问如何压缩数据以获得最便宜的存储读取？

EN

contract CompressedData {

uint256 constant pow2_16 = 2 ** 16;
uint256 constant pow2_112 = 2 ** 112;
uint256 constant full112 = 2 ** 112 - 1;
uint256 constant full16 = 2 ** 16 - 1;

struct CompData {
    int16 x1;
    int112 y1;
    int16 x2;
    int112 y2;
}

mapping(uint => CompData) data;
mapping(uint => bytes32) decData;

constructor() public {
    data[0].x1 = 1;
    data[0].y1 = -1000;
    data[0].x2 = 2;
    data[0].y2 = -2000;

    decData[0] = encodeData(11, -10, 21, -20);

    decData[1] = encodeStepFunctionData(13, -13, 15, -15);
}


   
function getData (uint256 x) external view returns (int256, int256, int256, int256) {
    // gas result according to remix: 1306
        CompData storage pData = data[x];
        return(pData.x1, pData.y1, pData.x2, pData.y2);   
    }
 


function getDataMem (uint256 x) external view returns (int256, int256, int256, int256) {
    // gas result according to remix: 1681
    CompData memory _data = data[x];
    return(_data.x1, _data.y1, _data.x2, _data.y2);   
}
    
function encodeData(int256 x1, int256 x2, int256 x3, int256 x4) public pure returns(bytes32 result) {
    uint256 val;
    val = uint256(x1) & full16;
    val |= (uint256(x2) & full112) * pow2_16;
    val |= (uint256(x3) & full16) * pow2_16 * pow2_112;
    val |= (uint256(x4) & full112) * pow2_16 * pow2_112 * pow2_16;
    
    return(bytes32(val));
}

function getDecData(uint256 x) external view returns (int256 x1, int256 y1, int256 x2, int256 y2) {
// gas result according to remix: 1298
    uint256 val = uint256(decData[x]);
    x1 = int256(int16(val));
    y1 = int256(int112((val / pow2_16)));
    x2 = int256(int16(val / (pow2_16 * pow2_112)));
    y2 = int256(int112((val / (pow2_16 * pow2_112 * pow2_16))));
}

function getShiftDecData(uint256 x) external view returns (int256 x1, int256 y1, int256 x2, int256 y2) {
// gas result according to remix: 1258
    
    uint256 val = uint256(decData[x]);
    x1 = int256(int16(val));
    y1 = int256(int112((val >> 16)));
    x2 = int256(int16(val >> (16 + 112)));
    y2 = int256(int112((val >> (16 + 112 + 16))));
}

function getDecodedAsm() external view returns (uint112 x1, int16 y1, uint112 x2, int16 y2){
// gas result according to remix: 1346
    bytes memory tmp = abi.encodePacked(decData[1]); //assembly decoded data in slot 1
    assembly {
        x1 := mload(add(tmp, 14))
        y1 := mload(add(tmp, 16))
        x2 := mload(add(tmp, 30))
        y2 := mload(add(tmp, 32))
    }
}

function encodeStepFunctionData(uint112 x1, int16 y1, uint112 x2, int16 y2) public pure returns(bytes32 out) {
    bytes memory _data = abi.encodePacked(x1, y1, x2, y2);
    assembly {
        // skip 1 slot for data.length
        out := mload(add(_data, 32))
    }
}