entryHeader.js 12 KB

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  1. var Utils = require("../util"),
  2. Constants = Utils.Constants;
  3. /* The central directory file header */
  4. module.exports = function () {
  5. var _verMade = 20, // v2.0
  6. _version = 10, // v1.0
  7. _flags = 0,
  8. _method = 0,
  9. _time = 0,
  10. _crc = 0,
  11. _compressedSize = 0,
  12. _size = 0,
  13. _fnameLen = 0,
  14. _extraLen = 0,
  15. _comLen = 0,
  16. _diskStart = 0,
  17. _inattr = 0,
  18. _attr = 0,
  19. _offset = 0;
  20. _verMade |= Utils.isWin ? 0x0a00 : 0x0300;
  21. // Set EFS flag since filename and comment fields are all by default encoded using UTF-8.
  22. // Without it file names may be corrupted for other apps when file names use unicode chars
  23. _flags |= Constants.FLG_EFS;
  24. const _localHeader = {
  25. extraLen: 0
  26. };
  27. // casting
  28. const uint32 = (val) => Math.max(0, val) >>> 0;
  29. const uint16 = (val) => Math.max(0, val) & 0xffff;
  30. const uint8 = (val) => Math.max(0, val) & 0xff;
  31. _time = Utils.fromDate2DOS(new Date());
  32. return {
  33. get made() {
  34. return _verMade;
  35. },
  36. set made(val) {
  37. _verMade = val;
  38. },
  39. get version() {
  40. return _version;
  41. },
  42. set version(val) {
  43. _version = val;
  44. },
  45. get flags() {
  46. return _flags;
  47. },
  48. set flags(val) {
  49. _flags = val;
  50. },
  51. get flags_efs() {
  52. return (_flags & Constants.FLG_EFS) > 0;
  53. },
  54. set flags_efs(val) {
  55. if (val) {
  56. _flags |= Constants.FLG_EFS;
  57. } else {
  58. _flags &= ~Constants.FLG_EFS;
  59. }
  60. },
  61. get flags_desc() {
  62. return (_flags & Constants.FLG_DESC) > 0;
  63. },
  64. set flags_desc(val) {
  65. if (val) {
  66. _flags |= Constants.FLG_DESC;
  67. } else {
  68. _flags &= ~Constants.FLG_DESC;
  69. }
  70. },
  71. get method() {
  72. return _method;
  73. },
  74. set method(val) {
  75. switch (val) {
  76. case Constants.STORED:
  77. this.version = 10;
  78. case Constants.DEFLATED:
  79. default:
  80. this.version = 20;
  81. }
  82. _method = val;
  83. },
  84. get time() {
  85. return Utils.fromDOS2Date(this.timeval);
  86. },
  87. set time(val) {
  88. this.timeval = Utils.fromDate2DOS(val);
  89. },
  90. get timeval() {
  91. return _time;
  92. },
  93. set timeval(val) {
  94. _time = uint32(val);
  95. },
  96. get timeHighByte() {
  97. return uint8(_time >>> 8);
  98. },
  99. get crc() {
  100. return _crc;
  101. },
  102. set crc(val) {
  103. _crc = uint32(val);
  104. },
  105. get compressedSize() {
  106. return _compressedSize;
  107. },
  108. set compressedSize(val) {
  109. _compressedSize = uint32(val);
  110. },
  111. get size() {
  112. return _size;
  113. },
  114. set size(val) {
  115. _size = uint32(val);
  116. },
  117. get fileNameLength() {
  118. return _fnameLen;
  119. },
  120. set fileNameLength(val) {
  121. _fnameLen = val;
  122. },
  123. get extraLength() {
  124. return _extraLen;
  125. },
  126. set extraLength(val) {
  127. _extraLen = val;
  128. },
  129. get extraLocalLength() {
  130. return _localHeader.extraLen;
  131. },
  132. set extraLocalLength(val) {
  133. _localHeader.extraLen = val;
  134. },
  135. get commentLength() {
  136. return _comLen;
  137. },
  138. set commentLength(val) {
  139. _comLen = val;
  140. },
  141. get diskNumStart() {
  142. return _diskStart;
  143. },
  144. set diskNumStart(val) {
  145. _diskStart = uint32(val);
  146. },
  147. get inAttr() {
  148. return _inattr;
  149. },
  150. set inAttr(val) {
