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ALSA: A pedantic optimization to avoid a malloc.

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This commit is contained in:
David Reid
2026-01-15 10:45:36 +10:00
parent 1509e9b375
commit dc7f5286ca
1 changed files with 15 additions and 16 deletions
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miniaudio.h
+15 -16
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@@ -28932,7 +28932,7 @@ static ma_result ma_context_enumerate_devices__alsa(ma_context* pContext, ma_enu
static ma_result ma_device_init_by_type__alsa(ma_context* pContext, ma_context_state_alsa* pContextStateALSA, ma_device_state_alsa* pDeviceStateALSA, const ma_device_config_alsa* pDeviceConfigALSA, ma_device_descriptor* pDescriptor, ma_device_type deviceType)
static ma_result ma_device_init_by_type__alsa(ma_context* pContext, ma_context_state_alsa* pContextStateALSA, ma_device_state_alsa* pDeviceStateALSA, const ma_device_config_alsa* pDeviceConfigALSA, ma_device_descriptor* pDescriptor, ma_device_type deviceType, void* pParamsMemory)
{
int resultALSA;
ma_snd_pcm_t* pPCM;
@@ -28945,8 +28945,6 @@ static ma_result ma_device_init_by_type__alsa(ma_context* pContext, ma_context_s
ma_uint32 internalPeriodSizeInFrames;
ma_uint32 internalPeriods;
int openMode;
size_t paramsMemorySize;
void* pParamsMemory; /* One allocation for both hardware and software params. */
ma_snd_pcm_hw_params_t* pHWParams;
ma_snd_pcm_sw_params_t* pSWParams;
const char* pDeviceNames[16];
@@ -28998,14 +28996,6 @@ static ma_result ma_device_init_by_type__alsa(ma_context* pContext, ma_context_s
deviceNameCount = iDeviceName;
/* Allocate memory for our hardware and software params. We do this with a single allocation. They are used independently so we can just alias this allocation. */
paramsMemorySize = ma_max(pContextStateALSA->snd_pcm_hw_params_sizeof(), pContextStateALSA->snd_pcm_sw_params_sizeof());
pParamsMemory = ma_calloc(paramsMemorySize, ma_context_get_allocation_callbacks(pContext));
if (pParamsMemory == NULL) {
return MA_OUT_OF_MEMORY;
}
/* Alias the memory allocation. */
pHWParams = (ma_snd_pcm_hw_params_t*)pParamsMemory;
pSWParams = (ma_snd_pcm_sw_params_t*)pParamsMemory;
@@ -29372,12 +29362,10 @@ static ma_result ma_device_init_by_type__alsa(ma_context* pContext, ma_context_s
pDescriptor->periodSizeInFrames = internalPeriodSizeInFrames;
pDescriptor->periodCount = internalPeriods;
ma_free(pParamsMemory, ma_context_get_allocation_callbacks(pContext));
return MA_SUCCESS;
}
/* Getting here means we failed to initialize the device. */
ma_free(pParamsMemory, ma_context_get_allocation_callbacks(pContext));
return MA_ERROR;
}
@@ -29416,6 +29404,8 @@ static ma_result ma_device_init__alsa(ma_device* pDevice, const void* pDeviceBac
ma_uint32 intermediaryBufferSizePlayback = 0;
size_t pollDescriptorAllocationSize = 0;
size_t intermediaryBufferAllocationSize = 0;
size_t paramsMemorySize;
void* pParamsMemory;
MA_ASSERT(pContextStateALSA != NULL);
@@ -29428,11 +29418,20 @@ static ma_result ma_device_init__alsa(ma_device* pDevice, const void* pDeviceBac
return MA_DEVICE_TYPE_NOT_SUPPORTED;
}
pDeviceStateALSA = (ma_device_state_alsa*)ma_calloc(sizeof(*pDeviceStateALSA), ma_device_get_allocation_callbacks(pDevice));
/*
The memory for hw and sw params are allocated on the heap. We'll do that as part of the device state allocation
so I can obsessively reduce our malloc count by 1. It'll be realloc'd later when we append memory for the pollfd
objects and intermediary buffer so shouldn't be wasteful.
*/
paramsMemorySize = ma_max(pContextStateALSA->snd_pcm_hw_params_sizeof(), pContextStateALSA->snd_pcm_sw_params_sizeof());
pDeviceStateALSA = (ma_device_state_alsa*)ma_calloc(ma_align_64(sizeof(*pDeviceStateALSA)) + paramsMemorySize, ma_device_get_allocation_callbacks(pDevice));
if (pDeviceStateALSA == NULL) {
return MA_OUT_OF_MEMORY;
}
pParamsMemory = ma_offset_ptr(pDeviceStateALSA, ma_align_64(sizeof(*pDeviceStateALSA)));
if (deviceType == ma_device_type_capture || deviceType == ma_device_type_duplex) {
/* Duplex mode must have at least two periods. */
if (deviceType == ma_device_type_duplex) {
@@ -29441,7 +29440,7 @@ static ma_result ma_device_init__alsa(ma_device* pDevice, const void* pDeviceBac
}
}
result = ma_device_init_by_type__alsa(ma_device_get_context(pDevice), pContextStateALSA, pDeviceStateALSA, pDeviceConfigALSA, pDescriptorCapture, ma_device_type_capture);
result = ma_device_init_by_type__alsa(ma_device_get_context(pDevice), pContextStateALSA, pDeviceStateALSA, pDeviceConfigALSA, pDescriptorCapture, ma_device_type_capture, pParamsMemory);
if (result != MA_SUCCESS) {
ma_device_uninit_internal__alsa(pDevice, pDeviceStateALSA);
return result;
@@ -29465,7 +29464,7 @@ static ma_result ma_device_init__alsa(ma_device* pDevice, const void* pDeviceBac
}
}
result = ma_device_init_by_type__alsa(ma_device_get_context(pDevice), pContextStateALSA, pDeviceStateALSA, pDeviceConfigALSA, pDescriptorPlayback, ma_device_type_playback);
result = ma_device_init_by_type__alsa(ma_device_get_context(pDevice), pContextStateALSA, pDeviceStateALSA, pDeviceConfigALSA, pDescriptorPlayback, ma_device_type_playback, pParamsMemory);
if (result != MA_SUCCESS) {
ma_device_uninit_internal__alsa(pDevice, pDeviceStateALSA);
return result;