Contract Source Code:
File 1 of 1 : Trophy
pragma solidity ^0.4.13;
library AddressUtils {
/**
* Returns whether the target address is a contract
* @dev This function will return false if invoked during the constructor of a contract,
* as the code is not actually created until after the constructor finishes.
* @param _addr address to check
* @return whether the target address is a contract
*/
function isContract(address _addr) internal view returns (bool) {
uint256 size;
// XXX Currently there is no better way to check if there is a contract in an address
// than to check the size of the code at that address.
// See https://ethereum.stackexchange.com/a/14016/36603
// for more details about how this works.
// TODO Check this again before the Serenity release, because all addresses will be
// contracts then.
// solium-disable-next-line security/no-inline-assembly
assembly { size := extcodesize(_addr) }
return size > 0;
}
}
interface ERC165 {
/**
* @notice Query if a contract implements an interface
* @param _interfaceId The interface identifier, as specified in ERC-165
* @dev Interface identification is specified in ERC-165. This function
* uses less than 30,000 gas.
*/
function supportsInterface(bytes4 _interfaceId)
external
view
returns (bool);
}
contract SupportsInterfaceWithLookup is ERC165 {
bytes4 public constant InterfaceId_ERC165 = 0x01ffc9a7;
/**
* 0x01ffc9a7 ===
* bytes4(keccak256('supportsInterface(bytes4)'))
*/
/**
* @dev a mapping of interface id to whether or not it's supported
*/
mapping(bytes4 => bool) internal supportedInterfaces;
/**
* @dev A contract implementing SupportsInterfaceWithLookup
* implement ERC165 itself
*/
constructor()
public
{
_registerInterface(InterfaceId_ERC165);
}
/**
* @dev implement supportsInterface(bytes4) using a lookup table
*/
function supportsInterface(bytes4 _interfaceId)
external
view
returns (bool)
{
return supportedInterfaces[_interfaceId];
}
/**
* @dev private method for registering an interface
*/
function _registerInterface(bytes4 _interfaceId)
internal
{
require(_interfaceId != 0xffffffff);
supportedInterfaces[_interfaceId] = true;
}
}
library SafeMath {
/**
* @dev Multiplies two numbers, throws on overflow.
*/
function mul(uint256 _a, uint256 _b) internal pure returns (uint256 c) {
// Gas optimization: this is cheaper than asserting 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
if (_a == 0) {
return 0;
}
c = _a * _b;
assert(c / _a == _b);
return c;
}
/**
* @dev Integer division of two numbers, truncating the quotient.
*/
function div(uint256 _a, uint256 _b) internal pure returns (uint256) {
// assert(_b > 0); // Solidity automatically throws when dividing by 0
// uint256 c = _a / _b;
// assert(_a == _b * c + _a % _b); // There is no case in which this doesn't hold
return _a / _b;
}
/**
* @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
*/
function sub(uint256 _a, uint256 _b) internal pure returns (uint256) {
assert(_b <= _a);
return _a - _b;
}
/**
* @dev Adds two numbers, throws on overflow.
*/
function add(uint256 _a, uint256 _b) internal pure returns (uint256 c) {
c = _a + _b;
assert(c >= _a);
return c;
}
}
contract ERC721Basic is ERC165 {
bytes4 internal constant InterfaceId_ERC721 = 0x80ac58cd;
/*
* 0x80ac58cd ===
* bytes4(keccak256('balanceOf(address)')) ^
* bytes4(keccak256('ownerOf(uint256)')) ^
* bytes4(keccak256('approve(address,uint256)')) ^
* bytes4(keccak256('getApproved(uint256)')) ^
* bytes4(keccak256('setApprovalForAll(address,bool)')) ^
* bytes4(keccak256('isApprovedForAll(address,address)')) ^
* bytes4(keccak256('transferFrom(address,address,uint256)')) ^
* bytes4(keccak256('safeTransferFrom(address,address,uint256)')) ^
* bytes4(keccak256('safeTransferFrom(address,address,uint256,bytes)'))
*/
bytes4 internal constant InterfaceId_ERC721Exists = 0x4f558e79;
/*
* 0x4f558e79 ===
* bytes4(keccak256('exists(uint256)'))
*/
bytes4 internal constant InterfaceId_ERC721Enumerable = 0x780e9d63;
/**
* 0x780e9d63 ===
* bytes4(keccak256('totalSupply()')) ^
* bytes4(keccak256('tokenOfOwnerByIndex(address,uint256)')) ^
* bytes4(keccak256('tokenByIndex(uint256)'))
*/
bytes4 internal constant InterfaceId_ERC721Metadata = 0x5b5e139f;
/**
* 0x5b5e139f ===
* bytes4(keccak256('name()')) ^
* bytes4(keccak256('symbol()')) ^
* bytes4(keccak256('tokenURI(uint256)'))
*/
event Transfer(
address indexed _from,
address indexed _to,
uint256 indexed _tokenId
);
event Approval(
address indexed _owner,
address indexed _approved,
uint256 indexed _tokenId
);
event ApprovalForAll(
address indexed _owner,
address indexed _operator,
bool _approved
);
function balanceOf(address _owner) public view returns (uint256 _balance);
function ownerOf(uint256 _tokenId) public view returns (address _owner);
function exists(uint256 _tokenId) public view returns (bool _exists);
function approve(address _to, uint256 _tokenId) public;
function getApproved(uint256 _tokenId)
public view returns (address _operator);
function setApprovalForAll(address _operator, bool _approved) public;
function isApprovedForAll(address _owner, address _operator)
public view returns (bool);
function transferFrom(address _from, address _to, uint256 _tokenId) public;
function safeTransferFrom(address _from, address _to, uint256 _tokenId)
public;
function safeTransferFrom(
address _from,
address _to,
uint256 _tokenId,
bytes _data
)
public;
}
contract ERC721Enumerable is ERC721Basic {
function totalSupply() public view returns (uint256);
function tokenOfOwnerByIndex(
address _owner,
uint256 _index
)
public
view
returns (uint256 _tokenId);
function tokenByIndex(uint256 _index) public view returns (uint256);
}
contract ERC721Metadata is ERC721Basic {
