Skip to content

Read bytes more efficiently #2137

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
stephengold merged 7 commits into from
Nov 17, 2023
Merged

Read bytes more efficiently #2137

Changes from 1 commit
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
4fe0b4b
Read bytes more efficiently
tonihele Oct 29, 2023
9fe71f9
Read straight to the buffer
tonihele Nov 1, 2023
e4b9049
Epsilon as final
tonihele Nov 1, 2023
3c4af6f
Simple assert for reading malformed stream
tonihele Nov 1, 2023
28c2421
Stream might not have reached the end even if it doesn't return reque…
tonihele Nov 4, 2023
eafb19a
Stream might not have reached the end even if it doesn't return reque…
tonihele Nov 4, 2023
f8f884f
Refactor to method
tonihele Nov 4, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 13 additions & 4 deletions jme3-plugins/src/gltf/java/com/jme3/scene/plugins/gltf/GltfUtils.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -425,12 +425,21 @@ private static void populateByteArray(byte[] array, LittleEndien stream, int cou
int stride = Math.max(dataLength, byteStride);
int end = count * stride + byteOffset;
stream.skipBytes(byteOffset);

if (dataLength == stride) {
byte[] buffer = new byte[end - index];
stream.read(buffer, 0, buffer.length);
Copy link
Contributor

@pspeed42 pspeed42 Oct 29, 2023 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Note: read() may read fewer bytes than buffer.length and it's bad practice to ignore its return value. I'd suggest using readFully() instead but JME's LittleEndien.readFully() is broken in a similar way. This is a really dangerous way to read because failures will look really strange and not necessarily point to this read() code.

System.arraycopy(buffer, 0, array, 0, buffer.length);

return;
}

int arrayIndex = 0;
byte[] buffer = new byte[numComponents];
while (index < end) {
for (int i = 0; i < numComponents; i++) {
array[arrayIndex] = stream.readByte();
arrayIndex++;
}
stream.read(buffer, 0, numComponents);
System.arraycopy(buffer, 0, array, arrayIndex, numComponents);
arrayIndex += numComponents;
if (dataLength < stride) {
stream.skipBytes(stride - dataLength);
}
Expand Down