v5: Remove Object implementation

diff --git a/index.js b/index.js
index b55b9aa43c054e45211347ba5eddc0daed845e72..4c5e2514ae6e7a369ed8b63460d5a7fd6b9905c8 100644 (file)
--- a/index.js
+++ b/index.js
@@ -15,18 +15,20 @@ exports.Buffer = Buffer
 exports.SlowBuffer = SlowBuffer
 exports.INSPECT_MAX_BYTES = 50
 
+var K_MAX_LENGTH = 0x7fffffff
+exports.kMaxLength = K_MAX_LENGTH
+
 /**
- * If `Buffer.TYPED_ARRAY_SUPPORT`:
+ * If `TYPED_ARRAY_SUPPORT`:
  *   === true    Use Uint8Array implementation (fastest)
- *   === false   Use Object implementation (most compatible, even IE6)
+ *   === false   Print warning and recommend using `buffer` v4.x which has an Object
+ *               implementation (most compatible, even IE6)
  *
  * Browsers that support typed arrays are IE 10+, Firefox 4+, Chrome 7+, Safari 5.1+,
  * Opera 11.6+, iOS 4.2+.
  *
- * Due to various browser bugs, sometimes the Object implementation will be used even
- * when the browser supports typed arrays.
- *
- * Note:
+ * Sometimes we report that the browser does not support typed arrays, if there
+ * exist extreme bugs in the implemetation. For example:
  *
  *   - Firefox 4-29 lacks support for adding new properties to `Uint8Array` instances,
  *     See: https://bugzilla.mozilla.org/show_bug.cgi?id=695438.
@@ -35,18 +37,14 @@ exports.INSPECT_MAX_BYTES = 50
  *
  *   - IE10 has a broken `TypedArray.prototype.subarray` function which returns arrays of
  *     incorrect length in some situations.
-
- * We detect these buggy browsers and set `Buffer.TYPED_ARRAY_SUPPORT` to `false` so they
- * get the Object implementation, which is slower but behaves correctly.
  */
-Buffer.TYPED_ARRAY_SUPPORT = global.TYPED_ARRAY_SUPPORT !== undefined
-  ? global.TYPED_ARRAY_SUPPORT
-  : typedArraySupport()
+Buffer.TYPED_ARRAY_SUPPORT = typedArraySupport()
 
-/*
- * Export kMaxLength after typed array support is determined.
- */
-exports.kMaxLength = kMaxLength()
+if (!Buffer.TYPED_ARRAY_SUPPORT) {
+  console.error(
+    'This browser lacks typed array (Uint8Array) support which is required by ' +
+    '`buffer` v5.x. Use v4.x if you require old browser support.')
+}
 
 function typedArraySupport () {
   try {
@@ -60,28 +58,13 @@ function typedArraySupport () {
   }
 }
 
-function kMaxLength () {
-  return Buffer.TYPED_ARRAY_SUPPORT
-    ? 0x7fffffff
-    : 0x3fffffff
-}
-
 function createBuffer (that, length) {
-  if (kMaxLength() < length) {
+  if (K_MAX_LENGTH < length) {
     throw new RangeError('Invalid typed array length')
   }
-  if (Buffer.TYPED_ARRAY_SUPPORT) {
-    // Return an augmented `Uint8Array` instance, for best performance
-    that = new Uint8Array(length)
-    that.__proto__ = Buffer.prototype
-  } else {
-    // Fallback: Return an object instance of the Buffer class
-    if (that === null) {
-      that = new Buffer(length)
-    }
-    that.length = length
-  }
-
+  // Return an augmented `Uint8Array` instance
+  that = new Uint8Array(length)
+  that.__proto__ = Buffer.prototype
   return that
 }
 
