untar = function() { "use strict"; /* globals postMessage: false, DataView: false, self: false, window: false, ArrayBuffer: false, Uint8Array: false */ // Source: https://gist.github.com/pascaldekloe/62546103a1576803dade9269ccf76330 // Unmarshals an Uint8Array to string. function decodeUTF8(bytes) { var s = ''; var i = 0; while (i < bytes.length) { var c = bytes[i++]; if (c > 127) { if (c > 191 && c < 224) { if (i >= bytes.length) throw 'UTF-8 decode: incomplete 2-byte sequence'; c = ((c & 31) << 6) | (bytes[i] & 63); } else if (c > 223 && c < 240) { if (i + 1 >= bytes.length) throw 'UTF-8 decode: incomplete 3-byte sequence'; c = ((c & 15) << 12) | ((bytes[i] & 63) << 6) | (bytes[++i] & 63); } else if (c > 239 && c < 248) { if (i + 2 >= bytes.length) throw 'UTF-8 decode: incomplete 4-byte sequence'; c = ((c & 7) << 18) | ((bytes[i] & 63) << 12) | ((bytes[++i] & 63) << 6) | (bytes[++i] & 63); } else throw 'UTF-8 decode: unknown multibyte start 0x' + c.toString(16) + ' at index ' + (i - 1); ++i; } if (c <= 0xffff) s += String.fromCharCode(c); else if (c <= 0x10ffff) { c -= 0x10000; s += String.fromCharCode((c >> 10) | 0xd800); s += String.fromCharCode((c & 0x3FF) | 0xdc00); } else throw 'UTF-8 decode: code point 0x' + c.toString(16) + ' exceeds UTF-16 reach'; } return s; } function PaxHeader(fields) { this._fields = fields; } PaxHeader.parse = function(buffer) { // https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.3.0/com.ibm.zos.v2r3.bpxa500/paxex.htm // An extended header shall consist of one or more records, each constructed as follows: // "%d %s=%s\n", , , // The extended header records shall be encoded according to the ISO/IEC10646-1:2000 standard (UTF-8). // The field, , equals sign, and shown shall be limited to the portable character set, as // encoded in UTF-8. The and fields can be any UTF-8 characters. The field shall be the // decimal length of the extended header record in octets, including the trailing . var bytes = new Uint8Array(buffer); var fields = []; while (bytes.length > 0) { // Decode bytes up to the first space character; that is the total field length var fieldLength = parseInt( decodeUTF8(bytes.subarray(0, bytes.indexOf(0x20))) ); var fieldText = decodeUTF8(bytes.subarray(0, fieldLength)); var fieldMatch = fieldText.match(/^\d+ ([^=]+)=(.*)\n$/); if (fieldMatch === null) { throw new Error("Invalid PAX header data format."); } var fieldName = fieldMatch[1]; var fieldValue = fieldMatch[2]; if (fieldValue.length === 0) { fieldValue = null; } else if (fieldValue.match(/^\d+$/) !== null) { // If it's a integer field, parse it as int fieldValue = parseInt(fieldValue); } // Don't parse float values since precision is lost var field = { name: fieldName, value: fieldValue }; fields.push(field); bytes = bytes.subarray(fieldLength); // Cut off the parsed field data } return new PaxHeader(fields); }; PaxHeader.prototype = { applyHeader: function(file) { // Apply fields to the file // If a field is of value null, it should be deleted from the file // https://www.mkssoftware.com/docs/man4/pax.4.asp this._fields.forEach(function(field) { var fieldName = field.name; var fieldValue = field.value; if (fieldName === "path") { // This overrides the name and prefix fields in the following header block. fieldName = "name"; if (file.prefix !== undefined) { delete file.prefix; } } else if (fieldName === "linkpath") { // This overrides the linkname field in the following header block. fieldName = "linkname"; } if (fieldValue === null) { delete file[fieldName]; } else { file[fieldName] = fieldValue; } }); } }; function TarFile() {} function UntarStream(arrayBuffer) { this._bufferView = new DataView(arrayBuffer); this._position = 0; } UntarStream.prototype = { readString: function(charCount) { //console.log("readString: position " + this.position() + ", " + charCount + " chars"); var charSize = 1; var byteCount = charCount * charSize; var charCodes = []; for (var i = 0; i < charCount; ++i) { var charCode = this._bufferView.getUint8( this.position() + i * charSize, true ); if (charCode !