Merge pull request #19 from p0358/main

Big refactor of launching process

1 files changed, 84 insertions, 0 deletions

diff --git a/loader_launcher_proxy/Memory.cpp b/loader_launcher_proxy/Memory.cpp
new file mode 100644
index 00000000..f00c4d96
--- /dev/null
+++ b/loader_launcher_proxy/Memory.cpp
@@ -0,0 +1,84 @@
+#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);
+}