实现快传，完善快传和网盘的功能，实现文件的互传等一系列功能

front/src/lib/transfer-archive.ts

@@ -0,0 +1,171 @@
+export interface TransferArchiveEntry {
+  name: string;
+  relativePath?: string;
+  data: Uint8Array | ArrayBuffer | Blob;
+  lastModified?: number;
+}
+
+const ZIP_UTF8_FLAG = 0x0800;
+const CRC32_TABLE = createCrc32Table();
+
+function createCrc32Table() {
+  const table = new Uint32Array(256);
+
+  for (let index = 0; index < 256; index += 1) {
+    let value = index;
+    for (let bit = 0; bit < 8; bit += 1) {
+      value = (value & 1) === 1 ? (0xEDB88320 ^ (value >>> 1)) : (value >>> 1);
+    }
+    table[index] = value >>> 0;
+  }
+
+  return table;
+}
+
+function sanitizeArchivePath(entry: TransferArchiveEntry) {
+  const rawPath = entry.relativePath?.trim() || entry.name;
+  const normalizedPath = rawPath
+    .replaceAll('\\', '/')
+    .split('/')
+    .map((segment) => segment.trim())
+    .filter(Boolean)
+    .join('/');
+
+  return normalizedPath || entry.name;
+}
+
+function crc32(bytes: Uint8Array) {
+  let value = 0xFFFFFFFF;
+
+  for (const byte of bytes) {
+    value = CRC32_TABLE[(value ^ byte) & 0xFF] ^ (value >>> 8);
+  }
+
+  return (value ^ 0xFFFFFFFF) >>> 0;
+}
+
+function toDosDateTime(timestamp: number) {
+  const date = new Date(timestamp);
+  const year = Math.max(1980, date.getFullYear());
+  const month = date.getMonth() + 1;
+  const day = date.getDate();
+  const hours = date.getHours();
+  const minutes = date.getMinutes();
+  const seconds = Math.floor(date.getSeconds() / 2);
+
+  return {
+    time: (hours << 11) | (minutes << 5) | seconds,
+    date: ((year - 1980) << 9) | (month << 5) | day,
+  };
+}
+
+function writeUint16(view: DataView, offset: number, value: number) {
+  view.setUint16(offset, value, true);
+}
+
+function writeUint32(view: DataView, offset: number, value: number) {
+  view.setUint32(offset, value >>> 0, true);
+}
+
+function concatUint8Arrays(chunks: Uint8Array[]) {
+  const totalLength = chunks.reduce((sum, chunk) => sum + chunk.byteLength, 0);
+  const output = new Uint8Array(totalLength);
+  let offset = 0;
+
+  for (const chunk of chunks) {
+    output.set(chunk, offset);
+    offset += chunk.byteLength;
+  }
+
+  return output;
+}
+
+async function normalizeArchiveData(data: TransferArchiveEntry['data']) {
+  if (data instanceof Uint8Array) {
+    return data;
+  }
+
+  if (data instanceof Blob) {
+    return new Uint8Array(await data.arrayBuffer());
+  }
+
+  return new Uint8Array(data);
+}
+
+export function buildTransferArchiveFileName(baseName: string) {
+  return baseName.toLowerCase().endsWith('.zip') ? baseName : `${baseName}.zip`;
+}
+
+export async function createTransferZipArchive(entries: TransferArchiveEntry[]) {
+  const encoder = new TextEncoder();
+  const fileSections: Uint8Array[] = [];
+  const centralDirectorySections: Uint8Array[] = [];
+  let offset = 0;
+
+  for (const entry of entries) {
+    const fileName = sanitizeArchivePath(entry);
+    const fileNameBytes = encoder.encode(fileName);
+    const fileData = await normalizeArchiveData(entry.data);
+    const checksum = crc32(fileData);
+    const {time, date} = toDosDateTime(entry.lastModified ?? Date.now());
+
+    const localHeader = new Uint8Array(30);
+    const localHeaderView = new DataView(localHeader.buffer);
+    writeUint32(localHeaderView, 0, 0x04034B50);
+    writeUint16(localHeaderView, 4, 20);
+    writeUint16(localHeaderView, 6, ZIP_UTF8_FLAG);
+    writeUint16(localHeaderView, 8, 0);
+    writeUint16(localHeaderView, 10, time);
+    writeUint16(localHeaderView, 12, date);
+    writeUint32(localHeaderView, 14, checksum);
+    writeUint32(localHeaderView, 18, fileData.byteLength);
+    writeUint32(localHeaderView, 22, fileData.byteLength);
+    writeUint16(localHeaderView, 26, fileNameBytes.byteLength);
+    writeUint16(localHeaderView, 28, 0);
+
+    fileSections.push(localHeader, fileNameBytes, fileData);
+
+    const centralHeader = new Uint8Array(46);
+    const centralHeaderView = new DataView(centralHeader.buffer);
+    writeUint32(centralHeaderView, 0, 0x02014B50);
+    writeUint16(centralHeaderView, 4, 20);
+    writeUint16(centralHeaderView, 6, 20);
+    writeUint16(centralHeaderView, 8, ZIP_UTF8_FLAG);
+    writeUint16(centralHeaderView, 10, 0);
+    writeUint16(centralHeaderView, 12, time);
+    writeUint16(centralHeaderView, 14, date);
+    writeUint32(centralHeaderView, 16, checksum);
+    writeUint32(centralHeaderView, 20, fileData.byteLength);
+    writeUint32(centralHeaderView, 24, fileData.byteLength);
+    writeUint16(centralHeaderView, 28, fileNameBytes.byteLength);
+    writeUint16(centralHeaderView, 30, 0);
+    writeUint16(centralHeaderView, 32, 0);
+    writeUint16(centralHeaderView, 34, 0);
+    writeUint16(centralHeaderView, 36, 0);
+    writeUint32(centralHeaderView, 38, 0);
+    writeUint32(centralHeaderView, 42, offset);
+
+    centralDirectorySections.push(centralHeader, fileNameBytes);
+    offset += localHeader.byteLength + fileNameBytes.byteLength + fileData.byteLength;
+  }
+
+  const centralDirectory = concatUint8Arrays(centralDirectorySections);
+  const endRecord = new Uint8Array(22);
+  const endRecordView = new DataView(endRecord.buffer);
+  writeUint32(endRecordView, 0, 0x06054B50);
+  writeUint16(endRecordView, 4, 0);
+  writeUint16(endRecordView, 6, 0);
+  writeUint16(endRecordView, 8, entries.length);
+  writeUint16(endRecordView, 10, entries.length);
+  writeUint32(endRecordView, 12, centralDirectory.byteLength);
+  writeUint32(endRecordView, 16, offset);
+  writeUint16(endRecordView, 20, 0);
+
+  return new Blob([
+    concatUint8Arrays(fileSections),
+    centralDirectory,
+    endRecord,
+  ], {
+    type: 'application/zip',
+  });
+}