Function TestPutValue

cpp/src/arrow/util/rle_encoding_test.cc:181–205

Write up to 'num_vals' values with width 'bit_width' and reads them back.

// Write up to 'num_vals' values with width 'bit_width' and reads them back.
static void TestPutValue(int bit_width, uint64_t num_vals) {
  // The max value representable in `bit_width` bits.
  const uint64_t max = std::numeric_limits<uint64_t>::max() >> (64 - bit_width);
  num_vals = std::min(num_vals, max);
  int len = static_cast<int>(bit_util::BytesForBits(bit_width * num_vals));
  EXPECT_GT(len, 0);

  std::vector<uint8_t> buffer(len);
  bit_util::BitWriter writer(buffer.data(), len);
  for (uint64_t i = max - num_vals; i < max; i++) {
    bool result = writer.PutValue(i, bit_width);
    EXPECT_TRUE(result);
  }
  writer.Flush();
  EXPECT_EQ(writer.bytes_written(), len);

  bit_util::BitReader reader(buffer.data(), len);
  for (uint64_t i = max - num_vals; i < max; i++) {
    int64_t val = 0;
    bool result = reader.GetValue(bit_width, &val);
    EXPECT_TRUE(result);
    EXPECT_EQ(val, i);
  }
  EXPECT_EQ(reader.bytes_left(), 0);
}

TEST(BitUtil, RoundTripIntValues) {
  for (int width = 1; width < 64; width++) {