Get limit of the set of pages allocated at the same base

snippet.cpp

LPVOID get_area_limit(HANDLE processHandle, LPVOID first_addr)
{
	MEMORY_BASIC_INFORMATION page_info = { 0 };
	//go to the beginning of the area:
	SIZE_T out = VirtualQueryEx(processHandle, first_addr, &page_info, sizeof(page_info));
	if (GetLastError() == ERROR_INVALID_PARAMETER) {
		return nullptr;
	}
	LPVOID alloc_base = page_info.AllocationBase;
	LPVOID next_area = page_info.BaseAddress;
	do {
		memset(&page_info, 0, sizeof(MEMORY_BASIC_INFORMATION));
		SIZE_T out = VirtualQueryEx(processHandle, next_area, &page_info, sizeof(page_info));
		if (out != sizeof(page_info)) {
			if (GetLastError() == ERROR_INVALID_PARAMETER) {
				break;
			}
			break;
		}
		if (!alloc_base) { //set first
			alloc_base = page_info.AllocationBase;
		}
		if (page_info.AllocationBase != alloc_base) break; //not the same allocation base
		if ((page_info.State & MEM_FREE) || (page_info.State & MEM_COMMIT) == 0) {
			break; //not commited
		}
		next_area = LPVOID((ULONG_PTR)page_info.BaseAddress + page_info.RegionSize);
	} while (true);

	if (!alloc_base) {
		return nullptr; //could not find ANY allocated area at this address
	}
	if ((ULONG_PTR)next_area < (ULONG_PTR)first_addr) {
		return nullptr;
	}
	return next_area;
}