grid_utils.cc

// -*- mode: c++; c-basic-offset:4 -*-

// This file is part of libdap, A C++ implementation of the OPeNDAP Data
// Access Protocol.

// Copyright (c) 2002,2003 OPeNDAP, Inc.
// Author: Nathan Potter <npotter@opendap.org>
//
// This library 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 library 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.

#include "config.h"

#include <BaseType.h>
#include <Structure.h>
#include <Grid.h>
#include <util.h>

#include <debug.h>

#include "grid_utils.h"
#include "gse_parser.h"
#include "GSEClause.h"

#if 0
#include "GridGeoConstraint.h"
#endif

using namespace libdap;

int gse_parse(functions::gse_arg *arg);
void gse_restart(FILE * in);

// Glue routines declared in gse.lex
void gse_delete_buffer(void *buffer);
void *gse_string(const char *yy_str);

namespace functions {

void get_grids(BaseType *bt, vector<Grid *> *grids)
{
    switch (bt->type()) {

    case dods_grid_c: {
        // Yay! It's a Grid!
        grids->push_back(static_cast<Grid*>(bt));
        break;
    }
    case dods_structure_c: {
        // It's an Structure - but of what? Check each variable in the Structure.
        Structure &s = static_cast<Structure&>(*bt);
        for (Structure::Vars_iter i = s.var_begin(); i != s.var_begin(); i++) {
            get_grids(*i, grids);
        }
        break;
    }
    // Grids cannot be members of Array or Sequence in DAP2. jhrg 6/10/13
    case dods_array_c:
    case dods_sequence_c:
    default:
        break;
    }
}

void get_grids(DDS &dds, vector<Grid *> *grids)
{
    for (DDS::Vars_iter i = dds.var_begin(); i != dds.var_end(); i++) {
        get_grids(*i, grids);
    }
}

#if 0

// Hacked this out of the code to get prototype value-based subsetting
// into the code. We might add it back later (or maybe there is a better
// place? jhrg 4/18/19

bool is_geo_grid(Grid *grid)
{
    try {
        GridGeoConstraint gc(grid);
    }
    catch (Error *e) {
        return false;
    }

    return true;
}
#endif

void parse_gse_expression(gse_arg *arg, BaseType *expr)
{
    gse_restart(0); // Restart the scanner.
    void *cls = gse_string(extract_string_argument(expr).c_str());
    // gse_switch_to_buffer(cls); // Get set to scan the string.
    bool status = gse_parse(arg) == 0;
    gse_delete_buffer(cls);
    if (!status)
        throw Error(malformed_expr, "Error parsing grid selection.");
}

static void apply_grid_selection_expr(Grid *grid, GSEClause *clause)
{
    // Basic plan: For each map, look at each clause and set start and stop
    // to be the intersection of the ranges in those clauses.
    Grid::Map_iter map_i = grid->map_begin();
    while (map_i != grid->map_end() && (*map_i)->name() != clause->get_map_name())
        ++map_i;

    if (map_i == grid->map_end())
        throw Error(malformed_expr,"The map vector '" + clause->get_map_name()
                + "' is not in the grid '" + grid->name() + "'.");

    // Use pointer arith & the rule that map order must match array dim order
    Array::Dim_iter grid_dim = (grid->get_array()->dim_begin() + (map_i - grid->map_begin()));

    Array *map = dynamic_cast < Array * >((*map_i));
    if (!map)
        throw InternalErr(__FILE__, __LINE__, "Expected an Array");
    int start = max(map->dimension_start(map->dim_begin()), clause->get_start());
    int stop = min(map->dimension_stop(map->dim_begin()), clause->get_stop());

    if (start > stop) {
        ostringstream msg;
        msg
                << "The expressions passed to grid() do not result in an inclusive \n"
                << "subset of '" << clause->get_map_name()
                << "'. The map's values range " << "from "
                << clause->get_map_min_value() << " to "
                << clause->get_map_max_value() << ".";
        throw Error(malformed_expr,msg.str());
    }

    DBG(cerr << "Setting constraint on " << map->name() << "[" << start << ":" << stop << "]" << endl);

    // Stride is always one.
    map->add_constraint(map->dim_begin(), start, 1, stop);
    grid->get_array()->add_constraint(grid_dim, start, 1, stop);
}

void apply_grid_selection_expressions(Grid * grid, vector < GSEClause * >clauses)
{
    vector < GSEClause * >::iterator clause_i = clauses.begin();
    while (clause_i != clauses.end())
        apply_grid_selection_expr(grid, *clause_i++);

    grid->set_read_p(false);
}

} //namespace libdap