From 581264c5e342a58657020559702d9fd43202fa2b Mon Sep 17 00:00:00 2001
From: Kevin Jahns <kevin.jahns@rwth-aachen.de>
Date: Fri, 29 Sep 2017 22:33:28 +0200
Subject: [PATCH] implement relative position helper

---
 examples/html-editor/index.js |  3 +--
 src/Utils.js                  | 45 +++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/examples/html-editor/index.js b/examples/html-editor/index.js
index b5df0eea..db4bd6ff 100644
--- a/examples/html-editor/index.js
+++ b/examples/html-editor/index.js
@@ -7,8 +7,7 @@ Y({
   },
   connector: {
     name: 'websockets-client',
-    // url: 'http://127.0.0.1:1234',
-    url: 'http://192.168.178.81:1234',
+    url: 'http://127.0.0.1:1234',
     room: 'html-editor-example6'
   },
   share: {
diff --git a/src/Utils.js b/src/Utils.js
index a80f3808..823353b4 100644
--- a/src/Utils.js
+++ b/src/Utils.js
@@ -49,6 +49,51 @@ export default function Utils (Y) {
     }
   }
 
+  Y.utils.getRelativePosition = function (type, offset) {
+    if (type == null) {
+      return null
+    } else {
+      if (type._content.length <= offset) {
+        return ['endof', type._model[0], type._model[1]]
+      } else {
+        return type._content[offset].id
+      }
+    }
+  }
+
+  Y.utils.fromRelativePosition = function (y, id) {
+    var offset = 0
+    var op
+    if (id[0] === 'endof') {
+      id = y.db.os.find(id.slice(1)).end
+      op = y.db.os.findNodeWithUpperBound(id).val
+      if (!op.deleted) {
+        offset = op.content != null ? op.content.length : 1
+      }
+    } else {
+      op = y.db.os.findNodeWithUpperBound(id).val
+      if (!op.deleted) {
+        offset = id[1] - op.id[1]
+      }
+    }
+
+    var type = y.db.getType(op.parent)
+    if (type == null || y.db.os.find(op.parent).deleted) {
+      return null
+    }
+
+    while (op.left != null) {
+      op = y.db.os.findNodeWithUpperBound(op.left).val
+      if (!op.deleted) {
+        offset += op.content != null ? op.content.length : 1
+      }
+    }
+    return {
+      type: type,
+      offset: offset
+    }
+  }
+
   class NamedEventHandler {
     constructor () {
       this._eventListener = {}