plyfile.cpp

在MATLAB环境下的level set方法的实现

}


/******************************************************************************
Specify a property of an element that is to be returned.  This should be
called (usually multiple times) before a call to the routine ply_get_element().
This routine should be used in preference to the less flexible old routine
called ply_get_element_setup().

Entry:
  plyfile   - file identifier
  elem_name - which element we're talking about
  prop      - property to add to those that will be returned
******************************************************************************/

void ply_get_property(
  PlyFile *plyfile,
  char *elem_name,
  PlyProperty *prop
)
{
  PlyElement *elem;
  PlyProperty *prop_ptr;
  int index;

  /* find information about the element */
  elem = find_element (plyfile, elem_name);
  plyfile->which_elem = elem;

  /* deposit the property information into the element's description */

  prop_ptr = find_property (elem, prop->name, &index);
  if (prop_ptr == NULL) {
    fprintf (stderr, "Warning:  Can't find property '%s' in element '%s'\n",
             prop->name, elem_name);
    return;
  }
  prop_ptr->internal_type  = prop->internal_type;
  prop_ptr->offset         = prop->offset;
  prop_ptr->count_internal = prop->count_internal;
  prop_ptr->count_offset   = prop->count_offset;

  /* specify that the user wants this property */
  elem->store_prop[index] = STORE_PROP;
}


/******************************************************************************
Read one element from the file.  This routine assumes that we're reading
the type of element specified in the last call to the routine
ply_get_element_setup().

Entry:
  plyfile  - file identifier
  elem_ptr - pointer to location where the element information should be put
******************************************************************************/

ply_get_element(PlyFile *plyfile, void *elem_ptr)
{
  if (plyfile->file_type == PLY_ASCII)
    ascii_get_element (plyfile, (char *) elem_ptr);
  else
    binary_get_element (plyfile, (char *) elem_ptr);
}


/******************************************************************************
Extract the comments from the header information of a PLY file.

Entry:
  plyfile - file identifier

Exit:
  num_comments - number of comments returned
  returns a pointer to a list of comments
******************************************************************************/

char **ply_get_comments(PlyFile *plyfile, int *num_comments)
{
  *num_comments = plyfile->num_comments;
  return (plyfile->comments);
}


/******************************************************************************
Extract the object information (arbitrary text) from the header information
of a PLY file.

Entry:
  plyfile - file identifier

Exit:
  num_obj_info - number of lines of text information returned
  returns a pointer to a list of object info lines
******************************************************************************/

char **ply_get_obj_info(PlyFile *plyfile, int *num_obj_info)
{
  *num_obj_info = plyfile->num_obj_info;
  return (plyfile->obj_info);
}


/******************************************************************************
Make ready for "other" properties of an element-- those properties that
the user has not explicitly asked for, but that are to be stashed away
in a special structure to be carried along with the element's other
information.

Entry:
  plyfile - file identifier
  elem    - element for which we want to save away other properties
******************************************************************************/

void setup_other_props(PlyFile *plyfile, PlyElement *elem)
{
  int i;
  PlyProperty *prop;
  int size = 0;
  int type_size;

  /* Examine each property in decreasing order of size. */
  /* We do this so that all data types will be aligned by */
  /* word, half-word, or whatever within the structure. */

  for (type_size = 8; type_size > 0; type_size /= 2) {

    /* add up the space taken by each property, and save this information */
    /* away in the property descriptor */

    for (i = 0; i < elem->nprops; i++) {

      /* don't bother with properties we've been asked to store explicitly */
      if (elem->store_prop[i])
        continue;

      prop = elem->props[i];

      /* internal types will be same as external */
      prop->internal_type = prop->external_type;
      prop->count_internal = prop->count_external;

      /* check list case */
      if (prop->is_list) {

        /* pointer to list */
        if (type_size == sizeof (void *)) {
          prop->offset = size;
          size += sizeof (void *);    /* always use size of a pointer here */
        }

        /* count of number of list elements */
        if (type_size == ply_type_size[prop->count_external]) {
          prop->count_offset = size;
          size += ply_type_size[prop->count_external];
        }
      }
      /* not list */
      else if (type_size == ply_type_size[prop->external_type]) {
        prop->offset = size;
        size += ply_type_size[prop->external_type];
      }
    }

  }

  /* save the size for the other_props structure */
  elem->other_size = size;
}


/******************************************************************************
Specify that we want the "other" properties of an element to be tucked
away within the user's structure.  The user needn't be concerned for how
these properties are stored.

