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| author | arseny.kapoulkine <arseny.kapoulkine@99668b35-9821-0410-8761-19e4c4f06640> | 2010-07-11 16:27:23 +0000 |
|---|---|---|
| committer | arseny.kapoulkine <arseny.kapoulkine@99668b35-9821-0410-8761-19e4c4f06640> | 2010-07-11 16:27:23 +0000 |
| commit | f9a2dec792d9a52e1b9004793cfca9b0a463049a (patch) | |
| tree | 4a5cf5ded896dd3ea485e01d0c41e2b94b973385 /docs/manual/loading.html | |
| parent | 468399c2eb1a9828310b11caf0c720785fd9c604 (diff) | |
docs: Added generated HTML documentation
git-svn-id: http://pugixml.googlecode.com/svn/trunk@596 99668b35-9821-0410-8761-19e4c4f06640
Diffstat (limited to 'docs/manual/loading.html')
| -rw-r--r-- | docs/manual/loading.html | 840 |
1 files changed, 840 insertions, 0 deletions
diff --git a/docs/manual/loading.html b/docs/manual/loading.html new file mode 100644 index 0000000..a3c1515 --- /dev/null +++ b/docs/manual/loading.html @@ -0,0 +1,840 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>Loading document</title> +<link rel="stylesheet" href="../pugixml.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> +<link rel="home" href="../manual.html" title="pugixml 0.9"> +<link rel="up" href="../manual.html" title="pugixml 0.9"> +<link rel="prev" href="dom.html" title="Document object model"> +<link rel="next" href="access.html" title="Accessing document data"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> +<table width="100%"><tr> +<td>pugixml 0.9 manual | + <a href="../manual.html">Overview</a> | + <a href="install.html">Installation</a> | + Document: + <a href="dom.html">Object model</a> · <b>Loading</b> · <a href="access.html">Accessing</a> · <a href="modify.html">Modifying</a> · <a href="saving.html">Saving</a> | + <a href="xpath.html">XPath</a> | + <a href="apiref.html">API Reference</a> | + <a href="toc.html">Table of Contents</a> +</td> +<td width="*" align="right"><div class="spirit-nav"> +<a accesskey="p" href="dom.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../manual.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../manual.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="access.html"><img src="../images/next.png" alt="Next"></a> +</div></td> +</tr></table> +<hr> +<div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="manual.loading"></a><a class="link" href="loading.html" title="Loading document"> Loading document</a> +</h2></div></div></div> +<div class="toc"><dl> +<dt><span class="section"><a href="loading.html#manual.loading.file"> Loading document from file</a></span></dt> +<dt><span class="section"><a href="loading.html#manual.loading.memory"> Loading document from memory</a></span></dt> +<dt><span class="section"><a href="loading.html#manual.loading.stream"> Loading document from C++ IOstreams</a></span></dt> +<dt><span class="section"><a href="loading.html#manual.loading.errors"> Handling parsing errors</a></span></dt> +<dt><span class="section"><a href="loading.html#manual.loading.options"> Parsing options</a></span></dt> +<dt><span class="section"><a href="loading.html#manual.loading.encoding"> Encodings</a></span></dt> +<dt><span class="section"><a href="loading.html#manual.loading.w3c"> Conformance to W3C specification</a></span></dt> +</dl></div> +<p> + pugixml provides several functions for loading XML data from various places + - files, C++ iostreams, memory buffers. All functions use an extremely fast + non-validating parser. This parser is not fully W3C conformant - it can load + any valid XML document, but does not perform some well-formedness checks. While + considerable effort is made to reject invalid XML documents, some validation + is not performed because of performance reasons. Also some XML transformations + (i.e. EOL handling or attribute value normalization) can impact parsing speed + and thus can be disabled. However for vast majority of XML documents there + is no performance difference between different parsing options. Parsing options + also control whether certain XML nodes are parsed; see <a class="xref" href="loading.html#manual.loading.options" title="Parsing options"> Parsing options</a> for + more information. + </p> +<p> + XML data is always converted to internal character format (see <a class="xref" href="dom.html#manual.dom.unicode" title="Unicode interface"> Unicode interface</a>) + before parsing. pugixml supports all popular Unicode encodings (UTF-8, UTF-16 + (big and little endian), UTF-32 (big and little endian); UCS-2 is naturally + supported since it's a strict subset of UTF-16) and handles all encoding conversions + automatically. Unless explicit encoding is specified, loading functions perform + automatic encoding detection based on first few characters of XML data, so + in almost all cases you do not have to specify document encoding. Encoding + conversion is described in more detail in <a class="xref" href="loading.html#manual.loading.encoding" title="Encodings"> Encodings</a>. + </p> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.loading.file"></a><a class="link" href="loading.html#manual.loading.file" title="Loading document from file"> Loading document from file</a> +</h3></div></div></div> +<a name="xml_document::load_file"></a><p> + The most common source of XML data is files; pugixml provides a separate + function for loading XML document from file: + </p> +<pre class="programlisting"><span class="identifier">xml_parse_result</span> <span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">load_file</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">path</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">options</span> <span class="special">=</span> <span class="identifier">parse_default</span><span class="special">,</span> <span class="identifier">xml_encoding</span> <span class="identifier">encoding</span> <span class="special">=</span> <span class="identifier">encoding_auto</span><span class="special">);</span> +</pre> +<p> + This function accepts file path as its first argument, and also two optional + arguments, which specify parsing options (see <a class="xref" href="loading.html#manual.loading.options" title="Parsing options"> Parsing options</a>) and + input data encoding (see <a class="xref" href="loading.html#manual.loading.encoding" title="Encodings"> Encodings</a>). The path has the target + operating system format, so it can be a relative or absolute one, it should + have the delimiters of target system, it should have the exact case if target + file system is case-sensitive, etc. File path is passed to system file opening + function as is. + </p> +<p> + <code class="computeroutput"><span class="identifier">load_file</span></code> destroys the existing + document tree and then tries to load the new tree from the specified file. + The result of the operation is returned in an <code class="computeroutput"><span class="identifier">xml_parse_result</span></code> + object; this object contains the operation status, and the related information + (i.e. last successfully parsed position in the input file, if parsing fails). + See <a class="xref" href="loading.html#manual.loading.errors" title="Handling parsing errors"> Handling parsing errors</a> for error handling details. + </p> +<div class="note"><table border="0" summary="Note"> +<tr> +<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../images/note.png"></td> +<th align="left">Note</th> +</tr> +<tr><td align="left" valign="top"><p> + As of version 0.9, there is no function for loading XML document from wide + character path. Unfortunately, there is no portable way to do this; the + version 1.0 will provide such function only for platforms with the corresponding + functionality. You can use stream-loading functions as a workaround if + your STL implementation can open file streams via <code class="computeroutput"><span class="keyword">wchar_t</span></code> + paths. + </p></td></tr> +</table></div> +<p> + This is an example of loading XML document from file (<a href="../samples/load_file.cpp" target="_top">samples/load_file.cpp</a>): + </p> +<p> + +</p> +<pre class="programlisting"><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_document</span> <span class="identifier">doc</span><span class="special">;</span> + +<span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_parse_result</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">load_file</span><span class="special">(</span><span class="string">"tree.xml"</span><span class="special">);</span> + +<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Load result: "</span> <span class="special"><<</span> <span class="identifier">result</span><span class="special">.