Revision: 17567
Author: [email protected]
Date: Thu Nov 7 14:56:40 2013 UTC
Log: Speed up typed array constructors.
- Avoid calls into ToPositiveInteger for valid cases of 'undefined'
arguments.
(Otherwise it calls into runtime).
- Reduce the checks performed in case offset for TypedArrayFromArrayBuffer
constructor is called with no offset argument.
[email protected]
Review URL: https://codereview.chromium.org/59763010
http://code.google.com/p/v8/source/detail?r=17567
Modified:
/branches/bleeding_edge/src/typedarray.js
=======================================
--- /branches/bleeding_edge/src/typedarray.js Wed Nov 6 16:28:38 2013 UTC
+++ /branches/bleeding_edge/src/typedarray.js Thu Nov 7 14:56:40 2013 UTC
@@ -49,15 +49,20 @@
macro TYPED_ARRAY_CONSTRUCTOR(ARRAY_ID, NAME, ELEMENT_SIZE)
function NAMEConstructByArrayBuffer(obj, buffer, byteOffset, length) {
- var offset =
ToPositiveInteger(byteOffset, "invalid_typed_array_length")
+ var bufferByteLength = buffer.byteLength;
+ var offset;
+ if (IS_UNDEFINED(byteOffset)) {
+ offset = 0;
+ } else {
+ offset = ToPositiveInteger(byteOffset, "invalid_typed_array_length");
- if (offset % ELEMENT_SIZE !== 0) {
- throw MakeRangeError("invalid_typed_array_alignment",
- "start offset", "NAME", ELEMENT_SIZE);
- }
- var bufferByteLength = buffer.byteLength;
- if (offset > bufferByteLength) {
- throw MakeRangeError("invalid_typed_array_offset");
+ if (offset % ELEMENT_SIZE !== 0) {
+ throw MakeRangeError("invalid_typed_array_alignment",
+ "start offset", "NAME", ELEMENT_SIZE);
+ }
+ if (offset > bufferByteLength) {
+ throw MakeRangeError("invalid_typed_array_offset");
+ }
}
var newByteLength;
@@ -80,7 +85,8 @@
}
function NAMEConstructByLength(obj, length) {
- var l = ToPositiveInteger(length, "invalid_typed_array_length");
+ var l = IS_UNDEFINED(length) ?
+ 0 : ToPositiveInteger(length, "invalid_typed_array_length");
var byteLength = l * ELEMENT_SIZE;
var buffer = new $ArrayBuffer(byteLength);
%TypedArrayInitialize(obj, ARRAY_ID, buffer, 0, byteLength);
@@ -301,7 +307,8 @@
throw MakeTypeError('data_view_not_array_buffer', []);
}
var bufferByteLength = %ArrayBufferGetByteLength(buffer);
- var offset = ToPositiveInteger(byteOffset, 'invalid_data_view_offset');
+ var offset = IS_UNDEFINED(byteOffset) ?
+ 0 : ToPositiveInteger(byteOffset, 'invalid_data_view_offset');
if (offset > bufferByteLength) {
throw MakeRangeError('invalid_data_view_offset');
}
--
--
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