== 0) { charCodes.push(charCode); } else { break; } } this.seek(byteCount); return String.fromCharCode.apply(null, charCodes); }, readBuffer: function(byteCount) { var buf; if (typeof ArrayBuffer.prototype.slice === "function") { buf = this._bufferView.buffer.slice( this.position(), this.position() + byteCount ); } else { buf = new ArrayBuffer(byteCount); var target = new Uint8Array(buf); var src = new Uint8Array( this._bufferView.buffer, this.position(), byteCount ); target.set(src); } this.seek(byteCount); return buf; }, seek: function(byteCount) { this._position += byteCount; }, peekUint32: function() { return this._bufferView.getUint32(this.position(), true); }, position: function(newpos) { if (newpos === undefined) { return this._position; } else { this._position = newpos; } }, size: function() { return this._bufferView.byteLength; } }; function UntarFileStream(arrayBuffer) { this._stream = new UntarStream(arrayBuffer); this._globalPaxHeader = null; } UntarFileStream.prototype = { hasNext: function() { // A tar file ends with 4 zero bytes return ( this._stream.position() + 4 < this._stream.size() && this._stream.peekUint32() !== 0 ); }, next: function() { return this._readNextFile(); }, _readNextFile: function() { var stream = this._stream; var file = new TarFile(); var isHeaderFile = false; var paxHeader = null; var headerBeginPos = stream.position(); var dataBeginPos = headerBeginPos + 512; // Read header file.name = stream.readString(100); file.mode = stream.readString(8); file.uid = parseInt(stream.readString(8)); file.gid = parseInt(stream.readString(8)); file.size = parseInt(stream.readString(12), 8); file.mtime = parseInt(stream.readString(12), 8); file.checksum = parseInt(stream.readString(8)); file.type = stream.readString(1); file.linkname = stream.readString(100); file.ustarFormat = stream.readString(6); if (file.ustarFormat.indexOf("ustar") > -1) { file.version = stream.readString(2); file.uname = stream.readString(32); file.gname = stream.readString(32); file.devmajor = parseInt(stream.readString(8)); file.devminor = parseInt(stream.readString(8)); file.namePrefix = stream.readString(155); if (file.namePrefix.length > 0) { file.name = file.namePrefix + "/" + file.name; } } stream.position(dataBeginPos); // Derived from https://www.mkssoftware.com/docs/man4/pax.4.asp // and https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.3.0/com.ibm.zos.v2r3.bpxa500/pxarchfm.htm switch (file.type) { case "0": // Normal file is either "0" or "\0". case "": // In case of "\0", readString returns an empty string, that is "". file.buffer = stream.readBuffer(file.size); break; case "1": // Link to another file already archived // TODO Should we do anything with these? break; case "2": // Symbolic link // TODO Should we do anything with these? break; case "3": // Character special device (what does this mean??) break; case "4": // Block special device break; case "5": // Directory break; case "6": // FIFO special file break; case "7": // Reserved break; case "g": // Global PAX header isHeaderFile = true; this._globalPaxHeader = PaxHeader.parse(stream.readBuffer(file.size)); break; case "x": // PAX header isHeaderFile = true; paxHeader = PaxHeader.parse(stream.readBuffer(file.size)); break; default: // Unknown file type break; } if (file.buffer === undefined) { file.buffer = new ArrayBuffer(0); } var dataEndPos = dataBeginPos + file.size; // File data is padded to reach a 512 byte boundary; skip the padded bytes too. if (file.size % 512 !== 0) { dataEndPos += 512 - (file.size % 512); } stream.position(dataEndPos); if (isHeaderFile) { file = this._readNextFile(); } if (this._globalPaxHeader !== null) { this._globalPaxHeader.applyHeader(file); } if (paxHeader !== null) { paxHeader.applyHeader(file); } return file; } }; }