[CODEC-276] Reliance on default encoding in MurmurHash2 and MurmurHash3.

Author: garydgregory

src/changes/changes.xml

@@ -55,6 +55,7 @@ The <action> type attribute can be add,update,fix,remove.
       <action issue="CODEC-273" dev="ggregory" type="add" due-to="Gary Gregory">Add Path APIs to org.apache.commons.codec.digest.DigestUtils similar to File APIs.</action>
       <action issue="CODEC-274" dev="ggregory" type="add" due-to="Gary Gregory">Add SHA-512/224 and SHA-512/256 to DigestUtils for Java 9 and up.</action>
       <action issue="CODEC-275" dev="ggregory" type="add" due-to="Claude Warren">Add missing note in javadoc when sign extension error is present #34.</action>
+      <action issue="CODEC-276" dev="ggregory" type="add" due-to="Gary Gregory">Reliance on default encoding in MurmurHash2 and MurmurHash3.</action>
     </release>
 
     <release version="1.13" date="2019-07-20" description="Feature and fix release.">

src/main/java/org/apache/commons/codec/digest/MurmurHash2.java

@@ -17,6 +17,9 @@
 
 package org.apache.commons.codec.digest;
 
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+
 /**
  * Implementation of the MurmurHash2 32-bit and 64-bit hash functions.
  *
@@ -48,6 +51,13 @@
  */
 public final class MurmurHash2 {
 
+    /**
+     * Default Charset used to convert strings into bytes.
+     * 
+     * Consider private; package private for tests only.
+     */
+    static final Charset GET_BYTES_CHARSET = StandardCharsets.UTF_8;
+
     // Constants for 32-bit variant
     private static final int M32 = 0x5bd1e995;
     private static final int R32 = 24;
@@ -132,7 +142,7 @@ public static int hash32(final byte[] data, final int length) {
      *
      * <pre>
      * int seed = 0x9747b28c;
-     * byte[] bytes = data.getBytes();
+     * byte[] bytes = data.getBytes(StandardCharsets.UTF_8);
      * int hash = MurmurHash2.hash32(bytes, bytes.length, seed);
      * </pre>
      *
@@ -141,7 +151,7 @@ public static int hash32(final byte[] data, final int length) {
      * @see #hash32(byte[], int, int)
      */
     public static int hash32(final String text) {
-        final byte[] bytes = text.getBytes();
+        final byte[] bytes = text.getBytes(GET_BYTES_CHARSET);
         return hash32(bytes, bytes.length);
     }
 
@@ -152,7 +162,7 @@ public static int hash32(final String text) {
      *
      * <pre>
      * int seed = 0x9747b28c;
-     * byte[] bytes = text.substring(from, from + length).getBytes();
+     * byte[] bytes = text.substring(from, from + length).getBytes(StandardCharsets.UTF_8);
      * int hash = MurmurHash2.hash32(bytes, bytes.length, seed);
      * </pre>
      *
@@ -243,7 +253,7 @@ public static long hash64(final byte[] data, final int length) {
      *
      * <pre>
      * int seed = 0xe17a1465;
-     * byte[] bytes = data.getBytes();
+     * byte[] bytes = data.getBytes(StandardCharsets.UTF_8);
      * int hash = MurmurHash2.hash64(bytes, bytes.length, seed);
      * </pre>
      *
@@ -252,7 +262,7 @@ public static long hash64(final byte[] data, final int length) {
      * @see #hash64(byte[], int, int)
      */
     public static long hash64(final String text) {
-        final byte[] bytes = text.getBytes();
+        final byte[] bytes = text.getBytes(GET_BYTES_CHARSET);
         return hash64(bytes, bytes.length);
     }
 
@@ -263,7 +273,7 @@ public static long hash64(final String text) {
      *
      * <pre>
      * int seed = 0xe17a1465;
-     * byte[] bytes = text.substring(from, from + length).getBytes();
+     * byte[] bytes = text.substring(from, from + length).getBytes(StandardCharsets.UTF_8);
      * int hash = MurmurHash2.hash64(bytes, bytes.length, seed);
      * </pre>
      *

src/main/java/org/apache/commons/codec/digest/MurmurHash3.java

@@ -17,6 +17,9 @@
 
 package org.apache.commons.codec.digest;
 
