VERSION:
                values[0] = alcMinorVersion;
                return 1;

            case ALC_ATTRIBUTES_SIZE:
            case ALC_ALL_ATTRIBUTES:
            case ALC_FREQUENCY:
            case ALC_REFRESH:
            case ALC_SYNC:
            case ALC_MONO_SOURCES:
            case ALC_STEREO_SOURCES:
            case ALC_CAPTURE_SAMPLES:
            case ALC_FORMAT_CHANNELS_SOFT:
            case ALC_FORMAT_TYPE_SOFT:
            case ALC_AMBISONIC_LAYOUT_SOFT:
            case ALC_AMBISONIC_SCALING_SOFT:
            case ALC_AMBISONIC_ORDER_SOFT:
            case ALC_MAX_AMBISONIC_ORDER_SOFT:
                alcSetError(nullptr, ALC_INVALID_DEVICE);
                return 0;

            default:
                alcSetError(nullptr, ALC_INVALID_ENUM);
                return 0;
        }
        return 0;
    }

    if(device->Type == Capture)
    {
        switch(param)
        {
            case ALC_ATTRIBUTES_SIZE:
                values[0] = NumAttrsForDevice(device);
                return 1;

            case ALC_ALL_ATTRIBUTES:
                if(size < NumAttrsForDevice(device))
                {
                    alcSetError(device, ALC_INVALID_VALUE);
                    return 0;
                }

                i = 0;
                almtx_lock(&device->BackendLock);
                values[i++] = ALC_MAJOR_VERSION;
                values[i++] = alcMajorVersion;
                values[i++] = ALC_MINOR_VERSION;
                values[i++] = alcMinorVersion;
                values[i++] = ALC_CAPTURE_SAMPLES;
                values[i++] = V0(device->Backend,availableSamples)();
                values[i++] = ALC_CONNECTED;
                values[i++] = ATOMIC_LOAD(&device->Connected, almemory_order_relaxed);
                almtx_unlock(&device->BackendLock);

                values[i++] = 0;
                return i;

            case ALC_MAJOR_VERSION:
                values[0] = alcMajorVersion;
                return 1;
            case ALC_MINOR_VERSION:
                values[0] = alcMinorVersion;
                return 1;

            case ALC_CAPTURE_SAMPLES:
                almtx_lock(&device->BackendLock);
                values[0] = V0(device->Backend,availableSamples)();
                almtx_unlock(&device->BackendLock);
                return 1;

            case ALC_CONNECTED:
                values[0] = ATOMIC_LOAD(&device->Connected, almemory_order_acquire);
                return 1;

            default:
                alcSetError(device, ALC_INVALID_ENUM);
                return 0;
        }
        return 0;
    }

    /* render device */
    switch(param)
    {
        case ALC_ATTRIBUTES_SIZE:
            values[0] = NumAttrsForDevice(device);
            return 1;

        case ALC_ALL_ATTRIBUTES:
            if(size < NumAttrsForDevice(device))
            {
                alcSetError(device, ALC_INVALID_VALUE);
                return 0;
            }

            i = 0;
            almtx_lock(&device->BackendLock);
            values[i++] = ALC_MAJOR_VERSION;
            values[i++] = alcMajorVersion;
            values[i++] = ALC_MINOR_VERSION;
            values[i++] = alcMinorVersion;
            values[i++] = ALC_EFX_MAJOR_VERSION;
            values[i++] = alcEFXMajorVersion;
            values[i++] = ALC_EFX_MINOR_VERSION;
            values[i++] = alcEFXMinorVersion;

            values[i++] = ALC_FREQUENCY;
            values[i++] = device->Frequency;
            if(device->Type != Loopback)
            {
                values[i++] = ALC_REFRESH;
                values[i++] = device->Frequency / device->UpdateSize;

                values[i++] = ALC_SYNC;
                values[i++] = ALC_FALSE;
            }
            else
            {
                if(device->FmtChans == DevFmtAmbi3D)
                {
                    values[i++] = ALC_AMBISONIC_LAYOUT_SOFT;
                    values[i++] = device->mAmbiLayout;

                    values[i++] = ALC_AMBISONIC_SCALING_SOFT;
                    values[i++] = device->mAmbiScale;

                    values[i++] = ALC_AMBISONIC_ORDER_SOFT;
                    values[i++] = device->mAmbiOrder;
                }

                values[i++] = ALC_FORMAT_CHANNELS_SOFT;
                values[i++] = device->FmtChans;

                values[i++] = ALC_FORMAT_TYPE_SOFT;
                values[i++] = device->FmtType;
            }

            values[i++] = ALC_MONO_SOURCES;
            values[i++] = device->NumMonoSources;

            values[i++] = ALC_STEREO_SOURCES;
            values[i++] = device->NumStereoSources;

            values[i++] = ALC_MAX_AUXILIARY_SENDS;
            values[i++] = device->NumAuxSends;

            values[i++] = ALC_HRTF_SOFT;
            values[i++] = (device->HrtfHandle ? ALC_TRUE : ALC_FALSE);

            values[i++] = ALC_HRTF_STATUS_SOFT;
            values[i++] = device->HrtfStatus;

            values[i++] = ALC_OUTPUT_LIMITER_SOFT;
            values[i++] = device->Limiter ? ALC_TRUE : ALC_FALSE;

            values[i++] = ALC_MAX_AMBISONIC_ORDER_SOFT;
            values[i++] = MAX_AMBI_ORDER;
            almtx_unlock(&device->BackendLock);

            values[i++] = 0;
            return i;

        case ALC_MAJOR_VERSION:
            values[0] = alcMajorVersion;
            return 1;

        case ALC_MINOR_VERSION:
            values[0] = alcMinorVersion;
            return 1;

        case ALC_EFX_MAJOR_VERSION:
            values[0] = alcEFXMajorVersion;
            return 1;

        case ALC_EFX_MINOR_VERSION:
            values[0] = alcEFXMinorVersion;
            return 1;

