Revert D18662578: Eliminate need for reading upper bound at construction.

Differential Revision:
D18662578 (https://github.com/facebook/folly/commit/42d5bf14cd6feafa91beeb214d2441bf27ab03c7)

Original commit changeset: e04a99208848

fbshipit-source-id: 57a66a9c90955d67f942db4a3cad15910ee74178

folly/experimental/test/CodingTestUtils.h

@@ -35,11 +35,6 @@
 namespace folly {
 namespace compression {
 
-template <typename ValueType, class List>
-folly::Optional<std::size_t> getUniverseUpperBound(const List& /* list */) {
-  return folly::none;
-}
-
 template <class URNG>
 std::vector<uint64_t> generateRandomList(
     size_t n,
@@ -273,15 +268,6 @@ void testSkipTo(const std::vector<uint64_t>& data, const List& list) {
     EXPECT_EQ(reader.position(), reader.size());
     EXPECT_FALSE(reader.next());
   }
-  // Skip past the last element and before the upperBound.
-  using ValueType = typename Reader::ValueType;
-  if (const auto upperBound = getUniverseUpperBound<ValueType>(list)) {
-    Reader reader(list);
-    EXPECT_FALSE(reader.skipTo(*upperBound));
-    EXPECT_FALSE(reader.valid());
-    EXPECT_EQ(reader.position(), reader.size());
-    EXPECT_FALSE(reader.next());
-  }
 }
 
 template <class Reader, class List>
@@ -376,19 +362,9 @@ void testEmpty() {
   }
 }
 
-// `upperBoundExtension` is required to inject additional 0-blocks
-// at the end of the list. This allows us to test lists with a large gap between
-// last element and universe upper bound, to exercise bounds-checking when
-// skipping past the last element
 template <class Reader, class Encoder>
-void testAll(
-    const std::vector<uint64_t>& data,
-    uint64_t upperBoundExtension = 0) {
-  Encoder encoder(data.size(), data.back() + upperBoundExtension);
-  for (const auto value : data) {
-    encoder.add(value);
-  }
-  auto list = encoder.finish();
+void testAll(const std::vector<uint64_t>& data) {
+  auto list = Encoder::encode(data.begin(), data.end());
   testNext<Reader>(data, list);
   testSkip<Reader>(data, list);
   testSkipTo<Reader>(data, list);

folly/experimental/test/EliasFanoCodingTest.cpp

@@ -21,32 +21,11 @@
 #include <vector>
 
 #include <folly/Benchmark.h>
-#include <folly/Optional.h>
-#include <folly/Random.h>
 #include <folly/experimental/EliasFanoCoding.h>
 #include <folly/experimental/Select64.h>
 #include <folly/experimental/test/CodingTestUtils.h>
 #include <folly/init/Init.h>
 
-namespace folly {
-namespace compression {
-
-// Overload to help CodingTestUtils retrieve the universe upperbound
-// of the list for certain test cases.
-template <typename ValueType, typename T>
-folly::Optional<std::size_t> getUniverseUpperBound(
-    const EliasFanoCompressedListBase<T>& list) {
-  constexpr ValueType maxUpperValue = std::numeric_limits<ValueType>::max();
-  const ValueType maxUpperBits = maxUpperValue >> list.numLowerBits;
-  const ValueType upperBitsUniverse = std::min(
-      static_cast<ValueType>(8 * list.upperSizeBytes - list.size),
-      maxUpperBits);
-  return (upperBitsUniverse << list.numLowerBits) |
-      ((1 << list.numLowerBits) - 1);
-}
-} // namespace compression
-} // namespace folly
-
 using namespace folly::compression;
 
 namespace {
@@ -135,13 +114,6 @@ class EliasFanoCodingTest : public ::testing::Test {
     // max() cannot be read, as it is assumed an invalid value.
     // TODO(ott): It should be possible to lift this constraint.
     testAll<Reader, Encoder>({0, 1, std::numeric_limits<uint32_t>::max() - 1});
-    // Test data with additional trailing 0s in the upperBits by extending
-    // the upper bound.
-    constexpr uint64_t minUpperBoundExtension = 2;
-    constexpr uint64_t maxUpperBoundExtension = 1024;
-    testAll<Reader, Encoder>(
-        generateRandomList(100 * 1000, 10 * 1000 * 1000),
-        folly::Random::rand32(minUpperBoundExtension, maxUpperBoundExtension));
   }
 };