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25f062528b
The file docs/indexing.dox tries to provide design information for the refactoring. The primary change is to replace all walking of linked lists with the use of the NCindex data structure. Ncindex is a combination of a hash table (for name-based lookup) and a vector (for walking the elements in the index). Additionally, global vectors are added to NC_HDF5_FILE_INFO_T to support direct mapping of an e.g. dimid to the NC_DIM_INFO_T object. These global vectors exist for dimensions, types, and groups because they have globally unique id numbers. WARNING: 1. since libsrc4 and libsrchdf4 share code, there are also changes in libsrchdf4. 2. Any outstanding pull requests that change libsrc4 or libhdf4 are likely to cause conflicts with this code. 3. The original reason for doing this was for performance improvements, but as noted elsewhere, this may not be significant because the meta-data read performance apparently is being dominated by the hdf5 library because we do bulk meta-data reading rather than lazy reading.
89 lines
2.6 KiB
C
89 lines
2.6 KiB
C
/*
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* Copyright 1996, University Corporation for Atmospheric Research
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* See netcdf/COPYRIGHT file for copying and redistribution conditions.
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*/
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#ifndef _NC_H_
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#define _NC_H_
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#include "config.h"
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#include "netcdf.h"
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/* There's an external ncid (ext_ncid) and an internal ncid
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* (int_ncid). The ext_ncid is the ncid returned to the user. If
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* the user has opened or created a netcdf-4 file, then the
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* ext_ncid is the same as the int_ncid. If he has opened or
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* created a netcdf-3 file ext_ncid (which the user sees) is
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* different from the int_ncid, which is the ncid returned by the
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* netcdf-3 layer, which insists on inventing its own ncids,
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* regardless of what is already in use due to previously opened
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* netcdf-4 files. The ext_ncid contains the ncid for the root
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* group (i.e. group zero). */
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/* Common Shared Structure for all Dispatched Objects */
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typedef struct NC {
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int ext_ncid;
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int int_ncid;
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struct NC_Dispatch* dispatch;
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void* dispatchdata; /*per-'file' data; points to e.g. NC3_INFO data*/
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char* path;
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int mode; /* as provided to nc_open/nc_create */
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int model; /* as determined by libdispatch/dfile.c */
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#ifdef USE_REFCOUNT
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int refcount; /* To enable multiple name-based opens */
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#endif
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} NC;
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/*
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* Counted string for names and such
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*/
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typedef struct {
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/* all xdr'd */
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size_t nchars;
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char *cp;
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} NC_string;
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/* Define functions that are used across multiple dispatchers */
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/* Begin defined in string.c */
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extern void
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free_NC_string(NC_string *ncstrp);
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extern int
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NC_check_name(const char *name);
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extern NC_string *
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new_NC_string(size_t slen, const char *str);
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extern int
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set_NC_string(NC_string *ncstrp, const char *str);
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/* End defined in string.c */
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extern int
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NC_check_id(int ncid, NC **ncpp);
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/* Create a pseudo file descriptor that does not
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overlap real file descriptors */
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extern int nc__pseudofd(void);
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/* This function gets a current default create flag */
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extern int nc_get_default_format(void);
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extern int NC_check_file_type(const char *path, int flags, void *parameters, int* model, int* version);
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extern int add_to_NCList(NC*);
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extern void del_from_NCList(NC*);/* does not free object */
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extern NC* find_in_NCList(int ext_ncid);
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extern NC* find_in_NCList_by_name(const char*);
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extern void free_NCList(void);/* reclaim whole list */
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extern int count_NCList(void); /* return # of entries in NClist */
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extern int iterate_NCList(int i,NC**); /* Walk from 0 ...; ERANGE return => stop */
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/* Defined in nc.c */
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extern void free_NC(NC*);
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extern int new_NC(struct NC_Dispatch*, const char*, int, int, NC**);
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/* Defined in nc.c */
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extern int ncdebug;
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#endif /* _NC_H_ */
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