TeamHepta/SDL
1
0
Fork 0
mirror of https://github.com/libsdl-org/SDL.git synced 2026-03-20 15:51:07 +01:00
Code Issues Packages Projects Releases Wiki Activity

audio: Clean out all the bitshifting.

Browse Source 
Hide the implementation details in something human-readable.
This commit is contained in:
Ryan C. Gordon
2025-08-25 13:06:09 -04:00
parent 01d94ca9de
commit 8f04e4af00
1 changed files with 28 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

59
src/audio/SDL_audio.c
View File

@@ -367,14 +367,28 @@ static SDL_AudioDeviceID AssignAudioDeviceInstanceId(bool recording, bool islogi
bool SDL_IsAudioDevicePhysical(SDL_AudioDeviceID devid)
{
// bit #1 of devid is set for physical devices and unset for logical.
return (devid & (1 << 1)) != 0;
}
bool SDL_IsAudioDeviceLogical(SDL_AudioDeviceID devid)
{
// bit #1 of devid is set for physical devices and unset for logical.
return (devid & (1 << 1)) == 0;
}
bool SDL_IsAudioDevicePlayback(SDL_AudioDeviceID devid)
{
// bit #0 of devid is set for playback devices and unset for recording.
return (devid & (1 << 0)) != 0;
}
bool SDL_IsAudioDeviceRecording(SDL_AudioDeviceID devid)
{
// bit #0 of devid is set for playback devices and unset for recording.
return (devid & (1 << 0)) == 0;
}
static void ObtainPhysicalAudioDeviceObj(SDL_AudioDevice *device) SDL_NO_THREAD_SAFETY_ANALYSIS // !!! FIXMEL SDL_ACQUIRE
{
if (device) {
@@ -405,9 +419,7 @@ static SDL_LogicalAudioDevice *ObtainLogicalAudioDevice(SDL_AudioDeviceID devid,
SDL_AudioDevice *device = NULL;
SDL_LogicalAudioDevice *logdev = NULL;
// bit #1 of devid is set for physical devices and unset for logical.
const bool islogical = !(devid & (1<<1));
if (islogical) { // don't bother looking if it's not a logical device id value.
if (SDL_IsAudioDeviceLogical(devid)) { // don't bother looking if it's not a logical device id value.
SDL_LockRWLockForReading(current_audio.subsystem_rwlock);
SDL_FindInHashTable(current_audio.device_hash_logical, (const void *) (uintptr_t) devid, (const void **) &logdev);
if (logdev) {
@@ -452,9 +464,7 @@ static SDL_AudioDevice *ObtainPhysicalAudioDevice(SDL_AudioDeviceID devid) // !
{
SDL_AudioDevice *device = NULL;
// bit #1 of devid is set for physical devices and unset for logical.
const bool islogical = !(devid & (1<<1));
if (islogical) {
if (SDL_IsAudioDeviceLogical(devid)) {
ObtainLogicalAudioDevice(devid, &device);
} else if (!SDL_GetCurrentAudioDriver()) { // (the `islogical` path, above, checks this in ObtainLogicalAudioDevice.)
SDL_SetError("Audio subsystem is not initialized");
@@ -879,12 +889,8 @@ static bool SDLCALL FindLowestDeviceID(void *userdata, const SDL_HashTable *tabl
{
FindLowestDeviceIDData *data = (FindLowestDeviceIDData *) userdata;
const SDL_AudioDeviceID devid = (SDL_AudioDeviceID) (uintptr_t) key;
// bit #0 of devid is set for playback devices and unset for recording.
// bit #1 of devid is set for physical devices and unset for logical.
const bool devid_recording = !(devid & (1 << 0));
const bool isphysical = !!(devid & (1 << 1));
SDL_assert(isphysical); // should only be iterating device_hash_physical.
if ((devid_recording == data->recording) && (devid < data->highest)) {
SDL_assert(SDL_IsAudioDevicePhysical(devid)); // should only be iterating device_hash_physical.
if ((SDL_IsAudioDeviceRecording(devid) == data->recording) && (devid < data->highest)) {
data->highest = devid;
data->result = (SDL_AudioDevice *) value;
SDL_assert(data->result->instance_id == devid);
@@ -1065,10 +1071,8 @@ bool SDL_InitAudio(const char *driver_name)
static bool SDLCALL DestroyOnePhysicalAudioDevice(void *userdata, const SDL_HashTable *table, const void *key, const void *value)
{
// bit #1 of devid is set for physical devices and unset for logical.
const SDL_AudioDeviceID devid = (SDL_AudioDeviceID) (uintptr_t) key;
const bool isphysical = !!(devid & (1<<1));
SDL_assert(isphysical);
SDL_assert(SDL_IsAudioDevicePhysical(devid)); // should only be iterating device_hash_physical.
SDL_AudioDevice *dev = (SDL_AudioDevice *) value;
SDL_assert(dev->instance_id == devid);