function name() external view returns (string _name);
function symbol() external view returns (string _symbol);
function tokenURI(uint256 _tokenId) public view returns (string);
}
contract ERC721 is ERC721Basic, ERC721Enumerable, ERC721Metadata {
}
contract ERC721BasicToken is SupportsInterfaceWithLookup, ERC721Basic {
using SafeMath for uint256;
using AddressUtils for address;
// Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
// which can be also obtained as `ERC721Receiver(0).onERC721Received.selector`
bytes4 private constant ERC721_RECEIVED = 0x150b7a02;
// Mapping from token ID to owner
mapping (uint256 => address) internal tokenOwner;
// Mapping from token ID to approved address
mapping (uint256 => address) internal tokenApprovals;
// Mapping from owner to number of owned token
mapping (address => uint256) internal ownedTokensCount;
// Mapping from owner to operator approvals
mapping (address => mapping (address => bool)) internal operatorApprovals;
constructor()
public
{
// register the supported interfaces to conform to ERC721 via ERC165
_registerInterface(InterfaceId_ERC721);
_registerInterface(InterfaceId_ERC721Exists);
}
/**
* @dev Gets the balance of the specified address
* @param _owner address to query the balance of
* @return uint256 representing the amount owned by the passed address
*/
function balanceOf(address _owner) public view returns (uint256) {
require(_owner != address(0));
return ownedTokensCount[_owner];
}
/**
* @dev Gets the owner of the specified token ID
* @param _tokenId uint256 ID of the token to query the owner of
* @return owner address currently marked as the owner of the given token ID
*/
function ownerOf(uint256 _tokenId) public view returns (address) {
address owner = tokenOwner[_tokenId];
require(owner != address(0));
return owner;
}
/**
* @dev Returns whether the specified token exists
* @param _tokenId uint256 ID of the token to query the existence of
* @return whether the token exists
*/
function exists(uint256 _tokenId) public view returns (bool) {
address owner = tokenOwner[_tokenId];
return owner != address(0);
}
/**
* @dev Approves another address to transfer the given token ID
* The zero address indicates there is no approved address.
* There can only be one approved address per token at a given time.
* Can only be called by the token owner or an approved operator.
* @param _to address to be approved for the given token ID
* @param _tokenId uint256 ID of the token to be approved
*/
function approve(address _to, uint256 _tokenId) public {
address owner = ownerOf(_tokenId);
require(_to != owner);
require(msg.sender == owner || isApprovedForAll(owner, msg.sender));
tokenApprovals[_tokenId] = _to;
emit Approval(owner, _to, _tokenId);
}
/**
* @dev Gets the approved address for a token ID, or zero if no address set
* @param _tokenId uint256 ID of the token to query the approval of
* @return address currently approved for the given token ID
*/
function getApproved(uint256 _tokenId) public view returns (address) {
return tokenApprovals[_tokenId];
}
/**
* @dev Sets or unsets the approval of a given operator
* An operator is allowed to transfer all tokens of the sender on their behalf
* @param _to operator address to set the approval
* @param _approved representing the status of the approval to be set
*/
function setApprovalForAll(address _to, bool _approved) public {
require(_to != msg.sender);
operatorApprovals[msg.sender][_to] = _approved;
emit ApprovalForAll(msg.sender, _to, _approved);
}
/**
* @dev Tells whether an operator is approved by a given owner
* @param _owner owner address which you want to query the approval of
* @param _operator operator address which you want to query the approval of
* @return bool whether the given operator is approved by the given owner
*/
function isApprovedForAll(
address _owner,
address _operator
)
public
view
returns (bool)
{
return operatorApprovals[_owner][_operator];
}
/**
* @dev Transfers the ownership of a given token ID to another address
* Usage of this method is discouraged, use `safeTransferFrom` whenever possible
* Requires the msg sender to be the owner, approved, or operator
* @param _from current owner of the token
* @param _to address to receive the ownership of the given token ID
* @param _tokenId uint256 ID of the token to be transferred
*/
function transferFrom(
address _from,
address _to,
uint256 _tokenId
)
public
{
require(isApprovedOrOwner(msg.sender, _tokenId));
require(_from != address(0));
require(_to != address(0));
clearApproval(_from, _tokenId);
removeTokenFrom(_from, _tokenId);
addTokenTo(_to, _tokenId);
emit Transfer(_from, _to, _tokenId);
}
/**
* @dev Safely transfers the ownership of a given token ID to another address
* If the target address is a contract, it must implement `onERC721Received`,
* which is called upon a safe transfer, and return the magic value
* `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`; otherwise,
* the transfer is reverted.
*
* Requires the msg sender to be the owner, approved, or operator
* @param _from current owner of the token
* @param _to address to receive the ownership of the given token ID
* @param _tokenId uint256 ID of the token to be transferred
*/
function safeTransferFrom(
address _from,
address _to,
uint256 _tokenId
)
public
{
// solium-disable-next-line arg-overflow
safeTransferFrom(_from, _to, _tokenId, "");
}
/**
* @dev Safely transfers the ownership of a given token ID to another address
* If the target address is a contract, it must implement `onERC721Received`,
* which is called upon a safe transfer, and return the magic value
* `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`; otherwise,
* the transfer is reverted.
