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netcdf-c/libdispatch/dinfermodel.c
edwardhartnett b9f57b2b5f now UDF mode flags take priority over NC_NETCDF4
2019-11-13 12:13:33 -07:00

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/**
* @file
*
* Infer as much as possible from the omode + path.
* Rewrite the path to a canonical form.
*
* Copyright 2018 University Corporation for Atmospheric
* Research/Unidata. See COPYRIGHT file for more info.
*/
#include "config.h"
#include <stdlib.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include "ncdispatch.h"
#include "ncwinpath.h"
#include "netcdf_mem.h"
#include "fbits.h"
#include "ncbytes.h"
#include "nclist.h"
#include "nclog.h"
#ifdef ENABLE_BYTERANGE
#include "nchttp.h"
#endif
#undef DEBUG
/* If Defined, then use only stdio for all magic number io;
otherwise use stdio or mpio as required.
*/
#undef USE_STDIO
/**
Sort info for open/read/close of
file when searching for magic numbers
*/
struct MagicFile {
const char* path;
struct NCURI* uri;
int omode;
NCmodel* model;
fileoffset_t filelen;
int use_parallel;
void* parameters; /* !NULL if inmemory && !diskless */
FILE* fp;
#ifdef USE_PARALLEL
MPI_File fh;
#endif
#ifdef ENABLE_BYTERANGE
void* curl; /* avoid need to include curl.h */
char* curlurl; /* url to use with CURLOPT_SET_URL */
#endif
};
/** @internal Magic number for HDF5 files. To be consistent with
* H5Fis_hdf5, use the complete HDF5 magic number */
static char HDF5_SIGNATURE[MAGIC_NUMBER_LEN] = "\211HDF\r\n\032\n";
#define modelcomplete(model) ((model)->impl != 0)
#ifdef DEBUG
static void dbgflush(void)
{
fflush(stdout);
fflush(stderr);
}
static void
fail(int err)
{
return;
}
static int
check(int err)
{
if(err != NC_NOERR)
fail(err);
return err;
}
#else
#define check(err) (err)
#endif
/*
Define a table of "mode=" string values
from which the implementation can be inferred.
Note that only cases that can currently
take URLs are included.
*/
static struct FORMATMODES {
const char* tag;
const int impl; /* NC_FORMATX_XXX value */
} formatmodes[] = {
{"dap2",NC_FORMATX_DAP2},
{"dap4",NC_FORMATX_DAP4},
{"netcdf-3",NC_FORMATX_NC3},
{"classic",NC_FORMATX_NC3},
{"netcdf-4",NC_FORMATX_NC4},
{"enhanced",NC_FORMATX_NC4},
{"udf0",NC_FORMATX_UDF0},
{"udf1",NC_FORMATX_UDF1},
{"zarr",NC_FORMATX_ZARR},
{NULL,0},
};
/* Define the legal singleton mode tags;
thse should also appear in the above mode table. */
static const char* modesingles[] = {
"dap2", "dap4", "bytes", "zarr", NULL
};
/* Map FORMATX to readability to get magic number */
static struct Readable {
int impl;
int readable;
} readable[] = {
{NC_FORMATX_NC3,1},
{NC_FORMATX_NC_HDF5,1},
{NC_FORMATX_NC_HDF4,1},
{NC_FORMATX_PNETCDF,1},
{NC_FORMATX_DAP2,0},
{NC_FORMATX_DAP4,0},
{NC_FORMATX_UDF0,0},
{NC_FORMATX_UDF1,0},
{NC_FORMATX_ZARR,0},
{0,0},
};
/* Define the known URL protocols and their interpretation */
static struct NCPROTOCOLLIST {
const char* protocol;
const char* substitute;
const char* mode;
} ncprotolist[] = {
{"http",NULL,NULL},
{"https",NULL,NULL},
{"file",NULL,NULL},
{"dods","http","dap2"},
{"dap4","http","dap4"},
{NULL,NULL,NULL} /* Terminate search */
};
/* Forward */
static int NC_omodeinfer(int useparallel, int omode, NCmodel*);
static int check_file_type(const char *path, int omode, int use_parallel, void *parameters, NCmodel* model, NCURI* uri);
static int parseurlmode(const char* modestr, NClist* list);
static int processuri(const char* path, NCURI** urip, char** newpathp, NClist* modeargs);
static char* list2string(NClist* modelist);
static char* envv2string(NClist* envv);
static int issingleton(const char* tag);;
static void set_default_mode(int* cmodep);
static int openmagic(struct MagicFile* file);
static int readmagic(struct MagicFile* file, long pos, char* magic);
static int closemagic(struct MagicFile* file);
static int NC_interpret_magic_number(char* magic, NCmodel* model);
#ifdef DEBUG
static void printmagic(const char* tag, char* magic,struct MagicFile*);
#endif
static int isreadable(NCmodel*);
/*
If the path looks like a URL, then parse it, reformat it,
and compute the mode= flags. Then return it and the the reformatted path.
