Make CFX_MemoryStream always consecutive.chromium/3524

Non-consecutive mode has questionable correctness and is not an obvious
performance win.

Change-Id: Idaa66e5ee5c4604628a0f55b67d5a04ab47ea5ec
Reviewed-on: https://pdfium-review.googlesource.com/40050
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

1 files changed, 5 insertions, 9 deletions

diff --git a/core/fxcrt/cfx_memorystream.h b/core/fxcrt/cfx_memorystream.h
index 95f62b6a2c..47e491275c 100644
--- a/core/fxcrt/cfx_memorystream.h
+++ b/core/fxcrt/cfx_memorystream.h
@@ -7,8 +7,9 @@
 #ifndef CORE_FXCRT_CFX_MEMORYSTREAM_H_
 #define CORE_FXCRT_CFX_MEMORYSTREAM_H_
 
-#include <vector>
+#include <memory>
 
+#include "core/fxcrt/fx_memory.h"
 #include "core/fxcrt/fx_stream.h"
 #include "core/fxcrt/retain_ptr.h"
 
@@ -26,24 +27,19 @@ class CFX_MemoryStream : public IFX_SeekableStream {
   bool WriteBlock(const void* buffer, FX_FILESIZE offset, size_t size) override;
   bool Flush() override;
 
-  uint8_t* GetBuffer() {
-    return !m_Blocks.empty() ? m_Blocks.front() : nullptr;
-  }
+  const uint8_t* GetBuffer() const { return m_data.get(); }
 
  private:
-  explicit CFX_MemoryStream(bool bConsecutive);
+  CFX_MemoryStream();
 
   // Takes ownership of |pBuffer|.
   CFX_MemoryStream(uint8_t* pBuffer, size_t nSize);
   ~CFX_MemoryStream() override;
 
-  bool ExpandBlocks(size_t size);
-
-  std::vector<uint8_t*> m_Blocks;
+  std::unique_ptr<uint8_t, FxFreeDeleter> m_data;
   size_t m_nTotalSize;
   size_t m_nCurSize;
   size_t m_nCurPos = 0;
-  const bool m_bConsecutive;
 };
 
 #endif  // CORE_FXCRT_CFX_MEMORYSTREAM_H_