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

static int enable_large_pages(void)
{
	HANDLE token = INVALID_HANDLE_VALUE;
	TOKEN_PRIVILEGES priv = { 0 };
	int ret = 1;

	if (!(OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &token)))
		goto error;

	if (!(LookupPrivilegeValue(0, SE_LOCK_MEMORY_NAME, &priv.Privileges[0].Luid)))
		goto error;

	priv.PrivilegeCount = 1;
	priv.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;

	if (!(AdjustTokenPrivileges(token, FALSE, &priv, 0, 0, 0)))
		goto error;

	ret = 0;
error:
	CloseHandle(token);
	return ret;
}

static void print_last_error(const char *msg)
{
	const DWORD flags = FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS;
	const DWORD langid = MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT);
	char buf[256];

	FormatMessageA(flags, 0, GetLastError(), langid, buf, sizeof(buf), 0);
	fprintf(stderr, "%s: %s\n", msg, buf);
}

int main()
{
	const int num_tries = 1000000;

	HANDLE current_process = GetCurrentProcess();
	SIZE_T large_page_minimum = 0;
	LPVOID page = 0;
	int found = 0;
	int i, j;

	if (enable_large_pages()) {
		print_last_error("could not enable large pages");
		return 1;
	}

	large_page_minimum = GetLargePageMinimum();

	for (i = 0; i < num_tries; ++i) {
		const DWORD large_page_flags = MEM_COMMIT | MEM_RESERVE | MEM_LARGE_PAGES;
		char buffer[256];

		page = VirtualAllocEx(current_process, 0, large_page_minimum, large_page_flags, PAGE_READWRITE);
		if (!page) {
			print_last_error("could not allocate page");
			return 1;
		}

		memcpy(buffer, page, sizeof(buffer));
		for (j = 0; j < sizeof(buffer); ++j) {
			if (buffer[j]) {
				int refreshed;

				Sleep(1);
				refreshed = ((char *)page)[j];

				printf("stale data at offset %d: %d\n", j, buffer[j]);
				printf("1 ms later the data is: %d\n", refreshed);
				printf("iterations taken: %d\n", i);
				found = 1;
				break;
			}
		}
		if (found)
			break;

		memset(page, i % 256, sizeof(buffer));
		if (VirtualFreeEx(current_process, page, 0, MEM_RELEASE) == FALSE) {
			print_last_error("could not release page");
			return 1;
		}
	}

	if (!found)
		puts("bug not reproduced\n");

	if (page)
		VirtualFreeEx(current_process, page, 0, MEM_RELEASE);
	return 0;
}