1 files changed, 46 insertions, 0 deletions
diff --git a/packages/order-utils/src/crypto.ts b/packages/order-utils/src/crypto.ts
new file mode 100644
index 000000000..517ca2840
--- /dev/null
+++ b/packages/order-utils/src/crypto.ts
@@ -0,0 +1,46 @@
+import BN = require('bn.js');
+import ABI = require('ethereumjs-abi');
+import ethUtil = require('ethereumjs-util');
+import * as _ from 'lodash';
+
+export const crypto = {
+    /**
+     * We convert types from JS to Solidity as follows:
+     * BigNumber -> uint256
+     * number -> uint8
+     * string -> string
+     * boolean -> bool
+     * valid Ethereum address -> address
+     */
+    solSHA3(args: any[]): Buffer {
+        return crypto._solHash(args, ABI.soliditySHA3);
+    },
+    solSHA256(args: any[]): Buffer {
+        return crypto._solHash(args, ABI.soliditySHA256);
+    },
+    _solHash(args: any[], hashFunction: (types: string[], values: any[]) => Buffer): Buffer {
+        const argTypes: string[] = [];
+        _.each(args, (arg, i) => {
+            const isNumber = _.isFinite(arg);
+            if (isNumber) {
+                argTypes.push('uint8');
+            } else if (arg.isBigNumber) {
+                argTypes.push('uint256');
+                const base = 10;
+                args[i] = new BN(arg.toString(base), base);
+            } else if (ethUtil.isValidAddress(arg)) {
+                argTypes.push('address');
+            } else if (_.isString(arg)) {
+                argTypes.push('string');
+            } else if (_.isBuffer(arg)) {
+                argTypes.push('bytes');
+            } else if (_.isBoolean(arg)) {
+                argTypes.push('bool');
+            } else {
+                throw new Error(`Unable to guess arg type: ${arg}`);
+            }
+        });
+        const hash = hashFunction(argTypes, args);
+        return hash;
+    },
+};