-var assert
-
exports.Buffer = Buffer
exports.SlowBuffer = Buffer
exports.INSPECT_MAX_BYTES = 50
Buffer.poolSize = 8192
-// TODO: throw the correct exception type on errors (look at node source)
+var assert
+var browserSupport
+/**
+ * Class: Buffer
+ * =============
+ *
+ * The Buffer constructor returns instances of `Uint8Array` that are augmented
+ * with function properties for all the node `Buffer` API functions. We use
+ * `Uint8Array` so that square bracket notation works as expected -- it returns
+ * a single octet.
+ *
+ * By augmenting the instances, we can avoid modifying the `Uint8Array`
+ * prototype.
+ *
+ * Firefox is a special case because it doesn't allow augmenting "native" object
+ * instances. See `ProxyBuffer` below for more details.
+ */
function Buffer (subject, encoding) {
if (!assert) assert = require('assert')
}
Buffer.isBuffer = function isBuffer (b) {
- return b instanceof Uint8Array && b._isBuffer
+ return b && b._isBuffer
}
Buffer.byteLength = function (str, encoding) {
}
function BufferToString (encoding, start, end) {
+ var self = (this instanceof ProxyBuffer)
+ ? this._proxy
+ : this
+
encoding = String(encoding || 'utf8').toLowerCase()
start = Number(start) || 0
end = (end !== undefined)
? Number(end)
- : end = this.length
+ : end = self.length
// Fastpath empty strings
if (end === start)
switch (encoding) {
case 'hex':
- return _hexSlice(this, start, end)
+ return _hexSlice(self, start, end)
case 'utf8':
case 'utf-8':
- return _utf8Slice(this, start, end)
+ return _utf8Slice(self, start, end)
case 'ascii':
- return _asciiSlice(this, start, end)
+ return _asciiSlice(self, start, end)
case 'binary':
- return _binarySlice(this, start, end)
+ return _binarySlice(self, start, end)
case 'base64':
- return _base64Slice(this, start, end)
+ return _base64Slice(self, start, end)
default:
throw new Error('Unknown encoding')
return str.replace(/^\s+|\s+$/g, '')
}
-function augment (arr) {
- // Augment the Uint8Array *instance* (not the class!) with Buffer methods
- arr.write = BufferWrite
- arr.toString = BufferToString
- arr.toLocaleString = BufferToString
- arr.toJSON = BufferToJSON
- arr.copy = BufferCopy
- arr.slice = BufferSlice
- arr.readUInt8 = BufferReadUInt8
- arr.readUInt16LE = BufferReadUInt16LE
- arr.readUInt16BE = BufferReadUInt16BE
- arr.readUInt32LE = BufferReadUInt32LE
- arr.readUInt32BE = BufferReadUInt32BE
- arr.readInt8 = BufferReadInt8
- arr.readInt16LE = BufferReadInt16LE
- arr.readInt16BE = BufferReadInt16BE
- arr.readInt32LE = BufferReadInt32LE
- arr.readInt32BE = BufferReadInt32BE
- arr.readFloatLE = BufferReadFloatLE
- arr.readFloatBE = BufferReadFloatBE
- arr.readDoubleLE = BufferReadDoubleLE
- arr.readDoubleBE = BufferReadDoubleBE
- arr.writeUInt8 = BufferWriteUInt8
- arr.writeUInt16LE = BufferWriteUInt16LE
- arr.writeUInt16BE = BufferWriteUInt16BE
- arr.writeUInt32LE = BufferWriteUInt32LE
- arr.writeUInt32BE = BufferWriteUInt32BE
- arr.writeInt8 = BufferWriteInt8
- arr.writeInt16LE = BufferWriteInt16LE
- arr.writeInt16BE = BufferWriteInt16BE
- arr.writeInt32LE = BufferWriteInt32LE
- arr.writeInt32BE = BufferWriteInt32BE
- arr.writeFloatLE = BufferWriteFloatLE
- arr.writeFloatBE = BufferWriteFloatBE
- arr.writeDoubleLE = BufferWriteDoubleLE
- arr.writeDoubleBE = BufferWriteDoubleBE
- arr.fill = BufferFill
- arr.inspect = BufferInspect
- arr.toArrayBuffer = BufferToArrayBuffer
-
- arr._isBuffer = true
+/**
+ * Check to see if the browser supports augmenting a `Uint8Array` instance.