@@ -96,10 +79,6 @@ function createBuffer (that, length) {
  */
 
 function Buffer (arg, encodingOrOffset, length) {
-  if (!Buffer.TYPED_ARRAY_SUPPORT && !(this instanceof Buffer)) {
-    return new Buffer(arg, encodingOrOffset, length)
-  }
-
   // Common case.
   if (typeof arg === 'number') {
     if (typeof encodingOrOffset === 'string') {
@@ -112,26 +91,20 @@ function Buffer (arg, encodingOrOffset, length) {
   return from(this, arg, encodingOrOffset, length)
 }
 
-if (Buffer.TYPED_ARRAY_SUPPORT) {
-  Buffer.prototype.__proto__ = Uint8Array.prototype
-  Buffer.__proto__ = Uint8Array
-  if (typeof Symbol !== 'undefined' && Symbol.species &&
-      Buffer[Symbol.species] === Buffer) {
-    // Fix subarray() in ES2016. See: https://github.com/feross/buffer/pull/97
-    Object.defineProperty(Buffer, Symbol.species, {
-      value: null,
-      configurable: true
-    })
-  }
-}
-Buffer.poolSize = 8192 // not used by this implementation
+Buffer.prototype.__proto__ = Uint8Array.prototype
+Buffer.__proto__ = Uint8Array
 
-// TODO: Legacy, not needed anymore. Remove in next major version.
-Buffer._augment = function (arr) {
-  arr.__proto__ = Buffer.prototype
-  return arr
+// Fix subarray() in ES2016. See: https://github.com/feross/buffer/pull/97
+if (typeof Symbol !== 'undefined' && Symbol.species &&
+    Buffer[Symbol.species] === Buffer) {
+  Object.defineProperty(Buffer, Symbol.species, {
+    value: null,
+    configurable: true
+  })
 }
 
+Buffer.poolSize = 8192 // not used by this implementation
+
 function from (that, value, encodingOrOffset, length) {
   if (typeof value === 'number') {
     throw new TypeError('"value" argument must not be a number')
@@ -194,13 +167,7 @@ Buffer.alloc = function (size, fill, encoding) {
 
 function allocUnsafe (that, size) {
   assertSize(size)
-  that = createBuffer(that, size < 0 ? 0 : checked(size) | 0)
-  if (!Buffer.TYPED_ARRAY_SUPPORT) {
-    for (var i = 0; i < size; ++i) {
-      that[i] = 0
-    }
-  }
-  return that
+  return createBuffer(that, size < 0 ? 0 : checked(size) | 0)
 }
 
 /**
@@ -268,14 +235,9 @@ function fromArrayBuffer (that, array, byteOffset, length) {
     array = new Uint8Array(array, byteOffset, length)
   }
 
-  if (Buffer.TYPED_ARRAY_SUPPORT) {
-    // Return an augmented `Uint8Array` instance, for best performance
-    that = array
-    that.__proto__ = Buffer.prototype
-  } else {
-    // Fallback: Return an object instance of the Buffer class
-    that = fromArrayLike(that, array)
-  }
+  // Return an augmented `Uint8Array` instance, for best performance
+  that = array
+  that.__proto__ = Buffer.prototype
   return that
 }
 
@@ -310,11 +272,11 @@ function fromObject (that, obj) {
 }
 
 function checked (length) {
-  // Note: cannot use `length < kMaxLength()` here because that fails when
+  // Note: cannot use `length < K_MAX_LENGTH` here because that fails when
   // length is NaN (which is otherwise coerced to zero.)
-  if (length >= kMaxLength()) {
+  if (length >= K_MAX_LENGTH) {
     throw new RangeError('Attempt to allocate Buffer larger than maximum ' +
-                         'size: 0x' + kMaxLength().toString(16) + ' bytes')
+                         'size: 0x' + K_MAX_LENGTH.toString(16) + ' bytes')
   }
   return length | 0
 }
@@ -698,8 +660,7 @@ function bidirectionalIndexOf (buffer, val, byteOffset, encoding, dir) {
     return arrayIndexOf(buffer, val, byteOffset, encoding, dir)
   } else if (typeof val === 'number') {
     val = val & 0xFF // Search for a byte value [0-255]
-    if (Buffer.TYPED_ARRAY_SUPPORT &&
-        typeof Uint8Array.prototype.indexOf === 'function') {
+    if (typeof Uint8Array.prototype.indexOf === 'function') {
       if (dir) {
         return Uint8Array.prototype.indexOf.call(buffer, val, byteOffset)
       } else {
@@ -1073,18 +1034,8 @@ Buffer.prototype.slice = function slice (start, end) {
 
