On Tue, 12 Apr 2022 22:15:22 GMT, XenoAmess <d...@openjdk.java.net> wrote:
> What subclasses of InputStream in the JDK do not override skip(n)? >From a peek, the majority of subclasses do not override `skip(long)`. Most >overrides are delegations or optimizations for random access structures; but >there are some that create their custom local variable skip buffers, usually >of size 512 or minimum of 512 and the skip size. These custom skip buffer ones >IMO should have their overrides removed. > Most sequential streams are open for a relatively short period of time, the > lifetime of the > memory for the buffer won't change the memory usage enough to notice. True, and with good use of try-with-resources, these instance fields' array allocations shouldn't be too much of a problem compared to allocation in every skip(long) call. > If the concern is about tying up memory then allocate the buffer once and don't resize it. Each resize consumes extra memory and gc cycles to reclaim the last buffer. > Use the requested size but at least nnn and at most MAX_SKIP_BUFFER_SIZE. Shouldn't be too problematic, as most skip usages in JDK as I see are skipping small number of bytes like 2 or 4, or like skipping over attributes of Java class files. A minimum skip buffer size isn't that helpful, as I don't think we often see skip calls with slowly incremental sizes. ------------- PR: https://git.openjdk.java.net/jdk/pull/5872
