Alberto Massari wrote:
> 3) if you don't option 2, you have to do the conversion at runtime
> using a transcoder, like in
>
> const XMLCh* gFileToTrap=XMLString::transcode("personal.dtd");
>
> Don't forget to delete the string by using
> XMLString::release(&gFileToTrap); also, you must allocate it after
> XMLPlatformUtils::initialize and deallocate it before
> XMLPlatformUtils::terminate.
Hi Rafael,
I have good experience in using a little wrapper class around XMLCh. I
called it XML_Char, and I use it like the following examples:
XML_Char empty; // empty string
XML_Char text("hello"); // initialized from const char*
XML_Char attr = node->getAttribute(XML_Char("id"));
// initialized from const XMLCh*
XML_Char copy(text); // copy constructor
empty = text; // assignment
text = "go away"; // implicit construction and assignment
Each object of the XML_Char class has a representation in char* and in
XMLCh*, and the destructor/assignment operator keeps track of freeing
the memory used. The class has inlined
operator const XMLCh*() const
operator const char*() const
referencing operators, so you can use the objects simultaneously as const
char*- or const XMLCh*-strings. Additionally, I have some convenience
operators like
unsigned len() const // equ. to strlen(.)
operator bool () const // test if string is empty
char operator[](unsigned i) const // indexing (rarely used)
friend std::ostream &operator<<(std::ostream &o, const XML_Char &c)
// stream output
There are some disadvantages, which must be kept in mind when using
XML_Char:
- you can't declare global objects, since XMLPlatformUtils::initialize
will be called _after_ construction, and the conversion during
construction will crash the program.
- there's some overhead, resulting from the dual representation, which
is not used in every scenario.
- undefined behaviour when the string contains letters which are not
representable in the local code page. This can be eliminated by using
utf-8 as the local encoding.
The reason why I use this class in all my xerces-related projects, are
the advantages:
- no memory leaks due to string handling/transcoding
- automatic transcoding between XMLCh and local code page
- convenient string handling when dealing with DOM/SAX.
- the whole class is inlined (header file only)
- the implementation is optimized for _my_ needs ;)
Rafael, if you are a lazy guy, you may ask me for a copy of the class
XML_Char - it's open source. But if you are keen, you sit down and write
your own, it will take you little effort (and you can optimize it for
_your_ needs).
Cheers,
Axel
