@0x/utils/lib/src/abi_encoder/evm_data_types/string.js

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.StringDataType = void 0;
const ethereum_types_1 = require("ethereum-types");
const ethUtil = require("ethereumjs-util");
const blob_1 = require("../abstract_data_types/types/blob");
const constants_1 = require("../utils/constants");
class StringDataType extends blob_1.AbstractBlobDataType {
    constructor(dataItem, dataTypeFactory) {
        super(dataItem, dataTypeFactory, StringDataType._SIZE_KNOWN_AT_COMPILE_TIME);
        if (!StringDataType.matchType(dataItem.type)) {
            throw new Error(`Tried to instantiate String with bad input: ${dataItem}`);
        }
    }
    static matchType(type) {
        return type === ethereum_types_1.SolidityTypes.String;
    }
    // Disable prefer-function-over-method for inherited abstract methods.
    /* tslint:disable prefer-function-over-method */
    encodeValue(value) {
        // Encoded value is of the form: <length><value>, with each field padded to be word-aligned.
        // 1/3 Construct the value
        const valueBuf = Buffer.from(value);
        const valueLengthInBytes = valueBuf.byteLength;
        const wordsToStoreValuePadded = Math.ceil(valueLengthInBytes / constants_1.constants.EVM_WORD_WIDTH_IN_BYTES);
        const bytesToStoreValuePadded = wordsToStoreValuePadded * constants_1.constants.EVM_WORD_WIDTH_IN_BYTES;
        const valueBufPadded = ethUtil.setLengthRight(valueBuf, bytesToStoreValuePadded);
        // 2/3 Construct the length
        const lengthBuf = ethUtil.toBuffer(valueLengthInBytes);
        const lengthBufPadded = ethUtil.setLengthLeft(lengthBuf, constants_1.constants.EVM_WORD_WIDTH_IN_BYTES);
        // 3/3 Combine length and value
        const encodedValue = Buffer.concat([lengthBufPadded, valueBufPadded]);
        return encodedValue;
    }
    decodeValue(calldata) {
        // Encoded value is of the form: <length><value>, with each field padded to be word-aligned.
        // 1/2 Decode length
        const lengthBufPadded = calldata.popWord();
        const lengthHexPadded = ethUtil.bufferToHex(lengthBufPadded);
        const length = parseInt(lengthHexPadded, constants_1.constants.HEX_BASE);
        // 2/2 Decode value
        const wordsToStoreValuePadded = Math.ceil(length / constants_1.constants.EVM_WORD_WIDTH_IN_BYTES);
        const valueBufPadded = calldata.popWords(wordsToStoreValuePadded);
        const valueBuf = valueBufPadded.slice(0, length);
        const value = valueBuf.toString('UTF-8');
        return value;
    }
    getDefaultValue() {
        return StringDataType._DEFAULT_VALUE;
    }
    getSignatureType() {
        return ethereum_types_1.SolidityTypes.String;
    }
}
exports.StringDataType = StringDataType;
StringDataType._SIZE_KNOWN_AT_COMPILE_TIME = false;
StringDataType._DEFAULT_VALUE = '';
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