0
0
mirror of https://github.com/zeux/pugixml.git synced 2024-12-28 23:03:00 +08:00
pugixml/docs/manual/saving.html
2010-09-24 05:44:13 +00:00

474 lines
44 KiB
HTML

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Saving 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="modify.html" title="Modifying document data">
<link rel="next" href="xpath.html" title="XPath">
</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> &middot; <a href="loading.html">Loading</a> &middot; <a href="access.html">Accessing</a> &middot; <a href="modify.html">Modifying</a> &middot; <b>Saving</b> |
<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="modify.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="xpath.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.saving"></a><a class="link" href="saving.html" title="Saving document"> Saving document</a>
</h2></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="saving.html#manual.saving.file"> Saving document to a file</a></span></dt>
<dt><span class="section"><a href="saving.html#manual.saving.stream"> Saving document to C++ IOstreams</a></span></dt>
<dt><span class="section"><a href="saving.html#manual.saving.writer"> Saving document via writer interface</a></span></dt>
<dt><span class="section"><a href="saving.html#manual.saving.subtree"> Saving a single subtree</a></span></dt>
<dt><span class="section"><a href="saving.html#manual.saving.options"> Output options</a></span></dt>
<dt><span class="section"><a href="saving.html#manual.saving.encoding"> Encodings</a></span></dt>
</dl></div>
<p>
Often after creating a new document or loading the existing one and processing
it, it is necessary to save the result back to file. Also it is occasionally
useful to output the whole document or a subtree to some stream; use cases
include debug printing, serialization via network or other text-oriented medium,
etc. pugixml provides several functions to output any subtree of the document
to a file, stream or another generic transport interface; these functions allow
to customize the output format (see <a class="xref" href="saving.html#manual.saving.options" title="Output options"> Output options</a>), and also perform
necessary encoding conversions (see <a class="xref" href="saving.html#manual.saving.encoding" title="Encodings"> Encodings</a>). This section documents
the relevant functionality.
</p>
<p>
The node/attribute data is written to the destination properly formatted according
to the node type; all special XML symbols, such as &lt; and &amp;, are properly
escaped. In order to guard against forgotten node/attribute names, empty node/attribute
names are printed as <code class="computeroutput"><span class="string">":anonymous"</span></code>.
For proper output, make sure all node and attribute names are set to meaningful
values.
</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>
Currently the content of CDATA sections is not escaped, so CDATA sections
with values that contain <code class="computeroutput"><span class="string">"]]&gt;"</span></code>
will result in malformed document. This will be fixed in version 1.0.
</p></td></tr>
</table></div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="manual.saving.file"></a><a class="link" href="saving.html#manual.saving.file" title="Saving document to a file"> Saving document to a file</a>
</h3></div></div></div>
<a name="xml_document::save_file"></a><p>
If you want to save the whole document to a file, you can use the following
function:
</p>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">save_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">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">indent</span> <span class="special">=</span> <span class="string">"\t"</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">flags</span> <span class="special">=</span> <span class="identifier">format_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="keyword">const</span><span class="special">;</span>
</pre>
<p>
This function accepts file path as its first argument, and also three optional
arguments, which specify indentation and other output options (see <a class="xref" href="saving.html#manual.saving.options" title="Output options"> Output options</a>)
and output data encoding (see <a class="xref" href="saving.html#manual.saving.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>
<a name="xml_writer_file"></a><p>
<code class="computeroutput"><span class="identifier">save_file</span></code> opens the target
file for writing, outputs the requested header (by default a document declaration
is output, unless the document already has one), and then saves the document
contents. If the file could not be opened, the function returns <code class="computeroutput"><span class="keyword">false</span></code>. Calling <code class="computeroutput"><span class="identifier">save_file</span></code>
is equivalent to creating an <code class="computeroutput"><span class="identifier">xml_writer_file</span></code>
object with <code class="computeroutput"><span class="identifier">FILE</span><span class="special">*</span></code>
handle as the only constructor argument and then calling <code class="computeroutput"><span class="identifier">save</span></code>;
see <a class="xref" href="saving.html#manual.saving.writer" title="Saving document via writer interface"> Saving document via writer interface</a> for writer interface 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 saving XML document to wide
character paths. 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-saving functions as a workaround if your
STL implementation can open file streams via wchar_t paths.
