Fix hint tables parsing.

Sample PDF:
https://yadi.sk/d/oWLtAEfy3YbEb3

For offsets, equal to the hint stream offset, added hint stream
length to determine the actual offset, because linearization
inserted the hint stream at the original location of the object.

Also the number of bits needed to represent the numerator of
the fractional position for each shared object reference may be
zero, if each shared group contains only one object with obj num,
incremented on 1.

Change-Id: I4754d603f388354821e8d0cac97ad99a7578fe4b
Reviewed-on: https://pdfium-review.googlesource.com/36610
Commit-Queue: Art Snake <art-snake@yandex-team.ru>
Reviewed-by: Lei Zhang <thestig@chromium.org>

1 files changed, 59 insertions, 5 deletions

diff --git a/core/fpdfapi/parser/cpdf_hint_tables_unittest.cpp b/core/fpdfapi/parser/cpdf_hint_tables_unittest.cpp
index af0e9ff745..8a7331d29b 100644
--- a/core/fpdfapi/parser/cpdf_hint_tables_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_hint_tables_unittest.cpp
@@ -10,9 +10,14 @@
 
 #include "core/fpdfapi/cpdf_modulemgr.h"
 #include "core/fpdfapi/parser/cpdf_data_avail.h"
+#include "core/fpdfapi/parser/cpdf_dictionary.h"
+#include "core/fpdfapi/parser/cpdf_linearized_header.h"
 #include "core/fpdfapi/parser/cpdf_object.h"
+#include "core/fpdfapi/parser/cpdf_read_validator.h"
+#include "core/fpdfapi/parser/cpdf_stream.h"
 #include "core/fpdfapi/parser/cpdf_syntax_parser.h"
 #include "core/fxcrt/fx_stream.h"
+#include "testing/fx_string_testhelpers.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/utils/path_service.h"
@@ -20,16 +25,42 @@
 
 namespace {
 
-std::unique_ptr<CPDF_DataAvail> MakeDataAvailFromFile(
+RetainPtr<CPDF_ReadValidator> MakeValidatorFromFile(
     const std::string& file_name) {
   std::string file_path;
-  if (!PathService::GetTestFilePath(file_name, &file_path))
-    return nullptr;
+  PathService::GetTestFilePath(file_name, &file_path);
+  ASSERT(!file_path.empty());
+  return pdfium::MakeRetain<CPDF_ReadValidator>(
+      IFX_SeekableReadStream::CreateFromFilename(file_path.c_str()), nullptr);
+}
+
+std::unique_ptr<CPDF_DataAvail> MakeDataAvailFromFile(
+    const std::string& file_name) {
   return pdfium::MakeUnique<CPDF_DataAvail>(
-      nullptr, IFX_SeekableReadStream::CreateFromFilename(file_path.c_str()),
-      true);
+      nullptr, MakeValidatorFromFile(file_name), true);
 }
 
+class TestLinearizedHeader : public CPDF_LinearizedHeader {
+ public:
+  TestLinearizedHeader(const CPDF_Dictionary* pDict,
+                       FX_FILESIZE szLastXRefOffset)
+      : CPDF_LinearizedHeader(pDict, szLastXRefOffset) {}
+
+  static std::unique_ptr<CPDF_LinearizedHeader> MakeHeader(
+      const std::string& inline_data) {
+    CPDF_SyntaxParser parser;
+    parser.InitParser(
+        pdfium::MakeRetain<CFX_BufferSeekableReadStream>(
+            reinterpret_cast<const unsigned char*>(inline_data.data()),
+            inline_data.size()),
+        0);
+    std::unique_ptr<CPDF_Dictionary> dict =
+        ToDictionary(parser.GetObjectBody(nullptr));
+    ASSERT(dict);
+    return pdfium::MakeUnique<TestLinearizedHeader>(dict.get(), 0);
+  }
+};
+
 }  // namespace
 
 class CPDF_HintTablesTest : public testing::Test {
@@ -119,3 +150,26 @@ TEST_F(CPDF_HintTablesTest, PageAndGroupInfos) {
   EXPECT_EQ(10939, hint_tables->SharedGroupInfos()[5].m_szOffset);
   EXPECT_EQ(544u, hint_tables->SharedGroupInfos()[5].m_dwLength);
 }
+
+TEST_F(CPDF_HintTablesTest, FirstPageOffset) {
+  // Test that valid hint table is loaded, and have correct offset of first page
+  // object.
+  const auto linearized_header = TestLinearizedHeader::MakeHeader(
+      "<< /Linearized 1 /L 19326762 /H [ 123730 3816 ] /O 5932 /E 639518 /N "
+      "102 /T 19220281 >>");
+  ASSERT_TRUE(linearized_header);
+  // This hint table is extracted from linearized file, generated by qpdf tool.
+  RetainPtr<CPDF_ReadValidator> validator =
+      MakeValidatorFromFile("hint_table_102p.bin");
+  CPDF_SyntaxParser parser;
+  parser.InitParserWithValidator(validator, 0);
+  std::unique_ptr<CPDF_Stream> stream = ToStream(parser.GetObjectBody(nullptr));
+  ASSERT_TRUE(stream);
+  auto hint_tables = pdfium::MakeUnique<CPDF_HintTables>(
+      validator.Get(), linearized_header.get());
+  // Check that hint table will load.
+  ASSERT_TRUE(hint_tables->LoadHintStream(stream.get()));
+  // Check that hint table have correct first page offset.
+  // 127546 is predefined real value from original file.
+  EXPECT_EQ(127546, hint_tables->GetFirstPageObjOffset());
+}