D4FunctionEvaluator.cc

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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) 2014 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.
 
#include <cerrno>
#include <cstdlib>
 
#include <algorithm>
#include <iterator>
#include <list>
#include <memory>
#include <sstream>
#include <string>
 
#include "D4FunctionEvaluator.h"
#include "D4FunctionScanner.h"
#include "d4_function_parser.tab.hh"
 
#include "Array.h"
#include "D4Enum.h"
#include "D4Group.h"
#include "DMR.h"
 
#include "debug.h"
#include "escaping.h"
#include "util.h"
 
namespace libdap {

bool D4FunctionEvaluator::parse(const std::string &expr) {
    d_expr = expr; // set for error messages. See the %initial-action section of .yy
 
    std::istringstream iss(expr);
    D4FunctionScanner scanner(iss);
    D4FunctionParser parser(scanner, *this /* driver */);
 
    if (trace_parsing()) {
        parser.set_debug_level(1);
        parser.set_debug_stream(std::cerr);
    }
 
    return parser.parse() == 0;
}

void D4FunctionEvaluator::eval(DMR *function_result) {
    if (!d_result)
        throw InternalErr(__FILE__, __LINE__, "Must parse() the function expression before calling eval()");
 
    D4Group *root = function_result->root(); // Load everything in the root group
    for (auto result : *d_result) {
        // Copy the BaseTypes; this means all the function results can
        // be deleted, which addresses the memory leak issue with function
        // results. This should also copy the D4Dimensions. jhrg 3/17/14
        root->add_var(result->value(*d_dmr));
    }
 
    delete d_result; // The parser/function allocates the BaseType*s that hold the results.
    d_result = nullptr;
 
    // Variables can use Dimensions and Enumerations, so those need to be copied
    // from the source dataset to the result. NB: The variables that refer to these
    // use weak pointers.
 
    // Make a set of D4Dimensions. For each variable in 'function_result', look
    // for its dimensions in 'dataset' (by name) and add a pointer to those to the
    // set. Then copy all the stuff in the set into the root group of 'function_
    // result.'
    list<D4Dimension *> dim_set;
 
    for (auto i = root->var_begin(), ie = root->var_end(); i != ie; ++i) {
        if ((*i)->is_vector_type()) {
            auto a = static_cast<Array *>(*i);
            for (auto d = a->dim_begin(), de = a->dim_end(); d != de; ++d) {
                // Only add Dimensions that are not already present; share dims are not repeated. jhrg 2/7/18
                D4Dimension *d4_dim = a->dimension_D4dim(d);
                if (d4_dim) {
                    bool found = (std::find(dim_set.begin(), dim_set.end(), d4_dim) != dim_set.end());
                    if (!found)
                        dim_set.push_back(a->dimension_D4dim(d));
                }
            }
        }
    }
 
    // Copy the D4Dimensions and EnumDefs because this all goes in a new DMR - we don't
    // want to share those across DMRs because the DMRs delete those (so sharing htem
    // across DMRs would lead to dangling pointers.
    for (auto dim : dim_set) {
        root->dims()->add_dim(dim);
    }
 
    // Now let's do the enumerations....
    list<D4EnumDef *> enum_def_set;
    for (auto i = root->var_begin(), ie = root->var_end(); i != ie; ++i) {
        if ((*i)->type() == dods_enum_c) {
            enum_def_set.push_back(static_cast<D4Enum *>(*i)->enumeration());
        }
    }
 
    for (auto enum_def : enum_def_set) {
        root->enum_defs()->add_enum(enum_def);
    }
}
 
// libdap contains functions (in parser-util.cc) that test if a string
// can be converted to an int32, e.g., but I used a more streamlined
// approach here. 3/13/14 jhrg
D4RValue *D4FunctionEvaluator::build_rvalue(const std::string &id) {
    BaseType *btp = nullptr;
 
    // Look for the id in the dataset first
    if (top_basetype()) {
        btp = top_basetype()->var(id);
    } else {
        btp = dmr()->root()->find_var(id);
    }
 
    if (btp)
        return new D4RValue(btp);
 
    // If the id is not a variable, try to turn it into a constant,
    // otherwise, it's an error.
    char *end_ptr = nullptr;
 
    errno = 0;
    long long ll_val = strtoll(id.c_str(), &end_ptr, 0);
    if (*end_ptr == '\0' && errno == 0)
        return new D4RValue(ll_val);
 
    // Test for unsigned after signed since strtoull() accepts a minus sign
    // (and will return a huge number if that's the case). jhrg 3/13/14
    errno = 0;
    unsigned long long ull_val = strtoull(id.c_str(), &end_ptr, 0);
    if (*end_ptr == '\0' && errno == 0)
        return new D4RValue(ull_val);
 
    errno = 0;
    double d_val = strtod(id.c_str(), &end_ptr);
    if (*end_ptr == '\0' && errno == 0)
        return new D4RValue(d_val);
 
    // To be a valid string, the id must be quoted (using double quotes)
    if (is_quoted(id))
        return new D4RValue(www2id(id));
 
    // if it's none of these, return null
    return nullptr;
}
 
// TODO Make the arg_list a unique_ptr through out. jhrg 2/22/24
template <typename T> vector<T> *D4FunctionEvaluator::init_arg_list(T val) {
    auto arg_list = make_unique<vector<T>>();
    if (get_arg_length_hint() > 0)
        arg_list->reserve(get_arg_length_hint());
 
    arg_list->push_back(val);
 
    return arg_list.release();
}
 
// Force an instantiation so this can be called from within the d4_function.yy
// parser.
template std::vector<dods_byte> *D4FunctionEvaluator::init_arg_list(dods_byte val);
template std::vector<dods_int8> *D4FunctionEvaluator::init_arg_list(dods_int8 val);
template std::vector<dods_uint16> *D4FunctionEvaluator::init_arg_list(dods_uint16 val);
template std::vector<dods_int16> *D4FunctionEvaluator::init_arg_list(dods_int16 val);
template std::vector<dods_uint32> *D4FunctionEvaluator::init_arg_list(dods_uint32 val);
template std::vector<dods_int32> *D4FunctionEvaluator::init_arg_list(dods_int32 val);
template std::vector<dods_uint64> *D4FunctionEvaluator::init_arg_list(dods_uint64 val);
template std::vector<dods_int64> *D4FunctionEvaluator::init_arg_list(dods_int64 val);
template std::vector<dods_float32> *D4FunctionEvaluator::init_arg_list(dods_float32 val);
template std::vector<dods_float64> *D4FunctionEvaluator::init_arg_list(dods_float64 val);
 
// This method is called from the parser (see d4_function_parser.yy, down in the code
// section). This will be called during the call to D4FunctionParser::parse(), that
// is inside D4FunctionEvaluator::parse(...)
[[noreturn]] void D4FunctionEvaluator::error(const libdap::location &l, const std::string &m) {
    ostringstream oss;
    oss << l << ": " << m << ends;
    throw Error(malformed_expr, oss.str());
}
 
} /* namespace libdap */