var fs = require("fs");
var zlib = require("zlib");
var fd_slicer = require("fd-slicer");
var crc32 = require("buffer-crc32");
var util = require("util");
var EventEmitter = require("events").EventEmitter;
var Transform = require("stream").Transform;
var PassThrough = require("stream").PassThrough;
var Writable = require("stream").Writable;
exports.open = open;
exports.fromFd = fromFd;
exports.fromBuffer = fromBuffer;
exports.fromRandomAccessReader = fromRandomAccessReader;
exports.dosDateTimeToDate = dosDateTimeToDate;
exports.validateFileName = validateFileName;
exports.ZipFile = ZipFile;
exports.Entry = Entry;
exports.RandomAccessReader = RandomAccessReader;
function open(path, options, callback) {
if (typeof options === "function") {
callback = options;
options = null;
}
if (options == null) options = {};
if (options.autoClose == null) options.autoClose = true;
if (options.lazyEntries == null) options.lazyEntries = false;
if (options.decodeStrings == null) options.decodeStrings = true;
if (options.validateEntrySizes == null) options.validateEntrySizes = true;
if (options.strictFileNames == null) options.strictFileNames = false;
if (callback == null) callback = defaultCallback;
fs.open(path, "r", function(err, fd) {
if (err) return callback(err);
fromFd(fd, options, function(err, zipfile) {
if (err) fs.close(fd, defaultCallback);
callback(err, zipfile);
});
});
}
function fromFd(fd, options, callback) {
if (typeof options === "function") {
callback = options;
options = null;
}
if (options == null) options = {};
if (options.autoClose == null) options.autoClose = false;
if (options.lazyEntries == null) options.lazyEntries = false;
if (options.decodeStrings == null) options.decodeStrings = true;
if (options.validateEntrySizes == null) options.validateEntrySizes = true;
if (options.strictFileNames == null) options.strictFileNames = false;
if (callback == null) callback = defaultCallback;
fs.fstat(fd, function(err, stats) {
if (err) return callback(err);
var reader = fd_slicer.createFromFd(fd, {autoClose: true});
fromRandomAccessReader(reader, stats.size, options, callback);
});
}
function fromBuffer(buffer, options, callback) {
if (typeof options === "function") {
callback = options;
options = null;
}
if (options == null) options = {};
options.autoClose = false;
if (options.lazyEntries == null) options.lazyEntries = false;
if (options.decodeStrings == null) options.decodeStrings = true;
if (options.validateEntrySizes == null) options.validateEntrySizes = true;
if (options.strictFileNames == null) options.strictFileNames = false;
// limit the max chunk size. see https://github.com/thejoshwolfe/yauzl/issues/87
var reader = fd_slicer.createFromBuffer(buffer, {maxChunkSize: 0x10000});
fromRandomAccessReader(reader, buffer.length, options, callback);
}
function fromRandomAccessReader(reader, totalSize, options, callback) {
if (typeof options === "function") {
callback = options;
options = null;
}
if (options == null) options = {};
if (options.autoClose == null) options.autoClose = true;
if (options.lazyEntries == null) options.lazyEntries = false;
if (options.decodeStrings == null) options.decodeStrings = true;
var decodeStrings = !!options.decodeStrings;
if (options.validateEntrySizes == null) options.validateEntrySizes = true;
if (options.strictFileNames == null) options.strictFileNames = false;
if (callback == null) callback = defaultCallback;
if (typeof totalSize !== "number") throw new Error("expected totalSize parameter to be a number");
if (totalSize > Number.MAX_SAFE_INTEGER) {
throw new Error("zip file too large. only file sizes up to 2^52 are supported due to JavaScript's Number type being an IEEE 754 double.");
}
// the matching unref() call is in zipfile.close()
reader.ref();
// eocdr means End of Central Directory Record.
// search backwards for the eocdr signature.
// the last field of the eocdr is a variable-length comment.
