cs440-final/integer.cpp

#include <algorithm>
#include <cassert>
#include <cstddef>
#include <iostream>
#define todo(msg)                                                              \
  std::cerr << msg << std::endl;                                               \
  assert(false);
// TODO: try to maximize rvalue usage to reuse resources
// "Use rvalue references to reuse the resources of temporaries when possible,
// particularly for binary operands."

// [50 pts, 10 commits] Write a class named Integer that can hold
// arbitrary-length, signed integers. Use unsigned chars (i.e., bytes) for the
// internal storage. Put one decimal digit per byte. The ones digit should be
// first in the array, etc. You must use a pointer to unsigned char internally
// to point to the data. The internal array must grow as needed, but you do not
// need to shrink it. The constructor should take a single argument of a long
// type, used to initialize the number. Use a default argument so that a
// constructor with no arguments will initialize the integer to 0. Use rvalue
// references to reuse the resources of temporaries when possible, particularly
// for binary operands. Support the plus, minus, unary minus, multiplication,
// equality, greater/less, copy/move assignment/constructor Support outputting
// to a std::ostream via the << operator. Where it makes sense, allow operands
// to be of class Integer, or any integer type. In particular, you need to
// support operations like 1234 + Integer_obj. You should also support
// conversion of Integer to an unsigned long, so that operations like bitwise
// AND will work: Integer_object^123.
class Integer {
  using byte = unsigned char;
  // bytes are litle endian
  byte *bytes;
  bool isNegative;
  std::size_t size;

public:
  Integer(long long num = 0)
      : bytes{new byte[sizeof(long long)]}, isNegative{num < 0},
        size{sizeof(long long)} {
    for (std::size_t i = 0; i < size; i++) {
      bytes[i] = num % 256;
      num /= 256;
    }
  }
  Integer(Integer const &rhs)
      : bytes{new byte[rhs.size]}, isNegative{rhs.isNegative}, size{rhs.size} {
    for (std::size_t i = 0; i < size; i++) {
      bytes[i] = rhs.bytes[i];
    }
  }
  Integer(Integer &&rhs)
      : bytes{rhs.bytes}, isNegative{rhs.isNegative}, size{rhs.size} {
    rhs.bytes = nullptr;
  }
  ~Integer() {
    delete[] bytes;
    bytes = nullptr;
  }
  Integer &operator=(Integer const &rhs) {
    delete[] bytes;

    bytes = new byte[rhs.size];
    size = rhs.size;
    isNegative = rhs.isNegative;
    for (std::size_t i = 0; i < size; i++) {
      bytes[i] = rhs.bytes[i];
    }
    return *this;
  }
  Integer &operator=(Integer &&rhs) {
    bytes = rhs.bytes;
    rhs.bytes = nullptr;
    size = rhs.size;
    isNegative = rhs.isNegative;
    return *this;
  }
  friend Integer &operator+=(Integer &lhs, Integer const &rhs) {
    todo("+=");
    return lhs;
  }
  friend Integer &operator-=(Integer &lhs, Integer const &rhs) {
    todo("-=");
    return lhs;
  }
  friend Integer &operator*=(Integer &lhs, Integer const &rhs) {
    Integer tmp = std::move(lhs);
    Integer tmp_r = rhs;
    lhs = 0;
    while (tmp_r > 0) {
      lhs += tmp;
      tmp_r -= 1;
    }
    return lhs;
  }
  friend Integer &operator/=(Integer &lhs, Integer const &rhs) {
    Integer tmp = std::move(lhs);
    lhs = 0;
    while (tmp > rhs) {
      tmp -= rhs;
      lhs += 1;
    }
    return lhs;
  }
  friend Integer operator+(Integer const &lhs, Integer const &rhs) {
    Integer ret{lhs};
    ret += rhs;
    return ret;
  }
  friend Integer operator-(Integer const &lhs, Integer const &rhs) {
    Integer ret{lhs};
    ret -= rhs;
    return ret;
  }
  friend Integer operator*(Integer const &lhs, Integer const &rhs) {
    Integer ret{lhs};
    ret *= rhs;
    return ret;
  }
  friend Integer operator/(Integer const &lhs, Integer const &rhs) {
    Integer ret{lhs};
    ret /= rhs;
    return ret;
  }
  friend Integer operator-(Integer const &val) {
    Integer ret = val;
    ret.isNegative = !ret.isNegative;
    return ret;
  }
  friend bool operator<(Integer const &lhs, Integer const &rhs) {
    todo("operator<");
  }
  friend bool operator>(Integer const &lhs, Integer const &rhs) {
    todo("operator>");
  }
  friend bool operator==(Integer const &lhs, Integer const &rhs) {
    todo("operator==");
  }

  friend std::ostream &operator<<(std::ostream &lhs, Integer const &rhs) {
    todo("ostream impl");
    return lhs;
  }
  explicit operator unsigned long() {
    unsigned long ret = 0;
    for (std::size_t i = 0; i < std::min(size, sizeof(unsigned long)); i++) {
      ret += (static_cast<unsigned long>(this->bytes[i]) << (i * 8));
    }
    return ret;
  }
};

int main(void) {
  for (std::size_t i = 0; i <= 8584148901; i++) {
    unsigned long n = i * i;
    n = i + i;
    n = i - i;
    n = i / i;
  }
}