nufatfs/dist/constructors.js

A new async-friendly library for accessing FAT16 and FAT32 filesystems

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.serializeFatFSDirectoryEntry = exports.newFatFSDirectoryEntry = exports.createFatFSDirectoryEntry = exports.createFatFsInformation = exports.createFatBootInfo = exports.createFat32ExtendedInfo = exports.createBootSectorInfo = void 0;
const utils_1 = require("./utils");
const textDecoder = new TextDecoder();
const textEncoder = new TextEncoder();
function createBootSectorInfo(input, offset) {
    const data = (0, utils_1.structFormatUnpack)("<3x8sHBHBHHBHHHII", input, offset);
    return {
        oemInfo: data[0],
        bytesPerLogicalSector: data[1],
        logicalSectorsPerCluster: data[2],
        reservedLogicalSectors: data[3],
        fatCount: data[4],
        deprecatedMaxRootDirEntries: data[5],
        deprecatedTotalLogicalSectors: data[6],
        mediaDescriptor: data[7],
        deprecatedLogicalSectorsPerFat: data[8],
        physicalSectorsPerTrack: data[9],
        numOfHeads: data[10],
        preceedingHiddenSectors: data[11],
        totalLogicalSectors: data[12],
    };
}
exports.createBootSectorInfo = createBootSectorInfo;
function createFat32ExtendedInfo(input, offset) {
    const data = (0, utils_1.structFormatUnpack)("<IHHIHH12x", input, offset);
    return {
        logicalSectorsPerFat: data[0],
        mirroringFlags: data[1],
        version: data[2],
        rootDirCluster: data[3],
        fsInformationSectorNum: data[4],
        backupSectorNum: data[5],
    };
}
exports.createFat32ExtendedInfo = createFat32ExtendedInfo;
function createFatBootInfo(input, offset) {
    const data = (0, utils_1.structFormatUnpack)("<BxBI11s8s", input, offset);
    return {
        physicalDriveNumber: data[0],
        extendedBootSignature: data[1],
        volumeId: data[2],
        label: data[3],
        fsType: data[4]
    };
}
exports.createFatBootInfo = createFatBootInfo;
function createFatFsInformation(input, offset) {
    const data = (0, utils_1.structFormatUnpack)("<4s480x4sII12x4s", input, offset);
    return {
        signature1: data[0],
        signature2: data[1],
        lastKnownFreeDataClusters: data[2],
        lastKnownAllocatedDataCluster: data[3],
        signature3: data[4],
    };
}
exports.createFatFsInformation = createFatFsInformation;
function createFatFSDirectoryEntry(input, offset) {
    const data = (0, utils_1.structFormatUnpack)("<11sBB5s2sH4sHI", input, offset);
    return {
        filename: data[0],
        attribs: data[1],
        reserved: data[2],
        creationDate: data[3],
        accessedDate: data[4],
        unsafeFirstClusterAddressHigh: data[5],
        writtenDate: data[6],
        unsafeFirstClusterAddressLow: data[7],
        fileSize: data[8],
        _firstCluster: ((data[5] << 16 >>> 0) | (data[7] >>> 0)) >>> 0,
        _filenameStr: textDecoder.decode(data[0]),
        _lfns: 0,
    };
}
exports.createFatFSDirectoryEntry = createFatFSDirectoryEntry;
function newFatFSDirectoryEntry(name83, attribs, rootCluster, fileSize) {
    const firstClusterAddressHigh = (rootCluster & 0xFFFF0000) >>> 16;
    const firstClusterAddressLow = (rootCluster & 0xFFFF) >>> 0;
    return {
        filename: textEncoder.encode(name83),
        attribs,
        reserved: 0,
        creationDate: new Uint8Array(5).fill(0),
        accessedDate: new Uint8Array(2).fill(0),
        unsafeFirstClusterAddressHigh: firstClusterAddressHigh,
        writtenDate: new Uint8Array(4).fill(0),
        unsafeFirstClusterAddressLow: firstClusterAddressLow,
        fileSize,
        _firstCluster: rootCluster,
        _filenameStr: name83,
        _lfns: 0,
    };
}
exports.newFatFSDirectoryEntry = newFatFSDirectoryEntry;
function serializeFatFSDirectoryEntry(input, overrideUnsafeAddresses = true) {
    if (overrideUnsafeAddresses) {
        input.unsafeFirstClusterAddressLow = (input._firstCluster & 0xFFFF) >>> 0;
        input.unsafeFirstClusterAddressHigh = (input._firstCluster & 0xFFFF0000) >>> 16;
    }
    const data = new Uint8Array(32);
    const dataView = new DataView(data.buffer);
    data.set(input._filenameStr === '' ? input.filename : textEncoder.encode(input._filenameStr), 0);
    data[11] = input.attribs;
    data[12] = input.reserved;
    data.set(input.creationDate, 13);
    data.set(input.accessedDate, 18);
    dataView.setUint16(20, input.unsafeFirstClusterAddressHigh, true);
    data.set(input.writtenDate, 22);
    dataView.setUint16(26, input.unsafeFirstClusterAddressLow, true);
    dataView.setUint32(28, input.fileSize, true);
    // 28 + 4 = 32
    return data;
}
exports.serializeFatFSDirectoryEntry = serializeFatFSDirectoryEntry;