Attachment 60487 Details for Bug 49080 – Proof-of-concept patch

[patch] Proof-of-concept patch

0001-saveIncrementalUpdate-Output-a-xref-stream-if-there-.patch (text/plain), 8.18 KB, created by Fabio D'Urso on 2012-04-23 09:08:25 UTC

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Creator: Fabio D'Urso

Created: 2012-04-23 09:08:25 UTC

Size: 8.18 KB

patch

obsolete

>From 6708c12fd4acdd4b9e863a63efea29205f472eaf Mon Sep 17 00:00:00 2001
>From: Fabio D'Urso <fabiodurso@hotmail.it>
>Date: Mon, 23 Apr 2012 11:55:46 +0200
>Subject: [PATCH] saveIncrementalUpdate: Output a xref stream if there was a
> xref stream already
>
>---
> poppler/PDFDoc.cc |   45 +++++++++++++++++++++++++++++++-----------
> poppler/PDFDoc.h  |    4 +-
> poppler/XRef.cc   |   56 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> poppler/XRef.h    |    3 ++
> 4 files changed, 94 insertions(+), 14 deletions(-)
>
>diff --git a/poppler/PDFDoc.cc b/poppler/PDFDoc.cc
>index 898bcbb..23896ce 100644
>--- a/poppler/PDFDoc.cc
>+++ b/poppler/PDFDoc.cc
>@@ -721,7 +721,7 @@ int PDFDoc::savePageAs(GooString *name, int pageNo)
>   Ref ref;
>   ref.num = rootNum;
>   ref.gen = 0;
>-  writeTrailer(uxrefOffset, objectsCount, outStr, gFalse, 0, &ref, getXRef(), name->getCString(), outStr->getPos());
>+  writeTrailer(uxrefOffset, objectsCount, outStr, gFalse, 0, &ref, getXRef(), name->getCString(), outStr->getPos(), NULL);
> 
>   outStr->close();
>   fclose(f);
>@@ -862,9 +862,18 @@ void PDFDoc::saveIncrementalUpdate (OutStream* outStr)
>   }
> 
>   Guint uxrefOffset = outStr->getPos();
>-  uxref->writeToFile(outStr, gFalse /* do not write unnecessary entries */);
>-
>-  writeTrailer(uxrefOffset, xref->getNumObjects(), outStr, gTrue);
>+  int numobjects = xref->getNumObjects();
>+
>+  // Output a xref stream if and only if there was a xref stream already
>+  if (xref->isXRefStream()) {
>+    // Append an entry for the xref stream itself and write its ref
>+    outStr->printf("%d 0 obj ", numobjects);
>+    uxref->add(numobjects++, 0, uxrefOffset, gTrue);
>+    writeTrailer(uxrefOffset, numobjects, outStr, gTrue, uxref /* Output XRef stream */ );
>+  } else {
>+    uxref->writeToFile(outStr, gFalse /* do not write unnecessary entries */);
>+    writeTrailer(uxrefOffset, numobjects, outStr, gTrue, NULL);
>+  }
> 
>   delete uxref;
> }
>@@ -904,8 +913,7 @@ void PDFDoc::saveCompleteRewrite (OutStream* outStr)
>   Guint uxrefOffset = outStr->getPos();
>   uxref->writeToFile(outStr, gTrue /* write all entries */);
> 
>-  writeTrailer(uxrefOffset, uxref->getNumObjects(), outStr, gFalse);
>-
>+  writeTrailer(uxrefOffset, uxref->getNumObjects(), outStr, gFalse, NULL);
> 
>   delete uxref;
> 
>@@ -1112,7 +1120,7 @@ Guint PDFDoc::writeObject (Object* obj, Ref* ref, OutStream* outStr, XRef *xRef,
> void PDFDoc::writeTrailer(Guint uxrefOffset, int uxrefSize, 
> 			  OutStream* outStr, GBool incrUpdate,
> 			  Guint startxRef, Ref *root, XRef *xRef, const char *fileName,
>-			  Guint fileSize)
