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TinyXML is a simple, small, C++ XML parser that can be easily integrated into other programs.
In brief, TinyXML parses an XML document, and builds from that a Document Object Model (DOM) that can be read, modified, and saved.
XML stands for "eXtensible Markup Language." It allows you to create your own document markups. Where HTML does a very good job of marking documents for browsers, XML allows you to define any kind of document markup, for example a document that describes a "to do" list for an organizer application. XML is a very structured and convenient format. All those random file formats created to store application data can all be replaced with XML. One parser for everything.
The best place for the complete, correct, and quite frankly hard to read spec is at http://www.w3.org/TR/2004/REC-xml-20040204/. An intro to XML (that I really like) can be found at http://skew.org/xml/tutorial.
There are different ways to access and interact with XML data. TinyXML uses a Document Object Model (DOM), meaning the XML data is parsed into a C++ objects that can be browsed and manipulated, and then written to disk or another output stream. You can also construct an XML document from scratch with C++ objects and write this to disk or another output stream.
TinyXML is designed to be easy and fast to learn. It is two headers and four cpp files. Simply add these to your project and off you go. There is an example file - xmltest.cpp - to get you started.
TinyXML is released under the ZLib license, so you can use it in open source or commercial code. The details of the license are at the top of every source file.
TinyXML attempts to be a flexible parser, but with truly correct and compliant XML output. TinyXML should compile on any reasonably C++ compliant system. It does not rely on exceptions or RTTI. It can be compiled with or without STL support. TinyXML fully supports the UTF-8 encoding, and the first 64k character entities.
TinyXML doesn't parse or use DTDs (Document Type Definitions) or XSLs (eXtensible Stylesheet Language.) There are other parsers out there (check out www.sourceforge.org, search for XML) that are much more fully featured. But they are also much bigger, take longer to set up in your project, have a higher learning curve, and often have a more restrictive license. If you are working with browsers or have more complete XML needs, TinyXML is not the parser for you.
The following DTD syntax will not parse at this time in TinyXML:
@verbatim <!DOCTYPE Archiv [ <!ELEMENT Comment (#PCDATA)> ]> @endverbatim
because TinyXML sees this as a !DOCTYPE node with an illegally embedded !ELEMENT node. This may be addressed in the future.
For the impatient, here are some tutorials to get you going. A great way to get started, but it is worth your time to read this (very short) manual completely.
TinyXML is mature, tested code. It is very stable. If you find bugs, please file a bug report on the sourceforge web site (www.sourceforge.net/projects/tinyxml). We'll get them straightened out as soon as possible.
There are some areas of improvement; please check sourceforge if you are interested in working on TinyXML.
TinyXML projects you may find useful! (Descriptions provided by the projects.)
TinyXML can be compiled to use or not use STL. When using STL, TinyXML uses the std::string class, and fully supports std::istream, std::ostream, operator<<, and operator>>. Many API methods have both 'const char*' and 'const std::string&' forms.
When STL support is compiled out, no STL files are included whatsoever. All the string classes are implemented by TinyXML itself. API methods all use the 'const char*' form for input.
Use the compile time #define:
TIXML_USE_STLto compile one version or the other. This can be passed by the compiler, or set as the first line of "tinyxml.h".
Note: If compiling the test code in Linux, setting the environment variable TINYXML_USE_STL=YES/NO will control STL compilation. In the Windows project file, STL and non STL targets are provided. In your project, It's probably easiest to add the line "#define TIXML_USE_STL" as the first line of tinyxml.h.
TinyXML supports UTF-8 allowing to manipulate XML files in any language. TinyXML also supports "legacy mode" - the encoding used before UTF-8 support and probably best described as "extended ascii".
Normally, TinyXML will try to detect the correct encoding and use it. However, by setting the value of TIXML_DEFAULT_ENCODING in the header file, TinyXML can be forced to always use one encoding.
TinyXML will assume Legacy Mode until one of the following occurs:
What happens if the encoding is incorrectly set or detected? TinyXML will try to read and pass through text seen as improperly encoded. You may get some strange results or mangled characters. You may want to force TinyXML to the correct mode.
