logootsropes-crdt/lib/iteratorhelperidentifier.js

Provides several data structures to represent a text in a ropes-like structure and manipulating it

var Utils = require('utils-crdt');
var Iterator = require('./iterator');

IteratorHelperIdentifier = function (id1, id2) {
	this.id1 = id1;
	this.id2 = id2;
	this.nextOffset = null;
	this.result = null;
};

/**
 * Définition du type énuméré Result
 */
IteratorHelperIdentifier.Result = {
    B1AfterB2: 'B1AfterB2',
    B1BeforeB2: 'B1BeforeB2',
    B1InsideB2: 'B1InsideB2',
    B2InsideB1: 'B2InsideB1',
    B1ConcatB2: 'B1ConcatB2',
    B2ConcatB1: 'B2ConcatB1'
};

IteratorHelperIdentifier.prototype.compareBase = function () {
	var b1 = Utils.iterator(this.id1.base);
    var b2 = Utils.iterator(this.id2.base);

    while (b1.hasNext() && b2.hasNext()) {
        var i1 = b1.next();
        var i2 = b2.next();
        if (i1 > i2) {
            return this.Result.B1AfterB2;
        }
        else if (i1 < i2) {
            return this.Result.B1BeforeB2;
        }
    }
    if (b1.hasNext()) { //b2 is shorter than b1
        this.nextOffset = b1.next();
        if (this.nextOffset < this.id2.begin) {
            return this.Result.B1BeforeB2;
        }
        else if (this.nextOffset >= this.id2.end) {
            return this.Result.B1AfterB2;
        }
        else {
            return this.Result.B1InsideB2;
        }
    }
    else if (b2.hasNext()) { //b1 is shorter than b2
        this.nextOffset = b2.next();
        if (this.nextOffset < this.id1.begin) {
            return this.Result.B1AfterB2;
        }
        else if (this.nextOffset >= this.id1.end) {
            return this.Result.B1BeforeB2;
        }
        else {
            return this.Result.B2InsideB1;
        }
    }
    else { // both bases have the same size
        if (this.id1.end + 1 == this.id2.begin) {
            return this.Result.B1ConcatB2;
        }
        else if (this.id1.begin == this.id2.end + 1) {
            return this.Result.B2ConcatB1;
        }
        else if (this.id1.end < this.id2.begin) {
            return this.Result.B1BeforeB2;
        }
        else {
            return this.Result.B1AfterB2;
        }
    }
};

IteratorHelperIdentifier.prototype.computeResults = function() {
	if(this.result == null)
		this.result = this.compareBase();
	return this.result;
};

module.exports = IteratorHelperIdentifier;