How can I make an IntStream from a byte array?

问题

I already know there are only IntStream and LongStream. How can I make an IntStream from a byte array?

Currently I'm planning to do like this.

static int[] bytesToInts(final byte[] bytes) {
    final int[] ints = new int[bytes.length];
    for (int i = 0; i < ints.length; i++) {
        ints[i] = bytes[i] & 0xFF;
    }
    return ints;
}

static IntStream bytesToIntStream(final byte[] bytes) {
    return IntStream.of(bytesToInt(bytes));
}

Is there any easier or faster way to do this?

回答1:

A variant of Radiodef's answer:

static IntStream bytesToIntStream(byte[] bytes) {
    return IntStream.range(0, bytes.length)
        .map(i -> bytes[i] & 0xFF)
    ;
}

Easier to guarantee parallelization, too.

回答2:

You could do something like

static IntStream bytesToIntStream(byte[] bytes) {
    AtomicInteger i = new AtomicInteger();
    return IntStream
        .generate(() -> bytes[i.getAndIncrement()] & 0xFF)
        .limit(bytes.length);
}

but it's not very pretty. (It's not so bad though: usage of AtomicInteger allows the stream to be run in parallel.)

回答3:

One line code:

import com.google.common.primitives.Bytes;
IntStream in = Bytes.asList(bytes).stream().mapToInt(i-> i & 0xFF);

来源：https://stackoverflow.com/questions/27181026/how-can-i-make-an-intstream-from-a-byte-array