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Posted to commits@commons.apache.org by ah...@apache.org on 2019/12/03 11:38:21 UTC
[commons-codec] 01/07: [CODEC-268] Deprecate MurmurHash4.hash64
This is an automated email from the ASF dual-hosted git repository.
aherbert pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-codec.git
commit df4a27c9b87d7d2afec56492f96c7e549a32fbf5
Author: aherbert <ah...@apache.org>
AuthorDate: Tue Dec 3 11:12:52 2019 +0000
[CODEC-268] Deprecate MurmurHash4.hash64
This is not part of the MurmurHash3 implementation. It was ported from
Apache Hive. The hash collision properties are unknown for this method.
Updated the javadoc to make it clear that the method does not return a
hash that matches either part of the 128-bit hash function.
---
.../apache/commons/codec/digest/MurmurHash3.java | 64 +++++++++++++++++-----
1 file changed, 50 insertions(+), 14 deletions(-)
diff --git a/src/main/java/org/apache/commons/codec/digest/MurmurHash3.java b/src/main/java/org/apache/commons/codec/digest/MurmurHash3.java
index bbedbf0..a1a03d7 100644
--- a/src/main/java/org/apache/commons/codec/digest/MurmurHash3.java
+++ b/src/main/java/org/apache/commons/codec/digest/MurmurHash3.java
@@ -39,7 +39,9 @@ package org.apache.commons.codec.digest;
* </blockquote>
*
* <p>Original adaption from Apache Hive. That adaption contains a {@code hash64} method
- * that is not part of the original MurmurHash3 code.<p>
+ * that is not part of the original MurmurHash3 code. It is not recommended to use these methods.
+ * They will be removed in a future release. To obtain a 64-bit hash use half of the bits
+ * from the {@code hash128x64} methods using the input data converted to bytes.<p>
*
* @see <a href="https://en.wikipedia.org/wiki/MurmurHash">MurmurHash</a>
* @see <a href="https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp">
@@ -428,9 +430,12 @@ public final class MurmurHash3 {
/**
* Generates 64-bit hash from a long with a default seed.
*
+ * <p><strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong></p>
+ *
* <p>This is a Murmur3-like 64-bit variant.
- * <strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong>
- * It may be removed in a future release.</p>
+ * The method does not produce the same result as either half of the hash bytes from
+ * {@linkplain #hash128x64(byte[])} with the same byte data from the {@code long}.
+ * This method will be removed in a future release.</p>
*
* <p>This is a helper method that will produce the same result as:</p>
*
@@ -445,7 +450,10 @@ public final class MurmurHash3 {
* @param data The long to hash
* @return The 64-bit hash
* @see #hash64(byte[], int, int, int)
+ * @deprecated Not part of the MurmurHash3 implementation.
+ * Use half of the hash bytes from {@link #hash128x64(byte[])} with the bytes from the {@code long}.
*/
+ @Deprecated
public static long hash64(final long data) {
long hash = DEFAULT_SEED;
long k = Long.reverseBytes(data);
@@ -465,9 +473,12 @@ public final class MurmurHash3 {
/**
* Generates 64-bit hash from an int with a default seed.
*
+ * <p><strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong></p>
+ *
* <p>This is a Murmur3-like 64-bit variant.
- * <strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong>
- * It may be removed in a future release.</p>
+ * The method does not produce the same result as either half of the hash bytes from
+ * {@linkplain #hash128x64(byte[])} with the same byte data from the {@code int}.
+ * This method will be removed in a future release.</p>
*
* <p>This is a helper method that will produce the same result as:</p>
*
@@ -482,7 +493,10 @@ public final class MurmurHash3 {
* @param data The int to hash
* @return The 64-bit hash
* @see #hash64(byte[], int, int, int)
+ * @deprecated Not part of the MurmurHash3 implementation.
+ * Use half of the hash bytes from {@link #hash128x64(byte[])} with the bytes from the {@code int}.
*/
+ @Deprecated
public static long hash64(final int data) {
long k1 = Integer.reverseBytes(data) & (-1L >>> 32);
final int length = INTEGER_BYTES;
@@ -500,9 +514,12 @@ public final class MurmurHash3 {
/**
* Generates 64-bit hash from a short with a default seed.
*
+ * <p><strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong></p>
+ *
* <p>This is a Murmur3-like 64-bit variant.
