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diffsync.js
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var diffsync = (typeof(module) != 'undefined') ? module.exports : {}
diffsync.version = 1039
diffsync.port = 60607
// var client = diffsync.create_client({
// ws_url : 'ws://invisible.college:' + diffsync.port,
// channel : 'the_cool_room',
// get_text : function () {
// return current_text_displayed_to_user
// },
// get_range : function () {
// return [selection_start, selection_end]
// },
// on_text : function (text, range) {
// current_text_displayed_to_user = text
// set_selection(range[0], range[1])
// },
// on_ranges : function (peer_ranges) {
//. for (peer in peer_ranges) {
// set_peer_selection(peer_ranges[peer][0], peer_ranges[peer][1])
// }
// }
// })
//
// client.on_change() <-- call this when the user changes the text or cursor/selection position
//
diffsync.create_client = function (options) {
var self = {}
self.on_change = null
self.on_window_closing = null
self.get_channels = null
options.network_broke = options.network_broke || function () {}
var on_channels = null
var uid = guid()
var minigit = diffsync.create_minigit()
var unacknowledged_commits = {}
var prev_range = [-1, -1]
var peer_ranges = {}
window.addEventListener('beforeunload', function () {
if (self.on_window_closing) self.on_window_closing()
})
var connected = false
function reconnect() {
connected = false
console.log('connecting...')
var ws = new WebSocket(options.ws_url)
function send(o) {
o.v = diffsync.version
o.uid = uid
o.channel = options.channel
try {
ws.send(JSON.stringify(o))
} catch (e) {}
}
self.on_window_closing = function () {
send({ close : true })
}
self.get_channels = function (cb) {
on_channels = cb
send({ get_channels : true })
}
ws.onopen = function () {
connected = true
send({ join : true })
options.network_broke(false)
// on_pong()
}
// var pong_timer = null
// function on_pong() {
// clearTimeout(pong_timer)
// setTimeout(function () {
// send({ ping : true })
// pong_timer = setTimeout(function () {
// console.log('no pong came!!')
// if (ws) {
// ws = null
// options.network_broke(true)
// reconnect()
// }
// }, 4000)
// }, 3000)
// }
ws.onclose = function () {
console.log('connection closed...')
options.network_broke(true)
if (ws) {
ws = null
setTimeout(reconnect, 3000)
}
}
var sent_unacknowledged_commits = false
function adjust_range(range, patch) {
return map_array(range, function (x) {
each(patch, function (p) {
if (p[0] < x) {
if (p[0] + p[1] <= x) {
x += -p[1] + p[2].length
} else {
x = p[0] + p[2].length
}
} else return false
})
return x
})
}
ws.onmessage = function (event) {
if (!ws) { return }
var o = JSON.parse(event.data)
// if (o.pong) { return on_pong() }
console.log('message: ' + event.data)
if (o.channels) {
if (on_channels) on_channels(o.channels)
}
if (o.commits) {
// self.on_change()
minigit.merge(o.commits)
var patch = get_diff_patch(options.get_text(), minigit.cache)
each(peer_ranges, function (range, peer) {
peer_ranges[peer] = adjust_range(range, patch)
})
prev_range = adjust_range(options.get_range(), patch)
options.on_text(minigit.cache, prev_range)
if (o.welcome) {
each(extend(o.commits, minigit.get_ancestors(o.commits)), function (_, id) {
delete unacknowledged_commits[id]
})
if (Object.keys(unacknowledged_commits).length > 0) {
send({ commits : unacknowledged_commits })
}
sent_unacknowledged_commits = true
}
send({ leaves : minigit.leaves })
}
if (o.may_delete) {
each(o.may_delete, function (_, id) {
delete unacknowledged_commits[id]
minigit.remove(id)
})
}
if (o.range) {
