--- a/liboctave/idx-vector.h	Thu Oct 30 00:13:05 2008 +0100
+++ b/liboctave/idx-vector.h	Mon Oct 20 16:54:28 2008 +0200
@@ -2,6 +2,7 @@
 
 Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 2000, 2002, 2003,
               2004, 2005, 2006, 2007 John W. Eaton
+Copyright (C) 2008 Jaroslav Hajek
 
 This file is part of Octave.
 
@@ -25,199 +26,382 @@
 #define octave_idx_vector_h 1
 
 #include <iostream>
+#include <algorithm>
+#include <cassert>
 
 #include "dim-vector.h"
 #include "oct-inttypes.h"
-#include "intNDArray.h"
+
+template<class T> class Array;
+class Range;
 
-class ColumnVector;
-class boolNDArray;
-class NDArray;
-class Range;
+// Design rationale:
+// idx_vector is a reference-counting, polymorphic pointer, that can contain
+// 4 types of index objects: a magic colon, a range, a scalar, or an index vector.
+// Polymorphic methods for single element access are provided, as well as
+// templates implementing "early dispatch", i.e. hoisting the checks for index
+// type out of loops.
 
 class
 OCTAVE_API
 idx_vector
 {
+public:
+  
+  enum idx_class_type
+    {
+      class_invalid = -1,
+      class_colon = 0,
+      class_range,
+      class_scalar,
+      class_vector
+    };
+
 private:
 
-  class
-  OCTAVE_API
-  idx_vector_rep
+  class idx_base_rep
+  {
+  public:
+    idx_base_rep (void) : count (1), err (false) { }
+
+    virtual ~idx_base_rep (void) { }
+
+    // Non-range-checking element query.
+    virtual octave_idx_type xelem (octave_idx_type i) const = 0;
+
+    // Range-checking element query.
+    virtual octave_idx_type checkelem (octave_idx_type i) const = 0;
+
+    // Length of the index vector.
+    virtual octave_idx_type length (octave_idx_type n) const = 0;
+
+    // The maximum index + 1. The actual dimension is passed in.
+    virtual octave_idx_type extent (octave_idx_type n) const = 0;
+
+    // Index class.
+    virtual idx_class_type idx_class () const { return class_invalid; }
+
+    // Sorts, maybe uniqifies, and returns a clone object pointer.
+    virtual idx_base_rep *sort_uniq_clone (bool uniq = false) = 0;
+
+    // Checks whether the index is colon or a range equivalent to colon.
+    virtual bool is_colon_equiv (octave_idx_type) const
+      { return false; }
+
+    // The original dimensions of this object (used when subscribing by matrices).
+    virtual dim_vector orig_dimensions () const
+      { return dim_vector (); }
+
+    // i/o
+    virtual std::ostream& print (std::ostream& os) const = 0;
+
+    int count;
+
+    bool err;
+
+  private:
+
+    // No copying!
+    idx_base_rep (const idx_base_rep&);
+  };
+
+  // The magic colon index.
+  class idx_colon_rep : public idx_base_rep
   {
   public:
+    idx_colon_rep (void) { }
 
-    idx_vector_rep (void)
-      : data (0), len (0), num_zeros (0), num_ones (0),
-        range_base (0), range_step (0), max_val (0),
-	min_val (0), count (1), frozen_at_z_len (0), frozen_len (0),
-	colon (0), range(0), initialized (0), frozen (0),
-	colon_equiv_checked (0), colon_equiv (0), orig_dims () { }
+    idx_colon_rep (char c);
+
+    octave_idx_type xelem (octave_idx_type i) const
+      { return i; }
+
+    octave_idx_type checkelem (octave_idx_type i) const;
 
-    idx_vector_rep (const ColumnVector& v);
+    octave_idx_type length (octave_idx_type n) const
+      { return n; }
 
-    idx_vector_rep (const NDArray& nda);
+    octave_idx_type extent (octave_idx_type n) const
+      { return n; }
+
+    idx_class_type idx_class () const { return class_colon; }
 
