Fix argument processing for RandomAccessFile.writeFrom

sdk/lib/io/file.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.io;
 
 /**
  * The modes in which a File can be opened.
  */
 class FileMode {
@@ skipping 555 matching lines @@
 
   /**
    * Reads into an existing List<int> from the file. If [start] is present, the
    * bytes will be filled into [buffer] from at index [start], otherwise index
    * 0. If [end] is present, the [end] - [start] bytes will be read into
    * [buffer], otherwise up to [buffer.length]. If [end] == [start] nothing
    * happends.
    *
    * Returns a [:Future<int>:] that completes with the number of bytes read.
    */
-  Future<int> readInto(List<int> buffer, [int start, int end]);
+  Future<int> readInto(List<int> buffer, [int start = 0, int end]);
 
   /**
    * Synchronously reads into an existing List<int> from the file. If [start] is
    * present, the bytes will be filled into [buffer] from at index [start],
    * otherwise index 0.  If [end] is present, the [end] - [start] bytes will be
    * read into [buffer], otherwise up to [buffer.length]. If [end] == [start]
    * nothing happends.
    *
    * Throws a [FileSystemException] if the operation fails.
    */
-  int readIntoSync(List<int> buffer, [int start, int end]);
+  int readIntoSync(List<int> buffer, [int start = 0, int end]);
 
   /**
    * Writes a single byte to the file. Returns a
    * [:Future<RandomAccessFile>:] that completes with this
    * RandomAccessFile when the write completes.
    */
   Future<RandomAccessFile> writeByte(int value);
 
   /**
    * Synchronously writes a single byte to the file. Returns the
    * number of bytes successfully written.
    *
    * Throws a [FileSystemException] if the operation fails.
    */
   int writeByteSync(int value);
 
   /**
    * Writes from a [List<int>] to the file. It will read the buffer from index
    * [start] to index [end]. If [start] is omitted, it'll start from index 0.
    * If [end] is omitted, it will write to end of [buffer].
    *
    * Returns a [:Future<RandomAccessFile>:] that completes with this
    * [RandomAccessFile] when the write completes.
    */
-  Future<RandomAccessFile> writeFrom(List<int> buffer, [int start, int end]);
+  Future<RandomAccessFile> writeFrom(
+      List<int> buffer, [int start = 0, int end]);
 
   /**
    * Synchronously writes from a [List<int>] to the file. It will read the
    * buffer from index [start] to index [end]. If [start] is omitted, it'll
    * start from index 0. If [end] is omitted, it will write to the end of
    * [buffer].
    *
    * Throws a [FileSystemException] if the operation fails.
    */
-  void writeFromSync(List<int> buffer, [int start, int end]);
+  void writeFromSync(List<int> buffer, [int start = 0, int end]);
 
   /**
    * Writes a string to the file using the given [Encoding]. Returns a
    * [:Future<RandomAccessFile>:] that completes with this
    * RandomAccessFile when the write completes.
    */
   Future<RandomAccessFile> writeString(String string,
                                        {Encoding encoding: UTF8});
 
   /**
@@ skipping 228 matching lines @@
       sb.write(": $osError");
       if (path != null) {
         sb.write(", path = '$path'");
       }
     } else if (path != null) {
       sb.write(": $path");
     }
     return sb.toString();
   }
 }