netcdf-c/libdap4/d4swap.c
Dennis Heimbigner 65414eeaa4 Fix some protocol differences between netcdf-c and the Hyrax server.
re: Partly addresses issue https://github.com/Unidata/netcdf-c/issues/1712.

1. Turn on Hyrax Hack to accept Hyrax style attribute containers.
2. Support Url type as alias for String.
3. Accept the special attribute, "__DAP4_Checksum_CRC32",
   to control per-variable checksums.
4. Make _DAP4_xxx attributes be reserved and only accessible
   by name (ala _SuperBlock attribute).
5. Fix handling of checksums. There is a hack in the code
   that uses an extra flag in the chunk header to indicate
   that all variables have checksums. This violates the spec
   and will be removed once it is possible to regenerate the
   test cases.

Note that checksumming with the Hyrax test server has not
been tested. This, along with some other probable inconsistencies,
needs fixing when OPeNDAP and Unidata can agree on the proper
specification. Testing will be included.
2020-05-30 17:36:25 -06:00

261 lines
7.0 KiB
C

/*********************************************************************
* Copyright 2018, UCAR/Unidata
* See netcdf/COPYRIGHT file for copying and redistribution conditions.
*********************************************************************/
#include "d4includes.h"
#include <stdarg.h>
#include "d4includes.h"
#include "ezxml.h"
/*
The primary purpose of this code is to recursively traverse
the incoming data to get the endianness correct.
*/
/* Forward */
static int walkAtomicVar(NCD4meta*, NCD4node*, NCD4node*, void** offsetp);
static int walkOpaqueVar(NCD4meta*,NCD4node*, NCD4node*, void** offsetp);
static int walkStructArray(NCD4meta*,NCD4node*, NCD4node*, void** offsetp);
static int walkStruct(NCD4meta*, NCD4node*, NCD4node*, void** offsetp);
static int walkSeqArray(NCD4meta*, NCD4node*, NCD4node*, void** offsetp);
static int walkSeq(NCD4meta*,NCD4node*, NCD4node*, void** offsetp);
/**************************************************/
/*
Assumes that compiler->swap is true; does necessary
byte swapping.
*/
int
NCD4_swapdata(NCD4meta* compiler, NClist* topvars)
{
int ret = NC_NOERR;
int i;
void* offset;
offset = compiler->serial.dap;
for(i=0;i<nclistlength(topvars);i++) {
NCD4node* var = (NCD4node*)nclistget(topvars,i);
var->data.dap4data.memory = offset;
switch (var->subsort) {
default:
if((ret=walkAtomicVar(compiler,var,var,&offset))) goto done;
break;
case NC_OPAQUE:
/* The only thing we need to do is swap the counts */
if((ret=walkOpaqueVar(compiler,var,var,&offset))) goto done;
break;
case NC_STRUCT:
if((ret=walkStructArray(compiler,var,var,&offset))) goto done;
break;
case NC_SEQ:
if((ret=walkSeqArray(compiler,var,var,&offset))) goto done;
break;
}
var->data.dap4data.size = DELTA(offset,var->data.dap4data.memory);
/* skip checksum, if there is one */
if(var->data.remotechecksummed)
offset = INCR(offset,CHECKSUMSIZE);
}
done:
return THROW(ret);
}
static int
walkAtomicVar(NCD4meta* compiler, NCD4node* topvar, NCD4node* var, void** offsetp)
{
int ret = NC_NOERR;
void* offset;
d4size_t i;
nc_type subsort;
d4size_t dimproduct;
NCD4node* basetype;
basetype = (var->sort == NCD4_TYPE ? var : var->basetype);
subsort = basetype->subsort;
dimproduct = (var->sort == NCD4_TYPE ? 1 : NCD4_dimproduct(var));
offset = *offsetp;
if(subsort == NC_ENUM)
subsort = var->basetype->basetype->subsort;
/* Only need to swap multi-byte integers and floats */
if(subsort != NC_STRING) {
int typesize = NCD4_typesize(subsort);
d4size_t totalsize = typesize*dimproduct;
if(typesize == 1) {
offset = INCR(offset,totalsize);
} else { /*(typesize > 1)*/
for(i=0;i<dimproduct;i++) {
char* sp = (char*)offset;
if(compiler->swap) {
switch (typesize) {
case 2: swapinline16(sp); break;
