netcdf-c/libdap2/ncdap3.c

/*********************************************************************
 *   Copyright 1993, UCAR/Unidata
 *   See netcdf/COPYRIGHT file for copying and redistribution conditions.
 *   $Header: /upc/share/CVS/netcdf-3/libncdap3/ncdap3.c,v 1.94 2010/05/28 01:05:34 dmh Exp $
 *********************************************************************/

#include "ncdap3.h"

#ifdef HAVE_GETRLIMIT
#  ifdef HAVE_SYS_RESOURCE_H
#    include <sys/time.h>
#  endif
#  ifdef HAVE_SYS_RESOURCE_H
#    include <sys/resource.h>
#  endif
#endif

#include "oclog.h"

#include "nc3internal.h"
#include "nc3dispatch.h"
#include "ncd3dispatch.h"
#include "dapalign.h"
#include "dapdump.h"

static NCerror buildncstructures3(NCDAPCOMMON*);
static NCerror builddims(NCDAPCOMMON*);
static NCerror buildvars(NCDAPCOMMON*);
static NCerror buildglobalattrs3(NCDAPCOMMON*,CDFnode* root);
static NCerror buildattribute3a(NCDAPCOMMON*, NCattribute*, nc_type, int);


static char* getdefinename(CDFnode* node);

static int ncd3initialized = 0;

size_t dap_one[NC_MAX_VAR_DIMS];
size_t dap_zero[NC_MAX_VAR_DIMS];

/**************************************************/
/* Add an extra function whose sole purpose is to allow
   configure(.ac) to test for the presence of thiscode.
*/
int nc__opendap(void) {return 0;}

/**************************************************/
/* Do local initialization */

static int
ncd3initialize(void)
{
    int i;
    compute_nccalignments();
    for(i=0;i<NC_MAX_VAR_DIMS;i++) {
	dap_one[i] = 1;
	dap_zero[i] = 0;
    }
    ncd3initialized = 1;
#ifdef DEBUG
    /* force logging to go to stderr */
    nclogclose();
    if(nclogopen(NULL))
        ncsetlogging(1); /* turn it on */
#endif
    return NC_NOERR;
}

/**************************************************/

/* See ncd3dispatch.c for other version */
int
NCD3_open(const char * path, int mode,
               int basepe, size_t *chunksizehintp,
 	       int useparallel, void* mpidata,
               NC_Dispatch* dispatch, NC* drno)
{
    NCerror ncstat = NC_NOERR;
    OCerror ocstat = OC_NOERR;
    NCDAPCOMMON* dapcomm = NULL;
    const char* value;

    if(!ncd3initialized) ncd3initialize();

    if(path == NULL)
	return NC_EDAPURL;
    if(dispatch == NULL) PANIC("NC3D_open: no dispatch table");

    /* Setup our NC and NCDAPCOMMON state*/

    dapcomm = (NCDAPCOMMON*)calloc(1,sizeof(NCDAPCOMMON));
    if(dapcomm == NULL) {ncstat = NC_ENOMEM; goto done;}

    NCD3_DATA_SET(drno,dapcomm);
    drno->int_ncid = nc__pseudofd(); /* create a unique id */
    dapcomm->controller = (NC*)drno;

    dapcomm->cdf.separator = ".";
    dapcomm->cdf.smallsizelimit = DFALTSMALLLIMIT;
    dapcomm->cdf.cache = createnccache();

#ifdef HAVE_GETRLIMIT
    { struct rlimit rl;
      if(getrlimit(RLIMIT_NOFILE, &rl) >= 0) {
	dapcomm->cdf.cache->cachecount = (size_t)(rl.rlim_cur / 2);
      }
    }
#endif

#ifdef OCCOMPILEBYDEFAULT
    /* set the compile flag by default */
    dapcomm->oc.rawurltext = (char*)emalloc(strlen(path)+strlen("[compile]")+1);
    strcpy(dapcomm->oc.rawurltext,"[compile]");
    strcat(dapcomm->oc.rawurltext, path);    
#else
    dapcomm->oc.rawurltext = strdup(path);
#endif

    ncuriparse(dapcomm->oc.rawurltext,&dapcomm->oc.url);

