Add ParsableByteArray#ensureCapacity() method that keeps data

#exofixit

PiperOrigin-RevId: 344845328

library/common/src/main/java/com/google/android/exoplayer2/util/ParsableByteArray.java

@@ -19,6 +19,7 @@ import androidx.annotation.Nullable;
 import com.google.common.base.Charsets;
 import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
+import java.util.Arrays;
 
 /**
  * Wraps a byte array, providing a set of methods for parsing data from it. Numerical values are
@@ -100,8 +101,21 @@ public final class ParsableByteArray {
   }
 
   /**
-   * Returns the number of bytes yet to be read.
+   * Ensures the backing array is at least {@code requiredCapacity} long.
+   *
+   * <p>{@link #getPosition() position}, {@link #limit() limit}, and all data in the underlying
+   * array (including that beyond {@link #limit()}) are preserved.
+   *
+   * <p>This might replace or wipe the {@link #getData() underlying array}, potentially invalidating
+   * any local references.
    */
+  public void ensureCapacity(int requiredCapacity) {
+    if (requiredCapacity > capacity()) {
+      data = Arrays.copyOf(data, requiredCapacity);
+    }
+  }
+
+  /** Returns the number of bytes yet to be read. */
   public int bytesLeft() {
     return limit - position;
   }
@@ -148,8 +162,8 @@ public final class ParsableByteArray {
    *
    * <p>Changes to this array are reflected in the results of the {@code read...()} methods.
    *
-   * <p>This reference must be assumed to become invalid when {@link #reset} is called (because the
+   * <p>This reference must be assumed to become invalid when {@link #reset} or {@link
-   * array might get reallocated).
+   * #ensureCapacity} are called (because the array might get reallocated).
    */
   public byte[] getData() {
     return data;

library/common/src/main/java/com/google/android/exoplayer2/util/Util.java

@@ -2214,9 +2214,8 @@ public final class Util {
     if (input.bytesLeft() <= 0) {
       return false;
     }
-    byte[] outputData = output.getData();
+    if (output.capacity() < input.bytesLeft()) {
-    if (outputData.length < input.bytesLeft()) {
+      output.ensureCapacity(2 * input.bytesLeft());
-      outputData = new byte[2 * input.bytesLeft()];
     }
     if (inflater == null) {
       inflater = new Inflater();
@@ -2225,16 +2224,17 @@ public final class Util {
     try {
       int outputSize = 0;
       while (true) {
-        outputSize += inflater.inflate(outputData, outputSize, outputData.length - outputSize);
+        outputSize +=
+            inflater.inflate(output.getData(), outputSize, output.capacity() - outputSize);
         if (inflater.finished()) {
-          output.reset(outputData, outputSize);
+          output.setLimit(outputSize);
           return true;
         }
         if (inflater.needsDictionary() || inflater.needsInput()) {
           return false;
         }
-        if (outputSize == outputData.length) {
+        if (outputSize == output.capacity()) {
-          outputData = Arrays.copyOf(outputData, outputData.length * 2);
+          output.ensureCapacity(output.capacity() * 2);
         }
       }
     } catch (DataFormatException e) {

library/common/src/test/java/com/google/android/exoplayer2/util/ParsableByteArrayTest.java

@@ -20,6 +20,7 @@ import static java.nio.charset.Charset.forName;
 import static org.junit.Assert.fail;
 
 import androidx.test.ext.junit.runners.AndroidJUnit4;
+import com.google.common.primitives.Bytes;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 import org.junit.Test;
@@ -38,6 +39,36 @@ public final class ParsableByteArrayTest {
     return testArray;
   }
 
