NCArray.cc

// -*- mode: c++; c-basic-offset:4 -*-
 
// This file is part of nc_handler, a data handler for the OPeNDAP data
// server.
 
// Copyright (c) 2002,2003 OPeNDAP, Inc.
// Author: James Gallagher <jgallagher@opendap.org>
//
// This is free software; you can redistribute it and/or modify it under the
// terms of the GNU Lesser General Public License as published by the Free
// Software Foundation; either version 2.1 of the License, or (at your
// option) any later version.
//
// This software is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
// License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//
// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.
 
// (c) COPYRIGHT URI/MIT 1994-1999
// Please read the full copyright statement in the file COPYRIGHT.
//
// Authors:
//      reza            Reza Nekovei (rnekovei@ieee.org)
 
// netCDF sub-class implementation for NCByte,...NCGrid.
// The files are patterned after the subcalssing examples
// Test<type>.c,h files.
//
// ReZa 1/12/95
 
#include "config_nc.h"
 
#include <cstring>
#include <iostream>
#include <sstream>
#include <algorithm>
 
#include <netcdf.h>
 
// #define DODS_DEBUG 1
 
#include <libdap/BaseType.h>
#include <libdap/Error.h>
#include <libdap/InternalErr.h>
#include <libdap/util.h>
#include <libdap/debug.h>
 
#include <BESDebug.h>
 
#include "NCRequestHandler.h"
#include "NCArray.h"
#include "NCStructure.h"
// #include "nc_util.h"
 
#define MODULE "nc"
#define prolog std::string("NCArray::").append(__func__).append("() - ")
 
BaseType *
NCArray::ptr_duplicate()
{
    return new NCArray(*this);
}
 
NCArray::NCArray(const string &n, const string &d, BaseType *v)
    : Array(n, d, v)
{}
 
NCArray::NCArray(const NCArray &rhs) : Array(rhs)
{}
 
NCArray::~NCArray()
{
}
 
NCArray &
NCArray::operator=(const NCArray &rhs)
{
    if (this == &rhs)
        return *this;
 
    dynamic_cast<Array &>(*this) = rhs;
 
    return *this;
}
 
 
// Should this be a private method? jhrg 11/3/04
long
NCArray::format_constraint(size_t *cor, ptrdiff_t *step, size_t *edg,
                           bool *has_stride)
{
    int start, stride, stop;
    int id = 0;
    long nels = 1;
 
    *has_stride = false;
 
    for (Dim_iter p = dim_begin(); p != dim_end(); ++p) {
        start = dimension_start(p, true);
        stride = dimension_stride(p, true);
        stop = dimension_stop(p, true);
#if 0
        // Check for an empty constraint and use the whole dimension if so.
        if (start + stop + stride == 0) {
            start = dimension_start(p, false);
            stride = dimension_stride(p, false);
            stop = dimension_stop(p, false);
        }
#endif
        cor[id] = start;
        step[id] = stride;
        edg[id] = ((stop - start) / stride) + 1; // count of elements
        nels *= edg[id++];      // total number of values for variable
 
        if (stride != 1)
            *has_stride = true;
    }
 
    return nels;
}
 
void NCArray::do_cardinal_array_read(int ncid, int varid, nc_type datatype,
        vector<char> &values, bool has_values, int values_offset,
        int nels, size_t cor[], size_t edg[], ptrdiff_t step[], bool has_stride)
{
    size_t size;
    int errstat;
#if NETCDF_VERSION >= 4
    errstat = nc_inq_type(ncid, datatype, 0, &size);
    if (errstat != NC_NOERR)
        throw Error(errstat, "Could not get the size for the type.");
#else
    size = nctypelen(datatype);
#endif
 
    BESDEBUG( MODULE, prolog << "size = " << size << endl);
    switch (datatype) {
        case NC_FLOAT:
        case NC_DOUBLE:
        case NC_SHORT:
        case NC_INT:
#if NETCDF_VERSION >= 4
        case NC_USHORT:
        case NC_UINT:
        case NC_UBYTE:
#endif
        {
            if (!has_values) {
                values.resize(nels * size);
                if (has_stride)
                    errstat = nc_get_vars(ncid, varid, cor, edg, step, values.data());
                else
                    errstat = nc_get_vara(ncid, varid, cor, edg, values.data());
                if (errstat != NC_NOERR){
                        ostringstream oss;
                        oss << prolog << "Could not get the value for Array variable '" << name() << "'.";
                        oss << " dimensions: " << dimensions(true);
                        oss << " nc_get_vara() errstat: " << errstat;
                    throw Error(errstat, oss.str());
                }
                // Do not set has_values to true here because the 'true' state
                // indicates that the values for an entire compound have been
                // read.
            }
 
