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@yuyasugano
Created January 11, 2019 03:30
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Cow breeding smart contract
pragma solidity ^0.4.23;
import "./ownable.sol";
import "openzeppelin-solidity/contracts/token/ERC721/ERC721.sol";
/**
* @title CowBreeding
* @dev Cow Basic Implementation to breed them and provides basic functions.
*/
contract CowBreeding is Ownable {
using SafeMath for uint256;
event CowBirth(uint cowNumber, uint momNumber, string cowType, string cowSex);
uint cowDigits = 10;
uint cowModulus = 10 ** cowDigits;
struct Cow {
uint cowNum;
uint cowMom;
uint birthDate;
string types;
string sex;
}
Cow[] public cows;
// Mapping from cow ID to owner
mapping (uint => address) public cowToOwner;
// Mapping from owner to number of owned cow
mapping (address => uint) ownerCowCount;
// Mapping from token ID to number of cows
mapping (uint => uint) idToCowNum;
// Mapping from number of cows to token ID
mapping (uint => uint) cowNumToId;
modifier onlyOwnerOf(address _ownerOf) {
require(msg.sender == _ownerOf);
_;
}
/**
* @dev Internal function to give birth of a cow with variables
* @param _cowNum new cow identity number
* @param _cowMom new cow's mother identity number
* @param _types new cow's type such as BrownSwiss
* @param _sex new cow's sex male or female
*/
function _cowBirth(uint _cowNum, uint _cowMom, string _types, string _sex) internal {
uint id = cows.push(Cow(_cowNum, _cowMom, block.timestamp, _types, _sex)) - 1;
idToCowNum[id] = _cowNum;
cowNumToId[_cowNum] = id;
cowToOwner[_cowNum] = msg.sender;
ownerCowCount[msg.sender] = ownerCowCount[msg.sender].add(1);
emit CowBirth(_cowNum, _cowMom, _types, _sex);
}
/**
* @dev Gives birth of a cow with variables
* @param _cowMom new cow's mother identity number
* @param _types new cow's type such as BrownSwiss
* @param _sex new cow's sex male or female
*/
function cowBirth(uint _cowMom, string _types, string _sex) public {
// Generate a unique identifier for cows
uint _cowNum = uint(keccak256(abi.encodePacked(msg.sender, blockhash(block.number - 1)))) % cowModulus;
_cowBirth(_cowNum, _cowMom, _types, _sex);
}
/**
* @dev Gets cows in struct from the owner address
* @param _owner cow owner address
* @return uint array of cow structs
*/
function getCowsByOwner(address _owner) external view returns (uint[]) {
uint[] memory cowsByOwner = new uint[](ownerCowCount[_owner]);
uint counter = 0;
uint number;
for (uint i = 0; i < cows.length; i++) {
number = idToCowNum[i];
if (cowToOwner[number] == _owner) {
cowsByOwner[counter] = number;
counter = counter.add(1);
}
}
return cowsByOwner;
}
/**
* @dev Gets cow counts from the owner address
* @param _owner cow owner address
* @return uint of cow counts of the owner
*/
function getCountByOwner(address _owner) external view returns (uint) {
return ownerCowCount[_owner];
}
/**
* @dev Gets number of cows from the cow id
* @param _cowNum cow identity number
* @return uint of cow id
*/
function getIdByCowNum(uint _cowNum) external view returns (uint) {
return cowNumToId[_cowNum];
}
/**
* @dev Gets an owner address from a cow identity number
* @param _cowNum cow identity number
* @return address of the owner of the mentioned identity number
*/
function getOwnerByCow(uint _cowNum) public view returns (address) {
return cowToOwner[_cowNum];
}
}
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