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 .

34 files changed, 265 insertions, 308 deletions

diff --git a/core/fpdfapi/fpdf_cmaps/fpdf_cmaps.cpp b/core/fpdfapi/fpdf_cmaps/fpdf_cmaps.cpp
index 3cd6106e1c..9248efb718 100644
--- a/core/fpdfapi/fpdf_cmaps/fpdf_cmaps.cpp
+++ b/core/fpdfapi/fpdf_cmaps/fpdf_cmaps.cpp
@@ -18,11 +18,10 @@ void FPDFAPI_FindEmbeddedCMap(const char* name,
       CPDF_ModuleMgr::Get()->GetPageModule()->GetFontGlobals();
   const FXCMAP_CMap* pCMaps =
       pFontGlobals->m_EmbeddedCharsets[charset].m_pMapList;
-  int nCMaps = pFontGlobals->m_EmbeddedCharsets[charset].m_Count;
-  for (int i = 0; i < nCMaps; i++) {
-    if (FXSYS_strcmp(name, pCMaps[i].m_Name)) {
+  for (uint32_t i = 0; i < pFontGlobals->m_EmbeddedCharsets[charset].m_Count;
+       i++) {
+    if (FXSYS_strcmp(name, pCMaps[i].m_Name))
       continue;
-    }
     pMap = &pCMaps[i];
     break;
   }
diff --git a/core/fpdfapi/fpdf_edit/fpdf_edit_create.cpp b/core/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
index 0f087d980a..21934d35c4 100644
--- a/core/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
+++ b/core/fpdfapi/fpdf_edit/fpdf_edit_create.cpp
@@ -1410,7 +1410,7 @@ void CPDF_Creator::InitNewObjNumOffsets() {
   for (const auto& pair : m_pDocument->m_IndirectObjs) {
     const uint32_t objnum = pair.first;
     const CPDF_Object* pObj = pair.second;
-    if (pObj->GetObjNum() == -1)
+    if (pObj->GetObjNum() == CPDF_Object::kInvalidObjNum)
       continue;
     if (bIncremental) {
       if (!pObj->IsModified())
diff --git a/core/fpdfapi/fpdf_font/cpdf_cidfont.cpp b/core/fpdfapi/fpdf_font/cpdf_cidfont.cpp
index de119b75d1..3329f5c577 100644
--- a/core/fpdfapi/fpdf_font/cpdf_cidfont.cpp
+++ b/core/fpdfapi/fpdf_font/cpdf_cidfont.cpp
@@ -155,13 +155,12 @@ uint32_t EmbeddedCharcodeFromUnicode(const FXCMAP_CMap* pEmbedMap,
   if (!pCodes)
     return 0;
 
-  int nCodes = pFontGlobals->m_EmbeddedToUnicodes[charset].m_Count;
-  for (int i = 0; i < nCodes; ++i) {
+  for (uint32_t i = 0; i < pFontGlobals->m_EmbeddedToUnicodes[charset].m_Count;
+       ++i) {
     if (pCodes[i] == unicode) {
       uint32_t CharCode = FPDFAPI_CharCodeFromCID(pEmbedMap, i);
-      if (CharCode != 0) {
+      if (CharCode != 0)
         return CharCode;
-      }
     }
   }
   return 0;
diff --git a/core/fpdfapi/fpdf_font/font_int.h b/core/fpdfapi/fpdf_font/font_int.h
index 3ee4068d7d..fc69b0cbd9 100644
--- a/core/fpdfapi/fpdf_font/font_int.h
+++ b/core/fpdfapi/fpdf_font/font_int.h
@@ -48,8 +48,8 @@ class CFX_StockFontArray {
   ~CFX_StockFontArray();
 
   // Takes ownership of |pFont|.
-  void SetFont(int index, CPDF_Font* pFont);
-  CPDF_Font* GetFont(int index) const;
+  void SetFont(uint32_t index, CPDF_Font* pFont);
+  CPDF_Font* GetFont(uint32_t index) const;
 
  private:
   std::unique_ptr<CPDF_Font> m_StockFonts[14];
@@ -61,19 +61,19 @@ class CPDF_FontGlobals {
   ~CPDF_FontGlobals();
 
   void Clear(CPDF_Document* pDoc);
-  CPDF_Font* Find(CPDF_Document* pDoc, int index);
+  CPDF_Font* Find(CPDF_Document* pDoc, uint32_t index);
 
   // Takes ownership of |pFont|.
-  void Set(CPDF_Document* key, int index, CPDF_Font* pFont);
+  void Set(CPDF_Document* key, uint32_t index, CPDF_Font* pFont);
 
   CPDF_CMapManager m_CMapManager;
   struct {
     const struct FXCMAP_CMap* m_pMapList;
-    int m_Count;
+    uint32_t m_Count;
   } m_EmbeddedCharsets[CIDSET_NUM_SETS];
   struct {
     const uint16_t* m_pMap;
-    int m_Count;
+    uint32_t m_Count;
   } m_EmbeddedToUnicodes[CIDSET_NUM_SETS];
 
  private:
diff --git a/core/fpdfapi/fpdf_font/fpdf_font.cpp b/core/fpdfapi/fpdf_font/fpdf_font.cpp
index b0659b4a52..ce2390ec08 100644
--- a/core/fpdfapi/fpdf_font/fpdf_font.cpp
+++ b/core/fpdfapi/fpdf_font/fpdf_font.cpp
@@ -45,14 +45,14 @@ CFX_StockFontArray::~CFX_StockFontArray() {
   }
 }
 
-CPDF_Font* CFX_StockFontArray::GetFont(int index) const {
-  if (index < 0 || index >= FX_ArraySize(m_StockFonts))
+CPDF_Font* CFX_StockFontArray::GetFont(uint32_t index) const {
+  if (index >= FX_ArraySize(m_StockFonts))
     return nullptr;
   return m_StockFonts[index].get();
 }
 
-void CFX_StockFontArray::SetFont(int index, CPDF_Font* font) {
-  if (index < 0 || index >= FX_ArraySize(m_StockFonts))
+void CFX_StockFontArray::SetFont(uint32_t index, CPDF_Font* font) {
+  if (index >= FX_ArraySize(m_StockFonts))
     return;
   m_StockFonts[index].reset(font);
 }
@@ -64,14 +64,16 @@ CPDF_FontGlobals::CPDF_FontGlobals() {
 
 CPDF_FontGlobals::~CPDF_FontGlobals() {}
 
-CPDF_Font* CPDF_FontGlobals::Find(CPDF_Document* pDoc, int index) {
+CPDF_Font* CPDF_FontGlobals::Find(CPDF_Document* pDoc, uint32_t index) {
   auto it = m_StockMap.find(pDoc);
   if (it == m_StockMap.end())
     return nullptr;
   return it->second ? it->second->GetFont(index) : nullptr;
 }
 
-void CPDF_FontGlobals::Set(CPDF_Document* pDoc, int index, CPDF_Font* pFont) {
+void CPDF_FontGlobals::Set(CPDF_Document* pDoc,
+                           uint32_t index,
+                           CPDF_Font* pFont) {
   if (!pdfium::ContainsKey(m_StockMap, pDoc))
     m_StockMap[pDoc].reset(new CFX_StockFontArray);
   m_StockMap[pDoc]->SetFont(index, pFont);
@@ -121,7 +123,7 @@ CFX_WideString CPDF_ToUnicodeMap::Lookup(uint32_t charcode) {
 
 uint32_t CPDF_ToUnicodeMap::ReverseLookup(FX_WCHAR unicode) {
   for (const auto& pair : m_Map) {
-    if (pair.second == unicode)
+    if (pair.second == static_cast<uint32_t>(unicode))
       return pair.first;
   }
   return 0;
diff --git a/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp b/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp
index c12b9c5eee..ccf49ee46a 100644
--- a/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp
+++ b/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp
@@ -18,16 +18,16 @@ bool uint_ranges_equal(uint8_t* a, uint8_t* b, size_t count) {
 }  // namespace
 
 TEST(fpdf_font_cid, CMap_GetCode) {
-  EXPECT_EQ(0, CPDF_CMapParser::CMap_GetCode(""));
-  EXPECT_EQ(0, CPDF_CMapParser::CMap_GetCode("<"));
-  EXPECT_EQ(194, CPDF_CMapParser::CMap_GetCode("<c2"));
-  EXPECT_EQ(162, CPDF_CMapParser::CMap_GetCode("<A2"));
-  EXPECT_EQ(2802, CPDF_CMapParser::CMap_GetCode("<Af2"));
-  EXPECT_EQ(162, CPDF_CMapParser::CMap_GetCode("<A2z"));
+  EXPECT_EQ(0u, CPDF_CMapParser::CMap_GetCode(""));
+  EXPECT_EQ(0u, CPDF_CMapParser::CMap_GetCode("<"));
+  EXPECT_EQ(194u, CPDF_CMapParser::CMap_GetCode("<c2"));
+  EXPECT_EQ(162u, CPDF_CMapParser::CMap_GetCode("<A2"));
+  EXPECT_EQ(2802u, CPDF_CMapParser::CMap_GetCode("<Af2"));
+  EXPECT_EQ(162u, CPDF_CMapParser::CMap_GetCode("<A2z"));
 
-  EXPECT_EQ(12, CPDF_CMapParser::CMap_GetCode("12"));
-  EXPECT_EQ(12, CPDF_CMapParser::CMap_GetCode("12d"));
-  EXPECT_EQ(128, CPDF_CMapParser::CMap_GetCode("128"));
+  EXPECT_EQ(12u, CPDF_CMapParser::CMap_GetCode("12"));
+  EXPECT_EQ(12u, CPDF_CMapParser::CMap_GetCode("12d"));
+  EXPECT_EQ(128u, CPDF_CMapParser::CMap_GetCode("128"));
 }
 
 TEST(fpdf_font_cid, CMap_GetCodeRange) {
diff --git a/core/fpdfapi/fpdf_font/fpdf_font_unittest.cpp b/core/fpdfapi/fpdf_font/fpdf_font_unittest.cpp
index dd2119e0cf..0c5ad8a66a 100644
--- a/core/fpdfapi/fpdf_font/fpdf_font_unittest.cpp
+++ b/core/fpdfapi/fpdf_font/fpdf_font_unittest.cpp
@@ -6,12 +6,12 @@
 #include "testing/gtest/include/gtest/gtest.h"
 
