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import { AssetData, AssetProxyId, ERC20AssetData, ERC721AssetData } from '@0xproject/types';
import { BigNumber } from '@0xproject/utils';
import ethAbi = require('ethereumjs-abi');
import ethUtil = require('ethereumjs-util');
import { constants } from './constants';
export const assetDataUtils = {
/**
* Encodes an ERC20 token address into a hex encoded assetData string, usable in the makerAssetData or
* takerAssetData fields in a 0x order.
* @param tokenAddress The ERC20 token address to encode
* @return The hex encoded assetData string
*/
encodeERC20AssetData(tokenAddress: string): string {
return ethUtil.bufferToHex(ethAbi.simpleEncode('ERC20Token(address)', tokenAddress));
},
/**
* Decodes an ERC20 assetData hex string into it's corresponding ERC20 tokenAddress & assetProxyId
* @param assetData Hex encoded assetData string to decode
* @return An object containing the decoded tokenAddress & assetProxyId
*/
decodeERC20AssetData(assetData: string): ERC20AssetData {
const data = ethUtil.toBuffer(assetData);
if (data.byteLength < constants.ERC20_ASSET_DATA_BYTE_LENGTH) {
throw new Error(
`Could not decode ERC20 Proxy Data. Expected length of encoded data to be at least ${
constants.ERC20_ASSET_DATA_BYTE_LENGTH
}. Got ${data.byteLength}`,
);
}
const assetProxyId = ethUtil.bufferToHex(data.slice(0, constants.SELECTOR_LENGTH));
if (assetProxyId !== AssetProxyId.ERC20) {
throw new Error(
`Could not decode ERC20 Proxy Data. Expected Asset Proxy Id to be ERC20 (${
AssetProxyId.ERC20
}), but got ${assetProxyId}`,
);
}
const [tokenAddress] = ethAbi.rawDecode(['address'], data.slice(constants.SELECTOR_LENGTH));
return {
assetProxyId,
tokenAddress: ethUtil.addHexPrefix(tokenAddress),
};
},
/**
* Encodes an ERC721 token address into a hex encoded assetData string, usable in the makerAssetData or
* takerAssetData fields in a 0x order.
* @param tokenAddress The ERC721 token address to encode
* @param tokenId The ERC721 tokenId to encode
* @return The hex encoded assetData string
*/
encodeERC721AssetData(tokenAddress: string, tokenId: BigNumber): string {
// TODO: Pass `tokendId` as a BigNumber.
return ethUtil.bufferToHex(
ethAbi.simpleEncode(
'ERC721Token(address,uint256)',
tokenAddress,
`0x${tokenId.toString(constants.BASE_16)}`,
),
);
},
/**
* Decodes an ERC721 assetData hex string into it's corresponding ERC721 tokenAddress, tokenId & assetProxyId
* @param assetData Hex encoded assetData string to decode
* @return An object containing the decoded tokenAddress, tokenId & assetProxyId
*/
decodeERC721AssetData(assetData: string): ERC721AssetData {
const data = ethUtil.toBuffer(assetData);
if (data.byteLength < constants.ERC721_ASSET_DATA_MINIMUM_BYTE_LENGTH) {
throw new Error(
`Could not decode ERC721 Asset Data. Expected length of encoded data to be at least ${
constants.ERC721_ASSET_DATA_MINIMUM_BYTE_LENGTH
}. Got ${data.byteLength}`,
);
}
const assetProxyId = ethUtil.bufferToHex(data.slice(0, constants.SELECTOR_LENGTH));
if (assetProxyId !== AssetProxyId.ERC721) {
throw new Error(
`Could not decode ERC721 Asset Data. Expected Asset Proxy Id to be ERC721 (${
AssetProxyId.ERC721
}), but got ${assetProxyId}`,
);
}
const [tokenAddress, tokenId] = ethAbi.rawDecode(['address', 'uint256'], data.slice(constants.SELECTOR_LENGTH));
return {
assetProxyId,
tokenAddress: ethUtil.addHexPrefix(tokenAddress),
tokenId: new BigNumber(tokenId.toString()),
};
},
/**
* Decode and return the assetProxyId from the assetData
* @param assetData Hex encoded assetData string to decode
* @return The assetProxyId
*/
decodeAssetProxyId(assetData: string): AssetProxyId {
const encodedAssetData = ethUtil.toBuffer(assetData);
if (encodedAssetData.byteLength < constants.SELECTOR_LENGTH) {
throw new Error(
`Could not decode assetData. Expected length of encoded data to be at least 4. Got ${
encodedAssetData.byteLength
}`,
);
}
const encodedAssetProxyId = encodedAssetData.slice(0, constants.SELECTOR_LENGTH);
const assetProxyId = decodeAssetProxyId(encodedAssetProxyId);
return assetProxyId;
},
/**
* Decode any assetData into it's corresponding assetData object
* @param assetData Hex encoded assetData string to decode
* @return Either a ERC20 or ERC721 assetData object
*/
decodeAssetDataOrThrow(assetData: string): AssetData {
const assetProxyId = assetDataUtils.decodeAssetProxyId(assetData);
switch (assetProxyId) {
case AssetProxyId.ERC20:
const erc20AssetData = assetDataUtils.decodeERC20AssetData(assetData);
return erc20AssetData;
case AssetProxyId.ERC721:
const erc721AssetData = assetDataUtils.decodeERC721AssetData(assetData);
return erc721AssetData;
default:
throw new Error(`Unrecognized asset proxy id: ${assetProxyId}`);
}
},
};
function decodeAssetProxyId(encodedAssetProxyId: Buffer): AssetProxyId {
const hexString = ethUtil.bufferToHex(encodedAssetProxyId);
if (hexString === AssetProxyId.ERC20) {
return AssetProxyId.ERC20;
}
if (hexString === AssetProxyId.ERC721) {
return AssetProxyId.ERC721;
}
throw new Error(`Invalid ProxyId: ${hexString}`);
}
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