>+			  Guint fileSize, XRef *uxrefStm)
> {
>   Dict *trailerDict = new Dict(xRef);
>   Object obj1;
>@@ -1195,16 +1203,29 @@ void PDFDoc::writeTrailer(Guint uxrefOffset, int uxrefSize,
>     }
>   }
>   
>-  outStr->printf( "trailer\r\n");
>-  writeDictionnary(trailerDict, outStr, xRef, 0);
>-  outStr->printf( "\r\nstartxref\r\n");
>+  // A NULL uxrefStm means that we're writing a classic XRef table
>+  if (uxrefStm) {
>+    /* Object ref (ie: "<n> 0 obj\r\n") was already written by the caller */
>+    GooString stmData;
>+    uxrefStm->outputXRefStm(&stmData, trailerDict, xRef);
>+    MemStream *mStream = new MemStream( stmData.getCString(), 0,
>+                                        stmData.getLength(), obj1.initDict(trailerDict) );
>+    writeObject(obj1.initStream(mStream), NULL, outStr, xRef, 0);
>+    obj1.free();
>+  } else {
>+    /* XRef table was already written by the caller */
>+    outStr->printf( "trailer\r\n");
>+    writeDictionnary(trailerDict, outStr, xRef, 0);
>+    outStr->printf( "\r\n");
>+  }
>+  outStr->printf( "startxref\r\n");
>   outStr->printf( "%i\r\n", uxrefOffset);
>   outStr->printf( "%%%%EOF\r\n");
> 
>   delete trailerDict;
> }
> 
>-void PDFDoc::writeTrailer(Guint uxrefOffset, int uxrefSize, OutStream* outStr, GBool incrUpdate)
>+void PDFDoc::writeTrailer(Guint uxrefOffset, int uxrefSize, OutStream* outStr, GBool incrUpdate, XRef *uxrefStm)
> {
>   const char *fileNameA;
>   if (fileName)
>@@ -1222,7 +1243,7 @@ void PDFDoc::writeTrailer(Guint uxrefOffset, int uxrefSize, OutStream* outStr, G
>   Ref ref;
>   ref.num = getXRef()->getRootNum();
>   ref.gen = getXRef()->getRootGen();
>-  writeTrailer(uxrefOffset, uxrefSize, outStr, incrUpdate, getStartXRef(), &ref, getXRef(), fileNameA, fileSize);
>+  writeTrailer(uxrefOffset, uxrefSize, outStr, incrUpdate, getStartXRef(), &ref, getXRef(), fileNameA, fileSize, uxrefStm);
> }
> 
> void PDFDoc::writeHeader(OutStream *outStr, int major, int minor)
>diff --git a/poppler/PDFDoc.h b/poppler/PDFDoc.h
>index ccb1b22..b8aeb86 100644
>--- a/poppler/PDFDoc.h
>+++ b/poppler/PDFDoc.h
>@@ -245,7 +245,7 @@ public:
>   static Guint writeObject (Object *obj, Ref *ref, OutStream* outStr, XRef *xref, Guint numOffset);
>   static void writeHeader(OutStream *outStr, int major, int minor);
>   static void writeTrailer (Guint uxrefOffset, int uxrefSize, OutStream* outStr, GBool incrUpdate,
>-                            Guint startxRef, Ref *root, XRef *xRef, const char *fileName, Guint fileSize);
>+                            Guint startxRef, Ref *root, XRef *xRef, const char *fileName, Guint fileSize, XRef *uxref);
> 
> private:
>   // insert referenced objects in XRef
>@@ -260,7 +260,7 @@ private:
>   { writeDictionnary(dict, outStr, getXRef(), 0); }
>   static void writeStream (Stream* str, OutStream* outStr);
>   static void writeRawStream (Stream* str, OutStream* outStr);
>-  void writeTrailer (Guint uxrefOffset, int uxrefSize, OutStream* outStr, GBool incrUpdate);