   if (end < start) end = start
 
-  var newBuf
-  if (Buffer.TYPED_ARRAY_SUPPORT) {
-    newBuf = this.subarray(start, end)
-    newBuf.__proto__ = Buffer.prototype
-  } else {
-    var sliceLen = end - start
-    newBuf = new Buffer(sliceLen, undefined)
-    for (var i = 0; i < sliceLen; ++i) {
-      newBuf[i] = this[i + start]
-    }
-  }
-
+  var newBuf = this.subarray(start, end)
+  newBuf.__proto__ = Buffer.prototype
   return newBuf
 }
 
@@ -1300,29 +1251,16 @@ Buffer.prototype.writeUInt8 = function writeUInt8 (value, offset, noAssert) {
   value = +value
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 1, 0xff, 0)
-  if (!Buffer.TYPED_ARRAY_SUPPORT) value = Math.floor(value)
   this[offset] = (value & 0xff)
   return offset + 1
 }
 
-function objectWriteUInt16 (buf, value, offset, littleEndian) {
-  if (value < 0) value = 0xffff + value + 1
-  for (var i = 0, j = Math.min(buf.length - offset, 2); i < j; ++i) {
-    buf[offset + i] = (value & (0xff << (8 * (littleEndian ? i : 1 - i)))) >>>
-      (littleEndian ? i : 1 - i) * 8
-  }
-}
-
 Buffer.prototype.writeUInt16LE = function writeUInt16LE (value, offset, noAssert) {
   value = +value
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
-  if (Buffer.TYPED_ARRAY_SUPPORT) {
-    this[offset] = (value & 0xff)
-    this[offset + 1] = (value >>> 8)
-  } else {
-    objectWriteUInt16(this, value, offset, true)
-  }
+  this[offset] = (value & 0xff)
+  this[offset + 1] = (value >>> 8)
   return offset + 2
 }
 
@@ -1330,34 +1268,19 @@ Buffer.prototype.writeUInt16BE = function writeUInt16BE (value, offset, noAssert
   value = +value
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
-  if (Buffer.TYPED_ARRAY_SUPPORT) {
-    this[offset] = (value >>> 8)
-    this[offset + 1] = (value & 0xff)
-  } else {
-    objectWriteUInt16(this, value, offset, false)
-  }
+  this[offset] = (value >>> 8)
+  this[offset + 1] = (value & 0xff)
   return offset + 2
 }
 
-function objectWriteUInt32 (buf, value, offset, littleEndian) {
-  if (value < 0) value = 0xffffffff + value + 1
-  for (var i = 0, j = Math.min(buf.length - offset, 4); i < j; ++i) {
-    buf[offset + i] = (value >>> (littleEndian ? i : 3 - i) * 8) & 0xff
-  }
-}
-
 Buffer.prototype.writeUInt32LE = function writeUInt32LE (value, offset, noAssert) {
   value = +value
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0)
-  if (Buffer.TYPED_ARRAY_SUPPORT) {
-    this[offset + 3] = (value >>> 24)
-    this[offset + 2] = (value >>> 16)
-    this[offset + 1] = (value >>> 8)
-    this[offset] = (value & 0xff)
-  } else {
-    objectWriteUInt32(this, value, offset, true)
-  }
+  this[offset + 3] = (value >>> 24)
+  this[offset + 2] = (value >>> 16)
+  this[offset + 1] = (value >>> 8)
+  this[offset] = (value & 0xff)
   return offset + 4
 }
 
