Merge branch 'master' of github.com:lemire/JavaFastPFOR

Author: lemire

.github/workflows/basic.yml

@@ -8,11 +8,11 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: [ 11, 16 ]
+        java: [ 17, 21 ]
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4.1.1
       - name: Set up JDK
-        uses: actions/setup-java@v2.5.0
+        uses: actions/setup-java@v4.1.0
         with:
           java-version: ${{ matrix.java }}
           distribution: 'adopt'
@@ -21,4 +21,4 @@ jobs:
       - name: Build example
         run: javac -cp target/classes/:. example.java
       - name: Run example
-        run: java -cp target/classes/:. example
+        run: java -cp target/classes/:. example

README.md

@@ -1,7 +1,6 @@
 JavaFastPFOR: A simple integer compression library in Java 
 ==========================================================
  [![][maven img]][maven] [![][license img]][license] [![docs-badge][]][docs]
-[![Code Quality: Cpp](https://img.shields.io/lgtm/grade/java/g/lemire/JavaFastPFOR.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/lemire/JavaFastPFOR/context:java)
 [![Java CI](https://github.com/lemire/JavaFastPFOR/actions/workflows/basic.yml/badge.svg)](https://github.com/lemire/JavaFastPFOR/actions/workflows/basic.yml)
 
 
@@ -82,9 +81,9 @@ the following code in your pom.xml file:
 ```xml
     <dependencies>
          <dependency>
-         <groupId>me.lemire.integercompression</groupId>
-         <artifactId>JavaFastPFOR</artifactId>
-         <version>[0.1,)</version>
+	     <groupId>me.lemire.integercompression</groupId>
+	     <artifactId>JavaFastPFOR</artifactId>
+	     <version>[0.2,)</version>
          </dependency>
      </dependencies>
 ```
@@ -222,6 +221,7 @@ He also posted his slides online: http://www.slideshare.net/ikhtearSharif/ikhtea
 Other recommended libraries
 -----------------------------
 
+* Fast integer compression in Go: https://github.com/ronanh/intcomp
 * Encoding: Integer Compression Libraries for Go https://github.com/zhenjl/encoding
 * CSharpFastPFOR: A C#  integer compression library  https://github.com/Genbox/CSharpFastPFOR
 * TurboPFor is a C library that offers lots of interesting optimizations and Java wrappers. Well worth checking! (Uses a GPL license.) https://github.com/powturbo/TurboPFor

pom.xml

@@ -2,7 +2,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>me.lemire.integercompression</groupId>
   <artifactId>JavaFastPFOR</artifactId>
-  <version>0.1.13-SNAPSHOT</version>
+  <version>0.2.2-SNAPSHOT</version>
   <packaging>jar</packaging>
   <properties>
     <maven.compiler.source>1.8</maven.compiler.source>
@@ -69,10 +69,10 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-compiler-plugin</artifactId>
-        <version>3.8.0</version>
+        <version>3.12.1</version>
         <configuration>
-            <source>11</source>
-            <target>11</target>
+            <source>17</source>
+            <target>17</target>
         </configuration>
         <executions>
           <execution>
@@ -138,7 +138,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-javadoc-plugin</artifactId>
-        <version>3.4.1</version>
+        <version>3.6.3</version>
         <configuration>
             <excludePackageNames>me.lemire.integercompression.vector;com.kamikaze.pfordelta:me.lemire.integercompression.benchmarktools</excludePackageNames>
        </configuration>

src/main/java/me/lemire/integercompression/BitPacking.java

@@ -1690,7 +1690,7 @@ protected static void fastpack9(final int[] in, int inpos,
         }
 
         /**
-         * Unpack 32 integers
+         * Pack without mask 32 integers
          * 
          * @param in
          *                source array
@@ -3005,7 +3005,7 @@ protected static void fastpackwithoutmask9(final int[] in, int inpos,
         }
 
