hyperxpro/Brotli4j

Unable to compress correctly if input data does not start from 0.

deshanxiao opened this issue · 5 comments

deshanxiao commented

Describe the bug
Unable to compress correctly if input data does not start from 0.

To Reproduce
Call Encoder.compress(byte[] x, int offset, int length) will compress all bytes from x (offset > 0)

Brotli4j/brotli4j/src/main/java/com/aayushatharva/brotli4j/encoder/Encoder.java

Line 73 in 0907a38

encoder.push(EncoderJNI.Operation.FINISH, data.length);

data.length -> length ?

Expected behavior
It should only compress the bytes from start to start + len.

Platform (please complete the following information):
ubuntu

Additional context

hyperxpro commented

What is the error? Are you getting corrupted data?

hyperxpro commented

Technically, you should compress all data and then finish the encoding with length 0.

deshanxiao commented

I got no error but the output array looks unexpected in length. Here is a very simple example: @hyperxpro

public class Main2 {
    static {
        Brotli4jLoader.ensureAvailability();
    }

    public static void main(String[] args) throws IOException {
        byte[] totalBytes = "abcdefg".getBytes();
        // compress "defg"
        byte[] compressedBytes = Encoder.compress(totalBytes, 3, 4);
        // len(output) == 7 not 4
        byte[] output = Decoder.decompress(compressedBytes, 0, compressedBytes.length);
    }
}
hyperxpro commented

Okay, looks like a bug.

Would you like to raise a PR at https://github.com/google/brotli?