xml file parsing in C

[Marc Dubois]

hi,
is it possible to parse an XML file in C so that i can fulfill these
requirements :
1) replace all "<" and ">" signs inside the body of tag by a space, e.g. :
Example 1:
<fooblabla < bla </foo>

becomes

<fooblabla bla </foo>

Example 2:

<foo>blablabl a </foo>

becomes
<fooblablabla </foo>
2) Remove all extra spaces at the end of every line of the XML file
3) Replace all special characters ( Unicode or Hexadecimal characters) by a
space
I mean the XML file is not well formed if there are "<" and ">" signs a
little bit everywhere,
it is not a valid file in that case, so i do not think the use of a parser
would be appropriate in that case. (How would the parser react when it
encounters a < that does not correspond to the beginning of a tag ???)

Do you have an idea on how i can write a program to deal with these
requirements ?
Technical environment is : Unix, KSH, and C (gcc)

I am thinking of using the "sed" command instead, i can get rid of the extra
spaces and replace the special characters but i still do not know how to
deal with the extra ">" and "<" signs.

Thanks for your help.

[Clever Monkey]

Marc Dubois wrote:

hi,
is it possible to parse an XML file in C so that i can fulfill these
requirements :
1) replace all "<" and ">" signs inside the body of tag by a space, e.g. :

[...]

2) Remove all extra spaces at the end of every line of the XML file
3) Replace all special characters ( Unicode or Hexadecimal characters) by a
space

I mean the XML file is not well formed if there are "<" and ">" signs a
little bit everywhere,
it is not a valid file in that case, so i do not think the use of a parser
would be appropriate in that case. (How would the parser react when it
encounters a < that does not correspond to the beginning of a tag ???)

Do you have an idea on how i can write a program to deal with these
requirements ?
Technical environment is : Unix, KSH, and C (gcc)

I am thinking of using the "sed" command instead, i can get rid of the extra
spaces and replace the special characters but i still do not know how to
deal with the extra ">" and "<" signs.

Pretty much OT for this group. Try a newsgroup that deals with POSIX
tools, or try "man sed".

<state:off-topic>
Also, look at XML tidy/validation tools. HTML tidy has limited XML support.
</>

[james of tucson]

Marc Dubois wrote:

hi,
is it possible to parse an XML file in C

Of course it is "possible." Is it easy?
Depends on your experience writing parsers.
The XML grammar is not especially complicated
-- that's sort of the point of it.

If you are willing to take a canned solution, there is expat for C
http://www.jclark.com/xml/expat.html

However, your problem seems to be formatting and error correction, not
XML parsing. For example,

<fooblabla < bla </foo>

Is not XML.

<foo>blablabl a </foo>

Is not XML

2) Remove all extra spaces at the end of every line of the XML file

You don't need anything but an address of a char array and '\0' to do
that :-)

3) Replace all special characters ( Unicode or Hexadecimal characters) by a
space

This part might be an interesting problem.

I mean the XML file is not well formed if there are "<" and ">" signs a
little bit everywhere,

Right, so you realize this, and you realize that an XML parser will
simply choke on it and (maybe) tell you where the errors are :-)

it is not a valid file in that case, so i do not think the use of a parser
would be appropriate in that case. (How would the parser react when it
encounters a < that does not correspond to the beginning of a tag ???)

Hopefully, it will emit a diagnostic message ...

Do you have an idea on how i can write a program to deal with these
requirements ?
Technical environment is : Unix, KSH, and C (gcc)

I am thinking of using the "sed" command instead, i can get rid of the extra
spaces and replace the special characters but i still do not know how to
deal with the extra ">" and "<" signs.

You could use a lookahead technique since you always know what you want
to match. The naive approach I'd start with, would be to work the
tokens from the outer extremes to inner, maybe making a pass first just
to validate that the angle brackets all match up.

>
Thanks for your help.