// the comment size is encoded in a 2-byte field in the eocdr, which we can't find without trudging backwards through the comment to find it.
// as a consequence of this design decision, it's possible to have ambiguous zip file metadata if a coherent eocdr was in the comment.
// we search backwards for a eocdr signature, and hope that whoever made the zip file was smart enough to forbid the eocdr signature in the comment.
var eocdrWithoutCommentSize = 22;
var maxCommentSize = 0xffff; // 2-byte size
var bufferSize = Math.min(eocdrWithoutCommentSize + maxCommentSize, totalSize);
var buffer = newBuffer(bufferSize);
var bufferReadStart = totalSize - buffer.length;
readAndAssertNoEof(reader, buffer, 0, bufferSize, bufferReadStart, function(err) {
if (err) return callback(err);
for (var i = bufferSize - eocdrWithoutCommentSize; i >= 0; i -= 1) {
if (buffer.readUInt32LE(i) !== 0x06054b50) continue;
// found eocdr
var eocdrBuffer = buffer.slice(i);
// 0 - End of central directory signature = 0x06054b50
// 4 - Number of this disk
var diskNumber = eocdrBuffer.readUInt16LE(4);
if (diskNumber !== 0) {
return callback(new Error("multi-disk zip files are not supported: found disk number: " + diskNumber));
}
// 6 - Disk where central directory starts
// 8 - Number of central directory records on this disk
// 10 - Total number of central directory records
var entryCount = eocdrBuffer.readUInt16LE(10);
// 12 - Size of central directory (bytes)
// 16 - Offset of start of central directory, relative to start of archive
var centralDirectoryOffset = eocdrBuffer.readUInt32LE(16);
// 20 - Comment length
var commentLength = eocdrBuffer.readUInt16LE(20);
var expectedCommentLength = eocdrBuffer.length - eocdrWithoutCommentSize;
if (commentLength !== expectedCommentLength) {
return callback(new Error("invalid comment length. expected: " + expectedCommentLength + ". found: " + commentLength));
}
// 22 - Comment
// the encoding is always cp437.
var comment = decodeStrings ? decodeBuffer(eocdrBuffer, 22, eocdrBuffer.length, false)
: eocdrBuffer.slice(22);
if (!(entryCount === 0xffff || centralDirectoryOffset === 0xffffffff)) {
return callback(null, new ZipFile(reader, centralDirectoryOffset, totalSize, entryCount, comment, options.autoClose, options.lazyEntries, decodeStrings, options.validateEntrySizes, options.strictFileNames));
}
// ZIP64 format
// ZIP64 Zip64 end of central directory locator
var zip64EocdlBuffer = newBuffer(20);
var zip64EocdlOffset = bufferReadStart + i - zip64EocdlBuffer.length;
readAndAssertNoEof(reader, zip64EocdlBuffer, 0, zip64EocdlBuffer.length, zip64EocdlOffset, function(err) {
if (err) return callback(err);
// 0 - zip64 end of central dir locator signature = 0x07064b50
if (zip64EocdlBuffer.readUInt32LE(0) !== 0x07064b50) {
return callback(new Error("invalid zip64 end of central directory locator signature"));
}
// 4 - number of the disk with the start of the zip64 end of central directory
// 8 - relative offset of the zip64 end of central directory record
var zip64EocdrOffset = readUInt64LE(zip64EocdlBuffer, 8);
// 16 - total number of disks
// ZIP64 end of central directory record
var zip64EocdrBuffer = newBuffer(56);
readAndAssertNoEof(reader, zip64EocdrBuffer, 0, zip64EocdrBuffer.length, zip64EocdrOffset, function(err) {
if (err) return callback(err);
// 0 - zip64 end of central dir signature 4 bytes (0x06064b50)
if (zip64EocdrBuffer.readUInt32LE(0) !== 0x06064b50) {
