From b0846152c522c859bee2fbce55721d7b79264848 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 27 Nov 2009 18:17:22 +0200
Subject: Add XML compression example

---
 .../tree/compression/compressed-input-source.cxx   | 215 +++++++++++++++++++++
 1 file changed, 215 insertions(+)
 create mode 100644 examples/cxx/tree/compression/compressed-input-source.cxx

(limited to 'examples/cxx/tree/compression/compressed-input-source.cxx')

diff --git a/examples/cxx/tree/compression/compressed-input-source.cxx b/examples/cxx/tree/compression/compressed-input-source.cxx
new file mode 100644
index 0000000..22d09ff
--- /dev/null
+++ b/examples/cxx/tree/compression/compressed-input-source.cxx
@@ -0,0 +1,215 @@
+// file      : examples/cxx/tree/compression/compressed-input-source.cxx
+// author    : Boris Kolpackov <boris@codesynthesis.com>
+// copyright : not copyrighted - public domain
+
+#include <istream>
+
+#include <xsd/cxx/xml/string.hxx>
+
+#include "compressed-input-source.hxx"
+
+using namespace std;
+using namespace xercesc;
+namespace xml = xsd::cxx::xml;
+
+//
+// decompression_failure
+//
+
+const char* decompression_failure::
+what () const throw ()
+{
+  return "decompression failure";
+}
+
+//
+// compressed_input_source
+//
+
+compressed_input_source::
+compressed_input_source (istream& is, compression_type t)
+    : is_ (&is), type_ (t)
+{
+}
+
+compressed_input_source::
+compressed_input_source (istream& is,
+                         compression_type t,
+                         const string& sysid)
+    : InputSource (xml::string (sysid).c_str ()), is_ (&is), type_ (t)
+{
+}
+
+compressed_input_source::
+compressed_input_source (istream& is,
+                         compression_type t,
+                         const string& sysid,
+                         const string& pubid)
+    : xercesc::InputSource (xml::string (sysid).c_str (),
+                            xml::string (pubid).c_str ()),
+      is_ (&is),
+      type_ (t)
+{
+}
+
+BinInputStream* compressed_input_source::
+makeStream () const
+{
+  if (is_ == 0)
+    throw copy ();
+
+  istream& is (*is_);
+  is_ = 0;
+  return new compressed_input_stream (
+    is, static_cast<compressed_input_stream::compression_type> (type_));
+}
+
+//
+// compressed_input_stream
+//
+
+compressed_input_stream::
+compressed_input_stream (istream& is, compression_type t)
+    : is_ (is), end_ (false), pos_ (0)
+{
+  zs_.zalloc = Z_NULL;
+  zs_.zfree  = Z_NULL;
+  zs_.opaque = Z_NULL;
+  zs_.next_in = Z_NULL;
+  zs_.avail_in = 0;
+
+  int window = 0;
+
+  switch (t)
+  {
+  case raw:
+    {
+      window = -15;
+      break;
+    }
+  case zlib:
+    {
+      window = 15;
+      break;
+    }
+  case gzip:
+    {
+      window = 16 + 15;
+      break;
+    }
+  }
+
+  int r (inflateInit2 (&zs_, window));
+
+  if (r != Z_OK)
+    throw decompression_failure (r);
+}
+
+compressed_input_stream::
+~compressed_input_stream ()
+{
+  inflateEnd (&zs_);
+}
+
+#if _XERCES_VERSION >= 30000
+XMLFilePos compressed_input_stream::
+curPos () const
+{
+  return static_cast<XMLFilePos> (pos_);
+}
+#else
+unsigned int compressed_input_stream::
+curPos () const
+{
+  return static_cast<unsigned int> (pos_);
+}
+#endif
+
+#if _XERCES_VERSION >= 30000
+XMLSize_t compressed_input_stream::
+readBytes (XMLByte* const buf, const XMLSize_t size)
+#else
+unsigned int compressed_input_stream::
+readBytes (XMLByte* const buf, const unsigned int size)
+#endif
+{
+  if (end_)
+    return 0;
+
+  // Keep calling inflate() until we fill up the buffer or reach the
+  // end of stream. If we run out of input data, call the underlying
+  // stream for more.
+  //
+  zs_.next_out = reinterpret_cast<Bytef*> (buf);
+  zs_.avail_out = static_cast<uInt> (size);
+
+  int r;
+
+  do
+  {
+    if (zs_.avail_in == 0)
+    {
+      zs_.avail_in = static_cast<uInt> (read ());
+      zs_.next_in = reinterpret_cast<Bytef*> (const_cast<char*> (in_));
+
+      if (zs_.avail_in == 0)
+        throw decompression_failure (Z_DATA_ERROR);
+    }
+
+    r = inflate (&zs_, Z_NO_FLUSH);
+
+    if (r != Z_OK && r != Z_STREAM_END)
+      throw decompression_failure (r);
+
+  } while (r != Z_STREAM_END && zs_.avail_out != 0);
+
+  if (r == Z_STREAM_END)
+    end_ = true;
+
+  size_t n (size - zs_.avail_out);
+  pos_ += n;
+
+#if _XERCES_VERSION >= 30000
+  return static_cast<XMLSize_t> (n);
+#else
+  return static_cast<unsigned int> (n);
+#endif
+}
+
+#if _XERCES_VERSION >= 30000
+const XMLCh* compressed_input_stream::
+getContentType () const
+{
+  return 0;
+}
+#endif
+
+size_t compressed_input_stream::
+read ()
+{
+  // Some implementations don't clear gcount if you call read() on a
+  // stream that is in the eof state.
+  //
+  if (is_.eof ())
+    return 0;
+
+  // Unset the exception failbit while we are working with the stream.
+  //
+  ios_base::iostate old (is_.exceptions ());
+  is_.exceptions (old & ~ios_base::failbit);
+
+  is_.read (in_, static_cast<streamsize> (buf_size_));
+
+  // Clear the fail bit if it was caused by eof and restore the original
+  // exception state. If there are any pending errors then the exception
+  // will be thrown now.
+  //
+  if (is_.fail () && is_.eof ())
+    is_.clear (is_.rdstate () & ~ios_base::failbit);
+
+  is_.exceptions (old);
+
+  // Make sure that if we failed, we won't be called again.
+  //
+  return !is_.fail () ? static_cast<size_t> (is_.gcount ()) : 0;
+}
-- 
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