root/trunk/xpath_stack.d

/*
www.sourceforge.net/projects/tinyxpath
Copyright (c) 2002-2004 Yves Berquin (yvesb@users.sourceforge.net)

This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any
damages arising from the use of this software.

Permission is granted to anyone to use this software for any
purpose, including commercial applications, and to alter it and
redistribute it freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must
not claim that you wrote the original software. If you use this
software in a product, an acknowledgment in the product documentation
would be appreciated but is not required.

2. Altered source versions must be plainly marked as such, and
must not be misrepresented as being the original software.

3. This notice may not be removed or altered from any source
distribution.
*/

/**
    \file xpath_stack.h
    \author Yves Berquin
*/
module xpath.xpath_stack;
private {
import xpath.xpath_stream;
import xpath.xpath_expression;
import xpath.xpath_processor;
import xpath.node_set;
debug import std.stdio;


class result_and_next
{
private expression_result myE;
    public {
    /// Constructor
    this (expression_result er_in, result_and_next rnp_in_next) 
    {
        myE = er_in;
        rnp_next = rnp_in_next;
    }
    /// Return next element
    result_and_next rnp_get_next () 
    {
        return rnp_next;
    }
    }
    debug {
    void v_dump()
    {
        myE.v_dump();
    }
    }
    protected {
    /// Next element in the stack
    result_and_next rnp_next;
    } 
};

}
public
{



/// The XPath execution stack
/// \n All elements are result_and_next elements
class xpath_stack 
{
public : 
    debug 
    void v_dump ()
    {
        result_and_next rnp_ptr;

        writefln("--- stack start (%d elem) ---", u_size);
        rnp_ptr = rnp_first;
        while (rnp_ptr)
        {
            rnp_ptr.v_dump ();
            rnp_ptr = rnp_ptr.rnp_get_next ();
        }
        writefln("--- stack end ---");
    }


    this() { rnp_first = null; u_size = 0; }
    ~ this() { while (rnp_first) v_pop_one(); }
    void v_push (expression_result er_res)
    {
        result_and_next rnp_new;
    
        rnp_new = new result_and_next (er_res, rnp_first);
        rnp_first = rnp_new;
        u_size++;
    }

    void v_push_int (int i_elem, char[] cp_comment = "")
    {
        expression_result er_res = new expression_result;
        er_res . v_set_int (i_elem);
        if (cp_comment)
            er_res . v_set_comment (cp_comment);
        v_push (er_res);
    }

    void v_push_bool (bool o_in)
    {
        expression_result er_res = new expression_result;
        er_res . v_set_bool (o_in);
        v_push (er_res);
    }

    void v_push_string (char[] S_in)
    {
        expression_result er_res = new expression_result();
        er_res . v_set_string (S_in);
        v_push (er_res);
    }

    void v_push_double (double d_elem)
    {
        expression_result er_res = new expression_result;
        er_res . v_set_double (d_elem);
        v_push (er_res);
    }

    void v_push_node_set (node_set nsp_ptr)
    {
        expression_result er_res = new expression_result;
        er_res . v_set_node_set (nsp_ptr);
        v_push (er_res);
    }


    expression_result erp_top ()
    {
        if (! rnp_first)
            throw new execution_error (34);
        return rnp_first.myE;
    }

    int i_top_int ()
    {
        int i_res;
        
        i_res = erp_top () . i_get_int ();
        return i_res;   
    }


    void v_pop (uint u_nb = 1)
    {
        uint u_elem;
    
        for (u_elem = 0; u_elem < u_nb; u_elem++)
            v_pop_one ();
    }

    int i_pop_int ()
    {
        int i_res;
        
        i_res = erp_top().i_get_int ();
        v_pop ();
        return i_res;   
    }

    char[] S_pop_string ()
    {
        char[] S_res;
        
        S_res = erp_top () . S_get_string ();
        v_pop ();
        return S_res;   
    }

    bool o_pop_bool ()
    {
        bool o_res;
    
        o_res = erp_top ().o_get_bool ();
        v_pop ();
        return o_res;
    }
    node_set ns_pop_node_set ()
    {
        node_set ns_ret;
    
        ns_ret = erp_top () . nsp_get_node_set ();
        v_pop ();
        return ns_ret;
    }

    /// Return the stack's size
    uint u_get_size () {return u_size;}
    expression_result erp_previous (uint u_nb)
    {
        result_and_next rnp_current;
        uint u_prev;
    
        assert (u_nb <= u_size);
        rnp_current = rnp_first;
        for (u_prev = 0; u_prev < u_nb; u_prev++)
        {
            assert (rnp_current);
            rnp_current = rnp_current . rnp_get_next ();
        }
        return rnp_current.myE;
    }


protected :
    /// First element in the stack
    result_and_next rnp_first;
    /// Stack size
    uint u_size;
    void v_pop_one ()
    {
        result_and_next rnp_old;
    
        if (! u_size)
            throw new execution_error (35);
        if (! rnp_first)
            throw new execution_error (36);
        rnp_old = rnp_first;
        rnp_first = rnp_first.rnp_get_next;
        delete rnp_old;
        u_size--;
    }

} ;

}