Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.lz4 / src / net / jpountz / xxhash / StreamingXXHash32.java

diff --git a/bundles/org.simantics.lz4/src/net/jpountz/xxhash/StreamingXXHash32.java b/bundles/org.simantics.lz4/src/net/jpountz/xxhash/StreamingXXHash32.java
new file mode 100644 (file)
index 0000000..c59f034
--- /dev/null
+++ b/bundles/org.simantics.lz4/src/net/jpountz/xxhash/StreamingXXHash32.java
@@ -0,0 +1,111 @@
+package net.jpountz.xxhash;
+
+import java.util.zip.Checksum;
+
+/*
+ * Licensed 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
+ *
+ *     http://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.
+ */
+
+
+
+/**
+ * Streaming interface for {@link XXHash32}.
+ * <p>
+ * This API is compatible with the {@link XXHash32 block API} and the following
+ * code samples are equivalent:
+ * <pre class="prettyprint">
+ *   int hash(XXHashFactory xxhashFactory, byte[] buf, int off, int len, int seed) {
+ *     return xxhashFactory.hash32().hash(buf, off, len, seed);
+ *   }
+ * </pre>
+ * <pre class="prettyprint">
+ *   int hash(XXHashFactory xxhashFactory, byte[] buf, int off, int len, int seed) {
+ *     StreamingXXHash32 sh32 = xxhashFactory.newStreamingHash32(seed);
+ *     sh32.update(buf, off, len);
+ *     return sh32.getValue();
+ *   }
+ * </pre>
+ * <p>
+ * Instances of this class are <b>not</b> thread-safe.
+ */
+public abstract class StreamingXXHash32 {
+
+  interface Factory {
+
+    StreamingXXHash32 newStreamingHash(int seed);
+
+  }
+
+  final int seed;
+
+  StreamingXXHash32(int seed) {
+    this.seed = seed;
+  }
+
+  /**
+   * Get the value of the checksum.
+   */
+  public abstract int getValue();
+
+  /**
+   * Update the value of the hash with buf[off:off+len].
+   */
+  public abstract void update(byte[] buf, int off, int len);
+
+  /**
+   * Reset this instance to the state it had right after instantiation. The
+   * seed remains unchanged.
+   */
+  public abstract void reset();
+
+  @Override
+  public String toString() {
+    return getClass().getSimpleName() + "(seed=" + seed + ")";
+  }
+
+  /**
+   * Return a {@link Checksum} view of this instance. Modifications to the view
+   * will modify this instance too and vice-versa.
+   */
+  public final Checksum asChecksum() {
+    return new Checksum() {
+
+      @Override
+      public long getValue() {
+        return StreamingXXHash32.this.getValue() & 0xFFFFFFFL;
+      }
+
+      @Override
+      public void reset() {
+        StreamingXXHash32.this.reset();
+      }
+
+      @Override
+      public void update(int b) {
+        StreamingXXHash32.this.update(new byte[] {(byte) b}, 0, 1);
+      }
+
+      @Override
+      public void update(byte[] b, int off, int len) {
+        StreamingXXHash32.this.update(b, off, len);
+      }
+
+      @Override
+      public String toString() {
+        return StreamingXXHash32.this.toString();
+      }
+
+    };
+  }
+
+}
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