    /* parse the client parameters */
    ncuridecodeparams(dapcomm->oc.url);

    if(!constrainable34(dapcomm->oc.url))
	SETFLAG(dapcomm->controls,NCF_UNCONSTRAINABLE);

    /* fail if we are unconstrainable but have constraints */
    if(FLAGSET(dapcomm->controls,NCF_UNCONSTRAINABLE)) {
	if(dapcomm->oc.url->constraint != NULL) {
	    nclog(NCLOGWARN,"Attempt to constrain an unconstrainable data source: %s",
		   dapcomm->oc.url->constraint);
	    ncstat = THROW(NC_EDAPCONSTRAINT);
	    goto done;
	}
    }

    /* Use libsrc code for storing metadata */
    {
	char tmpname[32];

        /* Create fake file name: exact name must be unique,
           but is otherwise irrelevant because we are using NC_DISKLESS
        */
        snprintf(tmpname,sizeof(tmpname),"%d",drno->int_ncid);

        /* Now, use the file to create the netcdf file; force classic.  */
        ncstat = nc_create(tmpname,NC_DISKLESS|NC_CLASSIC_MODEL,&drno->substrate);
        if(ncstat != NC_NOERR) {THROWCHK(ncstat); goto done;}
    }

    /* Avoid fill */
    nc_set_fill(drno->substrate,NC_NOFILL,NULL);

    dapcomm->oc.dapconstraint = (DCEconstraint*)dcecreate(CES_CONSTRAINT);
    dapcomm->oc.dapconstraint->projections = nclistnew();
    dapcomm->oc.dapconstraint->selections = nclistnew();
    
    if(dapcomm->oc.url != NULL) {
        /* Parse constraints to make sure they are syntactically correct */
        ncstat = parsedapconstraints(dapcomm,dapcomm->oc.url->constraint,dapcomm->oc.dapconstraint);
        if(ncstat != NC_NOERR) {THROWCHK(ncstat); goto done;}
     } else
	dapcomm->oc.dapconstraint = NULL;

    /* Construct a url for oc minus any constraint and params*/
    dapcomm->oc.urltext = ncuribuild(dapcomm->oc.url,NULL,NULL,
				      (NCURISTD ^ NCURICONSTRAINTS));

    /* Pass to OC */
    ocstat = oc_open(dapcomm->oc.urltext,&dapcomm->oc.conn);
    if(ocstat != OC_NOERR) {THROWCHK(ocstat); goto done;}

    nullfree(dapcomm->oc.urltext); /* clean up */
    dapcomm->oc.urltext = NULL;

    /* process control client parameters */
    applyclientparamcontrols3(dapcomm);

    /* Turn on logging; only do this after oc_open*/
    if((value = paramvalue34(dapcomm,"log")) != NULL) {
	ncloginit();
        if(nclogopen(value))
	    ncsetlogging(1);
	ocloginit();
        if(oclogopen(value))
	    ocsetlogging(1);
    }

    /* fetch and build the unconstrained DDS for use as
       template */
    ncstat = fetchtemplatemetadata3(dapcomm);
    if(ncstat != NC_NOERR) goto done;

    /* Operations on the template tree */

    /* Accumulate useful nodes sets  */
    ncstat = computecdfnodesets3(dapcomm,dapcomm->cdf.fullddsroot->tree);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* Define the dimsettrans list */
    ncstat = definedimsets3(dapcomm,dapcomm->cdf.fullddsroot->tree);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* Mark the nodes of the template that are eligible for prefetch */
    ncstat = markprefetch3(dapcomm);

    /* fetch and build the constrained DDS */
    ncstat = fetchconstrainedmetadata3(dapcomm);
    if(ncstat != NC_NOERR) goto done;

