fexpr__eq__.cc

//------------------------------------------------------------------------------
// Copyright 2019-2021 H2O.ai
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// IN THE SOFTWARE.
//------------------------------------------------------------------------------
#include "column/const.h"
#include "column/func_binary.h"
#include "column/isna.h"
#include "expr/fbinary/fexpr__compare__.h"
namespace dt {
namespace expr {


template <typename T>
static bool op_eq(ref_t<T> x, bool xvalid, ref_t<T> y, bool yvalid, int8_t* out)
{
  *out = (xvalid == yvalid) && (x == y || !xvalid);
  return true;
}

template <typename T>
static Column make(Column&& a, Column&& b, dt::Type type) {
  xassert(type.can_be_read_as<T>());
  size_t nrows = a.nrows();
  a.cast_inplace(type);
  b.cast_inplace(type);
  return Column(new FuncBinary2_ColumnImpl<T, T, int8_t>(
    std::move(a), std::move(b), op_eq<T>, nrows, SType::BOOL
  ));
}



std::string FExpr__eq__::name() const {
  return "==";
}

int FExpr__eq__::precedence() const noexcept {
  return 6;
}


Column FExpr__eq__::evaluate1(Column&& lcol, Column&& rcol) const {
  xassert(lcol.nrows() == rcol.nrows());
  auto type1 = lcol.type();
  auto type2 = rcol.type();
  auto type0 = Type::common(type1, type2);

  // `expr == None` should be treated as `isna(expr)`
  if (type1.is_void() || type2.is_void()) {
    if (type1.is_void()) {
      std::swap(lcol, rcol);
    }
    switch (type0.stype()) {
      case SType::VOID:    return Const_ColumnImpl::make_bool_column(lcol.nrows(), true);
      case SType::BOOL:
      case SType::INT8:    return Column(new Isna_ColumnImpl<int8_t>(std::move(lcol)));
      case SType::INT16:   return Column(new Isna_ColumnImpl<int16_t>(std::move(lcol)));
      case SType::DATE32:
      case SType::INT32:   return Column(new Isna_ColumnImpl<int32_t>(std::move(lcol)));
      case SType::TIME64:
      case SType::INT64:   return Column(new Isna_ColumnImpl<int64_t>(std::move(lcol)));
      case SType::FLOAT32: return Column(new Isna_ColumnImpl<float>(std::move(lcol)));
      case SType::FLOAT64: return Column(new Isna_ColumnImpl<double>(std::move(lcol)));
      case SType::STR32:
      case SType::STR64:   return Column(new Isna_ColumnImpl<CString>(std::move(lcol)));
      default: break;
    }
  } else {
    switch (type0.stype()) {
      case SType::BOOL:
      case SType::INT8:    return make<int8_t>(std::move(lcol), std::move(rcol), type0);
      case SType::INT16:   return make<int16_t>(std::move(lcol), std::move(rcol), type0);
      case SType::DATE32:
      case SType::INT32:   return make<int32_t>(std::move(lcol), std::move(rcol), type0);
      case SType::TIME64:
      case SType::INT64:   return make<int64_t>(std::move(lcol), std::move(rcol), type0);
      case SType::FLOAT32: return make<float>(std::move(lcol), std::move(rcol), type0);
      case SType::FLOAT64: return make<double>(std::move(lcol), std::move(rcol), type0);
      case SType::STR32:
      case SType::STR64:   return make<CString>(std::move(lcol), std::move(rcol), type0);
      default: break;
    }
  }
  throw TypeError() << "Operator `==` cannot be applied to columns with "
      "types `" << type1 << "` and `" << type2 << "`";
}






}}  // namespace dt::expr