            val2buf(values.data() + values_offset);
            set_read_p(true);
            break;
        }
 
        case NC_BYTE:{
            if (!has_values) {
                values.resize(nels * size);
                if (has_stride)
                    errstat = nc_get_vars(ncid, varid, cor, edg, step, values.data());
                else
                    errstat = nc_get_vara(ncid, varid, cor, edg, values.data());
                if (errstat != NC_NOERR)
                    throw Error(errstat, prolog + "Could not get the value for variable '" + name() + string("' (NCArray::do_cardinal_array_read)"));
            }
            if (NCRequestHandler::get_promote_byte_to_short()) {
                // the data set's signed byte data are going to be stored in a short
                // not an unsigned byte array. But double check that the template
                // data type is Int16.
                if (var()->type() != libdap::dods_int16_c) {
                    throw Error(string("NC.PromoteByteToShort is set but the underlying array type is still a Byte: ") + name() + string("."));
                }
                // temporary vector for short (int16) data
                vector<short int> tmp(nels);
 
                // Pointer into the byte data. These values might be part of a compound and
                // thus might have been read by a previous call (has_values is true in that
                // case).
                const char *raw_byte_data = values.data() + values_offset;
                for (int i = 0; i < nels; ++i)
                    tmp[i] = *raw_byte_data++;
                val2buf(tmp.data());
                set_read_p(true);
            }
            else {
                val2buf(values.data() + values_offset);
                set_read_p(true);
            }
            break;
        }
 
        case NC_CHAR: {
            // Use the dimension info from netcdf since that's the place where
            // this variable has N-dims. In the DAP representation it's a N-1
            // dimensional variable.
            int num_dim;                // number of dim. in variable
            int vdimids[MAX_VAR_DIMS];  // variable dimension ids
            errstat = nc_inq_var(ncid, varid, (char *)0, (nc_type*)0, &num_dim, vdimids, (int *)0);
            if (errstat != NC_NOERR)
                throw Error(errstat, string("Could not read information about the variable `") + name() + string("'."));
            if (num_dim < 2)    // one-dim --> DAP String and we should not be here
                throw Error(string("A one-dimensional NC_CHAR array should now map to a DAP string: '") + name() + string("'."));
 
            size_t vdims[MAX_VAR_DIMS]; // variable dimension sizes
            for (int i = 0; i < num_dim; ++i)
                if ((errstat = nc_inq_dimlen(ncid, vdimids[i], &vdims[i])) != NC_NOERR)
                    throw Error(errstat, string("Could not read dimension information about the variable `") + name() + string("'."));
 
            int nth_dim_size = vdims[num_dim - 1];
            cor[num_dim - 1] = 0;
            edg[num_dim - 1] = nth_dim_size;
            if (has_stride)
                step[num_dim - 1] = 1;
 
            if (!has_values) {
                values.resize(nels * nth_dim_size * size);
                if (has_stride)
                    errstat = nc_get_vars_text(ncid, varid, cor, edg, step, values.data());
                else
                    errstat = nc_get_vara_text(ncid, varid, cor, edg, values.data());
                if (errstat != NC_NOERR)
                    throw Error(errstat, string("Could not read the variable '") + name() + string("'."));
            }
 
            // How large is the Nth dimension? Allocate space for the N-1 dims.
            vector<string> strg(nels);
            vector<char> buf(nth_dim_size + 1);
            // put the char values in the string array
            for (int i = 0; i < nels; i++) {
                strncpy(buf.data(), values.data() + values_offset + (i * nth_dim_size), nth_dim_size);
                buf[nth_dim_size] = '\0';
                strg[i] = buf.data();
            }
 
            set_read_p(true);
            val2buf(strg.data());
            break;
        }
#if NETCDF_VERSION >= 4
        case NC_STRING: {
            if (!has_values) {
                values.resize(nels * size);
                if (has_stride)
                    errstat = nc_get_vars_string(ncid, varid, cor, edg, step, (char**)(values.data() + values_offset));
                else
                    errstat = nc_get_vara_string(ncid, varid, cor, edg, (char**)(values.data() + values_offset));
                if (errstat != NC_NOERR)
                    throw Error(errstat, string("Could not read the variable `") + name() + string("'."));
            }
 
