Miscellaneous code cleanup / modernization.

- Make liberal use of C++11 `override` and `final` specifiers.
- Replace various `typedef struct` with plain structs and `using` declarations.
- Change include hierarchy, now using dedicated forward declaration headers.
- Refactor (non-)portable portions of radiosity octree code, and add truly portable alternative implementations.
- Some odds and ends.

platform/unix/syspovfilesystem.cpp

@@ -0,0 +1,175 @@
+//******************************************************************************
+///
+/// @file platform/unix/syspovfilesystem.cpp
+///
+/// Unix-specific implementation of file system services.
+///
+/// @copyright
+/// @parblock
+///
+/// Persistence of Vision Ray Tracer ('POV-Ray') version 3.8.
+/// Copyright 1991-2019 Persistence of Vision Raytracer Pty. Ltd.
+///
+/// POV-Ray is free software: you can redistribute it and/or modify
+/// it under the terms of the GNU Affero General Public License as
+/// published by the Free Software Foundation, either version 3 of the
+/// License, or (at your option) any later version.
+///
+/// POV-Ray is distributed in the hope that it will be useful,
+/// but WITHOUT ANY WARRANTY; without even the implied warranty of
+/// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+/// GNU Affero General Public License for more details.
+///
+/// You should have received a copy of the GNU Affero General Public License
+/// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+///
+/// ----------------------------------------------------------------------------
+///
+/// POV-Ray is based on the popular DKB raytracer version 2.12.
+/// DKBTrace was originally written by David K. Buck.
+/// DKBTrace Ver 2.0-2.12 were written by David K. Buck & Aaron A. Collins.
+///
+/// @endparblock
+///
+//******************************************************************************
+
+// Unit header file must be the first file included within POV-Ray *.cpp files (pulls in config)
+#include "base/filesystem.h"
+#include "syspovfilesystem.h"
+
+// C++ variants of C standard header files
+//  (none at the moment)
+
+// C++ standard header files
+#include <limits>
+
+// POSIX standard header files
+#include <fcntl.h>
+#include <unistd.h>
+
+// POV-Ray header files (base module)
+#include "base/stringutilities.h"
+
+// this must be the last file included
+#include "base/povassert.h"
+#include "base/povdebug.h"
+
+namespace pov_base
+{
+
+namespace Filesystem
+{
+
+//******************************************************************************
+
+#if !POV_USE_DEFAULT_DELETEFILE
+
+bool DeleteFile(const UCS2String& fileName)
+{
+    return (unlink(UCS2toSysString(fileName).c_str()) == 0);
+}
+
+#endif // POV_USE_DEFAULT_DELETEFILE
+
+//******************************************************************************
+
+#if !POV_USE_DEFAULT_LARGEFILE
+
+#ifndef POVUNIX_LSEEK64
+#define POVUNIX_LSEEK64(h,b,o) lseek(h,b,o)
+#endif
+
+using Offset = decltype(POVUNIX_LSEEK64(0,0,0));
+
+static_assert(
+    std::numeric_limits<Offset>::digits > 32,
+    "Large files (> 2 GiB) not supported, limiting image size to approx. 100 Megapixels. Proceed at your own risk."
+    );
+
+struct LargeFile::Data final
+{
+    int handle;
+    Data() : handle(-1) {}
+};
+
+LargeFile::LargeFile() :
+    mpData(new Data)
+{}
+
+LargeFile::~LargeFile()
+{
+    Close();
+}
+
+bool LargeFile::CreateRW(const UCS2String& fileName)
+{
+    mpData->handle = open(UCS2toSysString(fileName).c_str(),
+                          O_CREAT | O_RDWR | O_TRUNC, S_IRUSR | S_IWUSR);
+    return (mpData->handle != -1);
+}
+
+bool LargeFile::Seek(std::int_least64_t offset)
+{
+    if (mpData->handle == -1)
+        return false;
+    if ((offset < 0) || (offset > std::numeric_limits<Offset>::max()))
+        return false;
+    return (POVUNIX_LSEEK64(mpData->handle, Offset(offset), SEEK_SET) == offset);
+}
+
+std::size_t LargeFile::Read(void* data, std::size_t maxSize)
+{
+    if (mpData->handle == -1)
+        return false;
+    return read(mpData->handle, data, int(maxSize));
+}
+
+bool LargeFile::Write(const void* data, std::size_t size)
+{
+    if (mpData->handle == -1)
+        return false;
+    return (write(mpData->handle, data, int(size)) == size);
+}
+
+void LargeFile::Close()
+{
+    if (mpData->handle != -1)
+    {
+        close(mpData->handle);
+        mpData->handle = -1;
+    }
+}
+
+#endif // POV_USE_DEFAULT_LARGEFILE
+
+//******************************************************************************
+
+#if !POV_USE_DEFAULT_TEMPORARYFILE
+
+static UCS2String gTempPath;
+
+void SetTempFilePath(const UCS2String& tempPath)
+{
+    gTempPath = tempPath;
+}
+
+UCS2String TemporaryFile::SuggestName()
+{
+    POV_ASSERT(!gTempPath.empty());
+
+    // TODO FIXME - This allows only one temporary file per process!
+    // TODO FIXME - Avoid converting back and forth between UCS-2 and system-specific encoding.
+    char str [POV_FILENAME_BUFFER_CHARS + 1] = "";
+    std::snprintf(str, POV_FILENAME_BUFFER_CHARS + 1, "%spov%d", UCS2toSysString(gTempPath).c_str(), int(getpid()));
+    return SysToUCS2String(str);
+}
+
+#endif // POV_USE_DEFAULT_TEMPORARYFILE
+
+//******************************************************************************
+
+}
+// end of namespace Filesystem
+
+}
+// end of namespace pov_base

