doohickey to output memory stats at runtime

auxmemorystats.c

/********************************************************************************/
/*	DON'T USE THIS, I REWROTE IT WITH BETTER CODE AND LINUX SUPPORT:			*/
/*	https://github.com/Absolucy/byond-memorystats								*/
/********************************************************************************/

#ifndef __clang__
#error use clang to compile this graaaah
#endif

#include <stdio.h>
#include <string.h>
#include <windows.h>

typedef struct
{
	unsigned int _idc1;
	unsigned short _idc2;
	unsigned char _idc3;
	char str[];
} DMStringData;

typedef struct
{
	DMStringData *data;
} DMString;

typedef DMString* (__stdcall *GetServerMemUsage)(DMString* in);
typedef DMString* (__thiscall *DMStringNew)(DMString* this);
typedef void (__thiscall *DMStringFree)(DMString* this);

static GetServerMemUsage get_server_mem_usage = NULL;
static DMStringNew dm_string_new = NULL;
static DMStringFree dm_string_free = NULL;

// ??0DMString@@QAE@XZ
// ??1DMString@@QAE@XZ

DMString create_dmstring() {
	DMString ret = {0};
	dm_string_new(&ret);
	return ret;
}

static void free_dmstring(DMString* str) {
	dm_string_free(str);
}

static void cleanup_lib(HMODULE *byondcore)
{
	if (*byondcore != NULL)
		FreeLibrary(*byondcore);
}

__declspec(dllexport) __cdecl char *get_memory_stats(int argc, const char **argv)
{
	HMODULE byondcore __attribute__((cleanup(cleanup_lib))) = LoadLibrary("byondcore.dll");
	if(byondcore == NULL)
		return "error: failed to load byondcore";
	get_server_mem_usage = (GetServerMemUsage)GetProcAddress(byondcore, "?GetServerMemUsage@DungServer@@QAE?AUDMString@@XZ");
	if(get_server_mem_usage == NULL)
		return "error: failed to get address of DungServer::GetServerMemUsage";
	dm_string_new = (DMStringNew)GetProcAddress(byondcore, "??0DMString@@QAE@XZ");
	if(dm_string_new == NULL)
		return "error: failed to get address of DMString::DMString(void)";
	dm_string_free = (DMStringFree)GetProcAddress(byondcore, "??1DMString@@QAE@XZ");
	if(dm_string_free == NULL)
		return "error: failed to get address of DMString::~DMString()";
	DMString string __attribute__((cleanup(free_dmstring))) = create_dmstring();
	get_server_mem_usage(&string);
	return string.data->str;
}