I replied to your post because I work in a Java environment, and I
realize I am spoiled. Doing XML in java is too simple to warrant much
discussion. Doing an XML parser in C, on the other hand, from scratch,
would be a very interesting problem.

After considering it for about half a second, I'd look into the
difficulty level of using the Xerces-C++ library in a C app. Or the
XML::Parser perl module.

I realize you want to feed it invalid XML and correct errors; I know
from experience that you can use Xerces to a certain extent to locate
errors, so it might not be terribly hard to take that approach - make
passes through the xerces validator to find errors, fix them, and end up
with the ability to do SAX or DOM on the document for free.

I have never, ever, even considered touching Xerces-C++, so I don't know
if it has anything in common with Xerces-Java. The docs on the xerces
site make it look easy enough to use.

Somebody out there has done this, right?

[Rob Hoelz]

Just curious, why do you want to use C for this? I'm not bashing C,
(I love it), but this seems like the kind of task Perl was created
for.

--
-Rob Hoelz

On Tue, 12 Dec 2006 22:07:14 +0100 "Marc Dubois" <[e-mail]>
wrote:

hi,
is it possible to parse an XML file in C so that i can fulfill these
requirements :
1) replace all "<" and ">" signs inside the body of tag by a space,
e.g. : Example 1:
<fooblabla < bla </foo>

becomes

<fooblabla bla </foo>

Example 2:

<foo>blablabl a </foo>

becomes
<fooblablabla </foo>
2) Remove all extra spaces at the end of every line of the XML file
3) Replace all special characters ( Unicode or Hexadecimal
characters) by a space
I mean the XML file is not well formed if there are "<" and ">" signs
a little bit everywhere,
it is not a valid file in that case, so i do not think the use of a
parser would be appropriate in that case. (How would the parser react
when it encounters a < that does not correspond to the beginning of a
tag ???)

Do you have an idea on how i can write a program to deal with these
requirements ?
Technical environment is : Unix, KSH, and C (gcc)

I am thinking of using the "sed" command instead, i can get rid of
the extra spaces and replace the special characters but i still do
not know how to deal with the extra ">" and "<" signs.

Thanks for your help.

[Marc Dubois]

i dont know PErl
"Rob Hoelz" <ho***@wisc.edu wrote in message
news:2006121217 2417.133beba0@T heRing...

Just curious, why do you want to use C for this? I'm not bashing C,
(I love it), but this seems like the kind of task Perl was created
for.

--
-Rob Hoelz

On Tue, 12 Dec 2006 22:07:14 +0100 "Marc Dubois" <[e-mail]>
wrote:

>hi,
is it possible to parse an XML file in C so that i can fulfill these
requirements :
1) replace all "<" and ">" signs inside the body of tag by a space,
e.g. : Example 1:
<fooblabla < bla </foo>

becomes

<fooblabla bla </foo>

Example 2:

<foo>blablabl a </foo>

becomes
<fooblablabla </foo>
2) Remove all extra spaces at the end of every line of the XML file
3) Replace all special characters ( Unicode or Hexadecimal
characters) by a space
I mean the XML file is not well formed if there are "<" and ">" signs
a little bit everywhere,
it is not a valid file in that case, so i do not think the use of a
parser would be appropriate in that case. (How would the parser react
when it encounters a < that does not correspond to the beginning of a
tag ???)

Do you have an idea on how i can write a program to deal with these
requirements ?
Technical environment is : Unix, KSH, and C (gcc)

I am thinking of using the "sed" command instead, i can get rid of
the extra spaces and replace the special characters but i still do
not know how to deal with the extra ">" and "<" signs.

Thanks for your help.

[Rob Hoelz]

It's a good language; I'd consider learning it if I were you.

"Marc Dubois" <[e-mail] te:

i dont know PErl
"Rob Hoelz" <ho***@wisc.edu wrote in message
news:2006121217 2417.133beba0@T heRing...