platform/unix/syspovfilesystem.h

@@ -0,0 +1,72 @@
+//******************************************************************************
+///
+/// @file platform/unix/syspovfilesystem.h
+///
+/// Unix-specific declarations related to file system services.
+///
+/// @note
+///     Most of @ref platform/unix/syspovfilesystem.cpp is declared in
+///     @ref base/filesystem.h. This file contains only a few extra
+///     platform-specific declarations.
+///
+/// @copyright
+/// @parblock
+///
+/// Persistence of Vision Ray Tracer ('POV-Ray') version 3.8.
+/// Copyright 1991-2019 Persistence of Vision Raytracer Pty. Ltd.
+///
+/// POV-Ray is free software: you can redistribute it and/or modify
+/// it under the terms of the GNU Affero General Public License as
+/// published by the Free Software Foundation, either version 3 of the
+/// License, or (at your option) any later version.
+///
+/// POV-Ray is distributed in the hope that it will be useful,
+/// but WITHOUT ANY WARRANTY; without even the implied warranty of
+/// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+/// GNU Affero General Public License for more details.
+///
+/// You should have received a copy of the GNU Affero General Public License
+/// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+///
+/// ----------------------------------------------------------------------------
+///
+/// POV-Ray is based on the popular DKB raytracer version 2.12.
+/// DKBTrace was originally written by David K. Buck.
+/// DKBTrace Ver 2.0-2.12 were written by David K. Buck & Aaron A. Collins.
+///
+/// @endparblock
+///
+//******************************************************************************
+
+#ifndef POVRAY_UNIX_SYSPOVFILESYSTEM_H
+#define POVRAY_UNIX_SYSPOVFILESYSTEM_H
+
+// Module config header file must be the first file included within POV-Ray unit header files
+#include "base/configbase.h"
+
+// C++ variants of C standard header files
+// C++ standard header files
+//  (none at the moment)
+
+// POV-Ray header files (base module)
+#include "base/stringtypes.h"
+
+namespace pov_base
+{
+
+namespace Filesystem
+{
+
+#if !POV_USE_DEFAULT_TEMPORARYFILE
+
+void SetTempFilePath(const UCS2String& tempPath);
+
+#endif // POV_USE_DEFAULT_TEMPORARYFILE
+
+}
+// end of namespace Filesystem
+
+}
+// end of namespace pov_base
+
+#endif // POVRAY_UNIX_SYSPOVFILESYSTEM_H

