This is an automated email from the ASF dual-hosted git repository.
ggregory pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-compress.git
commit 8807948a5c47a715417f2f502511eeac6d624b29
Author: Gary Gregory <garydgreg...@gmail.com>
AuthorDate: Sat Nov 4 17:01:09 2023 -0400
Format
---
.../compressors/snappy/PureJavaCrc32C.java | 90 ++++++++++++----------
1 file changed, 51 insertions(+), 39 deletions(-)
diff --git
a/src/main/java/org/apache/commons/compress/compressors/snappy/PureJavaCrc32C.java
b/src/main/java/org/apache/commons/compress/compressors/snappy/PureJavaCrc32C.java
index d80806c7..25779913 100644
---
a/src/main/java/org/apache/commons/compress/compressors/snappy/PureJavaCrc32C.java
+++
b/src/main/java/org/apache/commons/compress/compressors/snappy/PureJavaCrc32C.java
@@ -23,11 +23,13 @@ package org.apache.commons.compress.compressors.snappy;
import java.util.zip.Checksum;
/**
- * A pure-java implementation of the CRC32 checksum that uses
- * the CRC32-C polynomial, the same polynomial used by iSCSI
- * and implemented on many Intel chipsets supporting SSE4.2.
+ * A pure-java implementation of the CRC32 checksum that uses the CRC32-C
polynomial, the same polynomial used by iSCSI and implemented on many Intel
chipsets
+ * supporting SSE4.2.
+ *
+ * <p>
+ * This file is a copy of the implementation at the Apache Hadoop project.
+ * </p>
*
- * <p>This file is a copy of the implementation at the Apache Hadoop
project.</p>
* @see
"https://svn.apache.org/repos/asf/hadoop/common/trunk/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/PureJavaCrc32C.java";
* @NotThreadSafe
* @since 1.7
@@ -574,65 +576,75 @@ final class PureJavaCrc32C implements Checksum {
0xE54C35A1, 0xAC704886, 0x7734CFEF, 0x3E08B2C8,
0xC451B7CC, 0x8D6DCAEB, 0x56294D82, 0x1F1530A5
};
+
/** the current CRC value, bit-flipped */
private int crc;
+
/** Create a new PureJavaCrc32 object. */
public PureJavaCrc32C() {
- reset(); // non-private, but the class is now final
+ reset(); // non-private, but the class is now final
}
+
@Override
public long getValue() {
- final long ret = crc;
- return ~ret & 0xffffffffL;
+ final long ret = crc;
+ return ~ret & 0xffffffffL;
}
+
@Override
// called by ctor but the class is final so this is safe
public void reset() {
- crc = 0xffffffff;
+ crc = 0xffffffff;
}
+
@Override
public void update(final byte[] b, int off, int len) {
- int localCrc = crc;
+ int localCrc = crc;
- while(len > 7) {
- final int c0 =(b[off+0] ^ localCrc) & 0xff;
- final int c1 =(b[off+1] ^ (localCrc >>>= 8)) & 0xff; //NOSONAR
- final int c2 =(b[off+2] ^ (localCrc >>>= 8)) & 0xff; //NOSONAR
- final int c3 =(b[off+3] ^ (localCrc >>>= 8)) & 0xff; //NOSONAR
- localCrc = T[T8_7_START + c0] ^ T[T8_6_START + c1]
- ^ T[T8_5_START + c2] ^ T[T8_4_START + c3];
+ while (len > 7) {
+ final int c0 = (b[off + 0] ^ localCrc) & 0xff;
+ final int c1 = (b[off + 1] ^ (localCrc >>>= 8)) & 0xff; // NOSONAR
+ final int c2 = (b[off + 2] ^ (localCrc >>>= 8)) & 0xff; // NOSONAR
+ final int c3 = (b[off + 3] ^ (localCrc >>>= 8)) & 0xff; // NOSONAR
+ localCrc = T[T8_7_START + c0] ^ T[T8_6_START + c1] ^ T[T8_5_START +
c2] ^ T[T8_4_START + c3];
- final int c4 = b[off+4] & 0xff;
- final int c5 = b[off+5] & 0xff;
- final int c6 = b[off+6] & 0xff;
- final int c7 = b[off+7] & 0xff;
+ final int c4 = b[off + 4] & 0xff;
+ final int c5 = b[off + 5] & 0xff;
+ final int c6 = b[off + 6] & 0xff;
+ final int c7 = b[off + 7] & 0xff;
- localCrc ^= T[T8_3_START + c4] ^ T[T8_2_START + c5]
- ^ T[T8_1_START + c6] ^ T[T8_0_START + c7];
+ localCrc ^= T[T8_3_START + c4] ^ T[T8_2_START + c5] ^ T[T8_1_START +
c6] ^ T[T8_0_START + c7];
- off += 8;
- len -= 8;
- }
+ off += 8;
+ len -= 8;
+ }
- /* loop unroll - duff's device style */
- switch(len) {
- case 7: localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^
b[off++]) & 0xff)];
- case 6: localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^
b[off++]) & 0xff)];
- case 5: localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^
b[off++]) & 0xff)];
- case 4: localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^
b[off++]) & 0xff)];
- case 3: localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^
b[off++]) & 0xff)];
- case 2: localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^
b[off++]) & 0xff)];
- case 1: localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^
b[off++]) & 0xff)];
+ /* loop unroll - duff's device style */
+ switch (len) {
+ case 7:
+ localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^ b[off++]) &
0xff)];
+ case 6:
+ localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^ b[off++]) &
0xff)];
+ case 5:
+ localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^ b[off++]) &
0xff)];
+ case 4:
+ localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^ b[off++]) &
0xff)];
+ case 3:
+ localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^ b[off++]) &
0xff)];
+ case 2:
+ localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^ b[off++]) &
0xff)];
+ case 1:
+ localCrc = localCrc >>> 8 ^ T[T8_0_START + ((localCrc ^ b[off++]) &
0xff)];
default:
- /* nothing */
- }
+ /* nothing */
+ }
- // Publish crc out to object
- crc = localCrc;
+ // Publish crc out to object
+ crc = localCrc;
}
@Override
public void update(final int b) {
- crc = crc >>> 8 ^ T[T8_0_START + ((crc ^ b) & 0xff)];
+ crc = crc >>> 8 ^ T[T8_0_START + ((crc ^ b) & 0xff)];
}
}
