Re: parsing XML with 'expat'
 

* Roman Mashak wrote in comp.text.xml:
>I hope this might be the right group to ask. I need to parse out in C
>language the XML of the following structure:
>
><BERTEST>
> <NODE1>
> <FREQ>666000000</FREQ>
> <POWER>-82</POWER>
> </NODE1>
> <NODE1>
> <FREQ>484000000</FREQ>
> <POWER>-80</POWER>
> </NODE2>
></BERTEST>
>
>So I took the 'expat' library to do that (I've never dealt with XML before
>though), and tried to cutomize the example they ship with library
>(outline.c). What I can't quite understand is:
>1) is my XML really can be called XML, or it's some sort of invalid?
>According to wikipedia page on XML, the valid document should look like
>this:
>
><name attribute="value">content</name>
>
>while mine is a bit different

Your second <NODE1> should probably be <NODE2> (otherwise the start- and
end-tags do not match up), but other than that it certainly is XML. You
are free to choose (when designing a new XML format) whether you use an
attribute or element to encode some information.

>2) if anyway my xml document is correct, then how can I parse it with expat?
>What I need is upon occurences of FREQ and POWER tags to extract their
>values (i.e. 666000000 for FREQ or 082 for POWER in the above example).
>
>So, I think I need to register callback function for start tags and try to
>do what I want in there. But how can I get the values of tags, which 'expat'
>functions to use? Or there's another, more simple way?

Expart reports the text through the `characters` callback. You have to
setup a handler for it and accumulate the text reported to it; then
process the text e.g. in the end_element handler. There is no direct way
get to the text when using Expat.
--
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Weinh. Str. 22 · Telefon: +49(0)621/4309674 · http://www.bjoernsworld.de
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Re: parsing XML with 'expat'
 

Roman Mashak wrote:

> 2) if anyway my xml document is correct, then how can I parse it with expat?
> What I need is upon occurences of FREQ and POWER tags to extract their
> values (i.e. 666000000 for FREQ or 082 for POWER in the above example).

What do you do with the extracted text ?
Do you put it into a text file for further
processing ? Then you can use any scripting
languag that is easier to use than the Expat
at C level.

For example, you can try this one:

http://home.vrweb.de/~juergen.kahrs/...of-an-XML-file

@load xml
XMLSTARTELEM {
printf("%*s%s", 2*XMLDEPTH-2, "", XMLSTARTELEM)
for (i=1; i<=NF; i++)
printf(" %s='%s'", $i, XMLATTR[$i])
print ""
}

This script does exactly what the outline.c example
from Expat does.

parsing XML with 'expat'
 

Hello,

I hope this might be the right group to ask. I need to parse out in C
language the XML of the following structure:

<BERTEST>
<NODE1>
<FREQ>666000000</FREQ>
<POWER>-82</POWER>
</NODE1>
<NODE1>
<FREQ>484000000</FREQ>
<POWER>-80</POWER>
</NODE2>
</BERTEST>

So I took the 'expat' library to do that (I've never dealt with XML before
though), and tried to cutomize the example they ship with library
(outline.c). What I can't quite understand is:
1) is my XML really can be called XML, or it's some sort of invalid?
According to wikipedia page on XML, the valid document should look like
this:

<name attribute="value">content</name>

while mine is a bit different

2) if anyway my xml document is correct, then how can I parse it with expat?
What I need is upon occurences of FREQ and POWER tags to extract their
values (i.e. 666000000 for FREQ or 082 for POWER in the above example).

So, I think I need to register callback function for start tags and try to
do what I want in there. But how can I get the values of tags, which 'expat'
functions to use? Or there's another, more simple way?

Thanks in advance

--
Best regards, Roman