README.txt

create via:

mvn archetype:generate -DinteractiveMode=false -DarchetypeGroupId=org.openjdk.jmh -DarchetypeArtifactId=jmh-java-benchmark-archetype -DgroupId=com.zwitserloot -DartifactId=boyermoore -Dversion=1.0

MyBenchmark.java

package com.zwitserloot;

import org.openjdk.jmh.annotations.*;
import java.nio.charset.*;
import java.util.Arrays;

public class MyBenchmark {
	private static final int HAYSTACK_SIZE = 100;
	
	public static void main(String[] args) {
		MyState s = new MyState();
		s.setup();
		MyBenchmark b = new MyBenchmark();
		int idx1 = b.java(s);
		int idx2 = b.boyerMoore(s);
		int w = s.HAYSTACK.length() - s.NEEDLE.length();
		if (idx1 != w) System.out.println("java code broken");
		if (idx2 != w) System.out.println("B-M code broken");
	}
	
	@State(Scope.Benchmark)
	public static class MyState {
		public String NEEDLE, HAYSTACK;
		public byte[] _NEEDLE, _HAYSTACK;
		
		@Setup(Level.Trial)
		public void setup() {
			Charset cs = StandardCharsets.US_ASCII;
			
			byte[] base = "Hello, world! I am a string; perhaps I can ananate how, for ananananananars, and more!".getBytes(cs);
			byte[] answer = "ananas".getBytes(cs);
			_HAYSTACK = new byte[base.length * HAYSTACK_SIZE + answer.length];
			_NEEDLE = answer;
			NEEDLE = new String(_NEEDLE, cs);
			for (int i = 0; i < HAYSTACK_SIZE; i++) System.arraycopy(base, 0, _HAYSTACK, base.length * i, base.length);
			System.arraycopy(answer, 0, _HAYSTACK, base.length * HAYSTACK_SIZE, answer.length);
			HAYSTACK = new String(_HAYSTACK, cs);
		}
	}
	
	@Benchmark
	public int java(MyState state) {
		return state.HAYSTACK.indexOf(state.NEEDLE);
	}
	
	@Benchmark
	public int boyerMoore(MyState state) {
		byte[] NEEDLE = state._NEEDLE, HAYSTACK = state._HAYSTACK;
		
		if (NEEDLE.length == 0) return 0;
		int[] ct = makeCharTable(NEEDLE);
		int[] ot = makeOffsetTable(NEEDLE);
		
		for (int i = NEEDLE.length - 1, j; i < HAYSTACK.length;) {
			for (j = NEEDLE.length - 1; NEEDLE[j] == HAYSTACK[i]; --i, --j) {
				if (j == 0) return i;
			}
			i += Math.max(ot[NEEDLE.length - 1 - j], ct[HAYSTACK[i]]);
		}
		
		return -1;
	}
	
	private static int[] makeCharTable(byte[] needle) {
		final int A = 128, len = needle.length;
		int[] t = new int[A];
		Arrays.fill(t, len);
		for (int i = 0; i < len - 2; i++) t[needle[i]] = len - 1 - i;
		return t;
	}
	
	private static int[] makeOffsetTable(byte[] needle) {
		int len = needle.length;
		int[] t = new int[len];
		int lastPrefixPosition = len;
		for (int i = len; i > 0; --i) {
			if (isPrefix(needle, i)) lastPrefixPosition = i;
			t[len - i] = lastPrefixPosition - i + len;
		}
		for (int i = 0; i < len - 1; i++) {
			int sLen = suffixLength(needle, i);
			t[sLen] = len - 1 - i + sLen;
		}
		
		return t;
	}
	
	private static boolean isPrefix(byte[] needle, int p) {
		for (int i = p, j = 0; i < needle.length; ++i, ++j) if (needle[i] != needle[j]) return false;
		return true;
	}
	
	private static int suffixLength(byte[] needle, int p) {
		int len = 0;
		for (int i = p, j = needle.length - 1; i >= 0 && needle[i] == needle[j]; --i, --j) len++;
		return len;
	}
}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.zwitserloot</groupId>
    <artifactId>boyermoore</artifactId>
    <version>1.0</version>
    <packaging>jar</packaging>

    <name>JMH benchmark sample: Java</name>

    <!--
       This is the demo/sample template build script for building Java benchmarks with JMH.
       Edit as needed.
    -->

    <dependencies>
        <dependency>
            <groupId>org.openjdk.jmh</groupId>
            <artifactId>jmh-core</artifactId>
            <version>${jmh.version}</version>
        </dependency>
        <dependency>
            <groupId>org.openjdk.jmh</groupId>
            <artifactId>jmh-generator-annprocess</artifactId>
            <version>${jmh.version}</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

        <!--
            JMH version to use with this project.
          -->
        <jmh.version>1.22</jmh.version>

        <!--
            Java source/target to use for compilation.
          -->
        <javac.target>1.8</javac.target>

        <!--
            Name of the benchmark Uber-JAR to generate.
          -->
        <uberjar.name>benchmarks</uberjar.name>
    </properties>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.0</version>
                <configuration>
                    <compilerVersion>${javac.target}</compilerVersion>
                    <source>${javac.target}</source>
                    <target>${javac.target}</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.2.1</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <finalName>${uberjar.name}</finalName>
                            <transformers>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>org.openjdk.jmh.Main</mainClass>
                                </transformer>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
                            </transformers>
                            <filters>
                                <filter>
                                    <!--
                                        Shading signed JARs will fail without this.
                                        http://stackoverflow.com/questions/999489/invalid-signature-file-when-attempting-to-run-a-jar
                                    -->
                                    <artifact>*:*</artifact>
                                    <excludes>
                                        <exclude>META-INF/*.SF</exclude>
                                        <exclude>META-INF/*.DSA</exclude>
                                        <exclude>META-INF/*.RSA</exclude>
                                    </excludes>
                                </filter>
                            </filters>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
        <pluginManagement>
            <plugins>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>2.5</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-jar-plugin</artifactId>
                    <version>2.4</version>
                </plugin>
                <plugin>
                    <artifactId>maven-javadoc-plugin</artifactId>
                    <version>2.9.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>2.6</version>
                </plugin>
                <plugin>
                    <artifactId>maven-site-plugin</artifactId>
                    <version>3.3</version>
                </plugin>
                <plugin>
                    <artifactId>maven-source-plugin</artifactId>
                    <version>2.2.1</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.17</version>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>

</project>