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arrow-nightlies / pyarrow   python

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Version: 19.0.0.dev259 

/ include / arrow / util / int_util_overflow.h

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

#pragma once

#include <cstdint>
#include <limits>
#include <type_traits>

#include "arrow/status.h"
#include "arrow/util/macros.h"
#include "arrow/util/visibility.h"

// "safe-math.h" includes <intsafe.h> from the Windows headers.
#include "arrow/util/windows_compatibility.h"
#include "arrow/vendored/portable-snippets/safe-math.h"
// clang-format off (avoid include reordering)
#include "arrow/util/windows_fixup.h"
// clang-format on

namespace arrow {
namespace internal {

// Define functions AddWithOverflow, SubtractWithOverflow, MultiplyWithOverflow
// with the signature `bool(T u, T v, T* out)` where T is an integer type.
// On overflow, these functions return true.  Otherwise, false is returned
// and `out` is updated with the result of the operation.

#define OP_WITH_OVERFLOW(_func_name, _psnip_op, _type, _psnip_type)           \
  [[nodiscard]] static inline bool _func_name(_type u, _type v, _type* out) { \
    return !psnip_safe_##_psnip_type##_##_psnip_op(out, u, v);                \
  }

#define OPS_WITH_OVERFLOW(_func_name, _psnip_op)            \
  OP_WITH_OVERFLOW(_func_name, _psnip_op, int8_t, int8)     \
  OP_WITH_OVERFLOW(_func_name, _psnip_op, int16_t, int16)   \
  OP_WITH_OVERFLOW(_func_name, _psnip_op, int32_t, int32)   \
  OP_WITH_OVERFLOW(_func_name, _psnip_op, int64_t, int64)   \
  OP_WITH_OVERFLOW(_func_name, _psnip_op, uint8_t, uint8)   \
  OP_WITH_OVERFLOW(_func_name, _psnip_op, uint16_t, uint16) \
  OP_WITH_OVERFLOW(_func_name, _psnip_op, uint32_t, uint32) \
  OP_WITH_OVERFLOW(_func_name, _psnip_op, uint64_t, uint64)

OPS_WITH_OVERFLOW(AddWithOverflow, add)
OPS_WITH_OVERFLOW(SubtractWithOverflow, sub)
OPS_WITH_OVERFLOW(MultiplyWithOverflow, mul)
OPS_WITH_OVERFLOW(DivideWithOverflow, div)

#undef OP_WITH_OVERFLOW
#undef OPS_WITH_OVERFLOW

// Define function NegateWithOverflow with the signature `bool(T u, T* out)`
// where T is a signed integer type.  On overflow, these functions return true.
// Otherwise, false is returned and `out` is updated with the result of the
// operation.

#define UNARY_OP_WITH_OVERFLOW(_func_name, _psnip_op, _type, _psnip_type) \
  [[nodiscard]] static inline bool _func_name(_type u, _type* out) {      \
    return !psnip_safe_##_psnip_type##_##_psnip_op(out, u);               \
  }

#define SIGNED_UNARY_OPS_WITH_OVERFLOW(_func_name, _psnip_op)   \
  UNARY_OP_WITH_OVERFLOW(_func_name, _psnip_op, int8_t, int8)   \
  UNARY_OP_WITH_OVERFLOW(_func_name, _psnip_op, int16_t, int16) \
  UNARY_OP_WITH_OVERFLOW(_func_name, _psnip_op, int32_t, int32) \
  UNARY_OP_WITH_OVERFLOW(_func_name, _psnip_op, int64_t, int64)

SIGNED_UNARY_OPS_WITH_OVERFLOW(NegateWithOverflow, neg)

#undef UNARY_OP_WITH_OVERFLOW
#undef SIGNED_UNARY_OPS_WITH_OVERFLOW

/// Signed addition with well-defined behaviour on overflow (as unsigned)
template <typename SignedInt>
SignedInt SafeSignedAdd(SignedInt u, SignedInt v) {
  using UnsignedInt = typename std::make_unsigned<SignedInt>::type;
  return static_cast<SignedInt>(static_cast<UnsignedInt>(u) +
                                static_cast<UnsignedInt>(v));
}

/// Signed subtraction with well-defined behaviour on overflow (as unsigned)
template <typename SignedInt>
SignedInt SafeSignedSubtract(SignedInt u, SignedInt v) {
  using UnsignedInt = typename std::make_unsigned<SignedInt>::type;
  return static_cast<SignedInt>(static_cast<UnsignedInt>(u) -
                                static_cast<UnsignedInt>(v));
}

/// Signed negation with well-defined behaviour on overflow (as unsigned)
template <typename SignedInt>
SignedInt SafeSignedNegate(SignedInt u) {
  using UnsignedInt = typename std::make_unsigned<SignedInt>::type;
  return static_cast<SignedInt>(~static_cast<UnsignedInt>(u) + 1);
}

/// Signed left shift with well-defined behaviour on negative numbers or overflow
template <typename SignedInt, typename Shift>
SignedInt SafeLeftShift(SignedInt u, Shift shift) {
  using UnsignedInt = typename std::make_unsigned<SignedInt>::type;
  return static_cast<SignedInt>(static_cast<UnsignedInt>(u) << shift);
}

}  // namespace internal
}  // namespace arrow