Add handle bloomfilter entry this will handle when the scanner find none
model id broadcast
Test: entry no test
Bug: 214495869
Change-Id: I3b9def55b3aac553542493b053e8f51b6340e99b
diff --git a/nearby/service/java/com/android/server/nearby/common/bloomfilter/BloomFilter.java b/nearby/service/java/com/android/server/nearby/common/bloomfilter/BloomFilter.java
new file mode 100644
index 0000000..6d4275f
--- /dev/null
+++ b/nearby/service/java/com/android/server/nearby/common/bloomfilter/BloomFilter.java
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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.
+ */
+
+package com.android.server.nearby.common.bloomfilter;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.google.common.primitives.UnsignedInts;
+
+import java.nio.charset.Charset;
+import java.util.Arrays;
+import java.util.BitSet;
+
+/**
+ * A bloom filter that gives access to the underlying BitSet.
+ */
+public class BloomFilter {
+ private static final Charset CHARSET = UTF_8;
+
+ /**
+ * Receives a value and converts it into an array of ints that will be converted to indexes for
+ * the filter.
+ */
+ public interface Hasher {
+ /**
+ * Generate hash value.
+ */
+ int[] getHashes(byte[] value);
+ }
+
+ // The backing data for this bloom filter. As additions are made, they're OR'd until it
+ // eventually reaches 0xFF.
+ private final BitSet mBits;
+ // The max length of bits.
+ private final int mBitLength;
+ // The hasher to use for converting a value into an array of hashes.
+ private final Hasher mHasher;
+
+ public BloomFilter(byte[] bytes, Hasher hasher) {
+ this.mBits = BitSet.valueOf(bytes);
+ this.mBitLength = bytes.length * 8;
+ this.mHasher = hasher;
+ }
+
+ /**
+ * Return the bloom filter check bit set as byte array.
+ */
+ public byte[] asBytes() {
+ // BitSet.toByteArray() truncates all the unset bits after the last set bit (eg. [0,0,1,0]
+ // becomes [0,0,1]) so we re-add those bytes if needed with Arrays.copy().
+ byte[] b = mBits.toByteArray();
+ if (b.length == mBitLength / 8) {
+ return b;
+ }
+ return Arrays.copyOf(b, mBitLength / 8);
+ }
+
+ /**
+ * Add string value to bloom filter hash.
+ */
+ public void add(String s) {
+ add(s.getBytes(CHARSET));
+ }
+
+ /**
+ * Adds value to bloom filter hash.
+ */
+ public void add(byte[] value) {
+ int[] hashes = mHasher.getHashes(value);
+ for (int hash : hashes) {
+ mBits.set(UnsignedInts.remainder(hash, mBitLength));
+ }
+ }
+
+ /**
+ * Check if the string format has collision.
+ */
+ public boolean possiblyContains(String s) {
+ return possiblyContains(s.getBytes(CHARSET));
+ }
+
+ /**
+ * Checks if value after hash will have collision.
+ */
+ public boolean possiblyContains(byte[] value) {
+ int[] hashes = mHasher.getHashes(value);
+ for (int hash : hashes) {
+ if (!mBits.get(UnsignedInts.remainder(hash, mBitLength))) {
+ return false;
+ }
+ }
+ return true;
+ }
+}
+
diff --git a/nearby/service/java/com/android/server/nearby/provider/FastPairDataProvider.java b/nearby/service/java/com/android/server/nearby/provider/FastPairDataProvider.java
index 5c57ddf..9bf2bef 100644
--- a/nearby/service/java/com/android/server/nearby/provider/FastPairDataProvider.java
+++ b/nearby/service/java/com/android/server/nearby/provider/FastPairDataProvider.java
@@ -20,10 +20,12 @@
import android.annotation.Nullable;
import android.content.Context;
import android.nearby.FastPairDataProviderBase;
+import android.nearby.FastPairDevice;
import android.util.Log;
import androidx.annotation.WorkerThread;
+import com.android.server.nearby.common.bloomfilter.BloomFilter;
import com.android.server.nearby.fastpair.footprint.FastPairUploadInfo;
import service.proto.Rpcs;
@@ -90,4 +92,11 @@
}
+ /**
+ * Get recognized device from bloom filter.
+ */
+ public FastPairDevice getRecognizedDevice(BloomFilter bloomFilter, byte[] salt) {
+ return new FastPairDevice.Builder().build();
+ }
+
}