+ * @return {boolean}
+ */
+function _browserSupport () {
+ var arr = new Uint8Array(0)
+ arr.foo = function () { return 42 }
+
+ try {
+ return (42 === arr.foo())
+ } catch (e) {
+ return false
+ }
+}
+
+/**
+ * Class: ProxyBuffer
+ * ==================
+ *
+ * Only used in Firefox, since Firefox does not allow augmenting "native"
+ * objects (like Uint8Array instances) with new properties for some unknown
+ * (probably silly) reason. So we'll use an ES6 Proxy (supported since
+ * Firefox 18) to wrap the Uint8Array instance without actually adding any
+ * properties to it.
+ *
+ * Instances of this "fake" Buffer class are the "target" of the
+ * ES6 Proxy (see `augment` function).
+ *
+ * We couldn't just use the `Uint8Array` as the target of the `Proxy` because
+ * Proxies have an important limitation on trapping the `toString` method.
+ * `Object.prototype.toString.call(proxy)` gets called whenever something is
+ * implicitly cast to a String. Unfortunately, with a `Proxy` this
+ * unconditionally returns `Object.prototype.toString.call(target)` which would
+ * always return "[object Uint8Array]" if we used the `Uint8Array` instance as
+ * the target. And, remember, in Firefox we cannot redefine the `Uint8Array`
+ * instance's `toString` method.
+ *
+ * So, we use this `ProxyBuffer` class as the proxy's "target". Since this class
+ * has its own custom `toString` method, it will get called whenever `toString`
+ * gets called, implicitly or explicitly, on the `Proxy` instance.
+ *
+ * We also have to define the Uint8Array methods `subarray` and `set` on
+ * `ProxyBuffer` because if we didn't then `proxy.subarray(0)` would have its
+ * `this` set to `proxy` (a `Proxy` instance) which throws an exception in
+ * Firefox which expects it to be a `TypedArray` instance.
+ */
+function ProxyBuffer (arr) {
+ this._arr = arr
if (arr.byteLength !== 0)
- arr._dataview = new DataView(arr.buffer, arr.byteOffset, arr.byteLength)
+ this._dataview = new DataView(arr.buffer, arr.byteOffset, arr.byteLength)
+}
+
+ProxyBuffer.prototype.write = BufferWrite
+ProxyBuffer.prototype.toString = BufferToString
+ProxyBuffer.prototype.toLocaleString = BufferToString
+ProxyBuffer.prototype.toJSON = BufferToJSON
+ProxyBuffer.prototype.copy = BufferCopy
+ProxyBuffer.prototype.slice = BufferSlice
+ProxyBuffer.prototype.readUInt8 = BufferReadUInt8
+ProxyBuffer.prototype.readUInt16LE = BufferReadUInt16LE
+ProxyBuffer.prototype.readUInt16BE = BufferReadUInt16BE
+ProxyBuffer.prototype.readUInt32LE = BufferReadUInt32LE
+ProxyBuffer.prototype.readUInt32BE = BufferReadUInt32BE
+ProxyBuffer.prototype.readInt8 = BufferReadInt8
+ProxyBuffer.prototype.readInt16LE = BufferReadInt16LE
+ProxyBuffer.prototype.readInt16BE = BufferReadInt16BE
+ProxyBuffer.prototype.readInt32LE = BufferReadInt32LE
+ProxyBuffer.prototype.readInt32BE = BufferReadInt32BE
+ProxyBuffer.prototype.readFloatLE = BufferReadFloatLE
+ProxyBuffer.prototype.readFloatBE = BufferReadFloatBE
+ProxyBuffer.prototype.readDoubleLE = BufferReadDoubleLE
+ProxyBuffer.prototype.readDoubleBE = BufferReadDoubleBE
+ProxyBuffer.prototype.writeUInt8 = BufferWriteUInt8
+ProxyBuffer.prototype.writeUInt16LE = BufferWriteUInt16LE
+ProxyBuffer.prototype.writeUInt16BE = BufferWriteUInt16BE