 TEST(fpdf_font, StringToCode) {
-  EXPECT_EQ(0, CPDF_ToUnicodeMap::StringToCode(""));
-  EXPECT_EQ(194, CPDF_ToUnicodeMap::StringToCode("<c2"));
-  EXPECT_EQ(162, CPDF_ToUnicodeMap::StringToCode("<A2"));
-  EXPECT_EQ(2802, CPDF_ToUnicodeMap::StringToCode("<Af2"));
-  EXPECT_EQ(12, CPDF_ToUnicodeMap::StringToCode("12"));
-  EXPECT_EQ(128, CPDF_ToUnicodeMap::StringToCode("128"));
+  EXPECT_EQ(0u, CPDF_ToUnicodeMap::StringToCode(""));
+  EXPECT_EQ(194u, CPDF_ToUnicodeMap::StringToCode("<c2"));
+  EXPECT_EQ(162u, CPDF_ToUnicodeMap::StringToCode("<A2"));
+  EXPECT_EQ(2802u, CPDF_ToUnicodeMap::StringToCode("<Af2"));
+  EXPECT_EQ(12u, CPDF_ToUnicodeMap::StringToCode("12"));
+  EXPECT_EQ(128u, CPDF_ToUnicodeMap::StringToCode("128"));
 }
 
 TEST(fpdf_font, StringToWideString) {
diff --git a/core/fpdfapi/fpdf_page/cpdf_colorstate.cpp b/core/fpdfapi/fpdf_page/cpdf_colorstate.cpp
index 7f80c82a03..5c73b28e67 100644
--- a/core/fpdfapi/fpdf_page/cpdf_colorstate.cpp
+++ b/core/fpdfapi/fpdf_page/cpdf_colorstate.cpp
@@ -12,14 +12,14 @@
 
 void CPDF_ColorState::SetFillColor(CPDF_ColorSpace* pCS,
                                    FX_FLOAT* pValue,
-                                   int nValues) {
+                                   uint32_t nValues) {
   CPDF_ColorStateData* pData = GetModify();
   SetColor(pData->m_FillColor, pData->m_FillRGB, pCS, pValue, nValues);
 }
 
 void CPDF_ColorState::SetStrokeColor(CPDF_ColorSpace* pCS,
                                      FX_FLOAT* pValue,
-                                     int nValues) {
+                                     uint32_t nValues) {
   CPDF_ColorStateData* pData = GetModify();
   SetColor(pData->m_StrokeColor, pData->m_StrokeRGB, pCS, pValue, nValues);
 }
@@ -28,7 +28,7 @@ void CPDF_ColorState::SetColor(CPDF_Color& color,
                                uint32_t& rgb,
                                CPDF_ColorSpace* pCS,
                                FX_FLOAT* pValue,
-                               int nValues) {
+                               uint32_t nValues) {
   if (pCS) {
     color.SetColorSpace(pCS);
   } else if (color.IsNull()) {
@@ -44,7 +44,7 @@ void CPDF_ColorState::SetColor(CPDF_Color& color,
 
 void CPDF_ColorState::SetFillPattern(CPDF_Pattern* pPattern,
                                      FX_FLOAT* pValue,
-                                     int nValues) {
+                                     uint32_t nValues) {
   CPDF_ColorStateData* pData = GetModify();
   pData->m_FillColor.SetValue(pPattern, pValue, nValues);
   int R, G, B;
@@ -59,7 +59,7 @@ void CPDF_ColorState::SetFillPattern(CPDF_Pattern* pPattern,
 
 void CPDF_ColorState::SetStrokePattern(CPDF_Pattern* pPattern,
                                        FX_FLOAT* pValue,
-                                       int nValues) {
+                                       uint32_t nValues) {
   CPDF_ColorStateData* pData = GetModify();
   pData->m_StrokeColor.SetValue(pPattern, pValue, nValues);
   int R, G, B;
diff --git a/core/fpdfapi/fpdf_page/cpdf_colorstate.h b/core/fpdfapi/fpdf_page/cpdf_colorstate.h
index 2b27d07702..da4c49d3c9 100644
--- a/core/fpdfapi/fpdf_page/cpdf_colorstate.h
+++ b/core/fpdfapi/fpdf_page/cpdf_colorstate.h
@@ -25,17 +25,21 @@ class CPDF_ColorState : public CFX_CountRef<CPDF_ColorStateData> {
     return m_pObject ? &m_pObject->m_StrokeColor : nullptr;
   }
 
-  void SetFillColor(CPDF_ColorSpace* pCS, FX_FLOAT* pValue, int nValues);
-  void SetStrokeColor(CPDF_ColorSpace* pCS, FX_FLOAT* pValue, int nValues);
-  void SetFillPattern(CPDF_Pattern* pattern, FX_FLOAT* pValue, int nValues);
-  void SetStrokePattern(CPDF_Pattern* pattern, FX_FLOAT* pValue, int nValues);
+  void SetFillColor(CPDF_ColorSpace* pCS, FX_FLOAT* pValue, uint32_t nValues);
+  void SetStrokeColor(CPDF_ColorSpace* pCS, FX_FLOAT* pValue, uint32_t nValues);
+  void SetFillPattern(CPDF_Pattern* pattern,
+                      FX_FLOAT* pValue,
+                      uint32_t nValues);
+  void SetStrokePattern(CPDF_Pattern* pattern,
+                        FX_FLOAT* pValue,
+                        uint32_t nValues);
 
  private:
   void SetColor(CPDF_Color& color,
                 uint32_t& rgb,
                 CPDF_ColorSpace* pCS,
                 FX_FLOAT* pValue,
-                int nValues);
+                uint32_t nValues);
 };
 
 #endif  // CORE_FPDFAPI_FPDF_PAGE_CPDF_COLORSTATE_H_
diff --git a/core/fpdfapi/fpdf_page/cpdf_shadingpattern.cpp b/core/fpdfapi/fpdf_page/cpdf_shadingpattern.cpp
index 4ca9acbea7..f637a4463c 100644
--- a/core/fpdfapi/fpdf_page/cpdf_shadingpattern.cpp
+++ b/core/fpdfapi/fpdf_page/cpdf_shadingpattern.cpp
@@ -43,7 +43,7 @@ CPDF_ShadingPattern::CPDF_ShadingPattern(CPDF_Document* pDoc,
     if (parentMatrix)
       m_Pattern2Form.Concat(*parentMatrix);
   }
-  for (int i = 0; i < FX_ArraySize(m_pFunctions); ++i)
+  for (size_t i = 0; i < FX_ArraySize(m_pFunctions); ++i)
     m_pFunctions[i] = nullptr;
 }
 
diff --git a/core/fpdfapi/fpdf_page/fpdf_page_func.cpp b/core/fpdfapi/fpdf_page/fpdf_page_func.cpp
index 7d396ed032..ebd6811da8 100644
--- a/core/fpdfapi/fpdf_page/fpdf_page_func.cpp
+++ b/core/fpdfapi/fpdf_page/fpdf_page_func.cpp
@@ -116,7 +116,7 @@ class CPDF_PSProc {
   std::vector<std::unique_ptr<CPDF_PSOP>> m_Operators;
 };
 
-const size_t PSENGINE_STACKSIZE = 100;
+const uint32_t PSENGINE_STACKSIZE = 100;
 
 class CPDF_PSEngine {
  public:
@@ -130,11 +130,11 @@ class CPDF_PSEngine {
   void Push(FX_FLOAT value);
   void Push(int value) { Push((FX_FLOAT)value); }
   FX_FLOAT Pop();
-  int GetStackSize() const { return m_StackCount; }
+  uint32_t GetStackSize() const { return m_StackCount; }
 
  private:
   FX_FLOAT m_Stack[PSENGINE_STACKSIZE];
-  int m_StackCount;
+  uint32_t m_StackCount;
   CPDF_PSProc m_MainProc;
 };
 
