Relax checks added in commit 8f3a311.chromium/2760chromium/2759chromium/2758chromium/2757chromium/2756

Some shading types do not use these fields.

Review-Url: https://codereview.chromium.org/2027053002

3 files changed, 63 insertions, 31 deletions

diff --git a/core/fpdfapi/fpdf_page/cpdf_meshstream.cpp b/core/fpdfapi/fpdf_page/cpdf_meshstream.cpp
index d3649a1fdc..1d9c56046a 100644
--- a/core/fpdfapi/fpdf_page/cpdf_meshstream.cpp
+++ b/core/fpdfapi/fpdf_page/cpdf_meshstream.cpp
@@ -13,6 +13,19 @@
 namespace {
 
 // See PDF Reference 1.7, page 315, table 4.32. (Also table 4.33 and 4.34)
+bool ShouldCheckBPC(ShadingType type) {
+  switch (type) {
+    case kFreeFormGouraudTriangleMeshShading:
+    case kLatticeFormGouraudTriangleMeshShading:
+    case kCoonsPatchMeshShading:
+    case kTensorProductPatchMeshShading:
+      return true;
+    default:
+      return false;
+  }
+}
+
+// Same references as ShouldCheckBPC() above.
 bool IsValidBitsPerComponent(uint32_t x) {
   switch (x) {
     case 1:
@@ -27,7 +40,7 @@ bool IsValidBitsPerComponent(uint32_t x) {
   }
 }
 
-// Same references as IsValidBitsPerComponent() above.
+// Same references as ShouldCheckBPC() above.
 bool IsValidBitsPerCoordinate(uint32_t x) {
   switch (x) {
     case 1:
@@ -78,43 +91,60 @@ CPDF_MeshStream::CPDF_MeshStream(
     : m_type(type),
       m_funcs(funcs),
       m_pShadingStream(pShadingStream),
-      m_pCS(pCS) {}
+      m_pCS(pCS),
+      m_nCoordBits(0),
+      m_nComponentBits(0),
+      m_nFlagBits(0),
+      m_nComponents(0),
+      m_CoordMax(0),
+      m_ComponentMax(0),
+      m_xmin(0),
+      m_xmax(0),
+      m_ymin(0),
+      m_ymax(0) {
+  memset(&m_ColorMin, 0, sizeof(m_ColorMin));
+  memset(&m_ColorMax, 0, sizeof(m_ColorMax));
+}
 
 bool CPDF_MeshStream::Load() {
   m_Stream.LoadAllData(m_pShadingStream);
   m_BitStream.Init(m_Stream.GetData(), m_Stream.GetSize());
   CPDF_Dictionary* pDict = m_pShadingStream->GetDict();
   m_nCoordBits = pDict->GetIntegerBy("BitsPerCoordinate");
-  if (!IsValidBitsPerCoordinate(m_nCoordBits))
-    return false;
-
-  m_nCompBits = pDict->GetIntegerBy("BitsPerComponent");
-  if (!IsValidBitsPerComponent(m_nCompBits))
-    return false;
+  m_nComponentBits = pDict->GetIntegerBy("BitsPerComponent");
+  if (ShouldCheckBPC(m_type)) {
+    if (!IsValidBitsPerCoordinate(m_nCoordBits))
+      return false;
+    if (!IsValidBitsPerComponent(m_nComponentBits))
+      return false;
+  }
 
   m_nFlagBits = pDict->GetIntegerBy("BitsPerFlag");
   if (ShouldCheckBitsPerFlag(m_type) && !IsValidBitsPerFlag(m_nFlagBits))
     return false;
 
-  uint32_t nComps = m_pCS->CountComponents();
-  if (nComps > 8)
+  uint32_t nComponents = m_pCS->CountComponents();
+  if (nComponents > kMaxComponents)
     return false;
 
-  m_nComps = m_funcs.empty() ? nComps : 1;
-  m_CoordMax = m_nCoordBits == 32 ? -1 : (1 << m_nCoordBits) - 1;
-  m_CompMax = (1 << m_nCompBits) - 1;
+  m_nComponents = m_funcs.empty() ? nComponents : 1;
   CPDF_Array* pDecode = pDict->GetArrayBy("Decode");
-  if (!pDecode || pDecode->GetCount() != 4 + m_nComps * 2)
+  if (!pDecode || pDecode->GetCount() != 4 + m_nComponents * 2)
     return false;
 
   m_xmin = pDecode->GetNumberAt(0);
   m_xmax = pDecode->GetNumberAt(1);
   m_ymin = pDecode->GetNumberAt(2);
   m_ymax = pDecode->GetNumberAt(3);
-  for (uint32_t i = 0; i < m_nComps; ++i) {
+  for (uint32_t i = 0; i < m_nComponents; ++i) {
     m_ColorMin[i] = pDecode->GetNumberAt(i * 2 + 4);
     m_ColorMax[i] = pDecode->GetNumberAt(i * 2 + 5);
   }
+
+  if (ShouldCheckBPC(m_type)) {
+    m_CoordMax = m_nCoordBits == 32 ? -1 : (1 << m_nCoordBits) - 1;
+    m_ComponentMax = (1 << m_nComponentBits) - 1;
+  }
   return true;
 }
 