            // put the char values in the string array
            vector < string > strg(nels);
            for (int i = 0; i < nels; i++) {
                // values_offset is in bytes; then cast to char** to find the
                // ith element; then dereference to get the C-style string.
                strg[i] = *((char**)(values.data() + values_offset) + i);
            }
 
            nc_free_string(nels, (char**)values.data());
            set_read_p(true);
            val2buf(strg.data());
            break;
        }
#endif
        default:
            throw InternalErr(__FILE__, __LINE__, string("Unknown data type for the variable '") + name() + string("'."));
    }
}
 
void NCArray::do_array_read(int ncid, int varid, nc_type datatype,
        vector<char> &values, bool has_values, int values_offset,
        int nels, size_t cor[], size_t edg[], ptrdiff_t step[], bool has_stride)
{
    int errstat;
 
#if NETCDF_VERSION >= 4
    if (datatype >= NC_FIRSTUSERTYPEID /*is_user_defined_type(ncid, datatype)*/) {
        // datatype >= NC_FIRSTUSERTYPEID) {
        char type_name[NC_MAX_NAME+1];
        size_t size;
        nc_type base_type;
        size_t nfields;
        int class_type;
        errstat = nc_inq_user_type(ncid, datatype, type_name, &size, &base_type, &nfields, &class_type);
        //cerr << "User-defined attribute type size: " << size << ", nfields: " << nfields << endl;
        if (errstat != NC_NOERR)
            throw(InternalErr(__FILE__, __LINE__, "Could not get information about a user-defined type (" + long_to_string(errstat) + ")."));
 
        switch (class_type) {
            case NC_COMPOUND: {
                if (!has_values) {
                    values.resize(size * nels);
                    if (has_stride)
                        errstat = nc_get_vars(ncid, varid, cor, edg, step, values.data());
                    else
                        errstat = nc_get_vara(ncid, varid, cor, edg, values.data());
                    if (errstat != NC_NOERR)
                        throw Error(errstat, string("Could not get the value for variable '") + name() + string("'"));
                    has_values = true;
                }
 
                for (int element = 0; element < nels; ++element) {
                    NCStructure *ncs = dynamic_cast<NCStructure*> (var()->ptr_duplicate());
                    for (int i = 0; i < nfields; ++i) {
                        char field_name[NC_MAX_NAME+1];
                        nc_type field_typeid;
                        size_t field_offset;
                        // These are unused... should they be used?
                        // int field_ndims;
                        // int field_sizes[MAX_NC_DIMS];
                        nc_inq_compound_field(ncid, datatype, i, field_name, &field_offset, &field_typeid, nullptr, nullptr); //&field_ndims, field_sizes.data());
                        BaseType *field = ncs->var(field_name);
                        if (field_typeid >= NC_FIRSTUSERTYPEID /*is_user_defined_type(ncid, field_typeid)*/) {
                            // Interior user defined types have names, but not field_names
                            // so use the type name as the field name (matches the
                            // behavior of the ncdds.cc code).
                            nc_inq_compound_name(ncid, field_typeid, field_name);
                            field = ncs->var(field_name);
                            NCStructure &child_ncs = dynamic_cast<NCStructure&> (*field);
                            child_ncs.do_structure_read(ncid, varid, field_typeid,
                                    values, has_values, field_offset + values_offset + size * element);
                        }
                        else if (field->is_vector_type()) {
                            // Because the netcdf api reads data 'atomically' from
                            // compounds, this call works for both cardinal and
                            // array variables.
                            NCArray &child_array = dynamic_cast<NCArray&>(*field);
                            child_array.do_array_read(ncid, varid, field_typeid,
                                    values, has_values, field_offset + values_offset + size * element,
                                    nels, cor, edg, step, has_stride);
                        }
                        else if (field->is_simple_type()) {
                            field->val2buf(values.data() + (element * size) + field_offset);
                        }
                        else {
                            throw InternalErr(__FILE__, __LINE__, "Expecting a netcdf user defined type or an array or a scalar.");
                        }
 
                        field->set_read_p(true);
                    }
                    ncs->set_read_p(true);
                    set_vec(element, ncs);
                }
 
                set_read_p(true);
                break;
            }
 
            case NC_VLEN:
                if (NCRequestHandler::get_ignore_unknown_types())
                    cerr << "in build_user_defined; found a vlen." << endl;
                else
                    throw Error("The netCDF handler does not currently support NC_VLEN attributes.");
                break;
 
            case NC_OPAQUE: {
                // Use the dimension info from netcdf since that's the place where
                // this variable has N-dims. In the DAP representation it's a N-1
                // dimensional variable.
                int num_dim;                // number of dim. in variable
                int vdimids[MAX_VAR_DIMS];  // variable dimension ids
                errstat = nc_inq_var(ncid, varid, (char *)0, (nc_type*)0, &num_dim, vdimids, (int *)0);
                if (errstat != NC_NOERR)
                    throw Error(errstat, string("Could not read information about the variable `") + name() + string("'."));
                if (num_dim < 1)    // one-dim --> DAP String and we should not be here
                    throw Error(string("A one-dimensional NC_OPAQUE array should now map to a DAP Byte: '") + name() + string("'."));
 
