OptimizedArray.sol

OptimizedArray.sol

pragma solidity ^0.4.24;

library OptimizedArray {
    struct Data {
        mapping(uint256 => uint256) m;
        uint256 length;
    }
    
    function length(Data storage data) internal view returns(uint256) {
        return data.length;
    }
    
    function setLength(Data storage data, uint256 newLength) internal returns(uint256) {
        data.length = newLength;
    }
    
    function push(Data storage data, uint256 value) internal returns(uint256) {
        data.m[data.length] = value;
        return data.length++;
    }
    
    function pop(Data storage data) internal returns(uint256 value) {
        value = data.m[--data.length];
        delete data.m[data.length];
    }
    
    function eraseDirty(Data storage data, uint start, uint len) internal {
        for (uint i = start; i < start + len; i++) {
            if (i >= data.length && data.m[i] > 0) {
                delete data.m[i];
            }
        }
    }
}

library DirtyArray {
    function setLength(uint[] storage arr, uint length) internal {
        assembly {
            sstore(arr_slot, length)
        }
    }
    
    function eraseDirty(uint[] storage arr, uint start, uint length) internal {
        for (uint i = start; i < start + length; i++) {
            if (i >= arr.length) {
                uint ptr;
                assembly {
                    ptr := add(keccak256(arr_slot, 0x20), i)
                    if gt(sload(ptr), 0) {
                        sstore(ptr, 0)
                    }
                }
            }
        }
    }
}

contract Test {
    using DirtyArray for *;
    uint[] public arr;
    
    function setLength(uint length) public {
        arr.setLength(length);
    }
    
    function eraseDirty(uint index, uint length) public {
        arr.eraseDirty(index, length);
    }
    
    function all() public view returns(uint[]) {
        return arr;
    }
    
    function arrLength() public view returns(uint) {
        return arr.length;
    }
    
    function func() public {
        while (gasleft() >= 50000) {
            arr.push(arr.length);
        }
    }
    
    function func2(uint len) public {
        arr.length = len;
    }
}