- * <strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong>
- * It may be removed in a future release.</p>
+ * The method does not produce the same result as either half of the hash bytes from
+ * {@linkplain #hash128x64(byte[])} with the same byte data from the {@code short}.
+ * This method will be removed in a future release.</p>
*
* <p>This is a helper method that will produce the same result as:</p>
*
@@ -517,7 +534,10 @@ public final class MurmurHash3 {
* @param data The short to hash
* @return The 64-bit hash
* @see #hash64(byte[], int, int, int)
+ * @deprecated Not part of the MurmurHash3 implementation.
+ * Use half of the hash bytes from {@link #hash128x64(byte[])} with the bytes from the {@code short}.
*/
+ @Deprecated
public static long hash64(final short data) {
long hash = DEFAULT_SEED;
long k1 = 0;
@@ -537,9 +557,12 @@ public final class MurmurHash3 {
/**
* Generates 64-bit hash from a byte array with a default seed.
*
+ * <p><strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong></p>
+ *
* <p>This is a Murmur3-like 64-bit variant.
- * <strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong>
- * It may be removed in a future release.</p>
+ * The method does not produce the same result as either half of the hash bytes from
+ * {@linkplain #hash128x64(byte[])} with the same byte data.
+ * This method will be removed in a future release.</p>
*
* <p>This is a helper method that will produce the same result as:</p>
*
@@ -552,7 +575,10 @@ public final class MurmurHash3 {
* @param data The input byte array
* @return The 64-bit hash
* @see #hash64(byte[], int, int, int)
+ * @deprecated Not part of the MurmurHash3 implementation.
+ * Use half of the hash bytes from {@link #hash128x64(byte[])}.
*/
+ @Deprecated
public static long hash64(final byte[] data) {
return hash64(data, 0, data.length, DEFAULT_SEED);
}
@@ -560,9 +586,12 @@ public final class MurmurHash3 {
/**
* Generates 64-bit hash from a byte array with the given offset and length and a default seed.
*
+ * <p><strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong></p>
+ *
* <p>This is a Murmur3-like 64-bit variant.
- * <strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong>
- * It may be removed in a future release.</p>
+ * The method does not produce the same result as either half of the hash bytes from
+ * {@linkplain #hash128x64(byte[])} with the same byte data.
+ * This method will be removed in a future release.</p>
*
* <p>This is a helper method that will produce the same result as:</p>
*
@@ -576,7 +605,10 @@ public final class MurmurHash3 {
* @param length The length of array
* @return The 64-bit hash
* @see #hash64(byte[], int, int, int)
+ * @deprecated Not part of the MurmurHash3 implementation.
+ * Use half of the hash bytes from {@link #hash128x64(byte[], int, int, int)}.
*/
+ @Deprecated
public static long hash64(final byte[] data, final int offset, final int length) {
return hash64(data, offset, length, DEFAULT_SEED);
}
@@ -584,9 +616,10 @@ public final class MurmurHash3 {
/**
* Generates 64-bit hash from a byte array with the given offset, length and seed.
*
+ * <p><strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong></p>
+ *
* <p>This is a Murmur3-like 64-bit variant.
- * <strong>This is not part of the original MurmurHash3 {@code c++} implementation.</strong>
- * It may be removed in a future release.</p>
+ * This method will be removed in a future release.</p>
*
* <p>This algorithm processes 8 bytes chunks of data in a manner similar to the 16 byte chunks
* of data processed in the MurmurHash3 {@code MurmurHash3_x64_128} method. However the hash
@@ -602,7 +635,10 @@ public final class MurmurHash3 {
* @param length The length of array
* @param seed The initial seed value
* @return The 64-bit hash
+ * @deprecated Not part of the MurmurHash3 implementation.
+ * Use half of the hash bytes from {@link #hash128x64(byte[], int, int, int)}.
*/
+ @Deprecated
public static long hash64(final byte[] data, final int offset, final int length, final int seed) {
// ************
// Note: This fails to apply masking using 0xffffffffL to the seed.
@@ -961,7 +997,7 @@ public final class MurmurHash3 {
/** The total number of input bytes added since the start. */
private int totalLen;
/**
- * The current running hash.
+ * The current running hash.
* This must be finalised to generate the 32-bit hash value.
*/
private int hash;