#ifdef DEBUG2
fprintf(stderr,"constrained dds: %s\n",dumptree(dapcomm->cdf.ddsroot));
#endif

    /* Operations on the constrained tree */

    /* Accumulate useful nodes sets  */
    ncstat = computecdfnodesets3(dapcomm,dapcomm->cdf.ddsroot->tree);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* Fix grids */
    ncstat = fixgrids3(dapcomm);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* Locate and mark usable sequences */
    ncstat = sequencecheck3(dapcomm);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* suppress variables not in usable sequences */
    ncstat = suppressunusablevars3(dapcomm);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* apply client parameters */
    ncstat = applyclientparams34(dapcomm);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* Add (as needed) string dimensions*/
    ncstat = addstringdims(dapcomm);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    if(nclistlength(dapcomm->cdf.ddsroot->tree->seqnodes) > 0) {
	/* Build the sequence related dimensions */
        ncstat = defseqdims(dapcomm);
        if(ncstat) {THROWCHK(ncstat); goto done;}
    }

    /* Define the dimsetplus and dimsetall lists */
    ncstat = definedimsets3(dapcomm,dapcomm->cdf.ddsroot->tree);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* Re-compute the dimension names*/
    ncstat = computecdfdimnames34(dapcomm);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* Deal with zero size dimensions */
    ncstat = fixzerodims3(dapcomm);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* Attempt to use the DODS_EXTRA info to turn
       one of the dimensions into unlimited.
       Assume computecdfdimnames34 has already been called.
    */
    ncstat = defrecorddim3(dapcomm);
    if(ncstat) {THROWCHK(ncstat); goto done;}
    if(dapcomm->cdf.recorddimname != NULL
       && nclistlength(dapcomm->cdf.ddsroot->tree->seqnodes) > 0) {
	/*nclog(NCLOGWARN,"unlimited dimension specified, but sequences exist in DDS");*/
	PANIC("unlimited dimension specified, but sequences exist in DDS");	
    }

    /* Re-compute the var names*/
    ncstat = computecdfvarnames3(dapcomm,
				 dapcomm->cdf.ddsroot,
				 dapcomm->cdf.ddsroot->tree->varnodes);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* Transfer data from the unconstrained DDS data to the unconstrained DDS */
    ncstat = dimimprint3(dapcomm);
    if(ncstat) goto done;

    /* Process the constraints to map to the constrained CDF tree */
    /* (must follow fixgrids3 */
    ncstat = mapconstraints3(dapcomm->oc.dapconstraint,dapcomm->cdf.ddsroot);
    if(ncstat != NC_NOERR) goto done;

    /* Canonicalize the constraint */
    ncstat = fixprojections(dapcomm->oc.dapconstraint->projections);
    if(ncstat != NC_NOERR) {THROWCHK(ncstat); goto done;}

    /* Fill in segment information */
    ncstat = qualifyconstraints3(dapcomm->oc.dapconstraint);
    if(ncstat != NC_NOERR) goto done;

    /* Accumulate set of variables in the constraint's projections */
    ncstat = computeprojectedvars(dapcomm,dapcomm->oc.dapconstraint);
    if(ncstat) {THROWCHK(ncstat); goto done;}

    /* using the modified constraint, rebuild the constraint string */
    if(FLAGSET(dapcomm->controls,NCF_UNCONSTRAINABLE)) {
	/* ignore all constraints */
	dapcomm->oc.urltext = ncuribuild(dapcomm->oc.url,NULL,NULL,0);
    } else {
	char* constraintstring = buildconstraintstring3(dapcomm->oc.dapconstraint);
        ncurisetconstraints(dapcomm->oc.url,constraintstring);
	nullfree(constraintstring);
        dapcomm->oc.urltext = ncuribuild(dapcomm->oc.url,NULL,NULL,NCURICONSTRAINTS);
    }

#ifdef DEBUG
fprintf(stderr,"ncdap3: final constraint: %s\n",dapcomm->oc.url->constraint);
#endif