</p></td></tr>
</table></div>
<p>
This is a simple example of saving XML document to file (<a href="../samples/save_file.cpp" target="_top">samples/save_file.cpp</a>):
</p>
<p>
</p>
<pre class="programlisting"><span class="comment">// save document to file
</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"Saving result: "</span> <span class="special">&lt;&lt;</span> <span class="identifier">doc</span><span class="special">.</span><span class="identifier">save_file</span><span class="special">(</span><span class="string">"save_file_output.xml"</span><span class="special">)</span> <span class="special">&lt;&lt;</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.saving.stream"></a><a class="link" href="saving.html#manual.saving.stream" title="Saving document to C++ IOstreams"> Saving document to C++ IOstreams</a>
</h3></div></div></div>
<a name="xml_document::save_stream"></a><p>
For additional interoperability pugixml provides functions for saving document
to any object which implements C++ std::ostream interface. This allows you
to save documents to any standard C++ stream (i.e. file stream) or any third-party
compliant implementation (i.e. Boost Iostreams). Most notably, this allows
for easy debug output, since you can use <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span></code>
stream as saving target. There are two functions, one works with narrow character
streams, another handles wide character ones:
</p>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">save</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">ostream</span><span class="special">&amp;</span> <span class="identifier">stream</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">indent</span> <span class="special">=</span> <span class="string">"\t"</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">flags</span> <span class="special">=</span> <span class="identifier">format_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="keyword">const</span><span class="special">;</span>
<span class="keyword">void</span> <span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">save</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">wostream</span><span class="special">&amp;</span> <span class="identifier">stream</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">indent</span> <span class="special">=</span> <span class="string">"\t"</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">flags</span> <span class="special">=</span> <span class="identifier">format_default</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
</pre>
<p>
<code class="computeroutput"><span class="identifier">save</span></code> with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">ostream</span></code>
argument saves the document to the stream in the same way as <code class="computeroutput"><span class="identifier">save_file</span></code> (i.e. with requested header and
with encoding conversions). On the other hand, <code class="computeroutput"><span class="identifier">save</span></code>
with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">wstream</span></code> argument saves the document to
the wide stream with <code class="computeroutput"><span class="identifier">encoding_wchar</span></code>
encoding. Because of this, using <code class="computeroutput"><span class="identifier">save</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 with the ability to save documents to non-Unicode encodings, i.e. you
can save Shift-JIS encoded data if you set the correct locale.
</p>
<a name="xml_writer_stream"></a><p>
Calling <code class="computeroutput"><span class="identifier">save</span></code> with stream
target is equivalent to creating an <code class="computeroutput"><span class="identifier">xml_writer_stream</span></code>
object with stream as the only constructor argument and then calling <code class="computeroutput"><span class="identifier">save</span></code>; see <a class="xref" href="saving.html#manual.saving.writer" title="Saving document via writer interface"> Saving document via writer interface</a> for writer
interface details.
</p>
<p>
This is a simple example of saving XML document to standard output (<a href="../samples/save_stream.cpp" target="_top">samples/save_stream.cpp</a>):
</p>
<p>
</p>
<pre class="programlisting"><span class="comment">// save document to standard output
</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"Document:\n"</span><span class="special">;</span>
<span class="identifier">doc</span><span class="special">.</span><span class="identifier">save</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span><span class="special">);</span>
</pre>
<p>
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="manual.saving.writer"></a><a class="link" href="saving.html#manual.saving.writer" title="Saving document via writer interface"> Saving document via writer interface</a>
</h3></div></div></div>
<a name="xml_document::save"></a><a name="xml_writer"></a><a name="xml_writer::write"></a><p>
All of the above saving functions are implemented in terms of writer interface.
