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https://github.com/Unidata/netcdf-c.git
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ccc70d640b
and https://github.com/Unidata/netcdf-c/issues/708 Expand the NC_INMEMORY capabilities to support writing and accessing the final modified memory. Three new functions have been added: nc_open_memio, nc_create_mem, and nc_close_memio. The following new capabilities were added. 1. nc_open_memio() allows the NC_WRITE mode flag so a chunk of memory can be passed in and be modified 2. nc_create_mem() allows the NC_INMEMORY flag to be set to cause the created file to be kept in memory. 3. nc_close_mem() allows the final in-memory contents to be retrieved at the time the file is closed. 4. A special flag, NC_MEMIO_LOCK, is provided to ensure that the provided memory will not be freed or reallocated. Note the following. 1. If nc_open_memio() is called with NC_WRITE, and NC_MEMIO_LOCK is not set, then the netcdf-c library will take control of the incoming memory. This means that the original memory block should not be freed but the block returned by nc_close_mem() must be freed. 2. If nc_open_memio() is called with NC_WRITE, and NC_MEMIO_LOCK is set, then modifications to the original memory may fail if the space available is insufficient. Documentation is provided in the file docs/inmemory.md. A test case is provided: nc_test/tst_inmemory.c driven by nc_test/run_inmemory.sh WARNING: changes were made to the dispatch table for the close entry. From int (*close)(int) to int (*close)(int,void*).
145 lines
4.3 KiB
C
145 lines
4.3 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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#if HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <stdlib.h>
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#include "netcdf.h"
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#include "ncio.h"
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#include "fbits.h"
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/* With the advent of diskless io, we need to provide
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for multiple ncio packages at the same time,
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so we have multiple versions of ncio_create.
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*/
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/* Define known ncio packages */
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extern int posixio_create(const char*,int,size_t,off_t,size_t,size_t*,void*,ncio**,void** const);
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extern int posixio_open(const char*,int,off_t,size_t,size_t*,void*,ncio**,void** const);
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extern int stdio_create(const char*,int,size_t,off_t,size_t,size_t*,void*,ncio**,void** const);
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extern int stdio_open(const char*,int,off_t,size_t,size_t*,void*,ncio**,void** const);
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#ifdef USE_FFIO
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extern int ffio_create(const char*,int,size_t,off_t,size_t,size_t*,void*,ncio**,void** const);
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extern int ffio_open(const char*,int,off_t,size_t,size_t*,void*,ncio**,void** const);
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#endif
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#ifdef USE_DISKLESS
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# ifdef USE_MMAP
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extern int mmapio_create(const char*,int,size_t,off_t,size_t,size_t*,void*,ncio**,void** const);
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extern int mmapio_open(const char*,int,off_t,size_t,size_t*,void*,ncio**,void** const);
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# endif
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extern int memio_create(const char*,int,size_t,off_t,size_t,size_t*,void*,ncio**,void** const);
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extern int memio_open(const char*,int,off_t,size_t,size_t*,void*,ncio**,void** const);
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#endif
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int
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ncio_create(const char *path, int ioflags, size_t initialsz,
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off_t igeto, size_t igetsz, size_t *sizehintp,
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void* parameters,
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ncio** iopp, void** const mempp)
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{
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#ifdef USE_DISKLESS
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if(fIsSet(ioflags,NC_INMEMORY)) {
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# ifdef USE_MMAP
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if(fIsSet(ioflags,NC_MMAP) && fIsSet(ioflags, NC_DISKLESS))
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return mmapio_create(path,ioflags,initialsz,igeto,igetsz,sizehintp,parameters,iopp,mempp);
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else
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# endif /*USE_MMAP*/
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return memio_create(path,ioflags,initialsz,igeto,igetsz,sizehintp,parameters,iopp,mempp);
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}
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#endif
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#ifdef USE_STDIO
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return stdio_create(path,ioflags,initialsz,igeto,igetsz,sizehintp,parameters,iopp,mempp);
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#elif defined(USE_FFIO)
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return ffio_create(path,ioflags,initialsz,igeto,igetsz,sizehintp,parameters,iopp,mempp);
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#else
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return posixio_create(path,ioflags,initialsz,igeto,igetsz,sizehintp,parameters,iopp,mempp);
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#endif
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}
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int
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ncio_open(const char *path, int ioflags,
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off_t igeto, size_t igetsz, size_t *sizehintp,
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void* parameters,
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ncio** iopp, void** const mempp)
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{
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/* Diskless open has the following constraints:
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1. file must be classic version 1 or 2 or 5
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*/
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#ifdef USE_DISKLESS
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if(fIsSet(ioflags,NC_INMEMORY)) {
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# ifdef USE_MMAP
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if(fIsSet(ioflags,NC_MMAP) && fIsSet(ioflags, NC_DISKLESS))
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return mmapio_open(path,ioflags,igeto,igetsz,sizehintp,parameters,iopp,mempp);
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else
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# endif /*USE_MMAP*/
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return memio_open(path,ioflags,igeto,igetsz,sizehintp,parameters,iopp,mempp);
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}
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#endif
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#ifdef USE_STDIO
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return stdio_open(path,ioflags,igeto,igetsz,sizehintp,parameters,iopp,mempp);
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#elif defined(USE_FFIO)
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return ffio_open(path,ioflags,igeto,igetsz,sizehintp,parameters,iopp,mempp);
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#else
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return posixio_open(path,ioflags,igeto,igetsz,sizehintp,parameters,iopp,mempp);
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#endif
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}
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/**************************************************/
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/* wrapper functions for the ncio dispatch table */
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int
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ncio_rel(ncio* const nciop, off_t offset, int rflags)
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{
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return nciop->rel(nciop,offset,rflags);
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}
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int
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ncio_get(ncio* const nciop, off_t offset, size_t extent,
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int rflags, void **const vpp)
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{
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return nciop->get(nciop,offset,extent,rflags,vpp);
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}
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int
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ncio_move(ncio* const nciop, off_t to, off_t from, size_t nbytes, int rflags)
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{
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return nciop->move(nciop,to,from,nbytes,rflags);
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}
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int
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ncio_sync(ncio* const nciop)
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{
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return nciop->sync(nciop);
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}
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int
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ncio_filesize(ncio* const nciop, off_t *filesizep)
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{
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return nciop->filesize(nciop,filesizep);
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}
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int
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ncio_pad_length(ncio* const nciop, off_t length)
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{
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return nciop->pad_length(nciop,length);
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}
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int
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ncio_close(ncio* const nciop, int doUnlink)
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{
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/* close and release all resources associated
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with nciop, including nciop
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*/
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int status = nciop->close(nciop,doUnlink);
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return status;
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}
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