*/
static int
processuri(const char* path, NCURI** urip, char** newpathp, NClist* modeargs)
{
int i,j,stat = NC_NOERR;
int found = 0;
const char** fragp = NULL;
NClist* fraglist = NULL;
struct NCPROTOCOLLIST* protolist;
NCURI* uri = NULL;
size_t pathlen = strlen(path);
char* str = NULL;
if(path == NULL || pathlen == 0) {stat = NC_EURL; goto done;}
/* Defaults */
if(newpathp) *newpathp = NULL;
if(urip) *urip = NULL;
if(ncuriparse(path,&uri)) goto done; /* not url */
/* Look up the protocol */
for(found=0,protolist=ncprotolist;protolist->protocol;protolist++) {
if(strcmp(uri->protocol,protolist->protocol) == 0) {
found = 1;
break;
}
}
if(!found)
{stat = NC_EINVAL; goto done;} /* unrecognized URL form */
/* process the corresponding mode arg */
if(protolist->mode != NULL)
nclistpush(modeargs,strdup(protolist->mode));
/* Substitute the protocol in any case */
if(protolist->substitute) ncurisetprotocol(uri,protolist->substitute);
/* Iterate over the url fragment parameters and collect,
but remove mode= proto= and protocol= */
fraglist = nclistnew();
for(fragp=ncurifragmentparams(uri);fragp && *fragp;fragp+=2) {
int elide = 0;
const char* name = fragp[0];
const char* value = fragp[1];
if(strcmp(name,"protocol")==0
|| strcmp(name,"proto")==0) { /* for back compatibility */
nclistpush(modeargs,strdup(value));
elide = 1;
} else if(strcmp(name,"mode")==0) {
/* Capture the list of mode arguments */
if((stat = parseurlmode(value,modeargs))) goto done;
elide = 1;
} else if(issingleton(name) && (value == NULL || strlen(value)==0)) {
nclistpush(modeargs,strdup(name));
elide = 1;
} /*else ignore*/
if(!elide) {
/* Copy over */
nclistpush(fraglist,strdup(name));
if(value == NULL) value = "";
nclistpush(fraglist,strdup(value));
}
}
/* At this point modeargs should contain all mode-like args from the URL */
/* Remove duplicates */
for(i=nclistlength(modeargs)-1;i>=0;i--) {
const char* mode = nclistget(modeargs,i);
for(j=0;j<i;j++) {
const char* other = nclistget(modeargs,i);
if(strcasecmp(mode,other)==0) {
nclistremove(modeargs,i); /* duplicate */
break;
}
}
}
/* Convert the modelist to a new mode= fragment */
if(nclistlength(modeargs) > 0) {
str = list2string(modeargs);
/* Re-insert mode into fraglist */
nclistinsert(fraglist,0,str);
nclistinsert(fraglist,0,strdup("mode"));
}
/* Convert frag list to a string */
str = envv2string(fraglist);
ncurisetfragments(uri,str);
/* Rebuild the path (including fragment)*/
if(newpathp)
*newpathp = ncuribuild(uri,NULL,NULL,NCURIALL);
if(urip) {
*urip = uri;
uri = NULL;
}
#ifdef DEBUG
fprintf(stderr,"newpath=|%s|\n",*newpathp); fflush(stderr);
#endif
done:
nclistfreeall(fraglist);
nullfree(str);
if(uri != NULL) ncurifree(uri);
return check(stat);
}
/* Parse a mode string at the commas */
static int
parseurlmode(const char* modestr, NClist* list)
{
int stat = NC_NOERR;
const char* p = NULL;
const char* endp = NULL;
if(modestr == NULL || *modestr == '\0') goto done;
/* Split modestr at the commas or EOL */
p = modestr;
for(;;) {
char* s;
ptrdiff_t slen;
endp = strchr(p,',');
if(endp == NULL) endp = p + strlen(p);
slen = (endp - p);
if((s = malloc(slen+1)) == NULL) {stat = NC_ENOMEM; goto done;}
