Test that creating overlapping and non-overlapping partial bitvectors behaves as expected.

2 files changed, 45 insertions, 5 deletions

diff --git a/searchlib/src/tests/common/bitvector/bitvector_test.cpp b/searchlib/src/tests/common/bitvector/bitvector_test.cpp
index 9afc4601801..fcda2408afb 100644
--- a/searchlib/src/tests/common/bitvector/bitvector_test.cpp
+++ b/searchlib/src/tests/common/bitvector/bitvector_test.cpp
@@ -712,4 +712,36 @@ TEST("require that growable bit vectors keeps memory allocator")
     g.reclaim(2);
 }
 
+TEST("require that creating partial nonoverlapping vector is cleared") {
+    AllocatedBitVector org(1000);
+    org.setInterval(org.getStartIndex(), org.size());
+    EXPECT_EQUAL(1000u, org.countTrueBits());
+
+    BitVector::UP after = BitVector::create(org, 2000, 3000);
+    EXPECT_EQUAL(2000u, after->getStartIndex());
+    EXPECT_EQUAL(3000u, after->size());
+    EXPECT_EQUAL(0u, after->countTrueBits());
+
+    BitVector::UP before = BitVector::create(*after, 0, 1000);
+    EXPECT_EQUAL(0u, before->getStartIndex());
+    EXPECT_EQUAL(1000u, before->size());
+    EXPECT_EQUAL(0u, before->countTrueBits());
+}
+
+TEST("require that creating partial overlapping vector is properly copied") {
+    AllocatedBitVector org(1000);
+    org.setInterval(org.getStartIndex(), org.size());
+    EXPECT_EQUAL(1000u, org.countTrueBits());
+
+    BitVector::UP after = BitVector::create(org, 900, 1100);
+    EXPECT_EQUAL(900u, after->getStartIndex());
+    EXPECT_EQUAL(1100u, after->size());
+    EXPECT_EQUAL(100u, after->countTrueBits());
+
+    BitVector::UP before = BitVector::create(*after, 0, 1000);
+    EXPECT_EQUAL(0u, before->getStartIndex());
+    EXPECT_EQUAL(1000u, before->size());
+    EXPECT_EQUAL(100u, before->countTrueBits());
+}
+
 TEST_MAIN() { TEST_RUN_ALL(); }
diff --git a/searchlib/src/vespa/searchlib/common/partialbitvector.cpp b/searchlib/src/vespa/searchlib/common/partialbitvector.cpp
index af4e2efd315..b5733e8cc79 100644
--- a/searchlib/src/vespa/searchlib/common/partialbitvector.cpp
+++ b/searchlib/src/vespa/searchlib/common/partialbitvector.cpp
@@ -20,11 +20,19 @@ PartialBitVector::PartialBitVector(const BitVector & org, Index start, Index end
     _alloc(allocatePaddedAndAligned(start, end))
 {
     init(_alloc.get(), start, end);
-    const Word * startWord = org.getWordIndex(start);
-    size_t numBytes2Copy = numActiveBytes(start, std::min(org.size(), end));
-    memcpy(_alloc.get(), startWord, numBytes2Copy);
-    if (org.size() < end) {
-        clearInterval(org.size(), end);
+    Range range = sanitize(org.range());
+    if (range.validNonZero()) {
+        const Word *startWord = org.getWordIndex(range.start());
+        size_t numBytes2Copy = numActiveBytes(range.start(), range.end());
+        memcpy(getWordIndex(range.start()), startWord, numBytes2Copy);
+        if (range.end() < end) {
+            clearInterval(range.end(), end);
+        }
+        if (start < range.start()) {
+            clearInterval(start, range.start());
+        }
+    } else {
+        clear();
     }
     set_bit_no_range_check(size());
 }