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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');
import * as _ from 'lodash';
const ERC20_ASSET_DATA_BYTE_LENGTH = 21;
const ERC721_ASSET_DATA_BYTE_LENGTH = 53;
export const assetProxyUtils = {
encodeAssetProxyId(assetProxyId: AssetProxyId): Buffer {
return ethUtil.toBuffer(assetProxyId);
},
decodeAssetProxyId(encodedAssetProxyId: Buffer): AssetProxyId {
return ethUtil.bufferToInt(encodedAssetProxyId);
},
encodeAddress(address: string): Buffer {
if (!ethUtil.isValidAddress(address)) {
throw new Error(`Invalid Address: ${address}`);
}
const encodedAddress = ethUtil.toBuffer(address);
return encodedAddress;
},
decodeAddress(encodedAddress: Buffer): string {
const address = ethUtil.bufferToHex(encodedAddress);
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 {
const encodedAssetProxyId = assetProxyUtils.encodeAssetProxyId(AssetProxyId.ERC20);
const encodedAddress = assetProxyUtils.encodeAddress(tokenAddress);
const encodedAssetData = Buffer.concat([encodedAddress, encodedAssetProxyId]);
const encodedAssetDataHex = ethUtil.bufferToHex(encodedAssetData);
return encodedAssetDataHex;
},
decodeERC20AssetData(proxyData: string): ERC20AssetData {
const encodedAssetData = ethUtil.toBuffer(proxyData);
if (encodedAssetData.byteLength !== ERC20_ASSET_DATA_BYTE_LENGTH) {
throw new Error(
`Could not decode ERC20 Proxy Data. Expected length of encoded data to be 21. Got ${
encodedAssetData.byteLength
}`,
);
}
const encodedAssetProxyId = encodedAssetData.slice(-1);
const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId);
if (assetProxyId !== AssetProxyId.ERC20) {
throw new Error(
`Could not decode ERC20 Proxy Data. Expected Asset Proxy Id to be ERC20 (${
AssetProxyId.ERC20
}), but got ${assetProxyId}`,
);
}
const addressOffset = ERC20_ASSET_DATA_BYTE_LENGTH - 1;
const encodedTokenAddress = encodedAssetData.slice(0, addressOffset);
const tokenAddress = assetProxyUtils.decodeAddress(encodedTokenAddress);
const erc20AssetData = {
assetProxyId,
tokenAddress,
};
return erc20AssetData;
},
encodeERC721AssetData(tokenAddress: string, tokenId: BigNumber, receiverData?: string): string {
const encodedAssetProxyId = assetProxyUtils.encodeAssetProxyId(AssetProxyId.ERC721);
const encodedAddress = assetProxyUtils.encodeAddress(tokenAddress);
const encodedTokenId = assetProxyUtils.encodeUint256(tokenId);
let encodedAssetData = Buffer.concat([encodedAddress, encodedTokenId]);
if (!_.isUndefined(receiverData)) {
const encodedReceiverData = ethUtil.toBuffer(receiverData);
const receiverDataLength = new BigNumber(encodedReceiverData.byteLength);
const encodedReceiverDataLength = assetProxyUtils.encodeUint256(receiverDataLength);
encodedAssetData = Buffer.concat([encodedAssetData, encodedReceiverDataLength, encodedReceiverData]);
}
encodedAssetData = Buffer.concat([encodedAssetData, encodedAssetProxyId]);
const encodedAssetDataHex = ethUtil.bufferToHex(encodedAssetData);
return encodedAssetDataHex;
},
decodeERC721AssetData(assetData: string): ERC721AssetData {
const encodedAssetData = ethUtil.toBuffer(assetData);
if (encodedAssetData.byteLength < ERC721_ASSET_DATA_BYTE_LENGTH) {
throw new Error(
`Could not decode ERC20 Proxy Data. Expected length of encoded data to be at least 53. Got ${
encodedAssetData.byteLength
}`,
);
}
const addressOffset = 0;
const tokenIdOffset = 20;
const receiverDataLengthOffset = 52;
const receiverDataOffset = 84;
const encodedTokenAddress = encodedAssetData.slice(addressOffset, tokenIdOffset);
const proxyIdOffset = encodedAssetData.byteLength - 1;
const encodedAssetProxyId = encodedAssetData.slice(-1);
const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId);
if (assetProxyId !== AssetProxyId.ERC721) {
throw new Error(
`Could not decode ERC721 Proxy Data. Expected Asset Proxy Id to be ERC721 (${
AssetProxyId.ERC721
}), but got ${assetProxyId}`,
);
}
const tokenAddress = assetProxyUtils.decodeAddress(encodedTokenAddress);
const encodedTokenId = encodedAssetData.slice(tokenIdOffset, receiverDataLengthOffset);
const tokenId = assetProxyUtils.decodeUint256(encodedTokenId);
const nullData = '0x';
let receiverData = nullData;
const lengthUpToReceiverDataLength = receiverDataLengthOffset + 1;
if (encodedAssetData.byteLength > lengthUpToReceiverDataLength) {
const encodedReceiverDataLength = encodedAssetData.slice(receiverDataLengthOffset, receiverDataOffset);
const receiverDataLength = assetProxyUtils.decodeUint256(encodedReceiverDataLength);
const lengthUpToReceiverData = receiverDataOffset + 1;
const expectedReceiverDataLength = new BigNumber(encodedAssetData.byteLength - lengthUpToReceiverData);
if (!receiverDataLength.equals(expectedReceiverDataLength)) {
throw new Error(
`Data length (${receiverDataLength}) does not match actual length of data (${expectedReceiverDataLength})`,
);
}
const encodedReceiverData = encodedAssetData.slice(
receiverDataOffset,
receiverDataOffset + receiverDataLength.toNumber(),
);
receiverData = ethUtil.bufferToHex(encodedReceiverData);
}
const erc721AssetData: ERC721AssetData = {
assetProxyId,
tokenAddress,
tokenId,
receiverData,
};
return erc721AssetData;
},
decodeAssetDataId(assetData: string): AssetProxyId {
const encodedAssetData = ethUtil.toBuffer(assetData);
if (encodedAssetData.byteLength < 1) {
throw new Error(
`Could not decode Proxy Data. Expected length of encoded data to be at least 1. Got ${
encodedAssetData.byteLength
}`,
);
}
const encodedAssetProxyId = encodedAssetData.slice(-1);
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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