-    template <class U>
-    idx_vector_rep (const intNDArray<U>& inda)
-      : data (0), len (inda.length ()), num_zeros (0), num_ones (0),
-	range_base (0), range_step (0), max_val (0), min_val (0),
-        count (1), frozen_at_z_len (0), frozen_len (0), colon (0),
-        range(0), initialized (0), frozen (0),
-        colon_equiv_checked (0), colon_equiv (0), orig_dims (inda.dims ())
-    {
-      if (len == 0)
-	{
-	  initialized = 1;
-	  return;
-	}
-      else
-	{
-	  data = new octave_idx_type [len];
+    idx_base_rep *sort_uniq_clone (bool = false) 
+      { count++; return this; }
+
+    bool is_colon_equiv (octave_idx_type) const
+      { return true; }
+
+    std::ostream& print (std::ostream& os) const;
 
-	  for (octave_idx_type i = 0; i < len; i++)
-	    data[i] = tree_to_mat_idx (inda.elem (i));
-	}
-
-      init_state ();
-    }
+  private:
 
-    idx_vector_rep (const Range& r);
-
-    idx_vector_rep (double d);
+    // No copying!
+    idx_colon_rep (const idx_colon_rep& idx);
+  };
 
-    idx_vector_rep (octave_idx_type i);
-
-    idx_vector_rep (char c);
-
-    idx_vector_rep (bool b);
+  // To distinguish the "direct" constructors that blindly trust the data.
+  enum direct { DIRECT };
 
-    template <class U>
-    idx_vector_rep (const octave_int<U>& i)
-      : data (0), len (1), num_zeros (0), num_ones (0),
-	range_base (0), range_step (0), max_val (0), min_val (0),
-        count (1), frozen_at_z_len (0), frozen_len (0), colon (0),
-        range(0), initialized (0), frozen (0),
-        colon_equiv_checked (0), colon_equiv (0), orig_dims (1, 1)
-    {
-      data = new octave_idx_type [len];
-
-      data[0] = tree_to_mat_idx (i);
+  // The integer range index.
+  class idx_range_rep : public idx_base_rep
+  {
+  public:
+    idx_range_rep (octave_idx_type _start, octave_idx_type _len,
+                   octave_idx_type _step, direct) 
+      : idx_base_rep (), start(_start), len(_len), step(_step) { }
 
-      init_state ();
-    }
-
-    idx_vector_rep (const boolNDArray& bnda);
-
-    idx_vector_rep (const idx_vector_rep& a);
+    idx_range_rep (void) 
+      : start(0), len(1), step(1) { }
 
-    ~idx_vector_rep (void) { delete [] data; }
-
-    idx_vector_rep& operator = (const idx_vector_rep& a);
+    // Zero-based constructor.
+    idx_range_rep (octave_idx_type _start, octave_idx_type _limit,
+                   octave_idx_type _step); 
 
-    int ok (void) { return initialized; }
+    idx_range_rep (const Range&);
 
-    octave_idx_type capacity (void) const { return len; }
-    octave_idx_type length (octave_idx_type colon_len) const { return colon ? colon_len : len; }
+    octave_idx_type xelem (octave_idx_type i) const
+      { return start + i * step; }
 
-    octave_idx_type elem (octave_idx_type n) const
-    {
-      return colon ? n : (range ? range_base + range_step*n : data[n]);
-    }
+    octave_idx_type checkelem (octave_idx_type i) const;
+
+    octave_idx_type length (octave_idx_type) const
+      { return len; }
 
-    octave_idx_type checkelem (octave_idx_type n) const;
-    octave_idx_type operator () (octave_idx_type n) const { return checkelem (n); }
+    octave_idx_type extent (octave_idx_type n) const
+      { return std::max (n, (start + 1 + (step < 0 ? 0 : step * (len - 1)))); }
 
-    octave_idx_type max (void) const { return max_val; }
-    octave_idx_type min (void) const { return min_val; }
-
-    octave_idx_type zeros_count (void) const { return num_zeros; }
-    octave_idx_type ones_count (void) const { return num_ones; }
+    idx_class_type idx_class () const { return class_range; }
 
-    int is_colon (void) const { return colon; }
-    int is_colon_equiv (octave_idx_type n, int sort_uniq);
+    idx_base_rep *sort_uniq_clone (bool uniq = false);
 
-    void sort (bool uniq);
-
-    octave_idx_type orig_rows (void) const { return orig_dims(0); }
-    octave_idx_type orig_columns (void) const { return orig_dims(1); }
+    bool is_colon_equiv (octave_idx_type n) const
+      { return start == 0 && step == 1 && len == n; }
 
