static uint64_t BytesToInteger()

in src/parquet/arrow/reader.cc [1059:1110]

• 49 lines of code
• 10 McCabe index (conditional complexity)

static uint64_t BytesToInteger(const uint8_t* bytes, int32_t start, int32_t stop) {
  using ::arrow::BitUtil::FromBigEndian;

  const int32_t length = stop - start;

  DCHECK_GE(length, 0);
  DCHECK_LE(length, 8);

  switch (length) {
    case 0:
      return 0;
    case 1:
      return bytes[start];
    case 2:
      return FromBigEndian(*reinterpret_cast<const uint16_t*>(bytes + start));
    case 3: {
      const uint64_t first_two_bytes =
          FromBigEndian(*reinterpret_cast<const uint16_t*>(bytes + start));
      const uint64_t last_byte = bytes[stop - 1];
      return first_two_bytes << 8 | last_byte;
    }
    case 4:
      return FromBigEndian(*reinterpret_cast<const uint32_t*>(bytes + start));
    case 5: {
      const uint64_t first_four_bytes =
          FromBigEndian(*reinterpret_cast<const uint32_t*>(bytes + start));
      const uint64_t last_byte = bytes[stop - 1];
      return first_four_bytes << 8 | last_byte;
    }
    case 6: {
      const uint64_t first_four_bytes =
          FromBigEndian(*reinterpret_cast<const uint32_t*>(bytes + start));
      const uint64_t last_two_bytes =
          FromBigEndian(*reinterpret_cast<const uint16_t*>(bytes + start + 4));
      return first_four_bytes << 16 | last_two_bytes;
    }
    case 7: {
      const uint64_t first_four_bytes =
          FromBigEndian(*reinterpret_cast<const uint32_t*>(bytes + start));
      const uint64_t second_two_bytes =
          FromBigEndian(*reinterpret_cast<const uint16_t*>(bytes + start + 4));
      const uint64_t last_byte = bytes[stop - 1];
      return first_four_bytes << 24 | second_two_bytes << 8 | last_byte;
    }
    case 8:
      return FromBigEndian(*reinterpret_cast<const uint64_t*>(bytes + start));
    default: {
      DCHECK(false);
      return UINT64_MAX;
    }
  }
}