topic-grouped lists of addresses with linked id contracts

gistfile1.txt

// convenience nameserver
// name -> address
// address -> name

// [name, newOwnerAddress (optional)]
// only one name allowed per address
// newOwnerAddress will only be applicable if the name is already claimed

// if the name is invalid, stop
if tx.data[0] < 100:
    stop
// if the name has already been claimed
if contract.storage[tx.data[0]]:
    // if the sender isn't the current owner, stop
    if contract.storage[tx.data[0]] != tx.sender:
        stop
    // if the newOwnerAddress is invalid, stop
    if tx.data[1] < 100:
        stop
    // set new owner
    contract.storage[tx.sender] = 0
    contract.storage[tx.data[0]] = tx.data[1]
// the name has not been claimed
else:
    //if the sending address already has a name, stop
    if contract.storage[tx.sender]:
        stop
    // set name owner as sending address
    contract.storage[tx.sender] = tx.data[0]
    contract.storage[tx.data[0]] = tx.sender


// Topic list -> [addresses], address -> contract 
// two commands: update contract address, update topic
// enforces:
//  - one topic per address
//  - one contract per address

// [0,contractAddress] - updates sender's contract address (0 for delete)
// [1, topic] - updates sender's topic

// update contract
if tx.data[0] == 0:
    if tx.data[1] < 1000: // if the contractAddress isn't valid, stop
        stop
    contract.storage[tx.sender] = tx.data[1]
// update topic
if tx.data[0] == 1:
    if tx.data[1] < 1000: // if the topic isn't valid, stop
        stop
    // if this address had an old topic, decrement that list
    if contract.storage[tx.sender + 1]:
        TOPICROOT = sha3(32,contract.storage[tx.sender+1]) 
        LEN = contract.storage[TOPICROOT]
        INDEX = contract.storage[tx.sender + 2]
        // set swapped address to new index position and set address index
        contract.storage[TOPICROOT+INDEX] = contract.storage[TOPICROOT+LEN]
        contract.storage[contract.storage[TOPICROOT+INDEX] + 2] = INDEX
        contract.storage[LEN] = 0
        // decrement old topic length
        contract.storage[sha3(32,contract.storage[tx.sender + 1])] = LEN - 1
    TOPICROOT = sha3(32,tx.data[1])
    LEN = contract.storage[TOPICROOT]
    // add address to topic list and increment length
    contract.storage[TOPICROOT+LEN+1] = tx.sender
    contract.storage[TOPICROOT] = LEN + 1
    // store topic and index in list for later lookup
    contract.storage[tx.sender+1] = tx.data[1]
    contract.storage[tx.sender+2] = LEN + 1