Add some asserts to ensure cols and rows are >= 0 to avoid crashes

[wxWidgets.git] / src / common / file.cpp

diff --git a/src/common/file.cpp b/src/common/file.cpp
index a6d96d6a8ed45e6625c4a0ce17bfd46a3850033b..bd4a4f0a0c3dc3567ef67b15c2d897836b5d4df7 100644 (file)
--- a/src/common/file.cpp
+++ b/src/common/file.cpp
@@ -312,7 +312,12 @@ bool wxFile::Write(const wxString& s, const wxMBConv& conv)
   if ( !buf )
       return false;
 
-  const size_t size = strlen(buf); // FIXME: use buf.length() when available
+#if wxUSE_UNICODE
+  const size_t size = buf.length();
+#else
+  const size_t size = s.length();
+#endif
+
   return Write(buf, size) == size;
 }
 
@@ -342,15 +347,15 @@ bool wxFile::Flush()
 // seek
 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 {
-    wxASSERT_MSG( IsOpened(), _T("can't seek on closed file") );
+    wxASSERT_MSG( IsOpened(), wxT("can't seek on closed file") );
     wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
                  wxInvalidOffset,
-                 _T("invalid absolute file offset") );
+                 wxT("invalid absolute file offset") );
 
     int origin;
     switch ( mode ) {
         default:
-            wxFAIL_MSG(_T("unknown seek origin"));
+            wxFAIL_MSG(wxT("unknown seek origin"));
 
         case wxFromStart:
             origin = SEEK_SET;
@@ -393,10 +398,24 @@ wxFileOffset wxFile::Length() const
 {
     wxASSERT( IsOpened() );
 
+    // we use a special method for Linux systems where files in sysfs (i.e.
+    // those under /sys typically) return length of 4096 bytes even when
+    // they're much smaller -- this is a problem as it results in errors later
+    // when we try reading 4KB from them
+#ifdef __LINUX__
+    struct stat st;
+    if ( fstat(m_fd, &st) == 0 )
+    {
+        // returning 0 for the special files indicates to the caller that they
+        // are not seekable
+        return st.st_blocks ? st.st_size : 0;
+    }
+    //else: failed to stat, try the normal method
+#endif // __LINUX__
+
     wxFileOffset iRc = Tell();
     if ( iRc != wxInvalidOffset ) {
-        // have to use const_cast :-(
-        wxFileOffset iLen = ((wxFile *)this)->SeekEnd();
+        wxFileOffset iLen = const_cast<wxFile *>(this)->SeekEnd();
         if ( iLen != wxInvalidOffset ) {
             // restore old position
             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
@@ -435,14 +454,17 @@ bool wxFile::Eof() const
     iRc = wxEof(m_fd);
 #endif // Windows/Unix
 
-    if ( iRc == 1)
-        {}
-    else if ( iRc == 0 )
+    if ( iRc == 0 )
         return false;
-    else if ( iRc == wxInvalidOffset )
+
+    if ( iRc == wxInvalidOffset )
+    {
         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
-    else
-        wxFAIL_MSG(_T("invalid eof() return value."));
+    }
+    else if ( iRc != 1 )
+    {
+        wxFAIL_MSG(wxT("invalid eof() return value."));
+    }
 
     return true;
 }
@@ -545,7 +567,9 @@ void wxTempFile::Discard()
 {
     m_file.Close();
     if ( wxRemove(m_strTemp) != 0 )
+    {
         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
+    }
 }
 
 #endif // wxUSE_FILE