bsnes/nall/memory/pool.hpp

63 lines
1.6 KiB
C++

#pragma once
namespace nall {
namespace memory {
template<unsigned Capacity, unsigned Size>
struct pool_spsc {
signed* list = nullptr;
uint8_t* data = nullptr;
unsigned slot = 0;
pool_spsc() {
list = (signed*)memory::allocate(Capacity * sizeof(signed));
data = (uint8_t*)memory::allocate(Capacity * Size);
for(unsigned n = 0; n < Capacity; n++) list[n] = n;
}
~pool_spsc() {
memory::free(list);
memory::free(data);
}
auto allocate(unsigned size) -> void* {
if(size == 0) return nullptr;
if(size > Size) return memory::allocate(size);
signed offset = list[slot];
if(offset < 0) return memory::allocate(size);
list[slot] = -1;
slot = (slot + 1) % Capacity;
return (void*)(data + offset * Size);
}
auto allocate(unsigned size, uint8_t data) -> void* {
auto result = allocate(size);
memset(result, data, size);
return result;
}
auto resize(void* target, unsigned size) -> void* {
if(target == nullptr) return allocate(size);
signed offset = ((uint8_t*)target - data) / Size;
if(offset < 0 || offset >= Capacity) return memory::resize(target, size);
if(size <= Size) return target;
slot = (slot - 1) % Capacity;
list[slot] = offset;
return memory::allocate(size);
}
auto free(void* target) -> void {
if(target == nullptr) return;
signed offset = ((uint8_t*)target - data) / Size;
if(offset < 0 || offset >= Capacity) return memory::free(target);
slot = (slot - 1) % Capacity;
list[slot] = offset;
}
pool_spsc(const pool_spsc&) = delete;
pool_spsc& operator=(const pool_spsc&) = delete;
};
}
}