Entry:
  plyfile   - file identifier
  elem_name - name of element that we want to store other_props in
  offset    - offset to where other_props will be stored inside user's structure

Exit:
  returns pointer to structure containing description of other_props
******************************************************************************/

PlyOtherProp *ply_get_other_properties(
  PlyFile *plyfile,
  char *elem_name,
  int offset
)
{
  int i;
  PlyElement *elem;
  PlyOtherProp *other;
  PlyProperty *prop;
  int nprops;

  /* find information about the element */
  elem = find_element (plyfile, elem_name);
  if (elem == NULL) {
    fprintf (stderr, "ply_get_other_properties: Can't find element '%s'\n",
             elem_name);
    return (NULL);
  }

  /* remember that this is the "current" element */
  plyfile->which_elem = elem;

  /* save the offset to where to store the other_props */
  elem->other_offset = offset;

  /* place the appropriate pointers, etc. in the element's property list */
  setup_other_props (plyfile, elem);

  /* create structure for describing other_props */
  other = (PlyOtherProp *) myalloc (sizeof (PlyOtherProp));
  other->name = strdup (elem_name);
#if 0
  if (elem->other_offset == NO_OTHER_PROPS) {
    other->size = 0;
    other->props = NULL;
    other->nprops = 0;
    return (other);
  }
#endif
  other->size = elem->other_size;
  other->props = (PlyProperty **) myalloc (sizeof(PlyProperty) * elem->nprops);
  
  /* save descriptions of each "other" property */
  nprops = 0;
  for (i = 0; i < elem->nprops; i++) {
    if (elem->store_prop[i])
      continue;
    prop = (PlyProperty *) myalloc (sizeof (PlyProperty));
    copy_property (prop, elem->props[i]);
    other->props[nprops] = prop;
    nprops++;
  }
  other->nprops = nprops;

#if 1
  /* set other_offset pointer appropriately if there are NO other properties */
  if (other->nprops == 0) {
    elem->other_offset = NO_OTHER_PROPS;
  }
#endif
  
  /* return structure */
  return (other);
}




/*************************/
/*  Other Element Stuff  */
/*************************/




/******************************************************************************
Grab all the data for an element that a user does not want to explicitly
read in.

Entry:
  plyfile    - pointer to file
  elem_name  - name of element whose data is to be read in
  elem_count - number of instances of this element stored in the file

Exit:
  returns pointer to ALL the "other" element data for this PLY file
******************************************************************************/

PlyOtherElems *ply_get_other_element (
  PlyFile *plyfile,
  char *elem_name,
  int elem_count
)
{
  int i;
  PlyElement *elem;
  PlyOtherElems *other_elems;
  OtherElem *other;
  int num_elems;

  /* look for appropriate element */
  elem = find_element (plyfile, elem_name);
  if (elem == NULL) {
    fprintf (stderr,
             "ply_get_other_element: can't find element '%s'\n", elem_name);
    exit (-1);
  }

  /* create room for the new "other" element, initializing the */
  /* other data structure if necessary */

  if (plyfile->other_elems == NULL) {
    plyfile->other_elems = (PlyOtherElems *) myalloc (sizeof (PlyOtherElems));
    other_elems = plyfile->other_elems;
    other_elems->other_list = (OtherElem *) myalloc (sizeof (OtherElem));
    other = &(other_elems->other_list[0]);
    other_elems->num_elems = 1;
  }
  else {
    other_elems = plyfile->other_elems;
    other_elems->other_list = (OtherElem *) realloc (other_elems->other_list,
                              sizeof (OtherElem) * other_elems->num_elems + 1);
    other = &(other_elems->other_list[other_elems->num_elems]);
    other_elems->num_elems++;
  }