This is a simple interface with a single function, which is called several
times during output process with chunks of document data as input:
</p>
<pre class="programlisting"><span class="keyword">class</span> <span class="identifier">xml_writer</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="keyword">virtual</span> <span class="keyword">void</span> <span class="identifier">write</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">void</span><span class="special">*</span> <span class="identifier">data</span><span class="special">,</span> <span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">)</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span>
<span class="special">};</span>
<span class="keyword">void</span> <span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">save</span><span class="special">(</span><span class="identifier">xml_writer</span><span class="special">&amp;</span> <span class="identifier">writer</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">indent</span> <span class="special">=</span> <span class="string">"\t"</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">flags</span> <span class="special">=</span> <span class="identifier">format_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="keyword">const</span><span class="special">;</span>
</pre>
<p>
In order to output the document via some custom transport, for example sockets,
you should create an object which implements <code class="computeroutput"><span class="identifier">xml_writer_file</span></code>
interface and pass it to <code class="computeroutput"><span class="identifier">save</span></code>
function. <code class="computeroutput"><span class="identifier">xml_writer_file</span><span class="special">::</span><span class="identifier">write</span></code>
function is called with a buffer as an input, where <code class="computeroutput"><span class="identifier">data</span></code>
points to buffer start, and <code class="computeroutput"><span class="identifier">size</span></code>
is equal to the buffer size in bytes. <code class="computeroutput"><span class="identifier">write</span></code>
implementation must write the buffer to the transport; it can not save the
passed buffer pointer, as the buffer contents will change after <code class="computeroutput"><span class="identifier">write</span></code> returns. The buffer contains the
chunk of document data in the desired encoding.
</p>
<p>
<code class="computeroutput"><span class="identifier">write</span></code> function is called
with relatively large blocks (size is usually several kilobytes, except for
the first block with BOM, which is output only if <code class="computeroutput"><span class="identifier">format_write_bom</span></code>
is set, and last block, which may be small), so there is often no need for
additional buffering in the implementation.
</p>
<p>
This is a simple example of custom writer for saving document data to STL
string (<a href="../samples/save_custom_writer.cpp" target="_top">samples/save_custom_writer.cpp</a>);
read the sample code for more complex examples:
</p>
<p>
</p>
<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">xml_string_writer</span><span class="special">:</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">xml_writer</span>
<span class="special">{</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">result</span><span class="special">;</span>
<span class="keyword">virtual</span> <span class="keyword">void</span> <span class="identifier">write</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">void</span><span class="special">*</span> <span class="identifier">data</span><span class="special">,</span> <span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">)</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">string</span><span class="special">(</span><span class="keyword">static_cast</span><span class="special">&lt;</span><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*&gt;(</span><span class="identifier">data</span><span class="special">),</span> <span class="identifier">size</span><span class="special">);</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.saving.subtree"></a><a class="link" href="saving.html#manual.saving.subtree" title="Saving a single subtree"> Saving a single subtree</a>
</h3></div></div></div>
<a name="xml_node::print"></a><a name="xml_node::print_stream"></a><p>
While the previously described functions saved the whole document to the
destination, it is easy to save a single subtree. The following functions
are provided:
</p>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">print</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">ostream</span><span class="special">&amp;</span> <span class="identifier">os</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">indent</span> <span class="special">=</span> <span class="string">"\t"</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">flags</span> <span class="special">=</span> <span class="identifier">format_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="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">depth</span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">void</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">print</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">wostream</span><span class="special">&amp;</span> <span class="identifier">os</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">indent</span> <span class="special">=</span> <span class="string">"\t"</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">flags</span> <span class="special">=</span> <span class="identifier">format_default</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">depth</span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">void</span> <span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">print</span><span class="special">(</span><span class="identifier">xml_writer</span><span class="special">&amp;</span> <span class="identifier">writer</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">char_t</span><span class="special">*</span> <span class="identifier">indent</span> <span class="special">=</span> <span class="string">"\t"</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">flags</span> <span class="special">=</span> <span class="identifier">format_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="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">depth</span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
</pre>
<p>
These functions have the same arguments with the same meaning as the corresponding
<code class="computeroutput"><span class="identifier">xml_document</span><span class="special">::</span><span class="identifier">save</span></code> functions, and allow you to save the
subtree to either a C++ IOstream or to any object that implements <code class="computeroutput"><span class="identifier">xml_writer</span></code> interface.