memcpy(s,p,slen);
s[slen] = '\0';
nclistpush(list,s);
if(*endp == '\0') break;
p = endp+1;
}
done:
return check(stat);
}
/* Convert an envv into a comma'd string*/
static char*
envv2string(NClist* envv)
{
int i;
NCbytes* buf = NULL;
char* result = NULL;
if(envv == NULL || nclistlength(envv) == 0) return NULL;
buf = ncbytesnew();
for(i=0;i<nclistlength(envv);i+=2) {
const char* key = nclistget(envv,i);
const char* val = nclistget(envv,i+1);
if(key == NULL || strlen(key) == 0) continue;
if(val == NULL) val = "";
if(i > 0) ncbytescat(buf,"&");
ncbytescat(buf,key);
ncbytescat(buf,"=");
ncbytescat(buf,val);
}
result = ncbytesextract(buf);
ncbytesfree(buf);
return result;
}
/* Convert a list into a comma'd string */
static char*
list2string(NClist* modelist)
{
int i;
NCbytes* buf = NULL;
char* result = NULL;
if(modelist == NULL || nclistlength(modelist)==0) return NULL;
buf = ncbytesnew();
for(i=0;i<nclistlength(modelist);i++) {
const char* m = nclistget(modelist,i);
if(m == NULL || strlen(m) == 0) continue;
if(i > 0) ncbytescat(buf,",");
ncbytescat(buf,m);
}
result = ncbytesextract(buf);
ncbytesfree(buf);
return result;
}
/* Given a mode= argument, fill in the impl and possibly mode flags */
static int
processmodearg(const char* arg, NCmodel* model)
{
int stat = NC_NOERR;
struct FORMATMODES* format = formatmodes;
for(;format->tag;format++) {
if(strcmp(format->tag,arg)==0) {
model->impl = format->impl;
}
}
return check(stat);
}
/* Search singleton list */
static int
issingleton(const char* tag)
{
const char** p;
for(p=modesingles;*p;p++) {
if(strcmp(*p,tag)==0) return 1;
}
return 0;
}
/*
Infer from the mode + useparallel
only call if iscreate or file is not easily readable.
*/
static int
NC_omodeinfer(int useparallel, int cmode, NCmodel* model)
{
int stat = NC_NOERR;
/* If no format flags are set, then use default */
if(!fIsSet(cmode,NC_FORMAT_ALL))
set_default_mode(&cmode);
/* Process the cmode; may override some already set flags. The
* user-defined formats must be checked first. They may choose to
* use some of the other flags, like NC_NETCDF4, so we must fist
* check NC_UDF0 and NC_UDF1 before checking for any other
* flag. */
if(fIsSet(cmode,(NC_UDF0|NC_UDF1))) {
model->format = NC_FORMAT_NETCDF4;
if(fIsSet(cmode,NC_UDF0)) {
model->impl = NC_FORMATX_UDF0;
} else {
model->impl = NC_FORMATX_UDF1;
}
goto done;
}
if(fIsSet(cmode,NC_64BIT_OFFSET)) {
model->impl = NC_FORMATX_NC3;
model->format = NC_FORMAT_64BIT_OFFSET;
goto done;
}
if(fIsSet(cmode,NC_64BIT_DATA)) {
model->impl = NC_FORMATX_NC3;
model->format = NC_FORMAT_64BIT_DATA;
goto done;
}
if(fIsSet(cmode,NC_NETCDF4)) {
model->impl = NC_FORMATX_NC4;
if(fIsSet(cmode,NC_CLASSIC_MODEL))
model->format = NC_FORMAT_NETCDF4_CLASSIC;
else
model->format = NC_FORMAT_NETCDF4;
goto done;
}
/* Default to classic model */
model->format = NC_FORMAT_CLASSIC;
model->impl = NC_FORMATX_NC3;
done:
/* Apply parallel flag */
if(useparallel) {
if(model->impl == NC_FORMATX_NC3)
model->impl = NC_FORMATX_PNETCDF;
}
return check(stat);
}
/*
If the mode flags do not necessarily specify the
format, then default it by adding in appropriate flags.
