Piper's Pit BBS/FTP: ibm 0040 - 0049/ibm0040-0049/ibm0040.tar/ibm0040/ZINC_6.ZIP/DOSSRC.ZIP/LIST.CPP

C/C++ Source or Header | 1991-06-01 | 5.0 KB | 210 lines

//    Zinc Interface Library - LIST.CPP
//    COPYRIGHT (C) 1990, 1991.  All Rights Reserved.
//    Zinc Software Incorporated.  Pleasant Grove, Utah  USA

#include "ui_gen.hpp"

// THIS COPYRIGHT NOTICE CANNOT BE REMOVED!
static char *_copyright = "\
COPYRIGHT (C) 1990, 1991. \
All Rights Reserved. \
Zinc Software Incorporated.  Pleasant Grove, Utah  USA.";

UI_ELEMENT *UI_LIST::Add(UI_ELEMENT *newElement)
{
    // See if it is a default insertion.
    if (!first || !compareFunction)
        return (UI_LIST::Add(0, newElement));

    // Get the beginning positions.
    int weight;
    UI_ELEMENT *element1, *element2;
    UI_ELEMENT *beginElement = first;
    UI_ELEMENT *endElement = last;

    // Shortcuts for elements in special orders.
    if ((*compareFunction)(endElement, newElement) <= 0)
        beginElement = endElement;
    else if ((*compareFunction)(beginElement, newElement) >= 0)
        beginElement = endElement = 0;

    // Find the proper element position.
    while (beginElement != endElement)
    {
        // Get the middle element - The order here is important!.
        element1 = beginElement;
        for (element2 = endElement; element1 != element2;
            element2 = element2->previous)
            if (element1->next != element2)
                element1 = element1->next;

        // Increment the proper element position.
        weight = (*compareFunction)(element1, newElement);
        if (weight > 0 && endElement != element1)
            endElement = element1;
        else if (weight < 0 && beginElement != element1)
            beginElement = element1;
        else
            beginElement = endElement = element1;
    }

    // Place the element in the sorted list.
    if (endElement)                    // Insert after endElement.
    {
        newElement->previous = endElement;
        newElement->next = endElement->next;
        if (newElement->next)
            newElement->next->previous = newElement;
        endElement->next = newElement;
        if (last == endElement)
            last = newElement;
    }
    else                            // Insert at beginning of the list.
    {
        newElement->previous = 0;
        newElement->next = first;
        first->previous = newElement;
        first = newElement;
    }

    // Return a pointer to the element.
    return (newElement);
}

UI_ELEMENT *UI_LIST::Add(UI_ELEMENT *element, UI_ELEMENT *newElement)
{
    // Add the element to the list.
    if (!first)
    {
        newElement->previous = newElement->next = 0;
        first = last = newElement;
    }
    else if (!element)
    {
        newElement->previous = last;
        newElement->next = 0;
        last->next = newElement;
        last = newElement;
    }
    else
    {
        newElement->previous = element->previous;
        newElement->next = element;
        if (!element->previous)
            first = newElement;
        else
            element->previous->next = newElement;
        element->previous = newElement;
    }

    // Return a pointer to the element.
    return (newElement);
}

int UI_LIST::Count()
{
    int count = 0;

    // Get the element index.
    for (UI_ELEMENT *element = first; element; element = element->next)
        count++;

    // Return the count.
    return (count);
}

UI_ELEMENT *UI_LIST::Subtract(UI_ELEMENT *element)
{
    // Make sure the element is in the list.
    UI_ELEMENT *tElement = element;
    while (tElement->previous)
        tElement = tElement->previous;
    if (tElement != first)
        return (element);

    // Delete the specified element from the list.
    if (element->previous)
        element->previous->next = element->next;
    else
        first = element->next;
    if (element->next)
        element->next->previous = element->previous;
    else
        last = element->previous;
    if (current == element)
        current = first;

    // Return the next element.
    return (element->next);
}

void UI_LIST::Destroy()
{
    UI_ELEMENT *tElement;

    // Delete all the elements in the list.
    for (UI_ELEMENT *element = first; element; )
    {
        tElement = element;
        element = element->next;
        delete tElement;
    }
    first = last = current = 0;
}

UI_ELEMENT *UI_LIST::Get(int index)
{
    // Get the list element.
    for (UI_ELEMENT *element = first; index && element; element = element->next)
        index--;

    // Return the element.
    return (element);
}

UI_ELEMENT *UI_LIST::Get(int (*findFunction)(void *element1, void *matchData), void *matchData)
{
    // Try to find the list element.
    for (UI_ELEMENT *element = first;
        element && (*findFunction)(element, matchData);
        element = element->next)
        ;

    // Return the element.
    return (element);
}

int UI_LIST::Index(const UI_ELEMENT *element)
{
    // Get the element index.
    int index = 0;
    for (UI_ELEMENT *tElement = first; tElement && tElement != element;
        tElement = tElement->next)
        index++;

    // Return the index.
    if (tElement)
        return (index);
    return (-1);
}

void UI_LIST::Sort()
{
    // Make sure there are elements in the list and a comparison routine.
    if (!first || !compareFunction)
        return;

    // Start the list with the first element.
    UI_ELEMENT *element;
    UI_ELEMENT *addElement = first;
    first = last = 0;

    // Sort the list of elements using the flat binary insertion.
    while (addElement)
    {
        element = addElement->next;
        UI_LIST::Add(addElement);
        addElement = element;
    }
}