        case ALC_FREQUENCY:
            values[0] = device->Frequency;
            return 1;

        case ALC_REFRESH:
            if(device->Type == Loopback)
            {
                alcSetError(device, ALC_INVALID_DEVICE);
                return 0;
            }
            almtx_lock(&device->BackendLock);
            values[0] = device->Frequency / device->UpdateSize;
            almtx_unlock(&device->BackendLock);
            return 1;

        case ALC_SYNC:
            if(device->Type == Loopback)
            {
                alcSetError(device, ALC_INVALID_DEVICE);
                return 0;
            }
            values[0] = ALC_FALSE;
            return 1;

        case ALC_FORMAT_CHANNELS_SOFT:
            if(device->Type != Loopback)
            {
                alcSetError(device, ALC_INVALID_DEVICE);
                return 0;
            }
            values[0] = device->FmtChans;
            return 1;

        case ALC_FORMAT_TYPE_SOFT:
            if(device->Type != Loopback)
            {
                alcSetError(device, ALC_INVALID_DEVICE);
                return 0;
            }
            values[0] = device->FmtType;
            return 1;

        case ALC_AMBISONIC_LAYOUT_SOFT:
            if(device->Type != Loopback || device->FmtChans != DevFmtAmbi3D)
            {
                alcSetError(device, ALC_INVALID_DEVICE);
                return 0;
            }
            values[0] = device->mAmbiLayout;
            return 1;

        case ALC_AMBISONIC_SCALING_SOFT:
            if(device->Type != Loopback || device->FmtChans != DevFmtAmbi3D)
            {
                alcSetError(device, ALC_INVALID_DEVICE);
                return 0;
            }
            values[0] = device->mAmbiScale;
            return 1;

        case ALC_AMBISONIC_ORDER_SOFT:
            if(device->Type != Loopback || device->FmtChans != DevFmtAmbi3D)
            {
                alcSetError(device, ALC_INVALID_DEVICE);
                return 0;
            }
            values[0] = device->mAmbiOrder;
            return 1;

        case ALC_MONO_SOURCES:
            values[0] = device->NumMonoSources;
            return 1;

        case ALC_STEREO_SOURCES:
            values[0] = device->NumStereoSources;
            return 1;

        case ALC_MAX_AUXILIARY_SENDS:
            values[0] = device->NumAuxSends;
            return 1;

        case ALC_CONNECTED:
            values[0] = ATOMIC_LOAD(&device->Connected, almemory_order_acquire);
            return 1;

        case ALC_HRTF_SOFT:
            values[0] = (device->HrtfHandle ? ALC_TRUE : ALC_FALSE);
            return 1;

        case ALC_HRTF_STATUS_SOFT:
            values[0] = device->HrtfStatus;
            return 1;

        case ALC_NUM_HRTF_SPECIFIERS_SOFT:
            almtx_lock(&device->BackendLock);
            device->HrtfList.clear();
            device->HrtfList = EnumerateHrtf(device->DeviceName.c_str());
            values[0] = (ALCint)device->HrtfList.size();
            almtx_unlock(&device->BackendLock);
            return 1;

        case ALC_OUTPUT_LIMITER_SOFT:
            values[0] = device->Limiter ? ALC_TRUE : ALC_FALSE;
            return 1;

        case ALC_MAX_AMBISONIC_ORDER_SOFT:
            values[0] = MAX_AMBI_ORDER;
            return 1;

        default:
            alcSetError(device, ALC_INVALID_ENUM);
            return 0;
    }
    return 0;
}

/* alcGetIntegerv
 *
 * Returns information about the device and the version of OpenAL
 */
ALC_API void ALC_APIENTRY alcGetIntegerv(ALCdevice *device, ALCenum param, ALCsizei size, ALCint *values)
{
    VerifyDevice(&device);
    if(size <= 0 || values == nullptr)
        alcSetError(device, ALC_INVALID_VALUE);
    else
        GetIntegerv(device, param, size, values);
    if(device) ALCdevice_DecRef(device);
}

ALC_API void ALC_APIENTRY alcGetInteger64vSOFT(ALCdevice *device, ALCenum pname, ALCsizei size, ALCint64SOFT *values)
{
    ALsizei i;

    VerifyDevice(&device);
    if(size <= 0 || values == nullptr)
        alcSetError(device, ALC_INVALID_VALUE);
    else if(!device || device->Type == Capture)
    {
        std::vector<ALCint> ivals(size);
        size = GetIntegerv(device, pname, size, ivals.data());
        for(i = 0;i < size;i++)
            values[i] = ivals[i];
    }
    else /* render device */
    {
        ClockLatency clock;
        ALuint64 basecount;
        ALuint samplecount;
        ALuint refcount;

        switch(pname)
        {
            case ALC_ATTRIBUTES_SIZE:
                *values = NumAttrsForDevice(device)+4;
                break;

            case ALC_ALL_ATTRIBUTES:
                if(size < NumAttrsForDevice(device)+4)
                    alcSetError(device, ALC_INVALID_VALUE);
                else
                {
                    i = 0;
                    almtx_lock(&device->BackendLock);
                    values[i++] = ALC_FREQUENCY;
                    values[i++] = device->Frequency;

                    if(device->Type != Loopback)
                    {
                        values[i++] = ALC_REFRESH;
                        values[i++] = device->Frequency / device->UpdateSize;

                        values[i++] = ALC_SYNC;
                        values[i++] = ALC_FALSE;
                    }
                    else
                    {
                        if(device->FmtChans == DevFmtAmbi3D)
                        {
                            values[i++] = ALC_AMBISONIC_LAYOUT_SOFT;
                            values[i++] = device->mAmbiLayout;

                            values[i++] = ALC_AMBISONIC_SCALING_SOFT;
                            values[i++] = device->mAmbiScale;

                            values[i++] = ALC_AMBISONIC_ORDER_SOFT;
                            values[i++] = device->mAmbiOrder;
                        }