</span><span class="identifier">description</span><span class="special">()</span> <span class="special"><<</span> <span class="string">", mesh name: "</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">child</span><span class="special">(</span><span class="string">"mesh"</span><span class="special">).</span><span class="identifier">attribute</span><span class="special">(</span><span class="string">"name"</span><span class="special">).</span><span class="identifier">value</span><span class="special">()</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> +</pre> +<p> + </p> +</div> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.loading.memory"></a><a class="link" href="loading.html#manual.loading.memory" title="Loading document from memory"> Loading document from memory</a> +</h3></div></div></div> +<a name="xml_document::load_buffer"></a><a name="xml_document::load_buffer_inplace"></a><a name="xml_document::load_buffer_inplace_own"></a><p> + Sometimes XML data should be loaded from some other source than file, i.e. + HTTP URL; also you may want to load XML data from file using non-standard + functions, i.e. to use your virtual file system facilities or to load XML + from gzip-compressed files. All these scenarios require loading document + from memory. First you should prepare a contiguous memory block with all + XML data; then you have to invoke one of buffer loading functions. These + functions will handle the necessary encoding conversions, if any, and then + will parse the data into the corresponding XML tree. There are several buffer + loading functions, which differ in the behavior and thus in performance/memory + usage: + </p> +<pre class="programlisting"><span class="identifier">xml_parse_result</span> <span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">load_buffer</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">void</span><span class="special">*</span> <span class="identifier">contents</span><span class="special">,</span> <span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">options</span> <span class="special">=</span> <span class="identifier">parse_default</span><span class="special">,</span> <span class="identifier">xml_encoding</span> <span class="identifier">encoding</span> <span class="special">=</span> <span class="identifier">encoding_auto</span><span class="special">);</span> +<span class="identifier">xml_parse_result</span> <span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">load_buffer_inplace</span><span class="special">(</span><span class="keyword">void</span><span class="special">*</span> <span class="identifier">contents</span><span class="special">,</span> <span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">options</span> <span class="special">=</span> <span class="identifier">parse_default</span><span class="special">,</span> <span class="identifier">xml_encoding</span> <span class="identifier">encoding</span> <span class="special">=</span> <span class="identifier">encoding_auto</span><span class="special">);</span> +<span class="identifier">xml_parse_result</span> <span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">load_buffer_inplace_own</span><span class="special">(</span><span class="keyword">void</span><span class="special">*</span> <span class="identifier">contents</span><span class="special">,</span> <span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">options</span> <span class="special">=</span> <span class="identifier">parse_default</span><span class="special">,</span> <span class="identifier">xml_encoding</span> <span class="identifier">encoding</span> <span class="special">=</span> <span class="identifier">encoding_auto</span><span class="special">);</span> +</pre> +<p> + All functions accept the buffer which is represented by a pointer to XML + data, <code class="computeroutput"><span class="identifier">contents</span></code>, and data + size in bytes. Also there are two optional arguments, which specify parsing + options (see <a class="xref" href="loading.html#manual.loading.options" title="Parsing options"> Parsing options</a>) and input data encoding (see <a class="xref" href="loading.html#manual.loading.encoding" title="Encodings"> Encodings</a>). + The buffer does not have to be zero-terminated. + </p> +<p> + <code class="computeroutput"><span class="identifier">load_buffer</span></code> function works + with immutable buffer - it does not ever modify the buffer. Because of this + restriction it has to create a private buffer and copy XML data to it before + parsing (applying encoding conversions if necessary). This copy operation + carries a performance penalty, so inplace functions are provided - <code class="computeroutput"><span class="identifier">load_buffer_inplace</span></code> and <code class="computeroutput"><span class="identifier">load_buffer_inplace_own</span></code> + store the document data in the buffer, modifying it in the process. In order + for the document to stay valid, you have to make sure that the buffer's lifetime + exceeds that of the tree if you're using inplace functions. In addition to + that, <code class="computeroutput"><span class="identifier">load_buffer_inplace</span></code> + does not assume ownership of the buffer, so you'll have to destroy it yourself; + <code class="computeroutput"><span class="identifier">load_buffer_inplace_own</span></code> assumes + ownership of the buffer and destroys it once it is not needed. This means + that if you're using <code class="computeroutput"><span class="identifier">load_buffer_inplace_own</span></code>, + you have to allocate memory with pugixml allocation function (you can get + it via <a class="link" href="dom.html#get_memory_allocation_function">get_memory_allocation_function</a>). + </p> +<p> + The best way from the performance/memory point of view is to load document + using <code class="computeroutput"><span class="identifier">load_buffer_inplace_own</span></code>; + this function has maximum control of the buffer with XML data so it is able + to avoid redundant copies and reduce peak memory usage while parsing. This + is the recommended function if you have to load the document from memory + and performance is critical. + </p> +<a name="xml_document::load_string"></a><p> + There is also a simple helper function for cases when you want to load the + XML document from null-terminated character string: + </p> +<pre class="programlisting"><span class="identifier">xml_parse_result</span> <span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">load</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">contents</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">options</span> <span class="special">=</span> <span class="identifier">parse_default</span><span class="special">);</span> +</pre> +<p> + It is equivalent to calling <code class="computeroutput"><span class="identifier">load_buffer</span></code> + with <code class="computeroutput"><span class="identifier">size</span> <span