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The following commit(s) were added to refs/heads/master by this push:
new b3eeb52f Add org.apache.commons.codec.digest.CRC16
b3eeb52f is described below
commit b3eeb52ff92165277a68f99366f4ff05f20c38a2
Author: Gary D. Gregory <[email protected]>
AuthorDate: Sun Aug 17 16:53:30 2025 -0400
Add org.apache.commons.codec.digest.CRC16
Extracted from https://github.com/apache/commons-compress/pull/690 and
modified
---
src/changes/changes.xml | 3 +-
.../org/apache/commons/codec/digest/CRC16.java | 201 +++++++++++++++++++++
.../org/apache/commons/codec/digest/CRC16Test.java | 98 ++++++++++
3 files changed, 301 insertions(+), 1 deletion(-)
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index e74e2553..6d329a05 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -43,9 +43,10 @@ The <action> type attribute can be add,update,fix,remove.
<author>Apache Commons Developers</author>
</properties>
<body>
- <release version="1.19.1" date="YYYY-MM-DD" description="This is a feature
and maintenance release. Java 8 or later is required.">
+ <release version="1.20.0" date="YYYY-MM-DD" description="This is a feature
and maintenance release. Java 8 or later is required.">
<!-- FIX -->
<!-- ADD -->
+ <action type="add" dev="ggregory" due-to="Fredrik Kjellberg, Gary
Gregory">Add org.apache.commons.codec.digest.CRC16.</action>
<!-- UPDATE -->
</release>
<release version="1.19.0" date="2025-07-19" description="This is a feature
and maintenance release. Java 8 or later is required.">
diff --git a/src/main/java/org/apache/commons/codec/digest/CRC16.java
b/src/main/java/org/apache/commons/codec/digest/CRC16.java
new file mode 100644
index 00000000..58cbe826
--- /dev/null
+++ b/src/main/java/org/apache/commons/codec/digest/CRC16.java
@@ -0,0 +1,201 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.codec.digest;
+
+import java.util.function.Supplier;
+import java.util.zip.Checksum;
+
+/**
+ * CRC-16 checksum implementation based on polynomial {@code x<sup>16</spu> +
x^15 + x^2 + 1 (0x8005)} and the initial value {@code 0x0000}. This CRC variant
is
+ * also known as CRC-16-MODBUS.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Cyclic_redundancy_check";>Cyclic
redundancy check</a>
+ * @see <a href="https://reveng.sourceforge.io/crc-catalogue/16.htm";>Catalogue
of parametrised CRC algorithms with 16 bits</a>
+ * @see <a href="https://www.lammertbies.nl/comm/info/crc-calculation";>On-line
CRC calculation and free library</a>
+ * @see <a
href="https://crccalc.com/?crc=123456789&method=&datatype=ascii&outtype=hex";>crccalc</a>
+ * @since 1.20.0
+ */
+public class CRC16 implements Checksum {
+
+ /**
+ * Builds CRC16 instances.
+ */
+ public static class Builder implements Supplier<CRC16> {
+
+ private int init = DEFAULT_INIT;
+ private int[] t = T_DEFAULT;
+
+ /**
+ * Constructs a new instance.
+ */
+ public Builder() {
+ // empty
+ }
+
+ /**
+ * Creates a new {@link CRC16} instance.
+ */
+ @Override
+ public CRC16 get() {
+ return new CRC16(this);
+ }
+
+ /**
+ * Sets the initial value.
+ *
+ * @param init the initial value.
+ * @return {@code this} instance.
+ */
+ public Builder setInit(final int init) {
+ this.init = init;
+ return this;
+ }
+
+ /**
+ * Sets the lookup table.
+ *
+ * @param t the lookup table, making a clone of the input array.
+ * @return {@code this} instance.
+ */
+ public Builder setTable(final int[] t) {
+ this.t = t != null ? t.clone() : T_DEFAULT;
+ return this;
+ }
+ }
+
+ private static final int DEFAULT_INIT = 0x0000;
+ // @formatter:off
+ private static final int[] T_MODBUS = {
+ 0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
+ 0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
+ 0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
+ 0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
+ 0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
+ 0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
+ 0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
+ 0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
+ 0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
+ 0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
+ 0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
+ 0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
+ 0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
+ 0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
+ 0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
+ 0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
+ 0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
+ 0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
+ 0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
+ 0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
+ 0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
+ 0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
+ 0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
+ 0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
+ 0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
+ 0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
+ 0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
+ 0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
+ 0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
+ 0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
+ 0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
+ 0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040
+ };
+
+ private static final int[] T_DEFAULT = T_MODBUS;
+
+ /**
+ * Creates a new builder.
