qset.c

关于网格剖分的

      return SETelem_(set, set->maxsize - 1);
    else if (size > 1)
      return SETelem_(set, size - 2);
  }
  return NULL;
} /* setlast */


/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="setnew">-</a>
  
  qh_setnew( setsize )
    creates and allocates space for a set

  notes:
    setsize means the number of elements (NOT including the NULL terminator)
    use qh_settemp/qh_setfreetemp if set is temporary

  design:
    allocate memory for set
    roundup memory if small set
    initialize as empty set
*/
setT *qh_setnew(int setsize) {
  setT *set;
  int sizereceived; /* used !qh_NOmem */
  int size;
  void **freelistp; /* used !qh_NOmem */

  if (!setsize)
    setsize++;
  size= sizeof(setT) + setsize * SETelemsize;
  if ((unsigned) size <= (unsigned) qhmem.LASTsize) {
    qh_memalloc_(size, freelistp, set, setT);
#ifndef qh_NOmem
    sizereceived= qhmem.sizetable[ qhmem.indextable[size]];
    if (sizereceived > size) 
      setsize += (sizereceived - size)/SETelemsize;
#endif
  }else
    set= (setT*)qh_memalloc (size);
  set->maxsize= setsize;
  set->e[setsize].i= 1;
  set->e[0].p= NULL;
  return (set);
} /* setnew */


/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="setnew_delnthsorted">-</a>
  
  qh_setnew_delnthsorted( set, size, nth, prepend )
    creates a sorted set not containing nth element
    if prepend, the first prepend elements are undefined

  notes:
    set must be defined
    checks nth
    see also: setdelnthsorted

  design:
    create new set
    setup pointers and allocate room for prepend'ed entries
    append head of old set to new set
    append tail of old set to new set
*/
setT *qh_setnew_delnthsorted(setT *set, int size, int nth, int prepend) {
  setT *newset;
  void **oldp, **newp;
  int tailsize= size - nth -1, newsize;

  if (tailsize < 0) {
    fprintf (qhmem.ferr, "qhull internal error (qh_setaddnth): nth %d is out-of-bounds for set:\n", nth);
    qh_setprint (qhmem.ferr, "", set);
    qh_errexit (qhmem_ERRqhull, NULL, NULL);
  }
  newsize= size-1 + prepend;
  newset= qh_setnew(newsize);
  newset->e[newset->maxsize].i= newsize+1;  /* may be overwritten */
  oldp= SETaddr_(set, void);
  newp= SETaddr_(newset, void) + prepend;
  switch (nth) {
  case 0:
    break;
  case 1:
    *(newp++)= *oldp++;
    break;
  case 2:
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    break;
  case 3:
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    break;
  case 4:
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    break;
  default:
    memcpy((char *)newp, (char *)oldp, nth * SETelemsize);
    newp += nth;
    oldp += nth;
    break;
  }
  oldp++;
  switch (tailsize) {
  case 0:
    break;
  case 1:
    *(newp++)= *oldp++;
    break;
  case 2:
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    break;
  case 3:
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    break;
  case 4:
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    *(newp++)= *oldp++;
    break;
  default:
    memcpy((char *)newp, (char *)oldp, tailsize * SETelemsize);
    newp += tailsize;
  }
  *newp= NULL;
  return(newset);
} /* setnew_delnthsorted */


/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="setprint">-</a>
  
  qh_setprint( fp, string, set )
    print set elements to fp with identifying string

  notes:
    never errors
*/
void qh_setprint(FILE *fp, char* string, setT *set) {
  int size, k;

  if (!set)
    fprintf (fp, "%s set is null\n", string);
  else {
    SETreturnsize_(set, size);
    fprintf (fp, "%s set=%p maxsize=%d size=%d elems=",
	     string, set, set->maxsize, size);
    if (size > set->maxsize)
      size= set->maxsize+1;
    for (k=0; k < size; k++)
      fprintf(fp, " %p", set->e[k].p);
    fprintf(fp, "\n");
  }
} /* setprint */

/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="setreplace">-</a>
  
  qh_setreplace( set, oldelem, newelem )
    replaces oldelem in set with newelem

  notes:
    errors if oldelem not in the set
    newelem may be NULL, but it turns the set into an indexed set (no FOREACH)

  design:
    find oldelem
    replace with newelem
*/
void qh_setreplace(setT *set, void *oldelem, void *newelem) {
  void **elemp;
  
  elemp= SETaddr_(set, void);
  while(*elemp != oldelem && *elemp)
    elemp++;
  if (*elemp)
    *elemp= newelem;
  else {
    fprintf (qhmem.ferr, "qhull internal error (qh_setreplace): elem %p not found in set\n",
       oldelem);
    qh_setprint (qhmem.ferr, "", set);
    qh_errexit (qhmem_ERRqhull, NULL, NULL);
  }
} /* setreplace */


/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="setsize">-</a>
  
  qh_setsize( set )
    returns the size of a set

  notes:
    errors if set's maxsize is incorrect
    same as SETreturnsize_(set)

  design:
    determine actual size of set from maxsize
*/
int qh_setsize(setT *set) {
  int size, *sizep;
  
  if (!set)
    return (0);
  sizep= SETsizeaddr_(set);
  if ((size= *sizep)) {
    size--;
    if (size > set->maxsize) {
      fprintf (qhmem.ferr, "qhull internal error (qh_setsize): current set size %d is greater than maximum size %d\n",
	       size, set->maxsize);
      qh_setprint (qhmem.ferr, "set: ", set);
      qh_errexit (qhmem_ERRqhull, NULL, NULL);
    }
  }else
    size= set->maxsize;
  return size;
} /* setsize */

