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<a href="http://pugixml.org/">pugixml 1.2</a> manual |
<a href="../manual.html">Overview</a> |
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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> |
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<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 for 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><a name="xml_document::load_file_wide"></a><p>
The most common source of XML data is files; pugixml provides dedicated functions
for loading an 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>
<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">wchar_t</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>
These functions accept the 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 the target system, it should have the exact case if
the target file system is case-sensitive, etc.
</p>
<p>
File path is passed to the system file opening function as is in case of
the first function (which accepts <code class="computeroutput"><span class="keyword">const</span>
<span class="keyword">char</span><span class="special">*</span> <span class="identifier">path</span></code>); the second function either uses
a special file opening function if it is provided by the runtime library
or converts the path to UTF-8 and uses the system file opening function.
</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 <a class="link" href="loading.html#xml_parse_result">xml_parse_result</a>
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>
<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 a 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></code> being either <code class="computeroutput"><span class="identifier">strlen</span><span class="special">(</span><span class="identifier">contents</span><span class="special">)</span></code>
or <code class="computeroutput"><span class="identifier">wcslen</span><span class="special">(</span><span class="identifier">contents</span><span class="special">)</span> <span class="special">*</span> <span class="keyword">sizeof</span><span class="special">(</span><span class="keyword">wchar_t</span><span class="special">)</span></code>,
depending on the character type. 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 the 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>
To enhance 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 <a class="link" href="loading.html#encoding_wchar">encoding_wchar</a>). 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>
</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 occurred 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. Note that <code class="computeroutput"><span class="identifier">description</span><span class="special">()</span></code> returns a <code class="computeroutput"><span class="keyword">char</span></code>
string even in <code class="computeroutput"><span class="identifier">PUGIXML_WCHAR_MODE</span></code>;
you'll have to call <a class="link" href="dom.html#as_wide">as_wide</a> to get the <code class="computeroutput"><span class="keyword">wchar_t</span></code> string.
</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 <a class="link" href="dom.html#char_t">pugi::char_t</a> (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>)
is 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_doctype"></a><code class="literal">parse_doctype</code> determines if XML document
type declaration (node with type <a class="link" href="dom.html#node_doctype">node_doctype</a>)
is 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 <a class="link" href="dom.html#node_pcdata">node_pcdata</a>
and value <code class="computeroutput"><span class="string">" "</span></code>,
child with type <a class="link" href="dom.html#node_element">node_element</a> and
name <code class="computeroutput"><span class="string">"a"</span></code>, and another
child with type <a class="link" href="dom.html#node_pcdata">node_pcdata</a> 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.
<br><br>
</li>
<li class="listitem">
<a name="parse_ws_pcdata_single"></a><code class="literal">parse_ws_pcdata_single</code> determines
if whitespace-only PCDATA nodes that have no sibling nodes are to be
put in DOM tree. In some cases application needs to parse the whitespace-only
contents of nodes, i.e. <code class="computeroutput"><span class="special"><</span><span class="identifier">node</span><span class="special">></span>
<span class="special"></</span><span class="identifier">node</span><span class="special">></span></code>, but is not interested in whitespace
markup elsewhere. It is possible to use <a class="link" href="loading.html#parse_ws_pcdata">parse_ws_pcdata</a>
flag in this case, but it results in excessive allocations and complicates
document processing in some cases; this flag is intended to avoid that.
As an 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">a</span><span class="special">></span> <span class="special"></</span><span class="identifier">node</span><span class="special">></span></code> with <code class="computeroutput"><span class="identifier">parse_ws_pcdata_single</span></code>
flag set, <code class="computeroutput"><span class="special"><</span><span class="identifier">node</span><span class="special">></span></code> element will have one child <code class="computeroutput"><span class="special"><</span><span class="identifier">a</span><span class="special">></span></code>, and <code class="computeroutput"><span class="special"><</span><span class="identifier">a</span><span class="special">></span></code>
element will have one child with type <a class="link" href="dom.html#node_pcdata">node_pcdata</a>
and value <code class="computeroutput"><span class="string">" "</span></code>.
This flag has no effect if <a class="link" href="loading.html#parse_ws_pcdata">parse_ws_pcdata</a>
is enabled. 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 on 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 <a class="link" href="loading.html#parse_eol">parse_eol</a>
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 a 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 <a class="link" href="loading.html#parse_wconv_attribute">parse_wconv_attribute</a>
was set, leading and trailing space characters are removed, and all sequences
of space characters are replaced by a single space character. <a class="link" href="loading.html#parse_wconv_attribute">parse_wconv_attribute</a>
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>; <a class="link" href="loading.html#parse_wnorm_attribute">parse_wnorm_attribute</a>
performs transformations required for <code class="literal">NMTOKENS</code> attributes.
In the absence of document type declaration all attributes should behave
as if they are declared as <code class="literal">CDATA</code>, thus <a class="link" href="loading.html#parse_wconv_attribute">parse_wconv_attribute</a>
is the default option.
</p></td></tr>
</table></div>
<p>
Additionally there are three 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,
document type 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 mentioned above,
in practice <a class="link" href="loading.html#parse_default">parse_default</a> 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. <br><br>
</li>
<li class="listitem">
<a name="parse_full"></a><code class="literal">parse_full</code> is the set of flags which adds
nodes of all types to the resulting tree and performs default conversions
for input data. It includes parsing CDATA sections, comments, PI nodes,
document declaration node and document type declaration node, 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
in this mode.
</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 the 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 the 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 the 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 the Unicode standard; the endianness is assumed
to be that of the 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 the 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 the 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 the Unicode standard; the endianness is assumed
to be that of the 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>
<li class="listitem">
<a name="encoding_latin1"></a><code class="literal">encoding_latin1</code> corresponds to ISO-8859-1
encoding (also known as Latin-1).
</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 © 2012 Arseny Kapoulkine<p>
Distributed under the MIT License
</p>
</div></td>
</tr></table>
<hr>
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<td>
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<a href="xpath.html">XPath</a> |
<a href="apiref.html">API Reference</a> |
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