Path.cpp

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/*
 * This file is part of the DUDS project. It is subject to the BSD-style
 * license terms in the LICENSE file found in the top-level directory of this
 * distribution and at https://github.com/jjackowski/duds/blob/master/LICENSE.
 * No part of DUDS, including this file, may be copied, modified, propagated,
 * or distributed except according to the terms contained in the LICENSE file.
 *
 * Copyright (C) 2020  Jeff Jackowski
 */
#include <duds/ui/Path.hpp>

namespace duds { namespace ui {

Path::Path(const PageSptr &first) {
    pages.push_back(first);
    spot = 0;
}

void Path::push(const PageSptr &page) {
    // is the current page not the last page on the stack?
    if (pages.size() > (spot + 1)) {
        // remove pages past the new current page
        pages.resize(spot + 2);
        // place the new page after the current
        pages[++spot] = page;
    } else {
        // add to the end
        pages.emplace_back(page);
        ++spot;
    }
}

void Path::push(PageSptr &&page) {
    // is the current page not the last page on the stack?
    if (pages.size() > (spot + 1)) {
        // remove pages past the new current page
        pages.resize(spot + 2);
        // place the new page after the current
        pages[++spot] = std::move(page);
    } else {
        // add to the end
        pages.emplace_back(std::move(page));
        ++spot;
    }
}

bool Path::move(int steps) {
    // no change?
    if (!steps) {
        return false;
    }
    int ospot = spot;
    // calcuate the new current page spot
    int nspot = spot + steps;
    // limit it to the range of the stack
    if (steps > 0) {
        spot = std::min((PageStack::size_type)nspot, pages.size() - 1);
    } else {
        spot = std::max(nspot, 0);
    }
    // compare current just set spot with the old one
    return spot != ospot;
}

void Path::clear() {
    pages.clear();
    spot = -1;
}

void Path::clearPastCurrent() {
    pages.resize(spot + 1);
}

} }