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0ad/source/lib/allocators/unique_range.cpp
2011-12-29 02:06:09 +00:00

83 lines
2.3 KiB
C++

#include "precompiled.h"
#include "lib/allocators/unique_range.h"
#include "lib/bits.h" // is_pow2, round_up
#include "lib/sysdep/cpu.h" // cpu_AtomicAdd
#include "lib/sysdep/rtl.h" // rtl_FreeAligned
static void FreeNone(void* UNUSED(pointer), size_t UNUSED(size))
{
// (providing a deleter function for idxDeleterNone avoids
// having to check whether deleters[idxDeleter] == 0)
}
static void FreeAligned(void* pointer, size_t UNUSED(size))
{
return rtl_FreeAligned(pointer);
}
static UniqueRangeDeleter deleters[allocationAlignment] = { FreeNone, FreeAligned };
static IdxDeleter numDeleters = 2;
// NB: callers should skip this if *idxDeleterOut != 0 (avoids the overhead
// of an unnecessary indirect function call)
void RegisterUniqueRangeDeleter(UniqueRangeDeleter deleter, volatile IdxDeleter* idxDeleterOut)
{
ENSURE(deleter);
if(!cpu_CAS(idxDeleterOut, idxDeleterNone, -1)) // not the first call for this deleter
{
// wait until an index has been assigned
while(*idxDeleterOut <= 0)
cpu_Pause();
return;
}
const IdxDeleter idxDeleter = cpu_AtomicAdd(&numDeleters, 1);
ENSURE(idxDeleter < (IdxDeleter)ARRAY_SIZE(deleters));
deleters[idxDeleter] = deleter;
COMPILER_FENCE;
*idxDeleterOut = idxDeleter;
}
NOTHROW_DEFINE void CallUniqueRangeDeleter(void* pointer, size_t size, IdxDeleter idxDeleter)
{
ASSERT(idxDeleter < numDeleters);
// (some deleters do not tolerate null pointers)
if(pointer)
deleters[idxDeleter](pointer, size);
}
UniqueRange AllocateAligned(size_t size, size_t alignment)
{
ENSURE(is_pow2(alignment));
alignment = std::max(alignment, allocationAlignment);
const size_t alignedSize = round_up(size, alignment);
const UniqueRange::pointer p = rtl_AllocateAligned(alignedSize, alignment);
static volatile IdxDeleter idxDeleterAligned;
if(idxDeleterAligned == 0) // (optional optimization)
RegisterUniqueRangeDeleter(FreeAligned, &idxDeleterAligned);
return RVALUE(UniqueRange(p, size, idxDeleterAligned));
}
UniqueRange AllocateVM(size_t size, vm::PageType pageType, int prot)
{
const UniqueRange::pointer p = vm::Allocate(size, pageType, prot);
static volatile IdxDeleter idxDeleter;
if(idxDeleter == 0) // (optional optimization)
RegisterUniqueRangeDeleter(vm::Free, &idxDeleter);
return RVALUE(UniqueRange(p, size, idxDeleter));
}