@@ -430,49 +430,42 @@ FX_BOOL CPDF_PSEngine::DoOperator(PDF_PSOP op) {
       Push(d1);
       break;
     case PSOP_COPY: {
-      int n = (int)Pop();
-      if (n < 0 || n > PSENGINE_STACKSIZE ||
-          m_StackCount + n > PSENGINE_STACKSIZE || n > m_StackCount) {
+      int n = static_cast<int>(Pop());
+      if (n < 0 || m_StackCount + n > PSENGINE_STACKSIZE ||
+          n > static_cast<int>(m_StackCount))
         break;
-      }
-      for (int i = 0; i < n; i++) {
+      for (int i = 0; i < n; i++)
         m_Stack[m_StackCount + i] = m_Stack[m_StackCount + i - n];
-      }
       m_StackCount += n;
       break;
     }
     case PSOP_INDEX: {
-      int n = (int)Pop();
-      if (n < 0 || n >= m_StackCount) {
+      int n = static_cast<int>(Pop());
+      if (n < 0 || n >= static_cast<int>(m_StackCount))
         break;
-      }
       Push(m_Stack[m_StackCount - n - 1]);
       break;
     }
     case PSOP_ROLL: {
-      int j = (int)Pop();
-      int n = (int)Pop();
-      if (m_StackCount == 0) {
+      int j = static_cast<int>(Pop());
+      int n = static_cast<int>(Pop());
+      if (m_StackCount == 0)
         break;
-      }
-      if (n < 0 || n > m_StackCount) {
+      if (n < 0 || n > static_cast<int>(m_StackCount))
         break;
-      }
       if (j < 0) {
         for (int i = 0; i < -j; i++) {
           FX_FLOAT first = m_Stack[m_StackCount - n];
-          for (int ii = 0; ii < n - 1; ii++) {
+          for (int ii = 0; ii < n - 1; ii++)
             m_Stack[m_StackCount - n + ii] = m_Stack[m_StackCount - n + ii + 1];
-          }
           m_Stack[m_StackCount - 1] = first;
         }
       } else {
         for (int i = 0; i < j; i++) {
           FX_FLOAT last = m_Stack[m_StackCount - 1];
           int ii;
-          for (ii = 0; ii < n - 1; ii++) {
+          for (ii = 0; ii < n - 1; ii++)
             m_Stack[m_StackCount - ii - 1] = m_Stack[m_StackCount - ii - 2];
-          }
           m_Stack[m_StackCount - ii - 1] = last;
         }
       }
@@ -549,22 +542,20 @@ FX_BOOL CPDF_SampledFunc::v_Init(CPDF_Object* pObj) {
   m_pSampleStream->LoadAllData(pStream, FALSE);
   m_pEncodeInfo = FX_Alloc(SampleEncodeInfo, m_nInputs);
   FX_SAFE_DWORD nTotalSampleBits = 1;
-  for (int i = 0; i < m_nInputs; i++) {
+  for (uint32_t i = 0; i < m_nInputs; i++) {
     m_pEncodeInfo[i].sizes = pSize ? pSize->GetIntegerAt(i) : 0;
-    if (!pSize && i == 0) {
+    if (!pSize && i == 0)
       m_pEncodeInfo[i].sizes = pDict->GetIntegerBy("Size");
-    }
     nTotalSampleBits *= m_pEncodeInfo[i].sizes;
     if (pEncode) {
       m_pEncodeInfo[i].encode_min = pEncode->GetFloatAt(i * 2);
       m_pEncodeInfo[i].encode_max = pEncode->GetFloatAt(i * 2 + 1);
     } else {
       m_pEncodeInfo[i].encode_min = 0;
-      if (m_pEncodeInfo[i].sizes == 1) {
+      if (m_pEncodeInfo[i].sizes == 1)
         m_pEncodeInfo[i].encode_max = 1;
-      } else {
+      else
         m_pEncodeInfo[i].encode_max = (FX_FLOAT)m_pEncodeInfo[i].sizes - 1;
-      }
     }
   }
   nTotalSampleBits *= m_nBitsPerSample;
@@ -577,7 +568,7 @@ FX_BOOL CPDF_SampledFunc::v_Init(CPDF_Object* pObj) {
     return FALSE;
   }
   m_pDecodeInfo = FX_Alloc(SampleDecodeInfo, m_nOutputs);
-  for (int i = 0; i < m_nOutputs; i++) {
+  for (uint32_t i = 0; i < m_nOutputs; i++) {
     if (pDecode) {
       m_pDecodeInfo[i].decode_min = pDecode->GetFloatAt(2 * i);
       m_pDecodeInfo[i].decode_max = pDecode->GetFloatAt(2 * i + 1);
@@ -595,21 +586,19 @@ FX_BOOL CPDF_SampledFunc::v_Call(FX_FLOAT* inputs, FX_FLOAT* results) const {
   CFX_FixedBufGrow<int, 32> int_buf(m_nInputs * 2);
   int* index = int_buf;
   int* blocksize = index + m_nInputs;
-  for (int i = 0; i < m_nInputs; i++) {
-    if (i == 0) {
+  for (uint32_t i = 0; i < m_nInputs; i++) {
+    if (i == 0)
       blocksize[i] = 1;
-    } else {
+    else
       blocksize[i] = blocksize[i - 1] * m_pEncodeInfo[i - 1].sizes;
-    }
     encoded_input[i] = PDF_Interpolate(
         inputs[i], m_pDomains[i * 2], m_pDomains[i * 2 + 1],
         m_pEncodeInfo[i].encode_min, m_pEncodeInfo[i].encode_max);
     index[i] = (int)encoded_input[i];
-    if (index[i] < 0) {
+    if (index[i] < 0)
       index[i] = 0;
-    } else if (index[i] > m_pEncodeInfo[i].sizes - 1) {
+    else if (index[i] > m_pEncodeInfo[i].sizes - 1)
       index[i] = m_pEncodeInfo[i].sizes - 1;
-    }
     pos += index[i] * blocksize[i];
   }
   FX_SAFE_INT32 bits_to_output = m_nOutputs;
@@ -631,25 +620,23 @@ FX_BOOL CPDF_SampledFunc::v_Call(FX_FLOAT* inputs, FX_FLOAT* results) const {
   if (!pSampleData) {
     return FALSE;
   }
-  for (int j = 0; j < m_nOutputs; j++) {
+  for (uint32_t j = 0; j < m_nOutputs; j++) {
     uint32_t sample =
         _GetBits32(pSampleData, bitpos.ValueOrDie() + j * m_nBitsPerSample,
                    m_nBitsPerSample);
     FX_FLOAT encoded = (FX_FLOAT)sample;
-    for (int i = 0; i < m_nInputs; i++) {
+    for (uint32_t i = 0; i < m_nInputs; i++) {
       if (index[i] == m_pEncodeInfo[i].sizes - 1) {
-        if (index[i] == 0) {
+        if (index[i] == 0)
           encoded = encoded_input[i] * (FX_FLOAT)sample;
-        }
       } else {
         FX_SAFE_INT32 bitpos2 = blocksize[i];
         bitpos2 += pos;
         bitpos2 *= m_nOutputs;
         bitpos2 += j;
         bitpos2 *= m_nBitsPerSample;
-        if (!bitpos2.IsValid()) {
+        if (!bitpos2.IsValid())
           return FALSE;
-        }
         uint32_t sample1 =
             _GetBits32(pSampleData, bitpos2.ValueOrDie(), m_nBitsPerSample);
         encoded += (encoded_input[i] - index[i]) *
@@ -682,17 +669,13 @@ FX_BOOL CPDF_PSFunc::v_Init(CPDF_Object* pObj) {
 FX_BOOL CPDF_PSFunc::v_Call(FX_FLOAT* inputs, FX_FLOAT* results) const {
   CPDF_PSEngine& PS = (CPDF_PSEngine&)m_PS;
   PS.Reset();
-  int i;
-  for (i = 0; i < m_nInputs; i++) {
+  for (uint32_t i = 0; i < m_nInputs; i++)
     PS.Push(inputs[i]);
-  }
   PS.Execute();
-  if (PS.GetStackSize() < m_nOutputs) {
+  if (PS.GetStackSize() < m_nOutputs)
     return FALSE;
-  }
-  for (i = 0; i < m_nOutputs; i++) {
+  for (uint32_t i = 0; i < m_nOutputs; i++)
     results[m_nOutputs - i - 1] = PS.Pop();
-  }
   return TRUE;
 }
 
@@ -723,7 +706,7 @@ FX_BOOL CPDF_ExpIntFunc::v_Init(CPDF_Object* pObj) {
   CPDF_Array* pArray1 = pDict->GetArrayBy("C1");
   m_pBeginValues = FX_Alloc2D(FX_FLOAT, m_nOutputs, 2);
   m_pEndValues = FX_Alloc2D(FX_FLOAT, m_nOutputs, 2);
-  for (int i = 0; i < m_nOutputs; i++) {
+  for (uint32_t i = 0; i < m_nOutputs; i++) {
     m_pBeginValues[i] = pArray0 ? pArray0->GetFloatAt(i) : 0.0f;
     m_pEndValues[i] = pArray1 ? pArray1->GetFloatAt(i) : 1.0f;
   }
@@ -736,8 +719,8 @@ FX_BOOL CPDF_ExpIntFunc::v_Init(CPDF_Object* pObj) {
   return TRUE;
 }
 FX_BOOL CPDF_ExpIntFunc::v_Call(FX_FLOAT* inputs, FX_FLOAT* results) const {
-  for (int i = 0; i < m_nInputs; i++)
-    for (int j = 0; j < m_nOrigOutputs; j++) {
+  for (uint32_t i = 0; i < m_nInputs; i++)
+    for (uint32_t j = 0; j < m_nOrigOutputs; j++) {
       results[i * m_nOrigOutputs + j] =
           m_pBeginValues[j] +
           (FX_FLOAT)FXSYS_pow(inputs[i], m_Exponent) *
@@ -771,24 +754,20 @@ FX_BOOL CPDF_StitchFunc::v_Init(CPDF_Object* pObj) {
     return FALSE;
   }
   uint32_t nSubs = pArray->GetCount();
-  if (nSubs == 0) {
+  if (nSubs == 0)
     return FALSE;
-  }
   m_nOutputs = 0;
   for (uint32_t i = 0; i < nSubs; i++) {
     CPDF_Object* pSub = pArray->GetDirectObjectAt(i);
-    if (pSub == pObj) {
+    if (pSub == pObj)
       return FALSE;
-    }
     std::unique_ptr<CPDF_Function> pFunc(CPDF_Function::Load(pSub));
-    if (!pFunc) {
+    if (!pFunc)
       return FALSE;
-    }
     // Check that the input dimensionality is 1, and that all output
     // dimensionalities are the same.
-    if (pFunc->CountInputs() != kRequiredNumInputs) {
+    if (pFunc->CountInputs() != kRequiredNumInputs)
       return FALSE;
-    }
     if (pFunc->CountOutputs() != m_nOutputs) {
       if (m_nOutputs)
         return FALSE;
@@ -801,30 +780,27 @@ FX_BOOL CPDF_StitchFunc::v_Init(CPDF_Object* pObj) {
   m_pBounds = FX_Alloc(FX_FLOAT, nSubs + 1);
   m_pBounds[0] = m_pDomains[0];
   pArray = pDict->GetArrayBy("Bounds");
-  if (!pArray) {
+  if (!pArray)
     return FALSE;
-  }
-  for (uint32_t i = 0; i < nSubs - 1; i++) {
+  for (uint32_t i = 0; i < nSubs - 1; i++)
     m_pBounds[i + 1] = pArray->GetFloatAt(i);
-  }
   m_pBounds[nSubs] = m_pDomains[1];
   m_pEncode = FX_Alloc2D(FX_FLOAT, nSubs, 2);
   pArray = pDict->GetArrayBy("Encode");
-  if (!pArray) {
+  if (!pArray)
     return FALSE;
-  }
-  for (uint32_t i = 0; i < nSubs * 2; i++) {
+
+  for (uint32_t i = 0; i < nSubs * 2; i++)
     m_pEncode[i] = pArray->GetFloatAt(i);
-  }
   return TRUE;
 }
 FX_BOOL CPDF_StitchFunc::v_Call(FX_FLOAT* inputs, FX_FLOAT* outputs) const {
   FX_FLOAT input = inputs[0];
   size_t i;
-  for (i = 0; i < m_pSubFunctions.size() - 1; i++)
-    if (input < m_pBounds[i + 1]) {
+  for (i = 0; i < m_pSubFunctions.size() - 1; i++) {
+    if (input < m_pBounds[i + 1])
       break;
-    }
+  }
   if (!m_pSubFunctions[i]) {
     return FALSE;
   }
@@ -888,7 +864,7 @@ FX_BOOL CPDF_Function::Init(CPDF_Object* pObj) {
     return FALSE;
 