*/
static void
set_default_mode(int* modep)
{
int mode = *modep;
int dfaltformat;
dfaltformat = nc_get_default_format();
switch (dfaltformat) {
case NC_FORMAT_64BIT_OFFSET: mode |= NC_64BIT_OFFSET; break;
case NC_FORMAT_64BIT_DATA: mode |= NC_64BIT_DATA; break;
case NC_FORMAT_NETCDF4: mode |= NC_NETCDF4; break;
case NC_FORMAT_NETCDF4_CLASSIC: mode |= (NC_NETCDF4|NC_CLASSIC_MODEL); break;
case NC_FORMAT_CLASSIC: /* fall thru */
default: break; /* default to classic */
}
*modep = mode; /* final result */
}
/**************************************************/
/*
Infer model for this dataset using some
combination of cmode, path, and reading the dataset.
See the documentation in docs/internal.dox.
@param path
@param omode
@param iscreate
@param useparallel
@param params
@param model
@param newpathp
*/
int
NC_infermodel(const char* path, int* omodep, int iscreate, int useparallel, void* params, NCmodel* model, char** newpathp)
{
int i,stat = NC_NOERR;
char* newpath = NULL;
NCURI* uri = NULL;
int omode = *omodep;
NClist* modeargs = nclistnew();
/* Phase 1: Reformat the uri to canonical form; store canonical form
into newpath. Return the "mode=" list in modeargs */
if((stat = processuri(path, &uri, &newpath, modeargs))) goto done;
if(newpath == NULL) newpath = strdup(path); /* No change */
/* Phase 2: Process the modeargs list to see if we can tell the formatx */
/* Note that if the path was not a URL, then modeargs will be empty list*/
for(i=0;i<nclistlength(modeargs);i++) {
const char* arg = nclistget(modeargs,i);
if((stat=processmodearg(arg,model))) goto done;
}
/* Phase 2.5: Special case: if this is a URL, and there are no mode args
and model.impl is still not defined, default to DAP2 */
if(uri != NULL && nclistlength(modeargs) == 0 && !modelcomplete(model)) {
model->impl = NC_FORMATX_DAP2;
model->format = NC_FORMAT_NC3;
}
/* Phase 3: mode inference from mode flags */
/* The modeargs did not give us a model (probably not a URL).
So look at the combination of mode flags and the useparallel flag */
if(!modelcomplete(model)) {
if((stat = NC_omodeinfer(useparallel,omode,model))) goto done;
}
/* Phase 4: Infer from file content, if possible;
this has highest precedence, so it may override
previous decisions. Note that we do this last
because we need previously determined model info
to guess if this file is readable.
*/
if(!iscreate && isreadable(model)) {
/* Ok, we need to try to read the file */
if((stat = check_file_type(path, omode, useparallel, params, model, uri))) goto done;
}
/* Need a decision */
if(!modelcomplete(model))
{stat = NC_ENOTNC; goto done;}
/* Force flag consistency */
switch (model->impl) {
case NC_FORMATX_NC4:
case NC_FORMATX_NC_HDF4:
case NC_FORMATX_DAP4:
case NC_FORMATX_UDF0:
case NC_FORMATX_UDF1:
omode |= NC_NETCDF4;
if(model->format == NC_FORMAT_NETCDF4_CLASSIC)
omode |= NC_CLASSIC_MODEL;
break;
case NC_FORMATX_NC3:
omode &= ~NC_NETCDF4; /* must be netcdf-3 (CDF-1, CDF-2, CDF-5) */
if(model->format == NC_FORMAT_64BIT_OFFSET) omode |= NC_64BIT_OFFSET;
else if(model->format == NC_FORMAT_64BIT_DATA) omode |= NC_64BIT_DATA;
break;
case NC_FORMATX_PNETCDF:
omode &= ~NC_NETCDF4; /* must be netcdf-3 (CDF-1, CDF-2, CDF-5) */
if(model->format == NC_FORMAT_64BIT_OFFSET) omode |= NC_64BIT_OFFSET;
else if(model->format == NC_FORMAT_64BIT_DATA) omode |= NC_64BIT_DATA;
break;
case NC_FORMATX_DAP2:
omode &= ~(NC_NETCDF4|NC_64BIT_OFFSET|NC_64BIT_DATA|NC_CLASSIC_MODEL);
break;
default:
{stat = NC_ENOTNC; goto done;}
}
done:
if(uri) ncurifree(uri);
nclistfreeall(modeargs);
if(stat == NC_NOERR && newpathp) {*newpathp = newpath; newpath = NULL;}
nullfree(newpath);
*omodep = omode; /* in/out */
return check(stat);
}
static int
isreadable(NCmodel* model)
{
struct Readable* r;
/* Look up the protocol */
for(r=readable;r->impl;r++) {
if(model->impl == r->impl) return r->readable;
}
return 0;
}
/**************************************************/
#if 0
/* return 1 if path looks like a url; 0 otherwise */
int
NC_testurl(const char* path)
{
int isurl = 0;
NCURI* tmpurl = NULL;
if(path == NULL) return 0;
/* Ok, try to parse as a url */
if(ncuriparse(path,&tmpurl)==NCU_OK) {
/* Do some extra testing to make sure this really is a url */
/* Look for a known/accepted protocol */
struct NCPROTOCOLLIST* protolist;
for(protolist=ncprotolist;protolist->protocol;protolist++) {
if(strcmp(tmpurl->protocol,protolist->protocol) == 0) {
isurl=1;
break;
}
}
ncurifree(tmpurl);
return isurl;
}
return 0;
}
#endif
/**************************************************/
/**
* Provide a hidden interface to allow utilities
* to check if a given path name is really a url.