    /* Estimate the variable sizes */
    estimatevarsizes3(dapcomm);

    /* Build the meta data */
    ncstat = buildncstructures3(dapcomm);
    if(ncstat != NC_NOERR) {THROWCHK(ncstat); goto done;}

    /* Explicitly do not call enddef because it will complain
       about variables that are too large.
    */
#if 0
    ncstat = nc_endef(drno->substrate,NC_NOFILL,NULL);
    if(ncstat != NC_NOERR && ncstat != NC_EVARSIZE)
        {THROWCHK(ncstat); goto done;}
#endif
	
    {
        NC* ncsub;
        NC* drno = dapcomm->controller;
	CDFnode* unlimited = dapcomm->cdf.recorddim;
        /* (for now) break abstractions*/
	NC3_INFO* nc3i;

        /* get the id for the substrate */
        ncstat = NC_check_id(drno->substrate,&ncsub);
        if(ncstat != NC_NOERR) {THROWCHK(ncstat); goto done;}
	nc3i = (NC3_INFO*)ncsub->dispatchdata;

        if(unlimited != NULL) {
            /* Set the effective size of UNLIMITED */
            NC_set_numrecs(nc3i,unlimited->dim.declsize);
        }

        /* Pretend the substrate is read-only */
	NC_set_readonly(nc3i);
	
    }

    /* Do any necessary data prefetch */
    if(FLAGSET(dapcomm->controls,NCF_PREFETCH)
       && FLAGSET(dapcomm->controls,NCF_PREFETCH_EAGER)) {
        ncstat = prefetchdata3(dapcomm);
        if(ncstat != NC_NOERR) {
            del_from_NCList((NC*)drno); /* undefine here */
	    {THROWCHK(ncstat); goto done;}
	}
    }

    return ncstat;

done:
    if(drno != NULL) NCD3_close(drno->ext_ncid);
    if(ocstat != OC_NOERR) ncstat = ocerrtoncerr(ocstat);
    return THROW(ncstat);
}

int
NCD3_close(int ncid)
{
    NC* drno;
    NCDAPCOMMON* dapcomm;
    int ncstatus = NC_NOERR;

    ncstatus = NC_check_id(ncid, (NC**)&drno); 
    if(ncstatus != NC_NOERR) return THROW(ncstatus);
    dapcomm = (NCDAPCOMMON*)drno->dispatchdata;

    /* We call abort rather than close to avoid
       trying to write anything or try to pad file length
     */
    ncstatus = nc_abort(drno->substrate);

    /* clean NC* */
    freeNCDAPCOMMON(dapcomm);

    return THROW(ncstatus);
}

/**************************************************/
static NCerror
buildncstructures3(NCDAPCOMMON* dapcomm)
{
    NCerror ncstat = NC_NOERR;
    CDFnode* dds = dapcomm->cdf.ddsroot;
    NC* ncsub;

    NC_check_id(dapcomm->controller->substrate,&ncsub);

    ncstat = buildglobalattrs3(dapcomm,dds);
    if(ncstat != NC_NOERR) goto done;

    ncstat = builddims(dapcomm);
    if(ncstat != NC_NOERR) goto done;

    ncstat = buildvars(dapcomm);
    if(ncstat != NC_NOERR) goto done;

done:
    return THROW(ncstat);
}

static NCerror
builddims(NCDAPCOMMON* dapcomm)
{
    int i;
    NCerror ncstat = NC_NOERR;
    int dimid;
    NClist* dimset = NULL;
    NC* drno = dapcomm->controller;
    NC* ncsub;
    char* definename;

    /* collect all dimensions from variables */
    dimset = dapcomm->cdf.ddsroot->tree->dimnodes;