                        values[i++] = ALC_FORMAT_CHANNELS_SOFT;
                        values[i++] = device->FmtChans;

                        values[i++] = ALC_FORMAT_TYPE_SOFT;
                        values[i++] = device->FmtType;
                    }

                    values[i++] = ALC_MONO_SOURCES;
                    values[i++] = device->NumMonoSources;

                    values[i++] = ALC_STEREO_SOURCES;
                    values[i++] = device->NumStereoSources;

                    values[i++] = ALC_MAX_AUXILIARY_SENDS;
                    values[i++] = device->NumAuxSends;

                    values[i++] = ALC_HRTF_SOFT;
                    values[i++] = (device->HrtfHandle ? ALC_TRUE : ALC_FALSE);

                    values[i++] = ALC_HRTF_STATUS_SOFT;
                    values[i++] = device->HrtfStatus;

                    values[i++] = ALC_OUTPUT_LIMITER_SOFT;
                    values[i++] = device->Limiter ? ALC_TRUE : ALC_FALSE;

                    clock = GetClockLatency(device);
                    values[i++] = ALC_DEVICE_CLOCK_SOFT;
                    values[i++] = clock.ClockTime;

                    values[i++] = ALC_DEVICE_LATENCY_SOFT;
                    values[i++] = clock.Latency;
                    almtx_unlock(&device->BackendLock);

                    values[i++] = 0;
                }
                break;

            case ALC_DEVICE_CLOCK_SOFT:
                almtx_lock(&device->BackendLock);
                do {
                    while(((refcount=ReadRef(&device->MixCount))&1) != 0)
                        althrd_yield();
                    basecount = device->ClockBase;
                    samplecount = device->SamplesDone;
                } while(refcount != ReadRef(&device->MixCount));
                *values = basecount + (samplecount*DEVICE_CLOCK_RES/device->Frequency);
                almtx_unlock(&device->BackendLock);
                break;

            case ALC_DEVICE_LATENCY_SOFT:
                almtx_lock(&device->BackendLock);
                clock = GetClockLatency(device);
                almtx_unlock(&device->BackendLock);
                *values = clock.Latency;
                break;

            case ALC_DEVICE_CLOCK_LATENCY_SOFT:
                if(size < 2)
                    alcSetError(device, ALC_INVALID_VALUE);
                else
                {
                    almtx_lock(&device->BackendLock);
                    clock = GetClockLatency(device);
                    almtx_unlock(&device->BackendLock);
                    values[0] = clock.ClockTime;
                    values[1] = clock.Latency;
                }
                break;

            default:
                std::vector<ALCint> ivals(size);
                size = GetIntegerv(device, pname, size, ivals.data());
                for(i = 0;i < size;i++)
                    values[i] = ivals[i];
                break;
        }
    }
    if(device)
        ALCdevice_DecRef(device);
}


/* alcIsExtensionPresent
 *
 * Determines if there is support for a particular extension
 */
ALC_API ALCboolean ALC_APIENTRY alcIsExtensionPresent(ALCdevice *device, const ALCchar *extName)
{
    ALCboolean bResult = ALC_FALSE;

    VerifyDevice(&device);

    if(!extName)
        alcSetError(device, ALC_INVALID_VALUE);
    else
    {
        size_t len = strlen(extName);
        const char *ptr = (device ? alcExtensionList : alcNoDeviceExtList);
        while(ptr && *ptr)
        {
            if(strncasecmp(ptr, extName, len) == 0 &&
               (ptr[len] == '\0' || isspace(ptr[len])))
            {
                bResult = ALC_TRUE;
                break;
            }
            if((ptr=strchr(ptr, ' ')) != nullptr)
            {
                do {
                    ++ptr;
                } while(isspace(*ptr));
            }
        }
    }
    if(device)
        ALCdevice_DecRef(device);
    return bResult;
}


/* alcGetProcAddress
 *
 * Retrieves the function address for a particular extension function
 */
ALC_API ALCvoid* ALC_APIENTRY alcGetProcAddress(ALCdevice *device, const ALCchar *funcName)
{
    ALCvoid *ptr = nullptr;

    if(!funcName)
    {
        VerifyDevice(&device);
        alcSetError(device, ALC_INVALID_VALUE);
        if(device) ALCdevice_DecRef(device);
    }
    else
    {
        size_t i = 0;
        for(i = 0;i < COUNTOF(alcFunctions);i++)
        {
            if(strcmp(alcFunctions[i].funcName, funcName) == 0)
            {
                ptr = alcFunctions[i].address;
                break;
            }
        }
    }

    return ptr;
}


/* alcGetEnumValue
 *
 * Get the value for a particular ALC enumeration name
 */
ALC_API ALCenum ALC_APIENTRY alcGetEnumValue(ALCdevice *device, const ALCchar *enumName)
{
    ALCenum val = 0;

    if(!enumName)
    {
        VerifyDevice(&device);
        alcSetError(device, ALC_INVALID_VALUE);
        if(device) ALCdevice_DecRef(device);
    }
    else
    {
        size_t i = 0;
        for(i = 0;i < COUNTOF(alcEnumerations);i++)
        {
            if(strcmp(alcEnumerations[i].enumName, enumName) == 0)
            {
                val = alcEnumerations[i].value;
                break;
            }
        }
    }

    return val;
}


/* alcCreateContext
 *
 * Create and attach a context to the given device.
 */
ALC_API ALCcontext* ALC_APIENTRY alcCreateContext(ALCdevice *device, const ALCint *attrList)
{
    ALCcontext *ALContext;
    ALfloat valf;
    ALCenum err;

