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import { AssetProxyId, ERC20ProxyData, ERC721ProxyData, ProxyData } from '@0xproject/types';
import { BigNumber } from '@0xproject/utils';
import BN = require('bn.js');
import ethUtil = require('ethereumjs-util');
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([encodedAssetProxyId, encodedAddress]);
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 ${
encodedProxyMetadata.byteLength
}`,
);
}
const encodedAssetProxyId = encodedProxyMetadata.slice(0, 1);
const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId);
if (assetProxyId !== AssetProxyId.ERC20) {
throw new Error(
`Could not decode ERC20 Proxy Data. Expected Asset Proxy Id to be ERC20 (${
AssetProxyId.ERC20
}), but got ${assetProxyId}`,
);
}
const encodedTokenAddress = encodedProxyMetadata.slice(1, ERC20_PROXY_METADATA_BYTE_LENGTH);
const tokenAddress = assetProxyUtils.decodeAddress(encodedTokenAddress);
const erc20ProxyData = {
assetProxyId,
tokenAddress,
};
return erc20ProxyData;
},
encodeERC721ProxyData(tokenAddress: string, tokenId: BigNumber): string {
const encodedAssetProxyId = assetProxyUtils.encodeAssetProxyId(AssetProxyId.ERC721);
const encodedAddress = assetProxyUtils.encodeAddress(tokenAddress);
const encodedTokenId = assetProxyUtils.encodeUint256(tokenId);
const encodedMetadata = Buffer.concat([encodedAssetProxyId, encodedAddress, encodedTokenId]);
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 53. Got ${
encodedProxyMetadata.byteLength
}`,
);
}
const encodedAssetProxyId = encodedProxyMetadata.slice(0, 1);
const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId);
if (assetProxyId !== AssetProxyId.ERC721) {
throw new Error(
`Could not decode ERC721 Proxy Data. Expected Asset Proxy Id to be ERC721 (${
AssetProxyId.ERC721
}), but got ${assetProxyId}`,
);
}
const addressOffset = 21;
const encodedTokenAddress = encodedProxyMetadata.slice(1, addressOffset);
const tokenAddress = assetProxyUtils.decodeAddress(encodedTokenAddress);
const encodedTokenId = encodedProxyMetadata.slice(addressOffset, ERC721_PROXY_METADATA_BYTE_LENGTH);
const tokenId = assetProxyUtils.decodeUint256(encodedTokenId);
const erc721ProxyData = {
assetProxyId,
tokenAddress,
tokenId,
};
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(0, 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}`);
}
},
};
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