    /* Sort by fullname just for the fun of it */
    for(;;) {
	int last = nclistlength(dimset) - 1;
	int swap = 0;
        for(i=0;i<last;i++) {
	    CDFnode* dim1 = (CDFnode*)nclistget(dimset,i);
	    CDFnode* dim2 = (CDFnode*)nclistget(dimset,i+1);
   	    if(strcmp(dim1->ncfullname,dim2->ncfullname) > 0) {
		nclistset(dimset,i,(void*)dim2);
		nclistset(dimset,i+1,(void*)dim1);
		swap = 1;
		break;
	    }
	}
	if(!swap) break;
    }

    /* Define unlimited only if needed */ 
    if(dapcomm->cdf.recorddim != NULL) {
	CDFnode* unlimited = dapcomm->cdf.recorddim;
	definename = getdefinename(unlimited);
        ncstat = nc_def_dim(drno->substrate,
			definename,
			NC_UNLIMITED,
			&unlimited->ncid);
	nullfree(definename);
        if(ncstat != NC_NOERR) {THROWCHK(ncstat); goto done;}

        /* get the id for the substrate */
        ncstat = NC_check_id(drno->substrate,&ncsub);
        if(ncstat != NC_NOERR) {THROWCHK(ncstat); goto done;}
#if 0
	nc3sub = (NC3_INFO*)&ncsub->dispatchdata;
        /* Set the effective size of UNLIMITED;
           note that this cannot easily be done thru the normal API.*/
        NC_set_numrecs(nc3sub,unlimited->dim.declsize);
#endif

    }

    for(i=0;i<nclistlength(dimset);i++) {
	CDFnode* dim = (CDFnode*)nclistget(dimset,i);
        if(dim->dim.basedim != NULL) continue; /* handle below */
	if(DIMFLAG(dim,CDFDIMRECORD)) continue; /* defined above */
#ifdef DEBUG1
fprintf(stderr,"define: dim: %s=%ld\n",dim->ncfullname,(long)dim->dim.declsize);
#endif
	definename = getdefinename(dim);
        ncstat = nc_def_dim(drno->substrate,definename,dim->dim.declsize,&dimid);
        if(ncstat != NC_NOERR) {
	    THROWCHK(ncstat); goto done;
	}
	nullfree(definename);
        dim->ncid = dimid;
    }

    /* Make all duplicate dims have same dimid as basedim*/
    /* (see computecdfdimnames)*/
    for(i=0;i<nclistlength(dimset);i++) {
	CDFnode* dim = (CDFnode*)nclistget(dimset,i);
        if(dim->dim.basedim != NULL) {
	    dim->ncid = dim->dim.basedim->ncid;
	}
    }
done:
    nclistfree(dimset);
    return THROW(ncstat);
}

/* Simultaneously build any associated attributes*/
/* and any necessary pseudo-dimensions for string types*/
static NCerror
buildvars(NCDAPCOMMON* dapcomm)
{
    int i,j;
    NCerror ncstat = NC_NOERR;
    int varid;
    NClist* varnodes = dapcomm->cdf.ddsroot->tree->varnodes;
    NC* drno = dapcomm->controller;
    char* definename;

    ASSERT((varnodes != NULL));
    for(i=0;i<nclistlength(varnodes);i++) {
	CDFnode* var = (CDFnode*)nclistget(varnodes,i);
        int dimids[NC_MAX_VAR_DIMS];
	unsigned int ncrank;
        NClist* vardims = NULL;

	if(var->invisible) continue;
	if(var->array.basevar != NULL) continue;

#ifdef DEBUG1
fprintf(stderr,"buildvars.candidate=|%s|\n",var->ncfullname);
#endif

	vardims = var->array.dimsetall;
	ncrank = nclistlength(vardims);
	if(ncrank > 0) {
            for(j=0;j<ncrank;j++) {
                CDFnode* dim = (CDFnode*)nclistget(vardims,j);
                dimids[j] = dim->ncid;
 	    }
        }   



	definename = getdefinename(var);

