mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
76 lines
2.0 KiB
Solidity
76 lines
2.0 KiB
Solidity
pragma solidity ^0.4.11;
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/**
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* @title DayLimit
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* @dev Base contract that enables methods to be protected by placing a linear limit (specifiable)
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* on a particular resource per calendar day. Is multiowned to allow the limit to be altered.
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*/
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contract DayLimit {
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uint256 public dailyLimit;
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uint256 public spentToday;
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uint256 public lastDay;
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/**
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* @dev Constructor that sets the passed value as a dailyLimit.
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* @param _limit uint256 to represent the daily limit.
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*/
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function DayLimit(uint256 _limit) {
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dailyLimit = _limit;
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lastDay = today();
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}
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/**
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* @dev sets the daily limit. Does not alter the amount already spent today.
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* @param _newLimit uint256 to represent the new limit.
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*/
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function _setDailyLimit(uint256 _newLimit) internal {
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dailyLimit = _newLimit;
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}
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/**
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* @dev Resets the amount already spent today.
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*/
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function _resetSpentToday() internal {
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spentToday = 0;
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}
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/**
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* @dev Checks to see if there is enough resource to spend today. If true, the resource may be expended.
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* @param _value uint256 representing the amount of resource to spend.
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* @return A boolean that is True if the resource was spended and false otherwise.
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*/
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function underLimit(uint256 _value) internal returns (bool) {
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// reset the spend limit if we're on a different day to last time.
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if (today() > lastDay) {
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spentToday = 0;
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lastDay = today();
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}
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// check to see if there's enough left - if so, subtract and return true.
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// overflow protection // dailyLimit check
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if (spentToday + _value >= spentToday && spentToday + _value <= dailyLimit) {
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spentToday += _value;
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return true;
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}
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return false;
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}
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/**
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* @dev Private function to determine today's index
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* @return uint256 of today's index.
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*/
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function today() private constant returns (uint256) {
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return now / 1 days;
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}
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/**
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* @dev Simple modifier for daily limit.
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*/
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modifier limitedDaily(uint256 _value) {
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if (!underLimit(_value)) {
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throw;
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}
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_;
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}
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}
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