    /* Explicitly hold the list lock while taking the BackendLock in case the
     * device is asynchronously destropyed, to ensure this new context is
     * properly cleaned up after being made.
     */
    std::unique_lock<std::recursive_mutex> listlock{ListLock};
    if(!VerifyDevice(&device) || device->Type == Capture ||
       !ATOMIC_LOAD(&device->Connected, almemory_order_relaxed))
    {
        listlock.unlock();
        alcSetError(device, ALC_INVALID_DEVICE);
        if(device) ALCdevice_DecRef(device);
        return nullptr;
    }
    almtx_lock(&device->BackendLock);
    listlock.unlock();

    ATOMIC_STORE_SEQ(&device->LastError, ALC_NO_ERROR);

    ALContext = new ALCcontext{device};
    ALCdevice_IncRef(ALContext->Device);

    if((err=UpdateDeviceParams(device, attrList)) != ALC_NO_ERROR)
    {
        almtx_unlock(&device->BackendLock);

        delete ALContext;
        ALContext = nullptr;

        alcSetError(device, err);
        if(err == ALC_INVALID_DEVICE)
        {
            V0(device->Backend,lock)();
            aluHandleDisconnect(device, "Device update failure");
            V0(device->Backend,unlock)();
        }
        ALCdevice_DecRef(device);
        return nullptr;
    }
    AllocateVoices(ALContext, 256, device->NumAuxSends);

    if(DefaultEffect.type != AL_EFFECT_NULL && device->Type == Playback)
    {
        ALContext->DefaultSlot = new ALeffectslot{};
        if(InitEffectSlot(ALContext->DefaultSlot) == AL_NO_ERROR)
            aluInitEffectPanning(ALContext->DefaultSlot);
        else
        {
            delete ALContext->DefaultSlot;
            ALContext->DefaultSlot = nullptr;
            ERR("Failed to initialize the default effect slot\n");
        }
    }

    InitContext(ALContext);

    if(ConfigValueFloat(device->DeviceName.c_str(), nullptr, "volume-adjust", &valf))
    {
        if(!std::isfinite(valf))
            ERR("volume-adjust must be finite: %f\n", valf);
        else
        {
            ALfloat db = clampf(valf, -24.0f, 24.0f);
            if(db != valf)
                WARN("volume-adjust clamped: %f, range: +/-%f\n", valf, 24.0f);
            ALContext->GainBoost = std::pow(10.0f, db/20.0f);
            TRACE("volume-adjust gain: %f\n", ALContext->GainBoost);
        }
    }
    UpdateListenerProps(ALContext);

    {
        ALCcontext *head = ATOMIC_LOAD_SEQ(&device->ContextList);
        do {
            ATOMIC_STORE(&ALContext->next, head, almemory_order_relaxed);
        } while(!device->ContextList.compare_exchange_weak(head, ALContext));
    }
    almtx_unlock(&device->BackendLock);

    if(ALContext->DefaultSlot)
    {
        if(InitializeEffect(ALContext, ALContext->DefaultSlot, &DefaultEffect) == AL_NO_ERROR)
            UpdateEffectSlotProps(ALContext->DefaultSlot, ALContext);
        else
            ERR("Failed to initialize the default effect\n");
    }

    ALCdevice_DecRef(device);

    TRACE("Created context %p\n", ALContext);
    return ALContext;
}

/* alcDestroyContext
 *
 * Remove a context from its device
 */
ALC_API ALCvoid ALC_APIENTRY alcDestroyContext(ALCcontext *context)
{
    std::unique_lock<std::recursive_mutex> listlock{ListLock};
    if(!VerifyContext(&context))
    {
        listlock.unlock();
        alcSetError(nullptr, ALC_INVALID_CONTEXT);
        return;
    }

    ALCdevice* Device{context->Device};
    if(Device)
    {
        almtx_lock(&Device->BackendLock);
        if(!ReleaseContext(context, Device))
        {
            V0(Device->Backend,stop)();
            Device->Flags &= ~DEVICE_RUNNING;
        }
        almtx_unlock(&Device->BackendLock);
    }
    listlock.unlock();

    ALCcontext_DecRef(context);
}


/* alcGetCurrentContext
 *
 * Returns the currently active context on the calling thread
 */
ALC_API ALCcontext* ALC_APIENTRY alcGetCurrentContext(void)
{
    ALCcontext *Context{LocalContext.get()};
    if(!Context) Context = GlobalContext.load();
    return Context;
}

/* alcGetThreadContext
 *
 * Returns the currently active thread-local context
 */
ALC_API ALCcontext* ALC_APIENTRY alcGetThreadContext(void)
{
    return LocalContext.get();
}


/* alcMakeContextCurrent
 *
 * Makes the given context the active process-wide context, and removes the
 * thread-local context for the calling thread.
 */
ALC_API ALCboolean ALC_APIENTRY alcMakeContextCurrent(ALCcontext *context)
{
    /* context must be valid or nullptr */
    if(context && !VerifyContext(&context))
    {
        alcSetError(nullptr, ALC_INVALID_CONTEXT);
        return ALC_FALSE;
    }
    /* context's reference count is already incremented */
    context = GlobalContext.exchange(context);
    if(context) ALCcontext_DecRef(context);

    if((context=LocalContext.get()) != nullptr)
    {
        LocalContext.set(nullptr);
        ALCcontext_DecRef(context);
    }

    return ALC_TRUE;
}

/* alcSetThreadContext
 *
 * Makes the given context the active context for the current thread
 */
ALC_API ALCboolean ALC_APIENTRY alcSetThreadContext(ALCcontext *context)
{
    /* context must be valid or nullptr */
    if(context && !VerifyContext(&context))
    {
        alcSetError(nullptr, ALC_INVALID_CONTEXT);
        return ALC_FALSE;
    }
    /* context's reference count is already incremented */
    ALCcontext *old{LocalContext.get()};
    LocalContext.set(context);
    if(old) ALCcontext_DecRef(old);