class="special">=</span> + <span class="identifier">strlen</span><span class="special">(</span><span class="identifier">contents</span><span class="special">)</span></code>. + This function assumes native encoding for input data, so it does not do any + encoding conversion. In general, this function is fine for loading small + documents from string literals, but has more overhead and less functionality + than buffer loading functions. + </p> +<p> + This is an example of loading XML document from memory using different functions + (<a href="../samples/load_memory.cpp" target="_top">samples/load_memory.cpp</a>): + </p> +<p> + +</p> +<pre class="programlisting"><span class="keyword">const</span> <span class="keyword">char</span> <span class="identifier">source</span><span class="special">[]</span> <span class="special">=</span> <span class="string">"<mesh name='sphere'><bounds>0 0 1 1</bounds></mesh>"</span><span class="special">;</span> +<span class="identifier">size_t</span> <span class="identifier">size</span> <span class="special">=</span> <span class="keyword">sizeof</span><span class="special">(</span><span class="identifier">source</span><span class="special">);</span> +</pre> +<p> + </p> +<p> + +</p> +<pre class="programlisting"><span class="comment">// You can use load_buffer to load document from immutable memory block: +</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_parse_result</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">load_buffer</span><span class="special">(</span><span class="identifier">source</span><span class="special">,</span> <span class="identifier">size</span><span class="special">);</span> +</pre> +<p> + </p> +<p> + +</p> +<pre class="programlisting"><span class="comment">// You can use load_buffer_inplace to load document from mutable memory block; the block's lifetime must exceed that of document +</span><span class="keyword">char</span><span class="special">*</span> <span class="identifier">buffer</span> <span class="special">=</span> <span class="keyword">new</span> <span class="keyword">char</span><span class="special">[</span><span class="identifier">size</span><span class="special">];</span> +<span class="identifier">memcpy</span><span class="special">(</span><span class="identifier">buffer</span><span class="special">,</span> <span class="identifier">source</span><span class="special">,</span> <span class="identifier">size</span><span class="special">);</span> + +<span class="comment">// The block can be allocated by any method; the block is modified during parsing +</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_parse_result</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">load_buffer_inplace</span><span class="special">(</span><span class="identifier">buffer</span><span class="special">,</span> <span class="identifier">size</span><span class="special">);</span> + +<span class="comment">// You have to destroy the block yourself after the document is no longer used +</span><span class="keyword">delete</span><span class="special">[]</span> <span class="identifier">buffer</span><span class="special">;</span> +</pre> +<p> + </p> +<p> + +</p> +<pre class="programlisting"><span class="comment">// You can use load_buffer_inplace_own to load document from mutable memory block and to pass the ownership of this block +</span><span class="comment">// The block has to be allocated via pugixml allocation function - using i.e. operator new here is incorrect +</span><span class="keyword">char</span><span class="special">*</span> <span class="identifier">buffer</span> <span class="special">=</span> <span class="keyword">static_cast</span><span class="special"><</span><span class="keyword">char</span><span class="special">*>(</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">get_memory_allocation_function</span><span class="special">()(</span><span class="identifier">size</span><span class="special">));</span> +<span class="identifier">memcpy</span><span class="special">(</span><span class="identifier">buffer</span><span class="special">,</span> <span class="identifier">source</span><span class="special">,</span> <span class="identifier">size</span><span class="special">);</span> + +<span class="comment">// The block will be deleted by the document +</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_parse_result</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">load_buffer_inplace_own</span><span class="special">(</span><span class="identifier">buffer</span><span class="special">,</span> <span class="identifier">size</span><span class="special">);</span> +</pre> +<p> + </p> +<p> + +</p> +<pre class="programlisting"><span class="comment">// You can use load to load document from null-terminated strings, for example literals: +</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_parse_result</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">load</span><span class="special">(</span><span class="string">"<mesh name='sphere'><bounds>0 0 1 1</bounds></mesh>"</span><span class="special">);</span> +</pre> +<p> + </p> +</div> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.loading.stream"></a><a class="link" href="loading.html#manual.loading.stream" title="Loading document from C++ IOstreams"> Loading document from C++ IOstreams</a> +</h3></div></div></div> +<a name="xml_document::load_stream"></a><p> + For additional interoperability pugixml provides functions for loading document + from any object which implements C++ <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">istream</span></code> + interface. This allows you to load documents from any standard C++ stream + (i.e. file stream) or any third-party compliant implementation (i.e. Boost + Iostreams). There are two functions, one works with narrow character streams, + another handles wide character ones: + </p> +<pre class="programlisting"><span class="identifier">xml_parse_result</span> <span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">load</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">istream</span><span class="special">&</span> <span class="identifier">stream</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">options</span> <span class="special">=</span> <span class="identifier">parse_default</span><span class="special">,</span> <span class="identifier">xml_encoding</span> <span class="identifier">encoding</span> <span class="special">=</span> <span class="identifier">encoding_auto</span><span class="special">);</span> +<span class="identifier">xml_parse_result</span> <span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">load</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">wistream</span><span class="special">&</span> <span class="identifier">stream</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">options</span> <span class="special">=</span> <span class="identifier">parse_default</span><span class="special">);</span> +</pre> +<p> + <code class="computeroutput"><span class="identifier">load</span></code> with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">istream</span></code> + argument loads the document from stream from the current read position to + the end, treating the stream contents as a byte stream of the specified encoding + (with encoding autodetection as necessary). Thus calling <code class="computeroutput"><span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">load</span></code> + on an opened <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">ifstream</span></code> object is equivalent to calling + <code class="computeroutput"><span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">load_file</span></code>. + </p> +<p> + <code class="computeroutput"><span class="identifier">load</span></code> with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">wstream</span></code> + argument