gastoken_free.sol

free.sol

function freeStorage(uint256 value) internal {
    uint256 storage_location_array = STORAGE_LOCATION_ARRAY;  // can't use constants inside assembly
    // Read supply
    uint256 supply;
    assembly {
        supply := sload(storage_location_array)
    }
    // Clear memory locations in interval [l, r]
    uint256 l = storage_location_array + supply - value + 1;
    uint256 r = storage_location_array + supply;
    for (uint256 i = l; i <= r; i++) {
        assembly {
            sstore(i, 0)
        }
    }
    // Write updated supply
    assembly {
        sstore(storage_location_array, sub(supply, value))
    }
}