#ifdef DEBUG1
fprintf(stderr,"define: var: %s/%s",
		definename,var->ocname);
if(ncrank > 0) {
int k;
for(k=0;k<ncrank;k++) {
CDFnode* dim = (CDFnode*)nclistget(vardims,k);
fprintf(stderr,"[%ld]",dim->dim.declsize);
 }
 }
fprintf(stderr,"\n");
#endif
        ncstat = nc_def_var(drno->substrate,
		        definename,
                        var->externaltype,
                        ncrank,
                        (ncrank==0?NULL:dimids),
                        &varid);
	nullfree(definename);
        if(ncstat != NC_NOERR) {
	    THROWCHK(ncstat);
	    goto done;
	}
        var->ncid = varid;
	if(var->attributes != NULL) {
	    for(j=0;j<nclistlength(var->attributes);j++) {
		NCattribute* att = (NCattribute*)nclistget(var->attributes,j);
		ncstat = buildattribute3a(dapcomm,att,var->etype,varid);
        	if(ncstat != NC_NOERR) goto done;
	    }
	}
	/* Tag the variable with its DAP path */
	if(paramcheck34(dapcomm,"show","projection"))
	    showprojection3(dapcomm,var);
    }    
done:
    return THROW(ncstat);
}

static NCerror
buildglobalattrs3(NCDAPCOMMON* dapcomm, CDFnode* root)
{
    int i;
    NCerror ncstat = NC_NOERR;
    const char* txt;
    char *nltxt, *p;
    NCbytes* buf = NULL;
    NClist* cdfnodes;
    NC* drno = dapcomm->controller;

    if(root->attributes != NULL) {
        for(i=0;i<nclistlength(root->attributes);i++) {
   	    NCattribute* att = (NCattribute*)nclistget(root->attributes,i);
	    ncstat = buildattribute3a(dapcomm,att,NC_NAT,NC_GLOBAL);
            if(ncstat != NC_NOERR) goto done;
	}
    }

    /* Add global attribute identifying the sequence dimensions */
    if(paramcheck34(dapcomm,"show","seqdims")) {
        buf = ncbytesnew();
        cdfnodes = dapcomm->cdf.ddsroot->tree->nodes;
        for(i=0;i<nclistlength(cdfnodes);i++) {
	    CDFnode* dim = (CDFnode*)nclistget(cdfnodes,i);
	    if(dim->nctype != NC_Dimension) continue;
	    if(DIMFLAG(dim,CDFDIMSEQ)) {
	        char* cname = cdflegalname3(dim->ocname);
	        if(ncbyteslength(buf) > 0) ncbytescat(buf,", ");
	        ncbytescat(buf,cname);
	        nullfree(cname);
	    }
	}
        if(ncbyteslength(buf) > 0) {
            ncstat = nc_put_att_text(drno->substrate,NC_GLOBAL,"_sequence_dimensions",
	           ncbyteslength(buf),ncbytescontents(buf));
	}
    }

    /* Define some additional system global attributes
       depending on show= clientparams*/
    /* Ignore failures*/

    if(paramcheck34(dapcomm,"show","translate")) {
        /* Add a global attribute to show the translation */
        ncstat = nc_put_att_text(drno->substrate,NC_GLOBAL,"_translate",
	           strlen("netcdf-3"),"netcdf-3");
    }
    if(paramcheck34(dapcomm,"show","url")) {
	if(dapcomm->oc.rawurltext != NULL)
            ncstat = nc_put_att_text(drno->substrate,NC_GLOBAL,"_url",
				       strlen(dapcomm->oc.rawurltext),dapcomm->oc.rawurltext);
    }
    if(paramcheck34(dapcomm,"show","dds")) {
	txt = NULL;
	if(dapcomm->cdf.ddsroot != NULL)
  	    txt = oc_tree_text(dapcomm->oc.conn,dapcomm->cdf.ddsroot->ocnode);
	if(txt != NULL) {
	    /* replace newlines with spaces*/
	    nltxt = nulldup(txt);
	    for(p=nltxt;*p;p++) {if(*p == '\n' || *p == '\r' || *p == '\t') {*p = ' ';}};
            ncstat = nc_put_att_text(drno->substrate,NC_GLOBAL,"_dds",strlen(nltxt),nltxt);
	    nullfree(nltxt);
	}
    }
    if(paramcheck34(dapcomm,"show","das")) {
	txt = NULL;
	if(dapcomm->oc.ocdasroot != NULL)
	    txt = oc_tree_text(dapcomm->oc.conn,dapcomm->oc.ocdasroot);
	if(txt != NULL) {
	    nltxt = nulldup(txt);
	    for(p=nltxt;*p;p++) {if(*p == '\n' || *p == '\r' || *p == '\t') {*p = ' ';}};
            ncstat = nc_put_att_text(drno->substrate,NC_GLOBAL,"_das",strlen(nltxt),nltxt);
	    nullfree(nltxt);
	}
    }