case 4: swapinline32(sp); break;
case 8: swapinline64(sp); break;
default: break;
}
}
offset = INCR(offset,typesize);
}
}
} else if(subsort == NC_STRING) { /* remaining case; just convert the counts */
COUNTERTYPE count;
for(i=0;i<dimproduct;i++) {
/* Get string count */
if(compiler->swap)
swapinline64(offset);
count = GETCOUNTER(offset);
SKIPCOUNTER(offset);
/* skip count bytes */
offset = INCR(offset,count);
}
}
*offsetp = offset;
return THROW(ret);
}
static int
walkOpaqueVar(NCD4meta* compiler, NCD4node* topvar, NCD4node* var, void** offsetp)
{
int ret = NC_NOERR;
void* offset;
d4size_t i;
unsigned long long count;
d4size_t dimproduct = NCD4_dimproduct(var);
dimproduct = (var->sort == NCD4_TYPE ? 1 : NCD4_dimproduct(var));
offset = *offsetp;
for(i=0;i<dimproduct;i++) {
/* Get and swap opaque count */
if(compiler->swap)
swapinline64(offset);
count = GETCOUNTER(offset);
SKIPCOUNTER(offset);
offset = INCR(offset,count);
}
*offsetp = offset;
return THROW(ret);
}
static int
walkStructArray(NCD4meta* compiler, NCD4node* topvar, NCD4node* var, void** offsetp)
{
int ret = NC_NOERR;
void* offset;
d4size_t i;
d4size_t dimproduct = NCD4_dimproduct(var);
NCD4node* basetype = var->basetype;
offset = *offsetp;
for(i=0;i<dimproduct;i++) {
/* Swap, possibly recursively, the single struct pointed to by offset*/
if((ret=walkStruct(compiler,topvar,basetype,&offset))) goto done;
}
*offsetp = offset;
done:
return THROW(ret);
}
static int
walkStruct(NCD4meta* compiler, NCD4node* topvar, NCD4node* structtype, void** offsetp)
{
int ret = NC_NOERR;
int i;
void* offset;
offset = *offsetp;
for(i=0;i<nclistlength(structtype->vars);i++) {
NCD4node* field = (NCD4node*)nclistget(structtype->vars,i);
NCD4node* fieldbase = field->basetype;
switch (fieldbase->subsort) {
default:
if((ret=walkAtomicVar(compiler,topvar,field,&offset))) goto done;
break;
case NC_OPAQUE:
/* The only thing we need to do is swap the counts */
if((ret=walkOpaqueVar(compiler,topvar,field,&offset))) goto done;
break;
case NC_STRUCT:
if((ret=walkStructArray(compiler,topvar,field,&offset))) goto done;
break;
case NC_SEQ:
if((ret=walkSeqArray(compiler,topvar,field,&offset))) goto done;
break;
}
}
*offsetp = offset;
done:
return THROW(ret);
}
static int
walkSeqArray(NCD4meta* compiler, NCD4node* topvar, NCD4node* var, void** offsetp)
{
int ret = NC_NOERR;
void* offset;
d4size_t i;
d4size_t dimproduct;
NCD4node* seqtype;
assert(var->sort == NCD4_VAR);
dimproduct = NCD4_dimproduct(var);
seqtype = var->basetype;
offset = *offsetp;
for(i=0;i<dimproduct;i++) {
/* Swap, possibly recursively, the single seq pointed to by offset*/
if((ret=walkSeq(compiler,topvar,seqtype,&offset))) goto done;
}
*offsetp = offset;
done:
return THROW(ret);
}
/*
Remember that the base type of var is a vlen.
*/
static int
walkSeq(NCD4meta* compiler, NCD4node* topvar, NCD4node* vlentype, void** offsetp)
{
int ret = NC_NOERR;
int i;
void* offset;
d4size_t recordcount;
NCD4node* basetype;
offset = *offsetp;
/* process the record count */
if(compiler->swap)
swapinline64(offset);
recordcount = GETCOUNTER(offset);
SKIPCOUNTER(offset);
basetype = vlentype->basetype; /* This may be of any type potentially */
assert(basetype->sort == NCD4_TYPE);
for(i=0;i<recordcount;i++) {
switch(basetype->subsort) {
default: /* atomic basetype */
if((ret=walkAtomicVar(compiler,topvar,basetype,&offset))) goto done;
break;
case NC_OPAQUE:
if((ret=walkOpaqueVar(compiler,topvar,basetype,&offset))) goto done;
break;
case NC_STRUCT:
/* We can treat each record like a structure instance */
if((ret=walkStruct(compiler,topvar,basetype,&offset))) goto done;
break;
case NC_SEQ:
if((ret=walkSeq(compiler,topvar,basetype,&offset))) goto done;
break;
}
}
*offsetp = offset;
done:
return THROW(ret);
}