DestroyPhysicalAudioDevice(dev);
@@ -1428,12 +1432,8 @@ static bool SDLCALL CountAudioDevices(void *userdata, const SDL_HashTable *table
{
CountAudioDevicesData *data = (CountAudioDevicesData *) userdata;
const SDL_AudioDeviceID devid = (SDL_AudioDeviceID) (uintptr_t) key;
// bit #0 of devid is set for playback devices and unset for recording.
// bit #1 of devid is set for physical devices and unset for logical.
const bool devid_recording = !(devid & (1<<0));
const bool isphysical = !!(devid & (1<<1));
SDL_assert(isphysical);
if (devid_recording == data->recording) {
SDL_assert(SDL_IsAudioDevicePhysical(devid)); // should only be iterating device_hash_physical.
if (SDL_IsAudioDeviceRecording(devid) == data->recording) {
SDL_assert(data->devs_seen < data->num_devices);
SDL_AudioDevice *device = (SDL_AudioDevice *) value; // this is normally risky, but we hold the subsystem_rwlock here.
const bool zombie = SDL_GetAtomicInt(&device->zombie) != 0;
@@ -1500,9 +1500,7 @@ static bool SDLCALL FindAudioDeviceByCallback(void *userdata, const SDL_HashTabl
{
FindAudioDeviceByCallbackData *data = (FindAudioDeviceByCallbackData *) userdata;
const SDL_AudioDeviceID devid = (SDL_AudioDeviceID) (uintptr_t) key;
// bit #1 of devid is set for physical devices and unset for logical.
const bool isphysical = !!(devid & (1<<1));
SDL_assert(isphysical);
SDL_assert(SDL_IsAudioDevicePhysical(devid)); // should only be iterating device_hash_physical.
SDL_AudioDevice *device = (SDL_AudioDevice *) value;
if (data->callback(device, data->userdata)) { // found it?
data->retval = device;
@@ -1545,13 +1543,14 @@ SDL_AudioDevice *SDL_FindPhysicalAudioDeviceByHandle(void *handle)
const char *SDL_GetAudioDeviceName(SDL_AudioDeviceID devid)
{
// bit #1 of devid is set for physical devices and unset for logical.
const bool islogical = !(devid & (1<<1));
const char *result = NULL;
const void *vdev = NULL;
if (!SDL_GetCurrentAudioDriver()) {
SDL_SetError("Audio subsystem is not initialized");
} else {
const bool islogical = SDL_IsAudioDeviceLogical(devid);
const void *vdev = NULL;
// This does not call ObtainPhysicalAudioDevice() because the device's name never changes, so
// it doesn't have to lock the whole device. However, just to make sure the device pointer itself
// remains valid (in case the device is unplugged at the wrong moment), we hold the
@@ -1844,8 +1843,7 @@ SDL_AudioDeviceID SDL_OpenAudioDevice(SDL_AudioDeviceID devid, const SDL_AudioSp
// this will let you use a logical device to make a new logical device on the parent physical device. Could be useful?
SDL_AudioDevice *device = NULL;
const bool islogical = (!wants_default && !(devid & (1<<1)));
if (!islogical) {
if ((wants_default || SDL_IsAudioDevicePhysical(devid))) {
device = ObtainPhysicalAudioDeviceDefaultAllowed(devid);
} else {
SDL_LogicalAudioDevice *logdev = ObtainLogicalAudioDevice(devid, &device);
@@ -1982,7 +1980,6 @@ bool SDL_SetAudioPostmixCallback(SDL_AudioDeviceID devid, SDL_AudioPostmixCallba
bool SDL_BindAudioStreams(SDL_AudioDeviceID devid, SDL_AudioStream * const *streams, int num_streams)
{
const bool islogical = !(devid & (1<<1));
SDL_AudioDevice *device = NULL;
SDL_LogicalAudioDevice *logdev = NULL;
bool result = true;
@@ -1993,7 +1990,7 @@ bool SDL_BindAudioStreams(SDL_AudioDeviceID devid, SDL_AudioStream * const *stre
return SDL_InvalidParamError("num_streams");
} else if (!streams) {
return SDL_InvalidParamError("streams");
} else if (!islogical) {
} else if (SDL_IsAudioDevicePhysical(devid)) {
return SDL_SetError("Audio streams are bound to device ids from SDL_OpenAudioDevice, not raw physical devices");
}
@@ -2600,7 +2597,7 @@ void SDL_UpdateAudio(void)
SDL_zero(event);
event.type = i->type;
event.adevice.which = (Uint32) i->devid;
event.adevice.recording = ((i->devid & (1<<0)) == 0); // bit #0 of devid is set for playback devices and unset for recording.
event.adevice.recording = SDL_IsAudioDeviceRecording(i->devid); // bit #0 of devid is set for playback devices and unset for recording.
SDL_PushEvent(&event);
}
SDL_free(i);