-    dim_vector orig_dimensions (void) const { return orig_dims; }
-
-    // other stuff
+    dim_vector orig_dimensions () const
+      { return dim_vector (1, len); }
 
-    void shorten (octave_idx_type n); // Unsafe.  Avoid at all cost.
+    octave_idx_type get_start () const { return start; }
 
-    octave_idx_type freeze (octave_idx_type z_len, const char *tag, bool resize_ok);
-
-    // i/o
+    octave_idx_type get_step () const { return step; }
 
     std::ostream& print (std::ostream& os) const;
 
-    octave_idx_type *data;
-    octave_idx_type len;
-    octave_idx_type num_zeros;
-    octave_idx_type num_ones;
-    octave_idx_type range_base;
-    octave_idx_type range_step;
-    octave_idx_type max_val;
-    octave_idx_type min_val;
+  private:
+
+    // No copying!
+    idx_range_rep (const idx_range_rep& idx);
+
+    octave_idx_type start, len, step;
+
+  };
+
+  // The integer scalar index.
+  class idx_scalar_rep : public idx_base_rep
+  {
+  public:
+    idx_scalar_rep (octave_idx_type i, direct)
+      : data (i) { }
+
+    idx_scalar_rep (void)
+      : data (0) { }
+
+    // Zero-based constructor.
+    idx_scalar_rep (octave_idx_type i);
+
+    template <class T>
+    idx_scalar_rep (T x);
+
+    octave_idx_type xelem (octave_idx_type) const
+      { return data; }
+
+    octave_idx_type checkelem (octave_idx_type i) const;
+
+    octave_idx_type length (octave_idx_type) const
+      { return 1; }
+
+    octave_idx_type extent (octave_idx_type n) const
+      { return std::max (n, data + 1); }
+
+    idx_class_type idx_class () const { return class_scalar; }
+
+    idx_base_rep *sort_uniq_clone (bool = false)
+      { count++; return this; }
+
+    bool is_colon_equiv (octave_idx_type n) const
+      { return n == 1 && data == 0; }
+
+    dim_vector orig_dimensions () const
+      { return dim_vector (1, 1); }
+
+    octave_idx_type get_data () const { return data; }
+
+    std::ostream& print (std::ostream& os) const;
+
+  private:
+
+    // No copying!
+    idx_scalar_rep (const idx_scalar_rep& idx);
+
+    octave_idx_type data;
+
+  };
 
-    int count;
+  // The integer vector index.
+  class idx_vector_rep : public idx_base_rep
+  {
+  public:
+    // Direct constructor.
+    idx_vector_rep (octave_idx_type *_data, octave_idx_type _len, 
+                    octave_idx_type _ext, const dim_vector& od, direct)
+      : data (_data), len (_len), ext (_ext), aowner (0), orig_dims (od) { }
+
+    idx_vector_rep (void) 
+      : data (0), len (0), aowner (0)
+      { }
 
-    octave_idx_type frozen_at_z_len;
-    octave_idx_type frozen_len;
+    // Zero-based constructor.
+    idx_vector_rep (const Array<octave_idx_type>& inda);
+
+    template <class T>
+    idx_vector_rep (const Array<T>&);
+
+    idx_vector_rep (bool);
+
+    idx_vector_rep (const Array<bool>&);
+
+    ~idx_vector_rep (void);
+
+    octave_idx_type xelem (octave_idx_type i) const
+      { return data[i]; }
+
+    octave_idx_type checkelem (octave_idx_type i) const;
 
-    unsigned int colon : 1;
-    unsigned int range : 1;
-    unsigned int initialized : 1;
-    unsigned int frozen : 1;
-    unsigned int colon_equiv_checked : 1;
-    unsigned int colon_equiv : 1;
+    octave_idx_type length (octave_idx_type) const
+      { return len; }
+
+    octave_idx_type extent (octave_idx_type n) const
+      { return std::max (n, ext); }
+
+    idx_class_type idx_class () const { return class_vector; }
+
+    idx_base_rep *sort_uniq_clone (bool uniq = false);
+
+    dim_vector orig_dimensions () const
+      { return orig_dims; }
+
+    const octave_idx_type *get_data () const { return data; }
+
+    std::ostream& print (std::ostream& os) const;
+
+  private:
+
+    // No copying!
+    idx_vector_rep (const idx_vector_rep& idx);
+
+    const octave_idx_type *data;
+    octave_idx_type len, ext;
+
+    // This is a trick to allow user-given zero-based arrays to be used as indices
+    // without copying. If the following pointer is nonzero, we do not own the data,
+    // but rather have an Array<octave_idx_type> object that provides us the data.
+    // Note that we need a pointer because we deferred the Array<T> declaration and
+    // we do not want it yet to be defined.
+    
+    Array<octave_idx_type> *aowner;
 