   m_pDomains = FX_Alloc2D(FX_FLOAT, m_nInputs, 2);
-  for (int i = 0; i < m_nInputs * 2; i++) {
+  for (uint32_t i = 0; i < m_nInputs * 2; i++) {
     m_pDomains[i] = pDomains->GetFloatAt(i);
   }
   CPDF_Array* pRanges = pDict->GetArrayBy("Range");
@@ -896,15 +872,13 @@ FX_BOOL CPDF_Function::Init(CPDF_Object* pObj) {
   if (pRanges) {
     m_nOutputs = pRanges->GetCount() / 2;
     m_pRanges = FX_Alloc2D(FX_FLOAT, m_nOutputs, 2);
-    for (int i = 0; i < m_nOutputs * 2; i++) {
+    for (uint32_t i = 0; i < m_nOutputs * 2; i++)
       m_pRanges[i] = pRanges->GetFloatAt(i);
-    }
   }
   uint32_t old_outputs = m_nOutputs;
-  if (!v_Init(pObj)) {
+  if (!v_Init(pObj))
     return FALSE;
-  }
-  if (m_pRanges && m_nOutputs > (int)old_outputs) {
+  if (m_pRanges && m_nOutputs > old_outputs) {
     m_pRanges = FX_Realloc(FX_FLOAT, m_pRanges, m_nOutputs * 2);
     if (m_pRanges) {
       FXSYS_memset(m_pRanges + (old_outputs * 2), 0,
@@ -914,28 +888,26 @@ FX_BOOL CPDF_Function::Init(CPDF_Object* pObj) {
   return TRUE;
 }
 FX_BOOL CPDF_Function::Call(FX_FLOAT* inputs,
-                            int ninputs,
+                            uint32_t ninputs,
                             FX_FLOAT* results,
                             int& nresults) const {
   if (m_nInputs != ninputs) {
     return FALSE;
   }
   nresults = m_nOutputs;
-  for (int i = 0; i < m_nInputs; i++) {
-    if (inputs[i] < m_pDomains[i * 2]) {
+  for (uint32_t i = 0; i < m_nInputs; i++) {
+    if (inputs[i] < m_pDomains[i * 2])
       inputs[i] = m_pDomains[i * 2];
-    } else if (inputs[i] > m_pDomains[i * 2 + 1]) {
+    else if (inputs[i] > m_pDomains[i * 2 + 1])
       inputs[i] = m_pDomains[i * 2] + 1;
-    }
   }
   v_Call(inputs, results);
   if (m_pRanges) {
-    for (int i = 0; i < m_nOutputs; i++) {
-      if (results[i] < m_pRanges[i * 2]) {
+    for (uint32_t i = 0; i < m_nOutputs; i++) {
+      if (results[i] < m_pRanges[i * 2])
         results[i] = m_pRanges[i * 2];
-      } else if (results[i] > m_pRanges[i * 2 + 1]) {
+      else if (results[i] > m_pRanges[i * 2 + 1])
         results[i] = m_pRanges[i * 2 + 1];
-      }
     }
   }
   return TRUE;
diff --git a/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index 32517d6b54..bf691f41d2 100644
--- a/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -1126,15 +1126,14 @@ void CPDF_StreamContentParser::Handle_SetColorPS_Fill() {
   if (!pLastParam) {
     return;
   }
-  int nargs = m_ParamCount;
-  int nvalues = nargs;
-  if (pLastParam->IsName()) {
+  uint32_t nargs = m_ParamCount;
+  uint32_t nvalues = nargs;
+  if (pLastParam->IsName())
     nvalues--;
-  }
   FX_FLOAT* values = NULL;
   if (nvalues) {
     values = FX_Alloc(FX_FLOAT, nvalues);
-    for (int i = 0; i < nvalues; i++) {
+    for (uint32_t i = 0; i < nvalues; i++) {
       values[i] = GetNumber(nargs - i - 1);
     }
   }
diff --git a/core/fpdfapi/fpdf_page/fpdf_page_parser_old_unittest.cpp b/core/fpdfapi/fpdf_page/fpdf_page_parser_old_unittest.cpp
index f4c33d2811..ff15b21d73 100644
--- a/core/fpdfapi/fpdf_page/fpdf_page_parser_old_unittest.cpp
+++ b/core/fpdfapi/fpdf_page/fpdf_page_parser_old_unittest.cpp
@@ -19,7 +19,7 @@ TEST(fpdf_page_parser_old, ReadHexString) {
     uint8_t data[] = "1A2b>abcd";
     CPDF_StreamParser parser(data, 5);
     EXPECT_EQ("\x1a\x2b", parser.ReadHexString());
-    EXPECT_EQ(5, parser.GetPos());
+    EXPECT_EQ(5u, parser.GetPos());
   }
 
   {
@@ -27,7 +27,7 @@ TEST(fpdf_page_parser_old, ReadHexString) {
     uint8_t data[] = "1A2b";
     CPDF_StreamParser parser(data, 5);
     EXPECT_EQ("\x1a\x2b", parser.ReadHexString());
-    EXPECT_EQ(5, parser.GetPos());
+    EXPECT_EQ(5u, parser.GetPos());
   }
 
   {
@@ -35,13 +35,13 @@ TEST(fpdf_page_parser_old, ReadHexString) {
     uint8_t data[] = "1A2>asdf";
     CPDF_StreamParser parser(data, 5);
     EXPECT_EQ("\x1a\x20", parser.ReadHexString());
-    EXPECT_EQ(4, parser.GetPos());
+    EXPECT_EQ(4u, parser.GetPos());
   }
 
   {
     uint8_t data[] = ">";
     CPDF_StreamParser parser(data, 5);
     EXPECT_EQ("", parser.ReadHexString());
-    EXPECT_EQ(1, parser.GetPos());
+    EXPECT_EQ(1u, parser.GetPos());
   }
 }
diff --git a/core/fpdfapi/fpdf_page/pageint.h b/core/fpdfapi/fpdf_page/pageint.h
index d76eea49d2..4fa62c03cb 100644
--- a/core/fpdfapi/fpdf_page/pageint.h
+++ b/core/fpdfapi/fpdf_page/pageint.h
@@ -387,11 +387,11 @@ class CPDF_Function {
   static CPDF_Function* Load(CPDF_Object* pFuncObj);
   virtual ~CPDF_Function();
   FX_BOOL Call(FX_FLOAT* inputs,
-               int ninputs,
+               uint32_t ninputs,
                FX_FLOAT* results,
                int& nresults) const;
-  int CountInputs() const { return m_nInputs; }
-  int CountOutputs() const { return m_nOutputs; }
+  uint32_t CountInputs() const { return m_nInputs; }
+  uint32_t CountOutputs() const { return m_nOutputs; }
   FX_FLOAT GetDomain(int i) const { return m_pDomains[i]; }
   Type GetType() const { return m_Type; }
 
@@ -401,8 +401,8 @@ class CPDF_Function {
   virtual FX_BOOL v_Init(CPDF_Object* pObj) = 0;
   virtual FX_BOOL v_Call(FX_FLOAT* inputs, FX_FLOAT* results) const = 0;
 
-  int m_nInputs;
-  int m_nOutputs;
+  uint32_t m_nInputs;
+  uint32_t m_nOutputs;
   FX_FLOAT* m_pDomains;
   FX_FLOAT* m_pRanges;
   Type m_Type;
@@ -417,7 +417,7 @@ class CPDF_ExpIntFunc : public CPDF_Function {
   FX_BOOL v_Init(CPDF_Object* pObj) override;
   FX_BOOL v_Call(FX_FLOAT* inputs, FX_FLOAT* results) const override;
 
-  int m_nOrigOutputs;
+  uint32_t m_nOrigOutputs;
   FX_FLOAT m_Exponent;
   FX_FLOAT* m_pBeginValues;
   FX_FLOAT* m_pEndValues;
@@ -436,7 +436,7 @@ class CPDF_StitchFunc : public CPDF_Function {
   FX_FLOAT* m_pBounds;
   FX_FLOAT* m_pEncode;
 
-  static const int kRequiredNumInputs = 1;
+  static const uint32_t kRequiredNumInputs = 1;
 };
 
