Rename assetProxyUtils to assetDataUtils

1 files changed, 131 insertions, 0 deletions

diff --git a/packages/order-utils/src/asset_data_utils.ts b/packages/order-utils/src/asset_data_utils.ts
new file mode 100644
index 000000000..81e34218f
--- /dev/null
+++ b/packages/order-utils/src/asset_data_utils.ts
@@ -0,0 +1,131 @@
+import { AssetProxyId, ERC20AssetData, ERC721AssetData } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import BN = require('bn.js');
+import ethUtil = require('ethereumjs-util');
+
+import { constants } from './constants';
+
+// TODO: Push upstream to DefinitelyTyped
+interface EthAbi {
+    simpleEncode(signature: string, ...args: any[]): Buffer;
+    rawDecode(signature: string[], data: Buffer): any[];
+}
+// tslint:disable:no-var-requires
+const ethAbi = require('ethereumjs-abi') as EthAbi;
+
+export const assetDataUtils = {
+    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, constants.WORD_LENGTH);
+        return paddedValue;
+    },
+    decodeUint256(encodedValue: Buffer): BigNumber {
+        const formattedValue = ethUtil.bufferToHex(encodedValue);
+        const value = new BigNumber(formattedValue, constants.BASE_16);
+        return value;
+    },
+    encodeERC20AssetData(tokenAddress: string): string {
+        return ethUtil.bufferToHex(ethAbi.simpleEncode('ERC20Token(address)', tokenAddress));
+    },
+    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 ${assetProxyId}`,
+            );
+        }
+        const [tokenAddress] = ethAbi.rawDecode(['address'], data.slice(constants.SELECTOR_LENGTH));
+        return {
+            assetProxyId,
+            tokenAddress: ethUtil.addHexPrefix(tokenAddress),
+        };
+    },
+    encodeERC721AssetData(tokenAddress: string, tokenId: BigNumber, receiverData?: string): string {
+        // TODO: Pass `tokendId` as a BigNumber.
+        return ethUtil.bufferToHex(
+            ethAbi.simpleEncode(
+                'ERC721Token(address,uint256,bytes)',
+                tokenAddress,
+                `0x${tokenId.toString(constants.BASE_16)}`,
+                ethUtil.toBuffer(receiverData || '0x'),
+            ),
+        );
+    },
+    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, receiverData] = ethAbi.rawDecode(
+            ['address', 'uint256', 'bytes'],
+            data.slice(constants.SELECTOR_LENGTH),
+        );
+        return {
+            assetProxyId,
+            tokenAddress: ethUtil.addHexPrefix(tokenAddress),
+            tokenId: new BigNumber(tokenId.toString()),
+            receiverData: ethUtil.bufferToHex(receiverData),
+        };
+    },
+    decodeAssetDataId(assetData: string): AssetProxyId {
+        const encodedAssetData = ethUtil.toBuffer(assetData);
+        if (encodedAssetData.byteLength < constants.SELECTOR_LENGTH) {
+            throw new Error(
+                `Could not decode Proxy Data. Expected length of encoded data to be at least 4. Got ${
+                    encodedAssetData.byteLength
+                }`,
+            );
+        }
+        const encodedAssetProxyId = encodedAssetData.slice(0, constants.SELECTOR_LENGTH);
+        const assetProxyId = assetDataUtils._decodeAssetProxyId(encodedAssetProxyId);
+        return assetProxyId;
+    },
+    decodeAssetData(assetData: string): ERC20AssetData | ERC721AssetData {
+        const assetProxyId = assetDataUtils.decodeAssetDataId(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}`);
+        }
+    },
+    _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}`);
+    },
+};