Re: [xml] Query regardin storing of encoding information

[Daniel Veillard <veillard redhat com>]

On Wed, Apr 23, 2008 at 11:28:01AM +0800, Ashwin wrote:
> >  We store the encoding of the document as advertized in the
> > xml declaration in the document encoding itself.
>
> > Breakpoint 1, xmlFreeDoc (cur=0x725d98) at tree.c:1175
> > 1175    xmlFreeDoc(xmlDocPtr cur) {
> > (gdb) p cur->encoding
> > $1 = (const xmlChar *) 0x725ed8 "ISO-8859-1"
> > (gdb) 
>
> Hi,
>   Suppose I am using Sax callbacks for parsing, in that case if I want to
> know the encoding specified in the xml declaration, I will try to retrieve
> it from ctxt->encoding, however ctxt->encoding is set to only UTF-8 or
> UTF-16, depending on whichever is specified in the xml declaration. In case
> the xml declaration specifies any other encoding, for instance GB2312, then
> ctxt->encoding will be NULL, while ctxt->input->encoding will be set to
> GB2312. 
>
> My doubt is in the function xmlParseEncodingDecl, ctxt->encoding is not set
> to the encoding specified in the xml declaration if its not UTF-8 or
> UTF-16...
>
> The function checks if the encoding specified in the xml declaration is
> UTF-8 or UTF-16, and sets ctxt->encoding if that is the case else it sets 
> ctxt->input->encoding to the encoding specified in the xml declaration while
> ctxt->encoding is NULL.
>
> Is there any specific reason for this? 

  Not that I remember. But basically if you use SAX, this means that you're
doing input only of the document, don't plan to save it and hence the 
original encoding is not useful. 
  I don't have any good explanation for not setting ctxt->encoding, this
value is checked in a number of places but I can't think right now why this
would be a problem.

Daniel

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