1 files changed, 79 insertions, 0 deletions
diff --git a/packages/subproviders/src/utils/wallet_utils.ts b/packages/subproviders/src/utils/wallet_utils.ts
new file mode 100644
index 000000000..cd5cd9ba0
--- /dev/null
+++ b/packages/subproviders/src/utils/wallet_utils.ts
@@ -0,0 +1,79 @@
+import ethUtil = require('ethereumjs-util');
+import HDNode = require('hdkey');
+import * as _ from 'lodash';
+
+import { DerivedHDKeyInfo, WalletSubproviderErrors } from '../types';
+
+const DEFAULT_ADDRESS_SEARCH_LIMIT = 1000;
+
+class DerivedHDKeyInfoIterator implements IterableIterator<DerivedHDKeyInfo> {
+    private _parentDerivedKeyInfo: DerivedHDKeyInfo;
+    private _searchLimit: number;
+    private _index: number;
+
+    constructor(initialDerivedKey: DerivedHDKeyInfo, searchLimit: number = DEFAULT_ADDRESS_SEARCH_LIMIT) {
+        this._searchLimit = searchLimit;
+        this._parentDerivedKeyInfo = initialDerivedKey;
+        this._index = 0;
+    }
+
+    public next(): IteratorResult<DerivedHDKeyInfo> {
+        const baseDerivationPath = this._parentDerivedKeyInfo.baseDerivationPath;
+        const derivationIndex = this._index;
+        const fullDerivationPath = `m/${baseDerivationPath}/${derivationIndex}`;
+        const path = `m/${derivationIndex}`;
+        const hdKey = this._parentDerivedKeyInfo.hdKey.derive(path);
+        const address = walletUtils.addressOfHDKey(hdKey);
+        const derivedKey: DerivedHDKeyInfo = {
+            address,
+            hdKey,
+            baseDerivationPath,
+            derivationPath: fullDerivationPath,
+        };
+        const done = this._index === this._searchLimit;
+        this._index++;
+        return {
+            done,
+            value: derivedKey,
+        };
+    }
+
+    public [Symbol.iterator](): IterableIterator<DerivedHDKeyInfo> {
+        return this;
+    }
+}
+
+export const walletUtils = {
+    calculateDerivedHDKeyInfos(parentDerivedKeyInfo: DerivedHDKeyInfo, numberOfKeys: number): DerivedHDKeyInfo[] {
+        const derivedKeys: DerivedHDKeyInfo[] = [];
+        const derivedKeyIterator = new DerivedHDKeyInfoIterator(parentDerivedKeyInfo, numberOfKeys);
+        for (const key of derivedKeyIterator) {
+            derivedKeys.push(key);
+        }
+        return derivedKeys;
+    },
+    findDerivedKeyInfoForAddressIfExists(
+        address: string,
+        parentDerivedKeyInfo: DerivedHDKeyInfo,
+        searchLimit: number,
+    ): DerivedHDKeyInfo | undefined {
+        let matchedKey: DerivedHDKeyInfo | undefined;
+        const derivedKeyIterator = new DerivedHDKeyInfoIterator(parentDerivedKeyInfo, searchLimit);
+        for (const key of derivedKeyIterator) {
+            if (key.address === address) {
+                matchedKey = key;
+                break;
+            }
+        }
+        return matchedKey;
+    },
+    addressOfHDKey(hdKey: HDNode): string {
+        const shouldSanitizePublicKey = true;
+        const derivedPublicKey = hdKey.publicKey;
+        const ethereumAddressUnprefixed = ethUtil
+            .publicToAddress(derivedPublicKey, shouldSanitizePublicKey)
+            .toString('hex');
+        const address = ethUtil.addHexPrefix(ethereumAddressUnprefixed).toLowerCase();
+        return address;
+    },
+};