     dim_vector orig_dims;
- 
-    void init_state (void);
+  };
+
+
+  idx_vector (idx_base_rep *r) : rep (r) { }
 
-    octave_idx_type tree_to_mat_idx (double x, bool& conversion_error);
+  // The shared empty vector representation (for fast default constructor)
+  static idx_vector_rep *nil_rep ()
+    {
+      static idx_vector_rep ivr;
+      return &ivr;
+    }
 
-    octave_idx_type tree_to_mat_idx (octave_idx_type i) { return i - 1; }
+  // The shared empty vector representation with the error flag set.
+  static idx_vector_rep *err_rep ()
+    {
+      static idx_vector_rep ivr;
+      ivr.err = true;
+      return &ivr;
+    }
 
-    template <class U> octave_idx_type tree_to_mat_idx (const octave_int<U>& i)
-      { return i.value () - 1; }
-  };
+  // If there was an error in constructing the rep, replace it with empty vector
+  // for safety.
+  void chkerr (void)
+    {
+      if (rep->err)
+        {
+          if (--rep->count == 0)
+            delete rep;
+          rep = err_rep ();
+          rep->count++;
+        }
+    }
 
 public:
 
-  idx_vector (void) : rep (new idx_vector_rep ()) { }
+  // Fast empty constructor.
+  idx_vector (void) : rep (nil_rep ()) { rep->count++; }
 
-  idx_vector (const ColumnVector& v) : rep (new idx_vector_rep (v)) { }
+  // Zero-based constructors (for use from C++).
+  idx_vector (octave_idx_type i) : rep (new idx_scalar_rep (i)) 
+    { chkerr (); }
+
+  idx_vector (octave_idx_type start, octave_idx_type limit,
+              octave_idx_type step = 1)
+    : rep (new idx_range_rep (start, limit, step)) 
+    { chkerr (); }
 
-  idx_vector (const NDArray& nda) : rep (new idx_vector_rep (nda)) { }
+  idx_vector (const Array<octave_idx_type>& inda) 
+    : rep (new idx_vector_rep (inda))
+    { chkerr (); }
 
-  template <class U>
-  idx_vector (const intNDArray<U>& inda) : rep (new idx_vector_rep (inda)) { }
+  // Colon is best constructed by simply copying (or referencing) this member.
+  static const idx_vector colon;
 
-  idx_vector (const Range& r) : rep (new idx_vector_rep (r)) { }
+  // or passing ':' here
+  idx_vector (char c) : rep (new idx_colon_rep (c)) { chkerr (); }
+
+  // Conversion constructors (used by interpreter).
 
-  idx_vector (double d) : rep (new idx_vector_rep (d)) { }
+  template <class T>
+  idx_vector (octave_int<T> x) : rep (new idx_scalar_rep (x)) { chkerr (); }
+
+  idx_vector (double x) : rep (new idx_scalar_rep (x)) { chkerr (); }
 
-  idx_vector (octave_idx_type i) : rep (new idx_vector_rep (i)) { }
+  idx_vector (float x) : rep (new idx_scalar_rep (x)) { chkerr (); }
 
-  idx_vector (char c) : rep (new idx_vector_rep (c)) { }
+  // A scalar bool does not necessarily map to scalar index.
+  idx_vector (bool x) : rep (new idx_vector_rep (x)) { chkerr (); }
 
-  idx_vector (bool b) : rep (new idx_vector_rep (b)) { }
+  template <class T>
+  idx_vector (const Array<octave_int<T> >& nda) : rep (new idx_vector_rep (nda))
+    { chkerr (); }
+
+  idx_vector (const Array<double>& nda) : rep (new idx_vector_rep (nda))
+    { chkerr (); }
 
