@loaders.gl/3d-tiles/dist/3d-tiles-archive/3d-tiles-archive-archive.js

3D Tiles, an open standard for streaming massive heterogeneous 3D geospatial datasets.

// loaders.gl
// SPDX-License-Identifier: MIT
// Copyright vis.gl contributors
import { MD5Hash } from '@loaders.gl/crypto';
import { DeflateCompression, NoCompression } from '@loaders.gl/compression';
import { IndexedArchive, parseZipLocalFileHeader, readRange } from '@loaders.gl/zip';
/**
 * Handling different compression types in zip
 */
const COMPRESSION_METHODS = {
    /** No compression */
    0: (data) => new NoCompression().decompress(data),
    /** Deflation */
    8: (data) => new DeflateCompression({ raw: true }).decompress(data)
};
/**
 * Class for handling information about 3tz file
 */
export class Tiles3DArchive extends IndexedArchive {
    /** hash info */
    hashTable;
    /**
     * creates Tiles3DArchive handler
     * @param fileProvider - readable file handle with the whole archive
     * @param hashTable - hash info
     */
    constructor(fileProvider, hashTable, fileName) {
        super(fileProvider, hashTable, fileName);
        this.hashTable = hashTable;
    }
    /**
     * Returns file with the given path from 3tz archive
     * @param path - path inside the 3tz
     * @returns buffer with ready to use file
     */
    async getFile(path) {
        // sometimes paths are not in lower case when hash file is created,
        // so first we're looking for lower case file name and then for original one
        let data = await this.getFileBytes(path.toLocaleLowerCase());
        if (!data) {
            data = await this.getFileBytes(path);
        }
        if (!data) {
            throw new Error(`No such file in the archive: ${path}`);
        }
        return data;
    }
    /**
     * Trying to get raw file data by adress
     * @param path - path inside the archive
     * @returns buffer with the raw file data
     */
    async getFileBytes(path) {
        let uncompressedFile;
        if (this.hashTable) {
            const arrayBuffer = new TextEncoder().encode(path).buffer;
            const nameHash = await new MD5Hash().hash(arrayBuffer, 'hex');
            const byteOffset = this.hashTable[nameHash];
            if (byteOffset === undefined) {
                return null;
            }
            const localFileHeader = await parseZipLocalFileHeader(byteOffset, this.file);
            if (!localFileHeader) {
                return null;
            }
            const compressedFile = await readRange(this.file, localFileHeader.fileDataOffset, localFileHeader.fileDataOffset + localFileHeader.compressedSize);
            const compressionMethod = COMPRESSION_METHODS[localFileHeader.compressionMethod];
            if (!compressionMethod) {
                throw Error('Only Deflation compression is supported');
            }
            uncompressedFile = await compressionMethod(compressedFile);
        }
        else {
            uncompressedFile = await this.getFileWithoutHash(path);
        }
        return uncompressedFile;
    }
}
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