Switch back to ByteBlockPool

Author: dungba88

lucene/core/src/java/org/apache/lucene/util/ByteBlockPool.java

@@ -256,6 +256,18 @@ public void readBytes(final long offset, final byte[] bytes, int bytesOffset, in
     }
   }
 
+  /**
+   * Read a single byte at the given offset
+   *
+   * @param offset the offset to read
+   * @return the byte
+   */
+  public byte readByte(final long offset) {
+    int bufferIndex = (int) (offset >> BYTE_BLOCK_SHIFT);
+    int pos = (int) (offset & BYTE_BLOCK_MASK);
+    return buffers[bufferIndex][pos];
+  }
+
   @Override
   public long ramBytesUsed() {
     long size = BASE_RAM_BYTES;

lucene/core/src/java/org/apache/lucene/util/fst/RelativeReverseBytesReader.java renamed to lucene/core/src/java/org/apache/lucene/util/fst/ByteBlockPoolReverseBytesReader.java

@@ -17,41 +17,45 @@
 package org.apache.lucene.util.fst;
 
 import java.io.IOException;
+import org.apache.lucene.util.ByteBlockPool;
 
-/** Same as ReverseBytesReader but acts upon a relative position */
-final class RelativeReverseBytesReader extends FST.BytesReader {
+/** Reads in reverse from a ByteBlockPool. */
+final class ByteBlockPoolReverseBytesReader extends FST.BytesReader {
 
-  private final FST.BytesReader reader;
+  private final ByteBlockPool buf;
   private final long relativePos;
+  private long pos;
 
-  public RelativeReverseBytesReader(byte[] bytes, long relativePos) {
-    this.reader = new ReverseBytesReader(bytes);
+  public ByteBlockPoolReverseBytesReader(ByteBlockPool buf, long relativePos) {
+    this.buf = buf;
     this.relativePos = relativePos;
   }
 
   @Override
-  public byte readByte() throws IOException {
-    return reader.readByte();
+  public byte readByte() {
+    return buf.readByte(pos--);
   }
 
   @Override
-  public void readBytes(byte[] b, int offset, int len) throws IOException {
-    reader.readBytes(b, offset, len);
+  public void readBytes(byte[] b, int offset, int len) {
+    for (int i = 0; i < len; i++) {
+      b[offset + i] = buf.readByte(pos--);
+    }
   }
 
   @Override
-  public void skipBytes(long count) throws IOException {
-    reader.skipBytes(count);
+  public void skipBytes(long numBytes) throws IOException {
+    pos -= numBytes;
   }
 
   @Override
   public long getPosition() {
-    return reader.getPosition() + relativePos;
+    return pos + relativePos;
   }
 
   @Override
   public void setPosition(long pos) {
-    reader.setPosition(pos - relativePos);
+    this.pos = pos - relativePos;
   }
 
   @Override

lucene/core/src/java/org/apache/lucene/util/fst/BytesStore.java

@@ -444,11 +444,7 @@ public boolean reversed() {
 
   @Override
   public FST.BytesReader getReverseBytesReader() {
-    return getReverseReader(true);
-  }
-
-  FST.BytesReader getReverseReader(boolean allowSingle) {
-    if (allowSingle && blocks.size() == 1) {
+    if (blocks.size() == 1) {
       return new ReverseBytesReader(blocks.get(0));
     }
     return new FST.BytesReader() {