Final Comments for Week 5

Picha, Marianne (Marianne) mpicha at LUCENT.COM
Wed Jun 22 14:13:02 EDT 2005


Hi 

I'm trying to understand how H.248 supports UTF-8 string properties.
According to H.248 the string property is encoded as UTF-8 string.

UTF-8 encoding is defined by the following table:

Scalar Value 			1st Byte 2nd Byte 3rd Byte 4th Byte
00000000 0xxxxxxx 		0xxxxxxx
00000yyy yyxxxxxx 		110yyyyy 10xxxxxx
zzzzyyyy yyxxxxxx 		1110zzzz 10yyyyyy 10xxxxxx
000uuuuu zzzzyyyy yyxxxxxx 	11110uuu 10uuzzzz 10yyyyyy 10xxxxxx


I.e. all the character codes between x80 and xf7 need to be supported.

According to H.248 Annex B.2:

The ABNF in this section uses the VALUE construct (or lists of VALUE
constructs) to encode various package element values (properties, signal
parameters, etc.).

The VALUE is defined as follows:

  VALUE                = quotedString / 1*(SafeChar)
  SafeChar             = DIGIT / ALPHA / "+" / "-" / "&" /
                          "!" / "_" / "/" / "\'" / "?" / "@" /
                          "^" / "`" / "~" / "*" / "$" / "\" /
                          "(" / ")" / "%" / "|" / "."
  ALPHA                = %x41-5A / %x61-7A ; A-Z / a-z
  DIGIT                = %x30-39         ; 0-9
  quotedString         = DQUOTE *(SafeChar / RestChar/ WSP) DQUOTE
  RestChar             = ";" / "[" / "]" / "{" / "}" / ":" / "," / "#" /
                          "<" / ">" / "="
  WSP                  = SP / HTAB ; white space
  SP                   = %x20        ; space
  HTAB                 = %x09        ; horizontal tab
  DQUOTE               = %x22            ; " (Double Quote)


So I believe this excludes the x80-xff characters.

So the question is how to text encoding defined in Annex B to encode
UTF-8 strings?

Thanks,
Sasha
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