 class CPDF_IccProfile {
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,
diff --git a/core/fpdfapi/fpdf_render/fpdf_render_pattern.cpp b/core/fpdfapi/fpdf_render/fpdf_render_pattern.cpp
index 9c1fa36b28..d3081da26f 100644
--- a/core/fpdfapi/fpdf_render/fpdf_render_pattern.cpp
+++ b/core/fpdfapi/fpdf_render/fpdf_render_pattern.cpp
@@ -58,15 +58,13 @@ static void DrawAxialShading(CFX_DIBitmap* pBitmap,
   FX_FLOAT axis_len_square = (x_span * x_span) + (y_span * y_span);
   CFX_Matrix matrix;
   matrix.SetReverse(*pObject2Bitmap);
-  int total_results = 0;
+  uint32_t total_results = 0;
   for (int j = 0; j < nFuncs; j++) {
-    if (pFuncs[j]) {
+    if (pFuncs[j])
       total_results += pFuncs[j]->CountOutputs();
-    }
   }
-  if (pCS->CountComponents() > total_results) {
+  if (pCS->CountComponents() > total_results)
     total_results = pCS->CountComponents();
-  }
   CFX_FixedBufGrow<FX_FLOAT, 16> result_array(total_results);
   FX_FLOAT* pResults = result_array;
   FXSYS_memset(pResults, 0, total_results * sizeof(FX_FLOAT));
@@ -144,7 +142,7 @@ static void DrawRadialShading(CFX_DIBitmap* pBitmap,
     bStartExtend = pArray->GetIntegerAt(0);
     bEndExtend = pArray->GetIntegerAt(1);
   }
-  int total_results = 0;
+  uint32_t total_results = 0;
   for (int j = 0; j < nFuncs; j++) {
     if (pFuncs[j]) {
       total_results += pFuncs[j]->CountOutputs();
@@ -273,15 +271,13 @@ static void DrawFuncShading(CFX_DIBitmap* pBitmap,
   int width = pBitmap->GetWidth();
   int height = pBitmap->GetHeight();
   int pitch = pBitmap->GetPitch();
-  int total_results = 0;
+  uint32_t total_results = 0;
   for (int j = 0; j < nFuncs; j++) {
-    if (pFuncs[j]) {
+    if (pFuncs[j])
       total_results += pFuncs[j]->CountOutputs();
-    }
   }
-  if (pCS->CountComponents() > total_results) {
+  if (pCS->CountComponents() > total_results)
     total_results = pCS->CountComponents();
-  }
   CFX_FixedBufGrow<FX_FLOAT, 16> result_array(total_results);
   FX_FLOAT* pResults = result_array;
   FXSYS_memset(pResults, 0, total_results * sizeof(FX_FLOAT));
@@ -845,9 +841,8 @@ void CPDF_RenderStatus::DrawShading(CPDF_ShadingPattern* pPattern,
     if (pBackColor &&
         pBackColor->GetCount() >= pColorSpace->CountComponents()) {
       CFX_FixedBufGrow<FX_FLOAT, 16> comps(pColorSpace->CountComponents());
-      for (int i = 0; i < pColorSpace->CountComponents(); i++) {
+      for (uint32_t i = 0; i < pColorSpace->CountComponents(); i++)
         comps[i] = pBackColor->GetNumberAt(i);
-      }
       FX_FLOAT R = 0.0f, G = 0.0f, B = 0.0f;
       pColorSpace->GetRGB(comps, R, G, B);
       background = ArgbEncode(255, (int32_t)(R * 255), (int32_t)(G * 255),
diff --git a/core/fpdfdoc/doc_formfield.cpp b/core/fpdfdoc/doc_formfield.cpp
index cc34a9d297..4ebf2d3020 100644
--- a/core/fpdfdoc/doc_formfield.cpp
+++ b/core/fpdfdoc/doc_formfield.cpp
@@ -458,11 +458,9 @@ int CPDF_FormField::GetSelectedIndex(int index) {
       return iOptIndex;
     }
   }
-  int nOpts = CountOptions();
-  for (int i = 0; i < nOpts; i++) {
-    if (sel_value == GetOptionValue(i)) {
+  for (int i = 0; i < CountOptions(); i++) {
+    if (sel_value == GetOptionValue(i))
       return i;
-    }
   }
   return -1;
 }
@@ -500,6 +498,7 @@ FX_BOOL CPDF_FormField::ClearSelection(FX_BOOL bNotify) {
   m_pForm->m_bUpdated = TRUE;
   return TRUE;
 }
+
 FX_BOOL CPDF_FormField::IsItemSelected(int index) {
   ASSERT(GetType() == ComboBox || GetType() == ListBox);
   if (index < 0 || index >= CountOptions()) {
@@ -544,6 +543,7 @@ FX_BOOL CPDF_FormField::IsItemSelected(int index) {
     }
   return FALSE;
 }
+
 FX_BOOL CPDF_FormField::SetItemSelection(int index,
                                          FX_BOOL bSelected,
                                          FX_BOOL bNotify) {
@@ -575,20 +575,16 @@ FX_BOOL CPDF_FormField::SetItemSelection(int index,
           }
         } else if (pValue->IsArray()) {
           CPDF_Array* pArray = new CPDF_Array;
-          int iCount = CountOptions();
-          for (int i = 0; i < iCount; i++) {
-            if (i != index) {
-              if (IsItemSelected(i)) {
-                opt_value = GetOptionValue(i);
-                pArray->AddString(PDF_EncodeText(opt_value));
-              }
+          for (int i = 0; i < CountOptions(); i++) {
+            if (i != index && IsItemSelected(i)) {
+              opt_value = GetOptionValue(i);
+              pArray->AddString(PDF_EncodeText(opt_value));
             }
           }
-          if (pArray->GetCount() < 1) {
+          if (pArray->GetCount() < 1)
             pArray->Release();
-          } else {
+          else
             m_pDict->SetAt("V", pArray);
-          }
         }
       } else if (m_Type == ComboBox) {
         m_pDict->RemoveAt("V");
@@ -602,15 +598,8 @@ FX_BOOL CPDF_FormField::SetItemSelection(int index,
         m_pDict->SetAtString("V", PDF_EncodeText(opt_value));
       } else {
         CPDF_Array* pArray = new CPDF_Array;
-        int iCount = CountOptions();
-        for (int i = 0; i < iCount; i++) {
-          FX_BOOL bSelected;
-          if (i != index) {
-            bSelected = IsItemSelected(i);
-          } else {
-            bSelected = TRUE;
-          }
-          if (bSelected) {
+        for (int i = 0; i < CountOptions(); i++) {
+          if (i == index || IsItemSelected(i)) {
             opt_value = GetOptionValue(i);
             pArray->AddString(PDF_EncodeText(opt_value));
           }
@@ -638,54 +627,46 @@ FX_BOOL CPDF_FormField::SetItemSelection(int index,
   m_pForm->m_bUpdated = TRUE;
   return TRUE;
 }
+
 FX_BOOL CPDF_FormField::IsItemDefaultSelected(int index) {
   ASSERT(GetType() == ComboBox || GetType() == ListBox);
-  if (index < 0 || index >= CountOptions()) {
+  if (index < 0 || index >= CountOptions())
     return FALSE;
-  }
   int iDVIndex = GetDefaultSelectedItem();
-  if (iDVIndex < 0) {
-    return FALSE;
-  }
-  return (iDVIndex == index);
+  return iDVIndex >= 0 && iDVIndex == index;
 }
+
 int CPDF_FormField::GetDefaultSelectedItem() {
   ASSERT(GetType() == ComboBox || GetType() == ListBox);
   CPDF_Object* pValue = FPDF_GetFieldAttr(m_pDict, "DV");
-  if (!pValue) {
+  if (!pValue)
     return -1;
-  }
   CFX_WideString csDV = pValue->GetUnicodeText();
-  if (csDV.IsEmpty()) {
+  if (csDV.IsEmpty())
     return -1;
-  }
-  int iCount = CountOptions();
-  for (int i = 0; i < iCount; i++) {
-    if (csDV == GetOptionValue(i)) {
+  for (int i = 0; i < CountOptions(); i++) {
+    if (csDV == GetOptionValue(i))
       return i;
-    }
   }
   return -1;
 }
+
 void CPDF_FormField::UpdateAP(CPDF_FormControl* pControl) {
-  if (m_Type == PushButton) {
-    return;
-  }
-  if (m_Type == RadioButton || m_Type == CheckBox) {
+  if (m_Type == PushButton || m_Type == RadioButton || m_Type == CheckBox)
     return;
-  }
-  if (!m_pForm->m_bGenerateAP) {
+  if (!m_pForm->m_bGenerateAP)
     return;
-  }
   for (int i = 0; i < CountControls(); i++) {
     CPDF_FormControl* pControl = GetControl(i);
     FPDF_GenerateAP(m_pForm->m_pDocument, pControl->m_pWidgetDict);
   }
 }
+
 int CPDF_FormField::CountOptions() {
   CPDF_Array* pArray = ToArray(FPDF_GetFieldAttr(m_pDict, "Opt"));
   return pArray ? pArray->GetCount() : 0;
 }
+
 CFX_WideString CPDF_FormField::GetOptionText(int index, int sub_index) {
   CPDF_Array* pArray = ToArray(FPDF_GetFieldAttr(m_pDict, "Opt"));
   if (!pArray)
@@ -706,30 +687,23 @@ CFX_WideString CPDF_FormField::GetOptionLabel(int index) {
 CFX_WideString CPDF_FormField::GetOptionValue(int index) {
   return GetOptionText(index, 0);
 }
+
 int CPDF_FormField::FindOption(CFX_WideString csOptLabel) {
-  int iCount = CountOptions();
-  for (int i = 0; i < iCount; i++) {
-    CFX_WideString csValue = GetOptionValue(i);
-    if (csValue == csOptLabel) {
+  for (int i = 0; i < CountOptions(); i++) {
+    if (GetOptionValue(i) == csOptLabel)
       return i;
-    }
   }
   return -1;
 }
-int CPDF_FormField::FindOptionValue(const CFX_WideString& csOptValue,
-                                    int iStartIndex) {
-  if (iStartIndex < 0) {
-    iStartIndex = 0;
-  }
-  int iCount = CountOptions();
-  for (; iStartIndex < iCount; iStartIndex++) {
-    CFX_WideString csValue = GetOptionValue(iStartIndex);
-    if (csValue == csOptValue) {
-      return iStartIndex;
-    }
+
+int CPDF_FormField::FindOptionValue(const CFX_WideString& csOptValue) {
+  for (int i = 0; i < CountOptions(); i++) {
+    if (GetOptionValue(i) == csOptValue)
+      return i;
   }
   return -1;
 }
+
 #ifdef PDF_ENABLE_XFA
 int CPDF_FormField::InsertOption(CFX_WideString csOptLabel,
                                  int index,
diff --git a/core/fpdftext/fpdf_text_int_unittest.cpp b/core/fpdftext/fpdf_text_int_unittest.cpp
index 1510ebc06c..e62e885d4b 100644
--- a/core/fpdftext/fpdf_text_int_unittest.cpp
+++ b/core/fpdftext/fpdf_text_int_unittest.cpp
@@ -26,7 +26,7 @@ TEST(fpdf_text_int, CheckMailLink) {
       L"abc@.xyz.org",    // Domain name should not start with '.'.
       L"fan@g..com"       // Domain name should not have consecutive '.'
   };
-  for (int i = 0; i < FX_ArraySize(invalid_strs); ++i) {
+  for (size_t i = 0; i < FX_ArraySize(invalid_strs); ++i) {
     CFX_WideString text_str(invalid_strs[i]);
     EXPECT_FALSE(extractor.CheckMailLink(text_str));
   }
@@ -46,7 +46,7 @@ TEST(fpdf_text_int, CheckMailLink) {
       {L"fan@g.com..", L"fan@g.com"},           // Trim the ending periods.
       {L"CAP.cap@Gmail.Com", L"CAP.cap@Gmail.Com"},  // Keep the original case.
   };
-  for (int i = 0; i < FX_ArraySize(valid_strs); ++i) {
+  for (size_t i = 0; i < FX_ArraySize(valid_strs); ++i) {
     CFX_WideString text_str(valid_strs[i][0]);
     CFX_WideString expected_str(L"mailto:");
     expected_str += valid_strs[i][1];
diff --git a/core/fxcodec/codec/fx_codec_jpx_unittest.cpp b/core/fxcodec/codec/fx_codec_jpx_unittest.cpp
index 765d8a2e59..13b5425927 100644
--- a/core/fxcodec/codec/fx_codec_jpx_unittest.cpp
+++ b/core/fxcodec/codec/fx_codec_jpx_unittest.cpp
@@ -296,7 +296,7 @@ TEST(fxcodec, DecodeDataSkip) {
 
