GameHackingBook-GameHackingCode/LuaScripts/Chapter5_VerifyMap.lua

function _verifyMap(address)
    local parentItem = readInteger(address + 4) or 0

    local parentLeftItem = readInteger(parentItem + 0) or 0
    local parentRightItem = readInteger(parentItem + 8) or 0

    local validParent =
        parentLeftItem == address
        or parentRightItem == address
    if (not validParent) then return false end

    local tries = 0
    local lastChecked = parentItem
    local parentsParent = readInteger(parentItem + 4) or 0
    while (readInteger(parentsParent + 4) ~= lastChecked and tries < 200) do
        tries = tries + 1
        lastChecked = parentsParent
        parentsParent = readInteger(parentsParent + 4) or 0
    end

    return readInteger(parentsParent + 4) == lastChecked
end


function isValueInMap(valueAddress)
    for address = valueAddress - 12, valueAddress - 52, -4 do
        if (_verifyMap(address)) then
            return address
        end
    end
    return 0
end

local node = isValueInMap(addressOfSomeValue)
if (node > 0) then
    print(string.format("Value in map, top of node at 0x0%x", node))
end