1 files changed, 167 insertions, 0 deletions
diff --git a/trunk/infrastructure/com.etherpad/easysync2support.scala b/trunk/infrastructure/com.etherpad/easysync2support.scala
new file mode 100644
index 0000000..9f1c527
--- /dev/null
+++ b/trunk/infrastructure/com.etherpad/easysync2support.scala
@@ -0,0 +1,167 @@
+/**
+ * Copyright 2009 Google Inc.
+ * 
+ * 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.
+ */
+
+package com.etherpad;
+
+object Easysync2Support {
+
+  def numToString(d: Int): String = java.lang.Integer.toString(d.toInt, 36); // lowercase
+  def stringToNum(s: String): Int = java.lang.Integer.parseInt(s, 36);
+  
+  def opAssembler() = new OpAssembler();
+  
+  class OpAssembler() {
+    val buf = new StringBuilder(1000);
+    def append(op: Op) {
+      append(op.opcode, op.chars, op.lines, op.attribs);
+    }
+    def append(opcode: String, chars: Int, lines: Int, attribs: String) {
+      buf.append(attribs);
+      if (lines > 0) {
+        buf.append('|');
+        buf.append(numToString(lines));
+      }
+      buf.append(opcode);
+      buf.append(numToString(chars));
+    }
+    override def toString(): String = buf.toString;
+    def clear() { buf.clear; }
+  }
+
+  def isAlphanum(c: Char) = (c >= '0' && c <= '9' || c >= 'a' && c <= 'z');
+
+  case object OpParseError extends Error;  
+  
+  def nextOpInString(str: String, startIndex: Int): Object = {
+    var i = startIndex;
+
+    try {
+      def lookingAt(c: Char) = (i < str.length && str.charAt(i) == c);
+      def lookingAtAlphanum() = (i < str.length && isAlphanum(str.charAt(i)));
+      def atEnd() = (i >= str.length);
+      def readAlphanum(): Int = {
+        if (! lookingAtAlphanum()) {
+          throw OpParseError;
+        }
+        val start = i;
+        while (lookingAtAlphanum()) {
+          i += 1;
+        }
+        val end = i;
+        stringToNum(str.substring(start, end));
+      }
+      
+      while (lookingAt('*')) {
+        i += 1;
+        if (! lookingAtAlphanum()) {
+          throw OpParseError;
+        }
+        while (lookingAtAlphanum()) {
+          i += 1;
+        }
+      }
+      val attribsEnd = i;
+      
+      var lines_ = 0;
+      if (lookingAt('|')) {
+        i += 1;
+        lines_ = readAlphanum();
+      }
+      
+      if (lookingAt('?')) {
+        return new { val opcode = "?"; }
+      }
+      if (! (lookingAt('+') || lookingAt('-') || lookingAt('='))) {
+        throw OpParseError;
+      }
+      val opcode_ = str.substring(i, i+1);
+      i += 1;
+      val chars_ = readAlphanum();
+
+      return new Op(opcode_, chars_, lines_, str.substring(startIndex, attribsEnd)) {
+        val lastIndex = i;
+      };
+    }
+    catch { case OpParseError => null }
+  }
+
+  case class Op(var opcode: String, var chars: Int, var lines: Int, var attribs: String);
+  def newOp() = Op("", 0, 0, "");
+  def clearOp(op: Op) { op.opcode = ""; op.chars = 0; op.lines = 0; op.attribs = ""; }
+  
+  // ported from easysync2.js
+  class MergingOpAssembler {
+    val assem = opAssembler();
+    var bufOp = newOp();
+
+    var bufOpAdditionalCharsAfterNewline = 0;
+
+    def flush(isEndDocument: Boolean) {
+      if (bufOp.opcode.length > 0) {
+        if (isEndDocument && bufOp.opcode == "=" && bufOp.attribs.length == 0) {
+          // final merged keep, leave it implicit
+        }
+        else {
+          assem.append(bufOp);
+          if (bufOpAdditionalCharsAfterNewline > 0) {
+            bufOp.chars = bufOpAdditionalCharsAfterNewline;
+            bufOp.lines = 0;
+            assem.append(bufOp);
+            bufOpAdditionalCharsAfterNewline = 0;
+          }
+        }
+        bufOp.opcode = "";
+      }
+    }
+    def append(opcode: String, chars: Int, lines: Int, attribs: String) {
+      if (chars > 0) {
+        if (bufOp.opcode == opcode && bufOp.attribs == attribs) {
+	  if (lines > 0) {
+	    // bufOp and additional chars are all mergeable into a multi-line op
+	    bufOp.chars += bufOpAdditionalCharsAfterNewline + chars;
+	    bufOp.lines += lines;
+	    bufOpAdditionalCharsAfterNewline = 0;
+	  }
+	  else if (bufOp.lines == 0) {
+	    // both bufOp and op are in-line
+	    bufOp.chars += chars;
+	  }
+	  else {
+	    // append in-line text to multi-line bufOp
+	    bufOpAdditionalCharsAfterNewline += chars;
+	  }
+        }
+        else {
+	  flush(false);
+          bufOp = Op(opcode, chars, lines, attribs);
+        }
+      }
+    }
+    def endDocument() {
+      flush(true);
+    }
+    override def toString() = {
+      flush(false);
+      assem.toString();
+    }
+    def clear() {
+      assem.clear();
+      clearOp(bufOp);
+    }
+  }
+
+  def mergingOpAssembler() = new MergingOpAssembler();
+}