-  template <class U>
-  idx_vector (const octave_int<U>& i) : rep (new idx_vector_rep (i)) { }
+  idx_vector (const Array<float>& nda) : rep (new idx_vector_rep (nda))
+    { chkerr (); }
 
-  idx_vector (const boolNDArray& bnda) : rep (new idx_vector_rep (bnda)) { }
+  idx_vector (const Array<bool>& nda) : rep (new idx_vector_rep (nda))
+    { chkerr (); }
+
+  idx_vector (const Range& r) 
+    : rep (new idx_range_rep (r))
+    { chkerr (); }
 
   idx_vector (const idx_vector& a) : rep (a.rep) { rep->count++; }
 
   ~idx_vector (void)
     {
-      if (--rep->count <= 0)
+      if (--rep->count == 0)
 	delete rep;
     }
 
@@ -225,7 +409,7 @@
     {
       if (this != &a)
 	{
-	  if (--rep->count <= 0)
+	  if (--rep->count == 0)
 	    delete rep;
 
 	  rep = a.rep;
@@ -234,54 +418,329 @@
       return *this;
     }
 
-  operator bool () const { return rep->ok (); }
+  idx_class_type idx_class (void) const { return rep->idx_class (); }
 
-  octave_idx_type capacity (void) const { return rep->capacity (); }
-  octave_idx_type length (octave_idx_type cl) const { return rep->length (cl); }
+  octave_idx_type length (octave_idx_type n = 0) const 
+    { return rep->length (n); }
 
-  octave_idx_type elem (octave_idx_type n) const { return rep->elem (n); }
-  octave_idx_type checkelem (octave_idx_type n) const { return rep->checkelem (n); }
-  octave_idx_type operator () (octave_idx_type n) const { return rep->operator () (n); }
+  octave_idx_type extent (octave_idx_type n) const 
+    { return rep->extent (n); }
 
-  octave_idx_type max (void) const { return rep->max (); }
-  octave_idx_type min (void) const { return rep->min (); }
+  octave_idx_type xelem (octave_idx_type n) const 
+    { return rep->xelem (n); }
+
+  octave_idx_type checkelem (octave_idx_type n) const 
+    { return rep->checkelem (n); }
 
-  int one_zero_only (void) const { return 0; }
-  octave_idx_type zeros_count (void) const { return rep->zeros_count (); }
-  octave_idx_type ones_count (void) const { return rep->ones_count (); }
+  octave_idx_type operator () (octave_idx_type n) const 
+    {
+#if defined (BOUNDS_CHECKING)
+      return rep->checkelem (n); 
+#else
+      return rep->xelem (n);
+#endif
+    }
+
+  operator bool () const
+    { return ! rep->err; }
 
-  int is_colon (void) const { return rep->is_colon (); }
-  int is_colon_equiv (octave_idx_type n, int sort_uniq = 0) const
-    { return rep->is_colon_equiv (n, sort_uniq); }
+  bool is_colon (void) const 
+    { return rep->idx_class () == class_colon; }
+
+  bool is_scalar (void) const 
+    { return rep->idx_class () == class_scalar; }
 
-  void sort (bool uniq = false) { rep->sort (uniq); }
+  bool is_colon_equiv (octave_idx_type n) const
+    { return rep->is_colon_equiv (n); }
 
-  octave_idx_type orig_rows (void) const { return rep->orig_rows (); }
-  octave_idx_type orig_columns (void) const { return rep->orig_columns (); }
+  idx_vector sorted (bool uniq = false) const
+    { return idx_vector (rep->sort_uniq_clone (uniq)); }
 
   dim_vector orig_dimensions (void) const { return rep->orig_dimensions (); }
 
+  octave_idx_type orig_rows () const
+    { return orig_dimensions () (0); }
+
+  octave_idx_type orig_columns () const
+    { return orig_dimensions () (1); }
+
   int orig_empty (void) const
     { return (! is_colon () && orig_dimensions().any_zero ()); }
 
-  // Unsafe.  Avoid at all cost.
-  void shorten (octave_idx_type n) { rep->shorten (n); }
-
   // i/o
 
-  octave_idx_type freeze (octave_idx_type z_len, const char *tag, bool resize_ok = false)
-    { return rep->freeze (z_len, tag, resize_ok); }
-
   std::ostream& print (std::ostream& os) const { return rep->print (os); }
 
   friend std::ostream& operator << (std::ostream& os, const idx_vector& a)
     { return a.print (os); }
 
