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import { DataItem } from 'ethereum-types';
import * as ethUtil from 'ethereumjs-util';
import * as _ from 'lodash';
import { DataTypeFactory, PayloadDataType } from '../abstract_data_types';
import { RawCalldata } from '../calldata';
import * as Constants from '../utils/constants';
export class StaticBytes extends PayloadDataType {
private static readonly _SIZE_KNOWN_AT_COMPILE_TIME: boolean = true;
private static readonly _MATCHER = RegExp(
'^(byte|bytes(1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31|32))$',
);
private static readonly _DEFAULT_WIDTH = 1;
private readonly _width: number;
public static matchType(type: string): boolean {
return StaticBytes._MATCHER.test(type);
}
private static _decodeWidthFromType(type: string): number {
const matches = StaticBytes._MATCHER.exec(type);
const width = (matches !== null && matches.length === 3 && matches[2] !== undefined)
? parseInt(matches[2], Constants.DEC_BASE)
: StaticBytes._DEFAULT_WIDTH;
return width;
}
public constructor(dataItem: DataItem, dataTypeFactory: DataTypeFactory) {
super(dataItem, dataTypeFactory, StaticBytes._SIZE_KNOWN_AT_COMPILE_TIME);
if (!StaticBytes.matchType(dataItem.type)) {
throw new Error(`Tried to instantiate Static Bytes with bad input: ${dataItem}`);
}
this._width = StaticBytes._decodeWidthFromType(dataItem.type);
}
public getSignature(): string {
// Note that `byte` reduces to `bytes1`
return `bytes${this._width}`;
}
public encodeValue(value: string | Buffer): Buffer {
// 1/2 Convert value into a buffer and do bounds checking
this._sanityCheckValue(value);
const valueBuf = ethUtil.toBuffer(value);
// 2/2 Store value as hex
const valuePadded = ethUtil.setLengthRight(valueBuf, Constants.EVM_WORD_WIDTH_IN_BYTES);
return valuePadded;
}
public decodeValue(calldata: RawCalldata): string {
const valueBufPadded = calldata.popWord();
const valueBuf = valueBufPadded.slice(0, this._width);
const value = ethUtil.bufferToHex(valueBuf);
this._sanityCheckValue(value);
return value;
}
private _sanityCheckValue(value: string | Buffer): void {
if (typeof value === 'string') {
if (!value.startsWith('0x')) {
throw new Error(`Tried to encode non-hex value. Value must inlcude '0x' prefix.`);
} else if (value.length % 2 !== 0) {
throw new Error(`Tried to assign ${value}, which is contains a half-byte. Use full bytes only.`);
}
}
const valueBuf = ethUtil.toBuffer(value);
if (valueBuf.byteLength > this._width) {
throw new Error(
`Tried to assign ${value} (${
valueBuf.byteLength
} bytes), which exceeds max bytes that can be stored in a ${this.getSignature()}`,
);
}
}
}
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