</p>
<p>
Saving a subtree differs from saving the whole document: the process behaves
as if <code class="computeroutput"><span class="identifier">format_write_bom</span></code> is
off, and <code class="computeroutput"><span class="identifier">format_no_declaration</span></code>
is on, even if actual values of the flags are different. This means that
BOM is not written to the destination, and document declaration is only written
if it is the node itself or is one of node's children. Note that this also
holds if you're saving a document; this example (<a href="../samples/save_subtree.cpp" target="_top">samples/save_subtree.cpp</a>)
illustrates the difference:
</p>
<p>
</p>
<pre class="programlisting"><span class="comment">// get a test document
</span><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">doc</span><span class="special">.</span><span class="identifier">load</span><span class="special">(</span><span class="string">"&lt;foo bar='baz'&gt;&lt;call&gt;hey&lt;/call&gt;&lt;/foo&gt;"</span><span class="special">);</span>
<span class="comment">// print document to standard output (prints &lt;?xml version="1.0"?&gt;&lt;foo bar="baz"&gt;&lt;call&gt;hey&lt;/call&gt;&lt;/foo&gt;)
</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">save</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">""</span><span class="special">,</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">format_raw</span><span class="special">);</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
<span class="comment">// print document to standard output as a regular node (prints &lt;foo bar="baz"&gt;&lt;call&gt;hey&lt;/call&gt;&lt;/foo&gt;)
</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">print</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">""</span><span class="special">,</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">format_raw</span><span class="special">);</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
<span class="comment">// print a subtree to standard output (prints &lt;call&gt;hey&lt;/call&gt;)
</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">child</span><span class="special">(</span><span class="string">"foo"</span><span class="special">).</span><span class="identifier">child</span><span class="special">(</span><span class="string">"call"</span><span class="special">).</span><span class="identifier">print</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">""</span><span class="special">,</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">format_raw</span><span class="special">);</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</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.saving.options"></a><a class="link" href="saving.html#manual.saving.options" title="Output options"> Output options</a>
</h3></div></div></div>
<p>
All saving functions accept the optional parameter <code class="computeroutput"><span class="identifier">flags</span></code>.
This is a bitmask that customizes the output format; you can select the way
the document nodes are printed and select the needed additional information
that is output before the document contents.
</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">&amp;</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="format_indent"></a><code class="literal">format_indent</code> determines if all nodes
should be indented with the indentation string (this is an additional
parameter for all saving functions, and is <code class="computeroutput"><span class="string">"\t"</span></code>
by default). If this flag is on, before every node the indentation string
is output several times, where the amount of indentation depends on the
node's depth relative to the output subtree. This flag has no effect
if <code class="computeroutput"><span class="identifier">format_raw</span></code> is enabled.
This flag is <span class="bold"><strong>on</strong></span> by default. <br><br>
</li>
<li class="listitem">
<a name="format_raw"></a><code class="literal">format_raw</code> switches between formatted and
raw output. If this flag is on, the nodes are not indented in any way,
and also no newlines that are not part of document text are printed.
Raw mode can be used for serialization where the result is not intended
to be read by humans; also it can be useful if the document was parsed
with <code class="computeroutput"><span class="identifier">parse_ws_pcdata</span></code>
flag, to preserve the original document formatting as much as possible.
This flag is <span class="bold"><strong>off</strong></span> by default.
</li>
</ul></div>
<p>
These flags control the additional output information:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
<a name="format_no_declaration"></a><code class="literal">format_no_declaration</code> allows
to disable default node declaration output. By default, if the document
is saved via <code class="computeroutput"><span class="identifier">save</span></code> or
<code class="computeroutput"><span class="identifier">save_file</span></code> function, and
it does not have any document declaration, a default declaration is output
before the document contents. Enabling this flag disables this declaration.
This flag has no effect in <code class="computeroutput"><span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">print</span></code>
functions: they never output the default declaration. This flag is <span class="bold"><strong>off</strong></span> by default. <br><br>
</li>
<li class="listitem">
<a name="format_write_bom"></a><code class="literal">format_write_bom</code> allows to enable
Byte Order Mark (BOM) output. By default, no BOM is output, so in case
of non UTF-8 encodings the resulting document's encoding may not be recognized
by some parsers and text editors, if they do not implement sophisticated
encoding detection. Enabling this flag adds an encoding-specific BOM
to the output. This flag has no effect in <code class="computeroutput"><span class="identifier">xml_node</span><span class="special">::</span><span class="identifier">print</span></code>
functions: they never output the BOM. This flag is <span class="bold"><strong>off</strong></span>
by default.
</li>
</ul></div>
<p>
Additionally, there is one predefined option mask:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<a name="format_default"></a><code class="literal">format_default</code> is the default set of
flags, i.e. it has all options set to their default values. It sets formatted
output with indentation, without BOM and with default node declaration,
if necessary.