+  // Slice with specializations. No checking of bounds!
+  //
+  // This is equivalent to the following loop (but much faster):
+  //
+  // for (octave_idx_type i = 0; i < idx->length (n); i++)
+  //   dest[i] = src[idx(i)];
+  // return i;
+  //
+  template <class T>
+  octave_idx_type
+  index (const T *src, octave_idx_type n, T *dest) const
+    {
+      octave_idx_type len = rep->length (n);
+      switch (rep->idx_class ())
+        {
+        case class_colon:
+          std::copy (src, src + len, dest);
+          break;
+        case class_range:
+          {
+            idx_range_rep * r = dynamic_cast<idx_range_rep *> (rep);
+            octave_idx_type start = r->get_start (), step = r->get_step ();
+            const T *ssrc = src + start;
+            if (step == 1)
+              std::copy (ssrc, ssrc + len, dest);
+            else if (step == -1)
+              std::reverse_copy (ssrc - len + 1, ssrc + 1, dest);
+            else
+              {
+                for (octave_idx_type i = 0, j = 0; i < len; i++, j += step)
+                  dest[i] = ssrc[j];
+              }
+          }
+          break;
+        case class_scalar:
+          {
+            idx_scalar_rep * r = dynamic_cast<idx_scalar_rep *> (rep);
+            dest[0] = src[r->get_data ()];
+          }
+          break;
+        case class_vector:
+          {
+            idx_vector_rep * r = dynamic_cast<idx_vector_rep *> (rep);
+            const octave_idx_type *data = r->get_data ();
+            for (octave_idx_type i = 0; i < len; i++)
+              dest[i] = src[data[i]];
+          }
+          break;
+        default:
+          assert (false);
+          break;
+        }
+
+      return len;
+    }
+
+  // Slice assignment with specializations. No checking of bounds!
+  //
+  // This is equivalent to the following loop (but much faster):
+  //
+  // for (octave_idx_type i = 0; i < idx->length (n); i++)
+  //   dest[idx(i)] = src[i];
+  // return i;
+  //
+  template <class T>
+  octave_idx_type
+  assign (const T *src, octave_idx_type n, T *dest) const
+    {
+      octave_idx_type len = rep->length (n);
+      switch (rep->idx_class ())
+        {
+        case class_colon:
+          std::copy (src, src + len, dest);
+          break;
+        case class_range:
+          {
+            idx_range_rep * r = dynamic_cast<idx_range_rep *> (rep);
+            octave_idx_type start = r->get_start (), step = r->get_step ();
+            T *sdest = dest + start;
+            if (step == 1)
+              std::copy (src, src + len, sdest);
+            else if (step == -1)
+              std::reverse_copy (src, src + len, sdest - len + 1);
+            else
+              {
+                for (octave_idx_type i = 0, j = 0; i < len; i++, j += step)
+                  sdest[j] = src[i];
+              }
+          }
+          break;
+        case class_scalar:
+          {
+            idx_scalar_rep * r = dynamic_cast<idx_scalar_rep *> (rep);
+            dest[r->get_data ()] = src[0];
+          }
+          break;
+        case class_vector:
+          {
+            idx_vector_rep * r = dynamic_cast<idx_vector_rep *> (rep);
+            const octave_idx_type *data = r->get_data ();
+            for (octave_idx_type i = 0; i < len; i++)
+              dest[data[i]] = src[i];
+          }
+          break;
+        default:
+          assert (false);
+          break;
+        }
+
+      return len;
+    }
+
+  // Slice fill with specializations. No checking of bounds!
+  //
+  // This is equivalent to the following loop (but much faster):
+  //
+  // for (octave_idx_type i = 0; i < idx->length (n); i++)
+  //   dest[idx(i)] = val;
+  // return i;
+  //
+  template <class T>
+  octave_idx_type
+  fill (const T& val, octave_idx_type n, T *dest) const
+    {
+      octave_idx_type len = rep->length (n);
+      switch (rep->idx_class ())
+        {
+        case class_colon:
+          std::fill (dest, dest + len, val);
+          break;
+        case class_range:
+          {
+            idx_range_rep * r = dynamic_cast<idx_range_rep *> (rep);
+            octave_idx_type start = r->get_start (), step = r->get_step ();
