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#include "pch.h"
extern HMODULE hTier0Module;
IMemAlloc** g_ppMemAllocSingleton;
void LoadTier0Handle()
{
if (!hTier0Module)
hTier0Module = GetModuleHandleA("tier0.dll");
if (!hTier0Module)
return;
g_ppMemAllocSingleton = (IMemAlloc**)GetProcAddress(hTier0Module, "g_pMemAllocSingleton");
}
const int STATIC_ALLOC_SIZE = 4096;
size_t g_iStaticAllocated = 0;
void* g_pLastAllocated = nullptr;
char pStaticAllocBuf[STATIC_ALLOC_SIZE];
// they should never be used here, except in LibraryLoadError?
void* malloc(size_t n)
{
// allocate into static buffer
if (g_iStaticAllocated + n <= STATIC_ALLOC_SIZE)
{
void* ret = pStaticAllocBuf + g_iStaticAllocated;
g_iStaticAllocated += n;
return ret;
}
else
{
// try to fallback to g_pMemAllocSingleton
if (!hTier0Module || !g_ppMemAllocSingleton)
LoadTier0Handle();
if (g_ppMemAllocSingleton && *g_ppMemAllocSingleton)
return (*g_ppMemAllocSingleton)->m_vtable->Alloc(*g_ppMemAllocSingleton, n);
else
throw "Cannot allocate";
}
}
void free(void* p)
{
// if it was allocated into the static buffer, just do nothing, safest way to deal with it
if (p >= pStaticAllocBuf && p <= pStaticAllocBuf + STATIC_ALLOC_SIZE)
return;
if (g_ppMemAllocSingleton && *g_ppMemAllocSingleton)
(*g_ppMemAllocSingleton)->m_vtable->Free(*g_ppMemAllocSingleton, p);
}
void* realloc(void* old_ptr, size_t size)
{
// it was allocated into the static buffer
if (old_ptr >= pStaticAllocBuf && old_ptr <= pStaticAllocBuf + STATIC_ALLOC_SIZE)
{
if (g_pLastAllocated == old_ptr)
{
// nothing was allocated after this
size_t old_size = g_iStaticAllocated - ((size_t)g_pLastAllocated - (size_t)pStaticAllocBuf);
size_t diff = size - old_size;
if (diff > 0)
g_iStaticAllocated += diff;
return old_ptr;
}
else
{
return malloc(size);
}
}
if (g_ppMemAllocSingleton && *g_ppMemAllocSingleton)
return (*g_ppMemAllocSingleton)->m_vtable->Realloc(*g_ppMemAllocSingleton, old_ptr, size);
return nullptr;
}
void* operator new(size_t n) { return malloc(n); }
void operator delete(void* p) { return free(p); }
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