peer_ranges[o.uid] = o.range
}
if (o.close) {
delete peer_ranges[o.uid]
}
if ((o.range || o.close || o.commits) && options.on_ranges) {
options.on_ranges(peer_ranges)
}
}
self.on_change = function () {
// if (!connected) { return }
var old_cache = minigit.cache
var cs = minigit.commit(options.get_text())
if (cs) {
extend(unacknowledged_commits, cs)
var patch = null
var c = cs[Object.keys(cs)[0]]
var parents = Object.keys(c.from_parents)
if (parents.length == 1)
patch = c.from_parents[parents[0]]
else
patch = get_diff_patch(old_cache, minigit.cache)
each(peer_ranges, function (range, peer) {
peer_ranges[peer] = adjust_range(range, patch)
})
if (options.on_ranges) options.on_ranges(peer_ranges)
}
if (!sent_unacknowledged_commits) { return }
var range = options.get_range()
var range_changed = (range[0] != prev_range[0]) || (range[1] != prev_range[1])
prev_range = range
var msg = {}
if (cs) msg.commits = cs
if (range_changed) msg.range = range
if (cs || range_changed) send(msg)
}
}
reconnect()
return self
}
// options is an object like this: {
// wss : a websocket server from the 'ws' module,
// initial_data : {
// 'some_channel_name' : {
// commits : {
// 'asdfasdf' : {
// to_parents : {},
// from_parents : {},
// text : 'hello'
// }
// },
// members : {
// 'lkjlkjlkj' : {
// do_not_delete : {
// 'asdfasdf' : true
// }
// }
// }
// }
// },
// on_change : function (changes) {
// changes contains commits and members that changed,
// and looks like: {
// channel : 'some_channel_name',
// commits : {...},
// members : {...}
// }
// }
// }
//
diffsync.create_server = function (options) {
var self = {}
self.channels = {}
function new_channel(name) {
return self.channels[name] = {
name : name,
minigit : diffsync.create_minigit(),
members : {}
}
}
function get_channel(name) {
return self.channels[name] || new_channel(name)
}
var users_to_sockets = {}
if (options.initial_data) {
each(options.initial_data, function (data, channel) {
var c = get_channel(channel)
c.minigit.merge(data.commits)
extend(c.members, data.members)
})
}
options.wss.on('connection', function connection(ws) {
console.log('new connection')
var uid = null
var channel_name = null
function myClose() {
if (!uid) { return }
delete users_to_sockets[uid]
each(users_to_sockets, function (_ws, _uid) {
try {
_ws.send(JSON.stringify({
v : diffsync.version,
uid : uid,
channel : channel_name,
close : true
}))
} catch (e) {}
})
}
ws.on('close', myClose)
ws.on('error', myClose)
ws.on('message', function (message) {
var o = JSON.parse(message)
if (o.v != diffsync.version) { return }
if (o.ping) { return try_send(ws, JSON.stringify({ pong : true })) }
console.log('message: ' + message)
uid = o.uid
var channel = get_channel(o.channel)
channel_name = channel.name
users_to_sockets[uid] = ws
var changes = { channel : channel.name, commits : {}, members : {} }
if (!channel.members[uid]) channel.members[uid] = { do_not_delete : {} }
changes.members[uid] = channel.members[uid]
function try_send(ws, message) {
try {
ws.send(message)
} catch (e) { return false }
return true
}
function send_to_all_but_me(message) {
each(channel.members, function (_, them) {
if (them != uid) {
try_send(users_to_sockets[them], message)
}
})
}
if (o.get_channels) {
try_send(ws, JSON.stringify({ channels : Object.keys(self.channels) }))
}
if (o.join) {
try_send(ws, JSON.stringify({ commits : channel.minigit.commits, welcome : true }))
}
if (o.commits) {
var new_commits = {}
each(o.commits, function (c, id) {
if (!channel.minigit.commits[id]) {
new_commits[id] = c
changes.commits[id] = c
}
})
channel.minigit.merge(new_commits)