treats the stream contents as a wide character stream (encoding + is always <code class="computeroutput"><span class="identifier">encoding_wchar</span></code>). + Because of this, using <code class="computeroutput"><span class="identifier">load</span></code> + with wide character streams requires careful (usually platform-specific) + stream setup (i.e. using the <code class="computeroutput"><span class="identifier">imbue</span></code> + function). Generally use of wide streams is discouraged, however it provides + you the ability to load documents from non-Unicode encodings, i.e. you can + load Shift-JIS encoded data if you set the correct locale. + </p> +<p> + This is a simple example of loading XML document from file using streams + (<a href="../samples/load_stream.cpp" target="_top">samples/load_stream.cpp</a>); read + the sample code for more complex examples involving wide streams and locales: + </p> +<p> + +</p> +<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">ifstream</span> <span class="identifier">stream</span><span class="special">(</span><span class="string">"weekly-utf-8.xml"</span><span class="special">);</span> +<span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_parse_result</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">load</span><span class="special">(</span><span class="identifier">stream</span><span class="special">);</span> +</pre> +<p> + </p> +<p> + Stream loading requires working seek/tell functions and therefore may fail + when used with some stream implementations like gzstream. + </p> +</div> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.loading.errors"></a><a class="link" href="loading.html#manual.loading.errors" title="Handling parsing errors"> Handling parsing errors</a> +</h3></div></div></div> +<a name="xml_parse_result"></a><p> + All document loading functions return the parsing result via <code class="computeroutput"><span class="identifier">xml_parse_result</span></code> object. It contains parsing + status, the offset of last successfully parsed character from the beginning + of the source stream, and the encoding of the source stream: + </p> +<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">xml_parse_result</span> +<span class="special">{</span> + <span class="identifier">xml_parse_status</span> <span class="identifier">status</span><span class="special">;</span> + <span class="identifier">ptrdiff_t</span> <span class="identifier">offset</span><span class="special">;</span> + <span class="identifier">xml_encoding</span> <span class="identifier">encoding</span><span class="special">;</span> + + <span class="keyword">operator</span> <span class="keyword">bool</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span> + <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">description</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span> +<span class="special">};</span> +</pre> +<a name="xml_parse_status"></a><a name="xml_parse_result::status"></a><p> + Parsing status is represented as the <code class="computeroutput"><span class="identifier">xml_parse_status</span></code> + enumeration and can be one of the following: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + <a name="status_ok"></a><code class="literal">status_ok</code> means that no error was encountered + during parsing; the source stream represents the valid XML document which + was fully parsed and converted to a tree. <br><br> + + </li> +<li class="listitem"> + <a name="status_file_not_found"></a><code class="literal">status_file_not_found</code> is only + returned by <code class="computeroutput"><span class="identifier">load_file</span></code> + function and means that file could not be opened. + </li> +<li class="listitem"> + <a name="status_io_error"></a><code class="literal">status_io_error</code> is returned by <code class="computeroutput"><span class="identifier">load_file</span></code> function and by <code class="computeroutput"><span class="identifier">load</span></code> functions with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">istream</span></code>/<code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">wstream</span></code> arguments; it means that some + I/O error has occured during reading the file/stream. + </li> +<li class="listitem"> + <a name="status_out_of_memory"></a><code class="literal">status_out_of_memory</code> means that + there was not enough memory during some allocation; any allocation failure + during parsing results in this error. + </li> +<li class="listitem"> + <a name="status_internal_error"></a><code class="literal">status_internal_error</code> means that + something went horribly wrong; currently this error does not occur <br><br> + + </li> +<li class="listitem"> + <a name="status_unrecognized_tag"></a><code class="literal">status_unrecognized_tag</code> means + that parsing stopped due to a tag with either an empty name or a name + which starts with incorrect character, such as <code class="literal">#</code>. + </li> +<li class="listitem"> + <a name="status_bad_pi"></a><code class="literal">status_bad_pi</code> means that parsing stopped + due to incorrect document declaration/processing instruction + </li> +<li class="listitem"> + <a name="status_bad_comment"></a><code class="literal">status_bad_comment</code>, <a name="status_bad_cdata"></a><code class="literal">status_bad_cdata</code>, + <a name="status_bad_doctype"></a><code class="literal">status_bad_doctype</code> and <a name="status_bad_pcdata"></a><code class="literal">status_bad_pcdata</code> + mean that parsing stopped due to the invalid construct of the respective + type + </li> +<li class="listitem"> + <a name="status_bad_start_element"></a><code class="literal">status_bad_start_element</code> means + that parsing stopped because starting tag either had no closing <code class="computeroutput"><span class="special">></span></code> symbol or contained some incorrect + symbol + </li> +<li class="listitem"> + <a name="status_bad_attribute"></a><code class="literal">status_bad_attribute</code> means that + parsing stopped because there was an incorrect attribute, such as an + attribute without value or with value that is not quoted (note that + <code class="computeroutput"><span class="special"><</span><span class="identifier">node</span> + <span class="identifier">attr</span><span class="special">=</span><span class="number">1</span><span class="special">></span></code> is + incorrect in XML) + </li> +<li class="listitem"> + <a name="status_bad_end_element"></a><code class="literal">status_bad_end_element</code> means + that parsing stopped because ending tag had incorrect syntax (i.e. extra + non-whitespace symbols between tag name and <code class="computeroutput"><span class="special">></span></code>) + </li> +<li class="listitem"> + <a name="status_end_element_mismatch"></a><code class="literal">status_end_element_mismatch</code> + means that parsing stopped because the closing tag did not match the + opening one (i.e. <code class="computeroutput"><span class="special"><</span><span class="identifier">node</span><span class="special">></</span><span class="identifier">nedo</span><span class="special">></span></code>) or because some tag was not closed + at all + </li> +</ul></div> +<a name="xml_parse_result::description"></a><p> + <code class="computeroutput"><span class="identifier">description</span><span class="special">()</span></code> + member function can be used to convert parsing status to a string; the returned + message is always in English, so you'll have to write your own function if + you need a localized string. However please note that the exact messages + returned by <code class="computeroutput"><span class="identifier">description</span><span class="special">()</span></code> + function