* If not, put null in basenamep, else put basename of the url
* minus any extension into basenamep; caller frees.
* Return 1 if it looks like a url, 0 otherwise.
*/
int
nc__testurl(const char* path, char** basenamep)
{
NCURI* uri;
int ok = 0;
if(!ncuriparse(path,&uri)) {
char* slash = (uri->path == NULL ? NULL : strrchr(uri->path, '/'));
char* dot;
if(slash == NULL) slash = (char*)path; else slash++;
slash = nulldup(slash);
if(slash == NULL)
dot = NULL;
else
dot = strrchr(slash, '.');
if(dot != NULL && dot != slash) *dot = '\0';
if(basenamep)
*basenamep=slash;
else if(slash)
free(slash);
ncurifree(uri);
ok = 1;
}
return ok;
}
/**************************************************/
/**
* @internal Given an existing file, figure out its format and return
* that format value (NC_FORMATX_XXX) in model arg. Assume any path
* conversion was already performed at a higher level.
*
* @param path File name.
* @param flags
* @param use_parallel
* @param parameters
* @param model Pointer that gets the model to use for the dispatch table.
* @param version Pointer that gets version of the file.
*
* @return ::NC_NOERR No error.
* @author Dennis Heimbigner
*/
static int
check_file_type(const char *path, int omode, int use_parallel,
void *parameters, NCmodel* model, NCURI* uri)
{
char magic[NC_MAX_MAGIC_NUMBER_LEN];
int status = NC_NOERR;
struct MagicFile magicinfo;
memset((void*)&magicinfo,0,sizeof(magicinfo));
magicinfo.path = path; /* do not free */
magicinfo.uri = uri; /* do not free */
magicinfo.omode = omode;
magicinfo.model = model; /* do not free */
magicinfo.parameters = parameters; /* do not free */
#ifdef USE_STDIO
magicinfo.use_parallel = 0;
#else
magicinfo.use_parallel = use_parallel;
#endif
if((status = openmagic(&magicinfo))) goto done;
/* Verify we have a large enough file */
if(magicinfo.filelen < MAGIC_NUMBER_LEN)
{status = NC_ENOTNC; goto done;}
if((status = readmagic(&magicinfo,0L,magic)) != NC_NOERR) {
status = NC_ENOTNC;
goto done;
}
/* Look at the magic number */
if(NC_interpret_magic_number(magic,model) == NC_NOERR
&& model->format != 0) {
if (model->format == NC_FORMAT_NC3 && use_parallel)
/* this is called from nc_open_par() and file is classic */
model->impl = NC_FORMATX_PNETCDF;
goto done; /* found something */
}
/* Remaining case when implementation is an HDF5 file;
search forward at starting at 512
and doubling to see if we have HDF5 magic number */
{
long pos = 512L;
for(;;) {
if((pos+MAGIC_NUMBER_LEN) > magicinfo.filelen)
{status = NC_ENOTNC; goto done;}
if((status = readmagic(&magicinfo,pos,magic)) != NC_NOERR)
{status = NC_ENOTNC; goto done; }
NC_interpret_magic_number(magic,model);
if(model->impl == NC_FORMATX_NC4) break;
/* double and try again */
pos = 2*pos;
}
}
done:
closemagic(&magicinfo);
return check(status);
}
/**
\internal
\ingroup datasets
Provide open, read and close for use when searching for magic numbers
*/
static int
openmagic(struct MagicFile* file)
{
int status = NC_NOERR;
if(fIsSet(file->omode,NC_INMEMORY)) {
/* Get its length */
NC_memio* meminfo = (NC_memio*)file->parameters;
assert(meminfo != NULL);
file->filelen = (long long)meminfo->size;