     // Skiping within buffer is allowed.
     memset(buffer, 0xbd, sizeof(buffer));
-    EXPECT_EQ(1, opj_skip_from_memory(1, &dd));
+    EXPECT_EQ(1u, opj_skip_from_memory(1, &dd));
     EXPECT_EQ(1u, opj_read_from_memory(buffer, 1, &dd));
     EXPECT_EQ(0x01, buffer[0]);
     EXPECT_EQ(0xbd, buffer[1]);
@@ -310,7 +310,7 @@ TEST(fxcodec, DecodeDataSkip) {
 
     // Skiping to EOS-1 is possible.
     memset(buffer, 0xbd, sizeof(buffer));
-    EXPECT_EQ(4, opj_skip_from_memory(4, &dd));
+    EXPECT_EQ(4u, opj_skip_from_memory(4, &dd));
     EXPECT_EQ(1u, opj_read_from_memory(buffer, 1, &dd));
     EXPECT_EQ(0x87, buffer[0]);
     EXPECT_EQ(0xbd, buffer[1]);
@@ -325,7 +325,7 @@ TEST(fxcodec, DecodeDataSkip) {
 
     // Skiping directly to EOS is allowed.
     memset(buffer, 0xbd, sizeof(buffer));
-    EXPECT_EQ(8, opj_skip_from_memory(8, &dd));
+    EXPECT_EQ(8u, opj_skip_from_memory(8, &dd));
 
     // Next read fails.
     EXPECT_EQ(kReadError, opj_read_from_memory(buffer, 1, &dd));
@@ -336,7 +336,7 @@ TEST(fxcodec, DecodeDataSkip) {
 
     // Skipping beyond end of stream is allowed and returns full distance.
     memset(buffer, 0xbd, sizeof(buffer));
-    EXPECT_EQ(9, opj_skip_from_memory(9, &dd));
+    EXPECT_EQ(9u, opj_skip_from_memory(9, &dd));
 
     // Next read fails.
     EXPECT_EQ(kReadError, opj_read_from_memory(buffer, 1, &dd));
@@ -348,7 +348,7 @@ TEST(fxcodec, DecodeDataSkip) {
     // Skipping way beyond EOS is allowd, doesn't wrap, and returns
     // full distance.
     memset(buffer, 0xbd, sizeof(buffer));
-    EXPECT_EQ(4, opj_skip_from_memory(4, &dd));
+    EXPECT_EQ(4u, opj_skip_from_memory(4, &dd));
     EXPECT_EQ(std::numeric_limits<OPJ_OFF_T>::max(),
               opj_skip_from_memory(std::numeric_limits<OPJ_OFF_T>::max(), &dd));
 
@@ -361,7 +361,7 @@ TEST(fxcodec, DecodeDataSkip) {
 
     // Negative skip within buffer not is allowed, position unchanged.
     memset(buffer, 0xbd, sizeof(buffer));
-    EXPECT_EQ(4, opj_skip_from_memory(4, &dd));
+    EXPECT_EQ(4u, opj_skip_from_memory(4, &dd));
     EXPECT_EQ(kSkipError, opj_skip_from_memory(-2, &dd));
 
     // Next read succeeds as if nothing has happenned.
@@ -383,12 +383,12 @@ TEST(fxcodec, DecodeDataSkip) {
 
     // Negative skip way before buffer is not allowed, doesn't wrap
     memset(buffer, 0xbd, sizeof(buffer));
-    EXPECT_EQ(4, opj_skip_from_memory(4, &dd));
+    EXPECT_EQ(4u, opj_skip_from_memory(4, &dd));
     EXPECT_EQ(kSkipError,
               opj_skip_from_memory(std::numeric_limits<OPJ_OFF_T>::min(), &dd));
 
     // Next read succeeds. If it fails, it may mean we wrapped.
-    EXPECT_EQ(1, opj_read_from_memory(buffer, 1, &dd));
+    EXPECT_EQ(1u, opj_read_from_memory(buffer, 1, &dd));
     EXPECT_EQ(0x84, buffer[0]);
     EXPECT_EQ(0xbd, buffer[1]);
   }
@@ -397,7 +397,7 @@ TEST(fxcodec, DecodeDataSkip) {
 
     // Negative skip after EOS isn't alowed, still EOS.
     memset(buffer, 0xbd, sizeof(buffer));
-    EXPECT_EQ(8, opj_skip_from_memory(8, &dd));
+    EXPECT_EQ(8u, opj_skip_from_memory(8, &dd));
     EXPECT_EQ(kSkipError, opj_skip_from_memory(-4, &dd));
 
     // Next read fails.
@@ -420,7 +420,7 @@ TEST(fxcodec, DecodeDataSeek) {
   // Seeking before start returns error leaving position unchanged.
   memset(buffer, 0xbd, sizeof(buffer));
   EXPECT_FALSE(opj_seek_from_memory(-1, &dd));
-  EXPECT_EQ(1, opj_read_from_memory(buffer, 1, &dd));
+  EXPECT_EQ(1u, opj_read_from_memory(buffer, 1, &dd));
   EXPECT_EQ(0x02, buffer[0]);
   EXPECT_EQ(0xbd, buffer[1]);
 
@@ -428,7 +428,7 @@ TEST(fxcodec, DecodeDataSeek) {
   memset(buffer, 0xbd, sizeof(buffer));
   EXPECT_FALSE(
       opj_seek_from_memory(std::numeric_limits<OPJ_OFF_T>::min(), &dd));
-  EXPECT_EQ(1, opj_read_from_memory(buffer, 1, &dd));
+  EXPECT_EQ(1u, opj_read_from_memory(buffer, 1, &dd));
   EXPECT_EQ(0x03, buffer[0]);
   EXPECT_EQ(0xbd, buffer[1]);
 
@@ -498,7 +498,7 @@ TEST(fxcodec, YUV420ToRGB) {
     bool expected;
   } cases[] = {{0, false}, {1, false},  {30, false}, {31, true},
                {32, true}, {33, false}, {34, false}, {UINT_MAX, false}};
-  for (int i = 0; i < sizeof(cases) / sizeof(cases[0]); ++i) {
+  for (size_t i = 0; i < sizeof(cases) / sizeof(cases[0]); ++i) {
     y.w = cases[i].w;
     y.h = y.w;
     img.x1 = y.w;
diff --git a/core/fxcrt/fx_basic_gcc_unittest.cpp b/core/fxcrt/fx_basic_gcc_unittest.cpp
index 8d8d2f5deb..c6913cfd82 100644
--- a/core/fxcrt/fx_basic_gcc_unittest.cpp
+++ b/core/fxcrt/fx_basic_gcc_unittest.cpp
@@ -93,16 +93,16 @@ TEST(fxcrt, FXSYS_wtoi64) {
 }
 
 TEST(fxcrt, FXSYS_atoui) {
-  EXPECT_EQ(0, FXSYS_atoui(""));
-  EXPECT_EQ(0, FXSYS_atoui("0"));
+  EXPECT_EQ(0u, FXSYS_atoui(""));
+  EXPECT_EQ(0u, FXSYS_atoui("0"));
   EXPECT_EQ(4294967295, FXSYS_atoui("-1"));
-  EXPECT_EQ(2345, FXSYS_atoui("2345"));
+  EXPECT_EQ(2345u, FXSYS_atoui("2345"));
   // Handle the sign.
   EXPECT_EQ(4294964951, FXSYS_atoui("-2345"));
-  EXPECT_EQ(2345, FXSYS_atoui("+2345"));
+  EXPECT_EQ(2345u, FXSYS_atoui("+2345"));
   // The max value.
   EXPECT_EQ(4294967295, FXSYS_atoui("4294967295"));
-  EXPECT_EQ(9, FXSYS_atoui("9x9"));
+  EXPECT_EQ(9u, FXSYS_atoui("9x9"));
 
   // Out of range values.
   EXPECT_EQ(4294967295, FXSYS_atoui("2147483623423412348"));
diff --git a/core/fxcrt/include/fx_string.h b/core/fxcrt/include/fx_string.h
index e5f9466b21..0aa34171c2 100644
--- a/core/fxcrt/include/fx_string.h
+++ b/core/fxcrt/include/fx_string.h
@@ -134,7 +134,9 @@ inline bool operator==(const char* lhs, const CFX_ByteStringC& rhs) {
 inline bool operator!=(const char* lhs, const CFX_ByteStringC& rhs) {
   return rhs != lhs;
 }
-#define FXBSTR_ID(c1, c2, c3, c4) ((c1 << 24) | (c2 << 16) | (c3 << 8) | (c4))
+#define FXBSTR_ID(c1, c2, c3, c4)                                      \
+  (((uint32_t)c1 << 24) | ((uint32_t)c2 << 16) | ((uint32_t)c3 << 8) | \
+   ((uint32_t)c4))
 
