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Posted to commits@commons.apache.org by ah...@apache.org on 2019/11/21 17:38:49 UTC
[commons-codec] branch master updated (03e5497 -> 5204e89)
This is an automated email from the ASF dual-hosted git repository.
aherbert pushed a change to branch master
in repository https://gitbox.apache.org/repos/asf/commons-codec.git.
from 03e5497 Added @since 1.14 to MurmurHash3 additions.
new 31e094a Javadoc clean-up.
new 5204e89 Moved magic numbers to constants.
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repository and will be described in separate emails. The revisions
listed as "add" were already present in the repository and have only
been added to this reference.
Summary of changes:
.../apache/commons/codec/digest/MurmurHash2.java | 118 ++++++++++-----------
1 file changed, 59 insertions(+), 59 deletions(-)
[commons-codec] 01/02: Javadoc clean-up.
Posted by ah...@apache.org.
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 31e094ab90d238cfbd98b9ed8c715d997f58123a
Author: aherbert <ah...@apache.org>
AuthorDate: Thu Nov 21 17:36:22 2019 +0000
Javadoc clean-up.
Removed 'offset' from javadoc examples.
Change 32 bit to 32-bit.
Change 64 bit to 64-bit.
Change descriptions to match those in MurmurHash3.
---
.../apache/commons/codec/digest/MurmurHash2.java | 72 +++++++++++-----------
1 file changed, 36 insertions(+), 36 deletions(-)
diff --git a/src/main/java/org/apache/commons/codec/digest/MurmurHash2.java b/src/main/java/org/apache/commons/codec/digest/MurmurHash2.java
index e349ff9..abf0cfc 100644
--- a/src/main/java/org/apache/commons/codec/digest/MurmurHash2.java
+++ b/src/main/java/org/apache/commons/codec/digest/MurmurHash2.java
@@ -53,12 +53,12 @@ public final class MurmurHash2 {
}
/**
- * Generates 32 bit hash from byte array with the given length and seed.
+ * Generates a 32-bit hash from byte array with the given length and seed.
*
- * @param data byte array to hash
- * @param length length of the array to hash
- * @param seed initial seed value
- * @return 32 bit hash of the given array
+ * @param data The input byte array
+ * @param length The length of the array
+ * @param seed The initial seed value
+ * @return The 32-bit hash
*/
public static int hash32(final byte[] data, final int length, final int seed) {
// 'm' and 'r' are mixing constants generated offline.
@@ -105,17 +105,17 @@ public final class MurmurHash2 {
}
/**
- * Generates 32 bit hash from byte array with the given length and a default seed value.
+ * Generates a 32-bit hash from byte array with the given length and a default seed value.
* This is a helper method that will produce the same result as:
*
* <pre>
* int seed = 0x9747b28c;
- * int hash = MurmurHash2.hash32(data, offset, length, seed);
+ * int hash = MurmurHash2.hash32(data, length, seed);
* </pre>
*
- * @param data byte array to hash
- * @param length length of the array to hash
- * @return 32 bit hash of the given array
+ * @param data The input byte array
+ * @param length The length of the array
+ * @return The 32-bit hash
* @see #hash32(byte[], int, int)
*/
public static int hash32(final byte[] data, final int length) {
@@ -123,7 +123,7 @@ public final class MurmurHash2 {
}
/**
- * Generates 32 bit hash from a string with a default seed.
+ * Generates a 32-bit hash from a string with a default seed.
* The string is converted to bytes using the default encoding.
* This is a helper method that will produce the same result as:
*
@@ -133,8 +133,8 @@ public final class MurmurHash2 {
* int hash = MurmurHash2.hash32(bytes, bytes.length, seed);
* </pre>
*
- * @param text string to hash
- * @return 32 bit hash of the given string
+ * @param text The input string
+ * @return The 32-bit hash
* @see #hash32(byte[], int, int)
*/
public static int hash32(final String text) {
@@ -143,7 +143,7 @@ public final class MurmurHash2 {
}
/**
- * Generates 32 bit hash from a substring with a default seed value.
+ * Generates a 32-bit hash from a substring with a default seed value.
* The string is converted to bytes using the default encoding.
* This is a helper method that will produce the same result as:
*
@@ -153,10 +153,10 @@ public final class MurmurHash2 {
* int hash = MurmurHash2.hash32(bytes, bytes.length, seed);
* </pre>
*
- * @param text string to hash
- * @param from starting index
- * @param length length of the substring to hash
- * @return 32 bit hash of the given string
+ * @param text The input string
+ * @param from The starting index
+ * @param length The length of the substring
+ * @return The 32-bit hash
* @see #hash32(byte[], int, int)
*/
public static int hash32(final String text, final int from, final int length) {
@@ -164,12 +164,12 @@ public final class MurmurHash2 {
}
/**
- * Generates 64 bit hash from byte array of the given length and seed.
+ * Generates a 64-bit hash from byte array of the given length and seed.
*
- * @param data byte array to hash
- * @param length length of the array to hash
- * @param seed initial seed value
- * @return 64 bit hash of the given array
+ * @param data The input byte array
+ * @param length The length of the array
+ * @param seed The initial seed value
+ * @return The 64-bit hash of the given array
*/
public static long hash64(final byte[] data, final int length, final int seed) {
final long m = 0xc6a4a7935bd1e995L;
@@ -219,17 +219,17 @@ public final class MurmurHash2 {
}
/**
- * Generates 64 bit hash from byte array with given length and a default seed value.
+ * Generates a 64-bit hash from byte array with given length and a default seed value.