    return ALC_TRUE;
}


/* alcGetContextsDevice
 *
 * Returns the device that a particular context is attached to
 */
ALC_API ALCdevice* ALC_APIENTRY alcGetContextsDevice(ALCcontext *Context)
{
    if(!VerifyContext(&Context))
    {
        alcSetError(nullptr, ALC_INVALID_CONTEXT);
        return nullptr;
    }
    ALCdevice *Device{Context->Device};
    ALCcontext_DecRef(Context);

    return Device;
}


/* alcOpenDevice
 *
 * Opens the named device.
 */
ALC_API ALCdevice* ALC_APIENTRY alcOpenDevice(const ALCchar *deviceName)
{
    DO_INITCONFIG();

    if(!PlaybackBackend.name)
    {
        alcSetError(nullptr, ALC_INVALID_VALUE);
        return nullptr;
    }

    if(deviceName && (!deviceName[0] || strcasecmp(deviceName, alcDefaultName) == 0 || strcasecmp(deviceName, "openal-soft") == 0
#ifdef _WIN32
        /* Some old Windows apps hardcode these expecting OpenAL to use a
         * specific audio API, even when they're not enumerated. Creative's
         * router effectively ignores them too.
         */
        || strcasecmp(deviceName, "DirectSound3D") == 0 || strcasecmp(deviceName, "DirectSound") == 0
        || strcasecmp(deviceName, "MMSYSTEM") == 0
#endif
    ))
        deviceName = nullptr;

    auto device = new ALCdevice{Playback};

    //Set output format
    device->FmtChans = DevFmtChannelsDefault;
    device->FmtType = DevFmtTypeDefault;
    device->Frequency = DEFAULT_OUTPUT_RATE;
    device->IsHeadphones = AL_FALSE;
    device->mAmbiLayout = AmbiLayout_Default;
    device->mAmbiScale = AmbiNorm_Default;
    device->LimiterState = ALC_TRUE;
    device->NumUpdates = 3;
    device->UpdateSize = 1024;

    device->SourcesMax = 256;
    device->AuxiliaryEffectSlotMax = 64;
    device->NumAuxSends = DEFAULT_SENDS;

    const ALCchar *fmt{};
    if(ConfigValueStr(deviceName, nullptr, "channels", &fmt))
    {
        static constexpr struct ChannelMap {
            const char name[16];
            enum DevFmtChannels chans;
            ALsizei order;
        } chanlist[] = {
            { "mono",       DevFmtMono,   0 },
            { "stereo",     DevFmtStereo, 0 },
            { "quad",       DevFmtQuad,   0 },
            { "surround51", DevFmtX51,    0 },
            { "surround61", DevFmtX61,    0 },
            { "surround71", DevFmtX71,    0 },
            { "surround51rear", DevFmtX51Rear, 0 },
            { "ambi1", DevFmtAmbi3D, 1 },
            { "ambi2", DevFmtAmbi3D, 2 },
            { "ambi3", DevFmtAmbi3D, 3 },
        };

        auto iter = std::find_if(std::begin(chanlist), std::end(chanlist),
            [fmt](const ChannelMap &entry) -> bool
            { return strcasecmp(entry.name, fmt) == 0; }
        );
        if(iter == std::end(chanlist))
            ERR("Unsupported channels: %s\n", fmt);
        else
        {
            device->FmtChans = iter->chans;
            device->mAmbiOrder = iter->order;
            device->Flags |= DEVICE_CHANNELS_REQUEST;
        }
    }
    if(ConfigValueStr(deviceName, nullptr, "sample-type", &fmt))
    {
        static constexpr struct TypeMap {
            const char name[16];
            enum DevFmtType type;
        } typelist[] = {
            { "int8",    DevFmtByte   },
            { "uint8",   DevFmtUByte  },
            { "int16",   DevFmtShort  },
            { "uint16",  DevFmtUShort },
            { "int32",   DevFmtInt    },
            { "uint32",  DevFmtUInt   },
            { "float32", DevFmtFloat  },
        };

        auto iter = std::find_if(std::begin(typelist), std::end(typelist),
            [fmt](const TypeMap &entry) -> bool
            { return strcasecmp(entry.name, fmt) == 0; }
        );
        if(iter == std::end(typelist))
            ERR("Unsupported sample-type: %s\n", fmt);
        else
        {
            device->FmtType = iter->type;
            device->Flags |= DEVICE_SAMPLE_TYPE_REQUEST;
        }
    }

    if(ConfigValueUInt(deviceName, nullptr, "frequency", &device->Frequency))
    {
        device->Flags |= DEVICE_FREQUENCY_REQUEST;
        if(device->Frequency < MIN_OUTPUT_RATE)
            ERR("%uhz request clamped to %uhz minimum\n", device->Frequency, MIN_OUTPUT_RATE);
        device->Frequency = maxu(device->Frequency, MIN_OUTPUT_RATE);
    }

    ConfigValueUInt(deviceName, nullptr, "periods", &device->NumUpdates);
    device->NumUpdates = clampu(device->NumUpdates, 2, 16);

    ConfigValueUInt(deviceName, nullptr, "period_size", &device->UpdateSize);
    device->UpdateSize = clampu(device->UpdateSize, 64, 8192);
    if((CPUCapFlags&(CPU_CAP_SSE|CPU_CAP_NEON)) != 0)
        device->UpdateSize = (device->UpdateSize+3)&~3;

    ConfigValueUInt(deviceName, nullptr, "sources", &device->SourcesMax);
    if(device->SourcesMax == 0) device->SourcesMax = 256;

    ConfigValueUInt(deviceName, nullptr, "slots", &device->AuxiliaryEffectSlotMax);
    if(device->AuxiliaryEffectSlotMax == 0) device->AuxiliaryEffectSlotMax = 64;
    else device->AuxiliaryEffectSlotMax = minu(device->AuxiliaryEffectSlotMax, INT_MAX);

    if(ConfigValueInt(deviceName, nullptr, "sends", &device->NumAuxSends))
        device->NumAuxSends = clampi(
            DEFAULT_SENDS, 0, clampi(device->NumAuxSends, 0, MAX_SENDS)
        );

    device->NumStereoSources = 1;
    device->NumMonoSources = device->SourcesMax - device->NumStereoSources;

    device->Backend = PlaybackBackend.getFactory().createBackend(device, ALCbackend_Playback);
    if(!device->Backend)
    {
        delete device;
        alcSetError(nullptr, ALC_OUT_OF_MEMORY);
        return nullptr;
    }

