From e418f752f85adcb6de6782e3881ca208156cef39 Mon Sep 17 00:00:00 2001
From: Adrian Johnson <ajohnson@redneon.com>
Date: Mon, 4 Nov 2013 20:58:23 +1030
Subject: [PATCH 6/8] PDFDoc: compress decrypted streams

---
 poppler/PDFDoc.cc | 48 ++++++++++++++++++++++++++++++++++--------------
 poppler/PDFDoc.h  |  3 ++-
 poppler/Stream.h  | 21 +++++++++++++++++++++
 3 files changed, 57 insertions(+), 15 deletions(-)

diff --git a/poppler/PDFDoc.cc b/poppler/PDFDoc.cc
index ab02eda..7590690 100644
--- a/poppler/PDFDoc.cc
+++ b/poppler/PDFDoc.cc
@@ -77,6 +77,7 @@
 #endif
 #include "PDFDoc.h"
 #include "Hints.h"
+#include "DeflateStream.h"
 
 #if MULTITHREADED
 #  define pdfdocLocker()   MutexLocker locker(&mutex)
@@ -990,13 +991,35 @@ void PDFDoc::writeDictionnary (Dict* dict, OutStream* outStr, XRef *xRef, Guint
   outStr->printf(">> ");
 }
 
-void PDFDoc::writeStream (Stream* str, OutStream* outStr)
+// Find the length of this stream after compressing with Deflate
+Goffset PDFDoc::getFlateStreamLength (Stream* str)
 {
+  int n;
+  Guchar buf[4096];
+  NullOutStream nullStr;
+  DeflateStream deflateStr(&nullStr);
+  str->reset();
+  do {
+    n = str->doGetChars(sizeof(buf), buf);
+    deflateStr.write(buf, n);
+  } while (n);
+  deflateStr.close();
+  return nullStr.getNumBytesWritten();
+}
+
+// Write stream using Deflate compression
+void PDFDoc::writeFlateStream (Stream* str, OutStream* outStr)
+{
+  int n;
+  Guchar buf[4096];
   outStr->printf("stream\r\n");
+  DeflateStream deflateStr(outStr);
   str->reset();
-  for (int c=str->getChar(); c!= EOF; c=str->getChar()) {
-    outStr->printf("%c", c);  
-  }
+  do {
+    n = str->doGetChars(sizeof(buf), buf);
+    deflateStr.write(buf, n);
+  } while (n);
+  deflateStr.close();
   outStr->printf("\r\nendstream\r\n");
 }
 
@@ -1093,8 +1116,7 @@ void PDFDoc::writeObject (Object* obj, OutStream* outStr, XRef *xRef, Guint numO
                           CryptAlgorithm encAlgorithm, int keyLength, int objNum, int objGen)
 {
   Array *array;
-  Object obj1;
-  Goffset tmp;
+  Object obj1, obj2;
 
   switch (obj->getType()) {
     case objBool:
@@ -1194,13 +1216,7 @@ void PDFDoc::writeObject (Object* obj, OutStream* outStr, XRef *xRef, Guint numO
             stream = encStream;
           }
 
-          stream->reset();
-          //recalculate stream length
-          tmp = 0;
-          for (int c=stream->getChar(); c!=EOF; c=stream->getChar()) {
-            tmp++;
-          }
-          obj1.initInt64(tmp);
+          obj1.initInt64(getFlateStreamLength(stream));
           stream->getDict()->set("Length", &obj1);
 
           //Remove Stream encoding
@@ -1209,8 +1225,12 @@ void PDFDoc::writeObject (Object* obj, OutStream* outStr, XRef *xRef, Guint numO
           }
           stream->getDict()->remove("DecodeParms");
 
+	  // Set FlateDecode filter
+	  obj2.initName("FlateDecode");
+	  stream->getDict()->set("Filter", &obj2);
+
           writeDictionnary (stream->getDict(),outStr, xRef, numOffset, fileKey, encAlgorithm, keyLength, objNum, objGen);
-          writeStream (stream,outStr);
+          writeFlateStream (stream,outStr);
           delete encStream;
           obj1.free();
         } else {
diff --git a/poppler/PDFDoc.h b/poppler/PDFDoc.h
index 2d62d02..8f576f1 100644
--- a/poppler/PDFDoc.h
+++ b/poppler/PDFDoc.h
@@ -279,7 +279,8 @@ private:
   void writeDictionnary (Dict* dict, OutStream* outStr, Guchar *fileKey, CryptAlgorithm encAlgorithm,
                          int keyLength, int objNum, int objGen)
   { writeDictionnary(dict, outStr, getXRef(), 0, fileKey, encAlgorithm, keyLength, objNum, objGen); }
-  static void writeStream (Stream* str, OutStream* outStr);
+  static Goffset getFlateStreamLength (Stream* str);
+  static void writeFlateStream (Stream* str, OutStream* outStr);
   static void writeRawStream (Stream* str, OutStream* outStr);
   void writeXRefTableTrailer (Goffset uxrefOffset, XRef *uxref, GBool writeAllEntries,
                               int uxrefSize, OutStream* outStr, GBool incrUpdate);
diff --git a/poppler/Stream.h b/poppler/Stream.h
index ae089b0..3f21ca4 100644
--- a/poppler/Stream.h
+++ b/poppler/Stream.h
@@ -303,6 +303,27 @@ private:
 
 };
 
+//------------------------------------------------------------------------
+// NullOutStream
+//------------------------------------------------------------------------
+class NullOutStream : public OutStream {
+public:
+  NullOutStream () { count = 0;};
+
+  ~NullOutStream () {};
+
+  Goffset getNumBytesWritten() { return count; }
+
+  void close() {}
+
+  Goffset getPos() { return 0; }
+
+  void write (const Guchar *data, long length) { count += length; }
+
+private:
+  Goffset count;
+};
+
 
 //------------------------------------------------------------------------
 // BaseStream
-- 
1.8.3.2