* Requires the msg sender to be the owner, approved, or operator
* @param _from current owner of the token
* @param _to address to receive the ownership of the given token ID
* @param _tokenId uint256 ID of the token to be transferred
* @param _data bytes data to send along with a safe transfer check
*/
function safeTransferFrom(
address _from,
address _to,
uint256 _tokenId,
bytes _data
)
public
{
transferFrom(_from, _to, _tokenId);
// solium-disable-next-line arg-overflow
require(checkAndCallSafeTransfer(_from, _to, _tokenId, _data));
}
/**
* @dev Returns whether the given spender can transfer a given token ID
* @param _spender address of the spender to query
* @param _tokenId uint256 ID of the token to be transferred
* @return bool whether the msg.sender is approved for the given token ID,
* is an operator of the owner, or is the owner of the token
*/
function isApprovedOrOwner(
address _spender,
uint256 _tokenId
)
internal
view
returns (bool)
{
address owner = ownerOf(_tokenId);
// Disable solium check because of
// https://github.com/duaraghav8/Solium/issues/175
// solium-disable-next-line operator-whitespace
return (
_spender == owner ||
getApproved(_tokenId) == _spender ||
isApprovedForAll(owner, _spender)
);
}
/**
* @dev Internal function to mint a new token
* Reverts if the given token ID already exists
* @param _to The address that will own the minted token
* @param _tokenId uint256 ID of the token to be minted by the msg.sender
*/
function _mint(address _to, uint256 _tokenId) internal {
require(_to != address(0));
addTokenTo(_to, _tokenId);
emit Transfer(address(0), _to, _tokenId);
}
/**
* @dev Internal function to burn a specific token
* Reverts if the token does not exist
* @param _tokenId uint256 ID of the token being burned by the msg.sender
*/
function _burn(address _owner, uint256 _tokenId) internal {
clearApproval(_owner, _tokenId);
removeTokenFrom(_owner, _tokenId);
emit Transfer(_owner, address(0), _tokenId);
}
/**
* @dev Internal function to clear current approval of a given token ID
* Reverts if the given address is not indeed the owner of the token
* @param _owner owner of the token
* @param _tokenId uint256 ID of the token to be transferred
*/
function clearApproval(address _owner, uint256 _tokenId) internal {
require(ownerOf(_tokenId) == _owner);
if (tokenApprovals[_tokenId] != address(0)) {
tokenApprovals[_tokenId] = address(0);
}
}
/**
* @dev Internal function to add a token ID to the list of a given address
* @param _to address representing the new owner of the given token ID
* @param _tokenId uint256 ID of the token to be added to the tokens list of the given address
*/
function addTokenTo(address _to, uint256 _tokenId) internal {
require(tokenOwner[_tokenId] == address(0));
tokenOwner[_tokenId] = _to;
ownedTokensCount[_to] = ownedTokensCount[_to].add(1);
}
/**
* @dev Internal function to remove a token ID from the list of a given address
* @param _from address representing the previous owner of the given token ID
* @param _tokenId uint256 ID of the token to be removed from the tokens list of the given address
*/
function removeTokenFrom(address _from, uint256 _tokenId) internal {
require(ownerOf(_tokenId) == _from);
ownedTokensCount[_from] = ownedTokensCount[_from].sub(1);
tokenOwner[_tokenId] = address(0);
}
/**
* @dev Internal function to invoke `onERC721Received` on a target address
* The call is not executed if the target address is not a contract
* @param _from address representing the previous owner of the given token ID
* @param _to target address that will receive the tokens
* @param _tokenId uint256 ID of the token to be transferred
* @param _data bytes optional data to send along with the call
* @return whether the call correctly returned the expected magic value
*/
function checkAndCallSafeTransfer(
address _from,
address _to,
uint256 _tokenId,
bytes _data
)
internal
returns (bool)
{
if (!_to.isContract()) {
return true;
}
bytes4 retval = ERC721Receiver(_to).onERC721Received(
msg.sender, _from, _tokenId, _data);
return (retval == ERC721_RECEIVED);
}
}
contract Trophy is SupportsInterfaceWithLookup, ERC721BasicToken, ERC721 {
// Use solidity-stringutils
using strings for *;
// Token name
string internal name_;
// Token symbol
string internal symbol_;
// Mapping from owner to list of owned token IDs
mapping(address => uint256[]) public ownedTokens;
// Mapping from token ID to index of the owner tokens list
mapping(uint256 => uint256) public ownedTokensIndex;
// Array with all token ids, used for enumeration
uint256[] public allTokens;
// Mapping from token id to position in the allTokens array
mapping(uint256 => uint256) public allTokensIndex;
// Super administrator for this contract
address public manager;
// Next token identifier
uint256 public nextTokenId = 1;
// Next token type
uint256 public nextTokenType = 1;
// URI prefix for all token URIs
string public tokenURIPrefix;
// Types associated with tokens
mapping (uint256 => uint256) public tokenTypes;
// Owners of types
mapping (uint256 => address) public tokenTypeIssuers;
// A mapping of token id to issuer
mapping (uint256 => address) public tokenIssuer;
// A map of tokens by a type
mapping (uint256 => uint256[]) public tokensByType;
// Event emitted upon token type creation
event TokenTypeCreated(
address _issuer,
uint256 _type,
uint256 _timestamp
);
// Event emmited upon token is issued
event TokenIssued(
address _issuer,
address _owner,
uint256 _type,
uint256 _tokenId,
uint256 _timestamp
);
// Event emmited upon token is revoked
event TokenRevoked(
address _issuer,
address _owner,
uint256 _type,
uint256 _tokenId,
uint256 _timestamp
);
// Event emmited upon token issuance is transferred
event IssuanceTransferred(
uint256 _type,
address _oldIssuer,
address _newIssuer,
uint256 _timestamp
);
// Event emmited upon transfer all tokens
event TransferAll(
address _oldAddress,
address _newAddress,
uint256 _timestamp
);
/**
* @dev Constructor function
*/
constructor(string _name, string _symbol, string _tokenURIPrefix) public {
name_ = _name;
symbol_ = _symbol;
manager = msg.sender;
tokenURIPrefix = _tokenURIPrefix;
// register the supported interfaces to conform to ERC721 via ERC165
_registerInterface(InterfaceId_ERC721Enumerable);
_registerInterface(InterfaceId_ERC721Metadata);
}
/**
* @dev Gets the token name
* @return string representing the token name
*/
function name() external view returns (string) {
return name_;
}
/**
* @dev Gets the token symbol
* @return string representing the token symbol
*/
function symbol() external view returns (string) {
return symbol_;
}
/**
* @dev Returns an URI for a given token ID
* Throws if the token ID does not exist. May return an empty string.
