1+ // SPDX-License-Identifier: MIT
2+ pragma solidity ^ 0.8.18 ;
3+
4+ import "@openzeppelin/contracts/utils/Address.sol " ;
5+ import "@openzeppelin/contracts/utils/Context.sol " ;
6+ import "@openzeppelin/contracts/utils/Strings.sol " ;
7+ import "@openzeppelin/contracts/utils/introspection/ERC165.sol " ;
8+
9+ interface IERC1151Receiver {
10+ function onERC1151Received (address operator , address from , uint256 tokenId , bytes calldata data ) external returns (bytes4 );
11+ }
12+
13+ contract MyERC1151 is Context , ERC165 {
14+ using Address for address ;
15+ using Strings for uint256 ;
16+
17+ string private _name;
18+ string private _symbol;
19+ string private _baseUri;
20+
21+ mapping (uint256 => address ) private _nftOwners;
22+ mapping (address => uint256 ) private _ownerToNFTCount;
23+ mapping (uint256 => address ) private _nftApprovals;
24+ mapping (uint256 => uint256 ) private _nftBalances;
25+ mapping (uint256 => string ) private _nftData;
26+ mapping (address => mapping (address => bool )) private _operatorApprovals;
27+
28+ event Transfer (address indexed from , address indexed to , uint256 indexed tokenId );
29+ event Approval (address indexed owner , address indexed approved , uint256 indexed tokenId );
30+ event ApprovalForAll (address indexed owner , address indexed operator , bool approved );
31+
32+ constructor (
33+ string memory name_ ,
34+ string memory symbol_ ,
35+ string memory baseUri_
36+ ) {
37+ _name = name_;
38+ _symbol = symbol_;
39+ _baseUri = baseUri_;
40+ }
41+
42+ function balanceOf (address owner ) public view virtual returns (uint256 ) {
43+ require (owner != address (0 ), "ERC1151: balance query for the zero address " );
44+ return _ownerToNFTCount[owner];
45+ }
46+
47+ function ownerOf (uint256 tokenId ) public view virtual returns (address ) {
48+ address owner = _nftOwners[tokenId];
49+ require (owner != address (0 ), "ERC1151: owner query for nonexistent token " );
50+ return owner;
51+ }
52+
53+ function name () public view virtual returns (string memory ) {
54+ return _name;
55+ }
56+
57+ function symbol () public view virtual returns (string memory ) {
58+ return _symbol;
59+ }
60+
61+ function tokenURI (uint256 tokenId ) public view virtual returns (string memory ) {
62+ require (_exists (tokenId), "ERC1151: URI query for nonexistent token " );
63+ string memory baseURI = _baseURI ();
64+ return bytes (baseURI).length > 0 ? string (abi.encodePacked (baseURI, tokenId.toString ())) : "" ;
65+ }
66+
67+ function _baseURI () internal view virtual returns (string memory ) {
68+ return _baseUri;
69+ }
70+
71+ function approve (address to , uint256 tokenId ) public virtual {
72+ address owner = ownerOf (tokenId);
73+ require (to != owner, "ERC1151: approval to current owner " );
74+ require (_msgSender () == owner || isApprovedForAll (owner, _msgSender ()), "ERC1151: approve caller is not owner nor approved for all " );
75+ _approve (to, tokenId);
76+ }
77+
78+ function getApproved (uint256 tokenId ) public view virtual returns (address ) {
79+ require (_exists (tokenId), "ERC1151: approved query for nonexistent token " );
80+ return _nftApprovals[tokenId];
81+ }
82+
83+ function setApprovalForAll (address operator , bool approved ) public virtual {
84+ require (operator != _msgSender (), "ERC1151: approve to caller " );
85+ _operatorApprovals[_msgSender ()][operator] = approved;
86+ emit ApprovalForAll (_msgSender (), operator, approved);
87+ }
88+
89+ function isApprovedForAll (address owner , address operator ) public view virtual returns (bool ) {
90+ return _operatorApprovals[owner][operator];
91+ }
92+
93+ function transferFrom (address from , address to , uint256 tokenId ) public virtual {
94+ require (_isApprovedOrOwner (_msgSender (), tokenId), "ERC1151: transfer caller is not owner nor approved " );
95+ _transfer (from, to, tokenId);
96+ }
97+
