Remove short conversions in MapBuffer

Summary:
MapBuffer uses unsigned short in C++, but Java doesn't really have a type that represents that. That means that MapBuffer would be limited to max 32768 values instead of 65536, which doesn't make much sense as a limitation.
Considering weird (and usually not performant) handling of short values in Java in general, this change replaces them with ints, converting keys from short when needed with `key & 0xFFFF`.

Changelog: [Internal]

Reviewed By: javache

Differential Revision: D33595308

fbshipit-source-id: a7adde8a207bb4aa1d81d367ab5d7b41ace2e291

ReactAndroid/src/main/java/com/facebook/react/common/mapbuffer/ReadableMapBuffer.java

@@ -39,21 +39,10 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
 
   private static final int INT_SIZE = 4;
 
-  // TODO T83483191: consider moving short to INTs, we are doing extra cast operations just because
-  //  of short java operates with int
-  private static final int SHORT_SIZE = 2;
-
-  private static final short SHORT_ONE = (short) 1;
-
   @Nullable ByteBuffer mBuffer = null;
 
-  // Size of the Serialized Data
-  @SuppressWarnings("unused")
-  private int mSizeOfData = 0;
-
   // Amount of items serialized on the ByteBuffer
-  @SuppressWarnings("unused")
-  private short mCount = 0;
+  private int mCount = 0;
 
   @DoNotStrip
   private ReadableMapBuffer(HybridData hybridData) {
@@ -72,11 +61,11 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
   @Nullable
   private HybridData mHybridData;
 
-  private int getKeyOffsetForBucketIndex(int bucketIndex) {
+  private static int getKeyOffsetForBucketIndex(int bucketIndex) {
     return HEADER_SIZE + BUCKET_SIZE * bucketIndex;
   }
 
-  private int getValueOffsetForKey(short key) {
+  private int getValueOffsetForKey(int key) {
     importByteBufferAndReadHeader();
     int bucketIndex = getBucketIndexForKey(key);
     if (bucketIndex == -1) {
@@ -98,16 +87,16 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
    * @return the "bucket index" for a key or -1 if not found. It uses a binary search algorithm
    *     (log(n))
    */
-  private int getBucketIndexForKey(short key) {
-    short lo = 0;
-    short hi = (short) (getCount() - SHORT_ONE);
+  private int getBucketIndexForKey(int key) {
+    int lo = 0;
+    int hi = getCount() - 1;
     while (lo <= hi) {
-      final short mid = (short) ((lo + hi) >>> SHORT_ONE);
-      final short midVal = readKey(getKeyOffsetForBucketIndex(mid));
+      final int mid = (lo + hi) >>> 1;
+      final int midVal = readKey(getKeyOffsetForBucketIndex(mid));
       if (midVal < key) {
-        lo = (short) (mid + SHORT_ONE);
+        lo = mid + 1;
       } else if (midVal > key) {
-        hi = (short) (mid - SHORT_ONE);
+        hi = mid - 1;
       } else {
         return mid;
       }
@@ -115,8 +104,8 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
     return -1;
   }
 
-  private short readKey(int position) {
-    return mBuffer.getShort(position);
+  private int readKey(int position) {
+    return mBuffer.getShort(position) & 0xFFFF;
   }
 
   private double readDoubleValue(int bufferPosition) {
@@ -166,9 +155,7 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
       mBuffer.order(ByteOrder.LITTLE_ENDIAN);
     }
     // count
-    mCount = mBuffer.getShort();
-    // size
-    mSizeOfData = mBuffer.getInt();
+    mCount = mBuffer.getShort() & 0xFFFF;
   }
 
   /**
@@ -177,13 +164,13 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
    * @param key Key to search for
    * @return true if and only if the Key received as a parameter is stored in the MapBuffer.
    */
-  public boolean hasKey(short key) {
+  public boolean hasKey(int key) {
     // TODO T83483191: Add tests
     return getBucketIndexForKey(key) != -1;
   }
 
   /** @return amount of elements stored into the MapBuffer */
-  public short getCount() {
+  public int getCount() {
     importByteBufferAndReadHeader();
     return mCount;
   }
@@ -192,7 +179,7 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
    * @param key {@link int} representing the key
    * @return return the int associated to the Key received as a parameter.
    */
-  public int getInt(short key) {
+  public int getInt(int key) {
     // TODO T83483191: extract common code of "get methods"
     return readIntValue(getValueOffsetForKey(key));
   }
@@ -201,7 +188,7 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
    * @param key {@link int} representing the key
    * @return return the double associated to the Key received as a parameter.
    */
-  public double getDouble(short key) {
+  public double getDouble(int key) {
     return readDoubleValue(getValueOffsetForKey(key));
   }
 
@@ -209,11 +196,11 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
    * @param key {@link int} representing the key
    * @return return the int associated to the Key received as a parameter.
    */
-  public String getString(short key) {
+  public String getString(int key) {
     return readStringValue(getValueOffsetForKey(key));
   }
 
-  public boolean getBoolean(short key) {
+  public boolean getBoolean(int key) {
     return readBooleanValue(getValueOffsetForKey(key));
   }
 
@@ -221,7 +208,7 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
    * @param key {@link int} representing the key
    * @return return the int associated to the Key received as a parameter.
    */
-  public ReadableMapBuffer getMapBuffer(short key) {
+  public ReadableMapBuffer getMapBuffer(int key) {
     return readMapBufferValue(getValueOffsetForKey(key));
   }
 
@@ -241,8 +228,8 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
     return mBuffer;
   }
 
-  private void assertKeyExists(short key, int bucketIndex) {
-    short storedKey = mBuffer.getShort(getKeyOffsetForBucketIndex(bucketIndex));
+  private void assertKeyExists(int key, int bucketIndex) {
+    int storedKey = readKey(getKeyOffsetForBucketIndex(bucketIndex));
     if (storedKey != key) {
       throw new IllegalStateException(
           "Stored key doesn't match parameter - expected: " + key + " - found: " + storedKey);
@@ -277,8 +264,8 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
   @Override
   public Iterator<MapBufferEntry> iterator() {
     return new Iterator<MapBufferEntry>() {
-      short current = 0;
-      short last = (short) (getCount() - SHORT_ONE);
+      int current = 0;
+      final int last = getCount() - 1;
 
       @Override
       public boolean hasNext() {
@@ -301,7 +288,7 @@ public class ReadableMapBuffer implements Iterable<ReadableMapBuffer.MapBufferEn
     }
 
     /** @return a {@link short} that represents the key of this {@link MapBufferEntry}. */
-    public short getKey() {
+    public int getKey() {
       return readKey(mBucketOffset);
     }
 

ReactAndroid/src/main/java/com/facebook/react/views/text/TextLayoutManagerMapBuffer.java

@@ -117,7 +117,7 @@ public class TextLayoutManagerMapBuffer {
       SpannableStringBuilder sb,
       List<SetSpanOperation> ops) {
 
-    for (short i = 0, length = fragments.getCount(); i < length; i++) {
+    for (int i = 0, length = fragments.getCount(); i < length; i++) {
       ReadableMapBuffer fragment = fragments.getMapBuffer(i);
       int start = sb.length();