return callback(new Error("invalid zip64 end of central directory record signature"));
}
// 4 - size of zip64 end of central directory record 8 bytes
// 12 - version made by 2 bytes
// 14 - version needed to extract 2 bytes
// 16 - number of this disk 4 bytes
// 20 - number of the disk with the start of the central directory 4 bytes
// 24 - total number of entries in the central directory on this disk 8 bytes
// 32 - total number of entries in the central directory 8 bytes
entryCount = readUInt64LE(zip64EocdrBuffer, 32);
// 40 - size of the central directory 8 bytes
// 48 - offset of start of central directory with respect to the starting disk number 8 bytes
centralDirectoryOffset = readUInt64LE(zip64EocdrBuffer, 48);
// 56 - zip64 extensible data sector (variable size)
return callback(null, new ZipFile(reader, centralDirectoryOffset, totalSize, entryCount, comment, options.autoClose, options.lazyEntries, decodeStrings, options.validateEntrySizes, options.strictFileNames));
});
});
return;
}
callback(new Error("end of central directory record signature not found"));
});
}
util.inherits(ZipFile, EventEmitter);
function ZipFile(reader, centralDirectoryOffset, fileSize, entryCount, comment, autoClose, lazyEntries, decodeStrings, validateEntrySizes, strictFileNames) {
var self = this;
EventEmitter.call(self);
self.reader = reader;
// forward close events
self.reader.on("error", function(err) {
// error closing the fd
emitError(self, err);
});
self.reader.once("close", function() {
self.emit("close");
});
self.readEntryCursor = centralDirectoryOffset;
self.fileSize = fileSize;
self.entryCount = entryCount;
self.comment = comment;
self.entriesRead = 0;
self.autoClose = !!autoClose;
self.lazyEntries = !!lazyEntries;
self.decodeStrings = !!decodeStrings;
self.validateEntrySizes = !!validateEntrySizes;
self.strictFileNames = !!strictFileNames;
self.isOpen = true;
self.emittedError = false;
if (!self.lazyEntries) self._readEntry();
}
ZipFile.prototype.close = function() {
if (!this.isOpen) return;
this.isOpen = false;
this.reader.unref();
};
function emitErrorAndAutoClose(self, err) {
if (self.autoClose) self.close();
emitError(self, err);
}
function emitError(self, err) {
if (self.emittedError) return;
self.emittedError = true;
self.emit("error", err);
}
ZipFile.prototype.readEntry = function() {
if (!this.lazyEntries) throw new Error("readEntry() called without lazyEntries:true");
this._readEntry();
};
ZipFile.prototype._readEntry = function() {
var self = this;
if (self.entryCount === self.entriesRead) {
// done with metadata
setImmediate(function() {
if (self.autoClose) self.close();
if (self.emittedError) return;
self.emit("end");
});
return;
}
if (self.emittedError) return;
var buffer = newBuffer(46);
readAndAssertNoEof(self.reader, buffer, 0, buffer.length, self.readEntryCursor, function(err) {
if (err) return emitErrorAndAutoClose(self, err);
if (self.emittedError) return;
var entry = new Entry();
// 0 - Central directory file header signature
var signature = buffer.readUInt32LE(0);
if (signature !== 0x02014b50) return emitErrorAndAutoClose(self, new Error("invalid central directory file header signature: 0x" + signature.toString(16)));
// 4 - Version made by
entry.versionMadeBy = buffer.readUInt16LE(4);
// 6 - Version needed to extract (minimum)
entry.versionNeededToExtract = buffer.readUInt16LE(6);
// 8 - General purpose bit flag
entry.generalPurposeBitFlag = buffer.readUInt16LE(8);
