#include "stdstuff.h"
#include "IntSet.h"


void IntSet::add (int value) {

  if (valueExists(value)) return; // value already in set

  if (count == MAXVALUES) {
    throw overflow_error ("IntSet::add - set overflow");
  }
  data[count++] = value;
  walkInProgress = false; // scrub any ongoing walk
  return;

}


bool IntSet::remove (int value) {

  int i;

  for (i = 0; i < count; i++) {
    if (data[i] == value) {
      // we've found the data value.
      // overwrite it with the last data value and adjust the count
      // to reflect the fact that there are now one fewer values in
      // the set.  note that this works even if the value being removed
      // is the last value in the set.
      data[i] = data[--count];
      walkInProgress = false; // scrub any ongoing walk
      return true;
    }
  }

  return false;

}


void IntSet::removeAll () {

  count = 0; walkInProgress = false;

}


bool IntSet::valueExists (int value) const {

  int i;

  for (i = 0; i < count; i++) {
    if (data[i] == value) {
      return true;
    }
  }

  // value not found
  return false;

}


bool IntSet::startWalk (int &value) {

  if (count == 0) return false;

  walkInProgress = true; walkPosition = 0;
  value = data[walkPosition];
  return true;

}


bool IntSet::continueWalk (int &value) {

  if (!walkInProgress) {
    throw range_error ("IntSet::continueWalk invalid call");
  }
  if (++walkPosition == count) {
    walkInProgress = false; // we've come to the end of the road
    return false;
  }
  value = data[walkPosition];
  return true;

}


bool IntSet::operator== (const IntSet &otherSet) const {

  int i;

  // if the sets have different sizes, they aren't equal
  if (count != otherSet.count) return false;

  // the sets have the same size.  if all of the values in one of
  // them are in the other, they are equal.  if any of the values in
  // one set is not in the other set, they are not equal.
  for (i = 0; i < count; i++) {
    if (!otherSet.valueExists(data[i])) return false;
  }
  return true;

}


IntSet IntSet::intersect (const IntSet &otherSet) const {

  IntSet result;
  int i;

  for (i = 0; i < count; i++) { // go through values in implicit set
    if (otherSet.valueExists(data[i])) { // if value also exists in other set, put it in result
      result.add(data[i]);
    }
  }

  return result;

}


IntSet IntSet::unionWith (const IntSet &otherSet) const {

  IntSet result = otherSet; // start with otherSet
  int i;

  for (i = 0; i < count; i++) { // add all values from implicit set
    result.add(data[i]);
  }

  return result;

}