/* Copyright (C) 2006   db4objects Inc.   http://www.db4o.com */

#include "Stdafx.h"
#include "NativeIoAdapter.h"

using namespace System;
using namespace System::IO;
using namespace System::Runtime::InteropServices;

using namespace cli;

#define LPCWSTR_FROM_MSTR(x) ((LPCWSTR) Marshal::StringToHGlobalUni(x).ToPointer())
#define FREE_LPCWSTR(x) (Marshal::FreeHGlobal(IntPtr((void *)x)))
#define SEEK(h,p) (SetFilePointerEx(h, *reinterpret_cast<LARGE_INTEGER*>(&p), 0, FILE_BEGIN))

namespace Db4objects
{
namespace Db4o
{
namespace IO
{

IoAdapter ^NativeIoAdapter::Open(String ^path, bool lock, long long initialLength)
{
	LPCWSTR file = LPCWSTR_FROM_MSTR(path);
	m_handle = CreateFile(
		file,
		GENERIC_READ | GENERIC_WRITE,
		lock ? NULL : FILE_SHARE_READ | FILE_SHARE_WRITE,
		NULL,
		OPEN_ALWAYS,
		FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS | FILE_FLAG_SEQUENTIAL_SCAN,
		NULL);

	FREE_LPCWSTR(file);

	if (m_handle == INVALID_HANDLE_VALUE)
		throw gcnew IOException(String::Concat("Failed to get an handle to ", path));

	if (initialLength > 0)
	{
		Seek(initialLength - 1);
		Write (gcnew array<unsigned char> {0}, 1);
	}

	return this;
}

long long NativeIoAdapter::GetLength()
{
	return (long long)GetFileSize(m_handle, NULL);
}

int NativeIoAdapter::Read(array<unsigned char> ^bytes, int length)
{
	DWORD read;
	pin_ptr<unsigned char> pb = &bytes[0];
	ReadFile(m_handle, pb, length, &read, NULL);
	return (int)read;
}

void NativeIoAdapter::Seek(long long position)
{
	SEEK(m_handle, position);
}

void NativeIoAdapter::Sync()
{
	FlushFileBuffers(m_handle);
}

void NativeIoAdapter::Write(array<unsigned char> ^bytes, int length)
{
	pin_ptr<unsigned char> pb = &bytes[0];
	WriteFile(m_handle, pb, length, NULL, NULL);
}

//void NativeIoAdapter::Copy(long long oldAddress, long long newAddress, int length)
//{
//	DWORD cbRead = 0;
//	void* buffer = LocalAlloc(LMEM_FIXED, length);
//	if (NULL != buffer)
//	{
//		SEEK(m_handle, oldAddress);
//		ReadFile(m_handle, buffer, length, &cbRead, NULL);
//		if (cbRead == length)
//		{
//			DWORD cbWritten = 0;
//			SEEK(m_handle, newAddress);
//			WriteFile(m_handle, buffer, length, &cbWritten, NULL);
//		}
//
//		LocalFree(buffer);
//	}
//}

void NativeIoAdapter::Close()
{
	CloseHandle(m_handle);
}

void NativeIoAdapter::Delete(String ^path)
{
	File::Delete(path);
}

bool NativeIoAdapter::Exists(String ^path)
{
	return File::Exists(path);
}

}
}
}