// 10 - Compression method
entry.compressionMethod = buffer.readUInt16LE(10);
// 12 - File last modification time
entry.lastModFileTime = buffer.readUInt16LE(12);
// 14 - File last modification date
entry.lastModFileDate = buffer.readUInt16LE(14);
// 16 - CRC-32
entry.crc32 = buffer.readUInt32LE(16);
// 20 - Compressed size
entry.compressedSize = buffer.readUInt32LE(20);
// 24 - Uncompressed size
entry.uncompressedSize = buffer.readUInt32LE(24);
// 28 - File name length (n)
entry.fileNameLength = buffer.readUInt16LE(28);
// 30 - Extra field length (m)
entry.extraFieldLength = buffer.readUInt16LE(30);
// 32 - File comment length (k)
entry.fileCommentLength = buffer.readUInt16LE(32);
// 34 - Disk number where file starts
// 36 - Internal file attributes
entry.internalFileAttributes = buffer.readUInt16LE(36);
// 38 - External file attributes
entry.externalFileAttributes = buffer.readUInt32LE(38);
// 42 - Relative offset of local file header
entry.relativeOffsetOfLocalHeader = buffer.readUInt32LE(42);
if (entry.generalPurposeBitFlag & 0x40) return emitErrorAndAutoClose(self, new Error("strong encryption is not supported"));
self.readEntryCursor += 46;
buffer = newBuffer(entry.fileNameLength + entry.extraFieldLength + entry.fileCommentLength);
readAndAssertNoEof(self.reader, buffer, 0, buffer.length, self.readEntryCursor, function(err) {
if (err) return emitErrorAndAutoClose(self, err);
if (self.emittedError) return;
// 46 - File name
var isUtf8 = (entry.generalPurposeBitFlag & 0x800) !== 0;
entry.fileName = self.decodeStrings ? decodeBuffer(buffer, 0, entry.fileNameLength, isUtf8)
: buffer.slice(0, entry.fileNameLength);
// 46+n - Extra field
var fileCommentStart = entry.fileNameLength + entry.extraFieldLength;
var extraFieldBuffer = buffer.slice(entry.fileNameLength, fileCommentStart);
entry.extraFields = [];
var i = 0;
while (i < extraFieldBuffer.length - 3) {
var headerId = extraFieldBuffer.readUInt16LE(i + 0);
var dataSize = extraFieldBuffer.readUInt16LE(i + 2);
var dataStart = i + 4;
var dataEnd = dataStart + dataSize;
if (dataEnd > extraFieldBuffer.length) return emitErrorAndAutoClose(self, new Error("extra field length exceeds extra field buffer size"));
var dataBuffer = newBuffer(dataSize);
extraFieldBuffer.copy(dataBuffer, 0, dataStart, dataEnd);
entry.extraFields.push({
id: headerId,
data: dataBuffer,
});
i = dataEnd;
}
// 46+n+m - File comment
entry.fileComment = self.decodeStrings ? decodeBuffer(buffer, fileCommentStart, fileCommentStart + entry.fileCommentLength, isUtf8)
: buffer.slice(fileCommentStart, fileCommentStart + entry.fileCommentLength);
// compatibility hack for https://github.com/thejoshwolfe/yauzl/issues/47
entry.comment = entry.fileComment;
self.readEntryCursor += buffer.length;
self.entriesRead += 1;
if (entry.uncompressedSize === 0xffffffff ||
entry.compressedSize === 0xffffffff ||
entry.relativeOffsetOfLocalHeader === 0xffffffff) {
// ZIP64 format
// find the Zip64 Extended Information Extra Field
var zip64EiefBuffer = null;
for (var i = 0; i < entry.extraFields.length; i++) {
var extraField = entry.extraFields[i];
if (extraField.id === 0x0001) {
zip64EiefBuffer = extraField.data;
break;
}
}
if (zip64EiefBuffer == null) {
return emitErrorAndAutoClose(self, new Error("expected zip64 extended information extra field"));
}
var index = 0;
// 0 - Original Size 8 bytes
if (entry.uncompressedSize === 0xffffffff) {
if (index + 8 > zip64EiefBuffer.length) {
