import { AssetProxyId, ERC20ProxyData, ERC721ProxyData, ProxyData } from '@0xproject/types'; import { BigNumber } from '@0xproject/utils'; import BN = require('bn.js'); import ethUtil = require('ethereumjs-util'); import * as _ from 'lodash'; const ERC20_PROXY_METADATA_BYTE_LENGTH = 21; const ERC721_PROXY_METADATA_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; }, encodeERC20ProxyData(tokenAddress: string): string { const encodedAssetProxyId = assetProxyUtils.encodeAssetProxyId(AssetProxyId.ERC20); const encodedAddress = assetProxyUtils.encodeAddress(tokenAddress); const encodedMetadata = Buffer.concat([encodedAddress, encodedAssetProxyId]); const encodedMetadataHex = ethUtil.bufferToHex(encodedMetadata); return encodedMetadataHex; }, decodeERC20ProxyData(proxyData: string): ERC20ProxyData { const encodedProxyMetadata = ethUtil.toBuffer(proxyData); if (encodedProxyMetadata.byteLength !== ERC20_PROXY_METADATA_BYTE_LENGTH) { throw new Error( `Could not decode ERC20 Proxy Data. Expected length of encoded data to be 21. Got ${ encodedProxyMetadata.byteLength }`, ); } const encodedAssetProxyId = encodedProxyMetadata.slice(-1); const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId); if (assetProxyId !== AssetProxyId.ERC20) { throw new Error( `Could not decode ERC20 Proxy Data. Expected Asset Proxy Id to be ERC20 (${ AssetProxyId.ERC20 }), but got ${assetProxyId}`, ); } const addressOffset = ERC20_PROXY_METADATA_BYTE_LENGTH - 1; const encodedTokenAddress = encodedProxyMetadata.slice(0, addressOffset); const tokenAddress = assetProxyUtils.decodeAddress(encodedTokenAddress); const erc20ProxyData = { assetProxyId, tokenAddress, }; return erc20ProxyData; }, encodeERC721ProxyData(tokenAddress: string, tokenId: BigNumber, data?: string): string { const encodedAssetProxyId = assetProxyUtils.encodeAssetProxyId(AssetProxyId.ERC721); const encodedAddress = assetProxyUtils.encodeAddress(tokenAddress); const encodedTokenId = assetProxyUtils.encodeUint256(tokenId); const encodedMetadata = Buffer.concat([encodedAddress, encodedTokenId, encodedAssetProxyId]); if (!_.isUndefined(data)) { const encodedData = ethUtil.toBuffer(data); const dataLength = new BigNumber(encodedData.byteLength); const encodedDataLength = assetProxyUtils.encodeUint256(dataLength); encodedMetadata = Buffer.concat([encodedMetadata, encodedDataLength, encodedData]); } const encodedMetadataHex = ethUtil.bufferToHex(encodedMetadata); return encodedMetadataHex; }, decodeERC721ProxyData(proxyData: string): ERC721ProxyData { const encodedProxyMetadata = ethUtil.toBuffer(proxyData); if (encodedProxyMetadata.byteLength < ERC721_PROXY_METADATA_BYTE_LENGTH) { throw new Error( `Could not decode ERC20 Proxy Data. Expected length of encoded data to be at least 53. Got ${ encodedProxyMetadata.byteLength }`, ); } const encodedAssetProxyId = encodedProxyMetadata.slice(-1); const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId); if (assetProxyId !== AssetProxyId.ERC721) { throw new Error( `Could not decode ERC721 Proxy Data. Expected Asset Proxy Id to be ERC721 (${ AssetProxyId.ERC721 }), but got ${assetProxyId}`, ); } const addressOffset = ERC20_PROXY_METADATA_BYTE_LENGTH - 1; const encodedTokenAddress = encodedProxyMetadata.slice(0, addressOffset); const tokenAddress = assetProxyUtils.decodeAddress(encodedTokenAddress); const tokenIdOffset = ERC721_PROXY_METADATA_BYTE_LENGTH - 1; const encodedTokenId = encodedProxyMetadata.slice(addressOffset, tokenIdOffset); const tokenId = assetProxyUtils.decodeUint256(encodedTokenId); const nullData = '0x'; let data = nullData; if (encodedProxyMetadata.byteLength > 53) { const encodedDataLength = encodedProxyMetadata.slice(53, 85); const dataLength = assetProxyUtils.decodeUint256(encodedDataLength); const expectedDataLength = new BigNumber(encodedProxyMetadata.byteLength - 85); if (!dataLength.equals(expectedDataLength)) { throw new Error( `Data length (${dataLength}) does not match actual length of data (${expectedDataLength})`, ); } const encodedData = encodedProxyMetadata.slice(85); data = ethUtil.bufferToHex(encodedData); } const erc721ProxyData: ERC721ProxyData = { assetProxyId, tokenAddress, tokenId, data, }; return erc721ProxyData; }, decodeProxyDataId(proxyData: string): AssetProxyId { const encodedProxyMetadata = ethUtil.toBuffer(proxyData); if (encodedProxyMetadata.byteLength < 1) { throw new Error( `Could not decode Proxy Data. Expected length of encoded data to be at least 1. Got ${ encodedProxyMetadata.byteLength }`, ); } const encodedAssetProxyId = encodedProxyMetadata.slice(-1); const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId); return assetProxyId; }, decodeProxyData(proxyData: string): ProxyData { const assetProxyId = assetProxyUtils.decodeProxyDataId(proxyData); switch (assetProxyId) { case AssetProxyId.ERC20: const erc20ProxyData = assetProxyUtils.decodeERC20ProxyData(proxyData); const generalizedERC20ProxyData = { assetProxyId, tokenAddress: erc20ProxyData.tokenAddress, }; return generalizedERC20ProxyData; case AssetProxyId.ERC721: const erc721ProxyData = assetProxyUtils.decodeERC721ProxyData(proxyData); const generaliedERC721ProxyData = { assetProxyId, tokenAddress: erc721ProxyData.tokenAddress, data: erc721ProxyData.tokenId, }; return generaliedERC721ProxyData; default: throw new Error(`Unrecognized asset proxy id: ${assetProxyId}`); } }, };