/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="settemp">-</a>
  
  qh_settemp( setsize )
    return a stacked, temporary set of upto setsize elements

  notes:
    use settempfree or settempfree_all to release from qhmem.tempstack
    see also qh_setnew

  design:
    allocate set
    append to qhmem.tempstack
    
*/
setT *qh_settemp(int setsize) {
  setT *newset;
  
  newset= qh_setnew (setsize);
  qh_setappend ((setT **)&qhmem.tempstack, newset);
  if (qhmem.IStracing >= 5)
    fprintf (qhmem.ferr, "qh_settemp: temp set %p of %d elements, depth %d\n",
       newset, newset->maxsize, qh_setsize ((setT*)qhmem.tempstack));
  return newset;
} /* settemp */

/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="settempfree">-</a>
  
  qh_settempfree( set )
    free temporary set at top of qhmem.tempstack

  notes:
    nop if set is NULL
    errors if set not from previous   qh_settemp
  
  to locate errors:
    use 'T2' to find source and then find mis-matching qh_settemp

  design:
    check top of qhmem.tempstack
    free it
*/
void qh_settempfree(setT **set) {
  setT *stackedset;

  if (!*set)
    return;
  stackedset= qh_settemppop ();
  if (stackedset != *set) {
    qh_settemppush(stackedset);
    fprintf (qhmem.ferr, "qhull internal error (qh_settempfree): set %p (size %d) was not last temporary allocated (depth %d, set %p, size %d)\n",
	     *set, qh_setsize(*set), qh_setsize((setT*)qhmem.tempstack)+1,
	     stackedset, qh_setsize(stackedset));
    qh_errexit (qhmem_ERRqhull, NULL, NULL);
  }
  qh_setfree (set);
} /* settempfree */

/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="settempfree_all">-</a>
  
  qh_settempfree_all(  )
    free all temporary sets in qhmem.tempstack

  design:
    for each set in tempstack
      free set
    free qhmem.tempstack
*/
void qh_settempfree_all(void) {
  setT *set, **setp;

  FOREACHset_((setT *)qhmem.tempstack) 
    qh_setfree(&set);
  qh_setfree((setT **)&qhmem.tempstack);
} /* settempfree_all */

/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="settemppop">-</a>
  
  qh_settemppop(  )
    pop and return temporary set from qhmem.tempstack 

  notes:
    the returned set is permanent
    
  design:
    pop and check top of qhmem.tempstack
*/
setT *qh_settemppop(void) {
  setT *stackedset;
  
  stackedset= (setT*)qh_setdellast((setT *)qhmem.tempstack);
  if (!stackedset) {
    fprintf (qhmem.ferr, "qhull internal error (qh_settemppop): pop from empty temporary stack\n");
    qh_errexit (qhmem_ERRqhull, NULL, NULL);
  }
  if (qhmem.IStracing >= 5)
    fprintf (qhmem.ferr, "qh_settemppop: depth %d temp set %p of %d elements\n",
       qh_setsize((setT*)qhmem.tempstack)+1, stackedset, qh_setsize(stackedset));
  return stackedset;
} /* settemppop */

/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="settemppush">-</a>
  
  qh_settemppush( set )
    push temporary set unto qhmem.tempstack (makes it temporary)

  notes:
    duplicates settemp() for tracing

  design:
    append set to tempstack  
*/
void qh_settemppush(setT *set) {
  
  qh_setappend ((setT**)&qhmem.tempstack, set);
  if (qhmem.IStracing >= 5)
    fprintf (qhmem.ferr, "qh_settemppush: depth %d temp set %p of %d elements\n",
    qh_setsize((setT*)qhmem.tempstack), set, qh_setsize(set));
} /* settemppush */

 
/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="settruncate">-</a>
  
  qh_settruncate( set, size )
    truncate set to size elements

  notes:
    set must be defined

  design:
    check size
    update actual size of set
*/
void qh_settruncate (setT *set, int size) {

  if (size < 0 || size > set->maxsize) {
    fprintf (qhmem.ferr, "qhull internal error (qh_settruncate): size %d out of bounds for set:\n", size);
    qh_setprint (qhmem.ferr, "", set);
    qh_errexit (qhmem_ERRqhull, NULL, NULL);
  }
  set->e[set->maxsize].i= size+1;   /* maybe overwritten */
  set->e[size].p= NULL;
} /* settruncate */
    
/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="setunique">-</a>
  
  qh_setunique( set, elem )
    add elem to unsorted set unless it is already in set

  notes:
    returns 1 if it is appended

  design:
    if elem not in set
      append elem to set
*/
int qh_setunique (setT **set, void *elem) {

  if (!qh_setin (*set, elem)) {
    qh_setappend (set, elem);
    return 1;
  }
  return 0;
} /* setunique */
    
/*-<a                             href="qh-c.htm#set"
  >-------------------------------<a name="setzero">-</a>
  
  qh_setzero( set, index, size )
    zero elements from index on
    set actual size of set to size

  notes:
    set must be defined
    the set becomes an indexed set (can not use FOREACH...)
  
  see also:
    qh_settruncate
    
  design:
    check index and size
    update actual size
    zero elements starting at e[index]   
*/
void qh_setzero (setT *set, int index, int size) {
  int count;

  if (index < 0 || index >= size || size > set->maxsize) {
    fprintf (qhmem.ferr, "qhull internal error (qh_setzero): index %d or size %d out of bounds for set:\n", index, size);
    qh_setprint (qhmem.ferr, "", set);
    qh_errexit (qhmem_ERRqhull, NULL, NULL);
  }
  set->e[set->maxsize].i=  size+1;  /* may be overwritten */
  count= size - index + 1;   /* +1 for NULL terminator */
  memset ((char *)SETelemaddr_(set, index, void), 0, count * SETelemsize);
} /* setzero */