Computational routine
eng

##
time_delay

### File content

    #include "scicos_block.h"
    #include <math.h>
    #include "../machine.h"

    #if WIN32
    #define NULL    0
    #endif

    extern void sciprint __PARAMS((char *fmt,...));

    void time_delay(scicos_block *block,int flag)
    {/*  rpar[0]=delay, rpar[1]=init value, ipar[0]=buffer length */
      double* pw,del,t,td,eps;
      int* iw;
      int i,j,k;
      if (flag == 4){/* the workspace is used to store previous values */
        if ((*block->work=
    	 scicos_malloc(sizeof(int)+sizeof(double)*
    		       block->ipar[0]*(1+block->insz[0])))== NULL ) {
          set_block_error(-16);
          return;
        }
        eps=1.0e-9; /* shift times to left to avoid replacing 0 */
        pw=*block->work;
        pw[0]=-block->rpar[0]*(block->ipar[0]-1)-eps;
        for(j=1;j< block->insz[0]+1;j++){
    	pw[block->ipar[0]*j]=block->rpar[1];
        }

        for(i=1;i< block->ipar[0];i++){
          pw[i]=pw[i-1]+block->rpar[0]-eps;
          for(j=1;j< block->insz[0]+1;j++){
    	pw[i+block->ipar[0]*j]=block->rpar[1];
          }
        }

        iw=(int *)(pw+block->ipar[0]*(1+block->insz[0]));
        *iw=0;
        for (k=0;k<block->insz[0];k++){
    	block->outptr[0][k]=block->rpar[1];
        }
      }else  if (flag == 5){
        scicos_free(*block->work);

      } else if (flag==0||flag==2) {
        if (flag==2) do_cold_restart();
        pw=*block->work;
        iw=(int *)(pw+block->ipar[0]*(1+block->insz[0]));
        t=get_scicos_time();
        td=t-block->rpar[0];
        if(td<pw[*iw]){
          sciprint("delayed time=%f but last stored time=%f \r\n", td, pw[*iw]);
          sciprint("Consider increasing the length of buffer in delay block \r\n");
        }

        if (t>pw[(block->ipar[0]+*iw-1)%block->ipar[0]]){
          for(j=1;j< block->insz[0]+1;j++){
    	pw[*iw +block->ipar[0]*j]=block->inptr[0][j-1];
          }
          pw[*iw]=t;
          /*sciprint("**time is %f. I put %f, in %d \r\n", t,block->inptr[0][0],*iw);*/
          *iw=(*iw+1)%block->ipar[0];

        }else{
          for(j=1;j< block->insz[0]+1;j++){
    	pw[(block->ipar[0]+*iw-1)%block->ipar[0] +block->ipar[0]*j]=block->inptr[0][j-1];
          }
          pw[(block->ipar[0]+*iw-1)%block->ipar[0]]=t;
          /*sciprint("**time is %f. I put %f, in %d \r\n", t,block->inptr[0][0],*iw);*/

        }

      } else if (flag==1) {
        pw=*block->work;
        iw=(int *) (pw+block->ipar[0]*(1+block->insz[0]));
        t=get_scicos_time();
        td=t-block->rpar[0];

        i=0;j= block->ipar[0]-1;

        while (j-i>1) {
          k=(i+j)/2;
          if (td<pw[(k+*iw)%block->ipar[0]]) {
    	j=k;
          }else if (td>pw[(k+*iw)%block->ipar[0]]) {
    	i=k;
          }else{
    	i=k;
    	j=k;
    	break;
          }
        }
        i=(i+*iw)%block->ipar[0];
        j=(j+*iw)%block->ipar[0];
        del=pw[j]-pw[i];
        /*    sciprint("time is %f. interpolating %d and %d, i.e. %f, %f\r\n", t,i,j,pw[i],pw[j]);
    	  sciprint("values are  %f   %f.\r\n",pw[i+block->ipar[0]],pw[j+block->ipar[0]]);*/
        if(del!=0.0){
          for (k=1;k<block->insz[0]+1;k++){
    	block->outptr[0][k-1]=((pw[j]-td)*pw[i+block->ipar[0]*k] +
    			       (td-pw[i])*pw[j+block->ipar[0]*k])/del;
          }
        }else{
          for (k=1;k<block->insz[0]+1;k++){
    	block->outptr[0][k-1]=pw[i+block->ipar[0]*k];
          }
        }
      }
    }