#ifdef ENABLE_BYTERANGE
} else if(file->uri != NULL) {
/* Construct a URL minus any fragment */
file->curlurl = ncuribuild(file->uri,NULL,NULL,NCURISVC);
/* Open the curl handle */
if((status=nc_http_open(file->curlurl,&file->curl,&file->filelen))) goto done;
#endif
} else {
#ifdef USE_PARALLEL
if (file->use_parallel) {
int retval;
MPI_Offset size;
assert(file->parameters != NULL);
if((retval = MPI_File_open(((NC_MPI_INFO*)file->parameters)->comm,
(char*)file->path,MPI_MODE_RDONLY,
((NC_MPI_INFO*)file->parameters)->info,
&file->fh)) != MPI_SUCCESS) {
#ifdef MPI_ERR_NO_SUCH_FILE
int errorclass;
MPI_Error_class(retval, &errorclass);
if (errorclass == MPI_ERR_NO_SUCH_FILE)
#ifdef NC_ENOENT
status = NC_ENOENT;
#else
status = errno;
#endif
else
#endif
status = NC_EPARINIT;
goto done;
}
/* Get its length */
if((retval=MPI_File_get_size(file->fh, &size)) != MPI_SUCCESS)
{status = NC_EPARINIT; goto done;}
file->filelen = (long long)size;
} else
#endif /* USE_PARALLEL */
{
if(file->path == NULL || strlen(file->path)==0)
{status = NC_EINVAL; goto done;}
#ifdef _WIN32
file->fp = NCfopen(file->path, "rb");
#else
file->fp = NCfopen(file->path, "r");
#endif
if(file->fp == NULL)
{status = errno; goto done;}
/* Get its length */
{
int fd = fileno(file->fp);
#ifdef _WIN32
__int64 len64 = _filelengthi64(fd);
if(len64 < 0)
{status = errno; goto done;}
file->filelen = (long long)len64;
#else
off_t size;
size = lseek(fd, 0, SEEK_END);
if(size == -1)
{status = errno; goto done;}
file->filelen = (long long)size;
#endif
}
rewind(file->fp);
}
}
done:
return check(status);
}
static int
readmagic(struct MagicFile* file, long pos, char* magic)
{
int status = NC_NOERR;
memset(magic,0,MAGIC_NUMBER_LEN);
if(fIsSet(file->omode,NC_INMEMORY)) {
char* mempos;
NC_memio* meminfo = (NC_memio*)file->parameters;
if((pos + MAGIC_NUMBER_LEN) > meminfo->size)
{status = NC_EINMEMORY; goto done;}
mempos = ((char*)meminfo->memory) + pos;
memcpy((void*)magic,mempos,MAGIC_NUMBER_LEN);
#ifdef DEBUG
printmagic("XXX: readmagic",magic,file);
#endif
#ifdef ENABLE_BYTERANGE
} else if(file->uri != NULL) {
NCbytes* buf = ncbytesnew();
fileoffset_t start = (size_t)pos;
fileoffset_t count = MAGIC_NUMBER_LEN;
status = nc_http_read(file->curl,file->curlurl,start,count,buf);
if(status == NC_NOERR) {
if(ncbyteslength(buf) != count)
status = NC_EINVAL;
else
memcpy(magic,ncbytescontents(buf),count);
}
ncbytesfree(buf);
#endif
} else {
#ifdef USE_PARALLEL
if (file->use_parallel) {
MPI_Status mstatus;
int retval;
if((retval = MPI_File_read_at_all(file->fh, pos, magic,
MAGIC_NUMBER_LEN, MPI_CHAR, &mstatus)) != MPI_SUCCESS)
{status = NC_EPARINIT; goto done;}
} else
#endif /* USE_PARALLEL */
{
int count;
int i = fseek(file->fp,pos,SEEK_SET);
if(i < 0)
{status = errno; goto done;}
for(i=0;i<MAGIC_NUMBER_LEN;) {/* make sure to read proper # of bytes */
count=fread(&magic[i],1,(size_t)(MAGIC_NUMBER_LEN-i),file->fp);
if(count == 0 || ferror(file->fp))
{status = errno; goto done;}
i += count;
}
}
}
done:
if(file && file->fp) clearerr(file->fp);
return check(status);
}
/**
* Close the file opened to check for magic number.
