#include "m.h"

static double *qv;

static int compare( const void *ij1, const void *ij2)
{
  int j1, j2;

  j1 = *(double *)ij1;
  j2 = *(double *)ij2;

  if( qv[j1] < qv[j2])
    return -1;

  if( qv[j1] > qv[j2])
    return 1;

  return 0;
}

Symbolptr sort( Symbolptr a)
{
  Symbolptr v;
  int j, count, index;

  index = IO.u.val;

  count = ROWS(a) * COLS(a);

  v = m_create( 1, count);

  if( SCALAR(v)) {
    VAL(v) = index;
    return v;
  }

  for( j = 0; j < count; ++j)
    V(0,j) = j;

  qv = MAT(a)[0];	/* this does not handle possible row pointer swapping... */

  /*
   * v contains indices of a.  qsort() will sort v, not a.
   * The resulting indices can then be used to select elements
   * of a in increasing order.  compare() access a through the
   * static qv pointer.
   */

  qsort( MAT(v)[0], count, sizeof(double), compare);

  if( index != 0)
    for( j = 0; j < count; ++j)	/* fix IO */
      V(0,j) += index;

  return v;
}