* @param _tokenId uint256 ID of the token to query
*/
function tokenURI(uint256 _tokenId) public view returns (string) {
require(tokenOwner[_tokenId] != address(0));
return tokenURIPrefix.toSlice().concat(uint2str(_tokenId).toSlice());
}
/**
* @dev Gets the token ID at a given index of the tokens list of the requested owner
* @param _owner address owning the tokens list to be accessed
* @param _index uint256 representing the index to be accessed of the requested tokens list
* @return uint256 token ID at the given index of the tokens list owned by the requested address
*/
function tokenOfOwnerByIndex(
address _owner,
uint256 _index
)
public
view
returns (uint256)
{
require(_index < balanceOf(_owner));
return ownedTokens[_owner][_index];
}
/**
* @dev Gets the total amount of tokens stored by the contract
* @return uint256 representing the total amount of tokens
*/
function totalSupply() public view returns (uint256) {
return allTokens.length;
}
/**
* @dev Gets the token ID at a given index of all the tokens in this contract
* Reverts if the index is greater or equal to the total number of tokens
* @param _index uint256 representing the index to be accessed of the tokens list
* @return uint256 token ID at the given index of the tokens list
*/
function tokenByIndex(uint256 _index) public view returns (uint256) {
require(_index < totalSupply());
return allTokens[_index];
}
/**
* @dev Implements ERC 721
*/
function implementsERC721() public pure returns (bool) {
return true;
}
/**
* @dev Creates a new token type
* @param _issuer address of the new token type issuer
*/
function createType(address _issuer) external {
require(
msg.sender == manager || msg.sender == _issuer,
"Only managers can issue trophies on behalf of others."
);
tokenTypeIssuers[nextTokenType] = _issuer;
emit TokenTypeCreated(_issuer, nextTokenType, block.timestamp); // solium-disable-line security/no-block-members
nextTokenType++;
}
/**
* @dev Issues a new token
* @param _issuer address of the new token type issuer
*/
function issue(address _issuer, address _owner, uint256 _type) public {
require(
(msg.sender == manager && tokenTypeIssuers[_type] != 0) || (msg.sender == _issuer && tokenTypeIssuers[_type] == _issuer), // solium-disable-line indentation
"Only managers and issuers can issue trophies."
);
_mint(_owner, nextTokenId);
tokenTypes[nextTokenId] = _type;
tokensByType[_type].push(nextTokenId);
emit TokenIssued(
_issuer,
_owner,
_type,
nextTokenId,
block.timestamp // solium-disable-line security/no-block-members
);
nextTokenId++;
}
/**
* @dev issues the same token to many addresses
* @param _issuer address of the new token type issuer
* @param _owners an array of addresses of token holders
* @param _type type of an token
*/
function issueBatch(address _issuer, address[] _owners, uint256 _type) external {
require(_owners.length > 0, "Owners cannot be empty");
for (uint256 index = 0; index < _owners.length; index++ ) {
issue(_issuer, _owners[index], _type);
}
}
/**
* @dev Revokes issuance permissions to another address
*/
function revoke(uint256 _tokenId) external {
address owner = tokenOwner[_tokenId];
uint256 tokenType = tokenTypes[_tokenId];
address issuer = tokenTypeIssuers[tokenType];
require(
msg.sender == manager || msg.sender == issuer || msg.sender == owner,
"Only managers, owners, and issuers of the trophy can revoke them."
);
_burn(owner, _tokenId);
uint256 tokenIndex;
bool tokenFound;
for (uint256 i = 0; i < tokensByType[tokenType].length; i++) {
if (tokensByType[tokenType][i] == _tokenId) {
tokenIndex = i;
tokenFound = true;
break;
}
}
require(tokenFound, "token not found");
uint256 lastTokenIndex = tokensByType[tokenType].length.sub(1);
uint256 lastToken = tokensByType[tokenType][lastTokenIndex];
tokensByType[tokenType][tokenIndex] = lastToken;
tokensByType[tokenType][lastTokenIndex] = 0;
emit TokenRevoked(
issuer,
owner,
tokenType,
_tokenId,
block.timestamp // solium-disable-line security/no-block-members
);
}
/**
* @dev Transfers issuance permissions to another address
*/
function transferIssuer(uint256 _type, address _oldIssuer, address _newIssuer) external {
require(
msg.sender == manager || (msg.sender == _oldIssuer && tokenTypeIssuers[_type] == _oldIssuer),
"Only managers and issuers can transfer issuance of trophies."
);
tokenTypeIssuers[_type] = _newIssuer;
emit IssuanceTransferred(
_type,
_oldIssuer,
_newIssuer,
block.timestamp // solium-disable-line security/no-block-members
);
}
/**
* @dev Transfers all tokens to a new address
*/
function transferAll(uint256 _type, address _oldAddress, address _newAddress) external {
require(
msg.sender == manager || (msg.sender == _oldAddress && tokenTypeIssuers[_type] == _oldAddress),
"Only managers and issuers can transfer all tokens to a new address."