may change from version to version, so any complex status handling + should be based on <code class="computeroutput"><span class="identifier">status</span></code> + value. + </p> +<p> + If parsing failed because the source data was not a valid XML, the resulting + tree is not destroyed - despite the fact that load function returns error, + you can use the part of the tree that was successfully parsed. Obviously, + the last element may have an unexpected name/value; for example, if the attribute + value does not end with the necessary quotation mark, like in <code class="literal"><node + attr="value>some data</node></code> example, the value of + attribute <code class="computeroutput"><span class="identifier">attr</span></code> will contain + the string <code class="computeroutput"><span class="identifier">value</span><span class="special">></span><span class="identifier">some</span> <span class="identifier">data</span><span class="special"></</span><span class="identifier">node</span><span class="special">></span></code>. + </p> +<a name="xml_parse_result::offset"></a><p> + In addition to the status code, parsing result has an <code class="computeroutput"><span class="identifier">offset</span></code> + member, which contains the offset of last successfully parsed character if + parsing failed because of an error in source data; otherwise <code class="computeroutput"><span class="identifier">offset</span></code> is 0. For parsing efficiency reasons, + pugixml does not track the current line during parsing; this offset is in + units of <code class="computeroutput"><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">char_t</span></code> (bytes for character mode, wide + characters for wide character mode). Many text editors support 'Go To Position' + feature - you can use it to locate the exact error position. Alternatively, + if you're loading the document from memory, you can display the error chunk + along with the error description (see the example code below). + </p> +<div class="caution"><table border="0" summary="Caution"> +<tr> +<td rowspan="2" align="center" valign="top" width="25"><img alt="[Caution]" src="../images/caution.png"></td> +<th align="left">Caution</th> +</tr> +<tr><td align="left" valign="top"><p> + Offset is calculated in the XML buffer in native encoding; if encoding + conversion is performed during parsing, offset can not be used to reliably + track the error position. + </p></td></tr> +</table></div> +<a name="xml_parse_result::encoding"></a><p> + Parsing result also has an <code class="computeroutput"><span class="identifier">encoding</span></code> + member, which can be used to check that the source data encoding was correctly + guessed. It is equal to the exact encoding used during parsing (i.e. with + the exact endianness); see <a class="xref" href="loading.html#manual.loading.encoding" title="Encodings"> Encodings</a> for more information. + </p> +<a name="xml_parse_result::bool"></a><p> + Parsing result object can be implicitly converted to <code class="computeroutput"><span class="keyword">bool</span></code>; + if you do not want to handle parsing errors thoroughly, you can just check + the return value of load functions as if it was a <code class="computeroutput"><span class="keyword">bool</span></code>: + <code class="computeroutput"><span class="keyword">if</span> <span class="special">(</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">load_file</span><span class="special">(</span><span class="string">"file.xml"</span><span class="special">))</span> <span class="special">{</span> <span class="special">...</span> + <span class="special">}</span> <span class="keyword">else</span> <span class="special">{</span> <span class="special">...</span> <span class="special">}</span></code>. + </p> +<p> + This is an example of handling loading errors (<a href="../samples/load_error_handling.cpp" target="_top">samples/load_error_handling.cpp</a>): + </p> +<p> + +</p> +<pre class="programlisting"><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_document</span> <span class="identifier">doc</span><span class="special">;</span> +<span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_parse_result</span> <span class="identifier">result</span> <span class="special">=</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">load</span><span class="special">(</span><span class="identifier">source</span><span class="special">);</span> + +<span class="keyword">if</span> <span class="special">(</span><span class="identifier">result</span><span class="special">)</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"XML ["</span> <span class="special"><<</span> <span class="identifier">source</span> <span class="special"><<</span> <span class="string">"] parsed without errors, attr value: ["</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">child</span><span class="special">(</span><span class="string">"node"</span><span class="special">).</span><span class="identifier">attribute</span><span class="special">(</span><span class="string">"attr"</span><span class="special">).</span><span class="identifier">value</span><span class="special">()</span> <span class="special"><<</span> <span class="string">"]\n\n"</span><span class="special">;</span> +<span class="keyword">else</span> +<span class="special">{</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"XML ["</span> <span class="special"><<</span> <span class="identifier">source</span> <span class="special"><<</span> <span class="string">"] parsed with errors, attr value: ["</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">child</span><span class="special">(</span><span class="string">"node"</span><span class="special">).</span><span class="identifier">attribute</span><span class="special">(</span><span class="string">"attr"</span><span class="special">).</span><span class="identifier">value</span><span class="special">()</span> <span class="special"><<</span> <span class="string">"]\n"</span><span class="special">;</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Error description: "</span> <span class="special"><<</span> <span class="identifier">result</span><span class="special">.</span><span class="identifier">description</span><span class="special">()</span> <span class="special"><<</span> <span class="string">"\n"</span><span class="special">;</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Error offset: "</span> <span class="special"><<</span> <span class="identifier">result</span><span class="special">.</span><span class="identifier">offset</span> <span class="special"><<</span> <span class="string">" (error at [..."</span> <span class="special"><<</span> <span class="special">(</span><span class="identifier">source</span> <span class="special">+</span> <span class="identifier">result</span><span class="special">.