@@ -124,6 +154,7 @@ uint32_t CPDF_MeshStream::GetFlag() {
 }
 
 void CPDF_MeshStream::GetCoords(FX_FLOAT& x, FX_FLOAT& y) {
+  ASSERT(ShouldCheckBPC(m_type));
   if (m_nCoordBits == 32) {
     x = m_xmin + (FX_FLOAT)(m_BitStream.GetBits(m_nCoordBits) *
                             (m_xmax - m_xmin) / (double)m_CoordMax);
@@ -138,22 +169,23 @@ void CPDF_MeshStream::GetCoords(FX_FLOAT& x, FX_FLOAT& y) {
 }
 
 void CPDF_MeshStream::GetColor(FX_FLOAT& r, FX_FLOAT& g, FX_FLOAT& b) {
-  FX_FLOAT color_value[kMaxResults];
-  for (uint32_t i = 0; i < m_nComps; ++i) {
+  ASSERT(ShouldCheckBPC(m_type));
+  FX_FLOAT color_value[kMaxComponents];
+  for (uint32_t i = 0; i < m_nComponents; ++i) {
     color_value[i] = m_ColorMin[i] +
-                     m_BitStream.GetBits(m_nCompBits) *
-                         (m_ColorMax[i] - m_ColorMin[i]) / m_CompMax;
+                     m_BitStream.GetBits(m_nComponentBits) *
+                         (m_ColorMax[i] - m_ColorMin[i]) / m_ComponentMax;
   }
   if (m_funcs.empty()) {
     m_pCS->GetRGB(color_value, r, g, b);
     return;
   }
 
-  FX_FLOAT result[kMaxResults];
+  FX_FLOAT result[kMaxComponents];
   FXSYS_memset(result, 0, sizeof(result));
   int nResults;
   for (const auto& func : m_funcs) {
-    if (func && func->CountOutputs() <= kMaxResults)
+    if (func && func->CountOutputs() <= kMaxComponents)
       func->Call(color_value, 1, result, nResults);
   }
   m_pCS->GetRGB(result, r, g, b);
diff --git a/core/fpdfapi/fpdf_page/cpdf_meshstream.h b/core/fpdfapi/fpdf_page/cpdf_meshstream.h
index 8f47265acd..b8a8c38f37 100644
--- a/core/fpdfapi/fpdf_page/cpdf_meshstream.h
+++ b/core/fpdfapi/fpdf_page/cpdf_meshstream.h
@@ -47,28 +47,28 @@ class CPDF_MeshStream {
                        CFX_Matrix* pObject2Bitmap);
 
   CFX_BitStream* BitStream() { return &m_BitStream; }
-  uint32_t CompBits() const { return m_nCompBits; }
-  uint32_t comps() const { return m_nComps; }
+  uint32_t ComponentBits() const { return m_nComponentBits; }
+  uint32_t Components() const { return m_nComponents; }
 
  private:
-  static const uint32_t kMaxResults = 8;
+  static const uint32_t kMaxComponents = 8;
 
   const ShadingType m_type;
   const std::vector<std::unique_ptr<CPDF_Function>>& m_funcs;
   CPDF_Stream* const m_pShadingStream;
   CPDF_ColorSpace* const m_pCS;
   uint32_t m_nCoordBits;
-  uint32_t m_nCompBits;
+  uint32_t m_nComponentBits;
   uint32_t m_nFlagBits;
-  uint32_t m_nComps;
+  uint32_t m_nComponents;
   uint32_t m_CoordMax;
-  uint32_t m_CompMax;
+  uint32_t m_ComponentMax;
   FX_FLOAT m_xmin;
   FX_FLOAT m_xmax;
   FX_FLOAT m_ymin;
   FX_FLOAT m_ymax;
-  FX_FLOAT m_ColorMin[kMaxResults];
-  FX_FLOAT m_ColorMax[kMaxResults];
+  FX_FLOAT m_ColorMin[kMaxComponents];
+  FX_FLOAT m_ColorMax[kMaxComponents];
   CPDF_StreamAcc m_Stream;
   CFX_BitStream m_BitStream;
 };
diff --git a/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index 0592c97176..52576043e3 100644
--- a/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -146,8 +146,8 @@ CFX_FloatRect GetShadingBBox(CPDF_ShadingPattern* pShading,
         bStarted = true;
       }
     }
-    FX_SAFE_UINT32 nBits = stream.comps();
-    nBits *= stream.CompBits();
+    FX_SAFE_UINT32 nBits = stream.Components();
+    nBits *= stream.ComponentBits();
     nBits *= color_count;
     if (!nBits.IsValid())
       break;