  151. _inattr = uint32(val);
  152. },
  153. get attr() {
  154. return _attr;
  155. },
  156. set attr(val) {
  157. _attr = uint32(val);
  158. },
  159. // get Unix file permissions
  160. get fileAttr() {
  161. return (_attr || 0) >> 16 & 0xfff;
  162. },
  163. get offset() {
  164. return _offset;
  165. },
  166. set offset(val) {
  167. _offset = uint32(val);
  168. },
  169. get encrypted() {
  170. return (_flags & Constants.FLG_ENC) === Constants.FLG_ENC;
  171. },
  172. get centralHeaderSize() {
  173. return Constants.CENHDR + _fnameLen + _extraLen + _comLen;
  174. },
  175. get realDataOffset() {
  176. return _offset + Constants.LOCHDR + _localHeader.fnameLen + _localHeader.extraLen;
  177. },
  178. get localHeader() {
  179. return _localHeader;
  180. },
  181. loadLocalHeaderFromBinary: function (/*Buffer*/ input) {
  182. var data = input.slice(_offset, _offset + Constants.LOCHDR);
  183. // 30 bytes and should start with "PK\003\004"
  184. if (data.readUInt32LE(0) !== Constants.LOCSIG) {
  185. throw Utils.Errors.INVALID_LOC();
  186. }
  187. // version needed to extract
  188. _localHeader.version = data.readUInt16LE(Constants.LOCVER);
  189. // general purpose bit flag
  190. _localHeader.flags = data.readUInt16LE(Constants.LOCFLG);
  191. // compression method
  192. _localHeader.method = data.readUInt16LE(Constants.LOCHOW);
  193. // modification time (2 bytes time, 2 bytes date)
  194. _localHeader.time = data.readUInt32LE(Constants.LOCTIM);
  195. // uncompressed file crc-32 valu
  196. _localHeader.crc = data.readUInt32LE(Constants.LOCCRC);
  197. // compressed size
  198. _localHeader.compressedSize = data.readUInt32LE(Constants.LOCSIZ);
  199. // uncompressed size
  200. _localHeader.size = data.readUInt32LE(Constants.LOCLEN);
  201. // filename length
  202. _localHeader.fnameLen = data.readUInt16LE(Constants.LOCNAM);
  203. // extra field length
  204. _localHeader.extraLen = data.readUInt16LE(Constants.LOCEXT);
  205. // read extra data
  206. const extraStart = _offset + Constants.LOCHDR + _localHeader.fnameLen;
  207. const extraEnd = extraStart + _localHeader.extraLen;
  208. return input.slice(extraStart, extraEnd);
  209. },
  210. loadFromBinary: function (/*Buffer*/ data) {
  211. // data should be 46 bytes and start with "PK 01 02"
  212. if (data.length !== Constants.CENHDR || data.readUInt32LE(0) !== Constants.CENSIG) {
  213. throw Utils.Errors.INVALID_CEN();
  214. }
  215. // version made by
  216. _verMade = data.readUInt16LE(Constants.CENVEM);
  217. // version needed to extract
  218. _version = data.readUInt16LE(Constants.CENVER);
  219. // encrypt, decrypt flags
  220. _flags = data.readUInt16LE(Constants.CENFLG);
  221. // compression method
  222. _method = data.readUInt16LE(Constants.CENHOW);
  223. // modification time (2 bytes time, 2 bytes date)
  224. _time = data.readUInt32LE(Constants.CENTIM);
  225. // uncompressed file crc-32 value
  226. _crc = data.readUInt32LE(Constants.CENCRC);
  227. // compressed size
  228. _compressedSize = data.readUInt32LE(Constants.CENSIZ);
  229. // uncompressed size
  230. _size = data.readUInt32LE(Constants.CENLEN);
  231. // filename length
  232. _fnameLen = data.readUInt16LE(Constants.CENNAM);
  233. // extra field length
  234. _extraLen = data.readUInt16LE(Constants.CENEXT);
  235. // file comment length
  236. _comLen = data.readUInt16LE(Constants.CENCOM);
  237. // volume number start
  238. _diskStart = data.readUInt16LE(Constants.CENDSK);
  239. // internal file attributes
  240. _inattr = data.readUInt16LE(Constants.CENATT);
