//===-- Scalar.h ------------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef LLDB_UTILITY_SCALAR_H
#define LLDB_UTILITY_SCALAR_H

#include "lldb/Utility/Status.h"
#include "lldb/lldb-enumerations.h"
#include "lldb/lldb-private-types.h"
#include "lldb/Utility/LLDBAssert.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include <cstddef>
#include <cstdint>

namespace lldb_private {
class DataExtractor;
class Stream;
} // namespace lldb_private

#define NUM_OF_WORDS_INT128 2
#define BITWIDTH_INT128 128
#define NUM_OF_WORDS_INT256 4
#define BITWIDTH_INT256 256
#define NUM_OF_WORDS_INT512 8
#define BITWIDTH_INT512 512

namespace lldb_private {

// A class designed to hold onto values and their corresponding types.
// Operators are defined and Scalar objects will correctly promote their types
// and values before performing these operations. Type promotion currently
// follows the ANSI C type promotion rules.
class Scalar {
public:
  // FIXME: These are host types which seems to be an odd choice.
  enum Type {
    e_void = 0,
    e_sint,
    e_uint,
    e_slong,
    e_ulong,
    e_slonglong,
    e_ulonglong,
    e_sint128,
    e_uint128,
    e_sint256,
    e_uint256,
    e_sint512,
    e_uint512,
    e_float,
    e_double,
    e_long_double
  };

  // Constructors and Destructors
  Scalar();
  Scalar(int v) : m_type(e_sint), m_float(static_cast<float>(0)) {
    m_integer = llvm::APInt(sizeof(int) * 8, v, true);
  }
  Scalar(unsigned int v) : m_type(e_uint), m_float(static_cast<float>(0)) {
    m_integer = llvm::APInt(sizeof(int) * 8, v);
  }
  Scalar(long v) : m_type(e_slong), m_float(static_cast<float>(0)) {
    m_integer = llvm::APInt(sizeof(long) * 8, v, true);
  }
  Scalar(unsigned long v) : m_type(e_ulong), m_float(static_cast<float>(0)) {
    m_integer = llvm::APInt(sizeof(long) * 8, v);
  }
  Scalar(long long v) : m_type(e_slonglong), m_float(static_cast<float>(0)) {
    m_integer = llvm::APInt(sizeof(long long) * 8, v, true);
  }
  Scalar(unsigned long long v)
      : m_type(e_ulonglong), m_float(static_cast<float>(0)) {
    m_integer = llvm::APInt(sizeof(long long) * 8, v);
  }
  Scalar(float v) : m_type(e_float), m_float(v) { m_float = llvm::APFloat(v); }
  Scalar(double v) : m_type(e_double), m_float(v) {
    m_float = llvm::APFloat(v);
  }
  Scalar(long double v)
      : m_type(e_long_double),
        m_float(llvm::APFloat::x87DoubleExtended(),
                llvm::APInt(BITWIDTH_INT128, NUM_OF_WORDS_INT128,
                            (reinterpret_cast<type128 *>(&v))->x)) {}
  Scalar(llvm::APInt v) : m_type(), m_float(static_cast<float>(0)) {
    m_integer = llvm::APInt(v);
    m_type = GetBestTypeForBitSize(m_integer.getBitWidth(), true);
  }
  // Scalar(const RegisterValue& reg_value);
  virtual ~Scalar();

  /// Return the most efficient Scalar::Type for the requested bit size.
  static Type GetBestTypeForBitSize(size_t bit_size, bool sign);

  bool SignExtend(uint32_t bit_pos);

  bool ExtractBitfield(uint32_t bit_size, uint32_t bit_offset);

  bool SetBit(uint32_t bit);

  bool ClearBit(uint32_t bit);