    // Find a playback device to open
    ALCenum err{V(device->Backend,open)(deviceName)};
    if(err != ALC_NO_ERROR)
    {
        delete device;
        alcSetError(nullptr, err);
        return nullptr;
    }

    if(ConfigValueStr(device->DeviceName.c_str(), nullptr, "ambi-format", &fmt))
    {
        if(strcasecmp(fmt, "fuma") == 0)
        {
            device->mAmbiLayout = AmbiLayout_FuMa;
            device->mAmbiScale = AmbiNorm_FuMa;
        }
        else if(strcasecmp(fmt, "acn+sn3d") == 0)
        {
            device->mAmbiLayout = AmbiLayout_ACN;
            device->mAmbiScale = AmbiNorm_SN3D;
        }
        else if(strcasecmp(fmt, "acn+n3d") == 0)
        {
            device->mAmbiLayout = AmbiLayout_ACN;
            device->mAmbiScale = AmbiNorm_N3D;
        }
        else
            ERR("Unsupported ambi-format: %s\n", fmt);
    }

    {
        ALCdevice *head{DeviceList.load()};
        do {
            ATOMIC_STORE(&device->next, head, almemory_order_relaxed);
        } while(!DeviceList.compare_exchange_weak(head, device));
    }

    TRACE("Created device %p, \"%s\"\n", device, device->DeviceName.c_str());
    return device;
}

/* alcCloseDevice
 *
 * Closes the given device.
 */
ALC_API ALCboolean ALC_APIENTRY alcCloseDevice(ALCdevice *device)
{
    std::unique_lock<std::recursive_mutex> listlock{ListLock};
    ALCdevice *iter{DeviceList.load()};
    do {
        if(iter == device)
            break;
        iter = ATOMIC_LOAD(&iter->next, almemory_order_relaxed);
    } while(iter != nullptr);
    if(!iter || iter->Type == Capture)
    {
        alcSetError(iter, ALC_INVALID_DEVICE);
        return ALC_FALSE;
    }
    almtx_lock(&device->BackendLock);

    ALCdevice *origdev{device};
    ALCdevice *nextdev{ATOMIC_LOAD(&device->next, almemory_order_relaxed)};
    if(!DeviceList.compare_exchange_strong(origdev, nextdev))
    {
        ALCdevice *list;
        do {
            list = origdev;
            origdev = device;
        } while(!list->next.compare_exchange_strong(origdev, nextdev));
    }
    listlock.unlock();

    ALCcontext *ctx{ATOMIC_LOAD_SEQ(&device->ContextList)};
    while(ctx != nullptr)
    {
        ALCcontext *next = ATOMIC_LOAD(&ctx->next, almemory_order_relaxed);
        WARN("Releasing context %p\n", ctx);
        ReleaseContext(ctx, device);
        ctx = next;
    }
    if((device->Flags&DEVICE_RUNNING))
        V0(device->Backend,stop)();
    device->Flags &= ~DEVICE_RUNNING;
    almtx_unlock(&device->BackendLock);

    ALCdevice_DecRef(device);

    return ALC_TRUE;
}


/************************************************
 * ALC capture functions
 ************************************************/
ALC_API ALCdevice* ALC_APIENTRY alcCaptureOpenDevice(const ALCchar *deviceName, ALCuint frequency, ALCenum format, ALCsizei samples)
{
    DO_INITCONFIG();

    if(!CaptureBackend.name)
    {
        alcSetError(nullptr, ALC_INVALID_VALUE);
        return nullptr;
    }

    if(samples <= 0)
    {
        alcSetError(nullptr, ALC_INVALID_VALUE);
        return nullptr;
    }

    if(deviceName && (!deviceName[0] || strcasecmp(deviceName, alcDefaultName) == 0 || strcasecmp(deviceName, "openal-soft") == 0))
        deviceName = nullptr;

    auto device = new ALCdevice{Capture};

    device->Frequency = frequency;
    device->Flags |= DEVICE_FREQUENCY_REQUEST;

    if(DecomposeDevFormat(format, &device->FmtChans, &device->FmtType) == AL_FALSE)
    {
        delete device;
        alcSetError(nullptr, ALC_INVALID_ENUM);
        return nullptr;
    }
    device->Flags |= DEVICE_CHANNELS_REQUEST | DEVICE_SAMPLE_TYPE_REQUEST;
    device->IsHeadphones = AL_FALSE;
    device->mAmbiOrder = 0;
    device->mAmbiLayout = AmbiLayout_Default;
    device->mAmbiScale = AmbiNorm_Default;

    device->UpdateSize = samples;
    device->NumUpdates = 1;

    device->Backend = CaptureBackend.getFactory().createBackend(device, ALCbackend_Capture);
    if(!device->Backend)
    {
        delete device;
        alcSetError(nullptr, ALC_OUT_OF_MEMORY);
        return nullptr;
    }

    TRACE("Capture format: %s, %s, %uhz, %u update size x%d\n",
        DevFmtChannelsString(device->FmtChans), DevFmtTypeString(device->FmtType),
        device->Frequency, device->UpdateSize, device->NumUpdates
    );
    ALCenum err{V(device->Backend,open)(deviceName)};
    if(err != ALC_NO_ERROR)
    {
        delete device;
        alcSetError(nullptr, err);
        return nullptr;
    }

    {
        ALCdevice *head{DeviceList.load()};
        do {
            ATOMIC_STORE(&device->next, head, almemory_order_relaxed);
        } while(!DeviceList.compare_exchange_weak(head, device));
    }

