# HG changeset patch
# User alpar
# Date 1163497766 0
# Node ID 005b3f927287186ddef9b71eb24020c4f57e9a7b
# Parent  d3c664c975eef0a3a8ca4e2e853316cf09c502dd
ColIt added. (Untested, but at least it compiles.)

diff -r d3c664c975ee -r 005b3f927287 lemon/lp_base.h
--- a/lemon/lp_base.h	Mon Nov 13 18:58:39 2006 +0000
+++ b/lemon/lp_base.h	Tue Nov 14 09:49:26 2006 +0000
@@ -39,11 +39,12 @@
   class _FixId 
   {
   protected:
+    int _first_index;
+    int first_free;
+  public:
     std::vector<int> index;
     std::vector<int> cross;
-    int first_free;
-  public:
-    _FixId() : first_free(-1) {};
+    _FixId() : _first_index(-1), first_free(-1) {};
     ///Convert a floating id to a fix one
 
     ///\param n is a floating id
@@ -61,6 +62,7 @@
     ///\todo Multiple additions should also be handled.
     int insert(int n)
     {
+      if(cross.empty()) _first_index=n;
       if(n>=int(cross.size())) {
 	cross.resize(n+1);
 	if(first_free==-1) {
@@ -101,6 +103,11 @@
     ///
     std::size_t maxFixId() { return cross.size()-1; }
   
+    ///Returns the first (smallest) inserted index
+
+    ///Returns the first (smallest) inserted index
+    ///or -1 if no index has been inserted before.
+    int firstIndex() {return _first_index;}
   };
     
   ///Common base class for LP solvers
@@ -109,6 +116,10 @@
   ///\ingroup gen_opt_group
   class LpSolverBase {
 
+  protected:
+    _FixId rows;
+    _FixId cols;
+
   public:
 
     ///Possible outcomes of an LP solving procedure
@@ -164,6 +175,10 @@
 
     static inline bool isNaN(const Value& v) { return v!=v; }
     
+    friend class Col;
+    friend class ColIt;
+    friend class Row;
+    
     ///Refer to a column of the LP.
 
     ///This type is used to refer to a column of the LP.
@@ -189,6 +204,23 @@
       bool operator!=(Col c) const  {return id!=c.id;}
     };
 
+    class ColIt : public Col {
+      LpSolverBase *_lp;
+      ColIt() {}
+      ColIt(LpSolverBase &lp) : _lp(&lp)
+      {
+	id = _lp->cols.cross.empty()?-1:
+	  _lp->cols.fixId(_lp->cols.firstIndex());
+      }
+      ColIt(const Invalid&) : Col(INVALID) {}
+      ColIt &operator++() 
+      {
+	int fid = _lp->cols.floatingId(id)+1;
+	id = unsigned(fid)<_lp->cols.cross.size() ? _lp->cols.fixId(fid) : -1;
+	return *this;
+      }
+    };
+      
     ///Refer to a row of the LP.
 
     ///This type is used to refer to a row of the LP.
@@ -564,8 +596,6 @@
     
 
   protected:
-    _FixId rows;
-    _FixId cols;
 
     //Abstract virtual functions
     virtual LpSolverBase &_newLp() = 0;
@@ -579,7 +609,7 @@
     };
 
     virtual int _addCol() = 0;
-    virtual int _addRow() = 0;
+    virtual int _addRow() = 0; 
     virtual void _eraseCol(int col) = 0;
     virtual void _eraseRow(int row) = 0;
     virtual void _getColName(int col,       std::string & name) = 0;