+ProxyBuffer.prototype.writeUInt32LE = BufferWriteUInt32LE
+ProxyBuffer.prototype.writeUInt32BE = BufferWriteUInt32BE
+ProxyBuffer.prototype.writeInt8 = BufferWriteInt8
+ProxyBuffer.prototype.writeInt16LE = BufferWriteInt16LE
+ProxyBuffer.prototype.writeInt16BE = BufferWriteInt16BE
+ProxyBuffer.prototype.writeInt32LE = BufferWriteInt32LE
+ProxyBuffer.prototype.writeInt32BE = BufferWriteInt32BE
+ProxyBuffer.prototype.writeFloatLE = BufferWriteFloatLE
+ProxyBuffer.prototype.writeFloatBE = BufferWriteFloatBE
+ProxyBuffer.prototype.writeDoubleLE = BufferWriteDoubleLE
+ProxyBuffer.prototype.writeDoubleBE = BufferWriteDoubleBE
+ProxyBuffer.prototype.fill = BufferFill
+ProxyBuffer.prototype.inspect = BufferInspect
+ProxyBuffer.prototype.toArrayBuffer = BufferToArrayBuffer
+ProxyBuffer.prototype._isBuffer = true
+ProxyBuffer.prototype.subarray = function () {
+ return this._arr.subarray.apply(this._arr, arguments)
+}
+ProxyBuffer.prototype.set = function () {
+ return this._arr.set.apply(this._arr, arguments)
+}
+
+var ProxyHandler = {
+ get: function (target, name) {
+ if (name in target) return target[name]
+ else return target._arr[name]
+ },
+ set: function (target, name, value) {
+ target._arr[name] = value
+ }
+}
+
+function augment (arr) {
+ if (browserSupport === undefined) {
+ browserSupport = _browserSupport()
+ }
- return arr
+ if (browserSupport) {
+ // Augment the Uint8Array *instance* (not the class!) with Buffer methods
+ arr.write = BufferWrite
+ arr.toString = BufferToString
+ arr.toLocaleString = BufferToString
+ arr.toJSON = BufferToJSON
+ arr.copy = BufferCopy
+ arr.slice = BufferSlice
+ arr.readUInt8 = BufferReadUInt8
+ arr.readUInt16LE = BufferReadUInt16LE
+ arr.readUInt16BE = BufferReadUInt16BE
+ arr.readUInt32LE = BufferReadUInt32LE
+ arr.readUInt32BE = BufferReadUInt32BE
+ arr.readInt8 = BufferReadInt8
+ arr.readInt16LE = BufferReadInt16LE
+ arr.readInt16BE = BufferReadInt16BE
+ arr.readInt32LE = BufferReadInt32LE
+ arr.readInt32BE = BufferReadInt32BE
+ arr.readFloatLE = BufferReadFloatLE
+ arr.readFloatBE = BufferReadFloatBE
+ arr.readDoubleLE = BufferReadDoubleLE
+ arr.readDoubleBE = BufferReadDoubleBE
+ arr.writeUInt8 = BufferWriteUInt8
+ arr.writeUInt16LE = BufferWriteUInt16LE
+ arr.writeUInt16BE = BufferWriteUInt16BE
+ arr.writeUInt32LE = BufferWriteUInt32LE
+ arr.writeUInt32BE = BufferWriteUInt32BE
+ arr.writeInt8 = BufferWriteInt8
+ arr.writeInt16LE = BufferWriteInt16LE
+ arr.writeInt16BE = BufferWriteInt16BE
+ arr.writeInt32LE = BufferWriteInt32LE
+ arr.writeInt32BE = BufferWriteInt32BE
+ arr.writeFloatLE = BufferWriteFloatLE
+ arr.writeFloatBE = BufferWriteFloatBE
+ arr.writeDoubleLE = BufferWriteDoubleLE
+ arr.writeDoubleBE = BufferWriteDoubleBE
+ arr.fill = BufferFill
+ arr.inspect = BufferInspect
+ arr.toArrayBuffer = BufferToArrayBuffer
+ arr._isBuffer = true
+
+ if (arr.byteLength !== 0)
+ arr._dataview = new DataView(arr.buffer, arr.byteOffset, arr.byteLength)
+
+ return arr
+
+ } else {
+ // This is a browser that doesn't support augmenting the `Uint8Array`
+ // instance (*ahem* Firefox) so use an ES6 `Proxy`.
+ var proxyBuffer = new ProxyBuffer(arr)
+ var proxy = new Proxy(proxyBuffer, ProxyHandler)
+ proxyBuffer._proxy = proxy
+ return proxy
+ }
}
// slice(start, end)
projects / buffer.git / commitdiff