Add StreamRWops class

CMakeLists.txt

@@ -79,6 +79,7 @@ SET(LIBRARY_HEADERS
 	SDL2pp/Renderer.hh
 	SDL2pp/SDL.hh
 	SDL2pp/SDL2pp.hh
+	SDL2pp/StreamRWops.hh
 	SDL2pp/Texture.hh
 	SDL2pp/Wav.hh
 	SDL2pp/Window.hh

SDL2pp/SDL2pp.hh

@@ -34,6 +34,7 @@
 #include <SDL2pp/Point.hh>
 #include <SDL2pp/RWops.hh>
 #include <SDL2pp/ContainerRWops.hh>
+#include <SDL2pp/StreamRWops.hh>
 #include <SDL2pp/Wav.hh>
 
 #endif

SDL2pp/StreamRWops.hh

@@ -0,0 +1,100 @@
+/*
+  libSDL2pp - C++11 bindings/wrapper for SDL2
+  Copyright (C) 2014 Dmitry Marakasov <amdmi3@amdmi3.ru>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef SDL2PP_STREAMRWOPS_HH
+#define SDL2PP_STREAMRWOPS_HH
+
+#include <SDL2pp/RWops.hh>
+
+#include <stdexcept>
+#include <iostream>
+
+namespace SDL2pp {
+
+template<typename S>
+class StreamRWops : public CustomRWops {
+protected:
+	S& stream_;
+
+public:
+	StreamRWops(const S& stream) : stream_(stream) {
+	}
+
+	StreamRWops(const StreamRWops<S>&) = default;
+	StreamRWops& operator=(const StreamRWops<S>&) = delete;
+	StreamRWops(StreamRWops<S>&&) noexcept = default;
+	StreamRWops& operator=(StreamRWops<S>&&) = delete;
+
+	virtual Sint64 Seek(Sint64 offset, int whence) override {
+		switch (whence) {
+		case RW_SEEK_SET:
+			stream_.seekg(offset, std::ios_base::beg);
+			break;
+		case RW_SEEK_CUR:
+			stream_.seekg(offset, std::ios_base::cur);
+			break;
+		case RW_SEEK_END:
+			stream_.seekg(offset, std::ios_base::end);
+			break;
+		default:
+			throw Exception("Unexpected whence value for StreamRWops::Seek");
+		}
+		return stream_.tellg();
+	}
+
+	virtual size_t Read(void* ptr, size_t size, size_t maxnum) override {
+		stream_.read(ptr, size * maxnum);
+		size_t nread = stream_.gcount();
+
+		if (nread != size * maxnum) {
+			// short read
+			unsigned char* pos = static_cast<unsigned char*>(ptr);
+			pos += nread + 1;
+
+			int count = nread % size;
+
+			// put partially read object back into the stream
+			while (--count >= 0)
+				stream_.putback(*--pos);
+
+			stream_.seekg(-count, std::ios_base::cur);
+		}
+		return nread / size;
+	}
+
+	virtual size_t Write(const void* ptr, size_t size, size_t maxnum) override {
+		stream_.write(ptr, size * maxnum);
+		// XXX: there seem to be no reliable way to tell how much
+		// was actually written
+		if (stream_.restate() & std::ios_base::badbit)
+			return 0;
+		return maxnum;
+	}
+
+	virtual int Close() override {
+		stream_.flush();
+		return stream_.restate() & std::ios_base::badbit;
+	}
+};
+
+}
+
+#endif

tests/CMakeLists.txt

@@ -9,6 +9,7 @@ SET(HEADER_TESTS
 	header_renderer
 	header_rwops
 	header_containerrwops
+	header_streamrwops
 	header_sdl
 	header_sdl2pp
 	header_texture

tests/header_streamrwops.cc

@@ -0,0 +1,5 @@
+#include <SDL2pp/StreamRWops.hh>
+
+int main() {
+	return 0;
+}