  /* count of element instances in file */
  other->elem_count = elem_count;

  /* save name of element */
  other->elem_name = strdup (elem_name);

  /* create a list to hold all the current elements */
  other->other_data = (OtherData **)
                  malloc (sizeof (OtherData *) * other->elem_count);

  /* set up for getting elements */
  other->other_props = ply_get_other_properties (plyfile, elem_name,
                         offsetof(OtherData,other_props));

  /* grab all these elements */
  for (i = 0; i < other->elem_count; i++) {
    /* grab and element from the file */
    other->other_data[i] = (OtherData *) malloc (sizeof (OtherData));
    ply_get_element (plyfile, (void *) other->other_data[i]);
  }

  /* return pointer to the other elements data */
  return (other_elems);
}


/******************************************************************************
Pass along a pointer to "other" elements that we want to save in a given
PLY file.  These other elements were presumably read from another PLY file.

Entry:
  plyfile     - file pointer in which to store this other element info
  other_elems - info about other elements that we want to store
******************************************************************************/

void ply_describe_other_elements (
  PlyFile *plyfile,
  PlyOtherElems *other_elems
)
{
  int i;
  OtherElem *other;

  /* ignore this call if there is no other element */
  if (other_elems == NULL)
    return;

  /* save pointer to this information */
  plyfile->other_elems = other_elems;

  /* describe the other properties of this element */

  for (i = 0; i < other_elems->num_elems; i++) {
    other = &(other_elems->other_list[i]);
    ply_element_count (plyfile, other->elem_name, other->elem_count);
    ply_describe_other_properties (plyfile, other->other_props,
                                   offsetof(OtherData,other_props));
  }
}


/******************************************************************************
Write out the "other" elements specified for this PLY file.

Entry:
  plyfile - pointer to PLY file to write out other elements for
******************************************************************************/

void ply_put_other_elements (PlyFile *plyfile)
{
  int i,j;
  OtherElem *other;

  /* make sure we have other elements to write */
  if (plyfile->other_elems == NULL)
    return;

  /* write out the data for each "other" element */

  for (i = 0; i < plyfile->other_elems->num_elems; i++) {

    other = &(plyfile->other_elems->other_list[i]);
    ply_put_element_setup (plyfile, other->elem_name);

    /* write out each instance of the current element */
    for (j = 0; j < other->elem_count; j++)
      ply_put_element (plyfile, (void *) other->other_data[j]);
  }
}


/******************************************************************************
Free up storage used by an "other" elements data structure.

Entry:
  other_elems - data structure to free up
******************************************************************************/

void ply_free_other_elements (PlyOtherElems *other_elems)
{

}



/*******************/
/*  Miscellaneous  */
/*******************/



/******************************************************************************
Close a PLY file.

Entry:
  plyfile - identifier of file to close
******************************************************************************/

void ply_close(PlyFile *plyfile)
{
  fclose (plyfile->fp);

  /* free up memory associated with the PLY file */
  free (plyfile);
}


/******************************************************************************
Get version number and file type of a PlyFile.

Entry:
  ply - pointer to PLY file

Exit:
  version - version of the file
  file_type - PLY_ASCII, PLY_BINARY_BE, or PLY_BINARY_LE
******************************************************************************/

void ply_get_info(PlyFile *ply, float *version, int *file_type)
{
  if (ply == NULL)
    return;

  *version = ply->version;
  *file_type = ply->file_type;
}


/******************************************************************************
Compare two strings.  Returns 1 if they are the same, 0 if not.
******************************************************************************/

int equal_strings(char *s1, char *s2)
{
  int i;