var new_message = {
channel : channel.name,
commits : new_commits
}
if (o.range) {
new_message.uid = o.uid
new_message.range = o.range
}
new_message = JSON.stringify(new_message)
leaves = channel.minigit.get_leaves(new_commits)
var now = Date.now()
each(channel.members, function (m, them) {
if (them != uid) {
if (try_send(users_to_sockets[them], new_message)) {
extend(m.do_not_delete, leaves)
changes.members[them] = m
}
}
})
if (!o.leaves) o.leaves = channel.minigit.get_leaves(o.commits)
} else if (o.range) {
send_to_all_but_me(message)
}
if (o.leaves) {
extend(channel.members[uid].do_not_delete, o.leaves)
each(channel.minigit.get_ancestors(o.leaves), function (_, id) {
delete channel.members[uid].do_not_delete[id]
})
var necessary = {}
each(channel.members, function (m) {
extend(necessary, m.do_not_delete)
})
var affected = channel.minigit.remove_unnecessary(necessary)
extend(changes.commits, affected)
var new_message = {
channel : channel.name,
may_delete : {}
}
each(affected, function (c, id) {
if (c.delete_me) {
new_message.may_delete[id] = true
}
})
if (Object.keys(new_message.may_delete).length > 0) {
new_message = JSON.stringify(new_message)
each(channel.members, function (m, them) {
try_send(users_to_sockets[them], new_message)
})
}
}
if (o.close) {
channel.members[uid].delete_me = true
delete channel.members[uid]
}
if (options.on_change) options.on_change(changes)
})
})
return self
}
///////////////
diffsync.create_minigit = function () {
var self = {
commits : {},
to_children : {},
commit_cache : {},
leaves : {},
cache : ''
}
self.remove_unnecessary = function (spare_us) {
var affected = {}
while (true) {
var found = false
each(self.commits, function (c, id) {
if (spare_us[id]) { return }
var aff = self.remove(id)
if (aff) {
extend(affected, aff)
found = true
}
})
if (!found) break
}
return affected
}
self.remove = function (id) {
var keys = Object.keys(self.to_children[id])
if (keys.length == 1) {
var affected = {}
var being_removed = self.commits[id]
var c_id = keys[0]
var c = self.commits[c_id]
self.get_text(c_id)
each(being_removed.to_parents, function (_, id) {
self.get_text(id)
})
delete self.commits[id]
delete self.commit_cache[id]
delete c.to_parents[id]
delete c.from_parents[id]
being_removed.delete_me = true
affected[id] = being_removed
each(being_removed.to_parents, function (_, id) {
var x = get_diff_patch_2(self.get_text(c_id), self.get_text(id))
c.to_parents[id] = x[0]
c.from_parents[id] = x[1]
})
if (Object.keys(c.to_parents).length == 0) {
c.text = self.get_text(c_id)
}
affected[c_id] = c
self.calc_children()
return affected
}
}
self.commit = function (s) {
if (s == self.cache) { return }
var c = {
to_parents : {},
from_parents : {}
}
if (Object.keys(self.leaves).length == 0) {
c.text = s
} else {
each(self.leaves, function (_, leaf) {
var x = get_diff_patch_2(s, self.get_text(leaf))
c.to_parents[leaf] = x[0]
c.from_parents[leaf] = x[1]
})
}
var id = guid()
self.commits[id] = c
self.calc_children()
self.leaves = {}
self.leaves[id] = true
self.commit_cache[id] = s
self.cache = s
self.purge_cache()
var cs = {}
cs[id] = c
return cs
}
self.merge = function (cs) {
each(cs, function (c, id) {
if (!self.commits[id]) {
self.commits[id] = c
} else {
if (c.text) self.commits[id].text = c.text
extend(self.commits[id].to_parents, c.to_parents)
extend(self.commits[id].from_parents, c.from_parents)
}
})
self.calc_children()
self.leaves = self.get_leaves()
self.cache = self.rec_merge(self.leaves)
self.purge_cache()
return self.cache
}
self.calc_children = function () {
self.to_children = {}
each(self.commits, function (c, id) {
