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import { AssetProxyId, ERC20AssetData, ERC721AssetData } from '@0xproject/types';
import { BigNumber } from '@0xproject/utils';
import BN = require('bn.js');
import ethUtil = require('ethereumjs-util');
const ERC20_ASSET_DATA_BYTE_LENGTH = 36;
const ERC721_ASSET_DATA_MINIMUM_BYTE_LENGTH = 53;
const ASSET_DATA_ADDRESS_OFFSET = 0;
const ERC721_ASSET_DATA_TOKEN_ID_OFFSET = 20;
const ERC721_ASSET_DATA_RECEIVER_DATA_LENGTH_OFFSET = 52;
const ERC721_ASSET_DATA_RECEIVER_DATA_OFFSET = 84;
// TODO: Push upstream to DefinitelyTyped
interface EthAbi {
simpleEncode(signature: string, ...args: any[]): Buffer;
rawDecode(signature: string[], data: Buffer): any[];
}
const ethAbi = require('ethereumjs-abi') as EthAbi;
export const assetProxyUtils = {
encodeAssetProxyId(assetProxyId: AssetProxyId): Buffer {
return ethUtil.toBuffer(assetProxyId);
},
decodeAssetProxyId(encodedAssetProxyId: Buffer): AssetProxyId {
const string = ethUtil.bufferToHex(encodedAssetProxyId);
if (string === AssetProxyId.ERC20) {
return AssetProxyId.ERC20;
}
if (string === AssetProxyId.ERC721) {
return AssetProxyId.ERC721;
}
throw new Error(`Invalid ProxyId: ${string}`);
},
encodeAddress(address: string): Buffer {
if (!ethUtil.isValidAddress(address)) {
throw new Error(`Invalid Address: ${address}`);
}
const encodedAddress = ethUtil.toBuffer(address);
const padded = ethUtil.setLengthLeft(encodedAddress, 32);
return padded;
},
decodeAddress(encodedAddress: Buffer): string {
const unpadded = ethUtil.setLengthLeft(encodedAddress, 20);
const address = ethUtil.bufferToHex(unpadded);
if (!ethUtil.isValidAddress(address)) {
throw new Error(`Invalid Address: ${address}`);
}
return address;
},
encodeUint256(value: BigNumber): Buffer {
const base = 10;
const formattedValue = new BN(value.toString(base));
const encodedValue = ethUtil.toBuffer(formattedValue);
// tslint:disable-next-line:custom-no-magic-numbers
const paddedValue = ethUtil.setLengthLeft(encodedValue, 32);
return paddedValue;
},
decodeUint256(encodedValue: Buffer): BigNumber {
const formattedValue = ethUtil.bufferToHex(encodedValue);
const value = new BigNumber(formattedValue, 16);
return value;
},
encodeERC20AssetData(tokenAddress: string): string {
return ethUtil.bufferToHex(ethAbi.simpleEncode(
'ERC20Token(address)',
tokenAddress,
));
},
decodeERC20AssetData(assetData: string): ERC20AssetData {
const data = ethUtil.toBuffer(assetData);
if (data.byteLength < ERC20_ASSET_DATA_BYTE_LENGTH) {
throw new Error(
`Could not decode ERC20 Proxy Data. Expected length of encoded data to be at least ${ERC20_ASSET_DATA_BYTE_LENGTH}. Got ${data.byteLength}`,
);
}
const assetProxyId = ethUtil.bufferToHex(data.slice(0, 4));
if (assetProxyId !== AssetProxyId.ERC20) {
throw new Error(
`Could not decode ERC20 Proxy Data. Expected Asset Proxy Id to be ERC20 (${AssetProxyId.ERC20}), but got ${assetProxyId}`,
);
}
const [tokenAddress] = ethAbi.rawDecode(['address'], data.slice(4));
return {
assetProxyId,
tokenAddress: ethUtil.addHexPrefix(tokenAddress),
};
},
encodeERC721AssetData(tokenAddress: string, tokenId: BigNumber, receiverData?: string): string {
// TODO: Pass `tokendId` as a BigNumber.
return ethUtil.bufferToHex(ethAbi.simpleEncode(
'ERC721Token(address,uint256,bytes)',
tokenAddress,
'0x' + tokenId.toString(16),
ethUtil.toBuffer(receiverData || '0x'),
));
},
decodeERC721AssetData(assetData: string): ERC721AssetData {
const data = ethUtil.toBuffer(assetData);
if (data.byteLength < ERC721_ASSET_DATA_MINIMUM_BYTE_LENGTH) {
throw new Error(
`Could not decode ERC721 Asset Data. Expected length of encoded data to be at least ${ERC721_ASSET_DATA_MINIMUM_BYTE_LENGTH}. Got ${data.byteLength}`,
);
}
const assetProxyId = ethUtil.bufferToHex(data.slice(0, 4));
if (assetProxyId !== AssetProxyId.ERC721) {
throw new Error(
`Could not decode ERC721 Asset Data. Expected Asset Proxy Id to be ERC721 (${AssetProxyId.ERC721}), but got ${assetProxyId}`,
);
}
const [tokenAddress, tokenId, receiverData] = ethAbi.rawDecode(
['address', 'uint256', 'bytes'],
data.slice(4),
);
return {
assetProxyId,
tokenAddress: ethUtil.addHexPrefix(tokenAddress),
tokenId: new BigNumber(tokenId.toString()),
receiverData: ethUtil.bufferToHex(receiverData),
};
},
decodeAssetDataId(assetData: string): AssetProxyId {
const encodedAssetData = ethUtil.toBuffer(assetData);
if (encodedAssetData.byteLength < 4) {
throw new Error(
`Could not decode Proxy Data. Expected length of encoded data to be at least 4. Got ${encodedAssetData.byteLength}`,
);
}
const encodedAssetProxyId = encodedAssetData.slice(0, 4);
const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId);
return assetProxyId;
},
decodeAssetData(assetData: string): ERC20AssetData | ERC721AssetData {
const assetProxyId = assetProxyUtils.decodeAssetDataId(assetData);
switch (assetProxyId) {
case AssetProxyId.ERC20:
const erc20AssetData = assetProxyUtils.decodeERC20AssetData(assetData);
return erc20AssetData;
case AssetProxyId.ERC721:
const erc721AssetData = assetProxyUtils.decodeERC721AssetData(assetData);
return erc721AssetData;
default:
throw new Error(`Unrecognized asset proxy id: ${assetProxyId}`);
}
},
};
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