1 files changed, 38 insertions, 0 deletions
diff --git a/packages/contracts/src/utils/asset_proxy_utils.ts b/packages/contracts/src/utils/asset_proxy_utils.ts
new file mode 100644
index 000000000..1a7a312dd
--- /dev/null
+++ b/packages/contracts/src/utils/asset_proxy_utils.ts
@@ -0,0 +1,38 @@
+import { BigNumber } from '@0xproject/utils';
+import BN = require('bn.js');
+import ethUtil = require('ethereumjs-util');
+
+import { AssetProxyId } from './types';
+
+export const assetProxyUtils = {
+    encodeAssetProxyId(assetProxyId: AssetProxyId): Buffer {
+        return ethUtil.toBuffer(assetProxyId);
+    },
+    encodeAddress(address: string): Buffer {
+        if (!ethUtil.isValidAddress(address)) {
+            throw new Error(`Invalid Address: ${address}`);
+        }
+        const encodedAddress = ethUtil.toBuffer(address);
+        return encodedAddress;
+    },
+    encodeUint256(value: BigNumber): Buffer {
+        const formattedValue = new BN(value.toString(10));
+        const encodedValue = ethUtil.toBuffer(formattedValue);
+        return encodedValue;
+    },
+    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;
+    },
+    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;
+    },
+};