Loading Win32/64 DLLs "manually" without LoadLibrary()

// A very-very basic CRT lib.
#include "MiniCRT.h"

#if MINICRT_ENABLED

#include <intrin.h>
#pragma intrinsic(__movsb)


int __cdecl printf(const char* format, ...)
{
	int len, max_len;
	DWORD written;
	char buf[0x100];
	va_list args;

	va_start(args, format);
	len = wvsprintfA(buf, format, args);
	va_end(args);

	max_len = (int)sizeof(buf)-1;
	len = len < max_len ? len : max_len;
	buf[len] = 0;

	WriteConsoleA(GetStdHandle(STD_OUTPUT_HANDLE), buf, (DWORD)len, &written, NULL);
	return len;
}

void* __cdecl operator new(size_t size)
{
	void* p = LocalAlloc(LMEM_FIXED, (SIZE_T)size);
	ASSERT(p);
	return p;
}

void __cdecl operator delete(void* p)
{
	if (p)
		VERIFY_FALSE(LocalFree((HLOCAL)p));
}



#pragma section(".CRT$XCA",long,read)
#pragma data_seg(push, crtxc, ".CRT$XCA")
CrtInitFunc __static_init_func_array_begin[] = { 0 };
#pragma data_seg(pop, crtxc)

#pragma section(".CRT$XCZ",long,read)
#pragma data_seg(push, crtxc, ".CRT$XCZ")
CrtInitFunc __static_init_func_array_end[] = { 0 };
#pragma data_seg(pop, crtxc)

static void StaticInitialization()
{
	for (CrtInitFunc* pinit_func=__static_init_func_array_begin+1; pinit_func<__static_init_func_array_end; ++pinit_func)
	{
		if (*pinit_func)
			(*pinit_func)();
	}
}

// TODO
static CrtInitFunc* g_AtExit = NULL;
static size_t g_AtExitCapacity = 0;
static size_t g_AtExitCount = 0;

static void StaticDeinitialization()
{
	for (size_t i=g_AtExitCount; i--; )
		g_AtExit[i]();
	delete[] g_AtExit;
}


int __cdecl atexit(CrtInitFunc func)
{
	if (!func)
		return 0;
	if (g_AtExitCount >= g_AtExitCapacity)
	{
		g_AtExitCapacity = g_AtExitCapacity ? g_AtExitCapacity*2 : 1;
		CrtInitFunc* new_atexits = new CrtInitFunc[g_AtExitCapacity];
		if (g_AtExitCount)
		{
			__movsb((unsigned char*)new_atexits, (unsigned char*)g_AtExit, g_AtExitCount*sizeof(CrtInitFunc));
			delete[] g_AtExit;
		}
		g_AtExit = new_atexits;
	}
	g_AtExit[g_AtExitCount++] = func;
	return 0;
}

#if ASSERT_ACTIVE
void __assert(const char* condition, const char* file, int line, const char* function)
{
	printf("%s(%d) in function %s: ASSERTION FAILED: %s\n", file, line, function, condition);
	char buf[0x100];
	wsprintfA(buf, "file: %s\nline: %d\nfunction: %s\n\nASSERT(%s)\n\nYes==break No==Continue", file, line, function, condition);
	if (IDYES == MessageBoxA(NULL, buf, "ASSERTION FAILED!", MB_YESNO|MB_ICONEXCLAMATION))
		__debugbreak();
}
#endif

int __cdecl _purecall()
{
	printf("Pure virtual function call!\n");
	MessageBoxA(NULL, "Pure virtual function call!", "Runtime error!", MB_OK|MB_ICONEXCLAMATION);
	__debugbreak();
	ExitProcess(1);
}

void __cdecl MiniCRTStartup()
{
	StaticInitialization();
}

void __cdecl MiniCRTCleanup()
{
	StaticDeinitialization();
}

BOOL WINAPI MiniCRTDllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
	// With manual DLL loading you can not use DLL_THREAD_ATTACH and DLL_THREAD_DETACH.
	switch (fdwReason)
	{
	case DLL_PROCESS_ATTACH:
		MiniCRTStartup();
		break;
	case DLL_PROCESS_DETACH:
		MiniCRTCleanup();
		break;
	default:
		break;
	}
	return TRUE;
}

#endif