// Oldham, Jeffrey D.
// 2000Mar13
// CS1321

// Brain-Dead String Editor Class Implementation

// uses our dll class (and an iterator)

#include "dll.h"
#include <iostream>

class buffer {
public:
  buffer(void) { pos = line.end(); }

  void backCursor(void) {
    if (pos != line.begin())
      pos = pos->prev;		// 
    return;
  }

  void forwardCursor(void) {
    if (pos != line.end())
      pos = pos->next;		// 
  }

  void deleteChar(void) {
    if (pos != line.end())
      pos = line.erase(pos);
  }

  void insertChars(const string & s) {
    if (s.empty())
      return;
    else {
      line.insert(pos, s[0]);
      insertChars(s.substr(1));
      return;
    }
  }

  friend ostream& operator<<(ostream& out, const buffer & b) {
    for (dll::link * p = b.line.begin();
	 p != b.line.end();
	 p = p->next)		// 
      out << p->itm;
    return out;
  }

  // Print a line showing the cursor's position.
  friend ostream& printCursor(ostream& out, const buffer & b) {
    for (dll::link * p = b.line.begin();
	 p != b.pos;
	 p = p->next)		// 
      out << ' ';

    return out << '^';
  }

private:
  dll line;			// contents of line
  dll::link * pos;		// points to where characters inserted 
				// and deleted
};