221 lines
5 KiB
JavaScript
221 lines
5 KiB
JavaScript
var DuplexStream = require('readable-stream/duplex')
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, util = require('util')
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function BufferList (callback) {
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if (!(this instanceof BufferList))
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return new BufferList(callback)
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this._bufs = []
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this.length = 0
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if (typeof callback == 'function') {
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this._callback = callback
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var piper = function (err) {
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if (this._callback) {
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this._callback(err)
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this._callback = null
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}
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}.bind(this)
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this.on('pipe', function (src) {
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src.on('error', piper)
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})
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this.on('unpipe', function (src) {
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src.removeListener('error', piper)
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})
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}
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else if (Buffer.isBuffer(callback))
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this.append(callback)
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else if (Array.isArray(callback)) {
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callback.forEach(function (b) {
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Buffer.isBuffer(b) && this.append(b)
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}.bind(this))
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}
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DuplexStream.call(this)
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}
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util.inherits(BufferList, DuplexStream)
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BufferList.prototype._offset = function (offset) {
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var tot = 0, i = 0, _t
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for (; i < this._bufs.length; i++) {
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_t = tot + this._bufs[i].length
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if (offset < _t)
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return [ i, offset - tot ]
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tot = _t
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}
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}
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BufferList.prototype.append = function (buf) {
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var isBuffer = Buffer.isBuffer(buf) ||
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buf instanceof BufferList
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// coerce number arguments to strings, since Buffer(number) does
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// uninitialized memory allocation
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if (typeof buf == 'number')
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buf = buf.toString()
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this._bufs.push(isBuffer ? buf : new Buffer(buf))
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this.length += buf.length
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return this
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}
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BufferList.prototype._write = function (buf, encoding, callback) {
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this.append(buf)
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if (callback)
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callback()
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}
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BufferList.prototype._read = function (size) {
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if (!this.length)
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return this.push(null)
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size = Math.min(size, this.length)
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this.push(this.slice(0, size))
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this.consume(size)
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}
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BufferList.prototype.end = function (chunk) {
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DuplexStream.prototype.end.call(this, chunk)
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if (this._callback) {
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this._callback(null, this.slice())
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this._callback = null
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}
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}
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BufferList.prototype.get = function (index) {
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return this.slice(index, index + 1)[0]
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}
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BufferList.prototype.slice = function (start, end) {
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return this.copy(null, 0, start, end)
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}
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BufferList.prototype.copy = function (dst, dstStart, srcStart, srcEnd) {
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if (typeof srcStart != 'number' || srcStart < 0)
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srcStart = 0
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if (typeof srcEnd != 'number' || srcEnd > this.length)
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srcEnd = this.length
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if (srcStart >= this.length)
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return dst || new Buffer(0)
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if (srcEnd <= 0)
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return dst || new Buffer(0)
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var copy = !!dst
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, off = this._offset(srcStart)
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, len = srcEnd - srcStart
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, bytes = len
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, bufoff = (copy && dstStart) || 0
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, start = off[1]
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, l
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, i
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// copy/slice everything
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if (srcStart === 0 && srcEnd == this.length) {
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if (!copy) // slice, just return a full concat
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return Buffer.concat(this._bufs)
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// copy, need to copy individual buffers
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for (i = 0; i < this._bufs.length; i++) {
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this._bufs[i].copy(dst, bufoff)
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bufoff += this._bufs[i].length
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}
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return dst
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}
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// easy, cheap case where it's a subset of one of the buffers
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if (bytes <= this._bufs[off[0]].length - start) {
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return copy
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? this._bufs[off[0]].copy(dst, dstStart, start, start + bytes)
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: this._bufs[off[0]].slice(start, start + bytes)
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}
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if (!copy) // a slice, we need something to copy in to
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dst = new Buffer(len)
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for (i = off[0]; i < this._bufs.length; i++) {
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l = this._bufs[i].length - start
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if (bytes > l) {
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this._bufs[i].copy(dst, bufoff, start)
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} else {
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this._bufs[i].copy(dst, bufoff, start, start + bytes)
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break
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}
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bufoff += l
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bytes -= l
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if (start)
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start = 0
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}
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return dst
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}
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BufferList.prototype.toString = function (encoding, start, end) {
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return this.slice(start, end).toString(encoding)
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}
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BufferList.prototype.consume = function (bytes) {
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while (this._bufs.length) {
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if (bytes > this._bufs[0].length) {
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bytes -= this._bufs[0].length
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this.length -= this._bufs[0].length
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this._bufs.shift()
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} else {
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this._bufs[0] = this._bufs[0].slice(bytes)
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this.length -= bytes
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break
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}
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}
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return this
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}
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BufferList.prototype.duplicate = function () {
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var i = 0
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, copy = new BufferList()
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for (; i < this._bufs.length; i++)
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copy.append(this._bufs[i])
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return copy
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}
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BufferList.prototype.destroy = function () {
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this._bufs.length = 0;
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this.length = 0;
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this.push(null);
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}
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;(function () {
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var methods = {
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'readDoubleBE' : 8
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, 'readDoubleLE' : 8
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, 'readFloatBE' : 4
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, 'readFloatLE' : 4
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, 'readInt32BE' : 4
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, 'readInt32LE' : 4
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, 'readUInt32BE' : 4
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, 'readUInt32LE' : 4
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, 'readInt16BE' : 2
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, 'readInt16LE' : 2
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, 'readUInt16BE' : 2
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, 'readUInt16LE' : 2
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, 'readInt8' : 1
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, 'readUInt8' : 1
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}
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for (var m in methods) {
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(function (m) {
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BufferList.prototype[m] = function (offset) {
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return this.slice(offset, offset + methods[m])[m](0)
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}
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}(m))
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}
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}())
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module.exports = BufferList
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