You may force TinyXML to Legacy Mode by using LoadFile( TIXML_ENCODING_LEGACY ) or LoadFile( filename, TIXML_ENCODING_LEGACY ). You may force it to use legacy mode all the time by setting TIXML_DEFAULT_ENCODING = TIXML_ENCODING_LEGACY. Likewise, you may force it to TIXML_ENCODING_UTF8 with the same technique.
For English users, using English XML, UTF-8 is the same as low-ASCII. You don't need to be aware of UTF-8 or change your code in any way. You can think of UTF-8 as a "superset" of ASCII.
UTF-8 is not a double byte format - but it is a standard encoding of Unicode! TinyXML does not use or directly support wchar, TCHAR, or Microsoft's _UNICODE at this time. It is common to see the term "Unicode" improperly refer to UTF-16, a wide byte encoding of unicode. This is a source of confusion.
For "high-ascii" languages - everything not English, pretty much - TinyXML can handle all languages, at the same time, as long as the XML is encoded in UTF-8. That can be a little tricky, older programs and operating systems tend to use the "default" or "traditional" code page. Many apps (and almost all modern ones) can output UTF-8, but older or stubborn (or just broken) ones still output text in the default code page.
For example, Japanese systems traditionally use SHIFT-JIS encoding. Text encoded as SHIFT-JIS can not be read by TinyXML. A good text editor can import SHIFT-JIS and then save as UTF-8.
The Skew.org link does a great job covering the encoding issue.
The test file "utf8test.xml" is an XML containing English, Spanish, Russian, and Simplified Chinese. (Hopefully they are translated correctly). The file "utf8test.gif" is a screen capture of the XML file, rendered in IE. Note that if you don't have the correct fonts (Simplified Chinese or Russian) on your system, you won't see output that matches the GIF file even if you can parse it correctly. Also note that (at least on my Windows machine) console output is in a Western code page, so that Print() or printf() cannot correctly display the file. This is not a bug in TinyXML - just an OS issue. No data is lost or destroyed by TinyXML. The console just doesn't render UTF-8.
TinyXML recognizes the pre-defined "character entities", meaning special characters. Namely:
@verbatim & & < < > > " " ' ' @endverbatim
These are recognized when the XML document is read, and translated to there UTF-8 equivalents. For instance, text with the XML of:
@verbatim Far & Away @endverbatim
will have the Value() of "Far & Away" when queried from the TiXmlText object, and will be written back to the XML stream/file as an ampersand. Older versions of TinyXML "preserved" character entities, but the newer versions will translate them into characters.
Additionally, any character can be specified by its Unicode code point: The syntax " " or " " are both to the non-breaking space characher.
TinyXML can print output in several different ways that all have strengths and limitations.
Print( FILE* ). Output to a std-C stream, which includes all C files as well as stdout.
operator<<. Output to a c++ stream.
TiXmlPrinter. Output to a std::string or memory buffer.
With TIXML_USE_STL on TinyXML supports C++ streams (operator <<,>>) streams as well as C (FILE*) streams. There are some differences that you may need to be aware of.
C style output:
the Print() and SaveFile() methods
Generates formatted output, with plenty of white space, intended to be as human-readable as possible. They are very fast, and tolerant of ill formed XML documents. For example, an XML document that contains 2 root elements and 2 declarations, will still print.
C style input:
the Parse() and LoadFile() methods
A fast, tolerant read. Use whenever you don't need the C++ streams.
C++ style output:
operator<<
Generates condensed output, intended for network transmission rather than readability. Depending on your system's implementation of the ostream class, these may be somewhat slower. (Or may not.) Not tolerant of ill formed XML: a document should contain the correct one root element. Additional root level elements will not be streamed out.
C++ style input:
operator>>
Reads XML from a stream, making it useful for network transmission. The tricky part is knowing when the XML document is complete, since there will almost certainly be other data in the stream. TinyXML will assume the XML data is complete after it reads the root element. Put another way, documents that are ill-constructed with more than one root element will not read correctly. Also note that operator>> is somewhat slower than Parse, due to both implementation of the STL and limitations of TinyXML.