    TRACE("Created device %p, \"%s\"\n", device, device->DeviceName.c_str());
    return device;
}

ALC_API ALCboolean ALC_APIENTRY alcCaptureCloseDevice(ALCdevice *device)
{
    std::unique_lock<std::recursive_mutex> listlock{ListLock};

    ALCdevice *iter{DeviceList.load()};
    do {
        if(iter == device)
            break;
        iter = ATOMIC_LOAD(&iter->next, almemory_order_relaxed);
    } while(iter != nullptr);
    if(!iter || iter->Type != Capture)
    {
        alcSetError(iter, ALC_INVALID_DEVICE);
        return ALC_FALSE;
    }

    ALCdevice *origdev{device};
    ALCdevice *nextdev{ATOMIC_LOAD(&device->next, almemory_order_relaxed)};
    if(!DeviceList.compare_exchange_strong(origdev, nextdev))
    {
        ALCdevice *list;
        do {
            list = origdev;
            origdev = device;
        } while(!list->next.compare_exchange_strong(origdev, nextdev));
    }
    listlock.unlock();

    almtx_lock(&device->BackendLock);
    if((device->Flags&DEVICE_RUNNING))
        V0(device->Backend,stop)();
    device->Flags &= ~DEVICE_RUNNING;
    almtx_unlock(&device->BackendLock);

    ALCdevice_DecRef(device);

    return ALC_TRUE;
}

ALC_API void ALC_APIENTRY alcCaptureStart(ALCdevice *device)
{
    if(!VerifyDevice(&device) || device->Type != Capture)
        alcSetError(device, ALC_INVALID_DEVICE);
    else
    {
        almtx_lock(&device->BackendLock);
        if(!ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
            alcSetError(device, ALC_INVALID_DEVICE);
        else if(!(device->Flags&DEVICE_RUNNING))
        {
            if(V0(device->Backend,start)())
                device->Flags |= DEVICE_RUNNING;
            else
            {
                aluHandleDisconnect(device, "Device start failure");
                alcSetError(device, ALC_INVALID_DEVICE);
            }
        }
        almtx_unlock(&device->BackendLock);
    }

    if(device) ALCdevice_DecRef(device);
}

ALC_API void ALC_APIENTRY alcCaptureStop(ALCdevice *device)
{
    if(!VerifyDevice(&device) || device->Type != Capture)
        alcSetError(device, ALC_INVALID_DEVICE);
    else
    {
        almtx_lock(&device->BackendLock);
        if((device->Flags&DEVICE_RUNNING))
            V0(device->Backend,stop)();
        device->Flags &= ~DEVICE_RUNNING;
        almtx_unlock(&device->BackendLock);
    }

    if(device) ALCdevice_DecRef(device);
}

ALC_API void ALC_APIENTRY alcCaptureSamples(ALCdevice *device, ALCvoid *buffer, ALCsizei samples)
{
    if(!VerifyDevice(&device) || device->Type != Capture)
        alcSetError(device, ALC_INVALID_DEVICE);
    else
    {
        ALCenum err = ALC_INVALID_VALUE;

        almtx_lock(&device->BackendLock);
        if(samples >= 0 && V0(device->Backend,availableSamples)() >= (ALCuint)samples)
            err = V(device->Backend,captureSamples)(buffer, samples);
        almtx_unlock(&device->BackendLock);

        if(err != ALC_NO_ERROR)
            alcSetError(device, err);
    }
    if(device) ALCdevice_DecRef(device);
}


/************************************************
 * ALC loopback functions
 ************************************************/

/* alcLoopbackOpenDeviceSOFT
 *
 * Open a loopback device, for manual rendering.
 */
ALC_API ALCdevice* ALC_APIENTRY alcLoopbackOpenDeviceSOFT(const ALCchar *deviceName)
{
    DO_INITCONFIG();

    /* Make sure the device name, if specified, is us. */
    if(deviceName && strcmp(deviceName, alcDefaultName) != 0)
    {
        alcSetError(nullptr, ALC_INVALID_VALUE);
        return nullptr;
    }

    auto device = new ALCdevice{Loopback};

    device->SourcesMax = 256;
    device->AuxiliaryEffectSlotMax = 64;
    device->NumAuxSends = DEFAULT_SENDS;

    //Set output format
    device->NumUpdates = 0;
    device->UpdateSize = 0;

    device->Frequency = DEFAULT_OUTPUT_RATE;
    device->FmtChans = DevFmtChannelsDefault;
    device->FmtType = DevFmtTypeDefault;
    device->IsHeadphones = AL_FALSE;
    device->mAmbiLayout = AmbiLayout_Default;
    device->mAmbiScale = AmbiNorm_Default;

    ConfigValueUInt(nullptr, nullptr, "sources", &device->SourcesMax);
    if(device->SourcesMax == 0) device->SourcesMax = 256;

    ConfigValueUInt(nullptr, nullptr, "slots", &device->AuxiliaryEffectSlotMax);
    if(device->AuxiliaryEffectSlotMax == 0) device->AuxiliaryEffectSlotMax = 64;
    else device->AuxiliaryEffectSlotMax = minu(device->AuxiliaryEffectSlotMax, INT_MAX);

    if(ConfigValueInt(nullptr, nullptr, "sends", &device->NumAuxSends))
        device->NumAuxSends = clampi(
            DEFAULT_SENDS, 0, clampi(device->NumAuxSends, 0, MAX_SENDS)
        );

    device->NumStereoSources = 1;
    device->NumMonoSources = device->SourcesMax - device->NumStereoSources;

    device->Backend = LoopbackBackendFactory::getFactory().createBackend(
        device, ALCbackend_Loopback);
    if(!device->Backend)
    {
        al_free(device);
        alcSetError(nullptr, ALC_OUT_OF_MEMORY);
        return nullptr;
    }

    // Open the "backend"
    V(device->Backend,open)("Loopback");