</span><span class="identifier">offset</span><span class="special">)</span> <span class="special"><<</span> <span class="string">"]\n\n"</span><span class="special">;</span> +<span class="special">}</span> +</pre> +<p> + </p> +</div> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.loading.options"></a><a class="link" href="loading.html#manual.loading.options" title="Parsing options"> Parsing options</a> +</h3></div></div></div> +<p> + All document loading functions accept the optional parameter <code class="computeroutput"><span class="identifier">options</span></code>. This is a bitmask that customizes + the parsing process: you can select the node types that are parsed and various + transformations that are performed with the XML text. Disabling certain transformations + can improve parsing performance for some documents; however, the code for + all transformations is very well optimized, and thus the majority of documents + won't get any performance benefit. As a rule of thumb, only modify parsing + flags if you want to get some nodes in the document that are excluded by + default (i.e. declaration or comment nodes). + </p> +<div class="note"><table border="0" summary="Note"> +<tr> +<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../images/note.png"></td> +<th align="left">Note</th> +</tr> +<tr><td align="left" valign="top"><p> + You should use the usual bitwise arithmetics to manipulate the bitmask: + to enable a flag, use <code class="computeroutput"><span class="identifier">mask</span> <span class="special">|</span> <span class="identifier">flag</span></code>; + to disable a flag, use <code class="computeroutput"><span class="identifier">mask</span> <span class="special">&</span> <span class="special">~</span><span class="identifier">flag</span></code>. + </p></td></tr> +</table></div> +<p> + These flags control the resulting tree contents: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + <a name="parse_declaration"></a><code class="literal">parse_declaration</code> determines if XML + document declaration (node with type <a class="link" href="dom.html#node_declaration">node_declaration</a>) + are to be put in DOM tree. If this flag is off, it is not put in the + tree, but is still parsed and checked for correctness. This flag is + <span class="bold"><strong>off</strong></span> by default. <br><br> + + </li> +<li class="listitem"> + <a name="parse_pi"></a><code class="literal">parse_pi</code> determines if processing instructions + (nodes with type <a class="link" href="dom.html#node_pi">node_pi</a>) are to be put + in DOM tree. If this flag is off, they are not put in the tree, but are + still parsed and checked for correctness. Note that <code class="computeroutput"><span class="special"><?</span><span class="identifier">xml</span> <span class="special">...?></span></code> + (document declaration) is not considered to be a PI. This flag is <span class="bold"><strong>off</strong></span> by default. <br><br> + + </li> +<li class="listitem"> + <a name="parse_comments"></a><code class="literal">parse_comments</code> determines if comments + (nodes with type <a class="link" href="dom.html#node_comment">node_comment</a>) are + to be put in DOM tree. If this flag is off, they are not put in the tree, + but are still parsed and checked for correctness. This flag is <span class="bold"><strong>off</strong></span> by default. <br><br> + + </li> +<li class="listitem"> + <a name="parse_cdata"></a><code class="literal">parse_cdata</code> determines if CDATA sections + (nodes with type <a class="link" href="dom.html#node_cdata">node_cdata</a>) are to + be put in DOM tree. If this flag is off, they are not put in the tree, + but are still parsed and checked for correctness. This flag is <span class="bold"><strong>on</strong></span> by default. <br><br> + + </li> +<li class="listitem"> + <a name="parse_ws_pcdata"></a><code class="literal">parse_ws_pcdata</code> determines if PCDATA + nodes (nodes with type <a class="link" href="dom.html#node_pcdata">node_pcdata</a>) + that consist only of whitespace characters are to be put in DOM tree. + Often whitespace-only data is not significant for the application, and + the cost of allocating and storing such nodes (both memory and speed-wise) + can be significant. For example, after parsing XML string <code class="computeroutput"><span class="special"><</span><span class="identifier">node</span><span class="special">></span> <span class="special"><</span><span class="identifier">a</span><span class="special">/></span> <span class="special"></</span><span class="identifier">node</span><span class="special">></span></code>, <code class="computeroutput"><span class="special"><</span><span class="identifier">node</span><span class="special">></span></code> + element will have three children when <code class="computeroutput"><span class="identifier">parse_ws_pcdata</span></code> + is set (child with type <code class="computeroutput"><span class="identifier">node_pcdata</span></code> + and value <code class="computeroutput"><span class="string">" "</span></code>, + child with type <code class="computeroutput"><span class="identifier">node_element</span></code> + and name <code class="computeroutput"><span class="string">"a"</span></code>, and + another child with type <code class="computeroutput"><span class="identifier">node_pcdata</span></code> + and value <code class="computeroutput"><span class="string">" "</span></code>), + and only one child when <code class="computeroutput"><span class="identifier">parse_ws_pcdata</span></code> + is not set. This flag is <span class="bold"><strong>off</strong></span> by default. + </li> +</ul></div> +<p> + These flags control the transformation of tree element contents: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + <a name="parse_escapes"></a><code class="literal">parse_escapes</code> determines if character + and entity references are to be expanded during the parsing process. + Character references have the form <code class="literal">&#...;</code> or + <code class="literal">&#x...;</code> (<code class="literal">...</code> is Unicode numeric + representation of character in either decimal (<code class="literal">&#...;</code>) + or hexadecimal (<code class="literal">&#x...;</code>) form), entity references + are <code class="literal">&lt;</code>, <code class="literal">&gt;</code>, <code class="literal">&amp;</code>, + <code class="literal">&apos;</code> and <code class="literal">&quot;</code> (note + that as pugixml does not handle DTD, the only allowed entities are predefined + ones). If character/entity reference can not be expanded, it is left + as is, so you can do additional processing later. Reference expansion + is performed in attribute values and PCDATA content. This flag is <span class="bold"><strong>on</strong></span> by default. <br><br> + + </li> +<li class="listitem"> + <a name="parse_eol"></a><code class="literal">parse_eol</code> determines if EOL handling (that + is, replacing sequences <code class="computeroutput"><span class="number">0x0d</span> <span class="number">0x0a</span></code> by a single <code class="computeroutput"><span class="number">0x0a</span></code> + character, and replacing all standalone <code class="computeroutput"><span class="number">0x0d</span></code> + characters by <code class="computeroutput"><span class="number">0x0a</span></code>) is to + be performed on input data (that is, comments contents, PCDATA/CDATA + contents and attribute values). This flag is <span class="bold"><strong>on</strong></span> + by default. <br><br> + + </li> +<li class="listitem"> + <a name="parse_wconv_attribute"></a><code class="literal">parse_wconv_attribute</code> determines + if attribute value normalization should be performed for all attributes. + This means, that whitespace characters (new line, tab and space) are + replaced with space (<code class="computeroutput"><span class="char">' '</span></code>). + New line characters are always treated as if <code class="computeroutput"><span class="identifier">parse_eol</span></code> + is set, i.e. <code class="computeroutput"><span class="special">\</span><span class="identifier">r</span><span class="special">\</span><span class="identifier">n</span></code> + is converted to single space. This flag is <span class="bold"><strong>on</strong></span> + by default. <br><br> + + </li> +<li class="listitem"> + <a name="parse_wnorm_attribute"></a><code class="literal">parse_wnorm_attribute</code> determines + if extended attribute value normalization should be performed for all + attributes. This means, that after attribute values are normalized as + if <code class="computeroutput"><span class="identifier">parse_wconv_attribute</span></code> + was set, leading and trailing