);
for (uint256 i = 0; i < ownedTokens[_oldAddress].length; i++) {
uint256 token = ownedTokens[_oldAddress][i];
removeTokenFrom(_oldAddress, token);
addTokenTo(_newAddress, token);
}
emit TransferAll(_oldAddress, _newAddress, block.timestamp); // solium-disable-line security/no-block-members
}
/**
* @dev Restrict all transfers
*/
function transferFrom(address _from, address _to, uint256 _tokenId) public {
require(false, "Transfers of trophies are not allowed.");
}
/**
* @dev Restrict all transfers
*/
function safeTransferFrom(address _from, address _to, uint256 _tokenId) public {
require(false, "Transfers of trophies are not allowed.");
}
/**
* @dev Restrict all transfers
*/
function setApprovalForAll(address _to, bool _approved) public {
require(false, "Transfers of trophies are not allowed.");
}
/**
* @dev Restrict all transfers
*/
function approve(address _to, uint256 _tokenId) public {
require(false, "Transfers of trophies are not allowed.");
}
/**
* @dev Internal function to mint a new token
* Reverts if the given token ID already exists
* @param _to address the beneficiary that will own the minted token
* @param _tokenId uint256 ID of the token to be minted by the msg.sender
*/
function _mint(address _to, uint256 _tokenId) internal {
super._mint(_to, _tokenId);
allTokensIndex[_tokenId] = allTokens.length;
allTokens.push(_tokenId);
}
/**
* @dev Internal function to burn a specific token
* Reverts if the token does not exist
* @param _owner owner of the token to burn
* @param _tokenId uint256 ID of the token being burned by the msg.sender
*/
function _burn(address _owner, uint256 _tokenId) internal {
super._burn(_owner, _tokenId);
// Reorg all tokens array
uint256 tokenIndex = allTokensIndex[_tokenId];
uint256 lastTokenIndex = allTokens.length.sub(1);
uint256 lastToken = allTokens[lastTokenIndex];
allTokens[tokenIndex] = lastToken;
allTokens[lastTokenIndex] = 0;
allTokens.length--;
allTokensIndex[_tokenId] = 0;
allTokensIndex[lastToken] = tokenIndex;
}
/**
* @dev Internal function to add a token ID to the list of a given address
* @param _to address representing the new owner of the given token ID
* @param _tokenId uint256 ID of the token to be added to the tokens list of the given address
*/
function addTokenTo(address _to, uint256 _tokenId) internal {
super.addTokenTo(_to, _tokenId);
uint256 length = ownedTokens[_to].length;
ownedTokens[_to].push(_tokenId);
ownedTokensIndex[_tokenId] = length;
}
/**
* @dev Internal function to remove a token ID from the list of a given address
* @param _from address representing the previous owner of the given token ID
* @param _tokenId uint256 ID of the token to be removed from the tokens list of the given address
*/
function removeTokenFrom(address _from, uint256 _tokenId) internal {
super.removeTokenFrom(_from, _tokenId);
// To prevent a gap in the array, we store the last token in the index of the token to delete, and
// then delete the last slot.
uint256 tokenIndex = ownedTokensIndex[_tokenId];
uint256 lastTokenIndex = ownedTokens[_from].length.sub(1);
uint256 lastToken = ownedTokens[_from][lastTokenIndex];
ownedTokens[_from][tokenIndex] = lastToken;
// This also deletes the contents at the last position of the array
ownedTokens[_from].length--;
// Note that this will handle single-element arrays. In that case, both tokenIndex and lastTokenIndex are going to
// be zero. Then we can make sure that we will remove _tokenId from the ownedTokens list since we are first swapping
// the lastToken to the first position, and then dropping the element placed in the last position of the list
ownedTokensIndex[_tokenId] = 0;
ownedTokensIndex[lastToken] = tokenIndex;
}
/**
* @dev Converts a uint256 to a decimal string
*/
function uint2str(uint256 i) internal pure returns (string) {
if (i == 0) return "0";
uint256 j = i;
uint256 m = i;
uint256 length;
while (j != 0){
length++;
j /= 10;
}
bytes memory bstr = new bytes(length);
uint256 k = length - 1;
while (m != 0){
bstr[k--] = byte(48 + m % 10);
m /= 10;
}
return string(bstr);
}
}
contract ERC721Receiver {
/**
* @dev Magic value to be returned upon successful reception of an NFT
* Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`,
* which can be also obtained as `ERC721Receiver(0).onERC721Received.selector`
*/
bytes4 internal constant ERC721_RECEIVED = 0x150b7a02;
/**
* @notice Handle the receipt of an NFT
* @dev The ERC721 smart contract calls this function on the recipient
* after a `safetransfer`. This function MAY throw to revert and reject the
* transfer. Return of other than the magic value MUST result in the
* transaction being reverted.
* Note: the contract address is always the message sender.
* @param _operator The address which called `safeTransferFrom` function
* @param _from The address which previously owned the token
* @param _tokenId The NFT identifier which is being transferred
* @param _data Additional data with no specified format
* @return `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
*/
function onERC721Received(
address _operator,
address _from,
uint256 _tokenId,
bytes _data
)
public
returns(bytes4);
}
library strings {
struct slice {
uint _len;
uint _ptr;
}
function memcpy(uint dest, uint src, uint len) private pure {
// Copy word-length chunks while possible
for(; len >= 32; len -= 32) {
assembly {
mstore(dest, mload(src))
}
dest += 32;
src += 32;
}
// Copy remaining bytes
uint mask = 256 ** (32 - len) - 1;
assembly {
let srcpart := and(mload(src), not(mask))
let destpart := and(mload(dest), mask)
mstore(dest, or(destpart, srcpart))
}
}
/*
* @dev Returns a slice containing the entire string.
* @param self The string to make a slice from.
* @return A newly allocated slice containing the entire string.
*/
function toSlice(string memory self) internal pure returns (slice memory) {
uint ptr;
assembly {
ptr := add(self, 0x20)
}
return slice(bytes(self).length, ptr);
}
/*
* @dev Returns the length of a null-terminated bytes32 string.
* @param self The value to find the length of.
* @return The length of the string, from 0 to 32.