                size_t vdims[MAX_VAR_DIMS]; // variable dimension sizes
                for (int i = 0; i < num_dim; ++i)
                    if ((errstat = nc_inq_dimlen(ncid, vdimids[i], &vdims[i])) != NC_NOERR)
                        throw Error(errstat, string("Could not read dimension information about the variable `") + name() + string("'."));
 
                int nth_dim_size = vdims[num_dim - 1];
                cor[num_dim - 1] = 0;
                edg[num_dim - 1] = nth_dim_size;
                if (has_stride)
                    step[num_dim - 1] = 1;
 
                if (!has_values) {
                     values.resize(size * nels);
                     if (has_stride)
                         errstat = nc_get_vars(ncid, varid, cor, edg, step, values.data());
                     else
                         errstat = nc_get_vara(ncid, varid, cor, edg, values.data());
                     if (errstat != NC_NOERR)
                         throw Error(errstat, string("Could not get the value for variable '") + name() + string("' (NC_OPAQUE)"));
                     has_values = true; // This value may never be used. jhrg 1/9/12
                 }
 
                 val2buf(values.data() + values_offset);
 
                set_read_p(true);
                break;
            }
 
            case NC_ENUM: {
                nc_type base_nc_type;
                errstat = nc_inq_enum(ncid, datatype, nullptr /*name.data()*/, &base_nc_type, nullptr/*&base_size*/, nullptr/*&num_members*/);
                if (errstat != NC_NOERR)
                    throw(InternalErr(__FILE__, __LINE__, "Could not get information about an enum(" + long_to_string(errstat) + ")."));
 
                do_cardinal_array_read(ncid, varid, base_nc_type,
                        values, has_values, values_offset,
                        nels, cor, edg, step, has_stride);
 
                set_read_p(true);
                break;
            }
 
            default:
                throw InternalErr(__FILE__, __LINE__, "Expected one of NC_COMPOUND, NC_VLEN, NC_OPAQUE or NC_ENUM");
        }
 
    }
    else {
        do_cardinal_array_read(ncid, varid, datatype, values, has_values, values_offset,
                nels, cor, edg, step, has_stride);
    }
#else
        do_cardinal_array_read(ncid, varid, datatype, values, has_values, values_offset,
                nels, cor, edg, step, has_stride);
#endif
}
 
bool NCArray::read()
{
    if (read_p())  // Nothing to do
        return true;
 
    int ncid;
    int errstat = nc_open(dataset().c_str(), NC_NOWRITE, &ncid); /* netCDF id */
    if (errstat != NC_NOERR)
        throw Error(errstat, string("Could not open the dataset's file (") + dataset().c_str() + string(")"));
 
    int varid;                  /* variable Id */
    errstat = nc_inq_varid(ncid, name().c_str(), &varid);
    if (errstat != NC_NOERR)
        throw InternalErr(__FILE__, __LINE__, "Could not get variable ID for: " + name() + ". (error: " + long_to_string(errstat) + ").");
 
    nc_type datatype;           // variable data type
    errstat = nc_inq_vartype(ncid, varid, &datatype);
    if (errstat != NC_NOERR)
        throw Error(errstat, string("Could not read information about the variable `") + name() + string("'."));
 
    size_t cor[MAX_NC_DIMS];      /* corner coordinates */
    size_t edg[MAX_NC_DIMS];      /* edges of hyper-cube */
    ptrdiff_t step[MAX_NC_DIMS];  /* stride of hyper-cube */
    bool has_stride;
    for(unsigned int i=0; i<MAX_NC_DIMS; i++){
                cor[i] = edg[i] = step[i] = 0;
    }
    long nels = format_constraint(cor, step, edg, &has_stride);
//    ostringstream oss;
//    for(unsigned int i=0; i<MAX_NC_DIMS; i++){
//      oss << cor[i] <<  ", " << edg[i] << ", " << step[i] << endl;
//    }
//    BESDEBUG( MODULE, prolog << "corners, edges, stride" << endl << oss.str() << endl);
 
    vector<char> values;
    do_array_read(ncid, varid, datatype, values, false /*has_values*/, 0 /*values_offset*/,
            nels, cor, edg, step, has_stride);
    set_read_p(true);
 
    if (nc_close(ncid) != NC_NOERR)
        throw InternalErr(__FILE__, __LINE__, "Could not close the dataset!");
 
    return true;
}