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

// Modified by:
// Massingill, Berna L.
// 2000 Apr 03

// Brain-Dead String Editor Class Implementation

// uses our dll class 

// modified to use dll class's iterator -- see **** comments.

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

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

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

  void forwardCursor(void) {
    if (pos != line.end())
      ++pos;			// ****was:  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;
    }
  }

  // **** must remove "const" from buffer, because begin() and
  //      end() are no longer "const" member functions -- see dll.h
  friend ostream& operator<<(ostream& out, buffer & b) {
    for (dll<char>::iterator p = b.line.begin();
         p != b.line.end();
	 ++p)			// ****was:  p = p->next
      out << *p;		// ****was:  out << p->itm
    return out;
  }

  // Print a line showing the cursor's position.
  // **** must remove "const" from buffer, because begin() and
  //      end() are no longer "const" member functions -- see dll.h
  friend ostream& printCursor(ostream& out, buffer & b) {
    for (dll<char>::iterator p = b.line.begin();
         p != b.pos;
	 ++p)			// ****was:  p = p->next
      out << ' ';

    return out << '^';
  }

private:
  dll<char> line;		// contents of line
  dll<char>::iterator pos;	// points to where characters inserted
                                // and deleted
				// ****was:  dll<char>::link * pos
};