*/
function len(bytes32 self) internal pure returns (uint) {
uint ret;
if (self == 0)
return 0;
if (self & 0xffffffffffffffffffffffffffffffff == 0) {
ret += 16;
self = bytes32(uint(self) / 0x100000000000000000000000000000000);
}
if (self & 0xffffffffffffffff == 0) {
ret += 8;
self = bytes32(uint(self) / 0x10000000000000000);
}
if (self & 0xffffffff == 0) {
ret += 4;
self = bytes32(uint(self) / 0x100000000);
}
if (self & 0xffff == 0) {
ret += 2;
self = bytes32(uint(self) / 0x10000);
}
if (self & 0xff == 0) {
ret += 1;
}
return 32 - ret;
}
/*
* @dev Returns a slice containing the entire bytes32, interpreted as a
* null-terminated utf-8 string.
* @param self The bytes32 value to convert to a slice.
* @return A new slice containing the value of the input argument up to the
* first null.
*/
function toSliceB32(bytes32 self) internal pure returns (slice memory ret) {
// Allocate space for `self` in memory, copy it there, and point ret at it
assembly {
let ptr := mload(0x40)
mstore(0x40, add(ptr, 0x20))
mstore(ptr, self)
mstore(add(ret, 0x20), ptr)
}
ret._len = len(self);
}
/*
* @dev Returns a new slice containing the same data as the current slice.
* @param self The slice to copy.
* @return A new slice containing the same data as `self`.
*/
function copy(slice memory self) internal pure returns (slice memory) {
return slice(self._len, self._ptr);
}
/*
* @dev Copies a slice to a new string.
* @param self The slice to copy.
* @return A newly allocated string containing the slice's text.
*/
function toString(slice memory self) internal pure returns (string memory) {
string memory ret = new string(self._len);
uint retptr;
assembly { retptr := add(ret, 32) }
memcpy(retptr, self._ptr, self._len);
return ret;
}
/*
* @dev Returns the length in runes of the slice. Note that this operation
* takes time proportional to the length of the slice; avoid using it
* in loops, and call `slice.empty()` if you only need to know whether
* the slice is empty or not.
* @param self The slice to operate on.
* @return The length of the slice in runes.
*/
function len(slice memory self) internal pure returns (uint l) {
// Starting at ptr-31 means the LSB will be the byte we care about
uint ptr = self._ptr - 31;
uint end = ptr + self._len;
for (l = 0; ptr < end; l++) {
uint8 b;
assembly { b := and(mload(ptr), 0xFF) }
if (b < 0x80) {
ptr += 1;
} else if(b < 0xE0) {
ptr += 2;
} else if(b < 0xF0) {
ptr += 3;
} else if(b < 0xF8) {
ptr += 4;
} else if(b < 0xFC) {
ptr += 5;
} else {
ptr += 6;
}
}
}
/*
* @dev Returns true if the slice is empty (has a length of 0).
* @param self The slice to operate on.
* @return True if the slice is empty, False otherwise.
*/
function empty(slice memory self) internal pure returns (bool) {
return self._len == 0;
}
/*
* @dev Returns a positive number if `other` comes lexicographically after
* `self`, a negative number if it comes before, or zero if the
* contents of the two slices are equal. Comparison is done per-rune,
* on unicode codepoints.
* @param self The first slice to compare.
* @param other The second slice to compare.
* @return The result of the comparison.
*/
function compare(slice memory self, slice memory other) internal pure returns (int) {
uint shortest = self._len;
if (other._len < self._len)
shortest = other._len;
uint selfptr = self._ptr;
uint otherptr = other._ptr;
for (uint idx = 0; idx < shortest; idx += 32) {
uint a;
uint b;
assembly {
a := mload(selfptr)
b := mload(otherptr)
}
if (a != b) {
// Mask out irrelevant bytes and check again
uint256 mask = uint256(-1); // 0xffff...
if(shortest < 32) {
mask = ~(2 ** (8 * (32 - shortest + idx)) - 1);
}
uint256 diff = (a & mask) - (b & mask);
if (diff != 0)
return int(diff);
}
selfptr += 32;
otherptr += 32;
}
return int(self._len) - int(other._len);
}
/*
* @dev Returns true if the two slices contain the same text.
* @param self The first slice to compare.
* @param self The second slice to compare.
* @return True if the slices are equal, false otherwise.
*/
function equals(slice memory self, slice memory other) internal pure returns (bool) {
return compare(self, other) == 0;
}
/*
* @dev Extracts the first rune in the slice into `rune`, advancing the
* slice to point to the next rune and returning `self`.
* @param self The slice to operate on.
* @param rune The slice that will contain the first rune.
* @return `rune`.
*/
function nextRune(slice memory self, slice memory rune) internal pure returns (slice memory) {
rune._ptr = self._ptr;
if (self._len == 0) {
rune._len = 0;
return rune;
}
uint l;
uint b;
// Load the first byte of the rune into the LSBs of b
assembly { b := and(mload(sub(mload(add(self, 32)), 31)), 0xFF) }
if (b < 0x80) {
l = 1;
} else if(b < 0xE0) {
l = 2;
} else if(b < 0xF0) {
l = 3;
} else {
l = 4;
}
// Check for truncated codepoints
if (l > self._len) {
rune._len = self._len;
self._ptr += self._len;
self._len = 0;
return rune;
}
self._ptr += l;
self._len -= l;
rune._len = l;
return rune;
}
/*
* @dev Returns the first rune in the slice, advancing the slice to point
* to the next rune.
* @param self The slice to operate on.
* @return A slice containing only the first rune from `self`.
*/
function nextRune(slice memory self) internal pure returns (slice memory ret) {
nextRune(self, ret);
}
/*
* @dev Returns the number of the first codepoint in the slice.
* @param self The slice to operate on.
* @return The number of the first codepoint in the slice.
