Initialize a big fixed length array in Solidity

Question

I'm building a game on ethereum as my first project and I'm facing with the storage and gas limits. I would like to store a storage smart contract on the blockchain to be queried after the deployment. I really need to initialize a fixed length array with constant values I insert manually. My situation is the following:

    contract A {

...some states variables/modifiers and events......

uint[] public vector = new uint[](162);

vector = [.......1, 2, 3,......];

function A () {

....some code....

ContractB contract = new ContractB(vector);

}

....functions....

}

This code doesn't deploy. Apparently I exceed gas limits on remix. I tried the following:

• I split the vector in 10 different vectors and then pass just one of them to the constructor. With this the deploy works.

I really need to have just one single vector because it represents the edges set of a graph where ContractB is the data structure to build a graph. Vectors elements are ordered like this:

vector = [edge1From, edge1To, edge2From, edge2To,.......]

and I got 81 edges (162 entries in the vector).

I tought I can create a setData function that push the values in the vector one by one calling this function after the deployment but this is not my case because I need to have the vector filled before the call

ContractB contract = new ContractB(vector);

Now I can see I have two doubts:

1) Am I wrong trying to pass a vector as parameter in a function call inside the A constructor ?

2) I can see that I can create a double mapping for the edges. Something like

mapping (bool => mapping(uint => uint)) 

but then I will need multi-key valued mappings (more edges starting from the same point) and I will have the problem to initialize all the mappings at once like I do with the vector?

Answer 1

Why does the contract need to be initialized at construction time?

This should work

pragma solidity ^0.4.2;

contract Graph {
    address owner;

    struct GraphEdge {
        uint128 from;
        uint128 to;
    }

    GraphEdge[] public graph;
    bool public initialized = false;

    constructor() public {
        owner = msg.sender;
    }

    function addEdge(uint128 edgeFrom, uint128 edgeTo) public {
        require(!initialized);
        graph.push(GraphEdge({
            from: edgeFrom,
            to: edgeTo
        }));
    }

    function finalize() public {
        require(msg.sender == owner);
        initialized = true;
    }
}

contract ContractB {
    Graph graph;

    constructor(address graphAddress) public {
        Graph _graph = Graph(graphAddress);
        require(_graph.initialized());
        graph = _graph;
    }
}