Use document size instead of file size while parsing.

We should use document size instead of File size,
because all offsets and sizes was read from document should
take into account of header offset.

Added some tests of parsing of documents with header offset.
Also drop friendship of CPDF_SyntaxParser with CPDF_Parser.

Change-Id: Iebec75ab2ee07fb644a6c653b4ef5c2e09af09fe
Reviewed-on: https://pdfium-review.googlesource.com/35830
Commit-Queue: Art Snake <art-snake@yandex-team.ru>
Reviewed-by: Lei Zhang <thestig@chromium.org>

1 files changed, 7 insertions, 7 deletions

diff --git a/core/fpdfapi/edit/cpdf_creator.cpp b/core/fpdfapi/edit/cpdf_creator.cpp
index aa8c751046..11b0628b01 100644
--- a/core/fpdfapi/edit/cpdf_creator.cpp
+++ b/core/fpdfapi/edit/cpdf_creator.cpp
@@ -17,6 +17,7 @@
 #include "core/fpdfapi/parser/cpdf_parser.h"
 #include "core/fpdfapi/parser/cpdf_security_handler.h"
 #include "core/fpdfapi/parser/cpdf_string.h"
+#include "core/fpdfapi/parser/cpdf_syntax_parser.h"
 #include "core/fpdfapi/parser/fpdf_parser_decode.h"
 #include "core/fpdfapi/parser/fpdf_parser_utility.h"
 #include "core/fxcrt/fx_extension.h"
@@ -254,20 +255,19 @@ CPDF_Creator::Stage CPDF_Creator::WriteDoc_Stage1() {
       }
       m_iStage = Stage::kInitWriteObjs20;
     } else {
-      m_SavedOffset = m_pParser->GetFileAccess()->GetSize();
+      m_SavedOffset = m_pParser->GetSyntax()->GetDocumentSize();
       m_iStage = Stage::kWriteIncremental15;
     }
   }
   if (m_iStage == Stage::kWriteIncremental15) {
     if (m_IsOriginal && m_SavedOffset > 0) {
-      RetainPtr<IFX_SeekableReadStream> pSrcFile = m_pParser->GetFileAccess();
-      std::vector<uint8_t> buffer(4096);
+      static constexpr FX_FILESIZE kBufferSize = 4096;
+      std::vector<uint8_t> buffer(kBufferSize);
       FX_FILESIZE src_size = m_SavedOffset;
+      m_pParser->GetSyntax()->SetPos(0);
       while (src_size) {
-        uint32_t block_size = src_size > 4096 ? 4096 : src_size;
-        if (!pSrcFile->ReadBlock(buffer.data(),
-                                 m_Archive->CurrentOffset() - src_size,
-                                 block_size)) {
+        const FX_FILESIZE block_size = std::min(kBufferSize, src_size);
+        if (!m_pParser->GetSyntax()->ReadBlock(buffer.data(), block_size)) {
           return Stage::kInvalid;
         }
         if (!m_Archive->WriteBlock(buffer.data(), block_size))