@obsidize/tar-browserify/header/tar-header-utility.js

Browser-based tar utility for packing and unpacking tar files (stream-capable)

import { Constants } from '../common/constants';
import { TarUtility } from '../common/tar-utility';
import { UstarHeaderField } from './ustar/ustar-header-field';
import { UstarHeaderLinkIndicatorType } from './ustar/ustar-header-link-indicator-type';
export var TarHeaderUtility;
(function (TarHeaderUtility) {
    TarHeaderUtility.CHECKSUM_SEED_STRING = ''.padStart(UstarHeaderField.headerChecksum.size, ' ');
    TarHeaderUtility.CHECKSUM_SEED = TarUtility.generateChecksum(TarUtility.encodeString(TarHeaderUtility.CHECKSUM_SEED_STRING));
    TarHeaderUtility.ALL_FIELDS = UstarHeaderField.all();
    TarHeaderUtility.CHECKSUM_FIELDS = UstarHeaderField.checksumSet();
    function isUstarSector(input, offset) {
        return UstarHeaderField.ustarIndicator.sliceString(input, offset).startsWith(Constants.USTAR_TAG);
    }
    TarHeaderUtility.isUstarSector = isUstarSector;
    function isTarHeaderLinkIndicatorTypeDirectory(type) {
        return type === UstarHeaderLinkIndicatorType.DIRECTORY;
    }
    TarHeaderUtility.isTarHeaderLinkIndicatorTypeDirectory = isTarHeaderLinkIndicatorTypeDirectory;
    function isTarHeaderLinkIndicatorTypeFile(type) {
        switch (type) {
            case UstarHeaderLinkIndicatorType.NORMAL_FILE:
            case UstarHeaderLinkIndicatorType.NORMAL_FILE_ALT1:
            case UstarHeaderLinkIndicatorType.NORMAL_FILE_ALT2:
            case UstarHeaderLinkIndicatorType.CONTIGUOUS_FILE:
                return true;
            default:
                return false;
        }
    }
    TarHeaderUtility.isTarHeaderLinkIndicatorTypeFile = isTarHeaderLinkIndicatorTypeFile;
    function isTarHeaderLinkIndicatorTypePax(type) {
        switch (type) {
            case UstarHeaderLinkIndicatorType.LOCAL_EXTENDED_HEADER:
            case UstarHeaderLinkIndicatorType.GLOBAL_EXTENDED_HEADER:
                return true;
            default:
                return false;
        }
    }
    TarHeaderUtility.isTarHeaderLinkIndicatorTypePax = isTarHeaderLinkIndicatorTypePax;
    /**
     * Searches the given input buffer for a USTAR header tar sector, starting at the given offset.
     * Returns -1 if no valid header sector is found.
     */
    function findNextUstarSectorOffset(input, offset = 0) {
        const NOT_FOUND = -1;
        if (!TarUtility.isUint8Array(input)) {
            return NOT_FOUND;
        }
        const maxOffset = input.byteLength;
        let nextOffset = Math.max(0, offset);
        while (nextOffset < maxOffset && !isUstarSector(input, nextOffset)) {
            nextOffset = TarUtility.advanceSectorOffset(nextOffset, maxOffset);
        }
        if (nextOffset < maxOffset) {
            return nextOffset;
        }
        return NOT_FOUND;
    }
    TarHeaderUtility.findNextUstarSectorOffset = findNextUstarSectorOffset;
})(TarHeaderUtility || (TarHeaderUtility = {}));