*/
function ord(slice memory self) internal pure returns (uint ret) {
if (self._len == 0) {
return 0;
}
uint word;
uint length;
uint divisor = 2 ** 248;
// Load the rune into the MSBs of b
assembly { word:= mload(mload(add(self, 32))) }
uint b = word / divisor;
if (b < 0x80) {
ret = b;
length = 1;
} else if(b < 0xE0) {
ret = b & 0x1F;
length = 2;
} else if(b < 0xF0) {
ret = b & 0x0F;
length = 3;
} else {
ret = b & 0x07;
length = 4;
}
// Check for truncated codepoints
if (length > self._len) {
return 0;
}
for (uint i = 1; i < length; i++) {
divisor = divisor / 256;
b = (word / divisor) & 0xFF;
if (b & 0xC0 != 0x80) {
// Invalid UTF-8 sequence
return 0;
}
ret = (ret * 64) | (b & 0x3F);
}
return ret;
}
/*
* @dev Returns the keccak-256 hash of the slice.
* @param self The slice to hash.
* @return The hash of the slice.
*/
function keccak(slice memory self) internal pure returns (bytes32 ret) {
assembly {
ret := keccak256(mload(add(self, 32)), mload(self))
}
}
/*
* @dev Returns true if `self` starts with `needle`.
* @param self The slice to operate on.
* @param needle The slice to search for.
* @return True if the slice starts with the provided text, false otherwise.
*/
function startsWith(slice memory self, slice memory needle) internal pure returns (bool) {
if (self._len < needle._len) {
return false;
}
if (self._ptr == needle._ptr) {
return true;
}
bool equal;
assembly {
let length := mload(needle)
let selfptr := mload(add(self, 0x20))
let needleptr := mload(add(needle, 0x20))
equal := eq(keccak256(selfptr, length), keccak256(needleptr, length))
}
return equal;
}
/*
* @dev If `self` starts with `needle`, `needle` is removed from the
* beginning of `self`. Otherwise, `self` is unmodified.
* @param self The slice to operate on.
* @param needle The slice to search for.
* @return `self`
*/
function beyond(slice memory self, slice memory needle) internal pure returns (slice memory) {
if (self._len < needle._len) {
return self;
}
bool equal = true;
if (self._ptr != needle._ptr) {
assembly {
let length := mload(needle)
let selfptr := mload(add(self, 0x20))
let needleptr := mload(add(needle, 0x20))
equal := eq(keccak256(selfptr, length), keccak256(needleptr, length))
}
}
if (equal) {
self._len -= needle._len;
self._ptr += needle._len;
}
return self;
}
/*
* @dev Returns true if the slice ends with `needle`.
* @param self The slice to operate on.
* @param needle The slice to search for.
* @return True if the slice starts with the provided text, false otherwise.
*/
function endsWith(slice memory self, slice memory needle) internal pure returns (bool) {
if (self._len < needle._len) {
return false;
}
uint selfptr = self._ptr + self._len - needle._len;
if (selfptr == needle._ptr) {
return true;
}
bool equal;
assembly {
let length := mload(needle)
let needleptr := mload(add(needle, 0x20))
equal := eq(keccak256(selfptr, length), keccak256(needleptr, length))
}
return equal;
}
/*
* @dev If `self` ends with `needle`, `needle` is removed from the
* end of `self`. Otherwise, `self` is unmodified.
* @param self The slice to operate on.
* @param needle The slice to search for.
* @return `self`
*/
function until(slice memory self, slice memory needle) internal pure returns (slice memory) {
if (self._len < needle._len) {
return self;
}
uint selfptr = self._ptr + self._len - needle._len;
bool equal = true;
if (selfptr != needle._ptr) {
assembly {
let length := mload(needle)
let needleptr := mload(add(needle, 0x20))
equal := eq(keccak256(selfptr, length), keccak256(needleptr, length))
}
}
if (equal) {
self._len -= needle._len;
}
return self;
}
// Returns the memory address of the first byte of the first occurrence of
// `needle` in `self`, or the first byte after `self` if not found.
function findPtr(uint selflen, uint selfptr, uint needlelen, uint needleptr) private pure returns (uint) {
uint ptr = selfptr;
uint idx;
if (needlelen <= selflen) {
if (needlelen <= 32) {
bytes32 mask = bytes32(~(2 ** (8 * (32 - needlelen)) - 1));
bytes32 needledata;
assembly { needledata := and(mload(needleptr), mask) }
uint end = selfptr + selflen - needlelen;
bytes32 ptrdata;
assembly { ptrdata := and(mload(ptr), mask) }
while (ptrdata != needledata) {
if (ptr >= end)
return selfptr + selflen;
ptr++;
assembly { ptrdata := and(mload(ptr), mask) }
}
return ptr;
} else {
// For long needles, use hashing
bytes32 hash;
assembly { hash := keccak256(needleptr, needlelen) }
for (idx = 0; idx <= selflen - needlelen; idx++) {
bytes32 testHash;
assembly { testHash := keccak256(ptr, needlelen) }
if (hash == testHash)
return ptr;
ptr += 1;
}
}
}
return selfptr + selflen;
}
// Returns the memory address of the first byte after the last occurrence of
// `needle` in `self`, or the address of `self` if not found.
function rfindPtr(uint selflen, uint selfptr, uint needlelen, uint needleptr) private pure returns (uint) {
uint ptr;
if (needlelen <= selflen) {
if (needlelen <= 32) {
bytes32 mask = bytes32(~(2 ** (8 * (32 - needlelen)) - 1));
bytes32 needledata;
assembly { needledata := and(mload(needleptr), mask) }
ptr = selfptr + selflen - needlelen;
bytes32 ptrdata;
assembly { ptrdata := and(mload(ptr), mask) }
while (ptrdata != needledata) {
if (ptr <= selfptr)
return selfptr;
ptr--;
assembly { ptrdata := and(mload(ptr), mask) }
}
return ptr + needlelen;
} else {
// For long needles, use hashing
bytes32 hash;
assembly { hash := keccak256(needleptr, needlelen) }
ptr = selfptr + (selflen - needlelen);
while (ptr >= selfptr) {
bytes32 testHash;
assembly { testHash := keccak256(ptr, needlelen) }
if (hash == testHash)
return ptr + needlelen;
ptr -= 1;
}
}
}
return selfptr;
}
/*
* @dev Modifies `self` to contain everything from the first occurrence of
* `needle` to the end of the slice. `self` is set to the empty slice
* if `needle` is not found.