self.to_children[id] = {}
})
each(self.commits, function (c, id) {
each(c.from_parents, function (d, p_id) {
self.to_children[p_id][id] = d
})
})
}
self.purge_cache = function () {
each(self.commits, function (c, id) {
if (Object.keys(c.to_parents).length > 0 && !self.leaves[id]) {
delete self.commit_cache[id]
}
})
}
self.get_text = function (id) {
if (self.commit_cache[id] != null) return self.commit_cache[id]
var frontier = [id]
var back_pointers = {}
back_pointers[id] = id
while (true) {
var next = frontier.shift()
if (!next) { throw 'data structure corrupted' }
var c_id = next
var c = self.commits[c_id]
var text = (c.text != null) ? c.text : self.commit_cache[c_id]
if (text != null) {
var snowball = text
while (true) {
if (next == id) {
return self.commit_cache[id] = snowball
}
next = back_pointers[next]
snowball = apply_diff_patch(snowball, c.to_parents[next] || self.to_children[c_id][next])
c_id = next
c = self.commits[c_id]
}
}
each(c.to_parents, function (_, id) {
if (!back_pointers[id]) {
back_pointers[id] = next
frontier.push(id)
}
})
each(self.to_children[c_id], function (_, id) {
if (!back_pointers[id]) {
back_pointers[id] = next
frontier.push(id)
}
})
}
}
self.rec_merge = function (these) {
these = Object.keys(these)
if (these.length == 0) { return '' }
var r = self.get_text(these[0])
if (these.length == 1) { return r }
var r_ancestors = self.get_ancestors(these[0])
for (var i = 1; i < these.length; i++) {
var i_ancestors = self.get_ancestors(these[i])
var o = self.rec_merge(self.get_leaves(intersection(r_ancestors, i_ancestors)))
r = apply_diff_patch(o, get_merged_diff_patch(r, self.get_text(these[i]), o))
extend(r_ancestors, i_ancestors)
}
return r
}
self.get_leaves = function (commits) {
if (!commits) commits = self.commits
var leaves = {}
each(commits, function (_, id) { leaves[id] = true })
each(commits, function (c) {
each(c.to_parents, function (_, p) {
delete leaves[p]
})
})
return leaves
}
self.get_ancestors = function (id_or_set) {
var frontier = null
if (typeof(id_or_set) == 'object') {
frontier = Object.keys(id_or_set)
} else {
frontier = [id_or_set]
}
var ancestors = {}
while (frontier.length > 0) {
var next = frontier.shift()
each(self.commits[next].to_parents, function (_, p) {
if (!ancestors[p]) {
ancestors[p] = self.commits[p]
frontier.push(p)
}
})
}
return ancestors
}
return self
}
///////////////
function guid() {
var x = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
var s = []
for (var i = 0; i < 15; i++) {
s.push(x[Math.floor(Math.random() * x.length)])
}
return s.join('')
}
function each(o, cb) {
if (o instanceof Array) {
for (var i = 0; i < o.length; i++) {
if (cb(o[i], i, o) == false)
return false
}
} else {
for (var k in o) {
if (o.hasOwnProperty(k)) {
if (cb(o[k], k, o) == false)
return false
}
}
}
return true
}
function map_array(a, f) {
var b = []
each(a, function (v, k) { b[k] = f(v) })
return b
}
function extend(a, b) {
each(b, function (x, key) { a[key] = x })
return a
}
function intersection(a, b) {
var common = {}
each(a, function (_, x) {
if (b[x]) {
common[x] = a[x]
}
})
return common
}
///////////////
var DIFF_DELETE = -1;
var DIFF_INSERT = 1;
var DIFF_EQUAL = 0;
function get_merged_diff_patch(a, b, o) {
var a_diff = get_diff_patch(o, a)
var b_diff = get_diff_patch(o, b)
var ds = []
var prev_d = null
while (a_diff.length > 0 || b_diff.length > 0) {
var d = a_diff.length == 0 ?
b_diff.shift() :
b_diff.length == 0 ?
a_diff.shift() :
a_diff[0][0] < b_diff[0][0] ?
a_diff.shift() :
a_diff[0][0] > b_diff[0][0] ?
b_diff.shift() :
a_diff[0][2] < b_diff[0][2] ?
