From 6697abbb285e9edb5012c2d161ce0546ad9dbae0 Mon Sep 17 00:00:00 2001
From: Adrien Grand <jpountz@apache.org>
Date: Thu, 16 Oct 2014 14:01:53 +0000
Subject: [PATCH] LUCENE-6009: Remove redundant == NO_MORE_DOCS checks.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1632314 13f79535-47bb-0310-9956-ffa450edef68
---
 .../org/apache/lucene/util/FixedBitSet.java   | 21 ++-----------
 .../org/apache/lucene/util/NotDocIdSet.java   |  3 --
 .../apache/lucene/util/RoaringDocIdSet.java   |  3 --
 .../apache/lucene/util/SparseFixedBitSet.java | 30 +++++++------------
 4 files changed, 12 insertions(+), 45 deletions(-)

diff --git a/lucene/core/src/java/org/apache/lucene/util/FixedBitSet.java b/lucene/core/src/java/org/apache/lucene/util/FixedBitSet.java
index ba645a50140..e155a70d954 100644
--- a/lucene/core/src/java/org/apache/lucene/util/FixedBitSet.java
+++ b/lucene/core/src/java/org/apache/lucene/util/FixedBitSet.java
@@ -59,24 +59,7 @@ public final class FixedBitSet extends DocIdSet implements MutableBits {
     
     @Override
     public int nextDoc() {
-      if (doc == NO_MORE_DOCS || ++doc >= numBits) {
-        return doc = NO_MORE_DOCS;
-      }
-      int i = doc >> 6;
-      long word = bits[i] >> doc;  // skip all the bits to the right of index
-      
-      if (word != 0) {
-        return doc = doc + Long.numberOfTrailingZeros(word);
-      }
-      
-      while (++i < numWords) {
-        word = bits[i];
-        if (word != 0) {
-          return doc = (i << 6) + Long.numberOfTrailingZeros(word);
-        }
-      }
-      
-      return doc = NO_MORE_DOCS;
+      return advance(doc + 1);
     }
     
     @Override
@@ -91,7 +74,7 @@ public final class FixedBitSet extends DocIdSet implements MutableBits {
     
     @Override
     public int advance(int target) {
-      if (doc == NO_MORE_DOCS || target >= numBits) {
+      if (target >= numBits) {
         return doc = NO_MORE_DOCS;
       }
       int i = target >> 6;
diff --git a/lucene/core/src/java/org/apache/lucene/util/NotDocIdSet.java b/lucene/core/src/java/org/apache/lucene/util/NotDocIdSet.java
index 44f883877d6..6261de92fce 100644
--- a/lucene/core/src/java/org/apache/lucene/util/NotDocIdSet.java
+++ b/lucene/core/src/java/org/apache/lucene/util/NotDocIdSet.java
@@ -82,9 +82,6 @@ public final class NotDocIdSet extends DocIdSet {
 
       @Override
       public int nextDoc() throws IOException {
-        if (doc == NO_MORE_DOCS) {
-          return NO_MORE_DOCS;
-        }
         return advance(doc + 1);
       }
 
diff --git a/lucene/core/src/java/org/apache/lucene/util/RoaringDocIdSet.java b/lucene/core/src/java/org/apache/lucene/util/RoaringDocIdSet.java
index 5f6844add26..93d4ab85bfa 100644
--- a/lucene/core/src/java/org/apache/lucene/util/RoaringDocIdSet.java
+++ b/lucene/core/src/java/org/apache/lucene/util/RoaringDocIdSet.java
@@ -282,9 +282,6 @@ public class RoaringDocIdSet extends DocIdSet {
 
     @Override
     public int nextDoc() throws IOException {
-      if (doc == NO_MORE_DOCS) {
-        return NO_MORE_DOCS;
-      }
       final int subNext = sub.nextDoc();
       if (subNext == NO_MORE_DOCS) {
         return firstDocFromNextBlock();
diff --git a/lucene/core/src/java/org/apache/lucene/util/SparseFixedBitSet.java b/lucene/core/src/java/org/apache/lucene/util/SparseFixedBitSet.java
index 23448208033..7a971956342 100644
--- a/lucene/core/src/java/org/apache/lucene/util/SparseFixedBitSet.java
+++ b/lucene/core/src/java/org/apache/lucene/util/SparseFixedBitSet.java
@@ -248,16 +248,17 @@ public class SparseFixedBitSet extends DocIdSet implements Bits {
 
     @Override
     public int nextDoc() throws IOException {
-      if (++doc >= length) {
-        return doc = NO_MORE_DOCS;
-      }
-      return currentOrNextDoc();
+      return advance(doc + 1);
     }
 
-    private int currentOrNextDoc() {
-      final int i4096 = doc >>> 12;
+    @Override
+    public int advance(int target) throws IOException {
+      final int i4096 = target >>> 12;
+      if (i4096 >= indices.length) {
+        return doc = NO_MORE_DOCS;
+      }
       final long index = indices[i4096];
-      int i64 = doc >>> 6;
+      int i64 = target >>> 6;
       long indexBits = index >>> i64;
       if (indexBits == 0) {
         // if the index is zero, it means that there is no value in the
@@ -270,7 +271,7 @@ public class SparseFixedBitSet extends DocIdSet implements Bits {
       } else {
         // We know we still have some 64-bits blocks that have bits set, let's
         // advance to the next one by skipping trailing zeros of the index
-        int i1 = doc & 0x3F;
+        int i1 = target & 0x3F;
         int trailingZeros = Long.numberOfTrailingZeros(indexBits);
         if (trailingZeros != 0) {
           // no bits in the current long, go to the next one
@@ -285,7 +286,7 @@ public class SparseFixedBitSet extends DocIdSet implements Bits {
         int longIndex = Long.bitCount(index & ((1L << i64) - 1)); // shifts are mod 64 in java
         final long[] longArray = bits[i4096];
         assert longArray[longIndex] != 0;
-        long bits = SparseFixedBitSet.this.bits[i4096][longIndex] >>> i1; // shifts are mod 64 in java
+        long bits = longArray[longIndex] >>> i1; // shifts are mod 64 in java
         if (bits != 0L) {
           // hurray, we found some non-zero bits, this gives us the next document:
           i1 += Long.numberOfTrailingZeros(bits);
@@ -312,17 +313,6 @@ public class SparseFixedBitSet extends DocIdSet implements Bits {
       }
     }
 
-    @Override
-    public int advance(int target) throws IOException {
-      if (target >= length) {
-        return doc = NO_MORE_DOCS;
-      } else {
-        doc = target;
-      }
-
-      return currentOrNextDoc();
-    }
-
     @Override
     public long cost() {
       // although constant-time, approximateCardinality is a bit expensive so