From 5095c2e2ba9aadf468514804fb3a872d10fdc17d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Tue, 16 Aug 2022 04:37:48 +0200
Subject: Implement preliminary IO.

It might be a good idea to eschew the structs and access the data
directly from the view.

Alternatively, the serialization functions might be rewritten to
simply memcpy the structs, after either adding __attribute__((packed))
or ensuring consistent padding.
---
 c/data.cpp | 36 ++++++++++++++++++++++++++++++++++++
 c/data.h   | 10 ++++++++++
 c/test.cpp | 31 +++++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+)

(limited to 'c')

diff --git a/c/data.cpp b/c/data.cpp
index e28378e..1a78ef2 100644
--- a/c/data.cpp
+++ b/c/data.cpp
@@ -1,6 +1,8 @@
 #include <memory>
+#include <vector>
 
 #include "data.h"
+#include "win.h"
 
 template <typename T>
 inline unsigned char* ValToBuf(const T& val, unsigned char* const buf)
@@ -16,6 +18,40 @@ inline unsigned char* BufToVal(unsigned char* const buf, T& val)
 	return buf+sizeof(val);
 }
 
+DatView::DatView(const wchar_t* const filename, const size_t cb)
+{
+	hf = CreateFile(filename, GENERIC_READ|GENERIC_WRITE,
+	    0, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
+	if (hf == INVALID_HANDLE_VALUE) {
+		if (GetLastError() == ERROR_FILE_NOT_FOUND) {
+			hf = CreateFile(filename, GENERIC_READ|GENERIC_WRITE,
+			    0, nullptr, CREATE_NEW, FILE_ATTRIBUTE_NORMAL, nullptr);
+			if (hf == INVALID_HANDLE_VALUE)
+				throw Win32Error{};
+		} else
+			throw Win32Error{};
+	}
+
+	LARGE_INTEGER cbMap;
+	cbMap.QuadPart = cb;
+	hm = CreateFileMapping(hf, nullptr, PAGE_READWRITE,
+	    cbMap.HighPart, cbMap.LowPart, nullptr);
+	if (!hm)
+		throw Win32Error{};
+
+	view = MapViewOfFile(hm, FILE_MAP_ALL_ACCESS, 0, 0, 0);
+	if (!view)
+		throw Win32Error{};
+}
+
+DatView::~DatView()
+{
+	FlushViewOfFile(view, 0);
+	UnmapViewOfFile(view);
+	CloseHandle(hm);
+	CloseHandle(hf);
+}
+
 unsigned char* Serialize(const ElvData& e, unsigned char* buf)
 {
 	unsigned char version = 'a';
diff --git a/c/data.h b/c/data.h
index 797271d..91e34d9 100644
--- a/c/data.h
+++ b/c/data.h
@@ -24,6 +24,16 @@ struct DlvData
 	wchar_t wiki[128] = {0};
 };
 
+struct DatView
+{
+	DatView(const wchar_t* filename, size_t cb);
+	~DatView();
+	HANDLE hf;
+	HANDLE hm;
+	void* view;
+	/* TODO: Handle exceptions on read and write... */
+};
+
 constexpr size_t CB_SERIALIZE_ELVDATA = 1+sizeof(ElvData);
 unsigned char* Serialize(const ElvData& e, unsigned char* buf);
 unsigned char* Unserialize(ElvData& e, unsigned char* buf);
diff --git a/c/test.cpp b/c/test.cpp
index 1fc7e3b..fb5d44d 100644
--- a/c/test.cpp
+++ b/c/test.cpp
@@ -71,6 +71,36 @@ TESTS
 		if (wcscmp(e1.title, e2.title) != 0)
 			FAIL("title is different");
 	}
+
+	TEST(SerializationPlusIO)
+	{
+		ElvData e1;
+		FromProlog(6, e1);
+		{
+			DatView dv{L"tmp.dat", CB_SERIALIZE_ELVDATA};
+			Serialize(e1, static_cast<unsigned char*>(dv.view));
+		}
+		{
+			DatView dv{L"tmp.dat", CB_SERIALIZE_ELVDATA};
+
+			ElvData e2;
+			if (!Unserialize(e2, static_cast<unsigned char*>(dv.view)))
+				FAIL("invalid serialization version");
+			if (e1.rating != e2.rating)
+				FAIL("rating is different");
+			if (e1.bWatched != e2.bWatched)
+				FAIL("bWatched is different");
+			if (e1.bTVOriginal != e2.bTVOriginal)
+				FAIL("bTVOriginal is different");
+			if (wcscmp(e1.sRating, e2.sRating) != 0)
+				FAIL("sRating is different");
+			if (wcscmp(e1.siEp, e2.siEp) != 0)
+				FAIL("siEp is different");
+			if (wcscmp(e1.title, e2.title) != 0)
+				FAIL("title is different");
+		}
+		DeleteFile(L"tmp.dat");
+	}
 };
 
 int RunTests()
@@ -80,6 +110,7 @@ int RunTests()
 		//EpisodeDataFromWeb{},
 		EpisodeDataFromProlog{},
 		Serialization{},
+		SerializationPlusIO{},
 	};
 
 	printf("Results (%llu tests):\n", sizeof(tests)/sizeof(*tests));
-- 
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