D4ConstraintEvaluator.h

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// -*- 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: James Gallagher <jgallagher@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.
 
#ifndef D4CEDRIVER_H_
#define D4CEDRIVER_H_
 
#include <stack>
#include <string>
#include <vector>
 
#include "Array.h"
 
namespace libdap {
 
class location;
class DMR;
class BaseType;
class Array;
class D4Dimension;
class D4FilterClause;
class D4FilterClauseList;

class D4ConstraintEvaluator {
    struct index {
        // start and stride are simple numbers; stop is either the stopping index or
        // if rest is true, is ignored and the subset runs to the end of the dimension
        int64_t start = 0;
        int64_t stride = 0;
        int64_t stop = 0;
        // true if the slice indicates it does not contain a specific 'stop' value but
        // goes to the end, whatever that value is.
        bool rest = false;
        // An empty slice ([]) means either the entire dimension or apply the shared
        // dimension slice, depending on whether the corresponding shared dimension has
        // been sliced.
        bool empty = false;
        // When a slice is applied to an Array with Maps, we need to know the name of
        // each dimension. These names are then used to apply the slice to each of the
        // Maps (Maps may have fewer dimensions than the Array, but the idea that a
        // Map is a simple vector doesn't hold for DAP4, so the mapping between a slice's
        // indexes and the set of Maps can be complex - use the names to make sure
        // all cases are covered. The value of this field may be empty.
        std::string dim_name;
 
        // Added because the parser code needs it. Our code does not use this. jhrg 11/26/13
        index() = default;
        index(int64_t i, int64_t s, int64_t e, bool r, bool em, std::string n)
            : start(i), stride(s), stop(e), rest(r), empty(em), dim_name{std::move(n)} {}
    };
 
    static index make_index() { return {0, 1, 0, true /*rest*/, true /*empty*/, ""}; }
 
    static index make_index(const std::string &is);
 
    static index make_index(const std::string &i, const std::string &s, const std::string &e);
    static index make_index(const std::string &i, int64_t s, const std::string &e);
 
    static index make_index(const std::string &i, const std::string &s);
    static index make_index(const std::string &i, int64_t s);
 
    bool d_trace_scanning = false;
    bool d_trace_parsing = false;
    bool d_result = false;
    std::string d_expr;
 
    DMR *d_dmr = nullptr;
 
    std::vector<index> d_indexes;
 
    std::stack<BaseType *> d_basetype_stack;
 
    // d_expr should be set by parse! Its value is used by the parser right before
    // the actual parsing operation starts. jhrg 11/26/13
    std::string *expression() { return &d_expr; }
 
    void search_for_and_mark_arrays(BaseType *btp);
    BaseType *mark_variable(BaseType *btp);
    BaseType *mark_array_variable(BaseType *btp);
    static void use_explicit_projection(Array *a, const Array::Dim_iter &dim_iter,
                                        const D4ConstraintEvaluator::index &index);
 
    D4Dimension *slice_dimension(const std::string &id, const index &i);
 
    void push_index(const index &i) { d_indexes.push_back(i); }
 
    void push_basetype(BaseType *btp) { d_basetype_stack.push(btp); }
    BaseType *top_basetype() const { return d_basetype_stack.empty() ? nullptr : d_basetype_stack.top(); }
    // throw on pop with an empty stack?
    void pop_basetype() { d_basetype_stack.pop(); }
 
    [[noreturn]] static void throw_not_found(const std::string &id, const std::string &ident);
    [[noreturn]] static void throw_not_array(const std::string &id, const std::string &ident);
 
    // Build FilterClauseList for filter clauses for a Sequence
    void add_filter_clause(const std::string &op, const std::string &arg1, const std::string &arg2) const;
 
    static std::string &remove_quotes(std::string &src);
 
    friend class D4CEParser;
    friend class D4ConstraintEvaluatorTest;
 
public:
    D4ConstraintEvaluator() = default;
    explicit D4ConstraintEvaluator(DMR *dmr) : d_dmr(dmr) {}
 
    virtual ~D4ConstraintEvaluator() = default;
 
    bool parse(const std::string &expr);
 
    bool trace_scanning() const { return d_trace_scanning; }
    void set_trace_scanning(bool ts) { d_trace_scanning = ts; }
 
    bool trace_parsing() const { return d_trace_parsing; }
    void set_trace_parsing(bool tp) { d_trace_parsing = tp; }
 
    bool result() const { return d_result; }
    void set_result(bool r) { d_result = r; }
 
    DMR *dmr() const { return d_dmr; }
    void set_dmr(DMR *dmr) { d_dmr = dmr; }
 
    [[noreturn]] static void error(const libdap::location &l, const std::string &m);
};
 
} /* namespace libdap */
#endif /* D4CEDRIVER_H_ */