* This is a helper method that will produce the same result as:
*
* <pre>
* int seed = 0xe17a1465;
- * int hash = MurmurHash2.hash64(data, offset, length, seed);
+ * int hash = MurmurHash2.hash64(data, length, seed);
* </pre>
*
- * @param data byte array to hash
- * @param length length of the array to hash
- * @return 64 bit hash of the given string
+ * @param data The input byte array
+ * @param length The length of the array
+ * @return The 64-bit hash
* @see #hash64(byte[], int, int)
*/
public static long hash64(final byte[] data, final int length) {
@@ -237,7 +237,7 @@ public final class MurmurHash2 {
}
/**
- * Generates 64 bit hash from a string with a default seed.
+ * Generates a 64-bit hash from a string with a default seed.
* The string is converted to bytes using the default encoding.
* This is a helper method that will produce the same result as:
*
@@ -247,8 +247,8 @@ public final class MurmurHash2 {
* int hash = MurmurHash2.hash64(bytes, bytes.length, seed);
* </pre>
*
- * @param text string to hash
- * @return 64 bit hash of the given string
+ * @param text The input string
+ * @return The 64-bit hash
* @see #hash64(byte[], int, int)
*/
public static long hash64(final String text) {
@@ -257,7 +257,7 @@ public final class MurmurHash2 {
}
/**
- * Generates 64 bit hash from a substring with a default seed value.
+ * Generates a 64-bit hash from a substring with a default seed value.
* The string is converted to bytes using the default encoding.
* This is a helper method that will produce the same result as:
*
@@ -267,10 +267,10 @@ public final class MurmurHash2 {
* int hash = MurmurHash2.hash64(bytes, bytes.length, seed);
* </pre>
*
- * @param text string to hash
- * @param from starting index
- * @param length length of the substring to hash
- * @return 64 bit hash of the given array
+ * @param text The The input string
+ * @param from The starting index
+ * @param length The length of the substring
+ * @return The 64-bit hash
* @see #hash64(byte[], int, int)
*/
public static long hash64(final String text, final int from, final int length) {
[commons-codec] 02/02: Moved magic numbers to constants.
Posted by ah...@apache.org.
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 5204e89987d2cb9de75207226f97452578eb024f
Author: aherbert <ah...@apache.org>
AuthorDate: Thu Nov 21 17:38:45 2019 +0000
Moved magic numbers to constants.
---
.../apache/commons/codec/digest/MurmurHash2.java | 46 +++++++++++-----------
1 file changed, 23 insertions(+), 23 deletions(-)
diff --git a/src/main/java/org/apache/commons/codec/digest/MurmurHash2.java b/src/main/java/org/apache/commons/codec/digest/MurmurHash2.java
index abf0cfc..bbbb142 100644
--- a/src/main/java/org/apache/commons/codec/digest/MurmurHash2.java
+++ b/src/main/java/org/apache/commons/codec/digest/MurmurHash2.java
@@ -48,6 +48,14 @@ package org.apache.commons.codec.digest;
*/
public final class MurmurHash2 {
+ // Constants for 32-bit variant
+ private static final int M32 = 0x5bd1e995;
+ private static final int R32 = 24;
+
+ // Constants for 64-bit variant
+ private static final long M64 = 0xc6a4a7935bd1e995L;
+ private static final int R64 = 47;
+
/** No instance methods. */
private MurmurHash2() {
}
@@ -61,11 +69,6 @@ public final class MurmurHash2 {
* @return The 32-bit hash
*/
public static int hash32(final byte[] data, final int length, final int seed) {
- // 'm' and 'r' are mixing constants generated offline.
- // They're not really 'magic', they just happen to work well.
- final int m = 0x5bd1e995;
- final int r = 24;
-
// Initialize the hash to a random value
int h = seed ^ length;
@@ -76,10 +79,10 @@ public final class MurmurHash2 {
for (int i = 0; i < nblocks; i++) {
final int index = (i << 2);
int k = getLittleEndianInt(data, index);
- k *= m;
- k ^= k >>> r;
- k *= m;
- h *= m;
+ k *= M32;
+ k ^= k >>> R32;
+ k *= M32;
+ h *= M32;
h ^= k;
}
@@ -92,13 +95,13 @@ public final class MurmurHash2 {
h ^= (data[index + 1] & 0xff) << 8;
case 1:
h ^= (data[index] & 0xff);
- h *= m;
+ h *= M32;
}
// Do a few final mixes of the hash to ensure the last few
// bytes are well-incorporated.
h ^= h >>> 13;
- h *= m;
+ h *= M32;
h ^= h >>> 15;
return h;
@@ -172,10 +175,7 @@ public final class MurmurHash2 {
* @return The 64-bit hash of the given array
*/
public static long hash64(final byte[] data, final int length, final int seed) {
- final long m = 0xc6a4a7935bd1e995L;
- final int r = 47;
-
- long h = (seed & 0xffffffffl) ^ (length * m);
+ long h = (seed & 0xffffffffL) ^ (length * M64);
final int nblocks = length >> 3;
@@ -184,12 +184,12 @@ public final class MurmurHash2 {
final int index = (i << 3);
long k = getLittleEndianLong(data, index);
- k *= m;
- k ^= k >>> r;
- k *= m;
+ k *= M64;
+ k ^= k >>> R64;
+ k *= M64;
h ^= k;
- h *= m;
+ h *= M64;
}
final int index = (nblocks << 3);
@@ -208,12 +208,12 @@ public final class MurmurHash2 {
h ^= ((long) data[index + 1] & 0xff) << 8;
case 1:
h ^= ((long) data[index] & 0xff);
- h *= m;
+ h *= M64;
}
- h ^= h >>> r;
- h *= m;
- h ^= h >>> r;
+ h ^= h >>> R64;
+ h *= M64;
+ h ^= h >>> R64;
return h;
}