Returns int64 value in function of seeking to file end on x64 Windows. (

#1057)
microsoft · Mar 15, 2019 · 3f6f844 · 3f6f844
1 parent 572ab7c
commit 3f6f844
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Showing 2 changed files with 23 additions and 1 deletion.
diff --git a/Release/include/cpprest/filestream.h b/Release/include/cpprest/filestream.h
@@ -649,12 +649,19 @@ class basic_file_buffer : public details::streambuf_state_manager<_CharType>
         if (mode == std::ios_base::in)
         {
             m_readOps.wait();
+            size_t current_pos = static_cast<size_t>(-1);
             switch (way)
             {
                 case std::ios_base::beg: return (pos_type)_seekrdpos_fsb(m_info, size_t(offset), sizeof(_CharType));
                 case std::ios_base::cur:
                     return (pos_type)_seekrdpos_fsb(m_info, size_t(m_info->m_rdpos + offset), sizeof(_CharType));
-                case std::ios_base::end: return (pos_type)_seekrdtoend_fsb(m_info, int64_t(offset), sizeof(_CharType));
+                case std::ios_base::end:
+                    current_pos = _seekrdtoend_fsb(m_info, int64_t(offset), sizeof(_CharType));
+                    if (current_pos == static_cast<size_t>(-1))
+                    {
+                        return -1;
+                    }
+                    return (pos_type)current_pos;
                 default:
                     // Fail on invalid input (_S_ios_seekdir_end)
                     assert(false);

diff --git a/Release/src/streams/fileio_win32.cpp b/Release/src/streams/fileio_win32.cpp
@@ -905,11 +905,26 @@ size_t __cdecl _seekrdtoend_fsb(_In_ streams::details::_file_info* info, int64_t
         fInfo->m_bufoff = fInfo->m_buffill = fInfo->m_bufsize = 0;
     }
 
+#ifdef _WIN64
+    LARGE_INTEGER filesize;
+    filesize.QuadPart = 0;
+
+    BOOL result = GetFileSizeEx(fInfo->m_handle, &filesize);
+    if (FALSE == result)
+    {
+        return static_cast<size_t>(-1);
+    }
+    else
+    {
+        fInfo->m_rdpos = static_cast<size_t>(filesize.QuadPart) / char_size;
+    }
+#else
     auto newpos = SetFilePointer(fInfo->m_handle, (LONG)(offset * char_size), nullptr, FILE_END);
 
     if (newpos == INVALID_SET_FILE_POINTER) return static_cast<size_t>(-1);
 
     fInfo->m_rdpos = static_cast<size_t>(newpos) / char_size;
+#endif
 
     return fInfo->m_rdpos;
 }