mirror of
https://github.com/Unidata/netcdf-c.git
synced 2024-11-27 07:30:33 +08:00
bf2746b8ea
re: issue https://github.com/Unidata/netcdf-c/issues/1251 Assume that you have the URL to a remote dataset which is a normal netcdf-3 or netcdf-4 file. This PR allows the netcdf-c to read that dataset's contents as a netcdf file using HTTP byte ranges if the remote server supports byte-range access. Originally, this PR was set up to access Amazon S3 objects, but it can also access other remote datasets such as those provided by a Thredds server via the HTTPServer access protocol. It may also work for other kinds of servers. Note that this is not intended as a true production capability because, as is known, this kind of access to can be quite slow. In addition, the byte-range IO drivers do not currently do any sort of optimization or caching. An additional goal here is to gain some experience with the Amazon S3 REST protocol. This architecture and its use documented in the file docs/byterange.dox. There are currently two test cases: 1. nc_test/tst_s3raw.c - this does a simple open, check format, close cycle for a remote netcdf-3 file and a remote netcdf-4 file. 2. nc_test/test_s3raw.sh - this uses ncdump to investigate some remote datasets. This PR also incorporates significantly changed model inference code (see the superceded PR https://github.com/Unidata/netcdf-c/pull/1259). 1. It centralizes the code that infers the dispatcher. 2. It adds support for byte-range URLs Other changes: 1. NC_HDF5_finalize was not being properly called by nc_finalize(). 2. Fix minor bug in ncgen3.l 3. fix memory leak in nc4info.c 4. add code to walk the .daprc triples and to replace protocol= fragment tag with a more general mode= tag. Final Note: Th inference code is still way too complicated. We need to move to the validfile() model used by netcdf Java, where each dispatcher is asked if it can process the file. This decentralizes the inference code. This will be done after all the major new dispatchers (PIO, Zarr, etc) have been implemented.
118 lines
2.8 KiB
C
118 lines
2.8 KiB
C
/*
|
|
* Copyright 2018, University Corporation for Atmospheric Research
|
|
* See netcdf/COPYRIGHT file for copying and redistribution conditions.
|
|
*/
|
|
|
|
#include "config.h"
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <assert.h>
|
|
#if defined(LOCKNUMREC) /* && _CRAYMPP */
|
|
# include <mpp/shmem.h>
|
|
# include <intrinsics.h>
|
|
#endif
|
|
#ifdef HAVE_UNISTD_H
|
|
#include <unistd.h>
|
|
#endif
|
|
|
|
#include "ncdispatch.h"
|
|
|
|
int ncdebug = 0;
|
|
|
|
/* This is the default create format for nc_create and nc__create. */
|
|
static int default_create_format = NC_FORMAT_CLASSIC;
|
|
|
|
/* These have to do with version numbers. */
|
|
#define MAGIC_NUM_LEN 4
|
|
#define VER_CLASSIC 1
|
|
#define VER_64BIT_OFFSET 2
|
|
#define VER_HDF5 3
|
|
|
|
int
|
|
NC_check_id(int ncid, NC** ncpp)
|
|
{
|
|
NC* nc = find_in_NCList(ncid);
|
|
if(nc == NULL) return NC_EBADID;
|
|
if(ncpp) *ncpp = nc;
|
|
return NC_NOERR;
|
|
}
|
|
|
|
void
|
|
free_NC(NC *ncp)
|
|
{
|
|
if(ncp == NULL)
|
|
return;
|
|
if(ncp->path)
|
|
free(ncp->path);
|
|
if(ncp->model)
|
|
free(ncp->model);
|
|
/* We assume caller has already cleaned up ncp->dispatchdata */
|
|
#if _CRAYMPP && defined(LOCKNUMREC)
|
|
shfree(ncp);
|
|
#else
|
|
free(ncp);
|
|
#endif /* _CRAYMPP && LOCKNUMREC */
|
|
}
|
|
|
|
int
|
|
new_NC(NC_Dispatch* dispatcher, const char* path, int mode, NCmodel* model, NC** ncpp)
|
|
{
|
|
NC *ncp = (NC*)calloc(1,sizeof(NC));
|
|
if(ncp == NULL) return NC_ENOMEM;
|
|
ncp->dispatch = dispatcher;
|
|
ncp->path = nulldup(path);
|
|
ncp->mode = mode;
|
|
if((ncp->model = malloc(sizeof(NCmodel)))==NULL)
|
|
return NC_ENOMEM;
|
|
*ncp->model = *model; /* Make a copy */
|
|
if(ncp->path == NULL) { /* fail */
|
|
free_NC(ncp);
|
|
return NC_ENOMEM;
|
|
}
|
|
if(ncpp) {
|
|
*ncpp = ncp;
|
|
} else {
|
|
free_NC(ncp);
|
|
}
|
|
return NC_NOERR;
|
|
}
|
|
|
|
/* This function sets a default create flag that will be logically
|
|
or'd to whatever flags are passed into nc_create for all future
|
|
calls to nc_create.
|
|
Valid default create flags are NC_64BIT_OFFSET, NC_CLOBBER,
|
|
NC_LOCK, NC_SHARE. */
|
|
int
|
|
nc_set_default_format(int format, int *old_formatp)
|
|
{
|
|
/* Return existing format if desired. */
|
|
if (old_formatp)
|
|
*old_formatp = default_create_format;
|
|
|
|
/* Make sure only valid format is set. */
|
|
#ifndef ENABLE_CDF5
|
|
if (format == NC_FORMAT_CDF5)
|
|
return NC_ENOTBUILT;
|
|
#endif
|
|
#ifdef USE_HDF5
|
|
if (format != NC_FORMAT_CLASSIC && format != NC_FORMAT_64BIT_OFFSET &&
|
|
format != NC_FORMAT_NETCDF4 && format != NC_FORMAT_NETCDF4_CLASSIC &&
|
|
format != NC_FORMAT_CDF5)
|
|
return NC_EINVAL;
|
|
#else
|
|
if (format == NC_FORMAT_NETCDF4 || format == NC_FORMAT_NETCDF4_CLASSIC)
|
|
return NC_ENOTBUILT;
|
|
if (format != NC_FORMAT_CLASSIC && format != NC_FORMAT_64BIT_OFFSET &&
|
|
format != NC_FORMAT_CDF5)
|
|
return NC_EINVAL;
|
|
#endif
|
|
default_create_format = format;
|
|
return NC_NOERR;
|
|
}
|
|
|
|
int
|
|
nc_get_default_format(void)
|
|
{
|
|
return default_create_format;
|
|
}
|