* @param self The slice to search and modify.
* @param needle The text to search for.
* @return `self`.
*/
function find(slice memory self, slice memory needle) internal pure returns (slice memory) {
uint ptr = findPtr(self._len, self._ptr, needle._len, needle._ptr);
self._len -= ptr - self._ptr;
self._ptr = ptr;
return self;
}
/*
* @dev Modifies `self` to contain the part of the string from the start of
* `self` to the end of the first occurrence of `needle`. If `needle`
* is not found, `self` is set to the empty slice.
* @param self The slice to search and modify.
* @param needle The text to search for.
* @return `self`.
*/
function rfind(slice memory self, slice memory needle) internal pure returns (slice memory) {
uint ptr = rfindPtr(self._len, self._ptr, needle._len, needle._ptr);
self._len = ptr - self._ptr;
return self;
}
/*
* @dev Splits the slice, setting `self` to everything after the first
* occurrence of `needle`, and `token` to everything before it. If
* `needle` does not occur in `self`, `self` is set to the empty slice,
* and `token` is set to the entirety of `self`.
* @param self The slice to split.
* @param needle The text to search for in `self`.
* @param token An output parameter to which the first token is written.
* @return `token`.
*/
function split(slice memory self, slice memory needle, slice memory token) internal pure returns (slice memory) {
uint ptr = findPtr(self._len, self._ptr, needle._len, needle._ptr);
token._ptr = self._ptr;
token._len = ptr - self._ptr;
if (ptr == self._ptr + self._len) {
// Not found
self._len = 0;
} else {
self._len -= token._len + needle._len;
self._ptr = ptr + needle._len;
}
return token;
}
/*
* @dev Splits the slice, setting `self` to everything after the first
* occurrence of `needle`, and returning everything before it. If
* `needle` does not occur in `self`, `self` is set to the empty slice,
* and the entirety of `self` is returned.
* @param self The slice to split.
* @param needle The text to search for in `self`.
* @return The part of `self` up to the first occurrence of `delim`.
*/
function split(slice memory self, slice memory needle) internal pure returns (slice memory token) {
split(self, needle, token);
}
/*
* @dev Splits the slice, setting `self` to everything before the last
* occurrence of `needle`, and `token` to everything after it. If
* `needle` does not occur in `self`, `self` is set to the empty slice,
* and `token` is set to the entirety of `self`.
* @param self The slice to split.
* @param needle The text to search for in `self`.
* @param token An output parameter to which the first token is written.
* @return `token`.
*/
function rsplit(slice memory self, slice memory needle, slice memory token) internal pure returns (slice memory) {
uint ptr = rfindPtr(self._len, self._ptr, needle._len, needle._ptr);
token._ptr = ptr;
token._len = self._len - (ptr - self._ptr);
if (ptr == self._ptr) {
// Not found
self._len = 0;
} else {
self._len -= token._len + needle._len;
}
return token;
}
/*
* @dev Splits the slice, setting `self` to everything before the last
* occurrence of `needle`, and returning everything after it. If
* `needle` does not occur in `self`, `self` is set to the empty slice,
* and the entirety of `self` is returned.
* @param self The slice to split.
* @param needle The text to search for in `self`.
* @return The part of `self` after the last occurrence of `delim`.
*/
function rsplit(slice memory self, slice memory needle) internal pure returns (slice memory token) {
rsplit(self, needle, token);
}
/*
* @dev Counts the number of nonoverlapping occurrences of `needle` in `self`.
* @param self The slice to search.
* @param needle The text to search for in `self`.
* @return The number of occurrences of `needle` found in `self`.
*/
function count(slice memory self, slice memory needle) internal pure returns (uint cnt) {
uint ptr = findPtr(self._len, self._ptr, needle._len, needle._ptr) + needle._len;
while (ptr <= self._ptr + self._len) {
cnt++;
ptr = findPtr(self._len - (ptr - self._ptr), ptr, needle._len, needle._ptr) + needle._len;
}
}
/*
* @dev Returns True if `self` contains `needle`.
* @param self The slice to search.
* @param needle The text to search for in `self`.
* @return True if `needle` is found in `self`, false otherwise.
*/
function contains(slice memory self, slice memory needle) internal pure returns (bool) {
return rfindPtr(self._len, self._ptr, needle._len, needle._ptr) != self._ptr;
}
/*
* @dev Returns a newly allocated string containing the concatenation of
* `self` and `other`.
* @param self The first slice to concatenate.
* @param other The second slice to concatenate.
* @return The concatenation of the two strings.
*/
function concat(slice memory self, slice memory other) internal pure returns (string memory) {
string memory ret = new string(self._len + other._len);
uint retptr;
assembly { retptr := add(ret, 32) }
memcpy(retptr, self._ptr, self._len);
memcpy(retptr + self._len, other._ptr, other._len);
return ret;
}
/*
* @dev Joins an array of slices, using `self` as a delimiter, returning a
* newly allocated string.
* @param self The delimiter to use.
* @param parts A list of slices to join.
* @return A newly allocated string containing all the slices in `parts`,
* joined with `self`.
*/
function join(slice memory self, slice[] memory parts) internal pure returns (string memory) {
if (parts.length == 0)
return "";
uint length = self._len * (parts.length - 1);
for(uint i = 0; i < parts.length; i++)
length += parts[i]._len;
string memory ret = new string(length);
uint retptr;
assembly { retptr := add(ret, 32) }
for(i = 0; i < parts.length; i++) {
memcpy(retptr, parts[i]._ptr, parts[i]._len);
retptr += parts[i]._len;
if (i < parts.length - 1) {
memcpy(retptr, self._ptr, self._len);
retptr += self._len;
}
}
return ret;
}
}