/*************/
/*  Writing  */
/*************/


/******************************************************************************
Open a polygon file for writing.

Entry:
  filename   - name of file to read from
  nelems     - number of elements in object
  elem_names - list of element names
  file_type  - file type, either ascii or binary

Exit:
  version - version number of PLY file
  returns a file identifier, used to refer to this file, or NULL if error
******************************************************************************/

PlyFile *ply_open_for_writing(
  char *filename,
  int nelems,
  char **elem_names,
  int file_type,
  float *version
)

/******************************************************************************
Describe an element, including its properties and how many will be written
to the file.

Entry:
  plyfile   - file identifier
  elem_name - name of element that information is being specified about
  nelems    - number of elements of this type to be written
  nprops    - number of properties contained in the element
  prop_list - list of properties
******************************************************************************/

void ply_describe_element(
  PlyFile *plyfile,
  char *elem_name,
  int nelems,
  int nprops,
  PlyProperty *prop_list
)

/******************************************************************************
Signal that we've described everything a PLY file's header and that the
header should be written to the file.

Entry:
  plyfile - file identifier
******************************************************************************/

void ply_header_complete(PlyFile *plyfile)

/******************************************************************************
Specify which elements are going to be written.  This should be called
before a call to the routine ply_put_elements().

Entry:
  plyfile   - file identifier
  elem_name - name of element we're talking about
******************************************************************************/

void ply_put_elements_setup(PlyFile *plyfile, char *elem_name)

/******************************************************************************
Write an element to the file.  This routine assumes that we're
writing the type of element specified in the last call to the routine
ply_put_element_setup().

Entry:
  plyfile  - file identifier
  elem_ptr - pointer to the element
******************************************************************************/

void ply_put_element(PlyFile *plyfile, void *elem_ptr)

/******************************************************************************
Specify a comment that will be written in the header.

Entry:
  plyfile - file identifier
  comment - the comment to be written
******************************************************************************/

void ply_put_comment(PlyFile *plyfile, char *comment)

/******************************************************************************
Specify a piece of object information (arbitrary text) that will be written
in the header.

Entry:
  plyfile  - file identifier
  obj_info - the text information to be written
******************************************************************************/

void ply_put_obj_info(PlyFile *plyfile, char *obj_info)




/*************/
/*  Reading  */
/*************/



/******************************************************************************
Open a polygon file for reading.

Entry:
  filename - name of file to read from

Exit:
  nelems     - number of elements in object
  elem_names - list of element names
  file_type  - file type, either ascii or binary
  version    - version number of PLY file
  returns a file identifier, used to refer to this file, or NULL if error
******************************************************************************/

PlyFile *ply_open_for_reading(
  char *filename,
  int *nelems,
  char ***elem_names,
  int *file_type,
  float *version
)

/******************************************************************************
Get information about a particular element.

Entry:
  plyfile   - file identifier
  elem_name - name of element to get information about

Exit:
  nelems   - number of elements of this type in the file
  nprops   - number of properties
  returns a list of properties
******************************************************************************/

PlyProperty **ply_get_element_description(
  PlyFile *plyfile,
  char *elem_name,
  int *nelems,
  int *nprops
)

/******************************************************************************
Specify which properties of an element are to be returned.  This should be
called before a call to the routine ply_get_elements().

Entry:
  plyfile   - file identifier
  elem_name - which element we're talking about
  nprops    - number of properties
  prop_list - list of properties
******************************************************************************/

void ply_get_element_setup(
  PlyFile *plyfile,
  char *elem_name,
  int nprops,
  PlyProperty *prop_list
)

/******************************************************************************
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)

/******************************************************************************
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)

/******************************************************************************
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)



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



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

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

void ply_close(PlyFile *plyfile)

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

int equal_strings(char *s1, char *s2)