netcdf-c/include/nc.h
Dennis Heimbigner f1506d552e Change (again), and hopefully simplify, the file model inference algorithm.
* For URL paths, the new approach essentially centralizes all information
  in the URL into the "#mode=" fragment key and uses that value
  to determine the dispatcher for (most) URLs.

* The new approach has the following steps:

  1. canonicalize the path if it is a URL.
  2. use the mode= fragment key to determine the dispatcher
  3. if dispatcher still not determined, then use the mode flags
     argument to nc_open/nc_create to determine the dispatcher.
  4. if the path points to something readable, attempt to read the
     magic number at the front, and use that to determine the dispatcher.
     this case may override all previous cases.

* Misc changes.

  1. Update documentation
  2. Moved some unit tests from libdispatch to unit_test directory.
  3. Fixed use of wrong #ifdef macro in test_filter_reg.c
     [I think this may fix an previously reported esupport query].
2019-09-29 12:59:28 -06:00

81 lines
2.4 KiB
C

/*
* Copyright 2018, University Corporation for Atmospheric Research
* See netcdf/COPYRIGHT file for copying and redistribution conditions.
*/
#ifndef _NC_H_
#define _NC_H_
#include "config.h"
#include "netcdf.h"
/* There's an external ncid (ext_ncid) and an internal ncid
* (int_ncid). The ext_ncid is the ncid returned to the user. If
* the user has opened or created a netcdf-4 file, then the
* ext_ncid is the same as the int_ncid. If he has opened or
* created a netcdf-3 file ext_ncid (which the user sees) is
* different from the int_ncid, which is the ncid returned by the
* netcdf-3 layer, which insists on inventing its own ncids,
* regardless of what is already in use due to previously opened
* netcdf-4 files. The ext_ncid contains the ncid for the root
* group (i.e. group zero). */
/* Common Shared Structure for all Dispatched Objects */
typedef struct NC {
int ext_ncid;
int int_ncid;
const struct NC_Dispatch* dispatch;
void* dispatchdata; /*per-'file' data; points to e.g. NC3_INFO data*/
char* path;
int mode; /* as provided to nc_open/nc_create */
} NC;
/*
* Counted string for names and such
*/
typedef struct {
/* all xdr'd */
size_t nchars;
char *cp;
} NC_string;
/* Define functions that are used across multiple dispatchers */
/* Begin defined in string.c */
extern void
free_NC_string(NC_string *ncstrp);
extern int
NC_check_name(const char *name);
extern NC_string *
new_NC_string(size_t slen, const char *str);
extern int
set_NC_string(NC_string *ncstrp, const char *str);
/* End defined in string.c */
extern int
NC_check_id(int ncid, NC **ncpp);
/* Create a pseudo file descriptor that does not
overlap real file descriptors */
extern int nc__pseudofd(void);
/* This function gets a current default create flag */
extern int nc_get_default_format(void);
extern int add_to_NCList(NC*);
extern void del_from_NCList(NC*);/* does not free object */
extern NC* find_in_NCList(int ext_ncid);
extern NC* find_in_NCList_by_name(const char*);
extern int move_in_NCList(NC *ncp, int new_id);
extern void free_NCList(void);/* reclaim whole list */
extern int count_NCList(void); /* return # of entries in NClist */
extern int iterate_NCList(int i,NC**); /* Walk from 0 ...; ERANGE return => stop */
/* Defined in nc.c */
extern void free_NC(NC*);
extern int new_NC(const struct NC_Dispatch*, const char*, int, NC**);
#endif /* _NC_H_ */