return emitErrorAndAutoClose(self, new Error("zip64 extended information extra field does not include uncompressed size"));
}
entry.uncompressedSize = readUInt64LE(zip64EiefBuffer, index);
index += 8;
}
// 8 - Compressed Size 8 bytes
if (entry.compressedSize === 0xffffffff) {
if (index + 8 > zip64EiefBuffer.length) {
return emitErrorAndAutoClose(self, new Error("zip64 extended information extra field does not include compressed size"));
}
entry.compressedSize = readUInt64LE(zip64EiefBuffer, index);
index += 8;
}
// 16 - Relative Header Offset 8 bytes
if (entry.relativeOffsetOfLocalHeader === 0xffffffff) {
if (index + 8 > zip64EiefBuffer.length) {
return emitErrorAndAutoClose(self, new Error("zip64 extended information extra field does not include relative header offset"));
}
entry.relativeOffsetOfLocalHeader = readUInt64LE(zip64EiefBuffer, index);
index += 8;
}
// 24 - Disk Start Number 4 bytes
}
// check for Info-ZIP Unicode Path Extra Field (0x7075)
// see https://github.com/thejoshwolfe/yauzl/issues/33
if (self.decodeStrings) {
for (var i = 0; i < entry.extraFields.length; i++) {
var extraField = entry.extraFields[i];
if (extraField.id === 0x7075) {
if (extraField.data.length < 6) {
// too short to be meaningful
continue;
}
// Version 1 byte version of this extra field, currently 1
if (extraField.data.readUInt8(0) !== 1) {
// > Changes may not be backward compatible so this extra
// > field should not be used if the version is not recognized.
continue;
}
// NameCRC32 4 bytes File Name Field CRC32 Checksum
var oldNameCrc32 = extraField.data.readUInt32LE(1);
if (crc32.unsigned(buffer.slice(0, entry.fileNameLength)) !== oldNameCrc32) {
// > If the CRC check fails, this UTF-8 Path Extra Field should be
// > ignored and the File Name field in the header should be used instead.
continue;
}
// UnicodeName Variable UTF-8 version of the entry File Name
entry.fileName = decodeBuffer(extraField.data, 5, extraField.data.length, true);
break;
}
}
}
// validate file size
if (self.validateEntrySizes && entry.compressionMethod === 0) {
var expectedCompressedSize = entry.uncompressedSize;
if (entry.isEncrypted()) {
// traditional encryption prefixes the file data with a header
expectedCompressedSize += 12;
}
if (entry.compressedSize !== expectedCompressedSize) {
var msg = "compressed/uncompressed size mismatch for stored file: " + entry.compressedSize + " != " + entry.uncompressedSize;
return emitErrorAndAutoClose(self, new Error(msg));
}
}
if (self.decodeStrings) {
if (!self.strictFileNames) {
// allow backslash
entry.fileName = entry.fileName.replace(/\\/g, "/");
}
var errorMessage = validateFileName(entry.fileName, self.validateFileNameOptions);
if (errorMessage != null) return emitErrorAndAutoClose(self, new Error(errorMessage));
}
self.emit("entry", entry);
if (!self.lazyEntries) self._readEntry();
});
});
};
ZipFile.prototype.openReadStream = function(entry, options, callback) {
var self = this;
// parameter validation
var relativeStart = 0;
var relativeEnd = entry.compressedSize;
if (callback == null) {
callback = options;
options = {};
} else {
// validate options that the caller has no excuse to get wrong
if (options.decrypt != null) {
if (!entry.isEncrypted()) {
throw new Error("options.decrypt can only be specified for encrypted entries");
}
if (options.decrypt !== false) throw new Error("invalid options.decrypt value: " + options.decrypt);
if (entry.isCompressed()) {