The world simply does not agree on whether white space should be kept, or condensed. For example, pretend the '_' is a space, and look at "Hello__world". HTML, and at least some XML parsers, will interpret this as "Helloworld". They condense white space. Some XML parsers do not, and will leave it as "Hello____world". (Remember to keep pretending the is a space.) Others suggest that Hello_world_ should become Helloworld.
It's an issue that hasn't been resolved to my satisfaction. TinyXML supports the first 2 approaches. Call TiXmlBase::SetCondenseWhiteSpace( bool ) to set the desired behavior. The default is to condense white space.
If you change the default, you should call TiXmlBase::SetCondenseWhiteSpace( bool ) before making any calls to Parse XML data, and I don't recommend changing it after it has been set.
Where browsing an XML document in a robust way, it is important to check for null returns from method calls. An error safe implementation can generate a lot of code like:
@verbatim TiXmlElement root = document.FirstChildElement( "Document" ); if ( root ) { TiXmlElement element = root->FirstChildElement( "Element" ); if ( element ) { TiXmlElement child = element->FirstChildElement( "Child" ); if ( child ) { TiXmlElement child2 = child->NextSiblingElement( "Child" ); if ( child2 ) { // Finally do something useful. @endverbatim
Handles have been introduced to clean this up. Using the TiXmlHandle class, the previous code reduces to:
@verbatim TiXmlHandle docHandle( &document ); TiXmlElement* child2 = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", 1 ).ToElement(); if ( child2 ) { // do something useful @endverbatim
Which is much easier to deal with. See TiXmlHandle for more information.
Being able to track nodes and attributes back to their origin location in source files can be very important for some applications. Additionally, knowing where parsing errors occured in the original source can be very time saving.
TinyXML can tracks the row and column origin of all nodes and attributes in a text file. The TiXmlBase::Row() and TiXmlBase::Column() methods return the origin of the node in the source text. The correct tabs can be configured in TiXmlDocument::SetTabSize().
To Compile and Run xmltest:
A Linux Makefile and a Windows Visual C++ .dsw file is provided. Simply compile and run. It will write the file demotest.xml to your disk and generate output on the screen. It also tests walking the DOM by printing out the number of nodes found using different techniques.
The Linux makefile is very generic and runs on many systems - it is currently tested on mingw and MacOSX. You do not need to run 'make depend'. The dependecies have been hard coded.
At the top of the makefile you can set:
PROFILE, DEBUG, and TINYXML_USE_STL. Details (such that they are) are in the makefile.
In the tinyxml directory, type "make clean" then "make". The executable file 'xmltest' will be created.
Add tinyxml.cpp, tinyxml.h, tinyxmlerror.cpp, tinyxmlparser.cpp, tinystr.cpp, and tinystr.h to your project or make file. That's it! It should compile on any reasonably compliant C++ system. You do not need to enable exceptions or RTTI for TinyXML.
An example is probably the best way to go. Take: @verbatim <?xml version="1.0" standalone=no>
<ToDo>
<Item priority="1"> Go to the <bold>Toy store!</bold></Item>
<Item priority="2"> Do bills</Item>
</ToDo>@endverbatim
Its not much of a To Do list, but it will do. To read this file (say "demo.xml") you would create a document, and parse it in: @verbatim TiXmlDocument doc( "demo.xml" ); doc.LoadFile(); @endverbatim
And its ready to go. Now lets look at some lines and how they relate to the DOM.
@verbatim <?xml version="1.0" standalone=no> @endverbatim
The first line is a declaration, and gets turned into the
TiXmlDeclaration class. It will be the first child of the
document node.
This is the only directive/special tag parsed by by TinyXML.
Generally directive tags are stored in TiXmlUnknown so the
commands wont be lost when it is saved back to disk.@verbatim
@endverbatim
A comment. Will become a TiXmlComment object.@verbatim