netcdf-c/include/nchttp.h
Dennis Heimbigner 3ffe7be446 Enhance/Fix filter support
re: Discussion https://github.com/Unidata/netcdf-c/discussions/2214

The primary change is to support so-called "standard filters".
A standard filter is one that is defined by the following
netcdf-c API:
````
int nc_def_var_XXX(int ncid, int varid, size_t nparams, unsigned* params);
int nc_inq_var_XXXX(int ncid, int varid, int* usefilterp, unsigned* params);
````
So for example, zstandard would be a standard filter by defining
the functions *nc_def_var_zstandard* and *nc_inq_var_zstandard*.

In order to define these functions, we need a new dispatch function:
````
int nc_inq_filter_avail(int ncid, unsigned filterid);
````
This function, combined with the existing filter API can be used
to implement arbitrary standard filters using a simple code pattern.
Note that I would have preferred that this function return a list
of all available filters, but HDF5 does not support that functionality.

So this PR implements the dispatch function and implements
the following standard functions:
    + bzip2
    + zstandard
    + blosc
Specific test cases are also provided for HDF5 and NCZarr.
Over time, other specific standard filters will be defined.

## Primary Changes
* Add nc_inq_filter_avail() to netcdf-c API.
* Add standard filter implementations to test use of *nc_inq_filter_avail*.
* Bump the dispatch table version number and add to all the relevant
   dispatch tables (libsrc, libsrcp, etc).
* Create a program to invoke nc_inq_filter_avail so that it is accessible
  to shell scripts.
* Cleanup szip support to properly support szip
  when HDF5 is disabled. This involves detecting
  libsz separately from testing if HDF5 supports szip.
* Integrate shuffle and fletcher32 into the existing
  filter API. This means that, for example, nc_def_var_fletcher32
  is now a wrapper around nc_def_var_filter.
* Extend the Codec defaulting to allow multiple default shared libraries.

## Misc. Changes
* Modify configure.ac/CMakeLists.txt to look for the relevant
  libraries implementing standard filters.
* Modify libnetcdf.settings to list available standard filters
  (including deflate and szip).
* Add CMake test modules to locate libbz2 and libzstd.
* Cleanup the HDF5 memory manager function use in the plugins.
* remove unused file include//ncfilter.h
* remove tests for the HDF5 memory operations e.g. H5allocate_memory.
* Add flag to ncdump to force use of _Filter instead of _Deflate
  or _Shuffle or _Fletcher32. Used for testing.
2022-03-14 12:39:37 -06:00

50 lines
1.9 KiB
C

/* Copyright 2018-2018 University Corporation for Atmospheric
Research/Unidata. */
/**
* Header file for dhttp.c
* @author Dennis Heimbigner
*/
#ifndef NCHTTP_H
#define NCHTTP_H
typedef enum HTTPMETHOD {
HTTPNONE=0, HTTPGET=1, HTTPPUT=2, HTTPPOST=3, HTTPHEAD=4, HTTPDELETE=5
} HTTPMETHOD;
struct CURL; /* Forward */
typedef struct NC_HTTP_STATE {
struct CURL* curl;
long httpcode;
struct Response {
NClist* headset; /* which headers to capture */
NClist* headers; /* Set of captured headers */
NCbytes* buf; /* response content; call owns; do not free */
} response;
struct Request {
HTTPMETHOD method;
size_t payloadsize;
void* payload; /* caller owns; do not free */
size_t payloadpos;
NClist* headers;
} request;
char errbuf[1024]; /* assert(CURL_ERROR_SIZE <= 1024) */
} NC_HTTP_STATE;
extern int nc_http_init(NC_HTTP_STATE** state);
extern int nc_http_init_verbose(NC_HTTP_STATE** state, int verbose);
extern int nc_http_size(NC_HTTP_STATE* state, const char* url, long long* sizep);
extern int nc_http_read(NC_HTTP_STATE* state, const char* url, size64_t start, size64_t count, NCbytes* buf);
extern int nc_http_write(NC_HTTP_STATE* state, const char* url, NCbytes* payload);
extern int nc_http_close(NC_HTTP_STATE* state);
extern int nc_http_reset(NC_HTTP_STATE* state);
extern int nc_http_set_method(NC_HTTP_STATE* state, HTTPMETHOD method);
extern int nc_http_set_response(NC_HTTP_STATE* state, NCbytes* buf);
extern int nc_http_set_payload(NC_HTTP_STATE* state, size_t len, void* payload);
extern int nc_http_response_headset(NC_HTTP_STATE* state, const NClist* headers); /* Set of headers to capture */
extern int nc_http_response_headers(NC_HTTP_STATE* state, NClist** headersp); /* set of captured headers */
extern int nc_http_request_setheaders(NC_HTTP_STATE* state, const NClist* headers); /* set of extra request headers */
#endif /*NCHTTP_H*/