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