space characters are removed, and all sequences + of space characters are replaced by a single space character. The value + of <code class="computeroutput"><span class="identifier">parse_wconv_attribute</span></code> + has no effect if this flag is on. This flag is <span class="bold"><strong>off</strong></span> + by default. + </li> +</ul></div> +<div class="note"><table border="0" summary="Note"> +<tr> +<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../images/note.png"></td> +<th align="left">Note</th> +</tr> +<tr><td align="left" valign="top"><p> + <code class="computeroutput"><span class="identifier">parse_wconv_attribute</span></code> option + performs transformations that are required by W3C specification for attributes + that are declared as <code class="literal">CDATA</code>; <code class="computeroutput"><span class="identifier">parse_wnorm_attribute</span></code> + performs transformations required for <code class="literal">NMTOKENS</code> attributes. + In the absence of document type declaration all attributes behave as if + they are declared as <code class="literal">CDATA</code>, thus <code class="computeroutput"><span class="identifier">parse_wconv_attribute</span></code> + is the default option. + </p></td></tr> +</table></div> +<p> + Additionally there are two predefined option masks: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + <a name="parse_minimal"></a><code class="literal">parse_minimal</code> has all options turned + off. This option mask means that pugixml does not add declaration nodes, + PI nodes, CDATA sections and comments to the resulting tree and does + not perform any conversion for input data, so theoretically it is the + fastest mode. However, as discussed above, in practice <code class="computeroutput"><span class="identifier">parse_default</span></code> is usually equally fast. + <br><br> + + </li> +<li class="listitem"> + <a name="parse_default"></a><code class="literal">parse_default</code> is the default set of flags, + i.e. it has all options set to their default values. It includes parsing + CDATA sections (comments/PIs are not parsed), performing character and + entity reference expansion, replacing whitespace characters with spaces + in attribute values and performing EOL handling. Note, that PCDATA sections + consisting only of whitespace characters are not parsed (by default) + for performance reasons. + </li> +</ul></div> +<p> + This is an example of using different parsing options (<a href="../samples/load_options.cpp" target="_top">samples/load_options.cpp</a>): + </p> +<p> + +</p> +<pre class="programlisting"><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">source</span> <span class="special">=</span> <span class="string">"<!--comment--><node>&lt;</node>"</span><span class="special">;</span> + +<span class="comment">// Parsing with default options; note that comment node is not added to the tree, and entity reference &lt; is expanded +</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">load</span><span class="special">(</span><span class="identifier">source</span><span class="special">);</span> +<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"First node value: ["</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">first_child</span><span class="special">().</span><span class="identifier">value</span><span class="special">()</span> <span class="special"><<</span> <span class="string">"], node child value: ["</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">child_value</span><span class="special">(</span><span class="string">"node"</span><span class="special">)</span> <span class="special"><<</span> <span class="string">"]\n"</span><span class="special">;</span> + +<span class="comment">// Parsing with additional parse_comments option; comment node is now added to the tree +</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">load</span><span class="special">(</span><span class="identifier">source</span><span class="special">,</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">parse_default</span> <span class="special">|</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">parse_comments</span><span class="special">);</span> +<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"First node value: ["</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">first_child</span><span class="special">().</span><span class="identifier">value</span><span class="special">()</span> <span class="special"><<</span> <span class="string">"], node child value: ["</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">child_value</span><span class="special">(</span><span class="string">"node"</span><span class="special">)</span> <span class="special"><<</span> <span class="string">"]\n"</span><span class="special">;</span> + +<span class="comment">// Parsing with additional parse_comments option and without the (default) parse_escapes option; &lt; is not expanded +</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">load</span><span class="special">(</span><span class="identifier">source</span><span class="special">,</span> <span class="special">(</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">parse_default</span> <span class="special">|</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">parse_comments</span><span class="special">)</span> <span class="special">&</span> <span class="special">~</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">parse_escapes</span><span class="special">);</span> +<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"First node value: ["</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">first_child</span><span class="special">().</span><span class="identifier">value</span><span class="special">()</span> <span class="special"><<</span> <span class="string">"], node child value: ["</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">child_value</span><span class="special">(</span><span class="string">"node"</span><span class="special">)</span> <span class="special"><<</span> <span class="string">"]\n"</span><span class="special">;</span> + +<span class="comment">// Parsing with minimal option mask; comment node is not added to the tree, and &lt; is not expanded +</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">load</span><span class="special">(</span><span class="identifier">source</span><span class="special">,</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">parse_minimal</span><span class="special">);</span> +<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"First node value: ["</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">first_child</span><span class="special">().