Just curious, why do you want to use C for this? I'm not bashing C,
(I love it), but this seems like the kind of task Perl was created
for.

--
-Rob Hoelz

On Tue, 12 Dec 2006 22:07:14 +0100 "Marc Dubois" <[e-mail]>
wrote:

hi,
is it possible to parse an XML file in C so that i can fulfill
these requirements :
1) replace all "<" and ">" signs inside the body of tag by a space,
e.g. : Example 1:
<fooblabla < bla </foo>

becomes

<fooblabla bla </foo>

Example 2:

<foo>blablabl a </foo>

becomes
<fooblablabla </foo>
2) Remove all extra spaces at the end of every line of the XML file
3) Replace all special characters ( Unicode or Hexadecimal
characters) by a space
I mean the XML file is not well formed if there are "<" and ">"
signs a little bit everywhere,
it is not a valid file in that case, so i do not think the use of a
parser would be appropriate in that case. (How would the parser
react when it encounters a < that does not correspond to the
beginning of a tag ???)

Do you have an idea on how i can write a program to deal with these
requirements ?
Technical environment is : Unix, KSH, and C (gcc)

I am thinking of using the "sed" command instead, i can get rid of
the extra spaces and replace the special characters but i still do
not know how to deal with the extra ">" and "<" signs.

Thanks for your help.

--
-Rob Hoelz

[Default User]

Rob Hoelz wrote:

Just curious, why do you want to use C for this?

Please don't top-post. Your replies belong following or interspersed
with properly trimmed quotes. See the majority of other posts in the
newsgroup, or:
<http://www.caliburn.nl/topposting.html >

[Richard]

"Default User" <de***********@ yahoo.comwrites :

Rob Hoelz wrote:

>Just curious, why do you want to use C for this?

Please don't top-post. Your replies belong following or interspersed
with properly trimmed quotes. See the majority of other posts in the
newsgroup, or:
<http://www.caliburn.nl/topposting.html >

Lecturing on top posting is OT.

[John F]

Richard wrote:

"Default User" <de***********@ yahoo.comwrites :

>Rob Hoelz wrote:

>>Just curious, why do you want to use C for this?

Please don't top-post. Your replies belong following or
interspersed
with properly trimmed quotes. See the majority of other posts in
the
newsgroup, or:
<http://www.caliburn.nl/topposting.html >

Lecturing on top posting is OT.

It's somwehow ironic but: so is lecturing on OT :-)

--
Johannes
You can have it:
Quick, Accurate, Inexpensive.
Pick two.

[Keith Thompson]

"John F" <sp**@127.0.0.1 writes:

Richard wrote:

>"Default User" <de***********@ yahoo.comwrites :

>>Rob Hoelz wrote:

Just curious, why do you want to use C for this?

Please don't top-post. Your replies belong following or
intersperse d
with properly trimmed quotes. See the majority of other posts in
the
newsgroup, or:
<http://www.caliburn.nl/topposting.html >

Lecturing on top posting is OT.

It's somwehow ironic but: so is lecturing on OT :-)

By convention, meta-discussions about topicality are considered
topical.

In my opinion, discussions about how to post properly should also be
considered topical. If nobody ever complained about top-posting, we'd
end up with an ugly mixture of top-posting, bottom-posting,
mid-posting, and whatever other forms of posting some random person
decides Looks Really Cool. The newsgroup will become more difficult
to read, and those who spend the most time here will lose patience and
give up on the newsgroup. Since spending a lot of time here
correlates fairly strongly (but not perfectly) with expertise, I
suggest that this would be to the great detriment of the newsgroup.

Personally, I *usually* don't complain about top-posting unless I
happen to be replying to the article anyway.

Perhaps we should agree on a de facto standard tag, like "[TP]", for
articles that complain about top-posting without adding new content.
Or perhaps there should be a more generic tag for criticisms of
posting style. (In my opinion, articles that complain about posting
style *and* discuss C need no such tag.)

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.