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Replace CAtom's bitfield with packed struct #243

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Replace CAtom's bitfield with packed struct #243

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8196ead
Replace CAtom's bitfield with packed struct
frmdstryr Feb 4, 2025
969291a
Invert notifications_enabled bitfield logic to save a write on each C…
frmdstryr Feb 6, 2025
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51 changes: 20 additions & 31 deletions atom/src/catom.h
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Original file line number Diff line number Diff line change
Expand Up @@ -13,26 +13,27 @@


#define MAX_MEMBER_COUNT ( static_cast<uint32_t>( 0xffff ) )
#define SLOT_COUNT_MASK ( static_cast<uint32_t>( 0xffff ) )
#define FLAGS_MASK ( static_cast<uint32_t>( 0xffff0000 ) )
#define NOTIFICATION_BIT ( static_cast<uint32_t>( 1 << 16 ) )
#define GUARD_BIT ( static_cast<uint32_t>( 1 << 17 ) )
#define ATOMREF_BIT ( static_cast<uint32_t>( 1 << 18 ) )
#define FROZEN_BIT ( static_cast<uint32_t>( 1 << 19 ) )
#define catom_cast( o ) ( reinterpret_cast<atom::CAtom*>( o ) )


namespace atom
{


PACK(struct CAtomInfo {
uint16_t slot_count;
bool notifications_enabled: 1;
bool has_guards: 1;
bool has_atomref: 1;
bool is_frozen: 1;
uint16_t reserved: 12;
});

struct CAtom
{
PyObject_HEAD
uint32_t bitfield; // lower 16 == slot count, upper 16 == flags
PyObject** slots;
ObserverPool* observers;
CAtomInfo info;

static PyType_Spec TypeObject_Spec;

Expand All @@ -42,12 +43,12 @@ struct CAtom

uint32_t get_slot_count()
{
return bitfield & SLOT_COUNT_MASK;
return info.slot_count;
}

void set_slot_count( uint32_t count )
void set_slot_count( uint16_t count )
{
bitfield = ( bitfield & FLAGS_MASK ) | ( count & SLOT_COUNT_MASK );
info.slot_count = count;
}

PyObject* get_slot( uint32_t index )
Expand All @@ -65,41 +66,32 @@ struct CAtom

bool get_notifications_enabled()
{
return ( bitfield & NOTIFICATION_BIT ) != 0;
return info.notifications_enabled;
}

void set_notifications_enabled( bool enabled )
{
if( enabled )
bitfield |= NOTIFICATION_BIT;
else
bitfield &= ~NOTIFICATION_BIT;
info.notifications_enabled = enabled;
}

bool has_guards()
{
return ( bitfield & GUARD_BIT ) != 0;
return info.has_guards;
}

void set_has_guards( bool has_guards )
{
if( has_guards )
bitfield |= GUARD_BIT;
else
bitfield &= ~GUARD_BIT;
info.has_guards = has_guards;
}

bool has_atomref()
{
return ( bitfield & ATOMREF_BIT ) != 0;
return info.has_atomref;
}

void set_has_atomref( bool has_ref )
{
if( has_ref )
bitfield |= ATOMREF_BIT;
else
bitfield &= ~ATOMREF_BIT;
info.has_atomref = has_ref;
}

bool has_observers( PyObject* topic )
Expand All @@ -125,15 +117,12 @@ struct CAtom

bool is_frozen()
{
return ( bitfield & FROZEN_BIT ) != 0;
return info.is_frozen;
}

void set_frozen( bool frozen )
{
if( frozen )
bitfield |= FROZEN_BIT;
else
bitfield &= ~FROZEN_BIT;
info.is_frozen = frozen;
}

bool observe( PyObject* topic, PyObject* callback )
Expand Down