optimize --embed-file

Author: kripken

tools/file_packager.py

@@ -416,10 +416,13 @@ def was_seen(name):
     data = map(ord, open(file_['srcpath'], 'rb').read())
     code += '''fileData%d = [];\n''' % counter
     if data:
+      parts = []
       chunk_size = 10240
-      while len(data) > 0:
-        code += '''fileData%d.push.apply(fileData%d, %s);\n''' % (counter, counter, str(data[:chunk_size]))
-        data = data[chunk_size:]
+      start = 0
+      while start < len(data):
+        parts.append('''fileData%d.push.apply(fileData%d, %s);\n''' % (counter, counter, str(data[start:start+chunk_size])))
+        start += chunk_size
+      code += ''.join(parts)
     code += '''Module['FS_createDataFile']('%s', '%s', fileData%d, true, true);\n''' % (dirname, basename, counter)
     counter += 1
   elif file_['mode'] == 'preload':