1 files changed, 109 insertions, 0 deletions
diff --git a/core/fpdfapi/edit/cpdf_objectstream.cpp b/core/fpdfapi/edit/cpdf_objectstream.cpp
new file mode 100644
index 0000000000..e3f6e4c8e9
--- /dev/null
+++ b/core/fpdfapi/edit/cpdf_objectstream.cpp
@@ -0,0 +1,109 @@
+// Copyright 2017 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#include "core/fpdfapi/edit/cpdf_objectstream.h"
+
+#include "core/fpdfapi/edit/cpdf_creator.h"
+#include "core/fpdfapi/edit/cpdf_encryptor.h"
+#include "core/fpdfapi/edit/cpdf_flateencoder.h"
+#include "core/fpdfapi/parser/fpdf_parser_utility.h"
+
+namespace {
+
+const int kObjectStreamMaxLength = 256 * 1024;
+
+}  // namespace
+
+CPDF_ObjectStream::CPDF_ObjectStream() : m_dwObjNum(0), m_index(0) {}
+
+CPDF_ObjectStream::~CPDF_ObjectStream() {}
+
+bool CPDF_ObjectStream::IsNotFull() const {
+  return m_Buffer.GetLength() < kObjectStreamMaxLength;
+}
+
+void CPDF_ObjectStream::Start() {
+  m_Items.clear();
+  m_Buffer.Clear();
+  m_dwObjNum = 0;
+  m_index = 0;
+}
+
+void CPDF_ObjectStream::CompressIndirectObject(uint32_t dwObjNum,
+                                               const CPDF_Object* pObj) {
+  m_Items.push_back({dwObjNum, m_Buffer.GetLength()});
+  m_Buffer << pObj;
+}
+
+void CPDF_ObjectStream::CompressIndirectObject(uint32_t dwObjNum,
+                                               const uint8_t* pBuffer,
+                                               uint32_t dwSize) {
+  m_Items.push_back({dwObjNum, m_Buffer.GetLength()});
+  m_Buffer.AppendBlock(pBuffer, dwSize);
+}
+
+FX_FILESIZE CPDF_ObjectStream::End(CPDF_Creator* pCreator) {
+  ASSERT(pCreator);
+  if (m_Items.empty())
+    return 0;
+
+  CFX_FileBufferArchive* pFile = pCreator->GetFile();
+  FX_FILESIZE ObjOffset = pCreator->GetOffset();
+  if (!m_dwObjNum)
+    m_dwObjNum = pCreator->GetNextObjectNumber();
+
+  CFX_ByteTextBuf tempBuffer;
+  for (const auto& pair : m_Items)
+    tempBuffer << pair.objnum << " " << pair.offset << " ";
+
+  int32_t len = pFile->AppendDWord(m_dwObjNum);
+  if (len < 0)
+    return -1;
+
+  pCreator->IncrementOffset(len);
+  if ((len = pFile->AppendString(" 0 obj\r\n<</Type /ObjStm /N ")) < 0)
+    return -1;
+
+  pCreator->IncrementOffset(len);
+  uint32_t iCount = pdfium::CollectionSize<uint32_t>(m_Items);
+  if ((len = pFile->AppendDWord(iCount)) < 0)
+    return -1;
+
+  pCreator->IncrementOffset(len);
+  if (pFile->AppendString("/First ") < 0)
+    return -1;
+  if ((len = pFile->AppendDWord((uint32_t)tempBuffer.GetLength())) < 0)
+    return -1;
+  if (pFile->AppendString("/Length ") < 0)
+    return -1;
+
+  pCreator->IncrementOffset(len + 15);
+
+  tempBuffer << m_Buffer;
+  CPDF_FlateEncoder encoder(tempBuffer.GetBuffer(), tempBuffer.GetLength(),
+                            true, false);
+  CPDF_Encryptor encryptor(pCreator->GetCryptoHandler(), m_dwObjNum,
+                           encoder.GetData(), encoder.GetSize());
+  if ((len = pFile->AppendDWord(encryptor.GetSize())) < 0)
+    return -1;
+
+  pCreator->IncrementOffset(len);
+  if (pFile->AppendString("/Filter /FlateDecode") < 0)
+    return -1;
+
+  pCreator->IncrementOffset(20);
+  if ((len = pFile->AppendString(">>stream\r\n")) < 0)
+    return -1;
+  if (pFile->AppendBlock(encryptor.GetData(), encryptor.GetSize()) < 0)
+    return -1;
+
+  pCreator->IncrementOffset(len + encryptor.GetSize());
+  if ((len = pFile->AppendString("\r\nendstream\r\nendobj\r\n")) < 0)
+    return -1;
+
+  pCreator->IncrementOffset(len);
+  return ObjOffset;
+}