String encodings.

class Encoding {
 static const Encoding UTF_8 = const Encoding._internal("utf-8");
 static const Encoding ISO_8859_1 = const Encoding._internal("iso-8859-1");
 static const Encoding ASCII = const Encoding._internal("us-ascii");

 /**
  * SYSTEM encoding is the current code page on Windows and UTF-8 on
  * Linux and Mac.
  */
 static const Encoding SYSTEM = const Encoding._internal("system");

 // All aliasses (in lowercase) of supported encoding from
 // http://www.iana.org/assignments/character-sets/character-sets.xml.
 static Map<String, Encoding> _nameToEncoding = <String, Encoding> {
   // ISO_8859-1:1987.
   "iso_8859-1:1987": ISO_8859_1,
   "iso-ir-100": ISO_8859_1,
   "iso_8859-1": ISO_8859_1,
   "iso-8859-1": ISO_8859_1,
   "latin1": ISO_8859_1,
   "l1": ISO_8859_1,
   "ibm819": ISO_8859_1,
   "cp819": ISO_8859_1,
   "csisolatin1": ISO_8859_1,

   // US-ASCII.
   "iso-ir-6": ASCII,
   "ansi_x3.4-1968": ASCII,
   "ansi_x3.4-1986": ASCII,
   "iso_646.irv:1991": ASCII,
   "iso646-us": ASCII,
   "us-ascii": ASCII,
   "us": ASCII,
   "ibm367": ASCII,
   "cp367": ASCII,
   "csascii": ASCII,
   "ascii": ASCII,  // This is not in the IANA official names.

   // UTF-8.
   "csutf8": UTF_8,
   "utf-8": UTF_8
 };

 /**
  * Gets an [Encoding] object from the name of the character set
  * name. The names used are the IANA official names for the
  * character set (see
  * http://www.iana.org/assignments/character-sets/character-sets.xml).
  *
  * The [name] passed is case insensitive.
  *
  * If character set is not supported [:null:] is returned.
  */
 static Encoding fromName(String name) {
   if (name == null) return null;
   name = name.toLowerCase();
   return _nameToEncoding[name];
 }

 /**
  * Name of the encoding. This will be the lower-case version of one of the
  * IANA official names for the character set (see
  * http://www.iana.org/assignments/character-sets/character-sets.xml)
  */
 final String name;

 const Encoding._internal(String this.name);
}