+  @Test
+  public void ensureCapacity_doesntReallocateNeedlesslyAndPreservesPositionAndLimit() {
+    ParsableByteArray array = getTestDataArray();
+    byte[] dataBefore = array.getData();
+    byte[] copyOfDataBefore = dataBefore.clone();
+
+    array.setPosition(3);
+    array.setLimit(4);
+    array.ensureCapacity(array.capacity() - 1);
+
+    assertThat(array.getData()).isSameInstanceAs(dataBefore);
+    assertThat(array.getData()).isEqualTo(copyOfDataBefore);
+    assertThat(array.getPosition()).isEqualTo(3);
+    assertThat(array.limit()).isEqualTo(4);
+  }
+
+  @Test
+  public void ensureCapacity_preservesDataPositionAndLimitWhenReallocating() {
+    ParsableByteArray array = getTestDataArray();
+    byte[] copyOfDataBefore = array.getData().clone();
+
+    array.setPosition(3);
+    array.setLimit(4);
+    array.ensureCapacity(array.capacity() + 1);
+
+    assertThat(array.getData()).isEqualTo(Bytes.concat(copyOfDataBefore, new byte[] {0}));
+    assertThat(array.getPosition()).isEqualTo(3);
+    assertThat(array.limit()).isEqualTo(4);
+  }
+
   @Test
   public void readShort() {
     testReadShort((short) -1);

library/extractor/src/main/java/com/google/android/exoplayer2/extractor/mkv/MatroskaExtractor.java

@@ -1341,9 +1341,7 @@ public class MatroskaExtractor implements Extractor {
       return;
     }
     if (scratch.capacity() < requiredLength) {
-      scratch.reset(
+      scratch.ensureCapacity(max(scratch.capacity() * 2, requiredLength));
-          Arrays.copyOf(scratch.getData(), max(scratch.getData().length * 2, requiredLength)),
-          scratch.limit());
     }
     input.readFully(scratch.getData(), scratch.limit(), requiredLength - scratch.limit());
     scratch.setLimit(requiredLength);

library/extractor/src/main/java/com/google/android/exoplayer2/extractor/ogg/OggPacket.java

@@ -87,11 +87,7 @@ import java.util.Arrays;
       int size = calculatePacketSize(currentSegmentIndex);
       int segmentIndex = currentSegmentIndex + segmentCount;
       if (size > 0) {
-        if (packetArray.capacity() < packetArray.limit() + size) {
+        packetArray.ensureCapacity(packetArray.limit() + size);
-          packetArray.reset(
-              Arrays.copyOf(packetArray.getData(), packetArray.limit() + size),
-              /* limit= */ packetArray.limit());
-        }
         input.readFully(packetArray.getData(), packetArray.limit(), size);
         packetArray.setLimit(packetArray.limit() + size);
         populated = pageHeader.laces[segmentIndex - 1] != 255;

library/extractor/src/main/java/com/google/android/exoplayer2/extractor/ts/SectionReader.java

@@ -23,7 +23,6 @@ import com.google.android.exoplayer2.extractor.ExtractorOutput;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.TimestampAdjuster;
 import com.google.android.exoplayer2.util.Util;
-import java.util.Arrays;
 
 /**
  * Reads section data packets and feeds the whole sections to a given {@link SectionPayloadReader}.
@@ -107,12 +106,9 @@ public final class SectionReader implements TsPayloadReader {
               (((secondHeaderByte & 0x0F) << 8) | thirdHeaderByte) + SECTION_HEADER_LENGTH;
           if (sectionData.capacity() < totalSectionLength) {
             // Ensure there is enough space to keep the whole section.
-            byte[] bytes = sectionData.getData();
+            int limit =
-            int limit = min(MAX_SECTION_LENGTH, max(totalSectionLength, bytes.length * 2));
+                min(MAX_SECTION_LENGTH, max(totalSectionLength, sectionData.capacity() * 2));
-            if (limit > bytes.length) {
+            sectionData.ensureCapacity(limit);
-              bytes = Arrays.copyOf(sectionData.getData(), limit);
-            }
-            sectionData.reset(bytes, limit);
           }
         }
       } else {