  /// Store the binary representation of this value into the given storage.
  /// Exactly GetByteSize() bytes will be stored, and the buffer must be large
  /// enough to hold this data.
  void GetBytes(llvm::MutableArrayRef<uint8_t> storage) const;

  size_t GetByteSize() const;

  bool GetData(DataExtractor &data, size_t limit_byte_size = UINT32_MAX) const;

  size_t GetAsMemoryData(void *dst, size_t dst_len,
                         lldb::ByteOrder dst_byte_order, Status &error) const;

  bool IsZero() const;

  void Clear() {
    m_type = e_void;
    m_integer.clearAllBits();
  }

  const char *GetTypeAsCString() const { return GetValueTypeAsCString(m_type); }

  void GetValue(Stream *s, bool show_type) const;

  bool IsValid() const {
    return (m_type >= e_sint) && (m_type <= e_long_double);
  }

  /// Convert to an integer with \p bits and the given signedness.
  void TruncOrExtendTo(uint16_t bits, bool sign);

  bool Promote(Scalar::Type type);

  bool MakeSigned();

  bool MakeUnsigned();

  static const char *GetValueTypeAsCString(Scalar::Type value_type);

  static Scalar::Type
  GetValueTypeForSignedIntegerWithByteSize(size_t byte_size);

  static Scalar::Type
  GetValueTypeForUnsignedIntegerWithByteSize(size_t byte_size);

  static Scalar::Type GetValueTypeForFloatWithByteSize(size_t byte_size);

  // All operators can benefits from the implicit conversions that will happen
  // automagically by the compiler, so no temporary objects will need to be
  // created. As a result, we currently don't need a variety of overloaded set
  // value accessors.
  Scalar &operator+=(const Scalar &rhs);
  Scalar &operator<<=(const Scalar &rhs); // Shift left
  Scalar &operator>>=(const Scalar &rhs); // Shift right (arithmetic)
  Scalar &operator&=(const Scalar &rhs);

  // Shifts the current value to the right without maintaining the current sign
  // of the value (if it is signed).
  bool ShiftRightLogical(const Scalar &rhs); // Returns true on success

  // Takes the absolute value of the current value if it is signed, else the
  // value remains unchanged. Returns false if the contained value has a void
  // type.
  bool AbsoluteValue(); // Returns true on success
  // Negates the current value (even for unsigned values). Returns false if the
  // contained value has a void type.
  bool UnaryNegate(); // Returns true on success
  // Inverts all bits in the current value as long as it isn't void or a
  // float/double/long double type. Returns false if the contained value has a
  // void/float/double/long double type, else the value is inverted and true is
  // returned.
  bool OnesComplement(); // Returns true on success

  // Access the type of the current value.
  Scalar::Type GetType() const { return m_type; }

  // Returns a casted value of the current contained data without modifying the
  // current value. FAIL_VALUE will be returned if the type of the value is
  // void or invalid.
  int SInt(int fail_value = 0) const;

  unsigned char UChar(unsigned char fail_value = 0) const;

  signed char SChar(signed char fail_value = 0) const;

  unsigned short UShort(unsigned short fail_value = 0) const;

  short SShort(short fail_value = 0) const;

  unsigned int UInt(unsigned int fail_value = 0) const;

  long SLong(long fail_value = 0) const;

  unsigned long ULong(unsigned long fail_value = 0) const;

  long long SLongLong(long long fail_value = 0) const;

  unsigned long long ULongLong(unsigned long long fail_value = 0) const;

  llvm::APInt SInt128(const llvm::APInt &fail_value) const;

  llvm::APInt UInt128(const llvm::APInt &fail_value) const;

  float Float(float fail_value = 0.0f) const;

  double Double(double fail_value = 0.0) const;

  long double LongDouble(long double fail_value = 0.0) const;

  Status SetValueFromCString(const char *s, lldb::Encoding encoding,
                             size_t byte_size);

