Make gen files more human-readable by using a string initializer

runtime/tools/create_string_literal.py

Index: runtime/tools/create_string_literal.py
===================================================================
--- runtime/tools/create_string_literal.py	(revision 4233)
+++ runtime/tools/create_string_literal.py	(working copy)
@@ -13,21 +13,32 @@
 
 
 def makeString(input_files):
+  printable = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ\
+!#$%&'()*+,-./:;<=>?@[]^_`{|}~ "
   result = ' '
+  lineNumber = 1
   for string_file in input_files:
     if string_file.endswith('dart'):
       fileHandle = open(string_file, 'rb')
-      lineCounter = 0
-      result += ' // ' + string_file + '\n   '
+      quoted = False
+      result += '\n  // ----- ' + string_file + ' -----\n\n'
       for byte in fileHandle.read():
-        result += ' %d,' % ord(byte)
-        lineCounter += 1
-        if lineCounter == 10:
-          result += '\n   '
-          lineCounter = 0
-      if lineCounter != 0:
-        result += '\n   '
-  result += ' // Terminating null character.\n    0'
+        if not quoted:
+          result += '  "'
+          quoted = True
+        if byte in printable:
+          result += byte
+        elif byte == '\n':
+          if lineNumber % 10 == 0:
+            result += '\\n" /* L%d */\n' % lineNumber
+          else:
+            result += '\\n"\n'
+          lineNumber += 1
+          quoted = False
+        elif byte == '\"':
+          result += '\\"'
+        else:
+          result += '\\x%02x' % ord(byte)
   return result