range-list.js

if (require) {
    var stampit = require('stampit');
}

var RangeList = stampit()
    .refs({
        // max - maximal size of a single interval
    })
    .init(function () {

        /*
         * Entries look like { start: x, end: y, items: [] }
         */

        var list = [];

        var init = function () {
        
        
        }.bind(this);

        var shrink = function () {

            if (list.length === 1 ) {
                optimize();
                return this;
            }

            var next, j = 0;

            while (j < list.length - 1) {

                cur = list[j];
                next = list[j + 1];

                if (cur.end >= next.start - 1 ) {

                    cur.end = Math.max(cur.end, next.end);

                    list.splice(j + 1, 1);

                    continue;

                }

                j += 1;

            }

            optimize();

        }.bind(this);

        /**
         * @param {number} start - Index of the intervals start.
         * @param {number} end - Index of the intervals end.
         **/
        this.merge = function (start, end) {

            if (end <= start) {
                return this;
            }

            if (list.length === 0) {

                list.push({ start: start, end: end });
                return this;

            }

            for (var i in list) {

                cur = list[i];

                // neuer start ist größer als element ende
                // => füge am ende der liste ein

                if (cur.start > end) {

                    list.splice(i, 0, { start: start, end: end });

                    shrink();

                    return this;

                }

                if (cur.start >= start && cur.end > start) {

                    if (cur.end < end) {

                        cur.start   = start;
                        cur.end     = start + end;

                        shrink();

                        return this;

                    }

                    if (cur.end >= end) {

                        cur.start   = start;
                        cur.end     = cur.end;

                        shrink();

                        return this;

                    }

                }

                if (cur.start < start && cur.end > start) {

                    if (cur.end >= end) {

                        shrink();

                        return this;      

                    }

                    if (cur.end < end) {

                        cur.end     = end;

                        shrink();

                        return this;

                    }

                }

            }

            list.push({ start: start, end: end });

            shrink();

            return this;

        };

        var optimize = function () {

            if (!this.max) {
                return;
            }

            var l = [], start, end;

            for (var i = 0; i < list.length; i += 1) {

                if (list[i].end - list[i].start > this.max) {

                    list.splice(i + 1, 0, { start: list[i].start + this.max, end: list[i].end });

                    list[i].end = list[i].start + this.max;

                }

            }

        }.bind(this);

        this.getList = function () {

            return list;

        };

        init();

    });

if (module) {
    module.exports = RangeList;
}