mirrors/pdf.js
1
0
Fork 0
mirror of https://github.com/mozilla/pdf.js.git synced 2025-04-26 01:58:06 +02:00
Code Activity

Estimate the size of decoded streams in advance.

Browse source 
When decoding a stream, the decode buffer is often grown multiple times, its
byte size increasing like so: 512, 1024, 2048, etc. This patch estimates the
minimum size in advance (using the length of the encoded stream), often
allowing the smaller sizes to be skipped. It also renames numerous |length|
variables as |maybeLength| to make it clear that they can be |null|.

I measured this change on eight documents. This change reduces the cumulative
size of decode buffer allocations by 0--32%, with 10--20% being typical. This
reduces peak RSS by 10 or 20 MiB for several of them.
This commit is contained in:
Nicholas Nethercote 2014-03-10 22:18:30 -07:00
parent c3ed71c9c5
commit b3024db677
5 changed files with 85 additions and 60 deletions
Download patch file Download diff file Expand all files Collapse all files

4
src/core/crypto.js
View file

@ -431,9 +431,9 @@ var CipherTransform = (function CipherTransformClosure() {
this.streamCipherConstructor = streamCipherConstructor;
}
CipherTransform.prototype = {
createStream: function CipherTransform_createStream(stream) {
createStream: function CipherTransform_createStream(stream, length) {
var cipher = new this.streamCipherConstructor();
return new DecryptStream(stream,
return new DecryptStream(stream, length,
function cipherTransformDecryptStream(data, finalize) {
return cipher.decryptBlock(data, finalize);
}