  241. // external file attributes
  242. _attr = data.readUInt32LE(Constants.CENATX);
  243. // LOC header offset
  244. _offset = data.readUInt32LE(Constants.CENOFF);
  245. },
  246. localHeaderToBinary: function () {
  247. // LOC header size (30 bytes)
  248. var data = Buffer.alloc(Constants.LOCHDR);
  249. // "PK\003\004"
  250. data.writeUInt32LE(Constants.LOCSIG, 0);
  251. // version needed to extract
  252. data.writeUInt16LE(_version, Constants.LOCVER);
  253. // general purpose bit flag
  254. data.writeUInt16LE(_flags, Constants.LOCFLG);
  255. // compression method
  256. data.writeUInt16LE(_method, Constants.LOCHOW);
  257. // modification time (2 bytes time, 2 bytes date)
  258. data.writeUInt32LE(_time, Constants.LOCTIM);
  259. // uncompressed file crc-32 value
  260. data.writeUInt32LE(_crc, Constants.LOCCRC);
  261. // compressed size
  262. data.writeUInt32LE(_compressedSize, Constants.LOCSIZ);
  263. // uncompressed size
  264. data.writeUInt32LE(_size, Constants.LOCLEN);
  265. // filename length
  266. data.writeUInt16LE(_fnameLen, Constants.LOCNAM);
  267. // extra field length
  268. data.writeUInt16LE(_localHeader.extraLen, Constants.LOCEXT);
  269. return data;
  270. },
  271. centralHeaderToBinary: function () {
  272. // CEN header size (46 bytes)
  273. var data = Buffer.alloc(Constants.CENHDR + _fnameLen + _extraLen + _comLen);
  274. // "PK\001\002"
  275. data.writeUInt32LE(Constants.CENSIG, 0);
  276. // version made by
  277. data.writeUInt16LE(_verMade, Constants.CENVEM);
  278. // version needed to extract
  279. data.writeUInt16LE(_version, Constants.CENVER);
  280. // encrypt, decrypt flags
  281. data.writeUInt16LE(_flags, Constants.CENFLG);
  282. // compression method
  283. data.writeUInt16LE(_method, Constants.CENHOW);
  284. // modification time (2 bytes time, 2 bytes date)
  285. data.writeUInt32LE(_time, Constants.CENTIM);
  286. // uncompressed file crc-32 value
  287. data.writeUInt32LE(_crc, Constants.CENCRC);
  288. // compressed size
  289. data.writeUInt32LE(_compressedSize, Constants.CENSIZ);
  290. // uncompressed size
  291. data.writeUInt32LE(_size, Constants.CENLEN);
  292. // filename length
  293. data.writeUInt16LE(_fnameLen, Constants.CENNAM);
  294. // extra field length
  295. data.writeUInt16LE(_extraLen, Constants.CENEXT);
  296. // file comment length
  297. data.writeUInt16LE(_comLen, Constants.CENCOM);
  298. // volume number start
  299. data.writeUInt16LE(_diskStart, Constants.CENDSK);
  300. // internal file attributes
  301. data.writeUInt16LE(_inattr, Constants.CENATT);
  302. // external file attributes
  303. data.writeUInt32LE(_attr, Constants.CENATX);
  304. // LOC header offset
  305. data.writeUInt32LE(_offset, Constants.CENOFF);
  306. return data;
  307. },
  308. toJSON: function () {
  309. const bytes = function (nr) {
  310. return nr + " bytes";
  311. };
  312. return {
  313. made: _verMade,
  314. version: _version,
  315. flags: _flags,
  316. method: Utils.methodToString(_method),
  317. time: this.time,
  318. crc: "0x" + _crc.toString(16).toUpperCase(),
  319. compressedSize: bytes(_compressedSize),
  320. size: bytes(_size),
  321. fileNameLength: bytes(_fnameLen),
  322. extraLength: bytes(_extraLen),
  323. commentLength: bytes(_comLen),
  324. diskNumStart: _diskStart,
  325. inAttr: _inattr,
  326. attr: _attr,
  327. offset: _offset,
  328. centralHeaderSize: bytes(Constants.CENHDR + _fnameLen + _extraLen + _comLen)
  329. };
  330. },
  331. toString: function () {
  332. return JSON.stringify(this.toJSON(), null, "\t");
  333. }
  334. };
  335. };