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

#include "stdafx.h"
#include "NativeIoAdapter.h"

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

using namespace Db4objects::Db4o::IO;

#define LPCWSTR_FROM_MSTR(x) ((LPCWSTR) Marshal::StringToHGlobalUni(x).ToPointer())
#define FREE_LPCWSTR(x) (Marshal::FreeHGlobal(IntPtr((void *)x)))

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,
		NULL,
		NULL);

	FREE_LPCWSTR(file);
	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)
{
	SetFilePointer(m_handle, position, 0, FILE_BEGIN);
}

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

void NativeIoAdapter::Delete(String ^path)
{
	LPCWSTR file = LPCWSTR_FROM_MSTR(path);
	DeleteFileW(file);
	FREE_LPCWSTR(file);
}

bool NativeIoAdapter::Exists(String ^path)
{
	bool exists;
	LPCWSTR file = LPCWSTR_FROM_MSTR(path);
	HANDLE handle = CreateFile(
		file,
		GENERIC_READ,
		NULL,
		NULL,
		OPEN_EXISTING,
		NULL,
		NULL);
	FREE_LPCWSTR(file);
	exists = handle != INVALID_HANDLE_VALUE;
	CloseHandle(handle);
	
	return exists;
}