1 files changed, 50 insertions, 0 deletions
diff --git a/packages/utils/src/abi_encoder/abstract_data_types/dependent_data_type.ts b/packages/utils/src/abi_encoder/abstract_data_types/dependent_data_type.ts
new file mode 100644
index 000000000..e9f390b22
--- /dev/null
+++ b/packages/utils/src/abi_encoder/abstract_data_types/dependent_data_type.ts
@@ -0,0 +1,50 @@
+import { DataItem } from 'ethereum-types';
+import * as ethUtil from 'ethereumjs-util';
+import * as _ from 'lodash';
+
+import { CalldataBlock, DependentCalldataBlock, RawCalldata } from '../calldata';
+import * as Constants from '../constants';
+import { DecodingRules } from '../utils/rules';
+
+import { DataType } from './data_type';
+import { DataTypeFactory } from './interfaces';
+
+export abstract class DependentDataType extends DataType {
+    protected _dependency: DataType;
+    protected _parent: DataType;
+    private readonly _isStatic: boolean;
+
+    public constructor(dataItem: DataItem, factory: DataTypeFactory, dependency: DataType, parent: DataType) {
+        super(dataItem, factory);
+        this._dependency = dependency;
+        this._parent = parent;
+        this._isStatic = true;
+    }
+
+    public generateCalldataBlock(value: any, parentBlock?: CalldataBlock): DependentCalldataBlock {
+        if (parentBlock === undefined) {
+            throw new Error(`DependentDataType requires a parent block to generate its block`);
+        }
+        const dependencyBlock = this._dependency.generateCalldataBlock(value, parentBlock);
+        const name = this.getDataItem().name;
+        const signature = this.getSignature();
+        const parentName = parentBlock === undefined ? '' : parentBlock.getName();
+        const block = new DependentCalldataBlock(name, signature, parentName, dependencyBlock, parentBlock);
+        return block;
+    }
+
+    public generateValue(calldata: RawCalldata, rules: DecodingRules): any {
+        const destinationOffsetBuf = calldata.popWord();
+        const currentOffset = calldata.getOffset();
+        const destinationOffsetRelative = parseInt(ethUtil.bufferToHex(destinationOffsetBuf), Constants.HEX_BASE);
+        const destinationOffsetAbsolute = calldata.toAbsoluteOffset(destinationOffsetRelative);
+        calldata.setOffset(destinationOffsetAbsolute);
+        const value = this._dependency.generateValue(calldata, rules);
+        calldata.setOffset(currentOffset);
+        return value;
+    }
+
+    public isStatic(): boolean {
+        return this._isStatic;
+    }
+}