+ *
+ * @return a new builder.
+ */
+ public static Builder builder() {
+ return new Builder();
+ }
+
+ /**
+ * Creates a new default CRC16.
+ *
+ * @return a new default CRC16.
+ */
+ public static CRC16 crc16() {
+ return builder().setInit(DEFAULT_INIT).setTable(T_DEFAULT).get();
+ }
+
+ /**
+ * Creates a new MODBUS CRC16.
+ *
+ * @return a new MODBUS CRC16.
+ */
+ public static CRC16 modbus() {
+ return builder().setInit(0xFFFF).setTable(T_MODBUS).get();
+ }
+
+ // @formatter:on
+ /**
+ * CRC.
+ */
+ private int crc;
+ private final int init;
+ private final int[] t;
+
+ /**
+ * Constructs a new instance.
+ */
+ public CRC16() {
+ this(builder());
+ }
+
+ /**
+ * Constructs a new instance.
+ */
+ private CRC16(final Builder builder) {
+ this.init = builder.init;
+ this.crc = builder.init;
+ this.t = builder.t;
+ }
+
+ /**
+ * Gets the init value.
+ *
+ * @return the init value.
+ */
+ int getInit() {
+ return init;
+ }
+
+ @Override
+ public long getValue() {
+ return crc;
+ }
+
+ @Override
+ public void reset() {
+ crc = init;
+ }
+
+ @Override
+ public void update(final byte[] b, final int off, final int len) {
+ for (int i = 0; i < len; i++) {
+ update(b[off + i]);
+ }
+ }
+
+ @Override
+ public void update(final int b) {
+ crc = crc >>> 8 ^ t[(crc ^ b) & 0xff];
+ }
+}
diff --git a/src/test/java/org/apache/commons/codec/digest/CRC16Test.java
b/src/test/java/org/apache/commons/codec/digest/CRC16Test.java
new file mode 100644
index 00000000..3393ead0
--- /dev/null
+++ b/src/test/java/org/apache/commons/codec/digest/CRC16Test.java
@@ -0,0 +1,98 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.codec.digest;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.nio.charset.StandardCharsets;
+import java.util.zip.Checksum;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests {@link CRC16}.
+ */
+class CRC16Test {
+
+ private static final byte[] BYTES_123456789 =
"123456789".getBytes(StandardCharsets.US_ASCII);
+
+ @Test
+ void testDefault() {
+ final Checksum crc16 = CRC16.crc16();
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0xBB3D, crc16.getValue());
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0xED7B, crc16.getValue());
+ crc16.reset();
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0xBB3D, crc16.getValue());
+ }
+
+ @Test
+ void testInit() {
+ final Checksum crc16 = CRC16.builder().setInit(0xFFFF).get();
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0x4B37, crc16.getValue());
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0x090A, crc16.getValue());
+ crc16.reset();
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0x4B37, crc16.getValue());
+ }
+
+ @Test
+ void testModbus() {
+ final Checksum crc16 = CRC16.modbus();
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0x4B37, crc16.getValue());
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0x090A, crc16.getValue());
+ crc16.reset();
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0x4B37, crc16.getValue());
+ }
+
+ @Test
+ void testReset() {
+ final Checksum crc16 = new CRC16();
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0xBB3D, crc16.getValue());
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0xED7B, crc16.getValue());
+ crc16.reset();
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0xbb3d, crc16.getValue());
+ }
+
+ @Test
+ void testUpdateArray() {
+ final Checksum crc16 = new CRC16();
+ crc16.update(BYTES_123456789, 0, 9);
+ assertEquals(0xBB3D, crc16.getValue());
+ }
+
+ @Test
+ void testUpdateInt() {
+ final Checksum crc16 = new CRC16();
+ final byte[] bytes = BYTES_123456789;
+ for (final byte element : bytes) {
+ crc16.update(element);
+ }
+ assertEquals(0xBB3D, crc16.getValue());
+ }
+}
