Blame Operators.h

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// -*- mode: c++; c-basic-offset:4 -*-
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// This file is part of libdap, A C++ implementation of the OPeNDAP Data
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// Access Protocol.
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// Copyright (c) 2002,2003 OPeNDAP, Inc.
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// Author: James Gallagher <jgallagher@opendap.org>
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2.1 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
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//
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// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.
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// (c) COPYRIGHT URI/MIT 1999
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// Please read the full copyright statement in the file COPYRIGHT_URI.
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//
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// Authors:
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//      jhrg,jimg       James Gallagher <jgallagher@gso.uri.edu>
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// Templates for relational operations.
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//
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// jhrg 3/24/99
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#ifndef _operators_h
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#define _operators_h
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#include "GNURegex.h"  // GNU Regex class used for string =~ op.
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#include "ce_expr.tab.hh"
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namespace libdap {
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/** Compare two numerical types, both of which are either signed or unsigned.
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 This class is one implementation of the comparison policy used by
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 rops.
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 @see rops
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 @see USCmp
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 @see SUCmp */
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template<class T1, class T2>
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bool Cmp(int op, T1 v1, T2 v2)
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{
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	DBGN(cerr << __PRETTY_FUNCTION__ << v1 << " " << op << " " << v2 << endl);
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    switch (op) {
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        case SCAN_EQUAL:
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            return v1 == v2;
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        case SCAN_NOT_EQUAL:
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            return v1 != v2;
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        case SCAN_GREATER:
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            return v1 > v2;
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        case SCAN_GREATER_EQL:
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            return v1 >= v2;
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        case SCAN_LESS:
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            return v1 < v2;
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        case SCAN_LESS_EQL:
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            return v1 <= v2;
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        case SCAN_REGEXP:
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            throw Error(malformed_expr, "Regular expressions are supported for strings only.");
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        default:
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            throw Error(malformed_expr, "Unrecognized operator.");
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    }
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}
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template<class T>
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static inline unsigned long long dap_floor_zero(T i)
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{
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    return (unsigned long long) ((i < 0) ? 0 : i);
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}
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/** Compare two numerical types, the first one unsigned and the second
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 signed. If the signed argument is negative, zero is used in the
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 comparison. This class is one implementation of the comparison policy
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 used by rops.
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 @see rops
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 @see SUCmp
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 @see Cmp */
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template<class UT1, class T2>
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bool USCmp(int op, UT1 v1, T2 v2)
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{
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	DBGN(cerr << __PRETTY_FUNCTION__ << v1 << " " << op << " " << v2 << endl);
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    switch (op) {
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        case SCAN_EQUAL:
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            return v1 == dap_floor_zero<T2>(v2);
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        case SCAN_NOT_EQUAL:
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            return v1 != dap_floor_zero<T2>(v2);
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        case SCAN_GREATER:
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            return v1 > dap_floor_zero<T2>(v2);
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        case SCAN_GREATER_EQL:
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            return v1 >= dap_floor_zero<T2>(v2);
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        case SCAN_LESS:
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            return v1 < dap_floor_zero<T2>(v2);
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        case SCAN_LESS_EQL:
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            return v1 <= dap_floor_zero<T2>(v2);
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        case SCAN_REGEXP:
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            throw Error(malformed_expr, "Regular expressions are supported for strings only.");
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        default:
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            throw Error(malformed_expr, "Unrecognized operator.");
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    }
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}
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/** Compare two numerical types, the first one signed and the second
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 unsigned. If the signed argument is negative, zero is used in the
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 comparison. This class is one implementation of the comparison policy
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 used by rops. This class is here to make writing the Byte::ops, ...
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 member functions simpler. It is not necessary since the functions could
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 twidle the order of arguments to rops and use <tt>USCmp</tt>. Having
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 this class make Byte:ops, ... simpler to read and write.
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 @see Byte::ops
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 @see USCmp
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 @see Cmp
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 @see ops */
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template<class T1, class UT2>
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bool SUCmp(int op, T1 v1, UT2 v2)
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{
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	DBGN(cerr << __PRETTY_FUNCTION__ << v1 << " " << op << " " << v2 << endl);
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    switch (op) {
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        case SCAN_EQUAL:
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            return dap_floor_zero<T1>(v1) == v2;
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        case SCAN_NOT_EQUAL:
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            return dap_floor_zero<T1>(v1) != v2;
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        case SCAN_GREATER:
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            return dap_floor_zero<T1>(v1) > v2;
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        case SCAN_GREATER_EQL:
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            return dap_floor_zero<T1>(v1) >= v2;
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        case SCAN_LESS:
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            return dap_floor_zero<T1>(v1) < v2;
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        case SCAN_LESS_EQL:
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            return dap_floor_zero<T1>(v1) <= v2;
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        case SCAN_REGEXP:
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            throw Error(malformed_expr, "Regular expressions are supported for strings only.");
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        default:
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            throw Error(malformed_expr, "Unrecognized operator.");
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    }
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}
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/** Compare two string types.
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 This class is one implementation of the comparison policy used by
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 rops.
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 @see rops */
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template<class T1, class T2>
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bool StrCmp(int op, T1 v1, T2 v2)
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{
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    switch (op) {
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        case SCAN_EQUAL:
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            return v1 == v2;
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        case SCAN_NOT_EQUAL:
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            return v1 != v2;
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        case SCAN_GREATER:
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            return v1 > v2;
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        case SCAN_GREATER_EQL:
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            return v1 >= v2;
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        case SCAN_LESS:
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            return v1 < v2;
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        case SCAN_LESS_EQL:
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            return v1 <= v2;
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        case SCAN_REGEXP: {
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            Regex r(v2.c_str());
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            return r.match(v1.c_str(), v1.length()) > 0;
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        }
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        default:
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            throw Error(malformed_expr, "Unrecognized operator.");
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    }
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}
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} // namespace libdap
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#endif // _operators_h