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+
 /**
  * Implementation of the MurmurHash3 32-bit and 128-bit hash functions.
  *
@@ -55,6 +58,13 @@
  */
 public final class MurmurHash3 {
 
+    /**
+     * Default Charset used to convert strings into bytes.
+     * 
+     * Consider private; package private for tests only.
+     */
+    static final Charset GET_BYTES_CHARSET = StandardCharsets.UTF_8;
+
     /**
      * A random number to use for a hash code.
      *
@@ -233,7 +243,7 @@ public static int hash32(final byte[] data) {
      * <pre>
      * int offset = 0;
      * int seed = 104729;
-     * byte[] bytes = data.getBytes();
+     * byte[] bytes = data.getBytes(StandardCharsets.UTF_8);
      * int hash = MurmurHash3.hash32(bytes, offset, bytes.length, seed);
      * </pre>
      *
@@ -249,7 +259,7 @@ public static int hash32(final byte[] data) {
      */
     @Deprecated
     public static int hash32(final String data) {
-        final byte[] bytes = data.getBytes();
+        final byte[] bytes = data.getBytes(GET_BYTES_CHARSET);
         return hash32(bytes, 0, bytes.length, DEFAULT_SEED);
     }
 
@@ -751,7 +761,7 @@ public static long[] hash128x64(final byte[] data) {
      * <pre>
      * int offset = 0;
      * int seed = 104729;
-     * byte[] bytes = data.getBytes();
+     * byte[] bytes = data.getBytes(StandardCharsets.UTF_8);
      * int hash = MurmurHash3.hash128(bytes, offset, bytes.length, seed);
      * </pre>
      *
@@ -766,7 +776,7 @@ public static long[] hash128x64(final byte[] data) {
      */
     @Deprecated
     public static long[] hash128(final String data) {
-        final byte[] bytes = data.getBytes();
+        final byte[] bytes = data.getBytes(GET_BYTES_CHARSET);
         return hash128(bytes, 0, bytes.length, DEFAULT_SEED);
     }
 

src/test/java/org/apache/commons/codec/digest/MurmurHash3Test.java

@@ -355,7 +355,7 @@ public void testHash32String() {
                 pos += Character.toChars(codePoint, chars, pos);
             }
             final String text = String.copyValueOf(chars, 0, pos);
-            final byte[] bytes = text.getBytes();
+            final byte[] bytes = text.getBytes(MurmurHash3.GET_BYTES_CHARSET);
             final int h1 = MurmurHash3.hash32(bytes, 0, bytes.length, seed);
             final int h2 = MurmurHash3.hash32(text);
             Assert.assertEquals(h1, h2);
@@ -455,7 +455,7 @@ public void testHash32x86WithTrailingNegativeSignedBytes() {
      */
     @Test
     public void testHash64() {
-        final byte[] origin = TEST_HASH64.getBytes();
+        final byte[] origin = TEST_HASH64.getBytes(MurmurHash3.GET_BYTES_CHARSET);
         final long hash = MurmurHash3.hash64(origin);
         Assert.assertEquals(5785358552565094607L, hash);
     }
@@ -466,7 +466,7 @@ public void testHash64() {
      */
     @Test
     public void testHash64WithOffsetAndLength() {
-        final byte[] origin = TEST_HASH64.getBytes();
+        final byte[] origin = TEST_HASH64.getBytes(MurmurHash3.GET_BYTES_CHARSET);
         final byte[] originOffset = new byte[origin.length + 150];
         Arrays.fill(originOffset, (byte) 123);
         System.arraycopy(origin, 0, originOffset, 150, origin.length);
@@ -627,7 +627,7 @@ public void testHash128String() {
                 pos += Character.toChars(codePoint, chars, pos);
             }
             final String text = String.copyValueOf(chars, 0, pos);
-            final byte[] bytes = text.getBytes();
+            final byte[] bytes = text.getBytes(MurmurHash3.GET_BYTES_CHARSET);
             final long[] h1 = MurmurHash3.hash128(bytes, 0, bytes.length, seed);
             final long[] h2 = MurmurHash3.hash128(text);
             Assert.assertArrayEquals(h1, h2);