</span><span class="identifier">value</span><span class="special">()</span> <span class="special"><<</span> <span class="string">"], node child value: ["</span> <span class="special"><<</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">child_value</span><span class="special">(</span><span class="string">"node"</span><span class="special">)</span> <span class="special"><<</span> <span class="string">"]\n"</span><span class="special">;</span> +</pre> +<p> + </p> +</div> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.loading.encoding"></a><a class="link" href="loading.html#manual.loading.encoding" title="Encodings"> Encodings</a> +</h3></div></div></div> +<a name="xml_encoding"></a><p> + pugixml supports all popular Unicode encodings (UTF-8, UTF-16 (big and little + endian), UTF-32 (big and little endian); UCS-2 is naturally supported since + it's a strict subset of UTF-16) and handles all encoding conversions. Most + loading functions accept the optional parameter <code class="computeroutput"><span class="identifier">encoding</span></code>. + This is a value of enumeration type <code class="computeroutput"><span class="identifier">xml_encoding</span></code>, + that can have the following values: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + <a name="encoding_auto"></a><code class="literal">encoding_auto</code> means that pugixml will + try to guess the encoding based on source XML data. The algorithm is + a modified version of the one presented in Appendix F.1 of XML recommendation; + it tries to match the first few bytes of input data with the following + patterns in strict order: <br><br> + <div class="itemizedlist"><ul class="itemizedlist" type="circle"> +<li class="listitem"> + If first four bytes match UTF-32 BOM (Byte Order Mark), encoding + is assumed to be UTF-32 with the endianness equal to that of BOM; + </li> +<li class="listitem"> + If first two bytes match UTF-16 BOM, encoding is assumed to be + UTF-16 with the endianness equal to that of BOM; + </li> +<li class="listitem"> + If first three bytes match UTF-8 BOM, encoding is assumed to be + UTF-8; + </li> +<li class="listitem"> + If first four bytes match UTF-32 representation of <code class="literal"><</code>, + encoding is assumed to be UTF-32 with the corresponding endianness; + </li> +<li class="listitem"> + If first four bytes match UTF-16 representation of <code class="literal"><?</code>, + encoding is assumed to be UTF-16 with the corresponding endianness; + </li> +<li class="listitem"> + If first two bytes match UTF-16 representation of <code class="literal"><</code>, + encoding is assumed to be UTF-16 with the corresponding endianness + (this guess may yield incorrect result, but it's better than UTF-8); + </li> +<li class="listitem"> + Otherwise encoding is assumed to be UTF-8. <br><br> + + </li> +</ul></div> + </li> +<li class="listitem"> + <a name="encoding_utf8"></a><code class="literal">encoding_utf8</code> corresponds to UTF-8 encoding + as defined in Unicode standard; UTF-8 sequences with length equal to + 5 or 6 are not standard and are rejected. + </li> +<li class="listitem"> + <a name="encoding_utf16_le"></a><code class="literal">encoding_utf16_le</code> corresponds to + little-endian UTF-16 encoding as defined in Unicode standard; surrogate + pairs are supported. + </li> +<li class="listitem"> + <a name="encoding_utf16_be"></a><code class="literal">encoding_utf16_be</code> corresponds to + big-endian UTF-16 encoding as defined in Unicode standard; surrogate + pairs are supported. + </li> +<li class="listitem"> + <a name="encoding_utf16"></a><code class="literal">encoding_utf16</code> corresponds to UTF-16 + encoding as defined in Unicode standard; the endianness is assumed to + be that of target platform. + </li> +<li class="listitem"> + <a name="encoding_utf32_le"></a><code class="literal">encoding_utf32_le</code> corresponds to + little-endian UTF-32 encoding as defined in Unicode standard. + </li> +<li class="listitem"> + <a name="encoding_utf32_be"></a><code class="literal">encoding_utf32_be</code> corresponds to + big-endian UTF-32 encoding as defined in Unicode standard. + </li> +<li class="listitem"> + <a name="encoding_utf32"></a><code class="literal">encoding_utf32</code> corresponds to UTF-32 + encoding as defined in Unicode standard; the endianness is assumed to + be that of target platform. + </li> +<li class="listitem"> + <a name="encoding_wchar"></a><code class="literal">encoding_wchar</code> corresponds to the encoding + of <code class="computeroutput"><span class="keyword">wchar_t</span></code> type; it has + the same meaning as either <code class="computeroutput"><span class="identifier">encoding_utf16</span></code> + or <code class="computeroutput"><span class="identifier">encoding_utf32</span></code>, depending + on <code class="computeroutput"><span class="keyword">wchar_t</span></code> size. + </li> +</ul></div> +<p> + The algorithm used for <code class="computeroutput"><span class="identifier">encoding_auto</span></code> + correctly detects any supported Unicode encoding for all well-formed XML + documents (since they start with document declaration) and for all other + XML documents that start with <code class="literal"><</code>; if your XML document + does not start with <code class="literal"><</code> and has encoding that is different + from UTF-8, use the specific encoding. + </p> +<div class="note"><table border="0" summary="Note"> +<tr> +<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../images/note.png"></td> +<th align="left">Note</th> +</tr> +<tr><td align="left" valign="top"><p> + The current behavior for Unicode conversion is to skip all invalid UTF + sequences during conversion. This behavior should not be relied upon; moreover, + in case no encoding conversion is performed, the invalid sequences are + not removed, so you'll get them as is in node/attribute contents. + </p></td></tr> +</table></div> +</div> +<div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="manual.loading.w3c"></a><a class="link" href="loading.html#manual.loading.w3c" title="Conformance to W3C specification"> Conformance to W3C specification</a> +</h3></div></div></div> +<p> + pugixml is not fully W3C conformant - it can load any valid XML document, + but does not perform some well-formedness checks. While considerable effort + is made to reject invalid XML documents, some validation is not performed + because of performance reasons. + </p> +<p> + There is only one non-conformant behavior when dealing with valid XML documents: + pugixml does not use information supplied in document type declaration for + parsing. This means that entities declared in DOCTYPE are not expanded, and + all attribute/PCDATA values are always processed in a uniform way that depends + only on parsing options. + </p> +<p> + As for rejecting invalid XML documents, there are a number of incompatibilities + with W3C specification, including: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + Multiple attributes of the same node can have equal names. + </li> +<li class="listitem"> + All non-ASCII characters are treated in the same way as symbols of English + alphabet, so some invalid tag names are not rejected. + </li> +<li class="listitem"> + Attribute values which contain <code class="literal"><</code> are not rejected. + </li> +<li class="listitem"> + Invalid entity/character references are not rejected and are instead + left as is. + </li> +<li class="listitem"> + Comment values can contain <code class="literal">--</code>. + </li> +<li class="listitem"> + XML data is not required to begin with document declaration; additionally, + document declaration can appear after comments and other nodes. + </li> +<li class="listitem"> + Invalid document type declarations are silently ignored in some cases. + </li> +</ul></div> +</div> +</div> +<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> +<td align="left"></td> +<td align="right"><div class="copyright-footer">Copyright © 2010 Arseny Kapoulkine<p> + Distributed under the MIT License + </p> +</div></td> +</tr></table> +<hr> +<table width="100%"><tr> +<td>pugixml 0.9 manual | + <a href="../manual.html">Overview</a> | + <a href="install.html">Installation</a> | + Document: + <a href="dom.html">Object model</a> · <b>Loading</b> · <a href="access.html">Accessing</a> · <a href="modify.html">Modifying</a> · <a href="saving.html">Saving</a> | + <a href="xpath.html">XPath</a> | + <a href="apiref.html">API Reference</a> | + <a href="toc.html">Table of Contents</a> +</td> +<td width="*" align="right"><div class="spirit-nav"> +<a accesskey="p" href="dom.html"><img src="../images/prev.png" alt="Prev"></a><a accesskey="u" href="../manual.html"><img src="../images/up.png" alt="Up"></a><a accesskey="h" href="../manual.html"><img src="../images/home.png" alt="Home"></a><a accesskey="n" href="access.html"><img src="../images/next.png" alt="Next"></a> +</div></td> +</tr></table> +</body> +</html> |