98+ function safeTransferFrom (address from , address to , uint256 tokenId ) public virtual {
99+ safeTransferFrom (from, to, tokenId, "" );
100+ }
101+
102+ function safeTransferFrom (address from , address to , uint256 tokenId , bytes memory _data ) public virtual {
103+ require (_isApprovedOrOwner (_msgSender (), tokenId), "ERC1151: transfer caller is not owner nor approved " );
104+ _safeTransfer (from, to, tokenId, _data);
105+ }
106+
107+ function _safeTransfer (address from , address to , uint256 tokenId , bytes memory _data ) internal virtual {
108+ _transfer (from, to, tokenId);
109+ require (_checkOnERC1151Received (from, to, tokenId, _data), "ERC1151: transfer to non-ERC1151Receiver implementer " );
110+ }
111+
112+ function _exists (uint256 tokenId ) internal view virtual returns (bool ) {
113+ return _nftOwners[tokenId] != address (0 );
114+ }
115+
116+ function _isApprovedOrOwner (address spender , uint256 tokenId ) internal view virtual returns (bool ) {
117+ require (_exists (tokenId), "ERC1151: operator query for nonexistent token " );
118+ address owner = ownerOf (tokenId);
119+ return (spender == owner || getApproved (tokenId) == spender || isApprovedForAll (owner, spender));
120+ }
121+
122+ function _safeMint (address to , uint256 tokenId ) internal virtual {
123+ _safeMint (to, tokenId, "" );
124+ }
125+
126+ function _safeMint (address to , uint256 tokenId , bytes memory _data ) internal virtual {
127+ _mint (to, tokenId);
128+ require (_checkOnERC1151Received (address (0 ), to, tokenId, _data), "ERC1151: transfer to non-ERC1151Receiver implementer " );
129+ }
130+
131+ function _mint (address to , uint256 tokenId ) internal virtual {
132+ require (to != address (0 ), "ERC1151: mint to the zero address " );
133+ require (! _exists (tokenId), "ERC1151: token already minted " );
134+
135+ _beforeTokenTransfer (address (0 ), to, tokenId);
136+
137+ _nftOwners[tokenId] = to;
138+ _ownerToNFTCount[to] += 1 ;
139+
140+ emit Transfer (address (0 ), to, tokenId);
141+ }
142+
143+ function _burn (uint256 tokenId ) internal virtual {
144+ address owner = ownerOf (tokenId);
145+
146+ _beforeTokenTransfer (owner, address (0 ), tokenId);
147+
148+ // Clear approvals
149+ _approve (address (0 ), tokenId);
150+
151+ _ownerToNFTCount[owner] -= 1 ;
152+ delete _nftOwners[tokenId];
153+
154+ emit Transfer (owner, address (0 ), tokenId);
155+ }
156+
157+ function _transfer (address from , address to , uint256 tokenId ) internal virtual {
158+ require (ownerOf (tokenId) == from, "ERC1151: transfer of token that is not own " );
159+ require (to != address (0 ), "ERC1151: transfer to the zero address " );
160+
161+ _beforeTokenTransfer (from, to, tokenId);
162+
163+ // Clear approvals from the previous owner
164+ _approve (address (0 ), tokenId);
165+
166+ _ownerToNFTCount[from] -= 1 ;
167+ _ownerToNFTCount[to] += 1 ;
168+ _nftOwners[tokenId] = to;
169+
170+ emit Transfer (from, to, tokenId);
171+ }
172+
173+ function _approve (address to , uint256 tokenId ) internal virtual {
174+ _nftApprovals[tokenId] = to;
175+ emit Approval (ownerOf (tokenId), to, tokenId);
176+ }
177+
178+ function _checkOnERC1151Received (address from , address to , uint256 tokenId , bytes memory _data ) private returns (bool ) {
179+ if (to.code.length > 0 ) {
180+ try IERC1151Receiver (to).onERC1151Received (_msgSender (), from, tokenId, _data) returns (bytes4 retval ) {
181+ return retval == IERC1151Receiver .onERC1151Received.selector ;
182+ } catch (bytes memory reason ) {
183+ if (reason.length == 0 ) {
184+ revert ("ERC1151: transfer to non-ERC1151Receiver implementer " );
185+ } else {
186+ assembly {
187+ revert (add (32 , reason), mload (reason))
188+ }
189+ }
190+ }
191+ } else {
192+ return true ;
193+ }
194+ }
195+
196+ function _beforeTokenTransfer (address from , address to , uint256 tokenId ) internal virtual {}
197+ }
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