@@ -1365,14 +1288,10 @@ Buffer.prototype.writeUInt32BE = function writeUInt32BE (value, offset, noAssert
   value = +value
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0)
-  if (Buffer.TYPED_ARRAY_SUPPORT) {
-    this[offset] = (value >>> 24)
-    this[offset + 1] = (value >>> 16)
-    this[offset + 2] = (value >>> 8)
-    this[offset + 3] = (value & 0xff)
-  } else {
-    objectWriteUInt32(this, value, offset, false)
-  }
+  this[offset] = (value >>> 24)
+  this[offset + 1] = (value >>> 16)
+  this[offset + 2] = (value >>> 8)
+  this[offset + 3] = (value & 0xff)
   return offset + 4
 }
 
@@ -1426,7 +1345,6 @@ Buffer.prototype.writeInt8 = function writeInt8 (value, offset, noAssert) {
   value = +value
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 1, 0x7f, -0x80)
-  if (!Buffer.TYPED_ARRAY_SUPPORT) value = Math.floor(value)
   if (value < 0) value = 0xff + value + 1
   this[offset] = (value & 0xff)
   return offset + 1
@@ -1436,12 +1354,8 @@ Buffer.prototype.writeInt16LE = function writeInt16LE (value, offset, noAssert)
   value = +value
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
-  if (Buffer.TYPED_ARRAY_SUPPORT) {
-    this[offset] = (value & 0xff)
-    this[offset + 1] = (value >>> 8)
-  } else {
-    objectWriteUInt16(this, value, offset, true)
-  }
+  this[offset] = (value & 0xff)
+  this[offset + 1] = (value >>> 8)
   return offset + 2
 }
 
@@ -1449,12 +1363,8 @@ Buffer.prototype.writeInt16BE = function writeInt16BE (value, offset, noAssert)
   value = +value
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
-  if (Buffer.TYPED_ARRAY_SUPPORT) {
-    this[offset] = (value >>> 8)
-    this[offset + 1] = (value & 0xff)
-  } else {
-    objectWriteUInt16(this, value, offset, false)
-  }
+  this[offset] = (value >>> 8)
+  this[offset + 1] = (value & 0xff)
   return offset + 2
 }
 
@@ -1462,14 +1372,10 @@ Buffer.prototype.writeInt32LE = function writeInt32LE (value, offset, noAssert)
   value = +value
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000)
-  if (Buffer.TYPED_ARRAY_SUPPORT) {
-    this[offset] = (value & 0xff)
-    this[offset + 1] = (value >>> 8)
-    this[offset + 2] = (value >>> 16)
-    this[offset + 3] = (value >>> 24)
-  } else {
-    objectWriteUInt32(this, value, offset, true)
-  }
+  this[offset] = (value & 0xff)
+  this[offset + 1] = (value >>> 8)
+  this[offset + 2] = (value >>> 16)
+  this[offset + 3] = (value >>> 24)
   return offset + 4
 }
 
@@ -1478,14 +1384,10 @@ Buffer.prototype.writeInt32BE = function writeInt32BE (value, offset, noAssert)
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000)
   if (value < 0) value = 0xffffffff + value + 1
-  if (Buffer.TYPED_ARRAY_SUPPORT) {
-    this[offset] = (value >>> 24)
-    this[offset + 1] = (value >>> 16)
-    this[offset + 2] = (value >>> 8)
-    this[offset + 3] = (value & 0xff)
-  } else {
-    objectWriteUInt32(this, value, offset, false)
-  }
+  this[offset] = (value >>> 24)
+  this[offset + 1] = (value >>> 16)
+  this[offset + 2] = (value >>> 8)
+  this[offset + 3] = (value & 0xff)
   return offset + 4
 }
 
@@ -1559,7 +1461,7 @@ Buffer.prototype.copy = function copy (target, targetStart, start, end) {
     for (i = len - 1; i >= 0; --i) {
       target[i + targetStart] = this[i + start]
     }
-  } else if (len < 1000 || !Buffer.TYPED_ARRAY_SUPPORT) {
+  } else if (len < 1000) {
     // ascending copy from start
     for (i = 0; i < len; ++i) {
       target[i + targetStart] = this[i + start]