*
* @param file pointer to the MagicFile struct for this open file.
* @returns NC_NOERR for success
* @returns NC_EPARINIT if there was a problem closing file with MPI
* (parallel builds only).
* @author Dennis Heimbigner
*/
static int
closemagic(struct MagicFile* file)
{
int status = NC_NOERR;
if(fIsSet(file->omode,NC_INMEMORY)) {
/* noop */
#ifdef ENABLE_BYTERANGE
} else if(file->uri != NULL) {
status = nc_http_close(file->curl);
nullfree(file->curlurl);
#endif
} else {
#ifdef USE_PARALLEL
if (file->use_parallel) {
int retval;
if((retval = MPI_File_close(&file->fh)) != MPI_SUCCESS)
{status = NC_EPARINIT; return status;}
} else
#endif
{
if(file->fp) fclose(file->fp);
}
}
return status;
}
/*!
Interpret the magic number found in the header of a netCDF file.
This function interprets the magic number/string contained in the header of a netCDF file and sets the appropriate NC_FORMATX flags.
@param[in] magic Pointer to a character array with the magic number block.
@param[out] model Pointer to an integer to hold the corresponding netCDF type.
@param[out] version Pointer to an integer to hold the corresponding netCDF version.
@returns NC_NOERR if a legitimate file type found
@returns NC_ENOTNC otherwise
\internal
\ingroup datasets
*/
static int
NC_interpret_magic_number(char* magic, NCmodel* model)
{
int status = NC_NOERR;
/* Look at the magic number */
#ifdef USE_NETCDF4
if (strlen(UDF0_magic_number) && !strncmp(UDF0_magic_number, magic,
strlen(UDF0_magic_number)))
{
model->impl = NC_FORMATX_UDF0;
model->format = NC_FORMAT_NETCDF4;
goto done;
}
if (strlen(UDF1_magic_number) && !strncmp(UDF1_magic_number, magic,
strlen(UDF1_magic_number)))
{
model->impl = NC_FORMATX_UDF1;
model->format = NC_FORMAT_NETCDF4;
goto done;
}
#endif /* USE_NETCDF4 */
/* Use the complete magic number string for HDF5 */
if(memcmp(magic,HDF5_SIGNATURE,sizeof(HDF5_SIGNATURE))==0) {
model->impl = NC_FORMATX_NC4;
model->format = NC_FORMAT_NETCDF4;
goto done;
}
if(magic[0] == '\016' && magic[1] == '\003'
&& magic[2] == '\023' && magic[3] == '\001') {
model->impl = NC_FORMATX_NC_HDF4;
model->format = NC_FORMAT_NETCDF4;
goto done;
}
if(magic[0] == 'C' && magic[1] == 'D' && magic[2] == 'F') {
if(magic[3] == '\001') {
model->impl = NC_FORMATX_NC3;
model->format = NC_FORMAT_CLASSIC;
goto done;
}
if(magic[3] == '\002') {
model->impl = NC_FORMATX_NC3;
model->format = NC_FORMAT_64BIT_OFFSET;
goto done;
}
if(magic[3] == '\005') {
model->impl = NC_FORMATX_NC3;
model->format = NC_FORMAT_64BIT_DATA;
goto done;
}
}
/* No match */
status = NC_ENOTNC;
goto done;
done:
return check(status);
}
#ifdef DEBUG
static void
printmagic(const char* tag, char* magic, struct MagicFile* f)
{
int i;
fprintf(stderr,"%s: ispar=%d magic=",tag,f->use_parallel);
for(i=0;i<MAGIC_NUMBER_LEN;i++) {
unsigned int c = (unsigned int)magic[i];
c = c & 0x000000FF;
if(c == '\n')
fprintf(stderr," 0x%0x/'\\n'",c);
else if(c == '\r')
fprintf(stderr," 0x%0x/'\\r'",c);
else if(c < ' ')
fprintf(stderr," 0x%0x/'?'",c);
else
fprintf(stderr," 0x%0x/'%c'",c,c);
}
fprintf(stderr,"\n");
fflush(stderr);
}
#endif
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