in the attempt to fix 627393, changed IFX_FileRead's readBlock to return the length it reads

xfa/fgas/crt/fgas_stream.cpp

Index: xfa/fgas/crt/fgas_stream.cpp
diff --git a/xfa/fgas/crt/fgas_stream.cpp b/xfa/fgas/crt/fgas_stream.cpp
index 74c19eab32f614f67128dff070d8577a0ae925ab..155a63a921395860691f7c010ed7d9c426a4d90b 100644
--- a/xfa/fgas/crt/fgas_stream.cpp
+++ b/xfa/fgas/crt/fgas_stream.cpp
@@ -296,12 +296,14 @@ class CFGAS_FileRead : public IFX_FileRead {
 
   // IFX_FileRead
   void Release() override;
+  FX_BOOL IsEOF() override;
   FX_FILESIZE GetSize() override;
-  FX_BOOL ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override;
+  size_t ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override;
 
  protected:
   FX_BOOL m_bReleaseStream;
   IFX_Stream* m_pStream;
+  FX_FILESIZE m_nCurPos;
 };
 
 int32_t FileLength(FXSYS_FILE* file) {
@@ -590,7 +592,9 @@ int32_t CFX_FileReadStreamImp::ReadData(uint8_t* pBuffer, int32_t iBufferSize) {
   if (iBufferSize > m_iLength - m_iPosition) {
     iBufferSize = m_iLength - m_iPosition;
   }
-  if (m_pFileRead->ReadBlock(pBuffer, m_iPosition, iBufferSize)) {
+  if (m_pFileRead->ReadBlock(pBuffer, m_iPosition, iBufferSize) ==
+          iBufferSize ||
+      m_pFileRead->IsEOF()) {
     m_iPosition += iBufferSize;
     return iBufferSize;
   }
@@ -1473,7 +1477,7 @@ IFX_FileRead* FX_CreateFileRead(IFX_Stream* pBaseStream,
   return new CFGAS_FileRead(pBaseStream, bReleaseStream);
 }
 CFGAS_FileRead::CFGAS_FileRead(IFX_Stream* pStream, FX_BOOL bReleaseStream)
-    : m_bReleaseStream(bReleaseStream), m_pStream(pStream) {
+    : m_bReleaseStream(bReleaseStream), m_pStream(pStream), m_nCurPos(0) {
   ASSERT(m_pStream);
 }
 CFGAS_FileRead::~CFGAS_FileRead() {
@@ -1481,15 +1485,19 @@ CFGAS_FileRead::~CFGAS_FileRead() {
     m_pStream->Release();
   }
 }
+FX_BOOL CFGAS_FileRead::IsEOF() {
+  return m_nCurPos >= (FX_FILESIZE)m_pStream->GetLength();
+}
 FX_FILESIZE CFGAS_FileRead::GetSize() {
   return (FX_FILESIZE)m_pStream->GetLength();
 }
-FX_BOOL CFGAS_FileRead::ReadBlock(void* buffer,
-                                  FX_FILESIZE offset,
-                                  size_t size) {
+size_t CFGAS_FileRead::ReadBlock(void* buffer,
+                                 FX_FILESIZE offset,
+                                 size_t size) {
   m_pStream->Seek(FX_STREAMSEEK_Begin, (int32_t)offset);
   int32_t iLen = m_pStream->ReadData((uint8_t*)buffer, (int32_t)size);
-  return iLen == (int32_t)size;
+  m_nCurPos = offset + iLen;
+  return iLen;
 }
 
 void CFGAS_FileRead::Release() {