/*
Miranda Database Tool
Copyright (C) 2001-2005  Richard Hughes

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/
#include "dbtool.h"

extern DWORD spaceProcessed, sourceFileSize;

int SignatureValid(DWORD ofs, DWORD signature)
{
	DWORD sig;

	if (ofs+sizeof(sig) >= sourceFileSize)	{
		AddToStatus(STATUS_ERROR, TranslateT("Invalid offset found (database truncated?)"));
		return 0;
	}

	sig = *(DWORD*)(opts.pFile+ofs);

	return sig == signature;
}

int PeekSegment(DWORD ofs, PVOID buf, int cbBytes)
{
	DWORD bytesRead;

	if (ofs >= sourceFileSize) {
		AddToStatus(STATUS_ERROR, TranslateT("Invalid offset found"));
		return ERROR_SEEK;
	}

	if (ofs+cbBytes>sourceFileSize)
		bytesRead = sourceFileSize - ofs;
	else
		bytesRead = cbBytes;

	if (bytesRead == 0) {
		AddToStatus(STATUS_ERROR, TranslateT("Error reading, database truncated? (%u)"), GetLastError());
		return ERROR_READ_FAULT;
	}

	CopyMemory(buf, opts.pFile+ofs, bytesRead);

	if ((int)bytesRead<cbBytes) return ERROR_HANDLE_EOF;
	return ERROR_SUCCESS;
}

int ReadSegment(DWORD ofs, PVOID buf, int cbBytes)
{
	int ret;

	ret = PeekSegment(ofs, buf, cbBytes);
	if (ret != ERROR_SUCCESS && ret != ERROR_HANDLE_EOF) return ret;

	if (opts.bAggressive) {
		if (ofs+cbBytes>sourceFileSize) {
			AddToStatus(STATUS_WARNING, TranslateT("Can't write to working file, aggressive mode may be too aggressive now"));
			ZeroMemory(opts.pFile+ofs, sourceFileSize-ofs);
		}
		else
			ZeroMemory(opts.pFile+ofs, cbBytes);
	}
	spaceProcessed += cbBytes;
	return ERROR_SUCCESS;
}

DWORD WriteSegment(DWORD ofs, PVOID buf, int cbBytes)
{
	DWORD bytesWritten;
	if (opts.bCheckOnly) return 0xbfbfbfbf;
	if (ofs == WSOFS_END) {
		ofs = dbhdr.ofsFileEnd;
		dbhdr.ofsFileEnd += cbBytes;
	}
	SetFilePointer(opts.hOutFile, ofs, NULL, FILE_BEGIN);
	WriteFile(opts.hOutFile, buf, cbBytes, &bytesWritten, NULL);
	if ((int)bytesWritten<cbBytes) {
		AddToStatus(STATUS_FATAL, TranslateT("Can't write to output file - disk full? (%u)"), GetLastError());
		return WS_ERROR;
	}
	return ofs;
}


int ReadWrittenSegment(DWORD ofs, PVOID buf, int cbBytes)
{
	DWORD bytesRead;
	if (opts.bCheckOnly) return 0xbfbfbfbf;
	if (ofs + cbBytes > dbhdr.ofsFileEnd)
		return ERROR_SEEK;

	SetFilePointer(opts.hOutFile, ofs, NULL, FILE_BEGIN);
	ReadFile(opts.hOutFile, buf, cbBytes, &bytesRead, NULL);
	if ((int)bytesRead<cbBytes)
		return ERROR_READ_FAULT;

	return ERROR_SUCCESS;
}