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import * as ethUtil from 'ethereumjs-util';
import * as _ from 'lodash';
import { constants } from '../../utils/constants';
import { CalldataBlock } from '../calldata_block';
export class Pointer extends CalldataBlock {
public static readonly RAW_DATA_START = new Buffer('<');
public static readonly RAW_DATA_END = new Buffer('>');
private static readonly _DEPENDENT_PAYLOAD_SIZE_IN_BYTES = 32;
private static readonly _EMPTY_HEADER_SIZE = 0;
private readonly _parent: CalldataBlock;
private readonly _dependency: CalldataBlock;
private _aliasFor: CalldataBlock | undefined;
constructor(name: string, signature: string, parentName: string, dependency: CalldataBlock, parent: CalldataBlock) {
const headerSizeInBytes = Pointer._EMPTY_HEADER_SIZE;
const bodySizeInBytes = Pointer._DEPENDENT_PAYLOAD_SIZE_IN_BYTES;
super(name, signature, parentName, headerSizeInBytes, bodySizeInBytes);
this._parent = parent;
this._dependency = dependency;
this._aliasFor = undefined;
}
public toBuffer(): Buffer {
const destinationOffset =
!_.isUndefined(this._aliasFor) ? this._aliasFor.getOffsetInBytes() : this._dependency.getOffsetInBytes();
const parentOffset = this._parent.getOffsetInBytes();
const parentHeaderSize = this._parent.getHeaderSizeInBytes();
const pointer: number = destinationOffset - (parentOffset + parentHeaderSize);
const pointerHex = `0x${pointer.toString(constants.HEX_BASE)}`;
const pointerBuf = ethUtil.toBuffer(pointerHex);
const pointerBufPadded = ethUtil.setLengthLeft(pointerBuf, constants.EVM_WORD_WIDTH_IN_BYTES);
return pointerBufPadded;
}
public getDependency(): CalldataBlock {
return this._dependency;
}
public setAlias(block: CalldataBlock): void {
this._aliasFor = block;
this._setName(`${this.getName()} (alias for ${block.getName()})`);
}
public getAlias(): CalldataBlock | undefined {
return this._aliasFor;
}
public getRawData(): Buffer {
const dependencyRawData = this._dependency.getRawData();
const rawDataComponents: Buffer[] = [];
rawDataComponents.push(Pointer.RAW_DATA_START);
rawDataComponents.push(dependencyRawData);
rawDataComponents.push(Pointer.RAW_DATA_END);
const rawData = Buffer.concat(rawDataComponents);
return rawData;
}
}
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