/*
 * This file is part of libdyn.a, the C Dynamic Object library.  It
 * contains the source code for the function DynInsert().
 * 
 * There are no restrictions on this code; however, if you make any
 * changes, I request that you document them so that I do not get
 * credit or blame for your modifications.
 *
 * Written by Barr3y Jaspan, Student Information Processing Board (SIPB)
 * and MIT-Project Athena, 1989.
 */

#include "dynP.h"

int
DynInsert(DynObject obj,
	  int idx,
	  DynPtr els,
	  int num)
     
{
     int ret;
     
     if (idx < 0 || idx > obj->num_el) {
	  if (obj->debug)
	       fprintf(stderr, "dyn: insert: index %d is not in [0,%d]\n",
		       idx, obj->num_el);
	  return DYN_BADINDEX;
     }

     if (num < 1) {
	  if (obj->debug)
	       fprintf(stderr, "dyn: insert: cannot insert %d elements\n",
		       num);
	  return DYN_BADVALUE;
     }

     if (obj->debug)
	  fprintf(stderr,"dyn: insert: Moving %d bytes from %p + %d to + %d\n",
		  (obj->num_el-idx)*obj->el_size, obj->array,
		  obj->el_size*idx, obj->el_size*(idx+num));

     if ((ret = _DynResize(obj, obj->num_el + num)) != DYN_OK)
	  return ret;

     (void) memmove(obj->array + (idx + num), obj->array + idx, 
		    (obj->num_el-idx)*obj->el_size);

     if (obj->debug)
	  fprintf(stderr, "dyn: insert: Copying %d bytes from %p to %p + %d\n",
		  obj->el_size*num, els, obj->array, obj->el_size*idx);

     (void) memmove(obj->array + obj->el_size*idx, els, obj->el_size*num);

     obj->num_el += num;

     if (obj->debug)
	  fprintf(stderr, "dyn: insert: done.\n");

     return DYN_OK;
}