Fix memalloc problems (R2Northstar#728)

alloc declarations to work with CRT
implement missing _recalloc_base and _msize

primedev/core/memalloc.cpp

@@ -3,7 +3,7 @@
 
 // TODO: rename to malloc and free after removing statically compiled .libs
 
-extern "C" void* _malloc_base(size_t n)
+void* _malloc_base(size_t n)
 {
 	// allocate into static buffer if g_pMemAllocSingleton isn't initialised
 	if (!g_pMemAllocSingleton)
@@ -17,23 +17,23 @@ extern "C" void* _malloc_base(size_t n)
 	return _malloc_base(n);
 }*/
 
-extern "C" void _free_base(void* p)
+void _free_base(void* p)
 {
 	if (!g_pMemAllocSingleton)
 		TryCreateGlobalMemAlloc();
 
 	g_pMemAllocSingleton->m_vtable->Free(g_pMemAllocSingleton, p);
 }
 
-extern "C" void* _realloc_base(void* oldPtr, size_t size)
+void* _realloc_base(void* oldPtr, size_t size)
 {
 	if (!g_pMemAllocSingleton)
 		TryCreateGlobalMemAlloc();
 
 	return g_pMemAllocSingleton->m_vtable->Realloc(g_pMemAllocSingleton, oldPtr, size);
 }
 
-extern "C" void* _calloc_base(size_t n, size_t size)
+void* _calloc_base(size_t n, size_t size)
 {
 	size_t bytes = n * size;
 	void* memory = _malloc_base(bytes);
@@ -44,7 +44,33 @@ extern "C" void* _calloc_base(size_t n, size_t size)
 	return memory;
 }
 
-extern "C" char* _strdup_base(const char* src)
+void* _recalloc_base(void* const block, size_t const count, size_t const size)
+{
+	if (!block)
+		return _calloc_base(count, size);
+
+	const size_t new_size = count * size;
+	const size_t old_size = _msize(block);
+
+	void* const memory = _realloc_base(block, new_size);
+
+	if (memory && old_size < new_size)
+	{
+		memset(static_cast<char*>(memory) + old_size, 0, new_size - old_size);
+	}
+
+	return memory;
+}
+
+size_t _msize(void* const block)
+{
+	if (!g_pMemAllocSingleton)
+		TryCreateGlobalMemAlloc();
+
+	return g_pMemAllocSingleton->m_vtable->GetSize(g_pMemAllocSingleton, block);
+}
+
+char* _strdup_base(const char* src)
 {
 	char* str;
 	char* p;

primedev/core/memalloc.h

@@ -1,14 +1,18 @@
 #pragma once
 
+#include <malloc.h>
+
 #include "rapidjson/document.h"
 // #include "include/rapidjson/allocators.h"
 
-extern "C" void* _malloc_base(size_t size);
-extern "C" void* _calloc_base(size_t const count, size_t const size);
-extern "C" void* _realloc_base(void* block, size_t size);
-extern "C" void* _recalloc_base(void* const block, size_t const count, size_t const size);
-extern "C" void _free_base(void* const block);
-extern "C" char* _strdup_base(const char* src);
+// The prelude is needed for these to be usable by the CRT
+extern "C" __declspec(noinline) void* __cdecl _malloc_base(size_t const size);
+extern "C" __declspec(noinline) void* __cdecl _calloc_base(size_t const count, size_t const size);
+extern "C" __declspec(noinline) void* __cdecl _realloc_base(void* const block, size_t const size);
+extern "C" __declspec(noinline) void* __cdecl _recalloc_base(void* const block, size_t const count, size_t const size);
+extern "C" __declspec(noinline) void __cdecl _free_base(void* const block);
+extern "C" __declspec(noinline) size_t __cdecl _msize(void* const block);
+extern "C" __declspec(noinline) char* __cdecl _strdup_base(const char* src);
 
 void* operator new(size_t n);
 void operator delete(void* p) noexcept;