>+  void writeTrailer (Guint uxrefOffset, int uxrefSize, OutStream* outStr, GBool incrUpdate, XRef *uxrefStm);
>   static void writeString (GooString* s, OutStream* outStr);
>   void saveIncrementalUpdate (OutStream* outStr);
>   void saveCompleteRewrite (OutStream* outStr);
>diff --git a/poppler/XRef.cc b/poppler/XRef.cc
>index dfc6d73..9c120fb 100644
>--- a/poppler/XRef.cc
>+++ b/poppler/XRef.cc
>@@ -1288,6 +1288,62 @@ void XRef::writeToFile(OutStream* outStr, GBool writeAllEntries) {
>   }
> }
> 
>+void XRef::outputXRefStm(GooString *stmBuf, Dict *xrefDict, XRef *xref) {
>+  //create free entries linked-list
>+  if (getEntry(0)->gen != 65535) {
>+    error(errInternal, -1, "XRef::outputXRefStm, entry 0 of the XRef is invalid (gen != 65535)\n");
>+  }
>+  int lastFreeEntry = 0;
>+  for (int i=0; i<size; i++) {
>+    if (getEntry(i)->type == xrefEntryFree) {
>+      getEntry(lastFreeEntry)->offset = i;
>+      lastFreeEntry = i;
>+    }
>+  }
>+
>+  Object index;
>+  index.initArray(xref);
>+  stmBuf->clear();
>+  int i = 0;
>+  while (i < size) {
>+    int j;
>+    for(j=i; j<size; j++) { //look for consecutive entries
>+      if ((getEntry(j)->type == xrefEntryFree) && (getEntry(j)->gen == 0))
>+        break;
>+    }
>+    if (j-i != 0)
>+    {
>+      Object obj;
>+      index.arrayAdd( obj.initInt(i) );
>+      index.arrayAdd( obj.initInt(j-i) );
>+      for (int k=i; k<j; k++) {
>+        XRefEntry *e = getEntry(k);
>+        if(e->gen > 65535) e->gen = 65535; //cap generation number to 65535 (required by PDFReference)
>+        char data[7];
>+        data[0] = (e->type==xrefEntryFree) ? 0 : 1;
>+        data[1] = (e->offset >> 24) & 0xff;
>+        data[2] = (e->offset >> 16) & 0xff;
>+        data[3] = (e->offset >> 8) & 0xff;
>+        data[4] = e->offset & 0xff;
>+        data[5] = (e->gen >> 8) & 0xff;
>+        data[6] = e->gen & 0xff;
>+        stmBuf->append(data, sizeof(data));
>+      }
>+      i = j;
>+    }
>+    else ++i;
>+  }
>+
>+  Object obj1, obj2;
>+  xrefDict->set("Type", obj1.initName("XRef"));
>+  xrefDict->set("Index", &index);
>+  obj2.initArray(xref);
>+  obj2.arrayAdd( obj1.initInt(1) );
>+  obj2.arrayAdd( obj1.initInt(4) );
>+  obj2.arrayAdd( obj1.initInt(2) );
>+  xrefDict->set("W", &obj2);
>+}
>+
> GBool XRef::parseEntry(Guint offset, XRefEntry *entry)
> {
>   GBool r;
>diff --git a/poppler/XRef.h b/poppler/XRef.h
>index 4cba474..15d0937 100644
>--- a/poppler/XRef.h
>+++ b/poppler/XRef.h
>@@ -79,6 +79,8 @@ public:
>   // Is xref table valid?
>   GBool isOk() { return ok; }
> 
>+  GBool isXRefStream() { return xRefStream; }
>+
>   // Get the error code (if isOk() returns false).
>   int getErrorCode() { return errCode; }
> 
>@@ -136,6 +138,7 @@ public:
>   void removeIndirectObject(Ref r);
>   void add(int num, int gen,  Guint offs, GBool used);
>   void writeToFile(OutStream* outStr, GBool writeAllEntries);
>+  void outputXRefStm(GooString *stmBuf, Dict *xrefDict, XRef *xref);
> 
> private:
> 
>-- 
>1.7.6.5
>

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