done:
    ncbytesfree(buf);
    return THROW(ncstat);
}

static NCerror
buildattribute3a(NCDAPCOMMON* dapcomm, NCattribute* att, nc_type vartype, int varid)
{
    int i;
    NCerror ncstat = NC_NOERR;
    unsigned int nvalues = nclistlength(att->values);
    NC* drno = dapcomm->controller;

    /* If the type of the attribute is string, then we need*/
    /* to convert to a single character string by concatenation.
	modified: 10/23/09 to insert newlines.
	modified: 10/28/09 to interpret escapes
    */
    if(att->etype == NC_STRING || att->etype == NC_URL) {
	char* newstring;
	size_t newlen = 0;
	for(i=0;i<nvalues;i++) {
	    char* s = (char*)nclistget(att->values,i);
	    newlen += (1+strlen(s));
	}
	newstring = (char*)malloc(newlen);
        MEMCHECK(newstring,NC_ENOMEM);
	newstring[0] = '\0';
	for(i=0;i<nvalues;i++) {
	    char* s = (char*)nclistget(att->values,i);
	    if(i > 0) strcat(newstring,"\n");
	    strcat(newstring,s);
	}
        dapexpandescapes(newstring);
	if(newstring[0]=='\0')
	    ncstat = nc_put_att_text(drno->substrate,varid,att->name,1,newstring);
	else
	    ncstat = nc_put_att_text(drno->substrate,varid,att->name,strlen(newstring),newstring);
	free(newstring);
    } else {
	nc_type atype;
	unsigned int typesize;
	void* mem;
	/* It turns out that some servers upgrade the type
           of _FillValue in order to correctly preserve the
           original value. However, since the type of the
           underlying variable is not changes, we get a type
           mismatch. So, make sure the type of the fillvalue
           is the same as that of the controlling variable.
	*/
        if(varid != NC_GLOBAL && strcmp(att->name,"_FillValue")==0)
	    atype = nctypeconvert(dapcomm,vartype);
	else
	    atype = nctypeconvert(dapcomm,att->etype);
	typesize = nctypesizeof(atype);
	mem = malloc(typesize * nvalues);
        ncstat = dapcvtattrval3(atype,mem,att->values);
        ncstat = nc_put_att(drno->substrate,varid,att->name,atype,nvalues,mem);
	nullfree(mem);
    }
    return THROW(ncstat);
}

static char*
getdefinename(CDFnode* node)
{
    char* spath = NULL;
    NClist* path = NULL;

    switch (node->nctype) {
    case NC_Atomic:
	/* The define name is same as the fullname with elided nodes */
	path = nclistnew();
        collectnodepath3(node,path,!WITHDATASET);
        spath = makepathstring3(path,".",PATHNC|PATHELIDE);
        nclistfree(path);
	break;

    case NC_Dimension:
	/* Return just the node's ncname */
	spath = nulldup(node->ncbasename);	
	break;

    default:
	PANIC("unexpected nctype");
    }
    return spath;
}

int
NCDAP_ping(const char* url)
{
    OCerror ocstat = OC_NOERR;
    ocstat = oc_ping(url);
    return ocerrtoncerr(ocstat);
}