if (options.decompress !== false) throw new Error("entry is encrypted and compressed, and options.decompress !== false");
}
}
if (options.decompress != null) {
if (!entry.isCompressed()) {
throw new Error("options.decompress can only be specified for compressed entries");
}
if (!(options.decompress === false || options.decompress === true)) {
throw new Error("invalid options.decompress value: " + options.decompress);
}
}
if (options.start != null || options.end != null) {
if (entry.isCompressed() && options.decompress !== false) {
throw new Error("start/end range not allowed for compressed entry without options.decompress === false");
}
if (entry.isEncrypted() && options.decrypt !== false) {
throw new Error("start/end range not allowed for encrypted entry without options.decrypt === false");
}
}
if (options.start != null) {
relativeStart = options.start;
if (relativeStart < 0) throw new Error("options.start < 0");
if (relativeStart > entry.compressedSize) throw new Error("options.start > entry.compressedSize");
}
if (options.end != null) {
relativeEnd = options.end;
if (relativeEnd < 0) throw new Error("options.end < 0");
if (relativeEnd > entry.compressedSize) throw new Error("options.end > entry.compressedSize");
if (relativeEnd < relativeStart) throw new Error("options.end < options.start");
}
}
// any further errors can either be caused by the zipfile,
// or were introduced in a minor version of yauzl,
// so should be passed to the client rather than thrown.
if (!self.isOpen) return callback(new Error("closed"));
if (entry.isEncrypted()) {
if (options.decrypt !== false) return callback(new Error("entry is encrypted, and options.decrypt !== false"));
}
// make sure we don't lose the fd before we open the actual read stream
self.reader.ref();
var buffer = newBuffer(30);
readAndAssertNoEof(self.reader, buffer, 0, buffer.length, entry.relativeOffsetOfLocalHeader, function(err) {
try {
if (err) return callback(err);
// 0 - Local file header signature = 0x04034b50
var signature = buffer.readUInt32LE(0);
if (signature !== 0x04034b50) {
return callback(new Error("invalid local file header signature: 0x" + signature.toString(16)));
}
// all this should be redundant
// 4 - Version needed to extract (minimum)
// 6 - General purpose bit flag
// 8 - Compression method
// 10 - File last modification time
// 12 - File last modification date
// 14 - CRC-32
// 18 - Compressed size
// 22 - Uncompressed size
// 26 - File name length (n)
var fileNameLength = buffer.readUInt16LE(26);
// 28 - Extra field length (m)
var extraFieldLength = buffer.readUInt16LE(28);
// 30 - File name
// 30+n - Extra field
var localFileHeaderEnd = entry.relativeOffsetOfLocalHeader + buffer.length + fileNameLength + extraFieldLength;
var decompress;
if (entry.compressionMethod === 0) {
// 0 - The file is stored (no compression)
decompress = false;
} else if (entry.compressionMethod === 8) {
// 8 - The file is Deflated
decompress = options.decompress != null ? options.decompress : true;
} else {
return callback(new Error("unsupported compression method: " + entry.compressionMethod));
}
var fileDataStart = localFileHeaderEnd;
var fileDataEnd = fileDataStart + entry.compressedSize;
if (entry.compressedSize !== 0) {
// bounds check now, because the read streams will probably not complain loud enough.
// since we're dealing with an unsigned offset plus an unsigned size,
// we only have 1 thing to check for.
