Re: [xml] xmlReadMemory : error "Extra content at the end of the document"

[Andrew Hartley <andrew hartley bcs org uk>]

Ok, sorry.  I am using VS2005 and the code is in a Regular DLL using shared
MFC.  The version of LibXml2 that I am statically linking to is: 2-2.6.32+

I am loading the Xml from a resource within the DLL in the InitInstance():

------------------------------------------------------------------------------
            CWinApp::InitInstance();

        char szResName[]        = "#7001";
        char szResType[]        = "TAXONOMYXML";
        HMODULE hMod = AfxGetResourceHandle();

        //      Load the Xml resource:
        HRSRC hRes = FindResource(hMod, szResName, szResType);

        if (hRes)
        {
                HGLOBAL hBytes  = LoadResource(hMod, hRes);
                LPVOID  lpData  = LockResource(hBytes);
                LPBYTE  lpbData = (LPBYTE)lpData;

                m_pXbrlTaxonomy = new CXbrlTaxonomy(reinterpret_cast<const
char*>(lpbData));
        }
        return TRUE;
------------------------------------------------------------------------------

Which as you can see passes the string read to my classes CXbrlTaxonomy
constructor the code for which is:

------------------------------------------------------------------------------
CXbrlTaxonomy::CXbrlTaxonomy(const string sXml)
{
        ReadInXml(sXml);
}
------------------------------------------------------------------------------

The ReadInXml(...) [part] is:

------------------------------------------------------------------------------
void CXbrlTaxonomy::ReadInXml(const string sXml)
{
        xmlDocPtr pXmlDoc = xmlReadMemory(sXml.c_str(), (int)sXml.size(), "xml",
NULL, 0);

        if (pXmlDoc == NULL)
        {
                xmlErrorPtr pErr = xmlGetLastError();
                AfxMessageBox(pErr->message);
        }
        else
        {
                xmlXPathContextPtr pXPathCtx = xmlXPathNewContext(pXmlDoc);
                          ...

------------------------------------------------------------------------------

The xmlReadMemory(...) returns a valid pointer to an xmlDoc object when I
run the DLL in Debug mode, but when I switch to Release mode it returns
NULL.  This is probably down to the Xml being read from the resource and I
will add some code to stream this out to a file so that I may investigate
that.  The reason why I had parsed the sXml.c_str() to a char* and apended a
LF (0x0a) and then a null terminator was just attempting to see if the
std::string c_str() function was returning some trailing chars.

As requested if anyone can see a flaw in my code leading to the
xmlReadMemory(...) returning NULL PLEASE let me know ASAP.  If I find
anything I will post my findings back here, so that if anyone else has a
similar issue they will know how to resolve it.



Elvis Stansvik wrote:
> Hi,
>
> First of all, please always state your platform and libxml2 version
> when asking for help. Also provide a complete standalone code example
> of your problem.
>
> 2008/11/13 Andrew Hartley <andrew hartley bcs org uk>:
> > I have written a DLL with a large (size = 1318109 chars) XML stored as a
> > resource.  I read the XML into a std::string and load it with a call to
> > xmlReadMemory:
> >
> > xmlDocPtr pXmlDoc = xmlReadMemory(sXml, sXml.length(), "xml", NULL, 0);
>
> This will never work. libxml2 is C not C++ and the API only works with
> NULL terminated sequences of UTF-8 bytes, not STL strings.
>
> > This works fine in Debug mode.  But when I switch to Release mode I get
> > NULL
> > returned and the error text is "Extra content at the end of the
> > document".
> >
> > I have tried parsing the std::string content into a char*, and setting
> > the
> > argv[3] to "UTF-8":
> >
> >             int nLen = (int)sXml.size();
> >        char* pszContent        = new char[nLen +2];
> >
> >        strcpy_s(pszContent, nLen +2, sXml.c_str());
> >        pszContent[nLen]                = '\n';
> >        pszContent[nLen +1]     = '\0';
> >
> >        xmlDocPtr pXmlDoc = xmlReadMemory(pszContent, nLen, "xml",
> > "UTF-8", 0);
> >
> >        delete[] pszContent;
> >        pszContent = NULL;
> >
> > But I still get the same error!
>
> Your example works here (libxml2 on GNU/Linux):
>
> #include <string.h>
> #include <libxml/parser.h>
> #include <iostream>
>
> int main (int argc, char *argv[])
> {
>     LIBXML_TEST_VERSION
>
>     std::string sXml("<foo/>");
>     int nLen = (int)sXml.size();
>     char* pszContent = new char[nLen + 2];
>
>     strncpy(pszContent, sXml.c_str(), nLen + 2);
>     pszContent[nLen] = '\n';
>     pszContent[nLen + 1] = '\0';
>
>     xmlDocPtr pXmlDoc = xmlReadMemory(pszContent, nLen, "xml", "UTF-8",
> 0);
>     if (pXmlDoc == NULL)
>         return(1);
>
>     delete[] pszContent;
>     pszContent = NULL;
>
>     xmlFreeDoc(pXmlDoc);
>     xmlCleanupParser();
>
>     return(0);
> }
>
> [astan franz ~]$ g++ -o test `xml2-config --libs --cflags` test.cpp
> [astan franz ~]$ ./test
> [astan franz ~]$ echo $?
> 0
> [astan franz ~]$
>
> Though the reason you are adding an extra newline after the XML eludes
> me at the moment. Note that I had to use strncpy instead of strcpy_s,
> as I'm on GNU/Linux where strcpy_s doesn't exist.
>
> Regards,
> Elvis
>
> > I have not resorted to attemting to debug through LibXml2 yet, and would
> > appreciate any advice.
> > --
> > View this message in context:
> > http://www.nabble.com/xmlReadMemory-%3A-error-%22Extra-content-at-the-end-of-the-document%22-tp20484750p20484750.html
> > Sent from the Gnome - Lib - Xml - General mailing list archive at
> > Nabble.com.
> >
> > _______________________________________________
> > xml mailing list, project page  http://xmlsoft.org/
> > xml gnome org
> > http://mail.gnome.org/mailman/listinfo/xml
> _______________________________________________
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