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


// adds a value to the set.  returns true on success (space available)
// and false on failure (set full)
bool IntSet::add (int value) {

  if (count == MAXVALUES) return false;

  data[count++] = value;
  walkInProgress = false; // scrub any ongoing walk
  return true;

}


// removes the specfied value from the set.  returns
// true on success (value existed) and false on failure (value did not exist)
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;

}


// returns the number of times that the specified value occurs in the set
int IntSet::countOccurrences (int value) const {

  int i, occurrences = 0;

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

  return occurrences;

}


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;

}