Check bytes32 exists in bytes32[]

Question

I would like to know if this is possible to check in a simple way if a bytes32 value exists in an array of bytes32 value please?

contract Test {
    struct TestStruct {
        string name;
        bytes32 value;
    }

    struct ConfigStruct {
        bytes32[] valuesPossible;
    }

    TestStruct[] public structs;
    ConfigStruct[] configs;


    function constructor(bytes32[] _valuesToStore) public {
        configs.push(ConfigStruct(_valuesToStore));
    }

    function add(string _name, uint _idConfig, bytes32 _valueToStore) valueIsPossible(_idConfig, _valueToStore) public {
        structs.push(TestStruct("test", _valueToStore));
    }

    modifier valueIsPossible(uint _idConfig, bytes32 _valueToStore) {
        //require(configs[_idConfig].valuesPossible[_valueToStore]); // How to check that
        _;
    }
}

Thanks by advance

EDIT: Sorry my code was not very accurate, I updated it

Answer 1

Simplest way : iterate over the array.

But it may not be the cheapest solution, since you have to iterate potentially the entire array to find the value you are looking for.

Depending on what you want to do, you could use a mapping instead, and find if it's "present" in O(1).

An example would be :

mapping (bytes32 => bool) public ValueExists;

Now, if you really need your array, you can combine the mapping solution and your array.