a_diff.shift() :
b_diff.shift()
if (prev_d && d[0] < prev_d[0] + prev_d[1]) {
if (d[0] + d[1] > prev_d[0] + prev_d[1]) {
prev_d[1] = d[0] + d[1] - prev_d[0]
}
prev_d[2] += d[2]
} else {
ds.push(d)
prev_d = d
}
}
return ds
}
function apply_diff_patch(s, diff) {
var offset = 0
for (var i = 0; i < diff.length; i++) {
var d = diff[i]
s = s.slice(0, d[0] + offset) + d[2] + s.slice(d[0] + offset + d[1])
offset += d[2].length - d[1]
}
return s
}
function diff_convert_to_my_format(d, factor) {
if (factor === undefined) factor = 1
var x = []
var ii = 0
for (var i = 0; i < d.length; i++) {
var dd = d[i]
if (dd[0] == DIFF_EQUAL) {
ii += dd[1].length
continue
}
var xx = [ii, 0, '']
if (dd[0] == DIFF_INSERT * factor) {
xx[2] = dd[1]
} else if (dd[0] == DIFF_DELETE * factor) {
xx[1] = dd[1].length
ii += xx[1]
}
if (i + 1 < d.length) {
dd = d[i + 1]
if (dd[0] != DIFF_EQUAL) {
if (dd[0] == DIFF_INSERT * factor) {
xx[2] = dd[1]
} else if (dd[0] == DIFF_DELETE * factor) {
xx[1] = dd[1].length
ii += xx[1]
}
i++
}
}
x.push(xx)
}
return x
}
function get_diff_patch(a, b) {
return diff_convert_to_my_format(diff_main(a, b))
}
function get_diff_patch_2(a, b) {
var x = diff_main(a, b)
return [diff_convert_to_my_format(x),
diff_convert_to_my_format(x, -1)]
}
diffsync.get_diff_patch = get_diff_patch
diffsync.get_diff_patch_2 = get_diff_patch_2
/**
* This library modifies the diff-patch-match library by Neil Fraser
* by removing the patch and match functionality and certain advanced
* options in the diff function. The original license is as follows:
*
* ===
*
* Diff Match and Patch
*
* Copyright 2006 Google Inc.
* http://code.google.com/p/google-diff-match-patch/
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* The data structure representing a diff is an array of tuples:
* [[DIFF_DELETE, 'Hello'], [DIFF_INSERT, 'Goodbye'], [DIFF_EQUAL, ' world.']]
* which means: delete 'Hello', add 'Goodbye' and keep ' world.'
*/
var DIFF_DELETE = -1;
var DIFF_INSERT = 1;
var DIFF_EQUAL = 0;
/**
* Find the differences between two texts. Simplifies the problem by stripping
* any common prefix or suffix off the texts before diffing.
* @param {string} text1 Old string to be diffed.
* @param {string} text2 New string to be diffed.
* @param {Int} cursor_pos Expected edit position in text1 (optional)
* @return {Array} Array of diff tuples.
*/
function diff_main(text1, text2, cursor_pos) {
// Check for equality (speedup).
if (text1 == text2) {
if (text1) {
return [[DIFF_EQUAL, text1]];
}
return [];
}
// Check cursor_pos within bounds
if (cursor_pos < 0 || text1.length < cursor_pos) {
cursor_pos = null;
}
// Trim off common prefix (speedup).
var commonlength = diff_commonPrefix(text1, text2);
var commonprefix = text1.substring(0, commonlength);
text1 = text1.substring(commonlength);
text2 = text2.substring(commonlength);
// Trim off common suffix (speedup).
commonlength = diff_commonSuffix(text1, text2);
var commonsuffix = text1.substring(text1.length - commonlength);
text1 = text1.substring(0, text1.length - commonlength);
text2 = text2.substring(0, text2.length - commonlength);
// Compute the diff on the middle block.
var diffs = diff_compute_(text1, text2);
// Restore the prefix and suffix.
if (commonprefix) {
diffs.unshift([DIFF_EQUAL, commonprefix]);
}
if (commonsuffix) {
diffs.push([DIFF_EQUAL, commonsuffix]);
}
diff_cleanupMerge(diffs);
if (cursor_pos != null) {
diffs = fix_cursor(diffs, cursor_pos);
}
return diffs;
};
/**
* Find the differences between two texts. Assumes that the texts do not
* have any common prefix or suffix.
* @param {string} text1 Old string to be diffed.
* @param {string} text2 New string to be diffed.
* @return {Array} Array of diff tuples.
