Code change to avoid signed/unsigned mismatch warnings.

This makes pdfium code on Linux and Mac sign-compare warning free.
The warning flag will be re-enabled after checking on windows clang build.

BUG=pdfium:29
R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1841643002 .

5 files changed, 16 insertions, 11 deletions

diff --git a/core/fpdfapi/fpdf_parser/cpdf_array.cpp b/core/fpdfapi/fpdf_parser/cpdf_array.cpp
index 7ea2734745..964ba64236 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_array.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_array.cpp
@@ -131,14 +131,14 @@ CPDF_Array* CPDF_Array::GetArrayAt(uint32_t i) const {
   return ToArray(GetDirectObjectAt(i));
 }
 
-void CPDF_Array::RemoveAt(uint32_t i, int nCount) {
+void CPDF_Array::RemoveAt(uint32_t i, uint32_t nCount) {
   if (i >= (uint32_t)m_Objects.GetSize())
     return;
 
   if (nCount <= 0 || nCount > m_Objects.GetSize() - i)
     return;
 
-  for (int j = 0; j < nCount; ++j) {
+  for (uint32_t j = 0; j < nCount; ++j) {
     if (CPDF_Object* p = m_Objects.GetAt(i + j))
       p->Release();
   }
diff --git a/core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp b/core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp
index d81725d06f..18687e5fb7 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp
@@ -59,7 +59,7 @@ FX_BOOL CPDF_HintTables::ReadPageHintTable(CFX_BitStream* hStream) {
 
   // Item 2: The location of the first page's page object.
   uint32_t dwFirstObjLoc = hStream->GetBits(32);
-  if (dwFirstObjLoc > nStreamOffset) {
+  if (dwFirstObjLoc > static_cast<uint32_t>(nStreamOffset)) {
     FX_SAFE_DWORD safeLoc = pdfium::base::checked_cast<uint32_t>(nStreamLen);
     safeLoc += dwFirstObjLoc;
     if (!safeLoc.IsValid())
@@ -236,7 +236,7 @@ FX_BOOL CPDF_HintTables::ReadSharedObjHintTable(CFX_BitStream* hStream,
 
   // Item 2: The location of the first object in the shared objects section.
   uint32_t dwFirstSharedObjLoc = hStream->GetBits(32);
-  if (dwFirstSharedObjLoc > nStreamOffset)
+  if (dwFirstSharedObjLoc > static_cast<uint32_t>(nStreamOffset))
     dwFirstSharedObjLoc += nStreamLen;
 
   // Item 3: The number of shared object entries for the first page.
@@ -387,12 +387,13 @@ IPDF_DataAvail::DocAvailStatus CPDF_HintTables::CheckPage(
   uint32_t dwObjNum = 0;
   for (uint32_t j = 0; j < m_dwNSharedObjsArray[index]; ++j) {
     dwIndex = m_dwIdentifierArray[offset + j];
-    if (dwIndex >= m_dwSharedObjNumArray.GetSize())
+    if (dwIndex >= static_cast<uint32_t>(m_dwSharedObjNumArray.GetSize()))
       return IPDF_DataAvail::DataNotAvailable;
 
     dwObjNum = m_dwSharedObjNumArray[dwIndex];
-    if (dwObjNum >= nFirstPageObjNum &&
-        dwObjNum < nFirstPageObjNum + m_nFirstPageSharedObjs) {
+    if (dwObjNum >= static_cast<uint32_t>(nFirstPageObjNum) &&
+        dwObjNum <
+            static_cast<uint32_t>(nFirstPageObjNum) + m_nFirstPageSharedObjs) {
       continue;
     }
 
@@ -428,7 +429,7 @@ FX_BOOL CPDF_HintTables::LoadHintStream(CPDF_Stream* pHintStream) {
   // Hint table has at least 60 bytes.
   const uint32_t MIN_STREAM_LEN = 60;
   if (size < MIN_STREAM_LEN || shared_hint_table_offset <= 0 ||
-      size < shared_hint_table_offset) {
+      size < static_cast<uint32_t>(shared_hint_table_offset)) {
     return FALSE;
   }
 
diff --git a/core/fpdfapi/fpdf_parser/cpdf_indirect_object_holder.cpp b/core/fpdfapi/fpdf_parser/cpdf_indirect_object_holder.cpp
index 14410dabb5..ef3395d3ae 100644
--- a/core/fpdfapi/fpdf_parser/cpdf_indirect_object_holder.cpp
+++ b/core/fpdfapi/fpdf_parser/cpdf_indirect_object_holder.cpp
@@ -26,7 +26,8 @@ CPDF_Object* CPDF_IndirectObjectHolder::GetIndirectObject(uint32_t objnum) {
 
   auto it = m_IndirectObjs.find(objnum);
   if (it != m_IndirectObjs.end())
-    return it->second->GetObjNum() != -1 ? it->second : nullptr;
+    return it->second->GetObjNum() != CPDF_Object::kInvalidObjNum ? it->second
+                                                                  : nullptr;
 
   if (!m_pParser)
     return nullptr;
@@ -56,8 +57,10 @@ uint32_t CPDF_IndirectObjectHolder::AddIndirectObject(CPDF_Object* pObj) {
 
 void CPDF_IndirectObjectHolder::ReleaseIndirectObject(uint32_t objnum) {
   auto it = m_IndirectObjs.find(objnum);
-  if (it == m_IndirectObjs.end() || it->second->GetObjNum() == -1)
+  if (it == m_IndirectObjs.end() ||
+      it->second->GetObjNum() == CPDF_Object::kInvalidObjNum) {
     return;
+  }
   it->second->Destroy();
   m_IndirectObjs.erase(it);
 }
diff --git a/core/fpdfapi/fpdf_parser/include/cpdf_array.h b/core/fpdfapi/fpdf_parser/include/cpdf_array.h
index ea367785ed..b964f4955b 100644
--- a/core/fpdfapi/fpdf_parser/include/cpdf_array.h
+++ b/core/fpdfapi/fpdf_parser/include/cpdf_array.h
@@ -44,7 +44,7 @@ class CPDF_Array : public CPDF_Object {
   void InsertAt(uint32_t index,
                 CPDF_Object* pObj,
                 CPDF_IndirectObjectHolder* pObjs = nullptr);
-  void RemoveAt(uint32_t index, int nCount = 1);
+  void RemoveAt(uint32_t index, uint32_t nCount = 1);
 
   void Add(CPDF_Object* pObj, CPDF_IndirectObjectHolder* pObjs = nullptr);
   void AddNumber(FX_FLOAT f);
diff --git a/core/fpdfapi/fpdf_parser/include/cpdf_object.h b/core/fpdfapi/fpdf_parser/include/cpdf_object.h
index 1ba38a946e..802cbbc638 100644
--- a/core/fpdfapi/fpdf_parser/include/cpdf_object.h
+++ b/core/fpdfapi/fpdf_parser/include/cpdf_object.h
@@ -22,6 +22,7 @@ class CPDF_String;
 
 class CPDF_Object {
  public:
+  static const uint32_t kInvalidObjNum = static_cast<uint32_t>(-1);
   enum Type {
     BOOLEAN = 1,
     NUMBER,