if (fileDataEnd > self.fileSize) {
return callback(new Error("file data overflows file bounds: " +
fileDataStart + " + " + entry.compressedSize + " > " + self.fileSize));
}
}
var readStream = self.reader.createReadStream({
start: fileDataStart + relativeStart,
end: fileDataStart + relativeEnd,
});
var endpointStream = readStream;
if (decompress) {
var destroyed = false;
var inflateFilter = zlib.createInflateRaw();
readStream.on("error", function(err) {
// setImmediate here because errors can be emitted during the first call to pipe()
setImmediate(function() {
if (!destroyed) inflateFilter.emit("error", err);
});
});
readStream.pipe(inflateFilter);
if (self.validateEntrySizes) {
endpointStream = new AssertByteCountStream(entry.uncompressedSize);
inflateFilter.on("error", function(err) {
// forward zlib errors to the client-visible stream
setImmediate(function() {
if (!destroyed) endpointStream.emit("error", err);
});
});
inflateFilter.pipe(endpointStream);
} else {
// the zlib filter is the client-visible stream
endpointStream = inflateFilter;
}
// this is part of yauzl's API, so implement this function on the client-visible stream
endpointStream.destroy = function() {
destroyed = true;
if (inflateFilter !== endpointStream) inflateFilter.unpipe(endpointStream);
readStream.unpipe(inflateFilter);
// TODO: the inflateFilter may cause a memory leak. see Issue #27.
readStream.destroy();
};
}
callback(null, endpointStream);
} finally {
self.reader.unref();
}
});
};
function Entry() {
}
Entry.prototype.getLastModDate = function() {
return dosDateTimeToDate(this.lastModFileDate, this.lastModFileTime);
};
Entry.prototype.isEncrypted = function() {
return (this.generalPurposeBitFlag & 0x1) !== 0;
};
Entry.prototype.isCompressed = function() {
return this.compressionMethod === 8;
};
function dosDateTimeToDate(date, time) {
var day = date & 0x1f; // 1-31
var month = (date >> 5 & 0xf) - 1; // 1-12, 0-11
var year = (date >> 9 & 0x7f) + 1980; // 0-128, 1980-2108
var millisecond = 0;
var second = (time & 0x1f) * 2; // 0-29, 0-58 (even numbers)
var minute = time >> 5 & 0x3f; // 0-59
var hour = time >> 11 & 0x1f; // 0-23
return new Date(year, month, day, hour, minute, second, millisecond);
}
function validateFileName(fileName) {
if (fileName.indexOf("\\") !== -1) {
return "invalid characters in fileName: " + fileName;
}
if (/^[a-zA-Z]:/.test(fileName) || /^\//.test(fileName)) {
return "absolute path: " + fileName;
}
if (fileName.split("/").indexOf("..") !== -1) {
return "invalid relative path: " + fileName;
}
// all good
return null;
}
function readAndAssertNoEof(reader, buffer, offset, length, position, callback) {
if (length === 0) {
// fs.read will throw an out-of-bounds error if you try to read 0 bytes from a 0 byte file
return setImmediate(function() { callback(null, newBuffer(0)); });
}
reader.read(buffer, offset, length, position, function(err, bytesRead) {
if (err) return callback(err);
if (bytesRead < length) {
return callback(new Error("unexpected EOF"));
}
callback();
});
}
util.inherits(AssertByteCountStream, Transform);
function AssertByteCountStream(byteCount) {
Transform.call(this);
this.actualByteCount = 0;
this.expectedByteCount = byteCount;
}
AssertByteCountStream.prototype._transform = function(chunk, encoding, cb) {
this.actualByteCount += chunk.length;
if (this.actualByteCount > this.expectedByteCount) {
var msg = "too many bytes in the stream. expected " + this.expectedByteCount + ". got at least " + this.actualByteCount;
return cb(new Error(msg));
}
cb(null, chunk);
};
AssertByteCountStream.prototype._flush = function(cb) {
if (this.actualByteCount < this.expectedByteCount) {
var msg = "not enough bytes in the stream. expected " + this.expectedByteCount + ". got only " + this.actualByteCount;
return cb(new Error(msg));
}
cb();
};
util.inherits(RandomAccessReader, EventEmitter);
function RandomAccessReader() {
EventEmitter.call(this);
this.refCount = 0;
}
