Sakurai/pdf.js
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Optimize the Ref class in src/core/primitives.js

Browse Source 
The `toString` method always creates two string objects (for the 'R'
character and for the `num` concatenation) and in the worst case
creates three string objects (one more for the `gen` concatenation).
For the Tracemonkey paper alone, this resulted in 12000 string
objects when scrolling from the top to the bottom of the document.
Since this is a hot function, it's worth minimizing the number of string
objects, especially for large documents, to reduce peak memory usage.

This commit refactors the `toString` method to always create only one
string object.
This commit is contained in:
Tim van der Meij 2018-12-29 17:33:55 +01:00
parent e53877f372
commit aad27ff9a0
No known key found for this signature in database
GPG Key ID: 8C3FD2925A5F2762
1 changed files with 2 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
src/core/primitives.js
View File

@ -185,11 +185,10 @@ var Ref = (function RefClosure() {
toString: function Ref_toString() { toString: function Ref_toString() {
// This function is hot, so we make the string as compact as possible. // This function is hot, so we make the string as compact as possible.
// |this.gen| is almost always zero, so we treat that case specially. // |this.gen| is almost always zero, so we treat that case specially.
var str = this.num + 'R';
if (this.gen !== 0) { if (this.gen !== 0) {
str += this.gen; return `${this.num}R${this.gen}`;
} }
return str; return `${this.num}R`;
}, },
}; };