Skip to content
This repository was archived by the owner on Dec 2, 2025. It is now read-only.

Avoid Exception-related performance issues in LZ4BlockInputStream when stopOnEmptyBlock == false #143

Merged
odaira merged 1 commit into from
Aug 30, 2019
Merged

Avoid Exception-related performance issues in LZ4BlockInputStream when stopOnEmptyBlock == false #143

Changes from all commits
Commits
Show all changes
1 commit
Select commit
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
19 changes: 13 additions & 6 deletions src/java/net/jpountz/lz4/LZ4BlockInputStream.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -187,13 +187,11 @@ public long skip(long n) throws IOException {
}

private void refill() throws IOException {
try {
readFully(compressedBuffer, HEADER_LENGTH);
} catch (EOFException e) {
if (!tryReadFully(compressedBuffer, HEADER_LENGTH)) {
if (!stopOnEmptyBlock) {
finished = true;
} else {
throw e;
throw new EOFException("Stream ended prematurely");
}
return;
}
Expand Down Expand Up @@ -263,16 +261,25 @@ private void refill() throws IOException {
o = 0;
}

private void readFully(byte[] b, int len) throws IOException {
// Like readFully(), except it signals incomplete reads by returning
// false instead of throwing EOFException.
private boolean tryReadFully(byte[] b, int len) throws IOException {
Copy link
Contributor

@maropu maropu Jun 28, 2019

Choose a reason for hiding this comment

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

nit: drop throws IOException in the end.

Copy link
Contributor Author

@JoshRosen JoshRosen Jun 28, 2019

Choose a reason for hiding this comment

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

I considered this, but it will not work: the underlying read() call declares that it throws IOException so we need to keep this here.

Copy link
Contributor

@maropu maropu Jun 29, 2019

Choose a reason for hiding this comment

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

ah, ok.

int read = 0;
while (read < len) {
final int r = in.read(b, read, len - read);
if (r < 0) {
throw new EOFException("Stream ended prematurely");
return false;
}
read += r;
}
assert len == read;
return true;
}

private void readFully(byte[] b, int len) throws IOException {
if (!tryReadFully(b, len)) {
throw new EOFException("Stream ended prematurely");
}
}

@Override
Expand Down