RandomAccessReader.prototype.ref = function() {
this.refCount += 1;
};
RandomAccessReader.prototype.unref = function() {
var self = this;
self.refCount -= 1;
if (self.refCount > 0) return;
if (self.refCount < 0) throw new Error("invalid unref");
self.close(onCloseDone);
function onCloseDone(err) {
if (err) return self.emit('error', err);
self.emit('close');
}
};
RandomAccessReader.prototype.createReadStream = function(options) {
var start = options.start;
var end = options.end;
if (start === end) {
var emptyStream = new PassThrough();
setImmediate(function() {
emptyStream.end();
});
return emptyStream;
}
var stream = this._readStreamForRange(start, end);
var destroyed = false;
var refUnrefFilter = new RefUnrefFilter(this);
stream.on("error", function(err) {
setImmediate(function() {
if (!destroyed) refUnrefFilter.emit("error", err);
});
});
refUnrefFilter.destroy = function() {
stream.unpipe(refUnrefFilter);
refUnrefFilter.unref();
stream.destroy();
};
var byteCounter = new AssertByteCountStream(end - start);
refUnrefFilter.on("error", function(err) {
setImmediate(function() {
if (!destroyed) byteCounter.emit("error", err);
});
});
byteCounter.destroy = function() {
destroyed = true;
refUnrefFilter.unpipe(byteCounter);
refUnrefFilter.destroy();
};
return stream.pipe(refUnrefFilter).pipe(byteCounter);
};
RandomAccessReader.prototype._readStreamForRange = function(start, end) {
throw new Error("not implemented");
};
RandomAccessReader.prototype.read = function(buffer, offset, length, position, callback) {
var readStream = this.createReadStream({start: position, end: position + length});
var writeStream = new Writable();
var written = 0;
writeStream._write = function(chunk, encoding, cb) {
chunk.copy(buffer, offset + written, 0, chunk.length);
written += chunk.length;
cb();
};
writeStream.on("finish", callback);
readStream.on("error", function(error) {
callback(error);
});
readStream.pipe(writeStream);
};
RandomAccessReader.prototype.close = function(callback) {
setImmediate(callback);
};
util.inherits(RefUnrefFilter, PassThrough);
function RefUnrefFilter(context) {
PassThrough.call(this);
this.context = context;
this.context.ref();
this.unreffedYet = false;
}
RefUnrefFilter.prototype._flush = function(cb) {
this.unref();
cb();
};
RefUnrefFilter.prototype.unref = function(cb) {
if (this.unreffedYet) return;
this.unreffedYet = true;
this.context.unref();
};
var cp437 = '\u0000☺☻♥♦♣♠•◘○◙♂♀♪♫☼►◄↕‼¶§▬↨↑↓→←∟↔▲▼ !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~⌂ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ¢£¥₧ƒáíóúñѪº¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐└┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ ';
function decodeBuffer(buffer, start, end, isUtf8) {
if (isUtf8) {
return buffer.toString("utf8", start, end);
} else {
var result = "";
for (var i = start; i < end; i++) {
result += cp437[buffer[i]];
}
return result;
}
}
function readUInt64LE(buffer, offset) {
// there is no native function for this, because we can't actually store 64-bit integers precisely.
// after 53 bits, JavaScript's Number type (IEEE 754 double) can't store individual integers anymore.
// but since 53 bits is a whole lot more than 32 bits, we do our best anyway.
var lower32 = buffer.readUInt32LE(offset);
var upper32 = buffer.readUInt32LE(offset + 4);
// we can't use bitshifting here, because JavaScript bitshifting only works on 32-bit integers.
return upper32 * 0x100000000 + lower32;
// as long as we're bounds checking the result of this function against the total file size,
// we'll catch any overflow errors, because we already made sure the total file size was within reason.
}
// Node 10 deprecated new Buffer().
var newBuffer;
if (typeof Buffer.allocUnsafe === "function") {
newBuffer = function(len) {
return Buffer.allocUnsafe(len);
};
} else {
newBuffer = function(len) {
return new Buffer(len);
};
}
function defaultCallback(err) {
if (err) throw err;
}
