apache-arrow/src/builder/fixedsizelist.ts

Apache Arrow columnar in-memory format

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

import { Field } from '../schema.js';
import { Builder } from '../builder.js';
import { DataType, FixedSizeList } from '../type.js';

/** @ignore */
export class FixedSizeListBuilder<T extends DataType = any, TNull = any> extends Builder<FixedSizeList<T>, TNull> {
    public setValue(index: number, value: T['TValue']) {
        const [child] = this.children;
        const start = index * this.stride;
        for (let i = -1, n = value.length; ++i < n;) {
            child.set(start + i, value[i]);
        }
    }
    public addChild(child: Builder<T>, name = '0') {
        if (this.numChildren > 0) {
            throw new Error('FixedSizeListBuilder can only have one child.');
        }
        const childIndex = this.children.push(child);
        this.type = new FixedSizeList(this.type.listSize, new Field(name, child.type, true));
        return childIndex;
    }
}