+            T *sdest = dest + start;
+            if (step == 1)
+              std::fill (sdest, sdest + len, val);
+            else if (step == -1)
+              std::fill (sdest - len + 1, sdest + 1, val);
+            else
+              {
+                for (octave_idx_type i = 0, j = 0; i < len; i++, j += step)
+                  sdest[j] = val;
+              }
+          }
+          break;
+        case class_scalar:
+          {
+            idx_scalar_rep * r = dynamic_cast<idx_scalar_rep *> (rep);
+            dest[r->get_data ()] = val;
+          }
+          break;
+        case class_vector:
+          {
+            idx_vector_rep * r = dynamic_cast<idx_vector_rep *> (rep);
+            const octave_idx_type *data = r->get_data ();
+            for (octave_idx_type i = 0; i < len; i++)
+              dest[data[i]] = val;
+          }
+          break;
+        default:
+          assert (false);
+          break;
+        }
+
+      return len;
+    }
+
+  // Generic breakable indexed loop. The loop body should be encapsulated in a
+  // single functor body. 
+  // This is equivalent to the following loop (but faster, at least for simple
+  // inlined bodies):
+  //
+  // for (octave_idx_type i = 0; i < idx->length (n); i++)
+  //   if (body (i, idx(i))) break;
+  // return i;
+  // 
+
+  template <class Functor>
+  octave_idx_type
+  loop (octave_idx_type n, const Functor& body) const
+    {
+      octave_idx_type len = rep->length (n), ret;
+      switch (rep->idx_class ())
+        {
+        case class_colon:
+          {
+            octave_idx_type i;
+            for (i = 0; i < len && body (i); i++) ;
+            ret = i;
+          }
+          break;
+        case class_range:
+          {
+            idx_range_rep * r = dynamic_cast<idx_range_rep *> (rep);
+            octave_idx_type start = r->get_start (), step = r->get_step ();
+            octave_idx_type i, j;
+            if (step == 1)
+              for (i = start, j = start + len; i < j && body (i); i++) ;
+            else if (step == -1)
+              for (i = start, j = start - len; i > j && body (i); i--) ;
+            else
+              for (i = 0, j = start; i < len && body (j); i++, j += step) ;
+            ret = i;
+          }
+          break;
+        case class_scalar:
+          {
+            idx_scalar_rep * r = dynamic_cast<idx_scalar_rep *> (rep);
+            ret = body (r->get_data ()) ? 1 : 0;
+          }
+          break;
+        case class_vector:
+          {
+            idx_vector_rep * r = dynamic_cast<idx_vector_rep *> (rep);
+            octave_idx_type *data = r->get_data ();
+            octave_idx_type i;
+            for (i = 0; i < len && body (data[i]); i++) ;
+            ret = i;
+          }
+          break;
+        default:
+          assert (false);
+          break;
+        }
+
+      return ret;
+    }
+
+  // Rationale: 
+  // This method is the key to "smart indexing". When indexing cartesian
+  // arrays, sometimes consecutive index vectors can be reduced into a single
+  // index. If rows (A) = k and i.maybe_reduce (j) gives k, then A(i,j)(:) is
+  // equal to A(k)(:).
+
+  // If the next index can be reduced, returns true and updates this.
+  bool maybe_reduce (octave_idx_type n, const idx_vector& j,
+                     octave_idx_type nj);
+
+  bool is_cont_range (octave_idx_type n,
+                      octave_idx_type& l, octave_idx_type& u) const;
+
+  idx_vector
+  complement (octave_idx_type n) const;
+
+  // FIXME: These are here for compatibility. They should be removed when no
+  // longer in use.
+
+  octave_idx_type elem (octave_idx_type n) const 
+    { return (*this) (n); }
+
+  bool is_colon_equiv (octave_idx_type n, int) const
+    { return is_colon_equiv (n); }
+
+  octave_idx_type freeze (octave_idx_type z_len, const char *tag, bool resize_ok = false);
+
+  void sort (bool uniq = false)
+    { *this = sorted (uniq); }
+
+  octave_idx_type ones_count () const;
+
+  octave_idx_type max () const { return extent (1) - 1; }
+  
 private:
 
-  idx_vector_rep *rep;
+  idx_base_rep *rep;
 
-  void init_state (void) { rep->init_state (); }
 };
 
 #endif