 // A mutable string with shared buffers using copy-on-write semantics that
 // avoids the cost of std::string's iterator stability guarantees.
diff --git a/core/fxge/ge/fx_ge_text.cpp b/core/fxge/ge/fx_ge_text.cpp
index 10c769aa6b..1d18ecd377 100644
--- a/core/fxge/ge/fx_ge_text.cpp
+++ b/core/fxge/ge/fx_ge_text.cpp
@@ -1536,12 +1536,14 @@ CFX_GlyphBitmap* CFX_FaceCache::RenderGlyph(CFX_Font* pFont,
       skew = pSubstFont->m_ItalicAngle;
     }
     if (skew) {
-      skew = skew <= -ANGLESKEW_ARRAY_SIZE ? -58 : -g_AngleSkew[-skew];
-      if (pFont->IsVertical()) {
+      // skew is nonpositive so -skew is used as the index.
+      skew = -skew <= static_cast<int>(ANGLESKEW_ARRAY_SIZE)
+                 ? -58
+                 : -g_AngleSkew[-skew];
+      if (pFont->IsVertical())
         ft_matrix.yx += ft_matrix.yy * skew / 100;
-      } else {
+      else
         ft_matrix.xy += -ft_matrix.xx * skew / 100;
-      }
     }
     if (pSubstFont->m_SubstFlags & FXFONT_SUBST_MM) {
       pFont->AdjustMMParams(glyph_index, dest_width,
@@ -1574,10 +1576,9 @@ CFX_GlyphBitmap* CFX_FaceCache::RenderGlyph(CFX_Font* pFont,
   }
   if (pSubstFont && !(pSubstFont->m_SubstFlags & FXFONT_SUBST_MM) &&
       weight > 400) {
-    int index = (weight - 400) / 10;
-    if (index >= WEIGHTPOW_ARRAY_SIZE) {
+    uint32_t index = (weight - 400) / 10;
+    if (index >= WEIGHTPOW_ARRAY_SIZE)
       return NULL;
-    }
     int level = 0;
     if (pSubstFont->m_Charset == FXFONT_SHIFTJIS_CHARSET) {
       level =
@@ -1801,12 +1802,14 @@ CFX_PathData* CFX_Font::LoadGlyphPath(uint32_t glyph_index, int dest_width) {
   if (m_pSubstFont) {
     if (m_pSubstFont->m_ItalicAngle) {
       int skew = m_pSubstFont->m_ItalicAngle;
-      skew = skew <= -ANGLESKEW_ARRAY_SIZE ? -58 : -g_AngleSkew[-skew];
-      if (m_bVertical) {
+      // skew is nonpositive so -skew is used as the index.
+      skew = -skew <= static_cast<int>(ANGLESKEW_ARRAY_SIZE)
+                 ? -58
+                 : -g_AngleSkew[-skew];
+      if (m_bVertical)
         ft_matrix.yx += ft_matrix.yy * skew / 100;
-      } else {
+      else
         ft_matrix.xy += -ft_matrix.xx * skew / 100;
-      }
     }
     if (m_pSubstFont->m_SubstFlags & FXFONT_SUBST_MM) {
       AdjustMMParams(glyph_index, dest_width, m_pSubstFont->m_Weight);
@@ -1817,21 +1820,18 @@ CFX_PathData* CFX_Font::LoadGlyphPath(uint32_t glyph_index, int dest_width) {
   if (!(m_Face->face_flags & FT_FACE_FLAG_SFNT) || !FT_IS_TRICKY(m_Face)) {
     load_flags |= FT_LOAD_NO_HINTING;
   }
-  int error = FXFT_Load_Glyph(m_Face, glyph_index, load_flags);
-  if (error) {
+  if (FXFT_Load_Glyph(m_Face, glyph_index, load_flags))
     return NULL;
-  }
   if (m_pSubstFont && !(m_pSubstFont->m_SubstFlags & FXFONT_SUBST_MM) &&
       m_pSubstFont->m_Weight > 400) {
-    int index = (m_pSubstFont->m_Weight - 400) / 10;
+    uint32_t index = (m_pSubstFont->m_Weight - 400) / 10;
     if (index >= WEIGHTPOW_ARRAY_SIZE)
       index = WEIGHTPOW_ARRAY_SIZE - 1;
     int level = 0;
-    if (m_pSubstFont->m_Charset == FXFONT_SHIFTJIS_CHARSET) {
+    if (m_pSubstFont->m_Charset == FXFONT_SHIFTJIS_CHARSET)
       level = g_WeightPow_SHIFTJIS[index] * 2 * 65536 / 36655;
-    } else {
+    else
       level = g_WeightPow[index] * 2;
-    }
     FXFT_Outline_Embolden(FXFT_Get_Glyph_Outline(m_Face), level);
   }
   FXFT_Outline_Funcs funcs;
diff --git a/core/include/fpdfdoc/fpdf_doc.h b/core/include/fpdfdoc/fpdf_doc.h
index 87d1662c81..5939966995 100644
--- a/core/include/fpdfdoc/fpdf_doc.h
+++ b/core/include/fpdfdoc/fpdf_doc.h
@@ -722,7 +722,7 @@ class CPDF_FormField {
 
   int FindOption(CFX_WideString csOptLabel);
 
-  int FindOptionValue(const CFX_WideString& csOptValue, int iStartIndex = 0);
+  int FindOptionValue(const CFX_WideString& csOptValue);
 
   FX_BOOL CheckControl(int iControlIndex,
                        bool bChecked,
diff --git a/fpdfsdk/fpdfdoc_embeddertest.cpp b/fpdfsdk/fpdfdoc_embeddertest.cpp
index bf91038ca6..855235858b 100644
--- a/fpdfsdk/fpdfdoc_embeddertest.cpp
+++ b/fpdfsdk/fpdfdoc_embeddertest.cpp
@@ -72,7 +72,7 @@ TEST_F(FPDFDocEmbeddertest, NoBookmarks) {
 
   // The non-existent top-level bookmark has no title.
   unsigned short buf[128];
-  EXPECT_EQ(0, FPDFBookmark_GetTitle(nullptr, buf, sizeof(buf)));
+  EXPECT_EQ(0u, FPDFBookmark_GetTitle(nullptr, buf, sizeof(buf)));
 
   // The non-existent top-level bookmark has no children.
   EXPECT_EQ(nullptr, FPDFBookmark_GetFirstChild(document(), nullptr));
@@ -84,11 +84,11 @@ TEST_F(FPDFDocEmbeddertest, Bookmarks) {
 
   // The existent top-level bookmark has no title.
   unsigned short buf[128];
-  EXPECT_EQ(0, FPDFBookmark_GetTitle(nullptr, buf, sizeof(buf)));
+  EXPECT_EQ(0u, FPDFBookmark_GetTitle(nullptr, buf, sizeof(buf)));
 
   FPDF_BOOKMARK child = FPDFBookmark_GetFirstChild(document(), nullptr);
   EXPECT_NE(nullptr, child);
-  EXPECT_EQ(34, FPDFBookmark_GetTitle(child, buf, sizeof(buf)));
+  EXPECT_EQ(34u, FPDFBookmark_GetTitle(child, buf, sizeof(buf)));
   EXPECT_EQ(CFX_WideString(L"A Good Beginning"),
             CFX_WideString::FromUTF16LE(buf, 16));
 
@@ -96,7 +96,7 @@ TEST_F(FPDFDocEmbeddertest, Bookmarks) {
 
   FPDF_BOOKMARK sibling = FPDFBookmark_GetNextSibling(document(), child);
   EXPECT_NE(nullptr, sibling);
-  EXPECT_EQ(28, FPDFBookmark_GetTitle(sibling, buf, sizeof(buf)));
+  EXPECT_EQ(28u, FPDFBookmark_GetTitle(sibling, buf, sizeof(buf)));
   EXPECT_EQ(CFX_WideString(L"A Good Ending"),
             CFX_WideString::FromUTF16LE(buf, 13));
 
@@ -115,7 +115,7 @@ TEST_F(FPDFDocEmbeddertest, FindBookmarks) {
 
   // Check that the string matches.
   unsigned short buf[128];
-  EXPECT_EQ(34, FPDFBookmark_GetTitle(child, buf, sizeof(buf)));
+  EXPECT_EQ(34u, FPDFBookmark_GetTitle(child, buf, sizeof(buf)));
   EXPECT_EQ(CFX_WideString(L"A Good Beginning"),
             CFX_WideString::FromUTF16LE(buf, 16));
 
diff --git a/fpdfsdk/fpdfsave_embeddertest.cpp b/fpdfsdk/fpdfsave_embeddertest.cpp
index 2b138a61e4..5dbff36327 100644
--- a/fpdfsdk/fpdfsave_embeddertest.cpp
+++ b/fpdfsdk/fpdfsave_embeddertest.cpp
@@ -19,14 +19,14 @@ TEST_F(FPDFSaveEmbedderTest, SaveSimpleDoc) {
   EXPECT_TRUE(OpenDocument("hello_world.pdf"));
   EXPECT_TRUE(FPDF_SaveAsCopy(document(), this, 0));
   EXPECT_THAT(GetString(), testing::StartsWith("%PDF-1.7\r\n"));
-  EXPECT_EQ(843, GetString().length());
+  EXPECT_EQ(843u, GetString().length());
 }
 
 TEST_F(FPDFSaveEmbedderTest, SaveSimpleDocWithVersion) {
   EXPECT_TRUE(OpenDocument("hello_world.pdf"));
   EXPECT_TRUE(FPDF_SaveWithVersion(document(), this, 0, 14));
   EXPECT_THAT(GetString(), testing::StartsWith("%PDF-1.4\r\n"));
-  EXPECT_EQ(843, GetString().length());
+  EXPECT_EQ(843u, GetString().length());
 }
 
 TEST_F(FPDFSaveEmbedderTest, SaveSimpleDocWithBadVersion) {
diff --git a/fpdfsdk/fpdftext_embeddertest.cpp b/fpdfsdk/fpdftext_embeddertest.cpp
index ed20882a1b..a5215c20cc 100644
--- a/fpdfsdk/fpdftext_embeddertest.cpp
+++ b/fpdfsdk/fpdftext_embeddertest.cpp
@@ -48,7 +48,8 @@ TEST_F(FPDFTextEmbeddertest, Text) {
   EXPECT_TRUE(check_unsigned_shorts(expected, fixed_buffer, sizeof(expected)));
 
