BitapSearchProcessorFactory Class — netty Architecture

Source Code

buffer/src/main/java/io/netty/buffer/search/BitapSearchProcessorFactory.java lines 27–77

public class BitapSearchProcessorFactory extends AbstractSearchProcessorFactory {

    private final long[] bitMasks = new long[256];
    private final long successBit;

    public static class Processor implements SearchProcessor {

        private final long[] bitMasks;
        private final long successBit;
        private long currentMask;

        Processor(long[] bitMasks, long successBit) {
            this.bitMasks = bitMasks;
            this.successBit = successBit;
        }

        @Override
        public boolean process(byte value) {
            currentMask = ((currentMask << 1) | 1) & PlatformDependent.getLong(bitMasks, value & 0xffL);
            return (currentMask & successBit) == 0;
        }

        @Override
        public void reset() {
            currentMask = 0;
        }
    }

    BitapSearchProcessorFactory(byte[] needle) {
        if (needle.length > 64) {
            throw new IllegalArgumentException("Maximum supported search pattern length is 64, got " + needle.length);
        }

        long bit = 1L;
        for (byte c: needle) {
            bitMasks[c & 0xff] |= bit;
            bit <<= 1;
        }

        successBit = 1L << (needle.length - 1);
    }

    /**
     * Returns a new {@link Processor}.
     */
    @Override
    public Processor newSearchProcessor() {
        return new Processor(bitMasks, successBit);
    }

}