         /**
-         * Pack the 32 integers
+         * Unpack the 32 integers
          * 
          * @param in
          *                source array

src/main/java/me/lemire/integercompression/DeltaZigzagVariableByte.java

@@ -134,6 +134,9 @@ public void uncompress(int[] inBuf, IntWrapper inPos, int inLen,
          * In case you need a different way to allocate buffers, you can override this method
          * with a custom behavior. The default implementation allocates a new Java direct
          * {@link ByteBuffer} on each invocation.
+         * 
+         * @param sizeInBytes
+         * @return
          */
         protected ByteBuffer makeBuffer(int sizeInBytes) {
                 return ByteBuffer.allocateDirect(sizeInBytes);

src/main/java/me/lemire/integercompression/FastPFOR.java

@@ -336,6 +336,9 @@ public String toString() {
          * In case you need a different way to allocate buffers, you can override this method
          * with a custom behavior. The default implementation allocates a new Java direct
          * {@link ByteBuffer} on each invocation.
+         * 
+         * @param sizeInBytes
+         * @return
          */
         protected ByteBuffer makeBuffer(int sizeInBytes) {
             return ByteBuffer.allocateDirect(sizeInBytes);

src/main/java/me/lemire/integercompression/FastPFOR128.java

@@ -317,6 +317,9 @@ public String toString() {
          * In case you need a different way to allocate buffers, you can override this method
          * with a custom behavior. The default implementation allocates a new Java direct
          * {@link ByteBuffer} on each invocation.
+         * 
+         * @param sizeInBytes
+         * @return
          */
         protected ByteBuffer makeBuffer(int sizeInBytes) {
             return ByteBuffer.allocateDirect(sizeInBytes);

src/main/java/me/lemire/integercompression/IntCompressor.java

@@ -36,7 +36,8 @@ public IntCompressor() {
      * @throws UncompressibleInputException if the data is too poorly compressible
      */
     public  int[] compress(int[] input) {
-        int [] compressed = new int[input.length + input.length / 100 + 1024];
+        int[] compressed = new int[input.length + input.length / 100 + 1024];
+        // Store at index=0 the length of the input, hence enabling .headlessCompress
         compressed[0] = input.length;
         IntWrapper outpos = new IntWrapper(1);
         try {
@@ -58,6 +59,7 @@ public  int[] compress(int[] input) {
      * @return uncompressed array
      */
     public int[] uncompress(int[] compressed) {
+        // Read at index=0 the length of the input, hence enabling .headlessUncompress
         int[] decompressed = new int[compressed[0]];
         IntWrapper inpos = new IntWrapper(1);
         codec.headlessUncompress(compressed, inpos, 

src/main/java/me/lemire/integercompression/IntegerCODEC.java

@@ -25,7 +25,7 @@ public interface IntegerCODEC {
          * @param in
          *                input array
          * @param inpos
-         *                location in the input array
+         *                where to start reading in the array
          * @param inlength
          *                how many integers to compress
          * @param out
@@ -52,7 +52,7 @@ public void compress(int[] in, IntWrapper inpos, int inlength,
          * @param out
          *                array where to write the compressed output
          * @param outpos
-         *                where to write the compressed output in out
+         *                where to start writing the uncompressed output in out
          */
         public void uncompress(int[] in, IntWrapper inpos, int inlength,
                 int[] out, IntWrapper outpos);

src/main/java/me/lemire/integercompression/SkippableIntegerCODEC.java

@@ -13,8 +13,8 @@
  * variation on the IntegerCODEC interface meant to be used for random access
  * (i.e., given a large array, you can segment it and decode just the subarray you need).
  * 
- * The main difference is that we must specify the number of integers we wish to
- * decode. This information should be stored elsewhere.
+ * The main difference is that you must specify the number of integers you wish to
+ * uncompress. This information should be stored elsewhere.
  * 
  * This interface was designed by the Terrier team for their search engine.
  * 
@@ -30,10 +30,13 @@ public interface SkippableIntegerCODEC {
      * inpos will be incremented by 12 while outpos will be incremented by 3. We
      * use IntWrapper to pass the values by reference.
      * 
+     * Implementation note: contrary to {@link IntegerCODEC#compress},
+     * this may skip writing information about the number of encoded integers.
+     * 
      * @param in
      *            input array
      * @param inpos
-     *            location in the input array
+     *            where to start reading in the array
      * @param inlength
      *            how many integers to compress
      * @param out
@@ -57,11 +60,11 @@ public void headlessCompress(int[] in, IntWrapper inpos, int inlength, int[] out
      * @param inlength
      *            length of the compressed data (ignored by some schemes)
      * @param out
-     *            array where to write the compressed output
+     *            array where to write the uncompressed output
      * @param outpos
-     *            where to write the compressed output in out
+     *            where to start writing the uncompressed output in out
      * @param num
-     *            number of integers we want to decode, the actual number of integers decoded can be less
+     *            number of integers we want to decode. May be less than the actual number of compressed integers
      */
     public void headlessUncompress(int[] in, IntWrapper inpos, int inlength, int[] out,
             IntWrapper outpos, int num);