   // Count does not include the terminating NUL in the string literal.
-  EXPECT_EQ(sizeof(expected) - 1, FPDFText_CountChars(textpage));
+  EXPECT_EQ(sizeof(expected) - 1,
+            static_cast<size_t>(FPDFText_CountChars(textpage)));
   for (size_t i = 0; i < sizeof(expected) - 1; ++i) {
     EXPECT_EQ(static_cast<unsigned int>(expected[i]),
               FPDFText_GetUnicode(textpage, i))
@@ -285,6 +286,7 @@ TEST_F(FPDFTextEmbeddertest, WebLinks) {
   EXPECT_EQ(26, FPDFLink_GetURL(pagelink, 1, nullptr, 0));
 
   static const char expected_url[] = "http://example.com?q=foo";
+  static const size_t expected_len = sizeof(expected_url);
   unsigned short fixed_buffer[128];
 
   // Retrieve a link with too small a buffer.  Buffer will not be
@@ -297,30 +299,27 @@ TEST_F(FPDFTextEmbeddertest, WebLinks) {
 
   // Check buffer that doesn't have space for a terminating NUL.
   memset(fixed_buffer, 0xbd, sizeof(fixed_buffer));
-  EXPECT_EQ(
-      sizeof(expected_url) - 1,
-      FPDFLink_GetURL(pagelink, 0, fixed_buffer, sizeof(expected_url) - 1));
-  EXPECT_TRUE(check_unsigned_shorts(expected_url, fixed_buffer,
-                                    sizeof(expected_url) - 1));
-  EXPECT_EQ(0xbdbd, fixed_buffer[sizeof(expected_url) - 1]);
+  EXPECT_EQ(static_cast<int>(expected_len - 1),
+            FPDFLink_GetURL(pagelink, 0, fixed_buffer, expected_len - 1));
+  EXPECT_TRUE(
+      check_unsigned_shorts(expected_url, fixed_buffer, expected_len - 1));
+  EXPECT_EQ(0xbdbd, fixed_buffer[expected_len - 1]);
 
   // Retreive link with exactly-sized buffer.
   memset(fixed_buffer, 0xbd, sizeof(fixed_buffer));
-  EXPECT_EQ(sizeof(expected_url),
-            FPDFLink_GetURL(pagelink, 0, fixed_buffer, sizeof(expected_url)));
-  EXPECT_TRUE(
-      check_unsigned_shorts(expected_url, fixed_buffer, sizeof(expected_url)));
-  EXPECT_EQ(0u, fixed_buffer[sizeof(expected_url) - 1]);
-  EXPECT_EQ(0xbdbd, fixed_buffer[sizeof(expected_url)]);
+  EXPECT_EQ(static_cast<int>(expected_len),
+            FPDFLink_GetURL(pagelink, 0, fixed_buffer, expected_len));
+  EXPECT_TRUE(check_unsigned_shorts(expected_url, fixed_buffer, expected_len));
+  EXPECT_EQ(0u, fixed_buffer[expected_len - 1]);
+  EXPECT_EQ(0xbdbd, fixed_buffer[expected_len]);
 
   // Retreive link with ample-sized-buffer.
   memset(fixed_buffer, 0xbd, sizeof(fixed_buffer));
-  EXPECT_EQ(sizeof(expected_url),
+  EXPECT_EQ(static_cast<int>(expected_len),
             FPDFLink_GetURL(pagelink, 0, fixed_buffer, 128));
-  EXPECT_TRUE(
-      check_unsigned_shorts(expected_url, fixed_buffer, sizeof(expected_url)));
-  EXPECT_EQ(0u, fixed_buffer[sizeof(expected_url) - 1]);
-  EXPECT_EQ(0xbdbd, fixed_buffer[sizeof(expected_url)]);
+  EXPECT_TRUE(check_unsigned_shorts(expected_url, fixed_buffer, expected_len));
+  EXPECT_EQ(0u, fixed_buffer[expected_len - 1]);
+  EXPECT_EQ(0xbdbd, fixed_buffer[expected_len]);
 
   // Each link rendered in a single rect in this test page.
   EXPECT_EQ(1, FPDFLink_CountRects(pagelink, 0));
@@ -382,7 +381,7 @@ TEST_F(FPDFTextEmbeddertest, GetFontSize) {
                                         16, 16, 16, 16, 16, 16, 16, 16, 16, 16};
 
   int count = FPDFText_CountChars(textpage);
-  ASSERT_EQ(FX_ArraySize(kExpectedFontsSizes), count);
+  ASSERT_EQ(FX_ArraySize(kExpectedFontsSizes), static_cast<size_t>(count));
   for (int i = 0; i < count; ++i)
     EXPECT_EQ(kExpectedFontsSizes[i], FPDFText_GetFontSize(textpage, i)) << i;
 
diff --git a/fpdfsdk/fpdfview.cpp b/fpdfsdk/fpdfview.cpp
index 9995fc0426..9183b4073b 100644
--- a/fpdfsdk/fpdfview.cpp
+++ b/fpdfsdk/fpdfview.cpp
@@ -194,7 +194,8 @@ FX_BOOL CPDF_CustomAccess::ReadBlock(void* buffer,
   FX_SAFE_FILESIZE newPos =
       pdfium::base::checked_cast<FX_FILESIZE, size_t>(size);
   newPos += offset;
-  if (!newPos.IsValid() || newPos.ValueOrDie() > m_FileAccess.m_FileLen) {
+  if (!newPos.IsValid() ||
+      newPos.ValueOrDie() > static_cast<FX_FILESIZE>(m_FileAccess.m_FileLen)) {
     return FALSE;
   }
   return m_FileAccess.m_GetBlock(m_FileAccess.m_Param, offset, (uint8_t*)buffer,
diff --git a/fpdfsdk/fpdfview_embeddertest.cpp b/fpdfsdk/fpdfview_embeddertest.cpp
index 29eb91ab4d..10fe3aa822 100644
--- a/fpdfsdk/fpdfview_embeddertest.cpp
+++ b/fpdfsdk/fpdfview_embeddertest.cpp
@@ -88,14 +88,16 @@ TEST_F(FPDFViewEmbeddertest, NamedDests) {
   buffer_size = sizeof(fixed_buffer);
   dest = FPDF_GetNamedDest(document(), 2, fixed_buffer, &buffer_size);
   EXPECT_EQ(nullptr, dest);
-  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+  EXPECT_EQ(sizeof(fixed_buffer),
+            static_cast<size_t>(buffer_size));  // unmodified.
 
   // Try to retrieve the forth item with ample buffer. Item is taken
   // from Dests NameTree but has a vale of the wrong type in named_dests.pdf.
   buffer_size = sizeof(fixed_buffer);
   dest = FPDF_GetNamedDest(document(), 3, fixed_buffer, &buffer_size);
   EXPECT_EQ(nullptr, dest);
-  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+  EXPECT_EQ(sizeof(fixed_buffer),
+            static_cast<size_t>(buffer_size));  // unmodified.
 
   // Try to retrieve fifth item with ample buffer. Item taken from the
   // old-style Dests dictionary object in named_dests.pdf.
@@ -120,25 +122,29 @@ TEST_F(FPDFViewEmbeddertest, NamedDests) {
   buffer_size = sizeof(fixed_buffer);
   dest = FPDF_GetNamedDest(document(), 6, fixed_buffer, &buffer_size);
   EXPECT_EQ(nullptr, dest);
-  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+  EXPECT_EQ(sizeof(fixed_buffer),
+            static_cast<size_t>(buffer_size));  // unmodified.
 
   // Try to underflow/overflow the integer index.
   buffer_size = sizeof(fixed_buffer);
   dest = FPDF_GetNamedDest(document(), std::numeric_limits<int>::max(),
                            fixed_buffer, &buffer_size);
   EXPECT_EQ(nullptr, dest);
-  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+  EXPECT_EQ(sizeof(fixed_buffer),
+            static_cast<size_t>(buffer_size));  // unmodified.
 
   buffer_size = sizeof(fixed_buffer);
   dest = FPDF_GetNamedDest(document(), std::numeric_limits<int>::min(),
                            fixed_buffer, &buffer_size);
   EXPECT_EQ(nullptr, dest);
-  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+  EXPECT_EQ(sizeof(fixed_buffer),
+            static_cast<size_t>(buffer_size));  // unmodified.
 
   buffer_size = sizeof(fixed_buffer);
   dest = FPDF_GetNamedDest(document(), -1, fixed_buffer, &buffer_size);
   EXPECT_EQ(nullptr, dest);
-  EXPECT_EQ(sizeof(fixed_buffer), buffer_size);  // unmodified.
+  EXPECT_EQ(sizeof(fixed_buffer),
+            static_cast<size_t>(buffer_size));  // unmodified.
 }
 
 TEST_F(FPDFViewEmbeddertest, NamedDestsByName) {
diff --git a/fpdfsdk/javascript/Field.cpp b/fpdfsdk/javascript/Field.cpp
index 54b4f6432c..5b8750d88e 100644
--- a/fpdfsdk/javascript/Field.cpp
+++ b/fpdfsdk/javascript/Field.cpp
@@ -1014,7 +1014,7 @@ void Field::SetCurrentValueIndices(CPDFSDK_Document* pDocument,
       for (size_t i = 0; i < array.size(); ++i) {
         if (i != 0 && !(dwFieldFlags & (1 << 21)))
           break;
-        if (array[i] < pFormField->CountOptions() &&
+        if (array[i] < static_cast<uint32_t>(pFormField->CountOptions()) &&
             !pFormField->IsItemSelected(array[i])) {
           pFormField->SetItemSelection(array[i], TRUE);
         }
diff --git a/fpdfsdk/javascript/PublicMethods.cpp b/fpdfsdk/javascript/PublicMethods.cpp
index a4c13564c8..62659e4163 100644
--- a/fpdfsdk/javascript/PublicMethods.cpp
+++ b/fpdfsdk/javascript/PublicMethods.cpp
@@ -1502,7 +1502,7 @@ FX_BOOL CJS_PublicMethods::AFSpecial_KeystrokeEx(
   if (wChange.empty())
     return TRUE;
 
-  int iIndexMask = pEvent->SelStart();
+  size_t iIndexMask = pEvent->SelStart();
 
   size_t combined_len = wstrValue.length() + wChange.length() -
                         (pEvent->SelEnd() - pEvent->SelStart());