Function CommonBinary

cpp/src/arrow/compute/kernels/codegen_internal.cc:350–394

}

TypeHolder CommonBinary(const TypeHolder* begin, size_t count) {
  bool all_utf8 = true, all_offset32 = true, all_fixed_width = true;

  const TypeHolder* end = begin + count;
  for (auto it = begin; it != end; ++it) {
    auto id = it->type->id();
    // a common varbinary type is only possible if all types are binary like
    switch (id) {
      case Type::STRING:
        all_fixed_width = false;
        continue;
      case Type::BINARY:
        all_fixed_width = false;
        all_utf8 = false;
        continue;
      case Type::FIXED_SIZE_BINARY:
        all_utf8 = false;
        continue;
      case Type::LARGE_STRING:
        all_offset32 = false;
        all_fixed_width = false;
        continue;
      case Type::LARGE_BINARY:
        all_offset32 = false;
        all_fixed_width = false;
        all_utf8 = false;
        continue;
      default:
        return TypeHolder(nullptr);
    }
  }

  if (all_fixed_width) {
    // At least for the purposes of comparison, no need to cast.
    return TypeHolder(nullptr);
  }

  if (all_utf8) {
    if (all_offset32) return utf8();
    return large_utf8();
  }

  if (all_offset32) return binary();
  return large_binary();
}

bool CastableToDecimal(const DataType& type) {
  return is_numeric(type.id()) || is_decimal(type.id());