    {
        ALCdevice *head{DeviceList.load()};
        do {
            ATOMIC_STORE(&device->next, head, almemory_order_relaxed);
        } while(!DeviceList.compare_exchange_weak(head, device));
    }

    TRACE("Created device %p\n", device);
    return device;
}

/* alcIsRenderFormatSupportedSOFT
 *
 * Determines if the loopback device supports the given format for rendering.
 */
ALC_API ALCboolean ALC_APIENTRY alcIsRenderFormatSupportedSOFT(ALCdevice *device, ALCsizei freq, ALCenum channels, ALCenum type)
{
    ALCboolean ret{ALC_FALSE};

    if(!VerifyDevice(&device) || device->Type != Loopback)
        alcSetError(device, ALC_INVALID_DEVICE);
    else if(freq <= 0)
        alcSetError(device, ALC_INVALID_VALUE);
    else
    {
        if(IsValidALCType(type) && IsValidALCChannels(channels) && freq >= MIN_OUTPUT_RATE)
            ret = ALC_TRUE;
    }
    if(device) ALCdevice_DecRef(device);

    return ret;
}

/* alcRenderSamplesSOFT
 *
 * Renders some samples into a buffer, using the format last set by the
 * attributes given to alcCreateContext.
 */
FORCE_ALIGN ALC_API void ALC_APIENTRY alcRenderSamplesSOFT(ALCdevice *device, ALCvoid *buffer, ALCsizei samples)
{
    if(!VerifyDevice(&device) || device->Type != Loopback)
        alcSetError(device, ALC_INVALID_DEVICE);
    else if(samples < 0 || (samples > 0 && buffer == nullptr))
        alcSetError(device, ALC_INVALID_VALUE);
    else
    {
        V0(device->Backend,lock)();
        aluMixData(device, buffer, samples);
        V0(device->Backend,unlock)();
    }
    if(device) ALCdevice_DecRef(device);
}


/************************************************
 * ALC DSP pause/resume functions
 ************************************************/

/* alcDevicePauseSOFT
 *
 * Pause the DSP to stop audio processing.
 */
ALC_API void ALC_APIENTRY alcDevicePauseSOFT(ALCdevice *device)
{
    if(!VerifyDevice(&device) || device->Type != Playback)
        alcSetError(device, ALC_INVALID_DEVICE);
    else
    {
        almtx_lock(&device->BackendLock);
        if((device->Flags&DEVICE_RUNNING))
            V0(device->Backend,stop)();
        device->Flags &= ~DEVICE_RUNNING;
        device->Flags |= DEVICE_PAUSED;
        almtx_unlock(&device->BackendLock);
    }
    if(device) ALCdevice_DecRef(device);
}

/* alcDeviceResumeSOFT
 *
 * Resume the DSP to restart audio processing.
 */
ALC_API void ALC_APIENTRY alcDeviceResumeSOFT(ALCdevice *device)
{
    if(!VerifyDevice(&device) || device->Type != Playback)
        alcSetError(device, ALC_INVALID_DEVICE);
    else
    {
        almtx_lock(&device->BackendLock);
        if((device->Flags&DEVICE_PAUSED))
        {
            device->Flags &= ~DEVICE_PAUSED;
            if(ATOMIC_LOAD_SEQ(&device->ContextList) != nullptr)
            {
                if(V0(device->Backend,start)() != ALC_FALSE)
                    device->Flags |= DEVICE_RUNNING;
                else
                {
                    V0(device->Backend,lock)();
                    aluHandleDisconnect(device, "Device start failure");
                    V0(device->Backend,unlock)();
                    alcSetError(device, ALC_INVALID_DEVICE);
                }
            }
        }
        almtx_unlock(&device->BackendLock);
    }
    if(device) ALCdevice_DecRef(device);
}


/************************************************
 * ALC HRTF functions
 ************************************************/

/* alcGetStringiSOFT
 *
 * Gets a string parameter at the given index.
 */
ALC_API const ALCchar* ALC_APIENTRY alcGetStringiSOFT(ALCdevice *device, ALCenum paramName, ALCsizei index)
{
    const ALCchar *str{nullptr};

    if(!VerifyDevice(&device) || device->Type == Capture)
        alcSetError(device, ALC_INVALID_DEVICE);
    else switch(paramName)
    {
        case ALC_HRTF_SPECIFIER_SOFT:
            if(index >= 0 && (size_t)index < device->HrtfList.size())
                str = device->HrtfList[index].name.c_str();
            else
                alcSetError(device, ALC_INVALID_VALUE);
            break;

        default:
            alcSetError(device, ALC_INVALID_ENUM);
            break;
    }
    if(device) ALCdevice_DecRef(device);

    return str;
}

/* alcResetDeviceSOFT
 *
 * Resets the given device output, using the specified attribute list.
 */
ALC_API ALCboolean ALC_APIENTRY alcResetDeviceSOFT(ALCdevice *device, const ALCint *attribs)
{
    std::unique_lock<std::recursive_mutex> listlock{ListLock};
    if(!VerifyDevice(&device) || device->Type == Capture ||
       !ATOMIC_LOAD(&device->Connected, almemory_order_relaxed))
    {
        listlock.unlock();
        alcSetError(device, ALC_INVALID_DEVICE);
        if(device) ALCdevice_DecRef(device);
        return ALC_FALSE;
    }
    almtx_lock(&device->BackendLock);
    listlock.unlock();

    ALCenum err{UpdateDeviceParams(device, attribs)};
    almtx_unlock(&device->BackendLock);

    if(err != ALC_NO_ERROR)
    {
        alcSetError(device, err);
        if(err == ALC_INVALID_DEVICE)
        {
            V0(device->Backend,lock)();
            aluHandleDisconnect(device, "Device start failure");
            V0(device->Backend,unlock)();
        }
        ALCdevice_DecRef(device);
        return ALC_FALSE;
    }
    ALCdevice_DecRef(device);

    return ALC_TRUE;
}