/*
 * C/Matlab/mex replacement for FSM_inc.m
 *
 * FSM_inc( x, n) - increment x, base n
 * where x is an index row vector containing values in the range 1..n
 *
 * Note that unlike FSM_inc.m, this routine increments x directly
 * and does not return a separate vector result.
 *
 * A test using isi_t/get_ML.m with N=13 shows that use of FSM_inc_C.c
 * decreases the runtime by about 7% compared to FSM_inc.m
 *
 * R. Perry, 9 June 2000
 */

#include "mex.h"		/* for Matlab/mex stuff */

static int MN;			/* result size */

static double *x;		/* arguments */
static double n;

static void FSM_inc( void)
{
  double *px = x + MN;
  double s, c = 1.0;

  while( px > x) {

    --px;

    s = c + *px;

    if( s > n) {
      c = 1.0;
      *px = 1.0;
    } else {
      *px = s;
      break;
    }

  }
}

void mexFunction( int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
/* get rhs */

  if( nrhs != 2)
    mexErrMsgTxt("two arguments required");

  x = mxGetPr( prhs[0]);

  n = mxGetScalar( prhs[1]);

  MN = mxGetM(prhs[0]) * mxGetN(prhs[0]);

/* doit */

  FSM_inc();
}