VFS: 1/5 - stream that

os/h3r_os.h

@@ -263,6 +263,8 @@ template <typename T> bool EnumFiles(T & c, const char * dn,
     return true;
 } // EnumFiles
 
+//LATER - per OS - get_process_path
+
 } // namespace OS
 NAMESPACE_H3R
 

stream/h3r_nostream.cpp

@@ -0,0 +1,41 @@
+/**** BEGIN LICENSE BLOCK ****
+
+BSD 3-Clause License
+
+Copyright (c) 2021-2023, the wind.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+**** END LICENCE BLOCK ****/
+
+#include "h3r_nostream.h"
+
+H3R_NAMESPACE
+
+Stream * Stream::NoStream() { static class NoStream s; return &s; }
+
+NAMESPACE_H3R

stream/h3r_nostream.h

@@ -0,0 +1,61 @@
+/**** BEGIN LICENSE BLOCK ****
+
+BSD 3-Clause License
+
+Copyright (c) 2021-2023, the wind.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+**** END LICENCE BLOCK ****/
+
+#ifndef _H3R_NOSTREAM_H_
+#define _H3R_NOSTREAM_H_
+
+#include "h3r_stream.h"
+
+H3R_NAMESPACE
+
+// A stream that does nothing, including not decorating anything.
+class NoStream final : public Stream
+{
+    public: NoStream() : Stream {} {}
+    public: NoStream(Stream * s) : Stream {s} {}
+    public: ~NoStream() override {}
+    public: inline operator bool() override { return false; }
+    public: inline Stream & Seek(off_t) override { return *this; }
+    public: inline off_t Tell() override { return 0; }
+    public: inline off_t Size() override { return 0; }
+    public: inline Stream & Read(void *, size_t) override { return *this; }
+    public: inline Stream & Write(const void *, size_t) override
+    {
+        return *this;
+    }
+};
+
+NAMESPACE_H3R
+
+#endif

stream/h3r_stream.h

@@ -41,10 +41,14 @@ H3R_NAMESPACE
 
 class Stream
 {
-    private: Stream * _f {};
+    // The book states the decorator shall differ the component, but it fails
+    // to give reason; so lets find out:
+    private: Stream * _f{};
 
-    public: Stream(Stream * s) : _f {s} {};
+    public: Stream(Stream * s) : _f{nullptr == s ? NoStream () : s} {}
+    protected: Stream() {} // no decorator constructor
     public: virtual ~Stream() {}
+    protected: static Stream * NoStream(); // no "if (_f)"
     protected: inline const Stream * BaseStream() const { return _f; }
 
     // true when the stream is ok

utils/h3r_vfs.cpp

@@ -36,18 +36,13 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 H3R_NAMESPACE
 
-VFS::VFS(String)
-{
-}
+VFS::VFS(const String &) {}
 
-VFS::~VFS()
-{
-}
+VFS::~VFS() {}
 
-Stream VFS::Get(String)
+Stream VFS::Get(const String &)
 {
-    Stream s {nullptr};
-    return s;
+    return static_cast<Stream &&>(Stream {nullptr});
 }
 
 NAMESPACE_H3R

utils/h3r_vfs.h

@@ -45,32 +45,15 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 H3R_NAMESPACE
 
-// Singleton. The 2nd instance will get you an exit() with an assertion failed.
-//
-// Access .mp3, .h3m, .h3c, .h3r (savegame), .wav, .pcx, .def, .txt, etc.
-// Currently this VFS is using the POSIX tolower() - and I have no idea how
-// it handles "Unicode", so unless I specifically find the time to enable
-// "unicode" support, consider ASCII to be the safe choice for your filenames.
-//
-// For in-game resources:
-// 1st the original VFS will be searched, and next the FS. The FS files can
-// override the VFS ones, but the names shall be distinct per FS.
-class VFS final
+//TODO unicode support,
+// Consider ASCII to be the safe choice for your filenames.
+class VFS
 {
-    // Due to case-sensitive FS-es, file enumeration shall be used to set the
-    // required game directories and file paths.
-    // The different ones: AB overrides when there is no SoD installed;
-    // SoD overrides otherwise, but - there are text files that has to be
-    // merged it seems? - see "vfs_info"
-    //TODO check with AB installed only
-
     public: enum class FileType {nvm,
         bik, def, fnt, h3c, h3m, h3r, mp3, msk, pal, pcx, smk, txt, wav};
 
-    // Best to get that from main()
-    //LATER - per OS - get_process_path
-    public: VFS(String process_dir);
-    public: ~VFS();
+    public: VFS(const String & path);
+    public: virtual ~VFS();
 
     // You request by name - you get a stream. You request the same name
     // again - you get another stream. What you do with the returned stream
@@ -83,9 +66,7 @@ class VFS final
     // use-case 1: on_game_start (cache all needed resources into RAM).
     // use-case 2: on_map_load (cache all needed resources into RAM).
     // use-case 3: on_map_load (invalidate, and do use-case #2)
-    // The role of this object is to abstract away data access - caching is
-    // not part of its duties.
-    public: Stream Get(String name);
+    public: virtual Stream Get(const String & name);
 };
 
 NAMESPACE_H3R