support bytebuffer updates on streaming hashes

In some cases ByteBuffers do not provide access to an underlying
byte array without incurring copies, this is notably the case
for off-heap direct bytebuffers.

This patch provides a way to call update on streaming XXHASH instances
against a ByteBuffer, which avoids the extra copy needed into a byte
array.

src/build/source_templates/xxhash32_streaming.template

@@ -6,6 +6,7 @@ import static net.jpountz.xxhash.XXHashConstants.*;
 import static net.jpountz.util.${type}Utils.*;
 import static net.jpountz.util.SafeUtils.checkRange;
 import static java.lang.Integer.rotateLeft;
+import java.nio.ByteBuffer;
 
 /**
  * Streaming xxhash.
@@ -60,6 +61,11 @@ final class StreamingXXHash32Java${type} extends AbstractStreamingXXHash32Java {
     return h32;
   }
 
+  @Override
+  public void update(ByteBuffer buf, int off, int len) {
+    throw new RuntimeException("unimplemented");
+  }
+
   @Override
   public void update(byte[] buf, int off, int len) {
     checkRange(buf, off, len);
@@ -139,4 +145,3 @@ final class StreamingXXHash32Java${type} extends AbstractStreamingXXHash32Java {
   }
 
 }
-

src/build/source_templates/xxhash64_streaming.template

@@ -6,6 +6,7 @@ import static net.jpountz.xxhash.XXHashConstants.*;
 import static net.jpountz.util.${type}Utils.*;
 import static net.jpountz.util.SafeUtils.checkRange;
 import static java.lang.Long.rotateLeft;
+import java.nio.ByteBuffer;
 
 /**
  * Streaming xxhash.
@@ -84,6 +85,11 @@ final class StreamingXXHash64Java${type} extends AbstractStreamingXXHash64Java {
     return h64;
   }
 
+  @Override
+  public void update(ByteBuffer buf, int off, int len) {
+    throw new RuntimeException("unimplemented");
+  }
+
   @Override
   public void update(byte[] buf, int off, int len) {
     checkRange(buf, off, len);
@@ -163,4 +169,3 @@ final class StreamingXXHash64Java${type} extends AbstractStreamingXXHash64Java {
   }
 
 }
-

src/java/net/jpountz/xxhash/StreamingXXHash32.java

@@ -2,6 +2,7 @@
 
 import java.util.zip.Checksum;
 import java.io.Closeable;
+import java.nio.ByteBuffer;
 
 /*
  * Copyright 2020 Adrien Grand and the lz4-java contributors.
@@ -71,6 +72,15 @@ interface Factory {
    */
   public abstract void update(byte[] buf, int off, int len);
 
+  /**
+   * Updates the value of the hash with buf[off:off+len].
+   *
+   * @param buf the input data
+   * @param off the start offset in buf
+   * @param len the number of bytes to hash
+   */
+  public abstract void update(ByteBuffer buf, int off, int len);
+
   /**
    * Resets this instance to the state it had right after instantiation. The
    * seed remains unchanged.

src/java/net/jpountz/xxhash/StreamingXXHash32JNI.java

@@ -1,5 +1,7 @@
 package net.jpountz.xxhash;
 
+import java.nio.ByteBuffer;
+
 /*
  * Copyright 2020 Adrien Grand and the lz4-java contributors.
  *
@@ -69,6 +71,11 @@ public synchronized void update(byte[] bytes, int off, int len) {
     XXHashJNI.XXH32_update(state, bytes, off, len);
   }
 
+  public synchronized void update(ByteBuffer buf, int off, int len) {
+    checkState();
+    XXHashJNI.XXH32BB_update(state, buf, off, len);
+  }
+
   @Override
   public synchronized void close() {
     if (state != 0) {

src/java/net/jpountz/xxhash/StreamingXXHash64.java

@@ -1,6 +1,7 @@
 package net.jpountz.xxhash;
 
 import java.util.zip.Checksum;
+import java.nio.ByteBuffer;
 import java.io.Closeable;
 
 /*
@@ -71,6 +72,15 @@ interface Factory {
    */
   public abstract void update(byte[] buf, int off, int len);
 