</li></ul></div>
<p>
This is an example that shows the outputs of different output options (<a href="../samples/save_options.cpp" target="_top">samples/save_options.cpp</a>):
</p>
<p>
</p>
<pre class="programlisting"><span class="comment">// get a test document
</span><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">doc</span><span class="special">.</span><span class="identifier">load</span><span class="special">(</span><span class="string">"&lt;foo bar='baz'&gt;&lt;call&gt;hey&lt;/call&gt;&lt;/foo&gt;"</span><span class="special">);</span>
<span class="comment">// default options; prints
</span><span class="comment">// &lt;?xml version="1.0"?&gt;
</span><span class="comment">// &lt;foo bar="baz"&gt;
</span><span class="comment">// &lt;call&gt;hey&lt;/call&gt;
</span><span class="comment">// &lt;/foo&gt;
</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">save</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="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
<span class="comment">// default options with custom indentation string; prints
</span><span class="comment">// &lt;?xml version="1.0"?&gt;
</span><span class="comment">// &lt;foo bar="baz"&gt;
</span><span class="comment">// --&lt;call&gt;hey&lt;/call&gt;
</span><span class="comment">// &lt;/foo&gt;
</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">save</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">"--"</span><span class="special">);</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
<span class="comment">// default options without indentation; prints
</span><span class="comment">// &lt;?xml version="1.0"?&gt;
</span><span class="comment">// &lt;foo bar="baz"&gt;
</span><span class="comment">// &lt;call&gt;hey&lt;/call&gt;
</span><span class="comment">// &lt;/foo&gt;
</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">save</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">"\t"</span><span class="special">,</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">format_default</span> <span class="special">&amp;</span> <span class="special">~</span><span class="identifier">pugi</span><span class="special">::</span><span class="identifier">format_indent</span><span class="special">);</span> <span class="comment">// can also pass "" instead of indentation string for the same effect
</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
<span class="comment">// raw output; prints
</span><span class="comment">// &lt;?xml version="1.0"?&gt;&lt;foo bar="baz"&gt;&lt;call&gt;hey&lt;/call&gt;&lt;/foo&gt;
</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">save</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">"\t"</span><span class="special">,</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">format_raw</span><span class="special">);</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
<span class="comment">// raw output without declaration; prints
</span><span class="comment">// &lt;foo bar="baz"&gt;&lt;call&gt;hey&lt;/call&gt;&lt;/foo&gt;
</span><span class="identifier">doc</span><span class="special">.</span><span class="identifier">save</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">"\t"</span><span class="special">,</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">format_raw</span> <span class="special">|</span> <span class="identifier">pugi</span><span class="special">::</span><span class="identifier">format_no_declaration</span><span class="special">);</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</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.saving.encoding"></a><a class="link" href="saving.html#manual.saving.encoding" title="Encodings"> Encodings</a>
</h3></div></div></div>
<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 during
output. The output encoding is set via the <code class="computeroutput"><span class="identifier">encoding</span></code>
parameter of saving functions, which is of type <code class="computeroutput"><span class="identifier">xml_encoding</span></code>.
The possible values for the encoding are documented in <a class="xref" href="loading.html#manual.loading.encoding" title="Encodings"> Encodings</a>;
the only flag that has a different meaning is <code class="computeroutput"><span class="identifier">encoding_auto</span></code>.
</p>
<p>
While all other flags set the exact encoding, <code class="computeroutput"><span class="identifier">encoding_auto</span></code>
is meant for automatic encoding detection. The automatic detection does not
make sense for output encoding, since there is usually nothing to infer the
actual encoding from, so here <code class="computeroutput"><span class="identifier">encoding_auto</span></code>
means UTF-8 encoding, which is the most popular encoding for XML data storage.
This is also the default value of output encoding; specify another value
if you do not want UTF-8 encoded output.
</p>
<p>
Also note that wide stream saving functions do not have <code class="computeroutput"><span class="identifier">encoding</span></code>
argument and always assume <code class="computeroutput"><span class="identifier">encoding_wchar</span></code>
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; if
your node/attribute names do not contain any valid UTF sequences, they
may be output as if they are empty, which will result in malformed XML
document.
</p></td></tr>
</table></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 &#169; 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> &middot; <a href="loading.html">Loading</a> &middot; <a href="access.html">Accessing</a> &middot; <a href="modify.html">Modifying</a> &middot; <b>Saving</b> |
<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="modify.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="xpath.html"><img src="../images/next.png" alt="Next"></a>
</div></td>
</tr></table>
</body>
</html>