  Status SetValueFromData(DataExtractor &data, lldb::Encoding encoding,
                          size_t byte_size);

  static bool UIntValueIsValidForSize(uint64_t uval64, size_t total_byte_size) {
    if (total_byte_size > 8)
      return false;

    if (total_byte_size == 8)
      return true;

    const uint64_t max = (static_cast<uint64_t>(1)
                          << static_cast<uint64_t>(total_byte_size * 8)) -
                         1;
    return uval64 <= max;
  }

  static bool SIntValueIsValidForSize(int64_t sval64, size_t total_byte_size) {
    if (total_byte_size > 8)
      return false;

    if (total_byte_size == 8)
      return true;

    const int64_t max = (static_cast<int64_t>(1)
                         << static_cast<uint64_t>(total_byte_size * 8 - 1)) -
                        1;
    const int64_t min = ~(max);
    return min <= sval64 && sval64 <= max;
  }

protected:
  typedef char schar_t;
  typedef unsigned char uchar_t;
  typedef short sshort_t;
  typedef unsigned short ushort_t;
  typedef int sint_t;
  typedef unsigned int uint_t;
  typedef long slong_t;
  typedef unsigned long ulong_t;
  typedef long long slonglong_t;
  typedef unsigned long long ulonglong_t;
  typedef float float_t;
  typedef double double_t;
  typedef long double long_double_t;

  // Classes that inherit from Scalar can see and modify these
  Scalar::Type m_type;
  llvm::APInt m_integer;
  llvm::APFloat m_float;

  template <typename T> T GetAs(T fail_value) const;

private:
  friend const Scalar operator+(const Scalar &lhs, const Scalar &rhs);
  friend const Scalar operator-(const Scalar &lhs, const Scalar &rhs);
  friend const Scalar operator/(const Scalar &lhs, const Scalar &rhs);
  friend const Scalar operator*(const Scalar &lhs, const Scalar &rhs);
  friend const Scalar operator&(const Scalar &lhs, const Scalar &rhs);
  friend const Scalar operator|(const Scalar &lhs, const Scalar &rhs);
  friend const Scalar operator%(const Scalar &lhs, const Scalar &rhs);
  friend const Scalar operator^(const Scalar &lhs, const Scalar &rhs);
  friend const Scalar operator<<(const Scalar &lhs, const Scalar &rhs);
  friend const Scalar operator>>(const Scalar &lhs, const Scalar &rhs);
  friend bool operator==(const Scalar &lhs, const Scalar &rhs);
  friend bool operator!=(const Scalar &lhs, const Scalar &rhs);
  friend bool operator<(const Scalar &lhs, const Scalar &rhs);
  friend bool operator<=(const Scalar &lhs, const Scalar &rhs);
  friend bool operator>(const Scalar &lhs, const Scalar &rhs);
  friend bool operator>=(const Scalar &lhs, const Scalar &rhs);
};

// Split out the operators into a format where the compiler will be able to
// implicitly convert numbers into Scalar objects.
//
// This allows code like:
//      Scalar two(2);
//      Scalar four = two * 2;
//      Scalar eight = 2 * four;    // This would cause an error if the
//                                  // operator* was implemented as a
//                                  // member function.
// SEE:
//  Item 19 of "Effective C++ Second Edition" by Scott Meyers
//  Differentiate among members functions, non-member functions, and
//  friend functions
const Scalar operator+(const Scalar &lhs, const Scalar &rhs);
const Scalar operator-(const Scalar &lhs, const Scalar &rhs);
const Scalar operator/(const Scalar &lhs, const Scalar &rhs);
const Scalar operator*(const Scalar &lhs, const Scalar &rhs);
const Scalar operator&(const Scalar &lhs, const Scalar &rhs);
const Scalar operator|(const Scalar &lhs, const Scalar &rhs);
const Scalar operator%(const Scalar &lhs, const Scalar &rhs);
const Scalar operator^(const Scalar &lhs, const Scalar &rhs);
const Scalar operator<<(const Scalar &lhs, const Scalar &rhs);
const Scalar operator>>(const Scalar &lhs, const Scalar &rhs);
bool operator==(const Scalar &lhs, const Scalar &rhs);
bool operator!=(const Scalar &lhs, const Scalar &rhs);
bool operator<(const Scalar &lhs, const Scalar &rhs);
bool operator<=(const Scalar &lhs, const Scalar &rhs);
bool operator>(const Scalar &lhs, const Scalar &rhs);
bool operator>=(const Scalar &lhs, const Scalar &rhs);

llvm::raw_ostream &operator<<(llvm::raw_ostream &os, const Scalar &scalar);

} // namespace lldb_private

#endif // LLDB_UTILITY_SCALAR_H