+  /**
+   * Updates the value of the hash with buf[off:off+len].
+   *
+   * @param buf the input data
+   * @param off the start offset in buf
+   * @param len the number of bytes to hash
+   */
+  public abstract void update(ByteBuffer buf, int off, int len);
+
   /**
    * Resets this instance to the state it had right after instantiation. The
    * seed remains unchanged.

src/java/net/jpountz/xxhash/StreamingXXHash64JNI.java

@@ -1,5 +1,7 @@
 package net.jpountz.xxhash;
 
+import java.nio.ByteBuffer;
+
 /*
  * Copyright 2020 Linnaea Von Lavia and the lz4-java contributors.
  *
@@ -70,6 +72,12 @@ public synchronized void update(byte[] bytes, int off, int len) {
     XXHashJNI.XXH64_update(state, bytes, off, len);
   }
 
+  @Override
+  public synchronized void update(ByteBuffer buf, int off, int len) {
+    checkState();
+    XXHashJNI.XXH64BB_update(state, buf, off, len);
+  }
+
   @Override
   public synchronized void close() {
     if (state != 0) {

src/java/net/jpountz/xxhash/XXHashJNI.java

@@ -33,13 +33,15 @@ enum XXHashJNI {
   static native int XXH32BB(ByteBuffer input, int offset, int len, int seed);
   static native long XXH32_init(int seed);
   static native void XXH32_update(long state, byte[] input, int offset, int len);
+  static native void XXH32BB_update(long state, ByteBuffer input, int offset, int len);
   static native int XXH32_digest(long state);
   static native void XXH32_free(long state);
 
   static native long XXH64(byte[] input, int offset, int len, long seed);
   static native long XXH64BB(ByteBuffer input, int offset, int len, long seed);
   static native long XXH64_init(long seed);
   static native void XXH64_update(long state, byte[] input, int offset, int len);
+  static native void XXH64BB_update(long state, ByteBuffer input, int offset, int len);
   static native long XXH64_digest(long state);
   static native void XXH64_free(long state);
 }

src/jni/net_jpountz_xxhash_XXHashJNI.c

@@ -120,6 +120,26 @@ JNIEXPORT void JNICALL Java_net_jpountz_xxhash_XXHashJNI_XXH32_1update
 
 }
 
+/*
+ * Class:     net_jpountz_xxhash_XXHashJNI
+ * Method:    XXH32BB_update
+ * Signature: (JLjava/nio/ByteBuffer;II)V
+ */
+JNIEXPORT void JNICALL Java_net_jpountz_xxhash_XXHashJNI_XXH32BB_1update
+(JNIEnv *env, jclass cls, jlong state, jbyteArray src, jint off, jint len) {
+
+  char* in;
+  jlong h64;
+
+  in = (char*) (*env)->GetDirectBufferAddress(env, src);
+  if (in == NULL) {
+    throw_OOM(env);
+    return;
+  }
+
+  XXH32_update((XXH32_state_t*) state, in + off, len);
+}
+
 /*
  * Class:     net_jpountz_xxhash_XXHashJNI
  * Method:    XXH32_digest
@@ -230,6 +250,26 @@ JNIEXPORT void JNICALL Java_net_jpountz_xxhash_XXHashJNI_XXH64_1update
 
 }
 
+/*
+ * Class:     net_jpountz_xxhash_XXHashJNI
+ * Method:    XXH64BB_update
+ * Signature: (JLjava/nio/ByteBuffer;II)V
+ */
+JNIEXPORT void JNICALL Java_net_jpountz_xxhash_XXHashJNI_XXH64BB_1update
+(JNIEnv *env, jclass cls, jlong state, jbyteArray src, jint off, jint len) {
+
+  char* in;
+  jlong h64;
+
+  in = (char*) (*env)->GetDirectBufferAddress(env, src);
+  if (in == NULL) {
+    throw_OOM(env);
+    return;
+  }
+
+  XXH64_update((XXH64_state_t*) state, in + off, len);
+}
+
 /*
  * Class:     net_jpountz_xxhash_XXHashJNI
  * Method:    XXH64_digest