Find a string inside a bytebuffer

Question

I'm switching from C to Java. I'm wondering about how to find a string inside a bytebuffer, is there something like memchr in java? The bytebuffer is only partly a string, the rest is raw bytes so any java method has to work on bytes + chars.

I am also searching for something like strsep in java to split strings.

Answer 1

You can convert the ByteBuffer into a String and use indexOf which likely to work.

ByteBuffer bb = /* non-direct byte buffer */
String text = new String(bb.array(), 0, bb.position(), bb.remaing());
int index = text.indexOf(searchText);

This has a non-trivial overhead as it creates a String. The alternative is a brute force String search which will be faster but takes time to write.

Answer 2

You would need to encode the character string into bytes using the correct character encoding for your application. Then use a string search algorithm like Rabin-Karp or Boyer-Moore to find the resulting byte sequence within the buffer. Or, if your buffers are small, you could just perform a brute force search.

I'm not aware of any open source implementations of these search algorithms, and they aren't part of core Java.