platform/unix/syspovtimer.cpp

@@ -9,7 +9,7 @@
 /// @parblock
 ///
 /// Persistence of Vision Ray Tracer ('POV-Ray') version 3.8.
-/// Copyright 1991-2018 Persistence of Vision Raytracer Pty. Ltd.
+/// Copyright 1991-2019 Persistence of Vision Raytracer Pty. Ltd.
 ///
 /// POV-Ray is free software: you can redistribute it and/or modify
 /// it under the terms of the GNU Affero General Public License as
@@ -50,6 +50,7 @@
 #include <sys/time.h>
 #endif
 
+#include "base/povassert.h"
 #include "base/types.h"
 
 // this must be the last file included
@@ -305,3 +306,4 @@ bool Timer::HasValidThreadCPUTime () const
 //******************************************************************************
 
 }
+// end of namespace pov_base

platform/unix/syspovtimer.h

@@ -9,7 +9,7 @@
 /// @parblock
 ///
 /// Persistence of Vision Ray Tracer ('POV-Ray') version 3.8.
-/// Copyright 1991-2017 Persistence of Vision Raytracer Pty. Ltd.
+/// Copyright 1991-2019 Persistence of Vision Raytracer Pty. Ltd.
 ///
 /// POV-Ray is free software: you can redistribute it and/or modify
 /// it under the terms of the GNU Affero General Public License as
@@ -62,7 +62,7 @@ void Delay(unsigned int msec);
 ///     in the order of an hour (any system with a 32-bit `clock_t` and a standard `CLOCKS_PER_SEC`
 ///     of 1,000,000).
 ///
-class Timer
+class Timer final
 {
     public:
 
@@ -105,5 +105,6 @@ class Timer
 #endif // !POV_USE_DEFAULT_TIMER
 
 }
+// end of namespace pov_base
 
 #endif // POVRAY_UNIX_SYSPOVTIMER_H

platform/windows/osversioninfo.cpp

@@ -8,7 +8,7 @@
 /// @parblock
 ///
 /// Persistence of Vision Ray Tracer ('POV-Ray') version 3.8.
-/// Copyright 1991-2017 Persistence of Vision Raytracer Pty. Ltd.
+/// Copyright 1991-2019 Persistence of Vision Raytracer Pty. Ltd.
 ///
 /// POV-Ray is free software: you can redistribute it and/or modify
 /// it under the terms of the GNU Affero General Public License as
@@ -60,3 +60,4 @@ bool WindowsVersionDetector::IsVersion (int major, int minor) const
 }
 
 }
+// end of namespace pov_base

platform/windows/osversioninfo.h

@@ -8,7 +8,7 @@
 /// @parblock
 ///
 /// Persistence of Vision Ray Tracer ('POV-Ray') version 3.8.
-/// Copyright 1991-2017 Persistence of Vision Raytracer Pty. Ltd.
+/// Copyright 1991-2019 Persistence of Vision Raytracer Pty. Ltd.
 ///
 /// POV-Ray is free software: you can redistribute it and/or modify
 /// it under the terms of the GNU Affero General Public License as
@@ -43,7 +43,7 @@
 namespace pov_base
 {
 
-class WindowsVersionDetector
+class WindowsVersionDetector final
 {
     public:
 
@@ -74,5 +74,6 @@ class WindowsVersionDetector
 };
 
 }
+// end of namespace pov_base
 
 #endif // POVRAY_WINDOWS_OSVERSIONINFO_H