*/
function diff_compute_(text1, text2) {
var diffs;
if (!text1) {
// Just add some text (speedup).
return [[DIFF_INSERT, text2]];
}
if (!text2) {
// Just delete some text (speedup).
return [[DIFF_DELETE, text1]];
}
var longtext = text1.length > text2.length ? text1 : text2;
var shorttext = text1.length > text2.length ? text2 : text1;
var i = longtext.indexOf(shorttext);
if (i != -1) {
// Shorter text is inside the longer text (speedup).
diffs = [[DIFF_INSERT, longtext.substring(0, i)],
[DIFF_EQUAL, shorttext],
[DIFF_INSERT, longtext.substring(i + shorttext.length)]];
// Swap insertions for deletions if diff is reversed.
if (text1.length > text2.length) {
diffs[0][0] = diffs[2][0] = DIFF_DELETE;
}
return diffs;
}
if (shorttext.length == 1) {
// Single character string.
// After the previous speedup, the character can't be an equality.
return [[DIFF_DELETE, text1], [DIFF_INSERT, text2]];
}
// Check to see if the problem can be split in two.
var hm = diff_halfMatch_(text1, text2);
if (hm) {
// A half-match was found, sort out the return data.
var text1_a = hm[0];
var text1_b = hm[1];
var text2_a = hm[2];
var text2_b = hm[3];
var mid_common = hm[4];
// Send both pairs off for separate processing.
var diffs_a = diff_main(text1_a, text2_a);
var diffs_b = diff_main(text1_b, text2_b);
// Merge the results.
return diffs_a.concat([[DIFF_EQUAL, mid_common]], diffs_b);
}
return diff_bisect_(text1, text2);
};
/**
* Find the 'middle snake' of a diff, split the problem in two
* and return the recursively constructed diff.
* See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations.
* @param {string} text1 Old string to be diffed.
* @param {string} text2 New string to be diffed.
* @return {Array} Array of diff tuples.
* @private
*/
function diff_bisect_(text1, text2) {
// Cache the text lengths to prevent multiple calls.
var text1_length = text1.length;
var text2_length = text2.length;
var max_d = Math.ceil((text1_length + text2_length) / 2);
var v_offset = max_d;
var v_length = 2 * max_d;
var v1 = new Array(v_length);
var v2 = new Array(v_length);
// Setting all elements to -1 is faster in Chrome & Firefox than mixing
// integers and undefined.
for (var x = 0; x < v_length; x++) {
v1[x] = -1;
v2[x] = -1;
}
v1[v_offset + 1] = 0;
v2[v_offset + 1] = 0;
var delta = text1_length - text2_length;
// If the total number of characters is odd, then the front path will collide
// with the reverse path.
var front = (delta % 2 != 0);
// Offsets for start and end of k loop.
// Prevents mapping of space beyond the grid.
var k1start = 0;
var k1end = 0;
var k2start = 0;
var k2end = 0;
for (var d = 0; d < max_d; d++) {
// Walk the front path one step.
for (var k1 = -d + k1start; k1 <= d - k1end; k1 += 2) {
var k1_offset = v_offset + k1;
var x1;
if (k1 == -d || (k1 != d && v1[k1_offset - 1] < v1[k1_offset + 1])) {
x1 = v1[k1_offset + 1];
} else {
x1 = v1[k1_offset - 1] + 1;
}
var y1 = x1 - k1;
while (x1 < text1_length && y1 < text2_length &&
text1.charAt(x1) == text2.charAt(y1)) {
x1++;
y1++;
}
v1[k1_offset] = x1;
if (x1 > text1_length) {
// Ran off the right of the graph.
k1end += 2;
} else if (y1 > text2_length) {
// Ran off the bottom of the graph.
k1start += 2;
} else if (front) {
var k2_offset = v_offset + delta - k1;
if (k2_offset >= 0 && k2_offset < v_length && v2[k2_offset] != -1) {
// Mirror x2 onto top-left coordinate system.
var x2 = text1_length - v2[k2_offset];
if (x1 >= x2) {
// Overlap detected.
return diff_bisectSplit_(text1, text2, x1, y1);
}
}
}
}
// Walk the reverse path one step.
for (var k2 = -d + k2start; k2 <= d - k2end; k2 += 2) {
var k2_offset = v_offset + k2;
var x2;
if (k2 == -d || (k2 != d && v2[k2_offset - 1] < v2[k2_offset + 1])) {
x2 = v2[k2_offset + 1];
} else {
x2 = v2[k2_offset - 1] + 1;
}
var y2 = x2 - k2;